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Deen J, Mukaka M, von Seidlein L. What is the yield of malaria reactive case detection in the Greater Mekong Sub-region? A review of published data and meta-analysis. Malar J 2021; 20:131. [PMID: 33663484 PMCID: PMC7934542 DOI: 10.1186/s12936-021-03667-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Accepted: 02/24/2021] [Indexed: 01/01/2023] Open
Abstract
Background Reactive malaria case detection involves the screening of those in contact with index cases and is used in countries in the Greater Mekong Sub-region. The yield of reactive case detection, defined here as the percentage of positive malaria cases among potential contacts who were screened, was assessed. Methods A literature search was conducted on PubMed to identify studies on reactive case detection in the Greater Mekong Sub-region. Eligible published articles were reviewed and pooled estimates from the studies were calculated, by type of malaria test used. Results Eighty-five publications were retrieved, of which 8 (9.4%) eligible articles were included in the analysis. The yield from reactive case detection ranged from 0.1 to 4.2%, with higher rates from PCR testing compared with microscopy and/or rapid diagnostic test. The overall yield from microscopy and/or rapid diagnostic test was 0.56% (95% CI 0.31–0.88%), while that from PCR was 2.35% (95% CI 1.19–3.87%). The two studies comparing different target groups showed higher yield from co-workers/co-travellers, compared with household contacts. Conclusion In low malaria transmission settings, the effectiveness of reactive case detection is diminishing. In the Greater Mekong Sub-region, modifying reactive case detection from household contacts to co-workers/co-travellers and from testing to presumptive treatment of targeted contacts, could increase the impact of this approach.
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Affiliation(s)
- Jacqueline Deen
- Institute of Child Health and Human Development, National Institutes of Health, University of the Philippines, 623 P. Gil St, 1000, Manila, Philippines.
| | - Mavuto Mukaka
- Faculty of Tropical Medicine, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Lorenz von Seidlein
- Faculty of Tropical Medicine, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
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Acquah FK, Donu D, Obboh EK, Bredu D, Mawuli B, Amponsah JA, Quartey J, Amoah LE. Diagnostic performance of an ultrasensitive HRP2-based malaria rapid diagnostic test kit used in surveys of afebrile people living in Southern Ghana. Malar J 2021; 20:125. [PMID: 33653356 PMCID: PMC7927401 DOI: 10.1186/s12936-021-03665-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 02/24/2021] [Indexed: 12/14/2022] Open
Abstract
Background The Alere™ Malaria Ag P.f Ultra-sensitive RDT (UsmRDT) kit is an HRP2-based malaria rapid diagnostic test (RDT) with enhanced sensitivity relative to the SD Bioline Malaria Ag P.f RDT (mRDT) kit. However, the diagnostic performance of the UsmRDT kit has not been evaluated in Ghana. Methods A total of 740 afebrile participants aged between 3 and 88 years old were recruited from the Central and Greater Accra Regions of Ghana during the off-peak malaria season. Axillary body temperature was measured, and a volume of 1 ml venous blood was drawn from each participant. Prior to separating the blood into plasma and packed cell pellets via centrifugation, the blood was spotted onto one UsmRDT and one mRDT kit and also used to prepare thick and thin blood smears as well as filter paper blood spots. Plasmodium falciparum specific polymerase chain reaction (PCR) was performed on gDNA extracted from 100 µl of the whole blood. Results The overall positivity rate for microscopy, PCR, UsmRDT and mRDT kit were 20.4%, 40.8%, 31.3% and 30.8%, respectively. Overall, the UsmRDT identified 9.3% (28/302) more PCR positive samples than the mRDT kits. All samples that were negative by the UsmRDT kit were also negative by the mRDT kit. Overall, the sensitivity and specificity of the UsmRDT was 73% (221/302) and 89% (388/436), respectively, while that for the mRDT kit was 58% and 90%, respectively. Conclusion Although the UsmRDT kit was not as sensitive as PCR at detecting asymptomatic P. falciparum carriage, it correctly identified P. falciparum in 9.3% of the study participants that were not captured by the mRDT kit. In malaria endemic settings, the UsmRDT would provide an added advantage by identifying more asymptomatic P. falciparum carriers than the mRDT kit for targeted treatment interventions.
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Affiliation(s)
- Festus K Acquah
- Immunology Department, Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana, Accra, Ghana.,West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
| | - Dickson Donu
- Immunology Department, Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana, Accra, Ghana
| | - Evans K Obboh
- School of Medical Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Dorcas Bredu
- Immunology Department, Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana, Accra, Ghana
| | - Bernice Mawuli
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
| | - Jones A Amponsah
- Immunology Department, Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana, Accra, Ghana
| | - Joseph Quartey
- Parasitology Department, Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana, Accra, Ghana
| | - Linda E Amoah
- Immunology Department, Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana, Accra, Ghana. .,West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana.
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53
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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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54
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Christensen P, Bozdech Z, Watthanaworawit W, Imwong M, Rénia L, Malleret B, Ling C, Nosten F. Reverse transcription PCR to detect low density malaria infections. Wellcome Open Res 2021; 6:39. [PMID: 35592834 PMCID: PMC9086519 DOI: 10.12688/wellcomeopenres.16564.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/05/2021] [Indexed: 05/14/2024] Open
Abstract
Background: Targeted malaria elimination strategies require highly sensitive tests to detect low density malaria infections (LDMI). Commonly used methods for malaria diagnosis such as light microscopy and antigen-based rapid diagnostic tests (RDTs) are not sensitive enough for reliable identification of infections with parasitaemia below 200 parasites per milliliter of blood. While targeted malaria elimination efforts on the Thailand-Myanmar border have successfully used high sample volume ultrasensitive quantitative PCR (uPCR) to determine malaria prevalence, the necessity for venous collection and processing of large quantities of patient blood limits the widespread tractability of this method. Methods: Here we evaluated a real-time reverse transcription PCR (RT-PCR) method that reduces the required sample volume compared to uPCR. To do this, 304 samples collected from an active case detection program in Kayin state, Myanmar were compared using uPCR and RT-PCR. Results: Plasmodium spp. RT-PCR confirmed 18 of 21 uPCR Plasmodium falciparum positives, while P. falciparum specific RT-PCR confirmed 17 of the 21 uPCR P. falciparum positives. Combining both RT-PCR results increased the sensitivity to 100% and specificity was 95.1%. Conclusion: Malaria detection in areas of low transmission and LDMI can benefit from the increased sensitivity of ribosomal RNA detection by RT-PCR, especially where sample volume is limited. Isolation of high quality RNA also allows for downstream analysis of malaria transcripts.
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Affiliation(s)
- Peter Christensen
- Shoklo Malaria Research Unit, Mahidol University, Maesot, Tak, 63110, Thailand
- Microbiology and Immunology, University of Otago, Dunedin, Otago, 9016, New Zealand
| | - Zbynek Bozdech
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | | | - Mallika Imwong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Thailand
| | - Laurent Rénia
- Singapore Immunology Network, A*STAR, Singapore, 138648, Singapore
- A*STAR ID Labs, A*STAR, Singapore, 138648, Singapore
| | - Benoît Malleret
- Singapore Immunology Network, A*STAR, Singapore, 138648, Singapore
- Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545, Singapore
| | - Clare Ling
- Shoklo Malaria Research Unit, Mahidol University, Maesot, Tak, 63110, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - François Nosten
- Shoklo Malaria Research Unit, Mahidol University, Maesot, Tak, 63110, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
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55
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Shankar H, Phookan S, Singh MP, Bharti RS, Ahmed N, Yadav CP, Sharma GP, Singh K, Kaur H, Mishra N. Asymptomatic low-density Plasmodium infection during non-transmission season: a community-based cross-sectional study in two districts of North Eastern Region, India. Trans R Soc Trop Med Hyg 2021; 115:1198-1206. [PMID: 33580962 DOI: 10.1093/trstmh/trab017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 05/25/2020] [Accepted: 01/19/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Malaria elimination requires targeting asymptomatic and low-density Plasmodium infections that largely remain undetected. Therefore we conducted a cross-sectional study to estimate the burden of asymptomatic and low-density Plasmodium infection using conventional and molecular diagnostics. METHODS A total of 9118 participants, irrespective of age and sex, were screened for malaria using rapid diagnostic tests (RDTs), microscopy and polymerase chain reaction. RESULTS Among the participants, 707 presented with symptoms and 8411 without symptoms, of which Plasmodium was present in 15.6% (110/707) and 8.1% (681/8411), respectively. Low-density infection was found in 5.1% (145/2818) of participants and 8327 of 9118 were Plasmodium negative. Endemicity was propotional to asymptomatic infections (high endemicity 11.1% [404/3633] vs low endemicity 5.8% [277/4778]; odds ratio [OR] 2.0 [95% confidence interval {CI} 1.7 to 2.4]) but inversely related to low-density infection (high endemicity 3.7% [57/1545] vs low endemicity 6.9% [88/1273]; OR 1.9 [95% CI 1.4 to 2.7]). The spleen rate in children 2-9 y of age was 17.9% (602/3368) and the enlarged spleen index was 1.6. Children between 8 and 14 y showed higher odds for asymptomatic (adjusted OR [aOR] 1.75 [95% CI 1.4 to 2.2]) and low-density infections (aOR 0.63 [95% CI 0.4 to 1.0)] than adults. CONCLUSIONS The prevalence of asymptomatic and low-density Plasmodium infection undermines the usefulness of standard diagnostic tools used by health agencies. This necessitates deploying molecular tools in areas where malaria microscopy/RDTs indicate a dearth of infection.
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Affiliation(s)
- Hari Shankar
- Indian Council of Medical Research-National Institute of Malaria Research, Sector-8, Dwarka, New Delhi 110077, India
| | - Sobhan Phookan
- Indian Council of Medical Research-National Institute of Malaria Research Field Unit, Guwahati 781022, Assam, India
| | - Mrigendra Pal Singh
- Indian Council of Medical Research-National Institute of Malaria Research Field Unit, Jabalpur 482003, Madhya Pradesh, India
| | - Ram Suresh Bharti
- Indian Council of Medical Research-National Institute of Malaria Research, Sector-8, Dwarka, New Delhi 110077, India
| | - Naseem Ahmed
- Indian Council of Medical Research-National Institute of Malaria Research, Sector-8, Dwarka, New Delhi 110077, India
| | - Chander Prakash Yadav
- Indian Council of Medical Research-National Institute of Malaria Research, Sector-8, Dwarka, New Delhi 110077, India
| | - Guru Prasad Sharma
- Indian Council of Medical Research-National Institute of Malaria Research, Sector-8, Dwarka, New Delhi 110077, India
| | - Kuldeep Singh
- Indian Council of Medical Research-National Institute of Malaria Research Field Unit, Guwahati 781022, Assam, India
| | - Harpreet Kaur
- Indian Council of Medical Research, Ansari Nagar, New Delhi 110029, India
| | - Neelima Mishra
- Indian Council of Medical Research-National Institute of Malaria Research, Sector-8, Dwarka, New Delhi 110077, India
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Genotyping cognate Plasmodium falciparum in humans and mosquitoes to estimate onward transmission of asymptomatic infections. Nat Commun 2021; 12:909. [PMID: 33568678 PMCID: PMC7875998 DOI: 10.1038/s41467-021-21269-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 01/15/2021] [Indexed: 01/30/2023] Open
Abstract
Malaria control may be enhanced by targeting reservoirs of Plasmodium falciparum transmission. One putative reservoir is asymptomatic malaria infections and the scale of their contribution to transmission in natural settings is not known. We assess the contribution of asymptomatic malaria to onward transmission using a 14-month longitudinal cohort of 239 participants in a high transmission site in Western Kenya. We identify P. falciparum in asymptomatically- and symptomatically-infected participants and naturally-fed mosquitoes from their households, genotype all parasites using deep sequencing of the parasite genes pfama1 and pfcsp, and use haplotypes to infer participant-to-mosquito transmission through a probabilistic model. In 1,242 infections (1,039 in people and 203 in mosquitoes), we observe 229 (pfcsp) and 348 (pfama1) unique parasite haplotypes. Using these to link human and mosquito infections, compared with symptomatic infections, asymptomatic infections more than double the odds of transmission to a mosquito among people with both infection types (Odds Ratio: 2.56; 95% Confidence Interval (CI): 1.36-4.81) and among all participants (OR 2.66; 95% CI: 2.05-3.47). Overall, 94.6% (95% CI: 93.1-95.8%) of mosquito infections likely resulted from asymptomatic infections. In high transmission areas, asymptomatic infections are the major contributor to mosquito infections and may be targeted as a component of transmission reduction.
