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Sambe BS, Sarr I, Diagne A, Diatta AS, Faye J, Diagne N, Diaw SOM, Mbodj AF, Sané R, Wotodjo AN, Diouf B, Thiam A, Diamanka A, Faye N, Sembène PM, Sarr FD, Dia I, Vigan-Womas I, Sokhna C, Toure-Balde A, Niang M. Persistent carriage of subpatent Plasmodium falciparum parasites associated with clinical malaria in a low transmission area in Senegal. Int J Infect Dis 2024; 147:107211. [PMID: 39151787 DOI: 10.1016/j.ijid.2024.107211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Revised: 08/05/2024] [Accepted: 08/11/2024] [Indexed: 08/19/2024] Open
Abstract
OBJECTIVES In low malaria transmission areas, the elimination of the disease has been hampered partly by the existence of a reservoir of subpatent Plasmodium falciparum infections within communities. This reservoir, often undetected, serves as a source of parasites and contributes to ongoing transmission and clinical malaria cases. METHODS This study, spanning a period of 9 years from June 2014 to December 2022, examined individual variations and long-term subpatent P. falciparum carriage in two matched cohorts of 44 individuals each living in Dielmo village in the Sudanian area of Senegal. Biannual blood samples, collected in June/July and December of each year, underwent P. falciparum diagnosis by quantitative polymerase chain reaction. QGIS and R analytical tools were used to map infections, assess the occurrence and clustering of subpatent and clinical P. falciparum infections, and determine the risk of infection in the vicinity of asymptomatic P. falciparum carriers. RESULTS The point frequency and long-term P. falciparum carriage were significantly higher among the quantitative polymerase chain reaction (qPCR) positive cohort compared to the negative cohort across the 16 cross-sectional surveys analyzed in this study (19.76% vs 10.99%, P-value <0.001). Asymptomatic carriage events in qPCR-positive group were 18.86 ± 1.72% and significantly greater (P-value = 0.001) than in the qPCR-negative group (11.32 ± 1.32%). The relative risk of P. falciparum infection or clinical malaria calculated with a 95% confidence interval significantly increased in the vicinity of infected individuals and was 1.44 (P-value = 0.53) and 2.64 (P-value = 0.04) when at least one individual in the direct (household) or indirect (block of households) vicinity is infected, respectively. The risk increased to 3.64 (P-value <0.001) if at least 1/5 of individuals in the indirect vicinity were P. falciparum-infected. CONCLUSIONS The study provides a detailed qualitative and quantitative analysis of the asymptomatic P. falciparum reservoir and its temporal and spatial dynamics within two subgroups of P. falciparum-infected and non-infected individuals in Dielmo village. It identified high-risk populations known as "hotpops" and hotspots that could be targeted by innovative interventions to accelerate the elimination of malaria in Dielmo village.
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Affiliation(s)
- Babacar Souleymane Sambe
- Institut Pasteur de Dakar, Pôle Immunophysiopathologie et Maladies Infectieuses, 36 avenue Pasteur, Dakar, Senegal
| | - Ibrahima Sarr
- Institut Pasteur de Dakar, Pôle Immunophysiopathologie et Maladies Infectieuses, 36 avenue Pasteur, Dakar, Senegal; Département de Biologie Animale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop de Dakar, Dakar Fann, Senegal
| | - Aissatou Diagne
- Institut Pasteur de Dakar, Pôle Immunophysiopathologie et Maladies Infectieuses, 36 avenue Pasteur, Dakar, Senegal; Département de Biologie Animale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop de Dakar, Dakar Fann, Senegal
| | - Arona Sabène Diatta
- Institut Pasteur de Dakar, Pôle Immunophysiopathologie et Maladies Infectieuses, 36 avenue Pasteur, Dakar, Senegal
| | - Joseph Faye
- Institut Pasteur de Dakar, Pôle Epidémiologie, Recherche Clinique et Science des données, Dakar, Senegal
| | | | - Serigne Ousmane Mbacké Diaw
- Institut Pasteur de Dakar, Pôle Immunophysiopathologie et Maladies Infectieuses, 36 avenue Pasteur, Dakar, Senegal
| | - Adja Fatou Mbodj
- Institut Pasteur de Dakar, Pôle Immunophysiopathologie et Maladies Infectieuses, 36 avenue Pasteur, Dakar, Senegal
| | - Rokhaya Sané
- Institut Pasteur de Dakar, Pôle Immunophysiopathologie et Maladies Infectieuses, 36 avenue Pasteur, Dakar, Senegal; Département de Biologie Animale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop de Dakar, Dakar Fann, Senegal
| | | | - Babacar Diouf
- Institut Pasteur de Dakar, Pôle Immunophysiopathologie et Maladies Infectieuses, 36 avenue Pasteur, Dakar, Senegal
| | - Alassane Thiam
- Institut Pasteur de Dakar, Pôle Immunophysiopathologie et Maladies Infectieuses, 36 avenue Pasteur, Dakar, Senegal
| | - Arfang Diamanka
- Département de Biologie Animale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop de Dakar, Dakar Fann, Senegal
| | - Ngor Faye
- Département de Biologie Animale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop de Dakar, Dakar Fann, Senegal
| | - Papa Mbacké Sembène
- Département de Biologie Animale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop de Dakar, Dakar Fann, Senegal
| | - Fatoumata Diene Sarr
- Institut Pasteur de Dakar, Pôle Epidémiologie, Recherche Clinique et Science des données, Dakar, Senegal
| | - Ibrahima Dia
- Institut Pasteur de Dakar, Pôle Zoologie Médicale, Dakar, Senegal
| | - Inès Vigan-Womas
- Institut Pasteur de Dakar, Pôle Immunophysiopathologie et Maladies Infectieuses, 36 avenue Pasteur, Dakar, Senegal
| | - Cheikh Sokhna
- EMR - MINES, Campus International IRD-UCAD de Hann, Dakar, Senegal
| | - Aissatou Toure-Balde
- Institut Pasteur de Dakar, Pôle Immunophysiopathologie et Maladies Infectieuses, 36 avenue Pasteur, Dakar, Senegal
| | - Makhtar Niang
- Institut Pasteur de Dakar, Pôle Immunophysiopathologie et Maladies Infectieuses, 36 avenue Pasteur, Dakar, Senegal.
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Abossie A, Demissew A, Getachew H, Tsegaye A, Degefa T, Habtamu K, Zhong D, Wang X, Lee MC, Zhou G, King CL, Kazura JW, Yan G, Yewhalaw D. Higher outdoor mosquito density and Plasmodium infection rates in and around malaria index case households in low transmission settings of Ethiopia: Implications for vector control. Parasit Vectors 2024; 17:53. [PMID: 38321572 PMCID: PMC10848356 DOI: 10.1186/s13071-023-06088-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 12/07/2023] [Indexed: 02/08/2024] Open
Abstract
BACKGROUND Understanding the clustering of infections for persistent malaria transmission is critical to determining how and where to target specific interventions. This study aimed to determine the density, blood meal sources and malaria transmission risk of anopheline vectors by targeting malaria index cases, their neighboring households and control villages in Arjo-Didessa, southwestern Ethiopia. METHODS An entomological study was conducted concurrently with a reactive case detection (RCD) study from November 2019 to October 2021 in Arjo Didessa and the surrounding vicinity, southwestern Ethiopia. Anopheline mosquitoes were collected indoors and outdoors in index case households and their surrounding households (neighboring households), as well as in control households, using pyrethrum spray cache (PSC) and U.S. Centers for Disease Control and Prevention (CDC) light traps. Adult mosquitoes were morphologically identified, and speciation in the Anopheles gambiae complex was done by PCR. Mosquito Plasmodium infections and host blood meal sources were detected by circumsporozoite protein enzyme-linked immunosorbent assay (CSP-ELISA) and cytochrome b-based blood meal PCR, respectively. RESULTS Among the 770 anopheline mosquitoes collected, An. gambiae sensu lato (A. gambiae s.l.) was the predominant species, accounting for 87.1% (n = 671/770) of the catch, followed by the Anopheles coustani complex and Anopheles pharoensis, which accounted for 12.6% (n = 97/770) and 0.26% (n = 2/770) of the catch, respectively. From the sub-samples of An. gambiae s.l.analyzed with PCR, An. arabiensis and Anopheles amharicus were identified. The overall mean density of mosquitoes was 1.26 mosquitoes per trap per night using the CDC light traps. Outdoor mosquito density was significantly higher than indoor mosquito density in the index and neighboring households (P = 0.0001). The human blood index (HBI) and bovine blood index (BBI) of An. arabiensis were 20.8% (n = 34/168) and 24.0% (n = 41/168), respectively. The overall Plasmodium sporozoite infection rate of anophelines (An. arabiensis and An. coustani complex) was 4.4% (n = 34/770). Sporozoites were detected indoors and outdoors in captured anopheline mosquitoes. Of these CSP-positive species for Pv-210, Pv-247 and Pf, 41.1% (n = 14/34) were captured outdoors. A significantly higher proportion of sporozoite-infected mosquitoes were caught in index case households (5.6%, n = 8/141) compared to control households (1.1%, n = 2/181) (P = 0.02), and in neighboring households (5.3%, n = 24/448) compared to control households (P = 0.01). CONCLUSIONS The findings of this study indicated that malaria index cases and their neighboring households had higher outdoor mosquito densities and Plasmodium infection rates. The study also highlighted a relatively higher outdoor mosquito density, which could increase the potential risk of outdoor malaria transmission and may play a role in residual malaria transmission. Thus, it is important to strengthen the implementation of vector control interventions, such as targeted indoor residual spraying, long-lasting insecticidal nets and other supplementary vector control measures such as larval source management and community engagement approaches. Furthermore, in low transmission settings, such as the Arjo Didessa Sugarcane Plantation, providing health education to local communities, enhanced environmental management and entomological surveillance, along with case detection and management by targeting of malaria index cases and their immediate neighboring households, could be important measures to control residual malaria transmission and achieve the targeted elimination goals.
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Affiliation(s)
- Ashenafi Abossie
- Department of Medical Laboratory Sciences, College of Medicine and Health Sciences, Arba Minch University, Arba Minch, Ethiopia.
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia.
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia.
| | - Assalif Demissew
- Department of Medical Laboratory Sciences, College of Medicine and Health Sciences, Ambo University, Ambo, Ethiopia
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Hallelujah Getachew
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
- Department of Medical Laboratory Technology, Arba Minch College of Health Sciences, Arba Minch, Ethiopia
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Arega Tsegaye
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
- Department of Biology, College of Natural Science, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Teshome Degefa
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Kassahun Habtamu
- Menelik II College of Health Sciences, Addis Ababa, Ethiopia
- Department of Microbial, Cellular and Molecular Biology, College of Natural Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Daibin Zhong
- Program in Public Health, University of California at Irvine, Irvine, CA, 92697, USA
| | - Xiaoming Wang
- Program in Public Health, University of California at Irvine, Irvine, CA, 92697, USA
| | - Ming-Chieh Lee
- Program in Public Health, University of California at Irvine, Irvine, CA, 92697, USA
| | - Guofa Zhou
- Program in Public Health, University of California at Irvine, Irvine, CA, 92697, USA
| | - Christopher L King
- Center for Global Health & Diseases, School of Medicine, Case Western Reserve University, Cleveland, 44106 OH, USA
| | - James W Kazura
- Center for Global Health & Diseases, School of Medicine, Case Western Reserve University, Cleveland, 44106 OH, USA
| | - Guiyun Yan
- Program in Public Health, University of California at Irvine, Irvine, CA, 92697, USA
| | - Delenasaw Yewhalaw
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
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Chang W, Cohen J, Wang DQ, Abdulla S, Mahende MK, Gavana T, Scott V, Msuya HM, Mwanyika-Sando M, Njau RJA, Lu SN, Temu S, Masanja H, Anthony W, Aregawi W M, Sunder N, Kun T, Bruxvoort K, Kitau J, Kihwele F, Chila G, Michael M, Castro M, Menzies NA, Kim S, Ning X, Zhou XN, Chaki P, Mlacha YP. Impact of 1,7-malaria reactive community-based testing and response (1,7-mRCTR) approach on malaria prevalence in Tanzania. Infect Dis Poverty 2023; 12:116. [PMID: 38105258 PMCID: PMC10726614 DOI: 10.1186/s40249-023-01166-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 11/20/2023] [Indexed: 12/19/2023] Open
Abstract
BACKGROUND Progress in malaria control has stalled in recent years and innovative surveillance and response approaches are needed to accelerate malaria control and elimination efforts in endemic areas of Africa. Building on a previous China-UK-Tanzania pilot study on malaria control, this study aimed to assess the impact of the 1,7-malaria Reactive Community-Based Testing and Response (1,7-mRCTR) approach implemented over two years in three districts of Tanzania. METHODS The 1,7-mRCTR approach provides community-based malaria testing via rapid diagnostic tests and treatment in villages with the highest burden of malaria incidence based on surveillance data from health facilities. We used a difference-in-differences quasi-experimental design with linear probability models and two waves of cross-sectional household surveys to assess the impact of 1,7-mRCTR on malaria prevalence. We conducted sensitivity analyses to assess the robustness of our results, examined how intervention effects varied in subgroups, and explored alternative explanations for the observed results. RESULTS Between October 2019 and September 2021, 244,771 community-based malaria rapid tests were completed in intervention areas, and each intervention village received an average of 3.85 rounds of 1-7mRCTR. Malaria prevalence declined from 27.4% at baseline to 11.7% at endline in the intervention areas and from 26.0% to 16.0% in the control areas. 1,7-mRCTR was associated with a 4.5-percentage-point decrease in malaria prevalence (95% confidence interval: - 0.067, - 0.023), equivalent to a 17% reduction from the baseline. In Rufiji, a district characterized by lower prevalence and where larviciding was additionally provided, 1,7-mRCTR was associated with a 63.9% decline in malaria prevalence. CONCLUSIONS The 1,7-mRCTR approach reduced malaria prevalence. Despite implementation interruptions due to the COVID-19 pandemic and supply chain challenges, the study provided novel evidence on the effectiveness of community-based reactive approaches in moderate- to high-endemicity areas and demonstrated the potential of South-South cooperation in tackling global health challenges.
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Affiliation(s)
- Wei Chang
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Jessica Cohen
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Duo-Quan Wang
- Chinese Center for Disease Control and Prevention, National Institute of Parasitic Diseases, Shanghai, People's Republic of China
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
- Chinese Center for Tropical Diseases Research, Shanghai, People's Republic of China
- WHO Collaborating Centre for Tropical Diseases, Shanghai, People's Republic of China
- National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Shanghai, People's Republic of China
- Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, People's Republic of China
| | - Salim Abdulla
- Ifakara Health Institute, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78 373, Dar es Salaam, United Republic of Tanzania
| | - Muhidin Kassim Mahende
- Ifakara Health Institute, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78 373, Dar es Salaam, United Republic of Tanzania
| | - Tegemeo Gavana
- Ifakara Health Institute, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78 373, Dar es Salaam, United Republic of Tanzania
| | - Valerie Scott
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Hajirani M Msuya
- Ifakara Health Institute, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78 373, Dar es Salaam, United Republic of Tanzania
| | | | - Ritha John A Njau
- Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Shen-Ning Lu
- Chinese Center for Disease Control and Prevention, National Institute of Parasitic Diseases, Shanghai, People's Republic of China
- Chinese Center for Tropical Diseases Research, Shanghai, People's Republic of China
- WHO Collaborating Centre for Tropical Diseases, Shanghai, People's Republic of China
- National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Shanghai, People's Republic of China
- Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, People's Republic of China
| | - Silas Temu
- Ifakara Health Institute, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78 373, Dar es Salaam, United Republic of Tanzania
| | - Honorati Masanja
- Ifakara Health Institute, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78 373, Dar es Salaam, United Republic of Tanzania
| | | | - Maru Aregawi W
- Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | | | - Tang Kun
- Vanke School of Public Health, Tsinghua University, Beijing, People's Republic of China
| | - Katia Bruxvoort
- School of Public Health, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jovin Kitau
- Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | - Fadhila Kihwele
- Ifakara Health Institute, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78 373, Dar es Salaam, United Republic of Tanzania
| | - Godlove Chila
- Ifakara Health Institute, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78 373, Dar es Salaam, United Republic of Tanzania
| | - Mihayo Michael
- Ifakara Health Institute, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78 373, Dar es Salaam, United Republic of Tanzania
| | - Marcia Castro
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Nicolas A Menzies
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Sein Kim
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Xiao Ning
- Chinese Center for Disease Control and Prevention, National Institute of Parasitic Diseases, Shanghai, People's Republic of China
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
- Chinese Center for Tropical Diseases Research, Shanghai, People's Republic of China
- WHO Collaborating Centre for Tropical Diseases, Shanghai, People's Republic of China
- National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Shanghai, People's Republic of China
- Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, People's Republic of China
| | - Xiao-Nong Zhou
- Chinese Center for Disease Control and Prevention, National Institute of Parasitic Diseases, Shanghai, People's Republic of China
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
- Chinese Center for Tropical Diseases Research, Shanghai, People's Republic of China
- WHO Collaborating Centre for Tropical Diseases, Shanghai, People's Republic of China
- National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Shanghai, People's Republic of China
- Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, People's Republic of China
| | - Prosper Chaki
- Ifakara Health Institute, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78 373, Dar es Salaam, United Republic of Tanzania
- The Pan-African Mosquito Control Association (PAMCA), KEMRI Headquarters, Mbagathi Road, Nairobi, 54840-00200, Kenya
| | - Yeromin P Mlacha
- Ifakara Health Institute, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78 373, Dar es Salaam, United Republic of Tanzania.
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Mkali HR, Lalji SM, Al-Mafazy AW, Joseph JJ, Mwaipape OS, Ali AS, Abbas FB, Ali MH, Hassan WS, Reaves EJ, Kitojo C, Serbantez N, Kabula BI, Nyinondi SS, McKay M, Cressman G, Ngondi JM, Reithinger R. How Real-Time Case-Based Malaria Surveillance Helps Zanzibar Get a Step Closer to Malaria Elimination: Description of Operational Platform and Resources. GLOBAL HEALTH, SCIENCE AND PRACTICE 2023; 11:e2200522. [PMID: 37903584 PMCID: PMC10615242 DOI: 10.9745/ghsp-d-22-00522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 09/26/2023] [Indexed: 11/01/2023]
Abstract
Testing and treating asymptomatic populations have the potential to reduce the population's parasite reservoir and reduce malaria transmission. Zanzibar's malaria case notification (MCN) platform collects detailed sociodemographic and epidemiological data from all confirmed malaria cases to inform programmatic decision-making. We describe the design and operationalization process of the platform and other malaria surveillance resources that are enabling Zanzibar's progress toward malaria elimination.The MCN platform consists of an interactive short message service (SMS) system for case notification, a software application for Android mobile devices, a visual question set and workflow manager, a back-end database server, and a web browser-based application for data analytics, configuration, and management. Malaria case data were collected from August 2012 to December 2021 and reported via SMS from all public and private health facilities to a central database and then to district malaria surveillance officers' mobile devices. Data included patient names, shehia (administrative area), and date of diagnosis, enabling officers to track patients, ideally within 24 hours of reporting. Patients' household members were tested for malaria using conventional rapid diagnostic tests (RDTs). Treatment using artemisinin-based combination therapy was provided for persons testing positive.Between 2012 and 2021, a total of 48,899 index malaria cases were confirmed at health facilities, 22,152 (45.3%) within 24 hours of reporting; 41,886 (85.7%) cases were fully investigated and followed up to the household level. A total of 111,811 additional household members were tested with RDTs, of whom 10,602 (9.5%) were malaria positive.The MCN platform reports malaria case data in near real time, enabling prompt follow-up of index cases and prompt testing and treatment of members in index case households. Along with routine testing and treatment and other preventive interventions, the MCN platform is foundational to the programmatic efforts in further reducing malaria and ultimately eliminating autochthonous malaria transmission in Zanzibar.
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Affiliation(s)
| | - Shabbir M Lalji
- RTI International, Dar es Salaam, United Republic of Tanzania
| | | | - Joseph J Joseph
- RTI International, Dar es Salaam, United Republic of Tanzania
| | - Osia S Mwaipape
- RTI International, Dar es Salaam, United Republic of Tanzania
| | - Abdullah S Ali
- Zanzibar Malaria Elimination Programme, Ministry of Health, Zanzibar, United Republic of Tanzania
| | - Faiza B Abbas
- Zanzibar Malaria Elimination Programme, Ministry of Health, Zanzibar, United Republic of Tanzania
| | - Mohamed H Ali
- Zanzibar Malaria Elimination Programme, Ministry of Health, Zanzibar, United Republic of Tanzania
| | - Wahida S Hassan
- Zanzibar Malaria Elimination Programme, Ministry of Health, Zanzibar, United Republic of Tanzania
| | - Erik J Reaves
- U.S. President's Malaria Initiative, U.S. Centers for Disease Control and Prevention, Dar es Salaam, United Republic of Tanzania
| | - Chonge Kitojo
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Dar es Salaam, United Republic of Tanzania
| | - Naomi Serbantez
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Dar es Salaam, United Republic of Tanzania
| | - Bilali I Kabula
- RTI International, Dar es Salaam, United Republic of Tanzania
| | | | - Mike McKay
- RTI International, Research Triangle Park, USA
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5
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Newby G, Cotter C, Roh ME, Harvard K, Bennett A, Hwang J, Chitnis N, Fine S, Stresman G, Chen I, Gosling R, Hsiang MS. Testing and treatment for malaria elimination: a systematic review. Malar J 2023; 22:254. [PMID: 37661286 PMCID: PMC10476355 DOI: 10.1186/s12936-023-04670-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 08/07/2023] [Indexed: 09/05/2023] Open
Abstract
BACKGROUND Global interest in malaria elimination has prompted research on active test and treat (TaT) strategies. METHODS A systematic review and meta-analysis were conducted to assess the effectiveness of TaT strategies to reduce malaria transmission. RESULTS A total of 72 empirical research and 24 modelling studies were identified, mainly focused on proactive mass TaT (MTaT) and reactive case detection (RACD) in higher and lower transmission settings, respectively. Ten intervention studies compared MTaT to no MTaT and the evidence for impact on malaria incidence was weak. No intervention studies compared RACD to no RACD. Compared to passive case detection (PCD) alone, PCD + RACD using standard diagnostics increased infection detection 52.7% and 11.3% in low and very low transmission settings, respectively. Using molecular methods increased this detection of infections by 1.4- and 1.1-fold, respectively. CONCLUSION Results suggest MTaT is not effective for reducing transmission. By increasing case detection, surveillance data provided by RACD may indirectly reduce transmission by informing coordinated responses of intervention targeting.
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Affiliation(s)
- Gretchen Newby
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco (UCSF), 550 16th Street, San Francisco, CA, 94143, USA
| | - Chris Cotter
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco (UCSF), 550 16th Street, San Francisco, CA, 94143, USA
- Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden
| | - Michelle E Roh
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco (UCSF), 550 16th Street, San Francisco, CA, 94143, USA
- Department of Epidemiology and Biostatistics, UCSF, San Francisco, CA, USA
| | - Kelly Harvard
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco (UCSF), 550 16th Street, San Francisco, CA, 94143, USA
| | - Adam Bennett
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco (UCSF), 550 16th Street, San Francisco, CA, 94143, USA
- Department of Epidemiology and Biostatistics, UCSF, San Francisco, CA, USA
- PATH, Seattle, WA, USA
| | - Jimee Hwang
- Malaria Branch, Centers for Disease Control and Prevention, U.S. President's Malaria Initiative, Atlanta, GA, USA
| | - Nakul Chitnis
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Sydney Fine
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco (UCSF), 550 16th Street, San Francisco, CA, 94143, USA
| | - Gillian Stresman
- College of Public Health, University of South Florida, Tampa, FL, USA
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK
| | - Ingrid Chen
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco (UCSF), 550 16th Street, San Francisco, CA, 94143, USA
- Department of Epidemiology and Biostatistics, UCSF, San Francisco, CA, USA
| | - Roly Gosling
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco (UCSF), 550 16th Street, San Francisco, CA, 94143, USA
- Department of Epidemiology and Biostatistics, UCSF, San Francisco, CA, USA
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Michelle S Hsiang
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California San Francisco (UCSF), 550 16th Street, San Francisco, CA, 94143, USA.
- Department of Epidemiology and Biostatistics, UCSF, San Francisco, CA, USA.
- Department of Pediatrics, UCSF, San Francisco, CA, USA.
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6
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van Dijk N, Carter J, Omondi W, Mens P, Schallig H. Clinical features, immunological interactions and household determinants of visceral leishmaniasis and malaria coinfections in West Pokot, Kenya: protocol for an observational study. BMJ Open 2023; 13:e068679. [PMID: 37068901 PMCID: PMC10111886 DOI: 10.1136/bmjopen-2022-068679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/19/2023] Open
Abstract
INTRODUCTION Visceral leishmaniasis (VL) and malaria are two deadly parasitic diseases that coexist in West Pokot County, Kenya. The local population is at considerable risk of coinfection with VL and malaria; however, few studies have described the clinical implications of this comorbidity. Questions remain regarding the immune responses responsible for possible predisposing or protective effects. Moreover, characterisation of environmental and household risk factors for co-acquiring VL and malaria is warranted to increase awareness and guide implementation of targeted control strategies. This protocol intends to address these knowledge gaps concerning VL-malaria coinfections. METHODS AND ANALYSIS This observational research project will have a multimethod approach, starting with a cross-sectional study at Kacheliba Sub-County Hospital in West Pokot, Kenya. Patients with laboratory confirmation of a VL and/or malaria infection will be clinically assessed and symptomatology of monoinfections and coinfections will be compared. Second, a questionnaire will be addressed to all included patients and to healthy controls in local communities. This case-control study will aim to describe household and environmental determinants associated with VL-malaria coinfection. Lastly, blood samples will be collected from a small cohort of VL and malaria monoinfected and coinfected patients during treatment of their infection(s), and from healthy controls and asymptomatic VL and malaria cases recruited in local communities. These specimens will be used for serum cytokine measurements and molecular quantitation of Plasmodium and Leishmania. In this way, the immune response and parasite dynamics during VL-malaria coinfection will be characterised longitudinally and compared with those observed in clinical and asymptomatic monoinfections. ETHICS AND DISSEMINATION Ethical approval was obtained from the Ethics and Scientific Research Committee of Amref Health Africa. The study findings will be presented at international conferences and published in open-access, peer-reviewed journals. TRIAL REGISTRATION NUMBER ISRCTN Registry (ISRCTN15023306).
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Affiliation(s)
- Norbert van Dijk
- Department of Medical Microbiology and Infection Prevention, Amsterdam University Medical Centres, Academic Medical Centre at the University of Amsterdam, Amsterdam, The Netherlands
- Infectious Diseases Programme, Amsterdam Institute for Infection and Immunity, Amsterdam, The Netherlands
| | - Jane Carter
- Clinical and Diagnostics Programme, Amref Health Africa, Nairobi, Kenya
| | - Wyckliff Omondi
- Division of Vector Borne and Neglected Tropical Diseases, Kenya Ministry of Health, Nairobi, Kenya
| | - Petra Mens
- Department of Medical Microbiology and Infection Prevention, Amsterdam University Medical Centres, Academic Medical Centre at the University of Amsterdam, Amsterdam, The Netherlands
- Infectious Diseases Programme, Amsterdam Institute for Infection and Immunity, Amsterdam, The Netherlands
| | - Henk Schallig
- Department of Medical Microbiology and Infection Prevention, Amsterdam University Medical Centres, Academic Medical Centre at the University of Amsterdam, Amsterdam, The Netherlands
- Infectious Diseases Programme, Amsterdam Institute for Infection and Immunity, Amsterdam, The Netherlands
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7
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Aidoo EK, Aboagye FT, Botchway FA, Osei-Adjei G, Appiah M, Duku-Takyi R, Sakyi SA, Amoah L, Badu K, Asmah RH, Lawson BW, Krogfelt KA. Reactive Case Detection Strategy for Malaria Control and Elimination: A 12 Year Systematic Review and Meta-Analysis from 25 Malaria-Endemic Countries. Trop Med Infect Dis 2023; 8:180. [PMID: 36977181 PMCID: PMC10058581 DOI: 10.3390/tropicalmed8030180] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 02/23/2023] [Accepted: 03/09/2023] [Indexed: 03/30/2023] Open
Abstract
Reactive case detection (RACD) is the screening of household members and neighbors of index cases reported in passive surveillance. This strategy seeks asymptomatic infections and provides treatment to break transmission without testing or treating the entire population. This review discusses and highlights RACD as a recommended strategy for the detection and elimination of asymptomatic malaria as it pertains in different countries. Relevant studies published between January 2010 and September 2022 were identified mainly through PubMed and Google Scholar. Search terms included "malaria and reactive case detection", "contact tracing", "focal screening", "case investigation", "focal screen and treat". MedCalc Software was used for data analysis, and the findings from the pooled studies were analyzed using a fixed-effect model. Summary outcomes were then presented using forest plots and tables. Fifty-four (54) studies were systematically reviewed. Of these studies, 7 met the eligibility criteria based on risk of malaria infection in individuals living with an index case < 5 years old, 13 met the eligibility criteria based on risk of malaria infection in an index case household member compared with a neighbor of an index case, and 29 met the eligibility criteria based on risk of malaria infection in individuals living with index cases, and were included in the meta-analysis. Individuals living in index case households with an average risk of 2.576 (2.540-2.612) were more at risk of malaria infection and showed pooled results of high variation heterogeneity chi-square = 235.600, (p < 0.0001) I2 = 98.88 [97.87-99.89]. The pooled results showed that neighbors of index cases were 0.352 [0.301-0.412] times more likely to have a malaria infection relative to index case household members, and this result was statistically significant (p < 0.001). The identification and treatment of infectious reservoirs is critical to successful malaria elimination. Evidence to support the clustering of infections in neighborhoods, which necessitates the inclusion of neighboring households as part of the RACD strategy, was presented in this review.
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Affiliation(s)
- Ebenezer Krampah Aidoo
- Department of Medical Laboratory Technology, Accra Technical University, Accra GP 561, Ghana; (F.A.B.); (G.O.-A.); (M.A.); (R.D.-T.)
| | - Frank Twum Aboagye
- Biomedical and Public Health Research Unit, Council for Scientific and Industrial Research-Water Research Institute, Accra AH 38, Ghana;
| | - Felix Abekah Botchway
- Department of Medical Laboratory Technology, Accra Technical University, Accra GP 561, Ghana; (F.A.B.); (G.O.-A.); (M.A.); (R.D.-T.)
| | - George Osei-Adjei
- Department of Medical Laboratory Technology, Accra Technical University, Accra GP 561, Ghana; (F.A.B.); (G.O.-A.); (M.A.); (R.D.-T.)
| | - Michael Appiah
- Department of Medical Laboratory Technology, Accra Technical University, Accra GP 561, Ghana; (F.A.B.); (G.O.-A.); (M.A.); (R.D.-T.)
| | - Ruth Duku-Takyi
- Department of Medical Laboratory Technology, Accra Technical University, Accra GP 561, Ghana; (F.A.B.); (G.O.-A.); (M.A.); (R.D.-T.)
| | - Samuel Asamoah Sakyi
- Department of Molecular Medicine, Kwame Nkrumah University of Science & Technology, University Post Office, Kumasi AK 039, Ghana;
| | - Linda Amoah
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra LG 581, Ghana;
| | - Kingsley Badu
- Department of Theoretical & Applied Biology, Kwame Nkrumah University of Science & Technology, University Post Office, Kumasi AK 039, Ghana; (K.B.); (B.W.L.)
| | - Richard Harry Asmah
- Department of Biomedical Sciences, School of Basic and Biomedical Science, University of Health & Allied Sciences, Ho PMB 31, Ghana;
| | - Bernard Walter Lawson
- Department of Theoretical & Applied Biology, Kwame Nkrumah University of Science & Technology, University Post Office, Kumasi AK 039, Ghana; (K.B.); (B.W.L.)
| | - Karen Angeliki Krogfelt
- Department of Science and Environment, Unit of Molecular and Medical Biology, The PandemiX Center, Roskilde University, 4000 Roskilde, Denmark
- Department of Virus and Microbiological Special Diagnostics, Statens Serum Institut, 2300 Copenhagen, Denmark
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8
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Bisanzio D, Lalji S, Abbas FB, Ali MH, Hassan W, Mkali HR, Al-Mafazy AW, Joseph JJ, Nyinondi S, Kitojo C, Serbantez N, Reaves E, Eckert E, Ngondi JM, Reithinger R. Spatiotemporal dynamics of malaria in Zanzibar, 2015-2020. BMJ Glob Health 2023; 8:bmjgh-2022-009566. [PMID: 36639160 PMCID: PMC9843203 DOI: 10.1136/bmjgh-2022-009566] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 12/21/2022] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Despite high coverage of malaria interventions, malaria elimination in Zanzibar remains elusive, with the annual number of cases increasing gradually over the last 3 years. OBJECTIVE The aims of the study were to (1) assess the spatiotemporal dynamics of malaria in Zanzibar between 2015 and 2020 and (2) identify malaria hotspots that would allow Zanzibar to develop an epidemiological stratification for more effective and granular intervention targeting. METHODS In this study, we analysed data routinely collected by Zanzibar's Malaria Case Notification (MCN) system. The system collects sociodemographic and epidemiological data from all malaria cases. Cases are passively detected at health facilities (ie, primary index cases) and through case follow-up and reactive case detection (ie, secondary cases). Analyses were performed to identify the spatial heterogeneity of case reporting at shehia (ward) level during transmission seasons. RESULTS From 1 January 2015 to 30 April 2020, the MCN system reported 22 686 index cases. Number of cases reported showed a declining trends from 2015 to 2016, followed by an increase from 2017 to 2020. More than 40% of cases had a travel history outside Zanzibar in the month prior to testing positive for malaria. The proportion of followed up index cases was approximately 70% for all years. Out of 387 shehias, 79 (20.4%) were identified as malaria hotspots in any given year; these hotspots reported 52% of all index cases during the study period. Of the 79 hotspot shehias, 12 were hotspots in more than 4 years, that is, considered temporally stable, reporting 14.5% of all index cases. CONCLUSIONS Our findings confirm that the scale-up of malaria interventions has greatly reduced malaria transmission in Zanzibar since 2006. Analyses identified hotspots, some of which were stable across multiple years. Malaria efforts should progress from a universal intervention coverage approach to an approach that is more tailored to a select number of hotspot shehias.
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Affiliation(s)
- Donal Bisanzio
- RTI International, Washington, District of Columbia, USA
| | - Shabbir Lalji
- RTI International, Dar es Salaam, United Republic of Tanzania
| | - Faiza B Abbas
- Zanzibar Malaria Elimination Programme, Ministry of Health, Stone Town, Zanzibar, United Republic of Tanzania
| | - Mohamed H Ali
- Zanzibar Malaria Elimination Programme, Ministry of Health, Stone Town, Zanzibar, United Republic of Tanzania
| | - Wahida Hassan
- Zanzibar Malaria Elimination Programme, Ministry of Health, Stone Town, Zanzibar, United Republic of Tanzania
| | | | | | - Joseph J Joseph
- RTI International, Dar es Salaam, United Republic of Tanzania
| | - Ssanyu Nyinondi
- RTI International, Dar es Salaam, United Republic of Tanzania
| | - Chonge Kitojo
- U.S. President’s Malaria Initiative, U.S. Agency for International Development, Dar es Salaam, United Republic of Tanzania
| | - Naomi Serbantez
- U.S. President’s Malaria Initiative, U.S. Agency for International Development, Dar es Salaam, United Republic of Tanzania
| | - Erik Reaves
- U.S. President’s Malaria Initiative, U.S. Centers for Disease Control, Dar es Salaam, United Republic of Tanzania
| | - Erin Eckert
- RTI International, Washington, District of Columbia, USA
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9
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Oduma CO, Ombok M, Zhao X, Huwe T, Ondigo BN, Kazura JW, Grieco J, Achee N, Liu F, Ochomo E, Koepfli C. Altitude, not potential larval habitat availability, explains pronounced variation in Plasmodium falciparum infection prevalence in the western Kenya highlands. PLOS GLOBAL PUBLIC HEALTH 2023; 3:e0001505. [PMID: 37068071 PMCID: PMC10109483 DOI: 10.1371/journal.pgph.0001505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 03/03/2023] [Indexed: 04/18/2023]
Abstract
Progress in malaria control has stalled over the recent years. Knowledge on main drivers of transmission explaining small-scale variation in prevalence can inform targeted control measures. We collected finger-prick blood samples from 3061 individuals irrespective of clinical symptoms in 20 clusters in Busia in western Kenya and screened for Plasmodium falciparum parasites using qPCR and microscopy. Clusters spanned an altitude range of 207 meters (1077-1284 m). We mapped potential mosquito larval habitats and determined their number within 250 m of a household and distances to households using ArcMap. Across all clusters, P. falciparum parasites were detected in 49.8% (1524/3061) of individuals by qPCR and 19.5% (596/3061) by microscopy. Across the clusters, prevalence ranged from 26% to 70% by qPCR. Three to 34 larval habitats per cluster and 0-17 habitats within a 250m radius around households were observed. Using a generalized linear mixed effect model (GLMM), a 5% decrease in the odds of getting infected per each 10m increase in altitude was observed, while the number of larval habitats and their proximity to households were not statistically significant predictors for prevalence. Kitchen located indoors, open eaves, a lower level of education of the household head, older age, and being male were significantly associated with higher prevalence. Pronounced variation in prevalence at small scales was observed and needs to be taken into account for malaria surveillance and control. Potential larval habitat frequency had no direct impact on prevalence.