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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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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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Lee SK, Hu F, Firdaus ER, Park JH, Han JH, Lee SE, Shin HI, Cho SH, Park WS, Lu F, Han ET. Surveillance on the Vivax Malaria in Endemic Areas in the Republic of Korea Based on Molecular and Serological Analyses. THE KOREAN JOURNAL OF PARASITOLOGY 2020; 58:609-617. [PMID: 33412764 PMCID: PMC7806437 DOI: 10.3347/kjp.2020.58.6.609] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 11/02/2020] [Indexed: 11/23/2022]
Abstract
Plasmodium vivax reemerged in 1993. It has been sustained for more than 25 years and become one of the important indigenous parasitic diseases in northern and western parts of the Republic of Korea near the demilitarized zone. In particular, relapse is a significant concern for the control of malaria, as short- and long-term incubation periods vary among those infected in Korea. In this study, the prevalence of asymptomatic carriers was examined among residents of high endemic areas of vivax malaria during nonseasonal transmission of mosquitoes. Blood samples from 3 endemic regions in northwestern Korea were evaluated by microscopic examination, rapid diagnostic testing, and nested PCR to identify asymptomatic patients carrying malaria parasites in the community. However, no positive malaria case among residents of endemic areas was detected. Additionally, serological analysis was carried out to measure antibodies against 3 antigenic recombinant proteins of P. vivax, merozoite surface protein 1-19, circumsporozoite surface protein-VK210, and liver-stage antigen (PvLSA-N), by the protein array method. Interestingly, seropositivity of sera between previous exposure and samples without exposure to malaria was significantly higher using the PvLSA-N antigen than the other antigens, suggesting that PvLSA-N can be used as a serological marker to analyze the degree of exposure for malaria transmission in endemic areas. This indicates a very low asymptomatic carrier prevalence during the nonmalaria season in the endemic areas of Korea.
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Affiliation(s)
- Seong-Kyun Lee
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, Korea
| | - Fengyue Hu
- Department of Pathogenic Biology, School of Medicine, Yangzhou University, Yangzhou, Jiangsu 225000, China
| | - Egy Rahman Firdaus
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, Korea
| | - Ji-Hoon Park
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, Korea
| | - Jin-Hee Han
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, Korea
| | - Sang-Eun Lee
- Division of Vectors and Parasitic Diseases, Bureau of Infectious Disease Diagnosis Control, Korea Disease Control and Prevention Agency, Chungbuk 28159, Korea
| | - Hyun-Il Shin
- Division of Vectors and Parasitic Diseases, Bureau of Infectious Disease Diagnosis Control, Korea Disease Control and Prevention Agency, Chungbuk 28159, Korea
| | - Shin Hyeong Cho
- Division of Vectors and Parasitic Diseases, Bureau of Infectious Disease Diagnosis Control, Korea Disease Control and Prevention Agency, Chungbuk 28159, Korea
| | - Won Sun Park
- Department of Physiology, School of Medicine, Kangwon National University, Chuncheon 24341, Korea
| | - Feng Lu
- Department of Pathogenic Biology, School of Medicine, Yangzhou University, Yangzhou, Jiangsu 225000, China
| | - Eun-Taek Han
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, Korea
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Targeting Malaria Hotspots to Reduce Transmission Incidence in Senegal. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 18:ijerph18010076. [PMID: 33374228 PMCID: PMC7796302 DOI: 10.3390/ijerph18010076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 11/16/2022]
Abstract
In central Senegal, malaria incidence declined in response to scaling-up of control measures from 2000 to 2010 and has since remained stable, making elimination unlikely in the short term. Additional control measures are needed to reduce transmission. We simulated chemoprophylaxis interventions targeting malaria hotspots using a metapopulation mathematical model, based on a differential-equation framework and incorporating human mobility. The model was fitted to weekly malaria incidence from 45 villages. Three approaches for selecting intervention targets were compared: (a) villages with malaria cases during the low transmission season of the previous year; (b) villages with highest incidence during the high transmission season of the previous year; (c) villages with highest connectivity with adjacent populations. Our results showed that intervention strategies targeting hotspots would be effective in reducing malaria incidence in both targeted and untargeted areas. Regardless of the intervention strategy used, pre-elimination (1-5 cases per 1000 per year) would not be reached without simultaneously increasing vector control by more than 10%. A cornerstone of malaria control and elimination is the effective targeting of strategic locations. Mathematical tools help to identify those locations and estimate the impact in silico.
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Monnier N, Barth-Jaeggi T, Knopp S, Steinmann P. Core components, concepts and strategies for parasitic and vector-borne disease elimination with a focus on schistosomiasis: A landscape analysis. PLoS Negl Trop Dis 2020; 14:e0008837. [PMID: 33125375 PMCID: PMC7598467 DOI: 10.1371/journal.pntd.0008837] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 10/01/2020] [Indexed: 12/19/2022] Open
Abstract
Efforts to control and eliminate human schistosomiasis have accelerated over the past decade. In a number of endemic countries and settings, interruption of schistosome transmission has been achieved. In others, Schistosoma infections continue to challenge program managers at different levels, from the complexity of the transmission cycle, over limited treatment options and lack of field-friendly accurate diagnostics, to controversy around adequate intervention strategies. We conducted a landscape analysis on parasitic and vector-borne disease elimination approaches with the aim to identify evidence-based strategies, core components and key concepts for achieving and sustaining schistosomiasis control and for progressing elimination efforts towards interruption of transmission in sub-Saharan Africa. A total of 118 relevant publications were identified from Web of Science, Pubmed and the grey literature and reviewed for their content. In addition, we conducted in-depth interviews with 23 epidemiologists, program managers, policymakers, donors and field researchers. Available evidence emphasizes the need for comprehensive, multipronged and long-term strategies consisting of multiple complementary interventions that must be sustained over time by political commitment and adequate funding in order to reach interruption of transmission. Based on the findings of this landscape analysis, we propose a comprehensive set of intervention strategies for schistosomiasis control and elimination. Before deployment, the proposed interventions will require review, evaluation and validation in the frame of an expert consultation as a step towards adaptation to specific contexts, conditions and settings. Field testing to ensure local relevance and effectiveness is paramount given the diversity of socio-ecological and epidemiological contexts. This landscape analysis explored successful concepts, approaches and interventions of past and ongoing parasitic and vector-borne disease elimination efforts and programs with regard to relevance for progress in the elimination of human schistosome infections. Schistosomiasis is a disabling, water borne parasitic disease of public health concern with an estimated 250 million people infected worldwide. The long-term morbidity of this neglected tropical disease significantly impacts growth, cognition and socioeconomic development at all ages. Despite increased global efforts to control morbidity and advance elimination, challenges in view of the complex life cycle which involves freshwater sources, intermediate snail hosts and humans, remain. This calls for targeted interventions and concerted programs. According to the evidence from the literature and as proposed by a wide range of key informants, comprehensive, multipronged and long-term strategies supported by strong political commitment and adequate funding are required in order to achieve and sustain the set goals. Based on the findings, we propose here a comprehensive set of intervention strategies for schistosomiasis control and elimination for review and evaluation to inform implementation research needs and elimination program design.
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Affiliation(s)
- Nora Monnier
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- * E-mail:
| | - Tanja Barth-Jaeggi
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Stefanie Knopp
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Peter Steinmann
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
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Hamre KES, Hodges JS, Ayodo G, John CC. Lack of Consistent Malaria Incidence Hotspots in a Highland Kenyan Area During a 10-Year Period of Very Low and Unstable Transmission. Am J Trop Med Hyg 2020; 103:2198-2207. [PMID: 33124534 DOI: 10.4269/ajtmh.19-0821] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The use of spatial data in malaria elimination strategies is important to understand whether targeted interventions against malaria can be used, particularly in areas with limited resources. We previously documented consistent areas of increased malaria incidence in the epidemic-prone area of Kipsamoite in highland Kenya from 2001 to 2004. In this area and a neighboring subcounty (Kapsisiywa), malaria incidence decreased substantially in 2005, going from peak incidence of 31.7 per 1,000 persons in June 2004 to peak incidence of 7.4 per 1,000 persons in May 2005. Subsequently, the use of indoor residual spraying and artemisinin combination therapy malaria treatment led to a possible interruption of malaria transmission for a 13-month period from 2007 to 2008, after which the incidence returned to very low levels until an epidemic in April-July 2013. In the present study, we used novel kernel density estimation methods to determine whether areas of increased malaria incidence were consistent in six periods of peak incidence from 2003 to 2013, and to assess patterns of incidence in the period before versus. after the period of possible interruption. Areas of highest incidence differed during peak malaria transmission periods over the years 2003-2013, and differed before and after the potential malaria interruption. In this epidemic-prone region with very low malaria transmission, consistent malaria "hotspots" identified in a time of higher transmission are no longer present. Ongoing assessment of spatial malaria epidemiology to identify and target current areas of elevated malaria risk may be important in campaigns to control or eliminate malaria in epidemic-prone areas.
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Affiliation(s)
- Karen E S Hamre
- CDC Foundation, Atlanta, Georgia.,Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, Minnesota.,Division of Global Pediatrics, University of Minnesota, Minneapolis, Minnesota
| | - James S Hodges
- Division of Biostatistics, University of Minnesota, Minneapolis, Minnesota
| | - George Ayodo
- Jaramogi Oginga Odinga University of Science and Technology, Bondo, Kenya.,Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Chandy C John
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.,Division of Global Pediatrics, University of Minnesota, Minneapolis, Minnesota.,Department of Pediatrics, Indiana University, Indianapolis, Indiana.,Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, Minnesota
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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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Large Variations in Malaria Parasite Carriage by Afebrile School Children Living in Nearby Communities in the Central Region of Ghana. J Trop Med 2020; 2020:4125109. [PMID: 33029151 PMCID: PMC7528039 DOI: 10.1155/2020/4125109] [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: 03/26/2020] [Revised: 06/25/2020] [Accepted: 09/03/2020] [Indexed: 02/08/2023] Open
Abstract
Background Indicators of successful malaria control interventions include a reduction in the prevalence and densities of malaria parasites contained in both symptomatic and asymptomatic infections as well as a reduction in malaria transmission. Individuals harboring malaria parasites in asymptomatic infections serve as reservoirs for malaria transmission. This study determined the prevalence of asymptomatic malaria parasite carriage in afebrile children attending six different schools in two districts, the Cape Coast Metropolitan Assembly (CCMA) and the Komenda Edina Eguafo Abirem (KEEA) of the Central Region of Ghana. Methods This cross sectional study recruited afebrile children aged between 3 and 15 years old from six randomly selected schools in the Central Region of Ghana. Finger-pricked blood was collected and used to prepare thick and thin blood smears as well as spot a strip of filter paper (Whatman #3). Nested PCR was used to identify Plasmodium falciparum, Plasmodium malariae, Plasmodium ovale, and Plasmodium vivax in DNA extracted from the filter paper spots. The multiplicity of P. falciparum infection was determined using merozoite surface protein 2 genotyping. Results Out of the 528 children sampled, PCR identified 27.1% to harbor Plasmodium parasites in asymptomatic infections, whilst microscopy identified malaria parasites in 10.6% of the children. The overall PCR estimated prevalence of P. falciparum and P. malariae was 26.6% and 1.3%, respectively, with no P. ovale or P. vivax identified by PCR or microscopy. The RDT positivity rate ranged from 55.8% in Simiw to 4.5% in Kuful. Children from the Simiw Basic School accounted for 87.5% of all the asymptomatic infections. The multiplicity of P. falciparum infection was predominantly monoclonal and biclonal. Conclusions The low prevalence of asymptomatic malaria parasite carriage by the children living in the Cape Coast Metropolis suggests that the malaria control interventions in place in CCMA are highly effective and that additional malaria control interventions are required for the KEEA district to reduce the prevalence of asymptomatic malaria parasite carriers. No molecular evidence of P. ovale and P. vivax was identified in the afebrile children sampled from the selected schools.
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65
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Ajayi IO, Ajumobi OO, Falade C. Malaria and COVID-19: commonalities, intersections and implications for sustaining malaria control. Pan Afr Med J 2020; 37:1. [PMID: 33294102 PMCID: PMC7704348 DOI: 10.11604/pamj.supp.2020.37.1.25738] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 08/31/2020] [Indexed: 11/25/2022] Open
Abstract
The devastating impact of infectious disease outbreaks and pandemics on health systems could be overwhelming especially when there is an overlap in clinical presentations with other disease conditions. A case in point is the disruptive effect of the Ebola Virus Disease outbreak on health service delivery and its consequences for malaria management in the affected West and Central African countries between 2014 and 2016. This could be the case with the current infectious disease pandemic (COVID-19) the world is experiencing as malaria illness shares many symptoms with COVID-19 illness. Caused by a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), COVID-19 is reported to have originated from Wuhan city, China in December 2019. COVID-19 was declared a Public Health Emergency of International Concern on 30 January 2020 and declared a pandemic on March 11, 2020 by the World Health Organization (WHO). Practically, all community infrastructure has been activated in affected countries in response to COVID-19. However, the deployment of huge resources in combating COVID-19 pandemic should not be a missed opportunity for the advancement of infectious diseases control including malaria. This calls for conscious and heightened effort to sustain the gains in malaria control. The WHO has emphasized that the response to the COVID-19 pandemic must utilize and strengthen existing infrastructure for addressing malaria and other infectious diseases globally. Leveraging these to maintain malaria control activities in endemic countries could boost and help to sustain the gains in malaria control in accordance with the 2016-2030 Global technical strategy for malaria (GTS) milestones. In addition, it will help to keep the “High burden to high impact” (HBHI) and other initiatives on track. This article highlights the commonalities of the two diseases, discusses implications and recommendations to support decision making strategies to keep malaria control on track in the COVID-19 pandemic era.
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Affiliation(s)
- IkeOluwapo Oyeneye Ajayi
- Department of Epidemiology and Medical Statistics, College of Medicine, University of Ibadan, Ibadan, Nigeria.,Epidemiology and Biostatistics Research Unit, Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - Olufemi Olamide Ajumobi
- School of Community Health Sciences, University of Nevada, Reno; Reno, USA.,National Malaria Elimination Programme, Federal Ministry of Health, Abuja, Nigeria
| | - Catherine Falade
- Department of Pharmacology & Therapeutics, College of Medicine, University of Ibadan, Ibadan, Nigeria
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66
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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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Christofferson RC, Parker DM, Overgaard HJ, Hii J, Devine G, Wilcox BA, Nam VS, Abubakar S, Boyer S, Boonnak K, Whitehead SS, Huy R, Rithea L, Sochantha T, Wellems TE, Valenzuela JG, Manning JE. Current vector research challenges in the greater Mekong subregion for dengue, Malaria, and Other Vector-Borne Diseases: A report from a multisectoral workshop March 2019. PLoS Negl Trop Dis 2020; 14:e0008302. [PMID: 32730249 PMCID: PMC7392215 DOI: 10.1371/journal.pntd.0008302] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Affiliation(s)
- Rebecca C. Christofferson
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Daniel M. Parker
- University of California, Irvine, California, United States of America
| | | | | | - Gregor Devine
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Bruce A. Wilcox
- ASEAN Institute for Health Development, Mahidol University, Nakhon Pathom, Thailand
| | - Vu Sinh Nam
- National Institute of Hygiene and Epidemiology, Hanoi, Vietnam
| | - Sazaly Abubakar
- Tropical Infectious Diseases Research and Education Center, Kuala Lumpur, Malaysia
| | | | - Kobporn Boonnak
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Stephen S. Whitehead
- National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, United States of America
| | - Rekol Huy
- National Center for Parasitology Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Leang Rithea
- National Center for Parasitology Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Tho Sochantha
- National Center for Parasitology Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Thomas E. Wellems
- National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, United States of America
| | - Jesus G. Valenzuela
- National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, United States of America
| | - Jessica E. Manning
- US National Institute of Allergy and Infectious Diseases, Phnom Penh, Cambodia
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The Importance of an Active Case Detection (ACD) Programme for Malaria among Migrants from Malaria Endemic Countries: The Greek Experience in a Receptive and Vulnerable Area. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17114080. [PMID: 32521653 PMCID: PMC7312366 DOI: 10.3390/ijerph17114080] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 05/26/2020] [Accepted: 06/04/2020] [Indexed: 11/23/2022]
Abstract
Greece has been malaria-free since 1974. In October 2011, following an outbreak of 36 locally acquired malaria (LAM) cases in Evrotas Municipality, a Pro-Active Case Detection (PACD) program for malaria was implemented among migrants from malaria-endemic countries, to support early diagnosis and treatment of cases. We evaluated the PACD program for the years 2012–2017 using indicators such as the number of locally acquired cases, the detection rate/sensitivity and the timeliness of diagnosis and treatment. We visited each migrant home every 7–15 days to screen migrants for malaria symptoms, performing Rapid Diagnostic Tests (RDTs) and blood smears on symptomatic patients. We estimated: (i) the number of malaria cases detected by the PACD, divided by the total number of reported malaria cases during the same period among the same population; (ii) the time between onset of symptoms, diagnosis and initiation of treatment. The total number of migrants who were screened for malaria symptoms for the years 2012–2017 was 5057 with 84,169 fever screenings conducted, while 2288 RDTs and 1736 blood smears were performed. During the same period, 53 imported P. vivax malaria cases were detected, while incidence of malaria among migrants was estimated at 1.8% annually. Ten and one LAM cases were also reported in 2012 and 2015, respectively. Sensitivity of PACD ranged from 86% to 100%; median timeliness between onset of symptoms and diagnosis decreased from 72 h in 2012 to 12 h in 2017 (83% decrease), while timeliness between diagnosis and treatment initiation was 0 h. The implementation of PACD could be considered an effective prevention and response tool against malaria re-introduction.
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70
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Alegana VA, Okiro EA, Snow RW. Routine data for malaria morbidity estimation in Africa: challenges and prospects. BMC Med 2020; 18:121. [PMID: 32487080 PMCID: PMC7268363 DOI: 10.1186/s12916-020-01593-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 04/14/2020] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND The burden of malaria in sub-Saharan Africa remains challenging to measure relying on epidemiological modelling to evaluate the impact of investments and providing an in-depth analysis of progress and trends in malaria response globally. In malaria-endemic countries of Africa, there is increasing use of routine surveillance data to define national strategic targets, estimate malaria case burdens and measure control progress to identify financing priorities. Existing research focuses mainly on the strengths of these data with less emphasis on existing challenges and opportunities presented. CONCLUSION Here we define the current imperfections common to routine malaria morbidity data at national levels and offer prospects into their future use to reflect changing disease burdens.
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Affiliation(s)
- Victor A Alegana
- Population Health Unit, Kenya Medical Research Institute - Wellcome Trust Research Programme, P.O. Box 43640, Nairobi, 00100, Kenya.
- Geography and Environmental Science, University of Southampton, Southampton, SO17 1BJ, UK.
- Faculty of Science and Technology, Lancaster University, Lancaster, LAI 4YW, UK.
| | - Emelda A Okiro
- Population Health Unit, Kenya Medical Research Institute - Wellcome Trust Research Programme, P.O. Box 43640, Nairobi, 00100, Kenya
| | - Robert W Snow
- Population Health Unit, Kenya Medical Research Institute - Wellcome Trust Research Programme, P.O. Box 43640, Nairobi, 00100, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, OX3 7LJ, UK
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How to Estimate Optimal Malaria Readiness Indicators at Health-District Level: Findings from the Burkina Faso Service Availability and Readiness Assessment (SARA) Data. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17113923. [PMID: 32492901 PMCID: PMC7312483 DOI: 10.3390/ijerph17113923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 05/26/2020] [Accepted: 05/28/2020] [Indexed: 12/25/2022]
Abstract
One of the major contributors of malaria-related deaths in Sub-Saharan African countries is the limited accessibility to quality care. In these countries, malaria control activities are implemented at the health-district level (operational entity of the national health system), while malaria readiness indicators are regionally representative. This study provides an approach for estimating health district-level malaria readiness indicators from survey data designed to provide regionally representative estimates. A binomial-hierarchical Bayesian spatial prediction method was applied to Burkina Faso Service Availability and Readiness Assessment (SARA) survey data to provide estimates of essential equipment availability and readiness for malaria care. Predicted values of each indicator were adjusted by the type of health facility, location, and population density. Then, a health district composite readiness profile was built via hierarchical ascendant classification. All surveyed health-facilities were mandated by the Ministry of Health to manage malaria cases. The spatial distribution of essential equipment and malaria readiness was heterogeneous. Around 62.9% of health districts had a high level of readiness to provide malaria care and prevention during pregnancy. Low-performance scores for managing malaria cases were found in big cities. Health districts with low coverage for both first-line antimalarial drugs and rapid diagnostic tests were Baskuy, Bogodogo, Boulmiougou, Nongr-Massoum, Sig-Nonghin, Dafra, and Do. We provide health district estimates and reveal gaps in basic equipment and malaria management resources in some districts that need to be filled. By providing local-scale estimates, this approach could be replicated for other types of indicators to inform decision makers and health program managers and to identify priority areas.