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Affiliation(s)
- Colins O Oduma
- Department of Biochemistry and Molecular Biology, Egerton University, Nakuru, Kenya
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Maurice Ombok
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Xingyuan Zhao
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, IN, United States of America
| | - Tiffany Huwe
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States of America
| | - Bartholomew N Ondigo
- Department of Biochemistry and Molecular Biology, Egerton University, Nakuru, Kenya
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - James W Kazura
- Case Western Reserve University, Center for Global Health and Diseases, Cleveland, OH, United States of America
| | - John Grieco
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States of America
| | - Nicole Achee
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States of America
| | - Fang Liu
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, IN, United States of America
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States of America
| | - Eric Ochomo
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Cristian Koepfli
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States of America
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10
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Butzin-Dozier Z, Athni TS, Benjamin-Chung J. A Review of the Ring Trial Design for Evaluating Ring Interventions for Infectious Diseases. Epidemiol Rev 2022; 44:29-54. [PMID: 35593400 PMCID: PMC10362935 DOI: 10.1093/epirev/mxac003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 03/25/2022] [Accepted: 05/12/2022] [Indexed: 12/29/2022] Open
Abstract
In trials of infectious disease interventions, rare outcomes and unpredictable spatiotemporal variation can introduce bias, reduce statistical power, and prevent conclusive inferences. Spillover effects can complicate inference if individual randomization is used to gain efficiency. Ring trials are a type of cluster-randomized trial that may increase efficiency and minimize bias, particularly in emergency and elimination settings with strong clustering of infection. They can be used to evaluate ring interventions, which are delivered to individuals in proximity to or contact with index cases. We conducted a systematic review of ring trials, compare them with other trial designs for evaluating ring interventions, and describe strengths and weaknesses of each design. Of 849 articles and 322 protocols screened, we identified 26 ring trials, 15 cluster-randomized trials, 5 trials that randomized households or individuals within rings, and 1 individually randomized trial. The most common interventions were postexposure prophylaxis (n = 23) and focal mass drug administration and screening and treatment (n = 7). Ring trials require robust surveillance systems and contact tracing for directly transmitted diseases. For rare diseases with strong spatiotemporal clustering, they may have higher efficiency and internal validity than cluster-randomized designs, in part because they ensure that no clusters are excluded from analysis due to zero cluster incidence. Though more research is needed to compare them with other types of trials, ring trials hold promise as a design that can increase trial speed and efficiency while reducing bias.
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11
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Das AM, Hetzel MW, Yukich JO, Stuck L, Fakih BS, Al-Mafazy AWH, Ali A, Chitnis N. The impact of reactive case detection on malaria transmission in Zanzibar in the presence of human mobility. Epidemics 2022; 41:100639. [PMID: 36343496 PMCID: PMC9758615 DOI: 10.1016/j.epidem.2022.100639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 09/02/2022] [Accepted: 10/03/2022] [Indexed: 12/29/2022] Open
Abstract
Malaria persists at low levels on Zanzibar despite the use of vector control and case management. We use a metapopulation model to investigate the role of human mobility in malaria persistence on Zanzibar, and the impact of reactive case detection. The model was parameterized using survey data on malaria prevalence, reactive case detection, and travel history. We find that in the absence of imported cases from mainland Tanzania, malaria would likely cease to persist on Zanzibar. We also investigate potential intervention scenarios that may lead to elimination, especially through changes to reactive case detection. While we find that some additional cases are removed by reactive case detection, a large proportion of cases are missed due to many infections having a low parasite density that go undetected by rapid diagnostic tests, a low rate of those infected with malaria seeking treatment, and a low rate of follow up at the household level of malaria cases detected at health facilities. While improvements in reactive case detection would lead to a reduction in malaria prevalence, none of the intervention scenarios tested here were sufficient to reach elimination. Imported cases need to be treated to have a substantial impact on prevalence.
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Affiliation(s)
- Aatreyee M Das
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland; University of Basel, Basel, Switzerland.
| | - Manuel W Hetzel
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland; University of Basel, Basel, Switzerland
| | - Joshua O Yukich
- Center for Applied Malaria Research and Evaluation, Department of Tropical Medicine, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Logan Stuck
- Center for Applied Malaria Research and Evaluation, Department of Tropical Medicine, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Bakar S Fakih
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland; University of Basel, Basel, Switzerland; Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
| | | | - Abdullah Ali
- Zanzibar Malaria Elimination Programme, Zanzibar, United Republic of Tanzania
| | - Nakul Chitnis
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland; University of Basel, Basel, Switzerland
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12
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Gautam R, Pokharel A, Adhikari K, Uprety KN, Vaidya NK. Modeling malaria transmission in Nepal: impact of imported cases through cross-border mobility. JOURNAL OF BIOLOGICAL DYNAMICS 2022; 16:528-564. [PMID: 35833562 DOI: 10.1080/17513758.2022.2096935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 06/24/2022] [Indexed: 06/15/2023]
Abstract
The cross-border mobility of malaria cases poses an obstacle to malaria elimination programmes in many countries, including Nepal. Here, we develop a novel mathematical model to study how the imported malaria cases through the Nepal-India open-border affect the Nepal government's goal of eliminating malaria by 2026. Mathematical analyses and numerical simulations of our model, validated by malaria case data from Nepal, indicate that eliminating malaria from Nepal is possible if strategies promoting the absence of cross-border mobility, complete protection of transmission abroad, or strict border screening and isolation are implemented. For each strategy, we establish the conditions for the elimination of malaria. We further use our model to identify the control strategies that can help maintain a low endemic level. Our results show that the ideal control strategies should be designed according to the average mosquito biting rates that may depend on the location and season.
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Affiliation(s)
- Ramesh Gautam
- Ratna Rajya Laxmi Campus, Tribhuvan University, KTM, Nepal
| | - Anjana Pokharel
- Padma Kanya Multiple Campus, Tribhuvan University, KTM, Nepal
| | | | | | - Naveen K Vaidya
- Department of Mathematics and Statistics, San Diego State University, San Diego, CA, USA
- Computational Science Research Center, San Diego State University, San Diego, CA, USA
- Viral Information Institute, San Diego State University, San Diego, CA, USA
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13
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Sedda L, McCann RS, Kabaghe AN, Gowelo S, Mburu MM, Tizifa TA, Chipeta MG, van den Berg H, Takken W, van Vugt M, Phiri KS, Cain R, Tangena JAA, Jones CM. Hotspots and super-spreaders: Modelling fine-scale malaria parasite transmission using mosquito flight behaviour. PLoS Pathog 2022; 18:e1010622. [PMID: 35793345 PMCID: PMC9292116 DOI: 10.1371/journal.ppat.1010622] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 07/18/2022] [Accepted: 05/27/2022] [Indexed: 11/19/2022] Open
Abstract
Malaria hotspots have been the focus of public health managers for several years due to the potential elimination gains that can be obtained from targeting them. The identification of hotspots must be accompanied by the description of the overall network of stable and unstable hotspots of malaria, especially in medium and low transmission settings where malaria elimination is targeted. Targeting hotspots with malaria control interventions has, so far, not produced expected benefits. In this work we have employed a mechanistic-stochastic algorithm to identify clusters of super-spreader houses and their related stable hotspots by accounting for mosquito flight capabilities and the spatial configuration of malaria infections at the house level. Our results show that the number of super-spreading houses and hotspots is dependent on the spatial configuration of the villages. In addition, super-spreaders are also associated to house characteristics such as livestock and family composition. We found that most of the transmission is associated with winds between 6pm and 10pm although later hours are also important. Mixed mosquito flight (downwind and upwind both with random components) were the most likely movements causing the spread of malaria in two out of the three study areas. Finally, our algorithm (named MALSWOTS) provided an estimate of the speed of malaria infection progression from house to house which was around 200-400 meters per day, a figure coherent with mark-release-recapture studies of Anopheles dispersion. Cross validation using an out-of-sample procedure showed accurate identification of hotspots. Our findings provide a significant contribution towards the identification and development of optimal tools for efficient and effective spatio-temporal targeted malaria interventions over potential hotspot areas.
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Affiliation(s)
- Luigi Sedda
- Lancaster Ecology and Epidemiology Group, Lancaster Medical School, Lancaster University, United Kingdom
| | - Robert S. McCann
- Laboratory of Entomology, Wageningen University & Research, Wageningen, The Netherlands
- School of Global and Public Health, Kamuzu University of Health Sciences, Blantyre, Malawi
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Alinune N. Kabaghe
- School of Global and Public Health, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Steven Gowelo
- Laboratory of Entomology, Wageningen University & Research, Wageningen, The Netherlands
- School of Global and Public Health, Kamuzu University of Health Sciences, Blantyre, Malawi
- MAC Communicable Diseases Action Centre, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Monicah M. Mburu
- Laboratory of Entomology, Wageningen University & Research, Wageningen, The Netherlands
- School of Global and Public Health, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Tinashe A. Tizifa
- School of Global and Public Health, Kamuzu University of Health Sciences, Blantyre, Malawi
- Center for Tropical Medicine and Travel Medicine, University of Amsterdam, The Netherlands
| | - Michael G. Chipeta
- School of Global and Public Health, Kamuzu University of Health Sciences, Blantyre, Malawi
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Henk van den Berg
- Laboratory of Entomology, Wageningen University & Research, Wageningen, The Netherlands
| | - Willem Takken
- Laboratory of Entomology, Wageningen University & Research, Wageningen, The Netherlands
| | - Michèle van Vugt
- Center for Tropical Medicine and Travel Medicine, University of Amsterdam, The Netherlands
| | - Kamija S. Phiri
- School of Global and Public Health, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Russell Cain
- Lancaster Ecology and Epidemiology Group, Lancaster Medical School, Lancaster University, United Kingdom
| | - Julie-Anne A. Tangena
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Christopher M. Jones
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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14
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A Systematic Review and Meta-Analysis of Malaria Test Positivity Outcomes and Programme Interventions in Low Transmission Settings in Southern Africa, 2000-2021. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19116776. [PMID: 35682356 PMCID: PMC9180605 DOI: 10.3390/ijerph19116776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 04/27/2022] [Accepted: 05/04/2022] [Indexed: 02/01/2023]
Abstract
Malaria is one of the most significant causes of mortality and morbidity globally, especially in sub-Saharan Africa (SSA) countries. It harmfully disturbs the public’s health and the economic growth of many developing countries. Despite the massive effect of malaria transmission, the overall pooled proportion of malaria positivity rate in Southern Africa is still elusive. Therefore, the objective of this systematic review and meta-analysis is to pool estimates of the incidence of the malaria positivity rate, which is the first of its kind in South African countries. A literature search is performed to identify all published articles reporting the incidence of malaria positivity in Southern Africa. Out of the 3359 articles identified, 17 studies meet the inclusion for systematic review and meta-analysis. In addition, because substantial heterogeneity is expected due to the studies being extracted from the universal population, random-effects meta-analyses are carried out to pool the incidence of the malaria positivity rate from diverse diagnostic methods. The result reveals that between-study variability is high (τ2 = 0.003; heterogeneity I2 = 99.91% with heterogeneity chi-square χ2 = 18,143.95, degree of freedom = 16 and a p-value < 0.0001) with the overall random pooled incidence of 10% (95%CI: 8−13%, I2 = 99.91%) in the malaria positivity rate. According to the diagnostic method called pooled incidence estimate, the rapid diagnostic test (RDT) is the leading diagnostic method (17%, 95%CI: 11−24%, I2 = 99.95%), followed by RDT and qPCR and RDT and loop mediated isothermal amplification (LAMP), respectively, found to be (3%, 95%CI: 2−3%, I2 = 0%) and (2%, 95%CI: 1−3%, I2 = 97.94%).Findings of the present study suggest high malaria positive incidence in the region. This implies that malaria control and elimination programmes towards malaria elimination could be negatively impacted and cause delays in actualising malaria elimination set dates. Further studies consisting of larger samples and continuous evaluation of malaria control programmes are recommended.
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15
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Yukich JO, Lindblade K, Kolaczinski J. Receptivity to malaria: meaning and measurement. Malar J 2022; 21:145. [PMID: 35527264 PMCID: PMC9080212 DOI: 10.1186/s12936-022-04155-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 04/07/2022] [Indexed: 01/13/2023] Open
Abstract
"Receptivity" to malaria is a construct developed during the Global Malaria Eradication Programme (GMEP) era. It has been defined in varied ways and no consistent, quantitative definition has emerged over the intervening decades. Despite the lack of consistency in defining this construct, the idea that some areas are more likely to sustain malaria transmission than others has remained important in decision-making in malaria control, planning for malaria elimination and guiding activities during the prevention of re-establishment (POR) period. This manuscript examines current advances in methods of measurement. In the context of a decades long decline in global malaria transmission and an increasing number of countries seeking to eliminate malaria, understanding and measuring malaria receptivity has acquired new relevance.
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Affiliation(s)
- Joshua O. Yukich
- grid.265219.b0000 0001 2217 8588Department of Tropical Medicine, Center for Applied Malaria Research and Evaluation, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA USA
| | - Kim Lindblade
- grid.3575.40000000121633745Global Malaria Programme, World Health Organization, Geneva, CH USA
| | - Jan Kolaczinski
- grid.3575.40000000121633745Global Malaria Programme, World Health Organization, Geneva, CH USA
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Meredith HR, Wesolowski A, Menya D, Esimit D, Lokoel G, Kipkoech J, Freedman B, Lokemer S, Maragia J, Ambani G, Taylor SM, Prudhomme-O’Meara W, Obala AA. Epidemiology of Plasmodium falciparum Infections in a Semi-Arid Rural African Setting: Evidence from Reactive Case Detection in Northwestern Kenya. Am J Trop Med Hyg 2021; 105:1076-1084. [PMID: 34339387 PMCID: PMC8592151 DOI: 10.4269/ajtmh.21-0256] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 05/24/2021] [Indexed: 11/07/2022] Open
Abstract
In northwestern Kenya, Turkana County has been historically considered unsuitable for stable malaria transmission because of its unfavorable climate and predominantly semi-nomadic population; consequently, it is overlooked during malaria control planning. However, the area is changing, with substantial development, an upsurge in travel associated with resource extraction, and more populated settlements forming. Recently, numerous malaria outbreaks have highlighted the need to characterize malaria transmission and its associated risk factors in the region to inform control strategies. Reactive case detection of confirmed malaria cases at six health facilities across central Turkana was conducted from 2018 to 2019. Infections in household members of index cases were detected by malaria rapid diagnostic tests (RDTs) and PCR tests, and they were grouped according household and individual characteristics. The relationships between putative risk factors and infection were quantified by multilevel logistic regression models. Of the 3,189 household members analyzed, 33.6% had positive RDT results and/or PCR test results. RDT-detected infections were more prevalent in children; however, PCR-detected infections were similarly prevalent across age groups. Recent travel was rarely reported and not significantly associated with infection. Bed net coverage was low and net crowding was associated with increased risks of household infections. Infections were present year-round, and fluctuations in prevalence were not associated with rainfall. These findings indicate year-round, endemic transmission with moderate population immunity. This is in stark contrast to recent estimates in this area. Therefore, further investigations to design effective intervention approaches to address malaria in this rapidly changing region and other similar settings across the Horn of Africa are warranted.
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Affiliation(s)
- Hannah R. Meredith
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Amy Wesolowski
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Diana Menya
- Department of Epidemiology and Medical Statistics, School of Public Health, College of Health Sciences, Moi University, Eldoret, Kenya
| | - Daniel Esimit
- Department of Health Services and Sanitation, Turkana County, Kenya
| | - Gilchrist Lokoel
- Department of Health Services and Sanitation, Turkana County, Kenya
| | - Joseph Kipkoech
- Academic Model Providing Access to Healthcare, Eldoret, Kenya
| | - Betsy Freedman
- Division of Infectious Diseases, School of Medicine, Duke University, Durham, North Carolina
| | - Samuel Lokemer
- Department of Health Services and Sanitation, Turkana County, Kenya
| | - James Maragia
- Lodwar County Referral Hospital, Turkana County, Kenya
| | - George Ambani
- Academic Model Providing Access to Healthcare, Eldoret, Kenya
| | - Steve M. Taylor
- Division of Infectious Diseases, School of Medicine, Duke University, Durham, North Carolina
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Wendy Prudhomme-O’Meara
- Department of Epidemiology and Medical Statistics, School of Public Health, College of Health Sciences, Moi University, Eldoret, Kenya
- Division of Infectious Diseases, School of Medicine, Duke University, Durham, North Carolina
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Andrew A. Obala
- School of Medicine, College of Health Sciences, Moi University, Eldoret, Kenya
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Carrel M, Kim S, Mwandagalirwa MK, Mvuama N, Bala JA, Nkalani M, Kihuma G, Atibu J, Diallo AO, Goel V, Thwai KL, Juliano JJ, Emch M, Tshefu A, Parr JB. Individual, household and neighborhood risk factors for malaria in the Democratic Republic of the Congo support new approaches to programmatic intervention. Health Place 2021; 70:102581. [PMID: 34020231 PMCID: PMC8328915 DOI: 10.1016/j.healthplace.2021.102581] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 04/23/2021] [Accepted: 05/04/2021] [Indexed: 11/25/2022]
Abstract
BACKGROUND The Democratic Republic of the Congo (DRC) remains one of the countries most impacted by malaria despite decades of control efforts, including multiple mass insecticide treated net (ITN) distribution campaigns. The multi-scalar and complex nature of malaria necessitates an understanding of malaria risk factors over time and at multiple levels (e.g., individual, household, community). Surveillance of households in both rural and urban settings over time, coupled with detailed behavioral and geographic data, enables the detection of seasonal trends in malaria prevalence and malaria-associated behaviors as well as the assessment of how the local environments within and surrounding an individual's household impact malaria outcomes. METHODS Participants from seven sites in Kinshasa Province, DRC were followed for over two years. Demographic, behavioral, and spatial information was gathered from enrolled households. Malaria was assessed using both rapid diagnostic tests (RDT) and polymerase chain reaction (PCR) and seasonal trends were assessed. Hierarchical regression modeling tested associations between behavioral and environmental factors and positive RDT and PCR outcomes at individual, household and neighborhood scales. RESULTS Among 1591 enrolled participants, malaria prevalence did not consistently vary seasonally across the sites but did vary by age and ITN usage. Malaria was highest and ITN usage lowest in children ages 6-15 years across study visits and seasons. Having another member of the household test positive for malaria significantly increased the risk of an individual having malaria [RDT: OR = 4.158 (2.86-6.05); PCR: OR = 3.37 (2.41-4.71)], as did higher malaria prevalence in the 250 m neighborhood around the household [RDT: OR = 2.711 (1.42-5.17); PCR: OR = 4.056 (2.3-7.16)]. Presence of water within close proximity to the household was also associated with malaria outcomes. CONCLUSIONS Taken together, these findings suggest that targeting non-traditional age groups, children >5 years old and teenagers, and deploying household- and neighborhood-focused interventions may be effective strategies for improving malaria outcomes in high-burden countries like the DRC.
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Affiliation(s)
- Margaret Carrel
- Department of Geographical & Sustainability Sciences, 305 Jessup Hall, University of Iowa, Iowa City, IA, 52245, USA.
| | - Seungwon Kim
- Department of Geographical & Sustainability Sciences, 305 Jessup Hall, University of Iowa, Iowa City, IA, 52245, USA.
| | - Melchior Kashamuka Mwandagalirwa
- Department of Epidemiology, CB7435, McGavran-Greenberg Hall, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA; Ecole de Sante Publique, Faculte de Medecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo, USA.
| | - Nono Mvuama
- Ecole de Sante Publique, Faculte de Medecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo, USA.
| | - Joseph A Bala
- Ecole de Sante Publique, Faculte de Medecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo, USA.
| | - Marthe Nkalani
- Ecole de Sante Publique, Faculte de Medecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo, USA.
| | - Georges Kihuma
- Ecole de Sante Publique, Faculte de Medecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo, USA.
| | - Joseph Atibu
- Ecole de Sante Publique, Faculte de Medecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo, USA.
| | - Alpha Oumar Diallo
- Department of Epidemiology, CB7435, McGavran-Greenberg Hall, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA.
| | - Varun Goel
- Department of Geography, CB3220, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA.
| | - Kyaw L Thwai
- Department of Epidemiology, CB7435, McGavran-Greenberg Hall, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA.
| | - Jonathan J Juliano
- Department of Epidemiology, CB7435, McGavran-Greenberg Hall, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA; Division of Infectious Diseases, School of Medicine, CB#7030, 130 Mason Farm Road, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA.
| | - Michael Emch
- Department of Geography, CB3220, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA.
| | - Antoinette Tshefu
- Ecole de Sante Publique, Faculte de Medecine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo, USA.
| | - Jonathan B Parr
- Division of Infectious Diseases, School of Medicine, CB#7030, 130 Mason Farm Road, University of North Carolina-Chapel Hill, Chapel Hill, NC, 27599, USA.