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72
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Bannister-Tyrrell M, Krit M, Sluydts V, Tho S, Sokny M, Mean V, Kim S, Menard D, Grietens KP, Abrams S, Hens N, Coosemans M, Bassat Q, van Hensbroek MB, Durnez L, Van Bortel W. Households or Hotspots? Defining Intervention Targets for Malaria Elimination in Ratanakiri Province, Eastern Cambodia. J Infect Dis 2020; 220:1034-1043. [PMID: 31028393 PMCID: PMC6688056 DOI: 10.1093/infdis/jiz211] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 04/25/2019] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Malaria "hotspots" have been proposed as potential intervention units for targeted malaria elimination. Little is known about hotspot formation and stability in settings outside sub-Saharan Africa. METHODS Clustering of Plasmodium infections at the household and hotspot level was assessed over 2 years in 3 villages in eastern Cambodia. Social and spatial autocorrelation statistics were calculated to assess clustering of malaria risk, and logistic regression was used to assess the effect of living in a malaria hotspot compared to living in a malaria-positive household in the first year of the study on risk of malaria infection in the second year. RESULTS The crude prevalence of Plasmodium infection was 8.4% in 2016 and 3.6% in 2017. Living in a hotspot in 2016 did not predict Plasmodium risk at the individual or household level in 2017 overall, but living in a Plasmodium-positive household in 2016 strongly predicted living in a Plasmodium-positive household in 2017 (Risk Ratio, 5.00 [95% confidence interval, 2.09-11.96], P < .0001). There was no consistent evidence that malaria risk clustered in groups of socially connected individuals from different households. CONCLUSIONS Malaria risk clustered more clearly in households than in hotspots over 2 years. Household-based strategies should be prioritized in malaria elimination programs in this region.
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Affiliation(s)
| | | | - Vincent Sluydts
- Institute of Tropical Medicine, Antwerp.,University of Antwerp, Belgium
| | - Sochantha Tho
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh
| | - Mao Sokny
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh
| | - Vanna Mean
- Ratanakiri Provincial Health Department, Banlung
| | | | | | | | - Steven Abrams
- University of Antwerp, Belgium.,University of Hasselt, Belgium
| | - Niel Hens
- University of Antwerp, Belgium.,University of Hasselt, Belgium
| | | | - Quique Bassat
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique.,Catalan Institution for Research and Advanced Studies, Barcelona, Spain
| | | | - Lies Durnez
- Institute of Tropical Medicine, Antwerp.,University of Antwerp, Belgium
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73
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Ramaswamy A, Mahabala C, Basavaiah SH, Jain A, Chouhan RRS. Asymptomatic malaria carriers and their characterization in hotpops of malaria at Mangalore. Trop Parasitol 2020; 10:24-28. [PMID: 32775288 PMCID: PMC7365503 DOI: 10.4103/tp.tp_71_18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 12/02/2019] [Indexed: 01/11/2023] Open
Abstract
Objective: This study aimed to identify asymptomatic malaria carriers and study the differences in local and migrant population in Mangalore. Materials and Methods: This study was conducted using two-stage cluster sampling. In the first stage, wards were randomly selected. The sample size for each cluster (wards) was determined using the probability proportionate to size method. In the second stage, required number of households was selected using a simple random sampling technique from each cluster. From the selected clusters, samples from 140 participants were collected. Results: Of the 140 cases, 106 (75.7%) were male and 34 (24.3%) were female. Six cases (4.3%) of the 140 cases were positive for malarial parasites, of which gametocytes of Plasmodium falciparum were noted in three cases and schizonts of Plasmodium vivax in three cases. From the total number of cases, 56 (40%) constituted the migrant population and the remaining 84 (60%) were the local population. All the six patients with asymptomatic carriers belonged to the migrant population. Conclusion: A more sound malaria elimination strategy needs to be implemented, for which active surveillance for cases would form a backbone. This study shows that the migrant population seems to show a predilection for asymptomatic malaria, thus targeting malaria elimination programs to areas with a high migrant population would help.
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Affiliation(s)
- Akash Ramaswamy
- Department of Internal Medicine, Kasturba Medical College, Mangalore, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Chakrapani Mahabala
- Department of Internal Medicine, Kasturba Medical College, Mangalore, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Sridevi Hanaganahalli Basavaiah
- Department of Pathology, Kasturba Medical College, Mangalore, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Animesh Jain
- Department of Community Medicine, Kasturba Medical College, Mangalore, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Ravi Raj Singh Chouhan
- Department of District Lead, The India Nutrition Initiatives-Tata Trusts, Barmer, Rajasthan, India
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74
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Golassa L, Cheaveau J, Mohon AN, Pillai DR. Reply to Awandu et al. Clin Infect Dis 2020; 69:1464-1465. [PMID: 30763414 DOI: 10.1093/cid/ciz148] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Affiliation(s)
- Lemu Golassa
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Ethiopia
| | - James Cheaveau
- Department of Microbiology, Immunology, and Infectious Diseases
| | - Abu Naser Mohon
- Department of Microbiology, Immunology, and Infectious Diseases
| | - Dylan R Pillai
- Department of Microbiology, Immunology, and Infectious Diseases.,Department of Pathology and Laboratory Medicine.,Department of Medicine, University of Calgary, Alberta, Canada
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75
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Hsiang MS, Ntuku H, Roberts KW, Dufour MSK, Whittemore B, Tambo M, McCreesh P, Medzihradsky OF, Prach LM, Siloka G, Siame N, Gueye CS, Schrubbe L, Wu L, Scott V, Tessema S, Greenhouse B, Erlank E, Koekemoer LL, Sturrock HJW, Mwilima A, Katokele S, Uusiku P, Bennett A, Smith JL, Kleinschmidt I, Mumbengegwi D, Gosling R. Effectiveness of reactive focal mass drug administration and reactive focal vector control to reduce malaria transmission in the low malaria-endemic setting of Namibia: a cluster-randomised controlled, open-label, two-by-two factorial design trial. Lancet 2020; 395:1361-1373. [PMID: 32334702 PMCID: PMC7184675 DOI: 10.1016/s0140-6736(20)30470-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 01/23/2020] [Accepted: 02/25/2020] [Indexed: 12/23/2022]
Abstract
BACKGROUND In low malaria-endemic settings, screening and treatment of individuals in close proximity to index cases, also known as reactive case detection (RACD), is practised for surveillance and response. However, other approaches could be more effective for reducing transmission. We aimed to evaluate the effectiveness of reactive focal mass drug administration (rfMDA) and reactive focal vector control (RAVC) in the low malaria-endemic setting of Zambezi (Namibia). METHODS We did a cluster-randomised controlled, open-label trial using a two-by-two factorial design of 56 enumeration area clusters in the low malaria-endemic setting of Zambezi (Namibia). We randomly assigned these clusters using restricted randomisation to four groups: RACD only, rfMDA only, RAVC plus RACD, or rfMDA plus RAVC. RACD involved rapid diagnostic testing and treatment with artemether-lumefantrine and single-dose primaquine, rfMDA involved presumptive treatment with artemether-lumefantrine, and RAVC involved indoor residual spraying with pirimiphos-methyl. Interventions were administered within 500 m of index cases. To evaluate the effectiveness of interventions targeting the parasite reservoir in humans (rfMDA vs RACD), in mosquitoes (RAVC vs no RAVC), and in both humans and mosquitoes (rfMDA plus RAVC vs RACD only), an intention-to-treat analysis was done. For each of the three comparisons, the primary outcome was the cumulative incidence of locally acquired malaria cases. This trial is registered with ClinicalTrials.gov, number NCT02610400. FINDINGS Between Jan 1, 2017, and Dec 31, 2017, 55 enumeration area clusters had 1118 eligible index cases that led to 342 interventions covering 8948 individuals. The cumulative incidence of locally acquired malaria was 30·8 per 1000 person-years (95% CI 12·8-48·7) in the clusters that received rfMDA versus 38·3 per 1000 person-years (23·0-53·6) in the clusters that received RACD; 30·2 per 1000 person-years (15·0-45·5) in the clusters that received RAVC versus 38·9 per 1000 person-years (20·7-57·1) in the clusters that did not receive RAVC; and 25·0 per 1000 person-years (5·2-44·7) in the clusters that received rfMDA plus RAVC versus 41·4 per 1000 person-years (21·5-61·2) in the clusters that received RACD only. After adjusting for imbalances in baseline and implementation factors, the incidence of malaria was lower in clusters receiving rfMDA than in those receiving RACD (adjusted incidence rate ratio 0·52 [95% CI 0·16-0·88], p=0·009), lower in clusters receiving RAVC than in those that did not (0·48 [0·16-0·80], p=0·002), and lower in clusters that received rfMDA plus RAVC than in those receiving RACD only (0·26 [0·10-0·68], p=0·006). No serious adverse events were reported. INTERPRETATION In a low malaria-endemic setting, rfMDA and RAVC, implemented alone and in combination, reduced malaria transmission and should be considered as alternatives to RACD for elimination of malaria. FUNDING Novartis Foundation, Bill & Melinda Gates Foundation, and Horchow Family Fund.
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Affiliation(s)
- Michelle S Hsiang
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA; Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, CA, USA; Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA.
| | - Henry Ntuku
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, CA, USA
| | - Kathryn W Roberts
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, CA, USA
| | - Mi-Suk Kang Dufour
- Division of Prevention Science, University of California San Francisco, San Francisco, CA, USA
| | - Brooke Whittemore
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Munyaradzi Tambo
- Multidisciplinary Research Centre, University of Namibia, Windhoek, Namibia
| | - Patrick McCreesh
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA; Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, CA, USA
| | - Oliver F Medzihradsky
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, CA, USA; Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA
| | - Lisa M Prach
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, CA, USA
| | - Griffith Siloka
- Zambezi Ministry of Health and Social Services, Katima, Namibia
| | - Noel Siame
- Zambezi Ministry of Health and Social Services, Katima, Namibia
| | - Cara Smith Gueye
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, CA, USA
| | - Leah Schrubbe
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, CA, USA
| | - Lindsey Wu
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Valerie Scott
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, CA, USA
| | - Sofonias Tessema
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Bryan Greenhouse
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Erica Erlank
- Wits Research Institute for Malaria, South African Medical Research Council Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Lizette L Koekemoer
- Wits Research Institute for Malaria, South African Medical Research Council Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Hugh J W Sturrock
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, CA, USA
| | - Agnes Mwilima
- Zambezi Ministry of Health and Social Services, Katima, Namibia
| | - Stark Katokele
- National Vector-Borne Diseases Control Programme, Namibia Ministry of Health and Social Services, Windhoek, Namibia
| | - Petrina Uusiku
- National Vector-Borne Diseases Control Programme, Namibia Ministry of Health and Social Services, Windhoek, Namibia
| | - Adam Bennett
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, CA, USA
| | - Jennifer L Smith
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, CA, USA
| | - Immo Kleinschmidt
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK; Wits Research Institute for Malaria, South African Medical Research Council Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; Southern African Development Community, Malaria Elimination Eight Secretariat, Windhoek, Namibia
| | - Davis Mumbengegwi
- Multidisciplinary Research Centre, University of Namibia, Windhoek, Namibia
| | - Roly Gosling
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, CA, USA; Multidisciplinary Research Centre, University of Namibia, Windhoek, Namibia
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76
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Survey of asymptomatic malaria and mosquito vectors in Muang Khua District of Phongsaly Province, China-Laos Border. Int J Infect Dis 2020; 96:141-147. [PMID: 32251803 DOI: 10.1016/j.ijid.2020.03.066] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 02/22/2020] [Accepted: 03/25/2020] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVES The China-Laos border has been identified as an important origin of imported malaria outside China. The aim of this study was to describe the asymptomatic malaria infections and epidemic trend of malaria in the China-Laos border region. METHODS A prevalence survey and surveillance of mosquito vectors was conducted in Muang Khua District of Phongsaly Province, China-Laos border, to determine the parasite carriage rate using nested PCR and microscopy. The species composition of malaria vectors was determined by overnight trapping. Blood samples were collected from 354 local residents aged 1-72 years in Sankang village in 2016. A total of 2430 adult mosquitoes were collected from four other villages in Muang Khua District from June to August 2016. RESULTS The parasite carriage rate was 7.63% (27/354) by microscopy or 7.91% (28/354) by nested PCR. The results of surveillance of the mosquito vectors revealed that the predominant genera of adult mosquitoes were Culex (69.92%, 1699/2430) and Anopheles (21.48%, 522/2430). Anopheles sinensis (82.95%, 433/522) was identified as the predominant species among the seven members of Anopheles found in this border region. CONCLUSIONS A high prevalence of asymptomatic malaria was present and the most important malaria vector was Anopheles sinensis, suggesting that the malaria epidemic situation on the China-Laos border is serious.