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Smith JL, Mumbengegwi D, Haindongo E, Cueto C, Roberts KW, Gosling R, Uusiku P, Kleinschmidt I, Bennett A, Sturrock HJ. Malaria risk factors in northern Namibia: The importance of occupation, age and mobility in characterizing high-risk populations. PLoS One 2021; 16:e0252690. [PMID: 34170917 PMCID: PMC8232432 DOI: 10.1371/journal.pone.0252690] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 05/20/2021] [Indexed: 11/19/2022] Open
Abstract
In areas of low and unstable transmission, malaria cases occur in populations with lower access to malaria services and interventions, and in groups with specific malaria risk exposures often away from the household. In support of the Namibian National Vector Borne Disease Program's drive to better target interventions based upon risk, we implemented a health facility-based case control study aimed to identify risk factors for symptomatic malaria in Zambezi Region, northern Namibia. A total of 770 febrile individuals reporting to 6 health facilities and testing positive by rapid diagnostic test (RDT) between February 2015 and April 2016 were recruited as cases; 641 febrile individuals testing negative by RDT at the same health facilities through June 2016 were recruited as controls. Data on socio-demographics, housing construction, overnight travel, use of malaria prevention and outdoor behaviors at night were collected through interview and recorded on a tablet-based questionnaire. Remotely-sensed environmental data were extracted for geo-located village residence locations. Multivariable logistic regression was conducted to identify risk factors and latent class analyses (LCA) used to identify and characterize high-risk subgroups. The majority of participants (87% of cases and 69% of controls) were recruited during the 2016 transmission season, an outbreak year in Southern Africa. After adjustment, cases were more likely to be cattle herders (Adjusted Odds Ratio (aOR): 4.46 95%CI 1.05-18.96), members of the police or other security personnel (aOR: 4.60 95%CI: 1.16-18.16), and pensioners/unemployed persons (aOR: 2.25 95%CI 1.24-4.08), compared to agricultural workers (most common category). Children (aOR 2.28 95%CI 1.13-4.59) and self-identified students were at higher risk of malaria (aOR: 4.32 95%CI 2.31-8.10). Other actionable risk factors for malaria included housing and behavioral characteristics, including traditional home construction and sleeping in an open structure (versus modern structure: aOR: 2.01 95%CI 1.45-2.79 and aOR: 4.76 95%CI: 2.14-10.57); cross border travel in the prior 30 days (aOR: 10.55 95%CI 2.94-37.84); and outdoor agricultural work at night (aOR: 2.09 95%CI 1.12-3.87). Malaria preventive activities were all protective and included personal use of an insecticide treated net (ITN) (aOR: 0.61 95%CI 0.42-0.87), adequate household ITN coverage (aOR: 0.63 95%CI 0.42-0.94), and household indoor residual spraying (IRS) in the past year (versus never sprayed: (aOR: 0.63 95%CI 0.44-0.90). A number of environmental factors were associated with increased risk of malaria, including lower temperatures, higher rainfall and increased vegetation for the 30 days prior to diagnosis and residing more than 5 minutes from a health facility. LCA identified six classes of cases, with class membership strongly correlated with occupation, age and select behavioral risk factors. Use of ITNs and IRS coverage was similarly low across classes. For malaria elimination these high-risk groups will need targeted and tailored intervention strategies, for example, by implementing alternative delivery methods of interventions through schools and worksites, as well as the use of specific interventions that address outdoor transmission.
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Affiliation(s)
- Jennifer L. Smith
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco (UCSF), San Francisco, California, United States of America
| | - Davis Mumbengegwi
- Multidisciplinary Research Centre, University of Namibia, Windhoek, Namibia
| | - Erastus Haindongo
- School of Medicine, Faculty of Health Sciences, University of Namibia, Windhoek, Namibia
| | - Carmen Cueto
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco (UCSF), San Francisco, California, United States of America
| | - Kathryn W. Roberts
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco (UCSF), San Francisco, California, United States of America
| | - Roly Gosling
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco (UCSF), San Francisco, California, United States of America
| | - Petrina Uusiku
- National Ministry of Health and Social Services, Windhoek, Namibia
| | - Immo Kleinschmidt
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Adam Bennett
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco (UCSF), San Francisco, California, United States of America
| | - Hugh J. Sturrock
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco (UCSF), San Francisco, California, United States of America
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Okebe J, Dabira E, Jaiteh F, Mohammed N, Bradley J, Drammeh NF, Bah A, Masunaga Y, Achan J, Muela Ribera J, Yeung S, Balen J, Peeters Grietens K, D'Alessandro U. Reactive, self-administered malaria treatment against asymptomatic malaria infection: results of a cluster randomized controlled trial in The Gambia. Malar J 2021; 20:253. [PMID: 34098984 PMCID: PMC8186162 DOI: 10.1186/s12936-021-03761-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 05/11/2021] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND Selectively targeting and treating malaria-infected individuals may further decrease parasite carriage in low-burden settings. Using a trans-disciplinary approach, a reactive treatment strategy to reduce Plasmodium falciparum prevalence in participating communities was co-developed and tested. METHODS This is a 2-arm, open-label, cluster-randomized trial involving villages in Central Gambia during the 2017 and 2018 malaria transmission season. Villages were randomized in a 1:1 ratio using a minimizing algorithm. In the intervention arm, trained village health workers delivered a full course of pre-packed dihydroartemisinin-piperaquine to all residents of compounds where clinical cases were reported while in the control arm, compound residents were screened for infection at the time of the index case reporting. All index cases were treated following national guidelines. The primary endpoint was malaria prevalence, determined by molecular methods, at the end of the intervention period. RESULTS The trial was carried out in 50 villages: 34 in 2017 and 16 additional villages in 2018. At the end of the 2018 transmission season, malaria prevalence was 0.8% (16/1924, range 0-4%) and 1.1% (20/1814, range 0-17%) in the intervention and control arms, respectively. The odds of malaria infection were 29% lower in the intervention than in the control arm after adjustment for age (OR 0.71, 95% CI 0.27-1.84, p = 0.48). Adherence to treatment was high, with 98% (964/979) of those treated completing the 3-day treatment. Over the course of the study, only 37 villages, 20 in the intervention and 17 in the control arm, reported at least one clinical case. The distribution of clinical cases by month in both transmission seasons was similar and the odds of new clinical malaria cases during the trial period did not vary between arms (OR 1.04, 95% CI 0.57-1.91, p = 0.893). All adverse events were classified as mild to moderate and resolved completely. CONCLUSION The systematic and timely administration of an anti-malarial treatment to residents of compounds with confirmed malaria cases did not significantly decrease malaria prevalence and incidence in communities where malaria prevalence was already low. Treatment coverage and adherence was very high. Results were strongly influenced by the lower-than-expected malaria prevalence, and by no clinical cases in villages with asymptomatic malaria-infected individuals. TRIAL REGISTRATION This study is registered with ClinicalTrials.gov, NCT02878200. Registered 25 August 2016. https://clinicaltrials.gov/ct2/show/NCT02878200 .
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Affiliation(s)
- Joseph Okebe
- Medical Research Council Unit The Gambia At the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Edgard Dabira
- Medical Research Council Unit The Gambia At the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Fatou Jaiteh
- Medical Anthropology Unit, Institute of Tropical Medicine, Antwerp, Belgium
- Amsterdam Institute of Social Science Research, Amsterdam, The Netherlands
| | - Nuredin Mohammed
- Medical Research Council Unit The Gambia At the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - John Bradley
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| | - Ndey-Fatou Drammeh
- Medical Research Council Unit The Gambia At the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Amadou Bah
- Medical Research Council Unit The Gambia At the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Yoriko Masunaga
- Medical Anthropology Unit, Institute of Tropical Medicine, Antwerp, Belgium
- Amsterdam Institute of Social Science Research, Amsterdam, The Netherlands
| | - Jane Achan
- Medical Research Council Unit The Gambia At the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
- Malaria Consortium, Cambridge Heath, London, UK
| | | | - Shunmay Yeung
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
| | - Julie Balen
- School of Health and Related Research, The University of Sheffield, Sheffield, UK
| | | | - Umberto D'Alessandro
- Medical Research Council Unit The Gambia At the London School of Hygiene and Tropical Medicine, Fajara, The Gambia.
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Moore C, Scherr T, Matoba J, Sing'anga C, Lubinda M, Thuma P, Wright D. mHAT app for automated malaria rapid test result analysis and aggregation: a pilot study. Malar J 2021; 20:237. [PMID: 34039358 PMCID: PMC8153521 DOI: 10.1186/s12936-021-03772-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 05/16/2021] [Indexed: 12/29/2022] Open
Abstract
Background There are a variety of approaches being used for malaria surveillance. While active and reactive case detection have been successful in localized areas of low transmission, concerns over scalability and sustainability keep the approaches from being widely accepted. Mobile health interventions are poised to address these shortcomings by automating and standardizing portions of the surveillance process. In this study, common challenges associated with current data aggregation methods have been quantified, and a web-based mobile phone application is presented to reduce the burden of reporting rapid diagnostic test (RDT) results in low-resource settings. Methods De-identified completed RDTs were collected at 14 rural health clinics as part of a malaria epidemiology study at Macha Research Trust, Macha, Zambia. Tests were imaged using the mHAT web application. Signal intensity was measured and a binary result was provided. App performance was validated by: (1) comparative limits of detection, investigated against currently used laboratory lateral flow assay readers; and, (2) receiver operating characteristic analysis comparing the application against visual inspection of RDTs by an expert. Secondary investigations included analysis of time-to-aggregation and data consistency within the existing surveillance structures established by Macha Research Trust. Results When compared to visual analysis, the mHAT app performed with 91.9% sensitivity (CI 78.7, 97.2) and specificity was 91.4% (CI 77.6, 97.0) regardless of device operating system. Additionally, an analysis of surveillance data from January 2017 through mid-February 2019 showed that while the majority of the data packets from satellite clinics contained correct data, 36% of data points required correction by verification teams. Between November 2018 and mid-February 2019, it was also found that 44.8% of data was received after the expected submission date, although most (65.1%) reports were received within 2 days. Conclusions Overall, the mHAT mobile app was observed to be sensitive and specific when compared to both currently available benchtop lateral flow readers and visual inspection. The additional benefit of automating and standardizing LFA data collection and aggregation poses a vital improvement for low-resource health facilities and could increase the accuracy and speed of data reporting in surveillance campaigns. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03772-5.
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Affiliation(s)
- Carson Moore
- Department of Chemistry, Vanderbilt University, 1234 Stevenson Center Lane, Nashville, TN, 37212, USA
| | - Thomas Scherr
- Department of Chemistry, Vanderbilt University, 1234 Stevenson Center Lane, Nashville, TN, 37212, USA.
| | | | | | | | - Phil Thuma
- Macha Research Trust, Choma District, Zambia
| | - David Wright
- Department of Chemistry, Vanderbilt University, 1234 Stevenson Center Lane, Nashville, TN, 37212, USA
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21
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Jaiteh F, Ribera JM, Masunaga Y, Okebe J, D'Alessandro U, Balen J, Achan J, Gerrets R, Peeters Grietens K. Complexities in Defining the Unit of Intervention for Reactive Community-Based Malaria Treatment in the Gambia. Front Public Health 2021; 9:601152. [PMID: 33718317 PMCID: PMC7952428 DOI: 10.3389/fpubh.2021.601152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 02/02/2021] [Indexed: 11/24/2022] Open
Abstract
With significant declines in malaria, infections are increasingly clustered in households, or groups of households where malaria transmission is higher than in surrounding household/villages. To decrease transmission in such cases, reactive interventions target household members of clinical malaria cases, with the intervention unit (e.g., the "household/s") derived from an epidemiological and operational perspective. A lack of unanimity regarding the spatial range of the intervention unit calls for greater importance to be placed on social context in conceptualizing the appropriate unit. A novel malaria elimination strategy based on reactive treatment was recently evaluated by a cluster randomized trial in a low transmission setting in The Gambia. Transdisciplinary research was used to assess and improve the effectiveness of the intervention which consisted, among others, of reflecting on whether the household was the most adequate unit of analysis. The intervention was piloted on the smallest treatment unit possible and was further adapted following a better understanding of the social and epidemiological context. Intervention units defined according to (i) shared sleeping spaces and (ii) household membership, showed substantial limitations as it was not possible to define them clearly and they were extremely variable within the study setting. Incorporating local definitions and community preference in the trial design led to the appropriate intervention unit-the compound-defined as an enclosed space containing one or several households belonging to the same extended patrilineal family. Our study demonstrates the appropriateness of using transdisciplinary research for investigating alternative intervention units that are better tailored to reactive treatment approaches.
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Affiliation(s)
- Fatou Jaiteh
- Medical Research Council Unit the Gambia at the London School of Hygiene and Tropical Medicine, Banjul, Gambia
- Medical Anthropology Unit, Institute of Tropical Medicine, Antwerp, Belgium
- Faculty of Social and Behavioural Sciences, Amsterdam Institute of Social Science Research, Amsterdam, Netherlands
| | | | - Yoriko Masunaga
- Medical Anthropology Unit, Institute of Tropical Medicine, Antwerp, Belgium
- Faculty of Social and Behavioural Sciences, Amsterdam Institute of Social Science Research, Amsterdam, Netherlands
| | - Joseph Okebe
- Medical Research Council Unit the Gambia at the London School of Hygiene and Tropical Medicine, Banjul, Gambia
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Umberto D'Alessandro
- Medical Research Council Unit the Gambia at the London School of Hygiene and Tropical Medicine, Banjul, Gambia
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Julie Balen
- School of Health and Related Research (ScHARR), The University of Sheffield, Sheffield, United Kingdom
| | - Jane Achan
- Medical Research Council Unit the Gambia at the London School of Hygiene and Tropical Medicine, Banjul, Gambia
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Rene Gerrets
- Faculty of Social and Behavioural Sciences, Amsterdam Institute of Social Science Research, Amsterdam, Netherlands
| | - Koen Peeters Grietens
- Medical Anthropology Unit, Institute of Tropical Medicine, Antwerp, Belgium
- PASS Suisse, Neuchâtel, Switzerland
- School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
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22
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Jaiteh F, Okebe J, Masunaga Y, D'Alessandro U, Achan J, Gryseels C, de Vries D, Ribera JM, Grietens KP. Understanding adherence to reactive treatment of asymptomatic malaria infections in The Gambia. Sci Rep 2021; 11:1746. [PMID: 33462329 PMCID: PMC7813830 DOI: 10.1038/s41598-021-81468-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 12/18/2020] [Indexed: 11/29/2022] Open
Abstract
The impact of different types of reactive case detection and/or treatment strategies for malaria elimination depends on high coverage and participants’ adherence. However, strategies to optimise adherence are limited, particularly for people with asymptomatic or no infections. As part of a cluster-randomized trial to evaluate the effect of reactive treatment in The Gambia, all residents in the compound of a diagnosed clinical malaria patient received dihydro-artemisinin–piperaquine (DP). Using a mixed method approach, we assessed which factors contribute to adherence among the contacts of malaria cases that showed no symptoms. Adherence was defined as the proportion of compound members that (1) returned all medicine bags empty and (2) self-reported (3-day) treatment completion. Among the 273 individuals from 14 compounds who received DP, 227 (83.1%) were available for and willing to participate in the survey; 85.3% (233/273) returned empty medicine bags and 91.6% (208/227) self-reported treatment completion. Although clinical malaria was not considered a major health problem, reported adherence was high. The drivers of adherence were the strong sense of responsibility towards protecting the individual, compound and the village. Adherence can be optimised through a transdisciplinary implementation research process of engaging communities to bridge the gap between research goals and social realities.
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Affiliation(s)
- Fatou Jaiteh
- Medical Research Council Unit the Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia. .,Medical Anthropology Unit, Institute of Tropical Medicine, Antwerp, Belgium. .,Amsterdam Institute of Social Science Research, Amsterdam, The Netherlands.
| | - Joseph Okebe
- Medical Research Council Unit the Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia.,Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Yoriko Masunaga
- Medical Anthropology Unit, Institute of Tropical Medicine, Antwerp, Belgium.,Amsterdam Institute of Social Science Research, Amsterdam, The Netherlands
| | - Umberto D'Alessandro
- Medical Research Council Unit the Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Jane Achan
- Medical Research Council Unit the Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Charlotte Gryseels
- Medical Anthropology Unit, Institute of Tropical Medicine, Antwerp, Belgium
| | - Daniel de Vries
- Amsterdam Institute of Social Science Research, Amsterdam, The Netherlands
| | | | - Koen Peeters Grietens
- Medical Anthropology Unit, Institute of Tropical Medicine, Antwerp, Belgium.,PASS Suisse, Neuchâtel, Switzerland.,School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
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23
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Hsiang MS, Ntshalintshali N, Kang Dufour MS, Dlamini N, Nhlabathi N, Vilakati S, Malambe C, Zulu Z, Maphalala G, Novotny J, Murphy M, Schwartz A, Sturrock H, Gosling R, Dorsey G, Kunene S, Greenhouse B. Active Case Finding for Malaria: A 3-Year National Evaluation of Optimal Approaches to Detect Infections and Hotspots Through Reactive Case Detection in the Low-transmission Setting of Eswatini. Clin Infect Dis 2021; 70:1316-1325. [PMID: 31095677 PMCID: PMC7318780 DOI: 10.1093/cid/ciz403] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Accepted: 05/15/2019] [Indexed: 11/15/2022] Open
Abstract
Background Reactive case detection (RACD) is a widely practiced malaria elimination intervention whereby close contacts of index cases receive malaria testing to inform treatment and other interventions. However, the optimal diagnostic and operational approaches for this resource-intensive strategy are not clear. Methods We conducted a 3-year prospective national evaluation of RACD in Eswatini, a malaria elimination setting. Loop-mediated isothermal amplification (LAMP) was compared to traditional rapid diagnostic testing (RDT) for the improved detection of infections and for hotspots (RACD events yielding ≥1 additional infection). The potential for index case–, RACD-, and individual-level factors to improve efficiencies was also evaluated. Results Among 377 RACD events, 10 890 participants residing within 500 m of index cases were tested. Compared to RDT, LAMP provided a 3-fold and 2.3-fold higher yield to detect infections (1.7% vs 0.6%) and hotspots (29.7% vs 12.7%), respectively. Hotspot detection improved with ≥80% target population coverage and response times within 7 days. Proximity to the index case was associated with a dose-dependent increased infection risk (up to 4-fold). Individual-, index case–, and other RACD-level factors were considered but the simple approach of restricting RACD to a 200-m radius maximized yield and efficiency. Conclusions We present the first large-scale national evaluation of optimal RACD approaches from a malaria elimination setting. To inform delivery of antimalarial drugs or other interventions, RACD, when conducted, should utilize more sensitive diagnostics and clear context-specific operational parameters. Future studies of RACD’s impact on transmission may still be needed.
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Affiliation(s)
- Michelle S Hsiang
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas.,Malaria Elimination Initiative, Global Health Group.,Department of Pediatrics, University of California, San Francisco (UCSF)
| | | | | | | | | | | | | | | | | | - Joseph Novotny
- Clinton Health Access Initiative, Eswatini Office, Mbabane
| | - Maxwell Murphy
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, UCSF
| | - Alanna Schwartz
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, UCSF
| | | | - Roly Gosling
- Malaria Elimination Initiative, Global Health Group
| | - Grant Dorsey
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, UCSF
| | | | - Bryan Greenhouse
- Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, UCSF
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24
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Nasir SMI, Amarasekara S, Wickremasinghe R, Fernando D, Udagama P. Prevention of re-establishment of malaria: historical perspective and future prospects. Malar J 2020; 19:452. [PMID: 33287809 PMCID: PMC7720033 DOI: 10.1186/s12936-020-03527-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 11/26/2020] [Indexed: 12/17/2022] Open
Abstract
Prevention of re-establishment (POR) refers to the prevention of malaria outbreak/epidemic occurrence or preventing re-establishment of indigenous malaria in a malaria-free country. Understanding the effectiveness of the various strategies used for POR is, therefore, of vital importance to countries certified as "malaria-free" or to the countries to be thus certified in the near future. This review is based on extensive review of literature on both the POR strategies and elimination schemes of countries, (i) that have reached malaria-free status (e.g. Armenia, Mauritius, Sri Lanka), (ii) those that are reaching pre-elimination stage (e.g. South Korea), and (iii) countries at the control phase (e.g. India). History has clearly shown that poorly implemented POR programmes can result in deadly consequences (e.g. Sri Lanka); conversely, there are examples of robust POR programmes that have sustained malaria free status that can serve as examples to countries working toward elimination. Countries awaiting malaria elimination status should pre-plan their POR strategies. Malaria-free countries face the risk of resurgence mostly due to imported malaria cases; thus, a robust passenger screening programme and cross border collaborations are crucial in a POR setting. In addition, sustained vigilance, and continued funding for the national anti-malarial campaign programme and for related research is of vital importance for POR. With distinct intrinsic potential for malaria in each country, tailor-made POR programmes are built through continuous and robust epidemiological and entomological surveillance, particularly in countries such as Sri Lanka with increased receptivity and vulnerability for malaria transmission. In summary, across all five countries under scrutiny, common strengths of the POR programmes are (i) a multipronged approach, (ii) strong passive, active, and activated passive case detection, (iii) Indoor residual spraying (IRS), and (iv) health education/awareness programmes.
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Affiliation(s)
- S M Ibraheem Nasir
- Department of Zoology & Environment Sciences, Faculty of Science, University of Colombo, Colombo 3, Sri Lanka
| | - Sachini Amarasekara
- Department of Zoology & Environment Sciences, Faculty of Science, University of Colombo, Colombo 3, Sri Lanka
| | - Renu Wickremasinghe
- Department of Parasitology, Faculty of Medical Sciences, University of Sri Jayewardenepura, Nugegoda, Sri Lanka
| | - Deepika Fernando
- Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo 8, Sri Lanka
| | - Preethi Udagama
- Department of Zoology & Environment Sciences, Faculty of Science, University of Colombo, Colombo 3, Sri Lanka.
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25
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Ekawati LL, Johnson KC, Jacobson JO, Cueto CA, Zarlinda I, Elyazar IRF, Fatah A, Sumiwi ME, Noviyanti R, Cotter C, Smith JL, Coutrier FN, Bennett A. Defining malaria risks among forest workers in Aceh, Indonesia: a formative assessment. Malar J 2020; 19:441. [PMID: 33256743 PMCID: PMC7708119 DOI: 10.1186/s12936-020-03511-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 11/19/2020] [Indexed: 12/02/2022] Open
Abstract
Background Following a dramatic decline of malaria cases in Aceh province, geographically-based reactive case detection (RACD) was recently evaluated as a tool to improve surveillance with the goal of malaria elimination. While RACD detected few cases in households surrounding index cases, engaging in forest work was identified as a risk factor for malaria and infections from Plasmodium knowlesi—a non-human primate malaria parasite—were more common than expected. This qualitative formative assessment was conducted to improve understanding of malaria risk from forest work and identify strategies for targeted surveillance among forest workers, including adapting reactive case detection. Methods Between June and August, 2016, five focus groups and 18 in-depth interviews with forest workers and key informants were conducted in each of four subdistricts in Aceh Besar and Aceh Jaya districts. Themes included: types of forest activities, mobility of workers, interactions with non-human primates, malaria prevention and treatment-seeking behaviours, and willingness to participate in malaria surveys at forest work sites and using peer-referral. Results Reported forest activities included mining, logging, and agriculture in the deep forest and along the forest fringe. Forest workers, particularly miners and loggers, described often spending weeks to months at work sites in makeshift housing, rarely utilizing mosquito prevention and, upon fever, self-medicating and seeking care from traditional healers or pharmacies rather than health facilities. Non-human primates are frequently observed near work sites, and most forest work locations are within a day’s journey of health clinics. Employers and workers expressed interest in undertaking malaria testing and in participating in survey recruitment by peer-referral and at work sites. Conclusions Diverse groups of forest workers in Aceh are potentially exposed to malaria through forest work. Passive surveillance and household-based screening may under-estimate malaria burden due to extended stays in the forest and health-seeking behaviours. Adapting active surveillance to specifically target forest workers through work-site screening and/or peer-referral appears promising for addressing currently undetected infections.
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Affiliation(s)
- Lenny L Ekawati
- Eijkman-Oxford Clinical Research Unit, Eijkman Institute for Molecular Biology, Jalan Diponegoro No. 69, Jakarta, 10430, Indonesia.
| | | | - Jerry O Jacobson
- Malaria Elimination Initiative, Global Health Group, University of California San Fransisco (UCSF), San Fransisco, CA, 94158, USA
| | - Carmen A Cueto
- Malaria Elimination Initiative, Global Health Group, University of California San Fransisco (UCSF), San Fransisco, CA, 94158, USA
| | - Iska Zarlinda
- Malaria Pathogenesis Unit, Eijkman Institute for Molecular Biology, Jalan Diponegoro No. 69, Jakarta, 10430, Indonesia
| | - Iqbal R F Elyazar
- Eijkman-Oxford Clinical Research Unit, Eijkman Institute for Molecular Biology, Jalan Diponegoro No. 69, Jakarta, 10430, Indonesia
| | - Abdul Fatah
- Aceh Provincial Health Office, Jalan Teungku Syech Mudawali No 6, Kota Banda Aceh, Aceh, 23116, Indonesia
| | - Maria E Sumiwi
- United Nation Children's Fund Indonesia, Jalan Jendral Sudirman Kavling 31, Jakarta, 12920, Indonesia
| | - Rintis Noviyanti
- Malaria Pathogenesis Unit, Eijkman Institute for Molecular Biology, Jalan Diponegoro No. 69, Jakarta, 10430, Indonesia
| | - Chris Cotter
- Malaria Elimination Initiative, Global Health Group, University of California San Fransisco (UCSF), San Fransisco, CA, 94158, USA
| | - Jennifer L Smith
- Malaria Elimination Initiative, Global Health Group, University of California San Fransisco (UCSF), San Fransisco, CA, 94158, USA
| | - Farah N Coutrier
- Malaria Pathogenesis Unit, Eijkman Institute for Molecular Biology, Jalan Diponegoro No. 69, Jakarta, 10430, Indonesia
| | - Adam Bennett
- Malaria Elimination Initiative, Global Health Group, University of California San Fransisco (UCSF), San Fransisco, CA, 94158, USA
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26
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Searle KM, Katowa B, Musonda M, Pringle JC, Hamapumbu H, Matoba J, Lubinda M, Shields T, Kobayashi T, Stevenson JC, Norris DE, Thuma PE, Wesolowski A, Moss WJ, For The Southern And Central Africa International Center Of Excellence For Malaria Research. Sustained Malaria Transmission despite Reactive Screen-and-Treat in a Low-Transmission Area of Southern Zambia. Am J Trop Med Hyg 2020; 104:671-679. [PMID: 33236715 PMCID: PMC7866307 DOI: 10.4269/ajtmh.20-0947] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 09/28/2020] [Indexed: 12/30/2022] Open
Abstract
Malaria elimination strategies are designed to more effectively identify and treat infected individuals to interrupt transmission. One strategy, reactive screen-and-treat, starts with passive detection of symptomatic cases at health facilities. Individuals residing within the index case and neighboring households are screened with a malaria rapid diagnostic test (RDT) and treated if positive. However, it is unclear to what extent this strategy is effective in reducing transmission. Reactive screen-and-treat was implemented in Choma district, Southern Province, Zambia, in 2013, in which residents of the index case and neighboring households within 140 m were screened with an RDT. From March 2016 to July 2018, the screening radius was extended to 250-m, and additional follow-up visits at 30 and 90 days were added to evaluate the strategy. Plasmodium falciparum parasite prevalence was measured using an RDT and by quantitative PCR (qPCR). A 24-single nucleotide polymorphism molecular bar-code assay was used to genotype parasites. Eighty-four index case households with 676 residents were enrolled between March 2016 and March 2018. Within each season, parasite prevalence declined significantly in index households at the 30-day visit and remained low at the 90-day visit. However, parasite prevalence was not reduced to zero. Infections identified by qPCR persisted between study visits and were not identified by RDT. Parasites identified within the same household were most genetically related; however, overall parasite relatedness was low and similar across time and space. Thus, despite implementation of a reactive screen-and-treat program, parasitemia was not eliminated, and persisted in targeted households for at least 3 months.
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Affiliation(s)
- Kelly M Searle
- Division of Epidemiology and Community Health, University of Minnesota School of Public Health, Minneapolis, Minnesota
| | | | | | - Julia C Pringle
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | | | | | - Timothy Shields
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Tamaki Kobayashi
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Jennifer C Stevenson
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.,Macha Research Trust, Macha, Zambia
| | - Douglas E Norris
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Philip E Thuma
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.,Macha Research Trust, Macha, Zambia
| | - Amy Wesolowski
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - William J Moss
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.,W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
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27
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Spatial and genetic clustering of Plasmodium falciparum and Plasmodium vivax infections in a low-transmission area of Ethiopia. Sci Rep 2020; 10:19975. [PMID: 33203956 PMCID: PMC7672087 DOI: 10.1038/s41598-020-77031-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 11/02/2020] [Indexed: 11/23/2022] Open
Abstract
The distribution of malaria infections is heterogeneous in space and time, especially in low transmission settings. Understanding this clustering may allow identification and targeting of pockets of transmission. In Adama district, Ethiopia, Plasmodium falciparum and P. vivax malaria patients and controls were examined, together with household members and immediate neighbors. Rapid diagnostic test and quantitative PCR (qPCR) were used for the detection of infections that were genetically characterized by a panel of microsatellite loci for P. falciparum (26) and P. vivax (11), respectively. Individuals living in households of clinical P. falciparum patients were more likely to have qPCR detected P. falciparum infections (22.0%, 9/41) compared to individuals in control households (8.7%, 37/426; odds ratio, 2.9; 95% confidence interval, 1.3–6.4; P = .007). Genetically related P. falciparum, but not P. vivax infections showed strong clustering within households. Genotyping revealed a marked temporal cluster of P. falciparum infections, almost exclusively comprised of clinical cases. These findings uncover previously unappreciated transmission dynamics and support a rational approach to reactive case detection strategies for P. falciparum in Ethiopia.
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28
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Perera R, Caldera A, Wickremasinghe AR. Reactive Case Detection (RACD) and foci investigation strategies in malaria control and elimination: a review. Malar J 2020; 19:401. [PMID: 33172462 PMCID: PMC7653886 DOI: 10.1186/s12936-020-03478-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 11/02/2020] [Indexed: 11/30/2022] Open
Abstract
Background Reactive case detection (RACD) and foci investigation are key strategies in malaria elimination and prevention of its re-establishment. They are a key part of surveillance that has been recommended by the World Health Organization (WHO) to be considered as a core intervention and as one of the three pillars of the Global Technical Strategy for Malaria 2016–2030. Methods A search using the key words “Reactive Case Detection”, “RACD”, “RCD” and “Malaria” was carried out in PubMed, Scopus, Taylor and Francis online databases for studies published until 31st July 2019. The inclusion criteria for selection of articles for review included (1) how RACD is implemented in each country; (2) challenges faced in RACD implementation; (3) suggestions on how the effectiveness of RACD process can be improved. Results 411 titles were identified, 41 full text articles were screened and 29 were found eligible for inclusion in the review. Published literature on RACD, and case and foci investigations has mostly assessed the process of the activity. Most studies have documented that the yield of positives in RACD has been highest in the index case’s household and the immediate neighbourhood of the index case. Microscopy and RDTs are the common tests used in RACD. The guidelines for case and foci investigation, and RACD and PACD, are not universally adopted and are country-specific. Some of the limitations and challenges identified include lack of proper guidelines, logistic issues and problems with public compliance. Conclusions Although there is no documented evidence that RACD is useful in malaria elimination settings, most authors have opined that RACD is necessary for malaria elimination. Lack of knowledge in the target populations, a target radius and how to carry out the RACD process is a major challenge in the decision-making process.
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Affiliation(s)
- Ruwanthi Perera
- Department of Public Health, Faculty of Medicine, University of Kelaniya, P. O. Box 6, Thalagolla Road, Ragama, 11010, Sri Lanka
| | - Amandhi Caldera
- Department of Public Health, Faculty of Medicine, University of Kelaniya, P. O. Box 6, Thalagolla Road, Ragama, 11010, Sri Lanka
| | - A Rajitha Wickremasinghe
- Department of Public Health, Faculty of Medicine, University of Kelaniya, P. O. Box 6, Thalagolla Road, Ragama, 11010, Sri Lanka.
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29
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Stresman G, Whittaker C, Slater HC, Bousema T, Cook J. Quantifying Plasmodium falciparum infections clustering within households to inform household-based intervention strategies for malaria control programs: An observational study and meta-analysis from 41 malaria-endemic countries. PLoS Med 2020; 17:e1003370. [PMID: 33119589 PMCID: PMC7595326 DOI: 10.1371/journal.pmed.1003370] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 09/11/2020] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Reactive malaria strategies are predicated on the assumption that individuals infected with malaria are clustered within households or neighbourhoods. Despite the widespread programmatic implementation of reactive strategies, little empirical evidence exists as to whether such strategies are appropriate and, if so, how they should be most effectively implemented. METHODS AND FINDINGS We collated 2 different datasets to assess clustering of malaria infections within households: (i) demographic health survey (DHS) data, integrating household information and patent malaria infection, recent fever, and recent treatment status in children; and (ii) data from cross-sectional and reactive detection studies containing information on the household and malaria infection status (patent and subpatent) of all-aged individuals. Both datasets were used to assess the odds of infections clustering within index households, where index households were defined based on whether they contained infections detectable through one of 3 programmatic strategies: (a) Reactive Case Detection (RACD) classifed by confirmed clinical cases, (b) Mass Screen and Treat (MSAT) classifed by febrile, symptomatic infections, and (c) Mass Test and Treat (MTAT) classifed by infections detectable using routine diagnostics. Data included 59,050 infections in 208,140 children under 7 years old (median age = 2 years, minimum = 2, maximum = 7) by microscopy/rapid diagnostic test (RDT) from 57 DHSs conducted between November 2006 and December 2018 from 23 African countries. Data representing 11,349 infections across all ages (median age = 22 years, minimum = 0.5, maximum = 100) detected by molecular tools in 132,590 individuals in 43 studies published between April 2006 and May 2019 in 20 African, American, Asian, and Middle Eastern countries were obtained from the published literature. Extensive clustering was observed-overall, there was a 20.40 greater (95% credible interval [CrI] 0.35-20.45; P < 0.001) odds of patent infections (according to the DHS data) and 5.13 greater odds (95% CI 3.85-6.84; P < 0.001) of molecularly detected infections (from the published literature) detected within households in which a programmatically detectable infection resides. The strongest degree of clustering identified by polymerase chain reaction (PCR)/ loop mediated isothermal amplification (LAMP) was observed using the MTAT strategy (odds ratio [OR] = 6.79, 95% CI 4.42-10.43) but was not significantly different when compared to MSAT (OR = 5.2, 95% CI 3.22-8.37; P-difference = 0.883) and RACD (OR = 4.08, 95% CI 2.55-6.53; P-difference = 0.29). Across both datasets, clustering became more prominent when transmission was low. However, limitations to our analysis include not accounting for any malaria control interventions in place, malaria seasonality, or the likely heterogeneity of transmission within study sites. Clustering may thus have been underestimated. CONCLUSIONS In areas where malaria transmission is peri-domestic, there are programmatic options for identifying households where residual infections are likely to be found. Combining these detection strategies with presumptively treating residents of index households over a sustained time period could contribute to malaria elimination efforts.
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Affiliation(s)
- Gillian Stresman
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, United Kingdom
- * E-mail:
| | - Charlie Whittaker
- Department of Infectious Disease Epidemiology, London Centre for Neglected Tropical Disease Research and MRC Centre for Outbreak Analysis and Modelling, Imperial College London, London, United Kingdom
| | - Hannah C. Slater
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
- PATH, Seattle, Washington, United States of America
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jackie Cook
- MRC Tropical Epidemiology Group, London School of Hygiene & Tropical Medicine, London, United Kingdom
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30
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Mlacha YP, Wang D, Chaki PP, Gavana T, Zhou Z, Michael MG, Khatib R, Chila G, Msuya HM, Chaki E, Makungu C, Lin K, Tambo E, Rumisha SF, Mkude S, Mahende MK, Chacky F, Vounatsou P, Tanner M, Masanja H, Aregawi M, Hertzmark E, Xiao N, Abdulla S, Zhou XN. Effectiveness of the innovative 1,7-malaria reactive community-based testing and response (1, 7-mRCTR) approach on malaria burden reduction in Southeastern Tanzania. Malar J 2020; 19:292. [PMID: 32799857 PMCID: PMC7429894 DOI: 10.1186/s12936-020-03363-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Accepted: 08/05/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND In 2015, a China-UK-Tanzania tripartite pilot project was implemented in southeastern Tanzania to explore a new model for reducing malaria burden and possibly scaling-out the approach into other malaria-endemic countries. The 1,7-malaria Reactive Community-based Testing and Response (1,7-mRCTR) which is a locally-tailored approach for reporting febrile malaria cases in endemic villages was developed to stop transmission and Plasmodium life-cycle. The (1,7-mRCTR) utilizes existing health facility data and locally trained community health workers to conduct community-level testing and treatment. METHODS The pilot project was implemented from September 2015 to June 2018 in Rufiji District, southern Tanzania. The study took place in four wards, two with low incidence and two with a higher incidence. One ward of each type was selected for each of the control and intervention arms. The control wards implemented the existing Ministry of Health programmes. The 1,7-mRCTR activities implemented in the intervention arm included community testing and treatment of malaria infection. Malaria case-to-suspect ratios at health facilities (HF) were aggregated by villages, weekly to identify the village with the highest ratio. Community-based mobile test stations (cMTS) were used for conducting mass testing and treatment. Baseline (pre) and endline (post) household surveys were done in the control and intervention wards to assess the change in malaria prevalence measured by the interaction term of 'time' (post vs pre) and arm in a logistic model. A secondary analysis also studied the malaria incidence reported at the HFs during the intervention. RESULTS Overall the 85 rounds of 1,7-mRCTR conducted in the intervention wards significantly reduced the odds of malaria infection by 66% (adjusted OR 0.34, 95% CI 0.26,0.44, p < 0001) beyond the effect of the standard programmes. Malaria prevalence in the intervention wards declined by 81% (from 26% (95% CI 23.7, 7.8), at baseline to 4.9% (95% CI 4.0, 5.9) at endline). In villages receiving the 1,7-mRCTR, the short-term case ratio decreased by over 15.7% (95% CI - 33, 6) compared to baseline. CONCLUSION The 1,7-mRCTR approach significantly reduced the malaria burden in the areas of high transmission in rural southern Tanzania. This locally tailored approach could accelerate malaria control and elimination efforts. The results provide the impetus for further evaluation of the effectiveness and scaling up of this approach in other high malaria burden countries in Africa, including Tanzania.