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77
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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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78
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BULAI IULIAMARTINA, DEPICKÈRE STÉPHANIE, SANCHES VITORHIRATA. INFLUENCE OF ASYMPTOMATIC PEOPLE ON MALARIA TRANSMISSION: A MATHEMATICAL MODEL FOR A LOW-TRANSMISSION AREA CASE. J BIOL SYST 2020. [DOI: 10.1142/s0218339020500072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Malaria remains a primary parasitic disease in the tropical world, generating high morbidity and mortality in human populations. Recently, community surveys showed a high proportion of asymptomatic cases, which are characterized by a low parasitemia and a lack of malaria symptoms. Until now, the asymptomatic population is not treated for malaria and thus remains infective for a long time. In this paper, we introduce a four-dimensional mathematical model to study the influence of asymptomatic people on malaria transmission in low-transmission areas, specifically using data from Brazil. The equilibrium points of the system are calculated, and their stability is analyzed. Via numerical simulations, more in-depth analyzes of the space of some crucial parameters on the asymptomatic population are done, such as the per capita recovery rates of symptomatic and asymptomatic people, the ratio of the density of mosquitoes to that of humans, the mortality rate of mosquitoes and the probability of undergoing asymptomatic infection upon an infectious mosquito bite. Our results indicate that the disease-free equilibrium is inside the stability region if asymptomatic people are treated and/or the ratio of the density of mosquitoes to that of humans is decreased and/or the mortality rate of mosquitoes is increased.
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Affiliation(s)
- IULIA MARTINA BULAI
- Department of Mathematics, Informatics and Economics, University of Basilicata,Potenza, Italy
- Member of the Research Group GNCS of INdAM, Italy
| | - STÉPHANIE DEPICKÈRE
- Instituto de Investigaciones Físicas, Universidad Mayor de San Andrés, La Paz, Bolivia
| | - VITOR HIRATA SANCHES
- Escola de Artes Ciências e Humanidades, Universidade de São Paulo, São Paulo, Brasil
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Abstract
This study aims to ascertain the long-term epidemic trends of malaria and evaluates the probability of achieving the eradication goal by 2020 in China. Data on malaria incidence and deaths were extracted from the China Information System for Disease Control and Prevention. The epidemic trends by sex, age and spatial distribution and predictions of malaria were estimated by using Joinpoint and Poisson regressions. From 1950 to 2016, 227 668 374 malaria cases were reported in China, with an annualised average incidence of 337.02 (336.98–337.07, 95% confidence interval (CI)) per 100 000 population. The incidence decreased with an average annual per cent change (AAPC) of −11.4% (−16.6 to −6.0). There were 36 085 malaria deaths, with an annualised average mortality of 0.534 (0.529–0.540) per 1 000 000 population. The mortality decreased with an AAPC of −8.7% (−13.7 to −3.4). The predicted number of malaria cases and deaths for 2020 is 2 562 and 10, respectively, and zero for indigenous cases. The disease burden of malaria dramatically decreased in China. Though, the goal of malaria elimination is realistic by 2020 in China, routine clinical and entomological surveillance should be continually conducted, especially for the cross-border areas and imported malaria cases.
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80
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Abstract
Malaria is a vector-borne disease that involves multiple parasite species in a variety of ecological settings. However, the parasite species causing the disease, the prevalence of subclinical infections, the emergence of drug resistance, the scale-up of interventions, and the ecological factors affecting malaria transmission, among others, are aspects that vary across areas where malaria is endemic. Such complexities have propelled the study of parasite genetic diversity patterns in the context of epidemiologic investigations. Importantly, molecular studies indicate that the time and spatial distribution of malaria cases reflect epidemiologic processes that cannot be fully understood without characterizing the evolutionary forces shaping parasite population genetic patterns. Although broad in scope, this review in the Microbiology Spectrum Curated Collection: Advances in Molecular Epidemiology highlights the need for understanding population genetic concepts when interpreting parasite molecular data. First, we discuss malaria complexity in terms of the parasite species involved. Second, we describe how molecular data are changing our understanding of malaria incidence and infectiousness. Third, we compare different approaches to generate parasite genetic information in the context of epidemiologically relevant questions related to malaria control. Finally, we describe a few Plasmodium genomic studies as evidence of how these approaches will provide new insights into the malaria disease dynamics. *This article is part of a curated collection.
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81
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Use of real-time multiplex PCR, malaria rapid diagnostic test and microscopy to investigate the prevalence of Plasmodium species among febrile hospital patients in Sierra Leone. Malar J 2020; 19:84. [PMID: 32085711 PMCID: PMC7035765 DOI: 10.1186/s12936-020-03163-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 02/13/2020] [Indexed: 11/24/2022] Open
Abstract
Background Malaria continues to affect over 200 million individuals every year, especially children in Africa. Rapid and sensitive detection and identification of Plasmodium parasites is crucial for treating patients and monitoring of control efforts. Compared to traditional diagnostic methods such as microscopy and rapid diagnostic tests (RDTs), DNA based methods, such as polymerase chain reaction (PCR) offer significantly higher sensitivity, definitive discrimination of Plasmodium species, and detection of mixed infections. While PCR is not currently optimized for routine diagnostics, its role in epidemiological studies is increasing as the world moves closer toward regional and eventually global malaria elimination. This study demonstrates the field use of a novel, ambient temperature-stabilized, multiplexed PCR assay in a small hospital setting in Sierra Leone. Methods Blood samples from 534 febrile individuals reporting to a hospital in Bo, Sierra Leone, were tested using three methods: a commercial RDT, microscopy, and a Multiplex Malaria Sample Ready (MMSR) PCR designed to detect a universal malaria marker and species-specific markers for Plasmodium falciparum and Plasmodium vivax. A separate PCR assay was used to identify species of Plasmodium in samples in which MMSR detected malaria, but was unable to identify the species. Results MMSR detected the presence of any malaria marker in 50.2% of all tested samples with P. falciparum identified in 48.7% of the samples. Plasmodium vivax was not detected. Testing of MMSR P. falciparum-negative/universal malaria-positive specimens with a panel of species-specific PCRs revealed the presence of Plasmodium malariae (n = 2) and Plasmodium ovale (n = 2). The commercial RDT detected P. falciparum in 24.6% of all samples while microscopy was able to detect malaria in 12.8% of tested specimens. Conclusions Wider application of PCR for detection of malaria parasites may help to fill gaps existing as a result of use of microscopy and RDTs. Due to its high sensitivity and specificity, species coverage, room temperature stability and relative low complexity, the MMSR assay may be useful for detection of malaria and epidemiological studies especially in low-resource settings.
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82
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Tao D, McGill B, Hamerly T, Kobayashi T, Khare P, Dziedzic A, Leski T, Holtz A, Shull B, Jedlicka AE, Walzer A, Slowey PD, Slowey CC, Nsango SE, Stenger DA, Chaponda M, Mulenga M, Jacobsen KH, Sullivan DJ, Ryan SJ, Ansumana R, Moss WJ, Morlais I, Dinglasan RR. A saliva-based rapid test to quantify the infectious subclinical malaria parasite reservoir. Sci Transl Med 2020; 11:11/473/eaan4479. [PMID: 30602535 PMCID: PMC6441545 DOI: 10.1126/scitranslmed.aan4479] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Revised: 07/27/2018] [Accepted: 11/30/2018] [Indexed: 01/01/2023]
Abstract
A large proportion of ongoing malaria parasite transmission is attributed to low-density subclinical infections not readily detected by available rapid diagnostic tests (RDTs) or microscopy. Plasmodium falciparum gametocyte carriage is subclinical, but gametocytemic individuals comprise the parasite reservoir that leads to infection of mosquitoes and local transmission. Effective detection and quantification of these carriers can help advance malaria elimination strategies. However, no point-of-need (PON) RDTs for gametocyte detection exist, much less one that can perform noninvasive sampling of saliva outside a clinical setting. Here, we report on the discovery of 35 parasite markers from which we selected a single candidate for use in a PON RDT. We performed a cross-sectional, multi-omics study of saliva from 364 children with subclinical infection in Cameroon and Zambia and produced a prototype saliva-based PON lateral flow immunoassay test for P. falciparum gametocyte carriers. The test is capable of identifying submicroscopic carriage in both clinical and nonclinical settings and is compatible with archived saliva samples.