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Affiliation(s)
- Yeromin P Mlacha
- Ifakara Health Institute, P. O. Box 78378, Kiko Avenue, Mikocheni, Dar es Salaam, Tanzania.,Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Duoquan Wang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China
| | - Prosper P Chaki
- Ifakara Health Institute, P. O. Box 78378, Kiko Avenue, Mikocheni, Dar es Salaam, Tanzania.
| | - Tegemeo Gavana
- Ifakara Health Institute, P. O. Box 78378, Kiko Avenue, Mikocheni, Dar es Salaam, Tanzania
| | - Zhengbin Zhou
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China
| | - Mihayo G Michael
- Ifakara Health Institute, P. O. Box 78378, Kiko Avenue, Mikocheni, Dar es Salaam, Tanzania
| | - Rashid Khatib
- Ifakara Health Institute, P. O. Box 78378, Kiko Avenue, Mikocheni, Dar es Salaam, Tanzania
| | - Godlove Chila
- Ifakara Health Institute, P. O. Box 78378, Kiko Avenue, Mikocheni, Dar es Salaam, Tanzania
| | - Hajirani M Msuya
- Ifakara Health Institute, P. O. Box 78378, Kiko Avenue, Mikocheni, Dar es Salaam, Tanzania
| | - Exavery Chaki
- Ifakara Health Institute, P. O. Box 78378, Kiko Avenue, Mikocheni, Dar es Salaam, Tanzania
| | - Christina Makungu
- Ifakara Health Institute, P. O. Box 78378, Kiko Avenue, Mikocheni, Dar es Salaam, Tanzania
| | - Kangming Lin
- Guangxi Center for Disease Control and Prevention, Nanning, China
| | - Ernest Tambo
- Higher Institute of Health Sciences, Université des Montagnes, Bangangté, BP 208, Cameroon
| | - Susan F Rumisha
- National Institute for Medical Research (NIMR), P.O. Box 9653, Dar es Salaam, Tanzania
| | - Sigsbert Mkude
- Ifakara Health Institute, P. O. Box 78378, Kiko Avenue, Mikocheni, Dar es Salaam, Tanzania
| | - Muhidin K Mahende
- Ifakara Health Institute, P. O. Box 78378, Kiko Avenue, Mikocheni, Dar es Salaam, Tanzania
| | - Frank Chacky
- National Malaria Control, Ministry of Health, Community Development, Gender, Elderly and Children, Dodoma, Tanzania
| | - Penelope Vounatsou
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Marcel Tanner
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Honorati Masanja
- Ifakara Health Institute, P. O. Box 78378, Kiko Avenue, Mikocheni, Dar es Salaam, Tanzania
| | - Maru Aregawi
- The Global Malaria Programme (GMP), World Health Organization, Geneva, Switzerland
| | - Ellen Hertzmark
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Ning Xiao
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China
| | - Salim Abdulla
- Ifakara Health Institute, P. O. Box 78378, Kiko Avenue, Mikocheni, Dar es Salaam, Tanzania
| | - Xiao-Nong Zhou
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China
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Finding hotspots: development of an adaptive spatial sampling approach. Sci Rep 2020; 10:10939. [PMID: 32616757 PMCID: PMC7331748 DOI: 10.1038/s41598-020-67666-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 06/08/2020] [Indexed: 01/09/2023] Open
Abstract
The identification of disease hotspots is an increasingly important public health problem. While geospatial modeling offers an opportunity to predict the locations of hotspots using suitable environmental and climatological data, little attention has been paid to optimizing the design of surveys used to inform such models. Here we introduce an adaptive sampling scheme optimized to identify hotspot locations where prevalence exceeds a relevant threshold. Our approach incorporates ideas from Bayesian optimization theory to adaptively select sample batches. We present an experimental simulation study based on survey data of schistosomiasis and lymphatic filariasis across four countries. Results across all scenarios explored show that adaptive sampling produces superior results and suggest that similar performance to random sampling can be achieved with a fraction of the sample size.
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32
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Stuck L, Fakih BS, Al-Mafazy AWH, Hofmann NE, Holzschuh A, Grossenbacher B, Bennett A, Cotter C, Reaves E, Ali A, der Horst TV, Felger I, Hetzel MW, Yukich J. Malaria infection prevalence and sensitivity of reactive case detection in Zanzibar. Int J Infect Dis 2020; 97:337-346. [PMID: 32534138 PMCID: PMC8450816 DOI: 10.1016/j.ijid.2020.06.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/04/2020] [Accepted: 06/05/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Reactive case detection (RCD) is a commonly used strategy for malaria surveillance and response in elimination settings. Many approaches to RCD assume detectable infections are clustered within and around homes of passively detected cases (index households), which has been evaluated in a number of settings with disparate results. METHODS Household questionnaires and diagnostic testing were conducted following RCD investigations in Zanzibar, Tanzania, including the index household and up to 9 additional neighboring households. RESULTS Of 12,487 participants tested by malaria rapid diagnostic test (RDT), 3·2% of those residing in index households and 0·4% of those residing in non-index households tested positive (OR = 8·4; 95%CI: 5·7, 12·5). Of 6,281 participants tested by quantitative polymerase chain reaction (qPCR), 8·4% of those residing in index households and 1·3% of those residing in non-index households tested positive (OR = 7·1; 95%CI: 6·1, 10·9). Within households of index cases defined as imported, odds of qPCR-positivity amongst members reporting recent travel were 1·4 times higher than among those without travel history (95%CI: 0·2, 4·4). Amongst non-index households, odds of qPCR-detectable infection were no different between households located within 50 m of the index household as compared with those located farther away (OR = 0·8, 95%CI: 0·5, 1·4). Sensitivity of RDT to detect qPCR-detectable infections was 34% (95%CI: 26·4, 42·3). CONCLUSIONS Malaria prevalence in index households in Zanzibar is much higher than in non-index households, in which prevalence is very low. Travelers represent a high-risk population. Low sensitivity of RDTs due to a high prevalence of low-density infections results in an RCD system missing a large proportion of the parasite reservoir.
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Affiliation(s)
- Logan Stuck
- Tulane School of Public Health and Tropical Medicine, New Orleans, LA, USA.
| | - Bakar S Fakih
- Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
| | - Abdul-Wahid H Al-Mafazy
- Zanzibar Malaria Elimination Programme, Ministry of Health, Zanzibar, United Republic of Tanzania
| | - Natalie E Hofmann
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | - Aurel Holzschuh
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | - Benjamin Grossenbacher
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | - Adam Bennett
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, CA, USA
| | - Chris Cotter
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, CA, USA
| | - Erik Reaves
- U.S. President's Malaria Initiative, Malaria Branch, U.S. Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Abdullah Ali
- Zanzibar Malaria Elimination Programme, Ministry of Health, Zanzibar, United Republic of Tanzania
| | - Tina van der Horst
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | - Ingrid Felger
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | - Manuel W Hetzel
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | - Joshua Yukich
- Tulane School of Public Health and Tropical Medicine, New Orleans, LA, USA
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33
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Bhondoekhan FRP, Searle KM, Hamapumbu H, Lubinda M, Matoba J, Musonda M, Katowa B, Shields TM, Kobayashi T, Norris DE, Curriero FC, Stevenson JC, Thuma PE, Moss WJ. Improving the efficiency of reactive case detection for malaria elimination in southern Zambia: a cross-sectional study. Malar J 2020; 19:175. [PMID: 32381005 PMCID: PMC7206707 DOI: 10.1186/s12936-020-03245-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 04/23/2020] [Indexed: 01/20/2023] Open
Abstract
Background Reactive case detection (RCD) seeks to enhance malaria surveillance and control by identifying and treating parasitaemic individuals residing near index cases. In Zambia, this strategy starts with passive detection of symptomatic incident malaria cases at local health facilities or by community health workers, with subsequent home visits to screen-and-treat residents in the index case and neighbouring (secondary) households within a 140-m radius using rapid diagnostic tests (RDTs). However, a small circular radius may not be the most efficient strategy to identify parasitaemic individuals in low-endemic areas with hotspots of malaria transmission. To evaluate if RCD efficiency could be improved by increasing the probability of identifying parasitaemic residents, environmental risk factors and a larger screening radius (250 m) were assessed in a region of low malaria endemicity. Methods Between January 12, 2015 and July 26, 2017, 4170 individuals residing in 158 index and 531 secondary households were enrolled and completed a baseline questionnaire in the catchment area of Macha Hospital in Choma District, Southern Province, Zambia. Plasmodium falciparum prevalence was measured using PfHRP2 RDTs and quantitative PCR (qPCR). A Quickbird™ high-resolution satellite image of the catchment area was used to create environmental risk factors in ArcGIS, and generalized estimating equations were used to evaluate associations between risk factors and secondary households with parasitaemic individuals. Results The parasite prevalence in secondary (non-index case) households was 0.7% by RDT and 1.8% by qPCR. Overall, 8.5% (n = 45) of secondary households had at least one resident with parasitaemia by qPCR or RDT. The risk of a secondary household having a parasitaemic resident was significantly increased in proximity to higher order streams and marginally with increasing distance from index households. The adjusted OR for proximity to third- and fifth-order streams were 2.97 (95% CI 1.04–8.42) and 2.30 (95% CI 1.04–5.09), respectively, and that for distance to index households for each 50 m was 1.24 (95% CI 0.98–1.58). Conclusion Applying proximity to streams as a screening tool, 16% (n = 3) more malaria-positive secondary households were identified compared to using a 140-m circular screening radius. This analysis highlights the potential use of environmental risk factors as a screening strategy to increase RCD efficiency.
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Affiliation(s)
- Fiona R P Bhondoekhan
- MACS/WIHS Combined Cohort Study, Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.
| | - Kelly M Searle
- MACS/WIHS Combined Cohort Study, Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.,Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, USA
| | | | | | | | | | - Ben Katowa
- Macha Research Trust, Choma District, Zambia
| | - Timothy M Shields
- MACS/WIHS Combined Cohort Study, Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Tamaki Kobayashi
- MACS/WIHS Combined Cohort Study, Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Douglas E Norris
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Frank C Curriero
- MACS/WIHS Combined Cohort Study, Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Jennifer C Stevenson
- Macha Research Trust, Choma District, Zambia.,Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Philip E Thuma
- Macha Research Trust, Choma District, Zambia.,Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - William J Moss
- MACS/WIHS Combined Cohort Study, Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.,Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
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34
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Taylor SM, Sumner KM, Freedman B, Mangeni JN, Obala AA, Prudhomme O'Meara W. Direct Estimation of Sensitivity of Plasmodium falciparum Rapid Diagnostic Test for Active Case Detection in a High-Transmission Community Setting. Am J Trop Med Hyg 2020; 101:1416-1423. [PMID: 31674301 DOI: 10.4269/ajtmh.19-0558] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Community-based active case detection of malaria parasites with conventional rapid diagnostic tests (cRDTs) is a strategy used most commonly in low-transmission settings. We estimated the sensitivity of this approach in a high-transmission setting in Western Kenya. We tested 3,547 members of 912 households identified in 2013-2014 by index children with (case) and without (control) cRDT-positive malaria. All were tested for Plasmodium falciparum with both a cRDT targeting histidine-rich protein 2 and with an ultrasensitive real-time polymerase chain reaction (PCR). We computed cRDT sensitivity against PCR as the referent, compared prevalence between participant types, and estimated cRDT detectability as a function of PCR-estimated parasite density. Parasite prevalence was 22.9% by cRDTs and 61.5% by PCR. Compared with children aged < 5 years or adults aged > 15 years, geometric mean parasite densities (95% CI) were highest in school-age children aged 5-15 years (8.4 p/uL; 6.6-10.6). The overall sensitivity of cRDT was 36%; among asymptomatic household members, cRDT sensitivity was 25.5% and lowest in adults aged > 15 years (15.8%). When modeled as a function of parasite density, relative to school-age children, the probability of cRDT positivity was reduced in both children aged < 5 years (odds ratio [OR] 0.48; 95% CI: 0.34-0.69) and in adults aged > 15 years (OR: 0.35; 95% CI: 0.27-0.47). An HRP2-detecting cRDT had poor sensitivity for active P. falciparum case detection in asymptomatic community members, and sensitivity was lowest in highly prevalent low-density infections and in adults. Future studies can model the incremental effects of high-sensitivity rapid diagnostic tests and the impacts on transmission.
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Affiliation(s)
- Steve M Taylor
- Division of Infectious Diseases, Duke University Medical Center, Durham, North Carolina.,Department of Epidemiology, University of North Carolina Gillings School of Global Public Health, Chapel Hill, North Carolina.,Duke Global Health Institute, Durham, North Carolina
| | - Kelsey M Sumner
- Department of Epidemiology, University of North Carolina Gillings School of Global Public Health, Chapel Hill, North Carolina.,Division of Infectious Diseases, Duke University Medical Center, Durham, North Carolina
| | - Betsy Freedman
- Division of Infectious Diseases, Duke University Medical Center, Durham, North Carolina
| | | | - Andrew A Obala
- College of Health Sciences, Moi University, Eldoret, Kenya
| | - Wendy Prudhomme O'Meara
- College of Health Sciences, Moi University, Eldoret, Kenya.,Duke Global Health Institute, Durham, North Carolina.,Division of Infectious Diseases, Duke University Medical Center, Durham, North Carolina
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35
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Pringle JC, Tessema S, Wesolowski A, Chen A, Murphy M, Carpi G, Shields TM, Hamapumbu H, Searle KM, Kobayashi T, Katowa B, Musonda M, Stevenson JC, Thuma PE, Greenhouse B, Moss WJ, Norris DE. Genetic Evidence of Focal Plasmodium falciparum Transmission in a Pre-elimination Setting in Southern Province, Zambia. J Infect Dis 2020; 219:1254-1263. [PMID: 30445612 DOI: 10.1093/infdis/jiy640] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 11/09/2018] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Southern Province, Zambia has experienced a dramatic decline in Plasmodium falciparum malaria transmission in the past decade and is targeted for elimination. Zambia's National Malaria Elimination Program recommends reactive case detection (RCD) within 140 m of index households to enhance surveillance and eliminate remaining transmission foci. METHODS To evaluate whether RCD captures local transmission, we genotyped 26 microsatellites from 106 samples collected from index (n = 27) and secondary (n = 79) cases detected through RCD in the Macha Hospital catchment area between January 2015 and April 2016. RESULTS Participants from the same RCD event harbored more genetically related parasites than those from different RCD events, suggesting that RCD captures, at least in part, infections related through local transmission. Related parasites clustered in space and time, up to at least 250 m from index households. Spatial analysis identified a putative focal transmission hotspot. CONCLUSIONS The current RCD strategy detects focal transmission events, although programmatic guidelines to screen within 140 m of index households may fail to capture all secondary cases. This study highlights the utility of parasite genetic data in assessing programmatic interventions, and similar approaches may be useful to malaria elimination programs seeking to tailor intervention strategies to the underlying transmission epidemiology.
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Affiliation(s)
- Julia C Pringle
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | - Amy Wesolowski
- Department of Epidemiology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Anna Chen
- Department of Medicine, University of California, San Francisco
| | - Maxwell Murphy
- Department of Medicine, University of California, San Francisco.,Division of Biostatistics, University of California, Berkeley
| | - Giovanna Carpi
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.,Department of Biological Sciences, Purdue University, West Lafayette, Indiana
| | - Timothy M Shields
- Department of Epidemiology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | - Kelly M Searle
- Department of Epidemiology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Tamaki Kobayashi
- Department of Epidemiology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | | | - Jennifer C Stevenson
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.,Macha Research Trust, Choma, Zambia
| | | | - Bryan Greenhouse
- Department of Medicine, University of California, San Francisco.,Chan Zuckerberg Biohub, San Francisco, California
| | - William J Moss
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.,Department of Epidemiology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Douglas E Norris
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
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36
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Khandekar E, Kramer R, Ali AS, Al-Mafazy AW, Egger JR, LeGrand S, Mkali HR, McKay M, Ngondi JM. Evaluating Response Time in Zanzibar's Malaria Elimination Case-Based Surveillance-Response System. Am J Trop Med Hyg 2019; 100:256-263. [PMID: 30526729 DOI: 10.4269/ajtmh.17-0546] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
As countries transition toward malaria elimination, malaria programs rely on surveillance-response systems, which are often supported by web- and mobile phone-based reporting tools. Such surveillance-response systems are interventions for elimination, making it important to determine if they are operating optimally. A metric to measure this by is timeliness. This study used a mixed-methods approach to investigate the response time of Zanzibar's malaria elimination surveillance-response system, Malaria Case Notification (MCN). MCN conducts both passive and reactive case detection, supported by a mobile phone-based reporting tool called Coconut Surveillance. Using data obtained from RTI International and the Zanzibar Malaria Elimination Program (ZAMEP), analysis of summary statistics was conducted to investigate the association of response time with geography, and time series techniques were used to investigate trends in response time and its association with the number of reported cases. Results indicated that response time varied by the district in Zanzibar (0.6-6.05 days) and that it was not associated with calendar time or the number of reported cases. Survey responses and focus groups with a cadre of health workers, district malaria surveillance officers, shed light on operational challenges faced during case investigation, such as incomplete health records and transportation issues, which stem from deficiencies in aspects of ZAMEP's program management. These findings illustrate that timely response for malaria elimination depends on effective program management, despite the automation of web-based or mobile phone-based tools. For surveillance-response systems to work optimally, malaria programs should ensure that optimal management practices are in place.
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Affiliation(s)
- Eeshan Khandekar
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Randall Kramer
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Abdullah S Ali
- Zanzibar Malaria Elimination Programme, Zanzibar, Tanzania
| | | | - Joseph R Egger
- Duke Global Health Institute, Duke University, Durham, North Carolina
| | - Sara LeGrand
- Duke Global Health Institute, Duke University, Durham, North Carolina
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37
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Stresman G, Bousema T, Cook J. Malaria Hotspots: Is There Epidemiological Evidence for Fine-Scale Spatial Targeting of Interventions? Trends Parasitol 2019; 35:822-834. [PMID: 31474558 DOI: 10.1016/j.pt.2019.07.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 07/29/2019] [Accepted: 07/29/2019] [Indexed: 12/20/2022]
Abstract
As data at progressively granular spatial scales become available, the temptation is to target interventions to areas with higher malaria transmission - so-called hotspots - with the aim of reducing transmission in the wider community. This paper reviews literature to determine if hotspots are an intrinsic feature of malaria epidemiology and whether current evidence supports hotspot-targeted interventions. Hotspots are a consistent feature of malaria transmission at all endemicities. The smallest spatial unit capable of supporting transmission is the household, where peri-domestic transmission occurs. Whilst the value of focusing interventions to high-burden areas is evident, there is currently limited evidence that local-scale hotspots fuel transmission. As boundaries are often uncertain, there is no conclusive evidence that hotspot-targeted interventions accelerate malaria elimination.