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Affiliation(s)
- Dingyin Tao
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.,Johns Hopkins Malaria Research Institute, Baltimore, MD 21205, USA
| | - Brent McGill
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.,Johns Hopkins Malaria Research Institute, Baltimore, MD 21205, USA
| | - Timothy Hamerly
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.,Johns Hopkins Malaria Research Institute, Baltimore, MD 21205, USA.,Emerging Pathogens Institute and Department of Infectious Diseases & Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA
| | - Tamaki Kobayashi
- Johns Hopkins Malaria Research Institute, Baltimore, MD 21205, USA.,Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Prachi Khare
- Emerging Pathogens Institute and Department of Infectious Diseases & Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA
| | - Amanda Dziedzic
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Tomasz Leski
- United States Naval Research Laboratory (NRL), Center for Biomolecular Science and Engineering, Washington, DC 20375, USA
| | - Andrew Holtz
- College of Science, George Mason University, Fairfax, VA 22030, USA
| | - Bruce Shull
- Thermo Fisher Scientific, Fremont, CA 94538, USA
| | - Anne E Jedlicka
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | | | | | | | - Sandrine E Nsango
- Laboratoire de Recherche sur le Paludisme, Institut de Recherche pour le Développement-Organisation de Coordination et de Coopération pour la Lutte Contre les Grandes Endémies en Afrique Centrale (IRD-OCEAC), Yaoundé, Cameroon.,Faculty of Medicine and Pharmaceutical Sciences, University of Douala, PO Box 2701, Douala, Cameroon
| | - David A Stenger
- United States Naval Research Laboratory (NRL), Center for Biomolecular Science and Engineering, Washington, DC 20375, USA
| | | | | | - Kathryn H Jacobsen
- College of Health and Human Services, George Mason University, Fairfax, VA 22030, USA
| | - David J Sullivan
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Sadie J Ryan
- Emerging Pathogens Institute and Department of Geography, College of Liberal Arts and Sciences, University of Florida, Gainesville, FL 32611, USA
| | - Rashid Ansumana
- Mercy Hospital Research Laboratory, Kulanda Town, Bo, Sierra Leone
| | - William J Moss
- Johns Hopkins Malaria Research Institute, Baltimore, MD 21205, USA.,Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Isabelle Morlais
- Laboratoire de Recherche sur le Paludisme, Institut de Recherche pour le Développement-Organisation de Coordination et de Coopération pour la Lutte Contre les Grandes Endémies en Afrique Centrale (IRD-OCEAC), Yaoundé, Cameroon
| | - Rhoel R Dinglasan
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA. .,Johns Hopkins Malaria Research Institute, Baltimore, MD 21205, USA.,Emerging Pathogens Institute and Department of Infectious Diseases & Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA
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Rosas-Aguirre A, Patra KP, Calderón M, Torres K, Gamboa D, Arocutipa E, Málaga E, Garro K, Fernández C, Trompeter G, Alnasser Y, Llanos-Cuentas A, Gilman RH, Vinetz JM. Anti-MSP-10 IgG indicates recent exposure to Plasmodium vivax infection in the Peruvian Amazon. JCI Insight 2020; 5:130769. [PMID: 31770108 DOI: 10.1172/jci.insight.130769] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 11/25/2019] [Indexed: 11/17/2022] Open
Abstract
BACKGROUNDSerological tools for the accurate detection of recent malaria exposure are needed to guide and monitor malaria control efforts. IgG responses against Plasmodium vivax and P. falciparum merozoite surface protein-10 (MSP10) were measured as a potential way to identify recent malaria exposure in the Peruvian Amazon.METHODSA field-based study included 470 participants in a longitudinal cohort who completed a comprehensive evaluation: light microscopy and PCR on enrollment, at least 1 monthly follow-up by light microscopy, a second PCR, and serum and dried blood spots for serological analysis at the end of the follow-up. IgG titers against novel mammalian cell-produced recombinant PvMSP10 and PfMSP10 were determined by ELISA.RESULTSDuring the follow-up period, 205 participants were infected, including 171 with P. vivax, 26 with P. falciparum, 6 with infections by both species but at different times, and 2 with mixed infections. Exposure to P. vivax was more accurately identified when serological responses to PvMSP10 were obtained from serum (sensitivity, 58.1%; specificity, 81.8%; AUC: 0.76) than from dried blood spots (sensitivity, 35.2; specificity, 83.5%; AUC: 0.64) (PAUC < 0.001). Sensitivity was highest (serum, 82.9%; dried blood spot, 45.7%) with confirmed P. vivax infections occurring 7-30 days before sample collection; sensitivity decreased significantly in relation to time since last documented infection. PvMSP10 serological data did not show evidence of interspecies cross-reactivity. Anti-PfMSP10 responses poorly discriminated between P. falciparum-exposed and nonexposed individuals (AUC = 0.59; P > 0.05).CONCLUSIONAnti-PvMSP10 IgG indicates recent exposure to P. vivax at the population level in the Amazon region. Serum, not dried blood spots, should be used for such serological tests.FUNDINGCooperative agreement U19AI089681 from the United States Public Health Service, NIH/National Institute of Allergy and Infectious Diseases, as the Amazonian International Center of Excellence in Malaria Research.
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Affiliation(s)
- Angel Rosas-Aguirre
- Fund for Scientific Research FNRS, Brussels, Belgium.,Research Institute of Health and Society, Université catholique de Louvain, Brussels, Belgium.,Instituto de Medicina, Tropical "Alexander von Humboldt," Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Kailash P Patra
- Division of Infectious Diseases, Department of Medicine, University of California San Diego School of Medicine, La Jolla, California, USA
| | - Maritza Calderón
- Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofia, and
| | - Katherine Torres
- Instituto de Medicina, Tropical "Alexander von Humboldt," Universidad Peruana Cayetano Heredia, Lima, Peru.,Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Dionicia Gamboa
- Instituto de Medicina, Tropical "Alexander von Humboldt," Universidad Peruana Cayetano Heredia, Lima, Peru.,Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofia, and.,Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Edith Arocutipa
- Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofia, and.,Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Edith Málaga
- Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofia, and.,Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Katherine Garro
- Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Carlos Fernández
- Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Grace Trompeter
- Program in Global Disease Epidemiology and Control, Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
| | - Yossef Alnasser
- Program in Global Disease Epidemiology and Control, Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
| | - Alejandro Llanos-Cuentas
- Instituto de Medicina, Tropical "Alexander von Humboldt," Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Robert H Gilman
- Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofia, and.,Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru.,Program in Global Disease Epidemiology and Control, Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
| | - Joseph M Vinetz
- Division of Infectious Diseases, Department of Medicine, University of California San Diego School of Medicine, La Jolla, California, USA.,Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofia, and.,Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
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84
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Udoh BE, Iwalokun BA, Etukumana E, Amoo J. Asymptomatic falciparum Malaria and its Effects on Type 2 Diabetes Mellitus Patients in Lagos, Nigeria. SAUDI JOURNAL OF MEDICINE & MEDICAL SCIENCES 2019; 8:32-40. [PMID: 31929776 PMCID: PMC6945314 DOI: 10.4103/sjmms.sjmms_178_18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 12/25/2018] [Accepted: 05/16/2019] [Indexed: 11/04/2022]
Abstract
Background Asymptomatic malaria (ASM) constitutes a reservoir of malaria parasites that sustain transmission and threaten elimination efforts. Studies have also shown a significant relation between insulin resistance and malaria infection. However, data on the clinical effects of ASM and its patterns of carriage among adult malaria patients is limited. Objectives To determine the prevalence of ASM due to Plasmodium falciparum among adult type 2 diabetes (T2DM) patients in Lagos, Nigeria; to assess the diagnostic performance of light microscopy and histidine-rich protein 2 rapid diagnostic test (HRP-2 RDT); and to determine the effects of ASM on glycemic control and anemia. Materials and Methods This cross-sectional study enrolled 208 afebrile, nonobese, nonhypertensive T2DM patients, aged 40-70 years, undergoing treatment (adherence, ≥95%) at six private health facilities in Lagos, Nigeria, between March and August 2015. Sociodemographic data were obtained using a semi-structured questionnaire and clinical case files. Venous blood samples were collected and processed for fasting blood sugar estimation, packed cell volume determination and malaria parasite detection by HRP2-RDT, light microscopy and polymerase chain reaction (PCR). Results The mean age of the patients was 54.5 years. ASM was diagnosed in 16.8%, 7.2% and 4.3% of the patients by PCR, light microscopy and HRP2-RDT, respectively. ASM was significantly (P < 0.05) associated with poor glycemic control, anemia and insulin resistance. The overall parasitemia ranged from 85 to 3789 parasites/μL (median, 1580 parasites/μL). Benchmarking against the PCR results, light microscopy and rapid diagnostic tests were found to have a sensitivity (95% confidence interval) of 42.9% (26.5-59.3) and 22.9% (12.1-39), respectively, in diagnosing ASM. Conclusion This study revealed that T2DM patients in Lagos, Nigeria, are potential reservoirs of asymptomatic Plasmodium falciparum, which has a significantly negative effect on glycemic control and anemia. The study also found PCR to be the most effective diagnostic method.
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Affiliation(s)
- Bernice Enobong Udoh
- Department of Medical Microbiology and Parasitology, Olabisi Onabanjo University, Sagamu, Ogun State, Nigeria
| | - Bamidele Abiodun Iwalokun
- Department of Medical Microbiology and Parasitology, Olabisi Onabanjo University, Sagamu, Ogun State, Nigeria.,Department of Molecular Biology and Biotechnology, Nigerian Institute of Medical Research, Lagos, Nigeria
| | - Etiobong Etukumana
- Department of Family Medicine, University of Uyo Teaching Hospital, Akwa Ibom, Nigeria
| | - Joseph Amoo
- Department of Medical Microbiology and Parasitology, Olabisi Onabanjo University, Sagamu, Ogun State, Nigeria
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85
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Canavati SE, Kelly GC, Quintero CE, Vo TH, Tran LK, Ohrt C, Ngo TD, Tran DT, Martin NJ. Risk factor assessment for clinical malaria among forest-goers in a pre-elimination setting in Phu Yen Province, Vietnam. Malar J 2019; 18:435. [PMID: 31861988 PMCID: PMC6923829 DOI: 10.1186/s12936-019-3068-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Accepted: 12/09/2019] [Indexed: 11/13/2022] Open
Abstract
Background The transition from malaria control to elimination requires understanding and targeting interventions among high-risk populations. In Vietnam, forest-goers are often difficult to test, treat and follow-up for malaria because they are highly mobile. If undiagnosed, forest-goers can maintain parasite reservoirs and contribute to ongoing malaria transmission. Methods A case–control study was conducted to identify malaria risk factors associated with forest-goers in three communes in Phu Yen Province, Vietnam. Cases (n = 81) were residents from the study area diagnosed with malaria and known to frequent forest areas. Controls (n = 94) were randomly selected forest-going residents from within the study area with no identified malaria infection. Participants were interviewed face-to-face using a standard questionnaire to identify malaria risk factors. Logistic regression was used to calculate odds ratios (ORs) and 95% CI for risk factors after adjusting for socio-demographic characteristics. Results Among the cases, malaria infection varied by species: 66.7% were positive for Plasmodium falciparum, 29.6% for Plasmodium vivax, and 3.7% were diagnosed as mixed infection. Cases were less likely than controls to use treated nets (aOR = 0.31; 95% CI 0.12–0.80), work after dark (aOR = 2.93; 95% CI 1.35, 6.34), bath in a stream after dark (aOR = 2.44; 95% CI 1.02–5.88), and collect water after dark (aOR = 1.99; 95% CI 1.02–3.90). Conclusions As Vietnam moves toward malaria elimination, these findings can inform behaviour change communication and malaria prevention strategies, incorporating the risk of after-dark and water-related activities, in this priority and difficult-to-access population group.
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Affiliation(s)
- Sara E Canavati
- Vysnova Partners, Inc., 4915 St. Elmo Ave., Bethesda, 20814, USA
| | - Gerard C Kelly
- Vysnova Partners, Inc., 4915 St. Elmo Ave., Bethesda, 20814, USA
| | - Cesia E Quintero
- Vysnova Partners, Inc., 4915 St. Elmo Ave., Bethesda, 20814, USA
| | - Thuan Huu Vo
- Vysnova Partners, Inc., 4915 St. Elmo Ave., Bethesda, 20814, USA
| | - Long Khanh Tran
- Vysnova Partners, Inc., 4915 St. Elmo Ave., Bethesda, 20814, USA
| | - Colin Ohrt
- Vysnova Partners, Inc., 4915 St. Elmo Ave., Bethesda, 20814, USA
| | - Thang Duc Ngo
- National Institute of Malariology, Parasitology and Entomology, 35 Trung Van, Hanoi, Vietnam
| | - Duong Thanh Tran
- National Institute of Malariology, Parasitology and Entomology, 35 Trung Van, Hanoi, Vietnam
| | - Nicholas J Martin
- Naval Medical Research Unit TWO, PSA Sembawang Deptford Rd., Building 7-4, Singapore, 759657, Singapore.
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86
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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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87
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Nelson CS, Sumner KM, Freedman E, Saelens JW, Obala AA, Mangeni JN, Taylor SM, O'Meara WP. High-resolution micro-epidemiology of parasite spatial and temporal dynamics in a high malaria transmission setting in Kenya. Nat Commun 2019; 10:5615. [PMID: 31819062 PMCID: PMC6901486 DOI: 10.1038/s41467-019-13578-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 11/14/2019] [Indexed: 01/03/2023] Open
Abstract
Novel interventions that leverage the heterogeneity of parasite transmission are needed to achieve malaria elimination. To better understand spatial and temporal dynamics of transmission, we applied amplicon next-generation sequencing of two polymorphic gene regions (csp and ama1) to a cohort identified via reactive case detection in a high-transmission setting in western Kenya. From April 2013 to July 2014, we enrolled 442 symptomatic children with malaria, 442 matched controls, and all household members of both groups. Here, we evaluate genetic similarity between infected individuals using three indices: sharing of parasite haplotypes on binary and proportional scales and the L1 norm. Symptomatic children more commonly share haplotypes with their own household members. Furthermore, we observe robust temporal structuring of parasite genetic similarity and identify the unique molecular signature of an outbreak. These findings of both micro- and macro-scale organization of parasite populations might be harnessed to inform next-generation malaria control measures. Here, Nelson et al. use amplicon next-generation sequencing of two P. falciparum polymorphic gene regions to investigate the genetic similarity of parasite populations across time and space in a pediatric cohort in Kenya. They identify both micro- and macro-scale structuring of malaria parasites in this high-transmission setting, which could inform future intervention strategies.
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Affiliation(s)
- Cody S Nelson
- Duke Global Health Institute, Duke University, Durham, North Carolina, USA.
| | - Kelsey M Sumner
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA.,Division of Infectious Diseases, Duke University School of Medicine, Durham, North Carolina, USA
| | - Elizabeth Freedman
- Division of Infectious Diseases, Duke University School of Medicine, Durham, North Carolina, USA
| | - Joseph W Saelens
- Division of Infectious Diseases, Duke University School of Medicine, Durham, North Carolina, USA
| | - Andrew A Obala
- School of Medicine, Moi University College of Health Sciences, Eldoret, Kenya
| | - Judith N Mangeni
- School of Nursing, Moi University College of Health Sciences, Eldoret, Kenya
| | - Steve M Taylor
- Duke Global Health Institute, Duke University, Durham, North Carolina, USA.,Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA.,Division of Infectious Diseases, Duke University School of Medicine, Durham, North Carolina, USA
| | - Wendy P O'Meara
- Duke Global Health Institute, Duke University, Durham, North Carolina, USA.,Division of Infectious Diseases, Duke University School of Medicine, Durham, North Carolina, USA
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88
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Cheaveau J, Mogollon DC, Mohon MAN, Golassa L, Yewhalaw D, Pillai DR. Asymptomatic malaria in the clinical and public health context. Expert Rev Anti Infect Ther 2019; 17:997-1010. [PMID: 31718324 DOI: 10.1080/14787210.2019.1693259] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Introduction: Historically, the global community has focused on the control of symptomatic malaria. However, interest in asymptomatic malaria has been growing, particularly in the context of malaria elimination.Areas covered: We undertook a comprehensive PubMed literature review on asymptomatic malaria as it relates to detection and elimination with emphasis between 2014 and 2019. Diagnostic tools with a low limit of detection (LOD) have allowed us to develop a more detailed understanding of asymptomatic malaria and its impact. These highly sensitive diagnostics have demonstrated that the prevalence of asymptomatic malaria is greater than previously thought. In addition, it is now possible to detect the malaria reservoir in the community, something that was previously not feasible. Asymptomatic malaria has previously not been treated, but research has begun to examine whether treating individuals with asymptomatic malaria may lead to health benefits. Finally, we have begun to understand the importance of asymptomatic malaria in ongoing transmission.Expert opinion: Therefore, with malaria elimination back on the agenda, asymptomatic malaria can no longer be ignored, especially in light of new ultra-sensitive diagnostic tools.
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Affiliation(s)
- James Cheaveau
- Department of Microbiology, Immunology, and Infectious Diseases, University of Calgary, Canada, AB, Canada
| | - Daniel Castaneda Mogollon
- Department of Microbiology, Immunology, and Infectious Diseases, University of Calgary, Canada, AB, Canada
| | - Md Abu Naser Mohon
- Department of Microbiology, Immunology, and Infectious Diseases, University of Calgary, Canada, AB, Canada
| | - Lemu Golassa
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Delenasaw Yewhalaw
- Department of Medical Laboratory Sciences and Pathology, College of Health Sciences, Jimma University, Jimma, Ethiopia
| | - Dylan R Pillai
- Department of Microbiology, Immunology, and Infectious Diseases, University of Calgary, Canada, AB, Canada.,Department of Medicine, University of Calgary, Calgary, AB, Canada.,Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, AB, Canada
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89
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Brunner NC, Chacky F, Mandike R, Mohamed A, Runge M, Thawer SG, Ross A, Vounatsou P, Lengeler C, Molteni F, Hetzel MW. The potential of pregnant women as a sentinel population for malaria surveillance. Malar J 2019; 18:370. [PMID: 31752889 PMCID: PMC6873723 DOI: 10.1186/s12936-019-2999-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 11/11/2019] [Indexed: 12/21/2022] Open
Abstract
Background With increasing spatial heterogeneity of malaria transmission and a shift of the disease burden towards older children and adults, pregnant women attending antenatal care (ANC) have been proposed as a pragmatic sentinel population for malaria surveillance. However, the representativeness of routine ANC malaria test-positivity and its relationship with prevalence in other population subgroups are yet to be investigated. Methods Monthly ANC malaria test-positivity data from all Tanzanian health facilities for January 2014 to May 2016 was compared to prevalence data from the School Malaria Parasitaemia Survey 2015, the Malaria Indicator Survey (MIS) 2015/16, the Malaria Atlas Project 2015, and a Bayesian model fitted to MIS data. Linear regression was used to describe the difference between malaria test-positivity in pregnant women and respective comparison groups as a function of ANC test-positivity and potential covariates. Results The relationship between ANC test-positivity and survey prevalence in children follows spatially and biologically meaningful patterns. However, the uncertainty of the relationship was substantial, particularly in areas with high or perennial transmission. In comparison, modelled data estimated higher prevalence in children at low transmission intensities and lower prevalence at higher transmission intensities. Conclusions Pregnant women attending ANC are a pragmatic sentinel population to assess heterogeneity and trends in malaria prevalence in Tanzania. Yet, since ANC malaria test-positivity cannot be used to directly predict the prevalence in other population subgroups, complementary community-level measurements remain highly relevant.
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Affiliation(s)
- Nina C Brunner
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002, Basel, Switzerland.,University of Basel, Petersplatz 1, 4003, Basel, Switzerland
| | - Frank Chacky
- National Malaria Control Programme, P.O. Box 9083, Dar es Salaam, United Republic of Tanzania.,Ministry of Health, Community Development, Gender, Elderly and Children, Building No. 11, P. O. Box 743, 40478, Dodoma, United Republic of Tanzania
| | - Renata Mandike
- National Malaria Control Programme, P.O. Box 9083, Dar es Salaam, United Republic of Tanzania.,Ministry of Health, Community Development, Gender, Elderly and Children, Building No. 11, P. O. Box 743, 40478, Dodoma, United Republic of Tanzania
| | - Ally Mohamed
- National Malaria Control Programme, P.O. Box 9083, Dar es Salaam, United Republic of Tanzania.,Ministry of Health, Community Development, Gender, Elderly and Children, Building No. 11, P. O. Box 743, 40478, Dodoma, United Republic of Tanzania
| | - Manuela Runge
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002, Basel, Switzerland.,University of Basel, Petersplatz 1, 4003, Basel, Switzerland
| | - Sumaiyya G Thawer
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002, Basel, Switzerland.,University of Basel, Petersplatz 1, 4003, Basel, Switzerland.,National Malaria Control Programme, P.O. Box 9083, Dar es Salaam, United Republic of Tanzania
| | - Amanda Ross
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002, Basel, Switzerland.,University of Basel, Petersplatz 1, 4003, Basel, Switzerland
| | - Penelope Vounatsou
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002, Basel, Switzerland.,University of Basel, Petersplatz 1, 4003, Basel, Switzerland
| | - Christian Lengeler
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002, Basel, Switzerland.,University of Basel, Petersplatz 1, 4003, Basel, Switzerland
| | - Fabrizio Molteni
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002, Basel, Switzerland.,University of Basel, Petersplatz 1, 4003, Basel, Switzerland.,National Malaria Control Programme, P.O. Box 9083, Dar es Salaam, United Republic of Tanzania
| | - Manuel W Hetzel
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002, Basel, Switzerland. .,University of Basel, Petersplatz 1, 4003, Basel, Switzerland.
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90
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Heraud P, Chatchawal P, Wongwattanakul M, Tippayawat P, Doerig C, Jearanaikoon P, Perez-Guaita D, Wood BR. Infrared spectroscopy coupled to cloud-based data management as a tool to diagnose malaria: a pilot study in a malaria-endemic country. Malar J 2019; 18:348. [PMID: 31619246 PMCID: PMC6794904 DOI: 10.1186/s12936-019-2945-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 09/03/2019] [Indexed: 01/20/2023] Open
Abstract
Background Widespread elimination of malaria requires an ultra-sensitive detection method that can detect low parasitaemia levels seen in asymptomatic carriers who act as reservoirs for further transmission of the disease, but is inexpensive and easy to deploy in the field in low income settings. It was hypothesized that a new method of malaria detection based on infrared spectroscopy, shown in the laboratory to have similar sensitivity to PCR based detection, could prove effective in detecting malaria in a field setting using cheap portable units with data management systems allowing them to be used by users inexpert in spectroscopy. This study was designed to determine whether the methodology developed in the laboratory could be translated to the field to diagnose the presence of Plasmodium in the blood of patients presenting at hospital with symptoms of malaria, as a precursor to trials testing the sensitivity of to detect asymptomatic carriers. Methods The field study tested 318 patients presenting with suspected malaria at four regional clinics in Thailand. Two portable infrared spectrometers were employed, operated from a laptop computer or a mobile telephone with in-built software that guided the user through the simple measurement steps. Diagnostic modelling and validation testing using linear and machine learning approaches was performed against the gold standard qPCR. Sample spectra from 318 patients were used for building calibration models (112 positive and 110 negative samples according to PCR testing) and independent validation testing (39 positive and 57 negatives samples by PCR). Results The machine learning classification (support vector machines; SVM) performed with 92% sensitivity (3 false negatives) and 97% specificity (2 false positives). The Area Under the Receiver Operation Curve (AUROC) for the SVM classification was 0.98. These results may be better than as stated as one of the spectroscopy false positives was infected by a Plasmodium species other than Plasmodium falciparum or Plasmodium vivax, not detected by the PCR primers employed. Conclusions In conclusion, it was demonstrated that ATR-FTIR spectroscopy could be used as an efficient and reliable malaria diagnostic tool and has the potential to be developed for use at point of care under tropical field conditions with spectra able to be analysed via a Cloud-based system, and the diagnostic results returned to the user’s mobile telephone or computer. The combination of accessibility to mass screening, high sensitivity and selectivity, low logistics requirements and portability, makes this new approach a potentially outstanding tool in the context of malaria elimination programmes. The next step in the experimental programme now underway is to reduce the sample requirements to fingerprick volumes.