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Affiliation(s)
- Gillian Stresman
- Infection Biology Department, London School of Hygiene and Tropical Medicine, London, UK.
| | - Teun Bousema
- Radboud University Medical Centre, Department of Microbiology, HB Nijmegen, The Netherlands.
| | - Jackie Cook
- Medical Research Council (MRC) Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
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38
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Baltzell KA, Maglior A, Bangu K, Mngadi N, Prach LM, Whittemore B, Ntshalintshali N, Saini M, Dlamini N, Kunene S, Hsiang MS. "We were afraid of the lion that has roared next to us"; community response to reactive focal mass drug administration for malaria in Eswatini (formerly Swaziland). Malar J 2019; 18:238. [PMID: 31307494 PMCID: PMC6631448 DOI: 10.1186/s12936-019-2877-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 07/09/2019] [Indexed: 11/25/2022] Open
Abstract
Background Reactive focal mass drug administration (rfMDA), or presumptive treatment without malaria testing of household members and neighbours of a passively identified malaria case, is currently being explored as a possible malaria elimination strategy in low transmission settings. One of the primary factors determining the effectiveness of rfMDA on reducing or interrupting transmission is achieving high coverage of the target population with drug administration. This study aims to explore the acceptability of rfMDA and identify facilitators and barriers to its potential implementation, as well as the community’s general knowledge, attitudes and beliefs with regard to malaria elimination. Methods A qualitative study was performed using focus group discussions (FGDs) among villagers that received rfMDA through the National Malaria Control Programme in the low transmission setting of Eswatini as part of a 2-year clinical trial. FGDs were audio-recorded, transcribed and translated into English. All transcripts were managed in Dedoose and underwent qualitative content analysis. Results The majority of participants perceived their community to be at high risk of malaria. Witnessing others in their community suffer from malaria, proximity to Mozambique, various ecological factors, and the presence of mosquitoes contributed to this perception. The greatest motivator of participation in rfMDA was witnessing someone else suffer from malaria, since most participants had not personally experienced malaria themselves. Participants valued the education on rfMDA and on malaria in general, particularly when communicated by nurses and other health workers from the Ministry of Health. Participants were overwhelmingly motivated to participate in rfMDA in order to obtain protection from malaria. Most participants did not understand the concept of sub-clinical infection and, therefore, did not perceive the anti-malarial medication given in rfMDA to be a treatment medication. Conclusions Perceived risk for malaria was a major driver of acceptability; therefore, future intervention campaigns could aim to better quantify risk to inform interventions and encourage uptake. There were misunderstandings about the asymptomatic reservoir of parasites in humans. Given that this phenomenon is the rationale for rfMDA, this misunderstanding could threaten the uptake of the intervention if it persists in the community. Using local authorities to deliver messaging, additional education on this concept with re-inforcement that risk of malaria is ongoing, even in the absence of frequent cases, may help to maximize and maintain acceptability.
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Affiliation(s)
- Kimberly A Baltzell
- Dept of Family Health Care Nursing, UCSF, San Francisco, CA, USA. .,Institute for Global Health Sciences, UCSF, San Francisco, CA, USA.
| | - Alysse Maglior
- Institute for Global Health Sciences, UCSF, San Francisco, CA, USA
| | - Khaya Bangu
- National Malaria Programme, Eswatini Ministry of Health, Manzini, Swaziland
| | - Nontokozo Mngadi
- Clinton Health Access Initiative, Eswatini Office, Mbabane, Swaziland
| | - Lisa M Prach
- Malaria Elimination Initiative, Global Health Group, UCSF, San Francisco, CA, USA
| | - Brooke Whittemore
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | | | - Manik Saini
- Clinton Health Access Initiative, Eswatini Office, Mbabane, Swaziland
| | - Nomcebo Dlamini
- National Malaria Programme, Eswatini Ministry of Health, Manzini, Swaziland
| | - Simon Kunene
- National Malaria Programme, Eswatini Ministry of Health, Manzini, Swaziland
| | - Michelle S Hsiang
- Malaria Elimination Initiative, Global Health Group, UCSF, San Francisco, CA, USA.,Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Department of Pediatrics, UCSF, San Francisco, CA, USA
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Smith JL, Ghimire P, Rijal KR, Maglior A, Hollis S, Andrade-Pacheco R, Das Thakur G, Adhikari N, Thapa Shrestha U, Banjara MR, Lal BK, Jacobson JO, Bennett A. Designing malaria surveillance strategies for mobile and migrant populations in Nepal: a mixed-methods study. Malar J 2019; 18:158. [PMID: 31053075 PMCID: PMC6500027 DOI: 10.1186/s12936-019-2791-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 04/23/2019] [Indexed: 11/10/2022] Open
Abstract
Background As malaria cases have declined throughout Nepal, imported cases comprise an increasing share of the remaining malaria caseload, yet how to effectively target mobile and migrant populations (MMPs) at greatest risk is not well understood. This formative research aimed to confirm the link between imported and indigenous cases, characterize high-risk MMPs, and identify opportunities to adapt surveillance and intervention strategies to them. Methods The study used a mixed-methods approach in three districts in far and mid-western Nepal, including (i) a retrospective analysis of passive surveillance data, (ii) a quantitative health facility-based survey of imported cases and their MMP social contacts recruited by peer-referral, and (iii) focus group (FG) discussions and key informant interviews (KIIs) with a subset of survey participants. Retrospective case data were summarised and the association between monthly indigenous case counts and importation rates in the previous month was investigated using Bayesian spatio-temporal regression models. Quantitative data from structured interviews were summarised to develop profiles of imported cases and MMP contacts, including travel characteristics and malaria knowledge, attitudes and practice. Descriptive statistics of the size of cases’ MMP social networks are presented as a measure of potential programme reach. To explore opportunities and barriers for targeted malaria surveillance, data from FGs and KIIs were formally analysed using a thematic content analysis approach. Results More than half (54.1%) of malaria cases between 2013 and 2016 were classified as imported and there was a positive association between monthly indigenous cases (incidence rate ratio (IRR) 1.02 95% CI 1.01–1.03) and the previous month’s case importation rate. High-risk MMPs were identified as predominantly adult male labourers, who travel to malaria endemic areas of India, often lack a basic understanding of malaria transmission and prevention, rarely use ITNs while travelling and tend not to seek treatment when ill or prefer informal private providers. Important obstacles were identified to accessing Nepali MMPs at border crossings and at workplaces within India. However, strong social connectivity during travel and while in India, as well as return to Nepal for large seasonal festivals, provide opportunities for peer-referral-based and venue-based surveillance and intervention approaches, respectively. Conclusions Population mobility and imported malaria cases from India may help to drive local transmission in border areas of far and mid-western Nepal. Enhanced surveillance targeting high-risk MMP subgroups would improve early malaria diagnosis and treatment, as well as provide a platform for education and intervention campaigns. A combination of community-based approaches is likely necessary to achieve malaria elimination in Nepal. Electronic supplementary material The online version of this article (10.1186/s12936-019-2791-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jennifer L Smith
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, USA
| | - Prakash Ghimire
- Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu, Nepal.
| | - Komal Raj Rijal
- Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu, Nepal
| | - Alysse Maglior
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, USA
| | - Sara Hollis
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, USA
| | - Ricardo Andrade-Pacheco
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, USA
| | - Garib Das Thakur
- Epidemiology and Diseases Control Division, Ministry of Health and Population, Teku, Kathmandu, Nepal
| | - Nabaraj Adhikari
- Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu, Nepal
| | | | - Megha Raj Banjara
- Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu, Nepal
| | - Bibek Kumar Lal
- Epidemiology and Diseases Control Division, Ministry of Health and Population, Teku, Kathmandu, Nepal
| | - Jerry O Jacobson
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, USA
| | - Adam Bennett
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, USA
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40
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Haiyambo DH, Uusiku P, Mumbengegwi D, Pernica JM, Bock R, Malleret B, Rénia L, Greco B, Quaye IK. Molecular detection of P. vivax and P. ovale foci of infection in asymptomatic and symptomatic children in Northern Namibia. PLoS Negl Trop Dis 2019; 13:e0007290. [PMID: 31042707 PMCID: PMC6513099 DOI: 10.1371/journal.pntd.0007290] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 05/13/2019] [Accepted: 03/11/2019] [Indexed: 11/19/2022] Open
Abstract
Background Knowledge of the foci of Plasmodium species infections is critical for a country with an elimination agenda. Namibia is targeting malaria elimination by 2020. To support decision making regarding targeted intervention, we examined for the first time, the foci of Plasmodium species infections and regional prevalence in northern Namibia, using nested and quantitative polymerase chain reaction (PCR) methods. Methods We used cross-sectional multi-staged sampling to select 952 children below 9 years old from schools and clinics in seven districts in northern Namibia, to assess the presence of Plasmodium species. Results The median participant age was 6 years (25–75%ile 4–8 y). Participants had a median hemoglobin of 12.0 g/dL (25–75%ile 11.1–12.7 g/dL), although 21% of the cohort was anemic, with anemia being severer in the younger population (p<0.002). Most of children with Plasmodium infection were asymptomatic (63.4%), presenting a challenge for elimination. The respective parasite prevalence for Plasmodium falciparum (Pf), Plasmodium vivax (Pv) and Plasmodium ovale curtisi (Po) were (4.41%, 0.84% and 0.31%); with Kavango East and West (10.4%, 6.19%) and Ohangwena (4.5%) having the most prevalence. Pv was localized in Ohangwena, Omusati and Oshana, while Po was found in Kavango. All children with Pv/Pf coinfections in Ohangwena, had previously visited Angola, affirming that perennial migrations are risks for importation of Plasmodium species. The mean hemoglobin was lower in those with Plasmodium infection compared to those without (0.96 g/dL less, 95%CI 0.40–1.52 g/dL less, p = 0.0009) indicating that quasi-endemicity exists in the low transmission setting. Conclusions We conclude that Pv and Po species are present in northern Namibia. Additionally, the higher number of asymptomatic infections present challenges to the efforts at elimination for the country. Careful planning, coordination with neighboring Angola and execution of targeted active intervention, will be required for a successful elimination agenda. Namibia is a member of the SADC elimination 8 (E8) group with a target to eliminate malaria by 2020. This target stems from years of aggressive interventional strategies that has led to significant reductions in morbidity and mortality. The focus of this strategy is mainly on Plasmodium falciparum as the primary parasite species. Foci of transmission is found in the northern border with Angola and Zambia, which also carries the highest population density. Recently as part of the elimination efforts to predict areas likely to have rebound epidemics, three regions Ohangwena, Kavango and Zambezi were identified. In order to affirm these findings and decision-making process for intervention, we assessed the parasite prevalence in 7 northern regional sites for four Plasmodium species. We identified Pv and Po curtisi parasites in Omusati, Ohangwena and Kavango, as well as a significant number of asymptomatic Pf and Pv infections, part of which may be due to importation from neighboring Angola. As Namibia is targeting elimination by 2020, careful thought and planning will be required to reach the goal.
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Affiliation(s)
- Daniel H. Haiyambo
- Department of Biochemistry and Microbiology, University of Namibia School of Medicine, Windhoek, Namibia
| | - Petrina Uusiku
- National Vector Borne Disease Control Program, Ministry of Health and Social Services, Windhoek, Namibia
| | - Davies Mumbengegwi
- Multidisciplinary Research Center, University of Namibia, Windhoek, Namibia
| | - Jeff M. Pernica
- Division of Infectious Disease, Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
| | - Ronnie Bock
- Department of Biology, University of Namibia, Windhoek, Namibia
| | - Benoit Malleret
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Biopolis, Singapore
| | - Laurent Rénia
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Biopolis, Singapore
| | - Beatrice Greco
- Research and Development Access, Global Health Institute, Merck KGaA, Darmstadt, Germany
| | - Isaac K. Quaye
- Department of Biochemistry and Microbiology, University of Namibia School of Medicine, Windhoek, Namibia
- * E-mail: ,
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Jaiteh F, Masunaga Y, Okebe J, D'Alessandro U, Balen J, Bradley J, Gryseels C, Ribera JM, Grietens KP. Community perspectives on treating asymptomatic infections for malaria elimination in The Gambia. Malar J 2019; 18:39. [PMID: 30777112 PMCID: PMC6378745 DOI: 10.1186/s12936-019-2672-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 02/10/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Innovative and cost-effective strategies that clear asymptomatic malaria infections are required to reach malaria elimination goals, but remain a challenge. This mixed methods study explored people's attitudes towards the reactive treatment of compound contacts of malaria cases with a 3-day course of dihydroartemisinin-piperaquine (DHAP), the socio-cultural representations of asymptomatic infections, and more specifically their treatment. METHODS Prior to the start of the intervention, a sequential mixed method study was carried out. Qualitative data collection involved in-depth interviews and participant observations (including informal conversations) with key informants from the trial communities and the trial staff. Quantitative data were derived from a pre-trial cross-sectional survey on health literacy and health-seeking behaviour among randomly selected members of the study communities. RESULTS In the pre-trial cross-sectional survey, 73% of respondents reported that malaria could be hidden in the body without symptoms. Whilst this may be interpreted as people's comprehension of asymptomatic malaria, qualitative data indicated that informants had different interpretations of asymptomatic disease than the biomedical model. It was described as: (i) a minor illness that does not prevent people carrying out daily activities; (ii) an illness that oscillates between symptomatic and asymptomatic phases; and, (iii) a condition where disease agents are present in the body but remain hidden, without signs and symptoms, until something triggers their manifestation. Furthermore, this form of hidden malaria was reported to be most present in those living in the same compound with a malaria case (71%). CONCLUSION Treating asymptomatic malaria with pharmaceuticals was considered acceptable. However, people felt uncertain to take treatment without screening for malaria first, largely due to the lack of symptoms. Knowledge of asymptomatic malaria was not a strong re-inforcement for treatment adherence. In this study, the pre-intervention active engagement of communities existed of having people co-design accurate information messages about their personal risk of malaria, which increased their trust in expert knowledge and thus proved essential for the successful implementation of the community-based intervention.
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Affiliation(s)
- Fatou Jaiteh
- Medical Anthropology Unit, Institute of Tropical Medicine, Antwerp, Belgium.
- Medical Research Council Unit the Gambia at the London, School of Hygiene and Tropical Medicine, Fajara, The Gambia.
- Faculty of Social and Behavioural Science, Department of Sociology and Anthropology, University of Amsterdam, Amsterdam, The Netherlands.
| | - Yoriko Masunaga
- Medical Anthropology Unit, Institute of Tropical Medicine, Antwerp, Belgium
- Faculty of Social and Behavioural Science, Department of Sociology and Anthropology, University of Amsterdam, Amsterdam, The Netherlands
| | - Joseph Okebe
- Medical Research Council Unit the Gambia at the London, School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Umberto D'Alessandro
- Medical Research Council Unit the Gambia at the London, School of Hygiene and Tropical Medicine, Fajara, The Gambia
- London School of Hygiene and Tropical Medicine, London, UK
| | - Julie Balen
- School of Health and Related Research (ScHARR), The University of Sheffield, Sheffield, UK
| | - John Bradley
- London School of Hygiene and Tropical Medicine, London, UK
| | - Charlotte Gryseels
- Medical Anthropology Unit, Institute of Tropical Medicine, Antwerp, Belgium
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McCreesh P, Mumbengegwi D, Roberts K, Tambo M, Smith J, Whittemore B, Kelly G, Moe C, Murphy M, Chisenga M, Greenhouse B, Ntuku H, Kleinschmidt I, Sturrock H, Uusiku P, Gosling R, Bennett A, Hsiang MS. Subpatent malaria in a low transmission African setting: a cross-sectional study using rapid diagnostic testing (RDT) and loop-mediated isothermal amplification (LAMP) from Zambezi region, Namibia. Malar J 2018; 17:480. [PMID: 30567537 PMCID: PMC6299963 DOI: 10.1186/s12936-018-2626-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 12/11/2018] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Subpatent malaria infections, or low-density infections below the detection threshold of microscopy or standard rapid diagnostic testing (RDT), can perpetuate persistent transmission and, therefore, may be a barrier for countries like Namibia that are pursuing malaria elimination. This potential burden in Namibia has not been well characterized. METHODS Using a two-stage cluster sampling, cross-sectional design, subjects of all age were enrolled during the end of the 2015 malaria transmission season in Zambezi region, located in northeast Namibia. Malaria RDTs were performed with subsequent gold standard testing by loop-mediated isothermal amplification (LAMP) using dried blood spots. Infection prevalence was measured and the diagnostic accuracy of RDT calculated. Relationships between recent fever, demographics, epidemiological factors, and infection were assessed. RESULTS Prevalence of Plasmodium falciparum malaria infection was low: 0.8% (16/1919) by RDT and 2.2% (43/1919) by LAMP. All but one LAMP-positive infection was RDT-negative. Using LAMP as gold standard, the sensitivity and specificity of RDT were 2.3% and 99.2%, respectively. Compared to LAMP-negative infections, a higher portion LAMP-positive infections were associated with fever (45.2% vs. 30.4%, p = 0.04), though 55% of infections were not associated with fever. Agricultural occupations and cattle herding were significantly associated with LAMP-detectable infection (Adjusted ORs 5.02, 95% CI 1.77-14.23, and 11.82, 95% CI 1.06-131.81, respectively), while gender, travel, bed net use, and indoor residual spray coverage were not. CONCLUSIONS This study presents results from the first large-scale malaria cross-sectional survey from Namibia using molecular testing to characterize subpatent infections. Findings suggest that fever history and standard RDTs are not useful to address this burden. Achievement of malaria elimination may require active case detection using more sensitive point-of-care diagnostics or presumptive treatment and targeted to high-risk groups.
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Affiliation(s)
- Patrick McCreesh
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA.,Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Davis Mumbengegwi
- Multidisciplinary Research Center, University of Namibia, Windhoek, Namibia
| | - Kathryn Roberts
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Munyaradzi Tambo
- Multidisciplinary Research Center, University of Namibia, Windhoek, Namibia
| | - Jennifer Smith
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Brooke Whittemore
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Gerard Kelly
- Burnet Institute for Medical Research and Public Health, Melbourne, Australia
| | - Caitlin Moe
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Max Murphy
- Division of HIV, Infectious Diseases and Global Medicine, Department of Medicine, UCSF, San Francisco, CA, USA
| | - Mukosha Chisenga
- Multidisciplinary Research Center, University of Namibia, Windhoek, Namibia
| | - Bryan Greenhouse
- Division of HIV, Infectious Diseases and Global Medicine, Department of Medicine, UCSF, San Francisco, CA, USA
| | - Henry Ntuku
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Immo Kleinschmidt
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK.,Wits Research Institute for Malaria, University of Witwatersrands, Johannesburg, South Africa
| | - Hugh Sturrock
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Petrina Uusiku
- National Vectorborne Disease Control Programme, Namibia Ministry of Health and Social Services, Windhoek, Namibia
| | - Roland Gosling
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Adam Bennett
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Michelle S Hsiang
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA. .,Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA. .,Department of Pediatrics, UCSF Benioff Children's Hospital, San Francisco, CA, USA.
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Naing C, Whittaker MA, Tanner M. Inter-sectoral approaches for the prevention and control of malaria among the mobile and migrant populations: a scoping review. Malar J 2018; 17:430. [PMID: 30445959 PMCID: PMC6240188 DOI: 10.1186/s12936-018-2562-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 11/01/2018] [Indexed: 02/05/2023] Open
Abstract
Background Malaria cases among mobile and migrant populations (MMPs) represent a large and important reservoir for transmission, if undetected or untreated. The objectives of this review were to identify which intersectoral actions have been taken and how they are applied to interventions targeted at the MMPs and also to assess the effect of interventions targeted to these special groups of population. Results A total of 36 studies met the inclusion criteria for this review. Numerous stakeholders were identified as involved in the intersectoral actions to defeat malaria amongst MMPs. Almost all studies discussed the involvement of Ministry of Health/Public Health (MOH/MOPH). The most frequently assessed intervention among the studies that were included was the coverage and utilization of insecticide-treated nets as personal protective measures (40.5%), followed by the intervention of early diagnoses and treatment of malaria (33.3%), the surveillance and response activities (13.9%) and the behaviour change communication (8.3%). There is a dearth of information on how these stakeholders shared roles and responsibilities for implementation, and about the channels of communication between-and-within the partners and with the MOH/MOPH. Despite limited details in the studies, the intermediate outcomes showed some evidence that the intersectoral collaborations contributed to improvement in knowledge about malaria, initiation and promotion of bed nets utilization, increased access to diagnosis and treatment in a surveillance context and contributed towards a reduction in malaria transmission. Overall, a high proportion of the targeted MMPs was equipped with correct knowledge about malaria transmission (70%, 95% CI 57–83%). Interventions targeting the use of bed nets utilization were two times more likely to reduce malaria incidence amongst the targeted MMPs (summary OR 2.01, 95% CI 1.43–2.6) than the non-users. The various intersectoral actions were often more vertically organized and not fully integrated in a systemic way within a given country or sub-national administrative setting. Conclusion Findings suggest that interventions supported by the multiple stakeholders had a significant impact on the reduction of malaria transmission amongst the targeted MMPs. Well-designed studies from different countries are recommended to robustly assess the role of intersectoral interventions targeted to MMPs and their impact on the reduction of transmission. Electronic supplementary material The online version of this article (10.1186/s12936-018-2562-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Cho Naing
- Institute for Research, Development and Innovation (IRDI), International Medical University, Kuala Lumpur, Malaysia. .,Division of Tropical Health and Medicine, James Cook University, Townsville, QLD, Australia.
| | - Maxine A Whittaker
- Division of Tropical Health and Medicine, James Cook University, Townsville, QLD, Australia
| | - Marcel Tanner
- Swiss Tropical and Public Health Institute, Basel, Switzerland
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Zemene E, Koepfli C, Tiruneh A, Yeshiwondim AK, Seyoum D, Lee MC, Yan G, Yewhalaw D. Detection of foci of residual malaria transmission through reactive case detection in Ethiopia. Malar J 2018; 17:390. [PMID: 30367636 PMCID: PMC6203988 DOI: 10.1186/s12936-018-2537-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 10/20/2018] [Indexed: 12/18/2022] Open
Abstract
Background Sub-microscopic and asymptomatic infections could be bottlenecks to malaria elimination efforts in Ethiopia. This study determined the prevalence of malaria, and individual and household-level factors associated with Plasmodium infections obtained following detection of index cases in health facilities in Jimma Zone. Methods Index malaria cases were passively detected and tracked in health facilities from June to November 2016. Moreover, family members of the index houses and neighbours located within approximately 200 m from the index houses were also screened for malaria. Results A total of 39 index cases initiated the reactive case detection of 726 individuals in 116 households. Overall, the prevalence of malaria using microscopy and PCR was 4.0% and 8.96%, respectively. Seventeen (43.6%) of the index cases were from Doyo Yaya kebele, where parasite prevalence was higher. The majority of the malaria cases (90.74%) were asymptomatic. Fever (AOR = 12.68, 95% CI 3.34–48.18) and history of malaria in the preceding 1 year (AOR = 3.62, 95% CI 1.77–7.38) were significant individual-level factors associated with detection of Plasmodium infection. Moreover, living in index house (AOR = 2.22, 95% CI 1.16–4.27), house with eave (AOR = 2.28, 95% CI 1.14–4.55), area of residence (AOR = 6.81, 95% CI 2.49–18.63) and family size (AOR = 3.35, 95% CI 1.53–7.33) were main household-level predictors for residual malaria transmission. Conclusion The number of index cases per kebele may enhance RACD efforts to detect additional malaria cases in low transmission settings. Asymptomatic and sub-microscopic infections were high in the study area, which need new or improved surveillance tools for malaria elimination efforts.
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Affiliation(s)
- Endalew Zemene
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia.
| | - Cristian Koepfli
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
| | - Abebaw Tiruneh
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
| | | | - Dinberu Seyoum
- Department of Statistics, College of Natural Sciences, Jimma University, Jimma, Ethiopia
| | - Ming-Chieh Lee
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
| | - Delenasaw Yewhalaw
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia.,Tropical and Infectious Diseases Research Centre, Jimma University, Jimma, Ethiopia
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Stresman GH, Mwesigwa J, Achan J, Giorgi E, Worwui A, Jawara M, Di Tanna GL, Bousema T, Van Geertruyden JP, Drakeley C, D'Alessandro U. Do hotspots fuel malaria transmission: a village-scale spatio-temporal analysis of a 2-year cohort study in The Gambia. BMC Med 2018; 16:160. [PMID: 30213275 PMCID: PMC6137946 DOI: 10.1186/s12916-018-1141-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 07/31/2018] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Despite the biological plausibility of hotspots fueling malaria transmission, the evidence to support this concept has been mixed. If transmission spreads from high burden to low burden households in a consistent manner, then this could have important implications for control and elimination program development. METHODS Data from a longitudinal cohort in The Gambia was analyzed. All consenting individuals residing in 12 villages across the country were sampled monthly from June (dry season) to December 2013 (wet season), in April 2014 (mid dry season), and monthly from June to December 2014. A study nurse stationed within each village recorded passively detected malaria episodes between visits. Plasmodium falciparum infections were determined by polymerase chain reaction and analyzed using a geostatistical model. RESULTS Household-level observed monthly incidence ranged from 0 to 0.50 infection per person (interquartile range = 0.02-0.10) across the sampling months, and high burden households exist across all study villages. There was limited evidence of a spatio-temporal pattern at the monthly timescale irrespective of transmission intensity. Within-household transmission was the most plausible hypothesis examined to explain the observed heterogeneity in infections. CONCLUSIONS Within-village malaria transmission patterns are concentrated in a small proportion of high burden households, but patterns are stochastic regardless of endemicity. Our findings support the notion of transmission occurring at the household and village scales but not the use of a targeted approach to interrupt spreading of infections from high to low burden areas within villages in this setting.
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Affiliation(s)
- Gillian H Stresman
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK.
| | - Julia Mwesigwa
- Medical Research Council Unit The Gambia at London School of Hygiene & Tropical Medicine, Fajara, The Gambia.,University of Antwerp, Antwerp, Belgium
| | - Jane Achan
- Medical Research Council Unit The Gambia at London School of Hygiene & Tropical Medicine, Fajara, The Gambia.,University of Antwerp, Antwerp, Belgium
| | - Emanuele Giorgi
- CHICAS, Lancaster Medical School, Lancaster University, Lancaster, UK
| | - Archibald Worwui
- Medical Research Council Unit The Gambia at London School of Hygiene & Tropical Medicine, Fajara, The Gambia.,University of Antwerp, Antwerp, Belgium
| | - Musa Jawara
- Medical Research Council Unit The Gambia at London School of Hygiene & Tropical Medicine, Fajara, The Gambia.,University of Antwerp, Antwerp, Belgium
| | | | - Teun Bousema
- Department of Medical Microbology, Radboud Medical University, Nijmegen, The Netherlands
| | | | - Chris Drakeley
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK
| | - Umberto D'Alessandro
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK.,Medical Research Council Unit The Gambia at London School of Hygiene & Tropical Medicine, Fajara, The Gambia.,University of Antwerp, Antwerp, Belgium
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Zhao Y, Zeng J, Zhao Y, Liu Q, He Y, Zhang J, Yang Z, Fan Q, Wang Q, Cui L, Cao Y. Risk factors for asymptomatic malaria infections from seasonal cross-sectional surveys along the China-Myanmar border. Malar J 2018; 17:247. [PMID: 29973194 PMCID: PMC6032786 DOI: 10.1186/s12936-018-2398-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 06/22/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Border malaria, a shared phenomenon in the Greater Mekong Sub-region of Southeast Asia, is a major obstacle for regional malaria elimination. Along the China-Myanmar border, an additional problem arose as a result of the settlement of internally displaced people (IDP) in the border region. Since asymptomatic malaria significantly impacts transmission dynamics, assessment of the prevalence, dynamics and risk factors of asymptomatic malaria infections is necessary. METHODS Cross-sectional surveys were carried out in 3 seasons (March and April, July and November) and 2 sites (villages and IDP camps) in 2015. A total of 1680 finger-prick blood samples were collected and used for parasite detection by microscopy and nested RT-PCR (nRT-PCR). Logistic regression models were used to explore the risk factors associated with asymptomatic malaria at individual and household levels. RESULTS The prevalence of asymptomatic Plasmodium infections was 23.3% by nRT-PCR, significantly higher than that detected by microscopy (1.5%). The proportions of Plasmodium vivax, Plasmodium falciparum and mixed-species infections were 89.6, 8.1 and 2.3%, respectively. Asymptomatic infections showed obvious seasonality with higher prevalence in the rainy season. Logistic regression analysis identified males and school children (≤ 15 years) as the high-risk populations. Vector-based interventions, including bed net and indoor residual spray, were found to have significant impacts on asymptomatic Plasmodium infections, with non-users of these measures carrying much higher risks of infection. In addition, individuals living in poorly constructed households or farther away from clinics were more prone to asymptomatic infections. CONCLUSIONS Sub-microscopic Plasmodium infections were highly prevalent in the border human populations from IDP camps and surrounding villages. Both individual- and household-level risk factors were identified, which provides useful information for identifying the high-priority populations to implement targeted malaria control.
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Affiliation(s)
- Yan Zhao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Jie Zeng
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Yonghong Zhao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Qingyang Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Yang He
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Jiaqi Zhang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Qinghui Wang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China.
| | - Liwang Cui
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China. .,Department of Entomology, Pennsylvania State University, University Park, State College, PA, 16802, USA.
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China.
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Wang XX, Cheng W, Yu Z, Liu SL, Mao HY, Chen EF. Risk factors for avian influenza virus in backyard poultry flocks and environments in Zhejiang Province, China: a cross-sectional study. Infect Dis Poverty 2018; 7:65. [PMID: 29914558 PMCID: PMC6006748 DOI: 10.1186/s40249-018-0445-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 05/30/2018] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Human infection of avian influenza virus (AIV) remains a great concern. Although live poultry markets are believed to be associated with human infections, ever more infections have been reported in rural areas with backyard poultry, especially in the fifth epidemic of H7N9. However, limited information is available on backyard poultry infection and surrounding environmental contamination. METHODS Two surveillance systems and a field survey were used to collect data and samples in Zhejiang Province. In total, 4538 samples were collected by surveillance systems and 3171 from the field survey between May 2015 and May 2017, while 352 backyard poultry owners were interviewed in May 2017 by questionnaire to investigate factors influencing the prevalence of avian influenza A virus and other AIV subtypes. RT-PCR was used to test the nucleic acids of viruses. ArcGIS 10.1 software was used to generate maps. Univariate and logistic regression analyses were conducted to identify risk factors for AIV infection. RESULTS Of the 428 poultry premises observed by the surveillance system, 53 (12.38%) were positive for influenza A virus. Of the 352 samples from poultry premises observed by field survey, 13 (3.39%) were positive for influenza A virus. The prevalence of AIV was unevenly distributed and the dominant subtype differed among cities. Eastern (Shaoxing and Ningbo) and southern (Wenzhou) cities exhibited a higher prevalence of AIV (16.33, 8.94, and 7.30% respectively). Contamination of AIV subtypes was most severe in January, especially in 2016 (23.26%, 70/301). The positive rate of subtype H5/H7/H9 was 2.53% (115/4538). Subtype H5 was the least prevalent, while subtypes H7 and H9 had similar positivity rates (1.50 and 1.32% respectively). Poultry flocks and environmental samples had a similar prevalence of AIV (4.46% vs 5.06%). The type of live birds was a risk factor and the sanitary condition of the setting was a protective factor against influenza A contamination. CONCLUSIONS AIV subtypes were prevalent in backyard poultry flocks and surrounding environments in Zhejiang Province. The types of live birds and sanitary conditions of the environment were associated with influenza A contamination. These findings shine a light on the characteristics of contamination of AIV subtypes and emphasize the importance of reducing AIV circulation in backyard poultry settings.
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Affiliation(s)
- Xiao-Xiao Wang
- Zhejiang Provincial Centre for Disease Control and Prevention, 3399 Binsheng Road, Binjiang District, Hangzhou, Zhejiang 310051 People’s Republic of China
| | - Wei Cheng
- Zhejiang Provincial Centre for Disease Control and Prevention, 3399 Binsheng Road, Binjiang District, Hangzhou, Zhejiang 310051 People’s Republic of China
| | - Zhao Yu
- Zhejiang Provincial Centre for Disease Control and Prevention, 3399 Binsheng Road, Binjiang District, Hangzhou, Zhejiang 310051 People’s Republic of China
| | - She-Lan Liu
- Zhejiang Provincial Centre for Disease Control and Prevention, 3399 Binsheng Road, Binjiang District, Hangzhou, Zhejiang 310051 People’s Republic of China
| | - Hai-Yan Mao
- Zhejiang Provincial Centre for Disease Control and Prevention, 3399 Binsheng Road, Binjiang District, Hangzhou, Zhejiang 310051 People’s Republic of China
| | - En-Fu Chen
- Zhejiang Provincial Centre for Disease Control and Prevention, 3399 Binsheng Road, Binjiang District, Hangzhou, Zhejiang 310051 People’s Republic of China
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48
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Muchena G, Dube B, Chikodzore R, Pasipamire J, Murugasampillay S, Mberikunashe J. A review of progress towards sub-national malaria elimination in Matabeleland South Province, Zimbabwe (2011-2015): a qualitative study. Malar J 2018; 17:146. [PMID: 29615043 PMCID: PMC5883310 DOI: 10.1186/s12936-018-2299-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Accepted: 03/26/2018] [Indexed: 11/10/2022] Open
Abstract
Background Malaria remains a public health problem in Zimbabwe. However, malaria elimination has become a foreseeable prospect with Matabeleland South Province making significant gains towards halting local malaria transmission. This study reviews malaria elimination progress and challenges to date utilizing the World Health Organization’s Malaria Programme Review framework. Results Between 2011 and 2015, malaria incidence was less than one case per 1000 population at risk in all districts save for Beitbridge and Gwanda. The majority of cases were from Beitbridge with local transmission in the same. Incidence declined in Bulilima (p = 0.01), Gwanda (p = 0.72) and Umzingwane (p = 0.44), increasing in Beitbridge (p = 0.35), Insiza (p = 0.79) and Mangwe (p = 0.60). Overall provincial incidence declined although this was not statistically significant. Malaria transmission was bimodal, with a major peak in April and a minor peak in October. A case based malaria surveillance system existed but was not real-time. Foci response guidelines were not domesticated. Artemisinin formed the backbone of case management regimens with primaquine for gametocyte clearance. Indoor residual spraying coverages were below the national target of 95% for rooms targeted for spraying. Conclusion Matabeleland South province has set precedence for targeting sub-national malaria elimination in Zimbabwe. This experience may prove useful for national scale up. There is need to improve surveillance, foci response and intensification of activities to halt residual malaria transmission in Beitbridge District.
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Affiliation(s)
- Gladwin Muchena
- Ministry of Health and Child Care, P. Bag A5225, Matabeleland South Province, Bulawayo, Zimbabwe.
| | - Busisani Dube
- Ministry of Health and Child Care, National Malaria Control Programme, Harare, Zimbabwe
| | - Rudo Chikodzore
- Ministry of Health and Child Care, P. Bag A5225, Matabeleland South Province, Bulawayo, Zimbabwe
| | - Jasper Pasipamire
- World Health Organization, Zimbabwe Country Office, Harare, Zimbabwe
| | | | - Joseph Mberikunashe
- Ministry of Health and Child Care, National Malaria Control Programme, Harare, Zimbabwe
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49
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Deutsch-Feldman M, Hamapumbu H, Lubinda J, Musonda M, Katowa B, Searle KM, Kobayashi T, Shields TM, Stevenson JC, Thuma PE, Moss WJ, For The Southern Africa International Centers Of Excellence For Malaria Research. Efficiency of a Malaria Reactive Test-and-Treat Program in Southern Zambia: A Prospective, Observational Study. Am J Trop Med Hyg 2018; 98:1382-1388. [PMID: 29557330 DOI: 10.4269/ajtmh.17-0865] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
To improve malaria surveillance and achieve elimination, the Zambian National Malaria Elimination Program implemented a reactive test-and-treat program in Southern Province in 2013 in which individuals with rapid diagnostic test (RDT)-confirmed malaria are followed-up at their home within 1 week of diagnosis. Individuals present at the index case household and those residing within 140 m of the index case are tested with an RDT and treated with artemether-lumefantrine if positive. This study evaluated the efficiency of this reactive test-and-treat strategy by characterizing infected individuals missed by the RDT and the current screening radius. The radius was expanded to 250 m, and a quantitative polymerase chain reaction (qPCR) test was performed on dried blood spot specimens. From January 2015 through March 2016, 145 index cases were identified at health centers and health posts. A total of 3,333 individuals residing in 525 households were screened. Excluding index cases, the parasite prevalence was 1.1% by RDT (33 positives of 3,016 participants) and 2.4% by qPCR (73 positives of 3,016 participants). Of the qPCR-positive cases, 62% of 73 individuals tested negative by RDT. Approximately half of the infected individuals resided within the index case household (58% of RDT-positive individuals and 48% of qPCR-positive individuals). The low sensitivity of the RDT and the high proportion of secondary cases within the index case household decreased the efficiency of this reactive test-and-treat strategy. Reactive focal drug administration in index case households would be a more efficient approach to treating infected individuals associated with a symptomatic case.
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Affiliation(s)
- Molly Deutsch-Feldman
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina
| | | | | | | | - Ben Katowa
- Macha Research Trust, Choma District, Zambia
| | - Kelly M Searle
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
| | - Tamaki Kobayashi
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
| | - Timothy M Shields
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
| | - Jennifer C Stevenson
- Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland.,Macha Research Trust, Choma District, Zambia
| | - Philip E Thuma
- Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland.,Macha Research Trust, Choma District, Zambia
| | - William J Moss
- Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland.,Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
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50
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Reactive case detection of Plasmodium falciparum in western Kenya highlands: effective in identifying additional cases, yet limited effect on transmission. Malar J 2018. [PMID: 29534709 PMCID: PMC5851086 DOI: 10.1186/s12936-018-2260-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Background Identifying asymptomatic reservoirs of malaria parasites using index cases as entry points into the community is potentially a cost-effective way towards achieving malaria elimination. Methods Within 1 year, 1430 confirmed malaria cases were identified in Marani hospital, western Kenya. Fifty cases were followed up, and 108 index case household members and 612 neighbours within a 100 m radius were screened. As controls, samples were collected from 510 individuals matched with index cases and located at a distance of ≥ 500 m from them. Infections were diagnosed by microscopy and PCR while simultaneously collecting malaria vectors indoor using pyrethrum spray catches. Results In the index case and neighbour households, the prevalence of infection was approximately twice as high as in control households (by PCR: index cases households: 28.9%, neighbours: 25.3%, matched controls: 12.9%). In index case households, the indoor vector density (Anopheles gambiae and Anopheles funestus) was higher (0.46 female/house/night) than in neighbouring (0.31 f/h/n) and control houses (0.29 f/h/n). Conclusions Screening index case households and neighbours approximately doubles the chance to detect asymptomatic infections compared to randomly selected households. However, even if all cases were followed up, only a small proportion (˂ 10%) of the asymptomatic reservoir in the population would have been identified. Control programmes need to weigh the increased chance to find cases around index cases vs. the logistical challenges to target this subgroup within the population.
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