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Affiliation(s)
- Philip Heraud
- Centre for Biospectroscopy, School of Chemistry, Faculty of Science, Monash University, Wellington Road, Clayton, VIC, 3800, Australia.,Department of Microbiology and the Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Wellington Road, Clayton, VIC, 3800, Australia
| | - Patutong Chatchawal
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Molin Wongwattanakul
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand.,Graduate School, Khon Kaen University, Khon Kaen, Thailand
| | - Patcharaporn Tippayawat
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Christian Doerig
- Department of Microbiology and the Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Wellington Road, Clayton, VIC, 3800, Australia
| | - Patcharee Jearanaikoon
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - David Perez-Guaita
- Centre for Biospectroscopy, School of Chemistry, Faculty of Science, Monash University, Wellington Road, Clayton, VIC, 3800, Australia.
| | - Bayden R Wood
- Centre for Biospectroscopy, School of Chemistry, Faculty of Science, Monash University, Wellington Road, Clayton, VIC, 3800, Australia.
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91
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Kimenyi KM, Wamae K, Ochola-Oyier LI. Understanding P. falciparum Asymptomatic Infections: A Proposition for a Transcriptomic Approach. Front Immunol 2019; 10:2398. [PMID: 31681289 PMCID: PMC6803459 DOI: 10.3389/fimmu.2019.02398] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 09/25/2019] [Indexed: 12/11/2022] Open
Abstract
Malaria is still a significant public health burden in the tropics. Infection with malaria causing parasites results in a wide range of clinical disease presentations, from severe to uncomplicated or mild, and in the poorly understood asymptomatic infections. The complexity of asymptomatic infections is due to the intricate interplay between factors derived from the human host, parasite, and environment. Asymptomatic infections often go undetected and provide a silent natural reservoir that sustains malaria transmission. This creates a major obstacle for malaria control and elimination efforts. Numerous studies have tried to characterize asymptomatic infections, unanimously revealing that host immunity is the underlying factor in the maintenance of these infections and in the risk of developing febrile malaria infections. An in-depth understanding of how host immunity and parasite factors interact to cause malaria disease tolerance is thus required. This review primarily focuses on understanding anti-inflammatory and pro-inflammatory responses to asymptomatic infections in malaria endemic areas, to present the view that it is potentially the shift in host immunity toward an anti-inflammatory profile that maintains asymptomatic infections after multiple exposures to malaria. Conversely, symptomatic infections are skewed toward a pro-inflammatory immune profile. Moreover, we propose that these infections can be better interrogated using next generation sequencing technologies, in particular RNA sequencing (RNA-seq), to investigate the immune system using the transcriptome sampled during a clearly defined asymptomatic infection.
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Affiliation(s)
- Kelvin M Kimenyi
- KEMRI-Wellcome Trust Research Programme, CGMRC, Kilifi, Kenya.,Centre for Biotechnology and Bioinformatics, University of Nairobi, Nairobi, Kenya
| | - Kevin Wamae
- KEMRI-Wellcome Trust Research Programme, CGMRC, Kilifi, Kenya
| | - Lynette Isabella Ochola-Oyier
- KEMRI-Wellcome Trust Research Programme, CGMRC, Kilifi, Kenya.,Pwani University Bioscience Research Centre, Pwani University, Kilifi, Kenya
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92
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Rossi G, Vernaeve L, Van den Bergh R, Nguon C, Debackere M, Abello Peiri C, Van V, Khim N, Kim S, Eam R, Ken M, Khean C, De Smet M, Menard D, Kindermans JM. Closing in on the Reservoir: Proactive Case Detection in High-Risk Groups as a Strategy to Detect Plasmodium falciparum Asymptomatic Carriers in Cambodia. Clin Infect Dis 2019; 66:1610-1617. [PMID: 29361021 DOI: 10.1093/cid/cix1064] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 12/19/2017] [Indexed: 12/11/2022] Open
Abstract
Background In the frame of elimination strategies of Plasmodium falciparum (Pf), active case detection has been recommended as complementary approach to the existing passive case detection programs. We trialed a polymerase chain reaction (PCR)-based active detection strategy targeting asymptomatic individuals, named proactive case detection (PACD), with the aim of assessing its feasibility, the extra yield of Pf infections, and the at-risk population for Pf carriage status. Methods A pilot of PACD was conducted in 3 villages in Chey Saen district (Preah Vihear province, Cambodia), from December 2015 to March 2016. Voluntary screening and treatment, following health promotion sensitization, was used as mobilization strategy. Results A total of 2802 persons were tested, representing 54% of the population. PACD (n = 30) and the respective reactive case detection (RACD) (n = 3) identified 33 Pf carriers, approximately twice as many as the Pf infections (n = 17) diagnosed in passive case detection and respective RACD, by health centers and village malaria workers using PCR, in the same villages/period. Final positivity rate was 1.07% (30/2802). People spending nighttime in forests and plantations were found to be at increased risk for Pf infection (odds ratio [OR], 3.4 [95% CI, 1.6-7.2], P = .002 and OR, 2.3 [95% CI, 1.1-4.9], P = .03, respectively). Conclusions We demonstrated the usefulness of the PACD component in identifying Pf asymptomatic carriers. Social mobilization and promotion led to good attendance of specific risk groups, identified to be, in the Cambodian context, individuals spending nighttime in forest and plantations.
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Affiliation(s)
| | | | | | - Chea Nguon
- Centre for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | | | | | - Vuthea Van
- Médecins Sans Frontières, Phnom Penh, Cambodia
| | - Nimol Khim
- Malaria Molecular Epidemiology Unit, Institut Pasteur, Phnom Penh, Cambodia
| | - Saorin Kim
- Malaria Molecular Epidemiology Unit, Institut Pasteur, Phnom Penh, Cambodia
| | - Rotha Eam
- Malaria Molecular Epidemiology Unit, Institut Pasteur, Phnom Penh, Cambodia
| | - Malen Ken
- Malaria Molecular Epidemiology Unit, Institut Pasteur, Phnom Penh, Cambodia
| | - Chanra Khean
- Malaria Molecular Epidemiology Unit, Institut Pasteur, Phnom Penh, Cambodia
| | - Martin De Smet
- Médecins Sans Frontières Operational Center, Brussels, Belgium
| | - Didier Menard
- Malaria Molecular Epidemiology Unit, Institut Pasteur, Phnom Penh, Cambodia.,Unité Biologie des Interactions Hôte-Parasite, Institut Pasteur, Paris, France
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93
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Arji G, Ahmadi H, Nilashi M, A Rashid T, Hassan Ahmed O, Aljojo N, Zainol A. Fuzzy logic approach for infectious disease diagnosis: A methodical evaluation, literature and classification. Biocybern Biomed Eng 2019; 39:937-955. [PMID: 32287711 PMCID: PMC7115764 DOI: 10.1016/j.bbe.2019.09.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 09/15/2019] [Accepted: 09/17/2019] [Indexed: 01/04/2023]
Abstract
This paper presents a systematic review of the literature and the classification of fuzzy logic application in an infectious disease. Although the emergence of infectious diseases and their subsequent spread have a significant impact on global health and economics, a comprehensive literature evaluation of this topic has yet to be carried out. Thus, the current study encompasses the first systematic, identifiable and comprehensive academic literature evaluation and classification of the fuzzy logic methods in infectious diseases. 40 papers on this topic, which have been published from 2005 to 2019 and related to the human infectious diseases were evaluated and analyzed. The findings of this evaluation clearly show that the fuzzy logic methods are vastly used for diagnosis of diseases such as dengue fever, hepatitis and tuberculosis. The key fuzzy logic methods used for the infectious disease are the fuzzy inference system; the rule-based fuzzy logic, Adaptive Neuro-Fuzzy Inference System (ANFIS) and fuzzy cognitive map. Furthermore, the accuracy, sensitivity, specificity and the Receiver Operating Characteristic (ROC) curve were universally applied for a performance evaluation of the fuzzy logic techniques. This thesis will also address the various needs between the different industries, practitioners and researchers to encourage more research regarding the more overlooked areas, and it will conclude with several suggestions for the future infectious disease researches.
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Affiliation(s)
- Goli Arji
- School of Nursing and Midwifery, Health Information Technology Department, Saveh University of Medical Sciences, Iran
| | - Hossein Ahmadi
- Halal Research Center of IRI, FDA, Tehran, Iran
- Department of Information Technology, University of Human Development, Sulaymaniyah, Iraq
| | - Mehrbakhsh Nilashi
- Department for Management of Science and Technology Development, Ton Duc Thang University, Ho Chi Minh City, Vietnam
- Faculty of Information Technology, Ton Duc Thang University, Ho Chi Minh City, Vietnam
| | - Tarik A Rashid
- Computer Science and Engineering Department, University of Kurdistan Hewler, Erbil, Kurdistan, Iraq
| | - Omed Hassan Ahmed
- School of Computing and Engineering, University of Huddersfield, Queensgate, Huddersfield, United Kingdom
- University of Human Development, College of Science and Technology, Department of Information Technology, Sulaymaniyah, Iraq
| | - Nahla Aljojo
- College of Computer Science and Engineering, Department of Information Systems and Technology, University of Jeddah, Jeddah, Saudi Arabia
| | - Azida Zainol
- Department of Software Engineering, College of Computer Science and Engineering, University of Jeddah, Jeddah, Saudi Arabia
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94
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Rossi G, Van den Bergh R, Nguon C, Debackere M, Vernaeve L, Khim N, Kim S, Menard D, De Smet M, Kindermans JM. Adapting Reactive Case Detection Strategies for falciparum Malaria in a Low-Transmission Area in Cambodia. Clin Infect Dis 2019; 66:296-298. [PMID: 29020325 DOI: 10.1093/cid/cix781] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 08/26/2017] [Indexed: 12/26/2022] Open
Abstract
Reactive case detection around falciparum malaria cases in Cambodia presents a low output. We improved it by including individuals occupationally coexposed with index case patients and using polymerase chain reaction-based diagnosis. The positivity rate increased from 0.16% to 3.9%.
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Affiliation(s)
| | | | - Chea Nguon
- Centre for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | | | | | | | | | | | - Martin De Smet
- Médecins Sans Frontières Operational Center Brussels, Belgium
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95
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Wangchuk S, Gyeltshen S, Dorji K, Wangdi T, Dukpa T, Namgay R, Dorjee S, Tobgay T, Chaijaroenkul W, Na-Bangchang K. Malaria elimination in Bhutan: asymptomatic malaria cases in the Bhutanese population living in malaria-risk areas and in migrant workers from India. Rev Inst Med Trop Sao Paulo 2019; 61:e52. [PMID: 31531630 PMCID: PMC6746194 DOI: 10.1590/s1678-9946201961052] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 07/31/2019] [Indexed: 11/28/2022] Open
Abstract
In 2018, Bhutan reported 54 cases of malaria, of which six were indigenous, 14 introduced and 34 imported. Considering the continuous reduction in the number of indigenous cases, Bhutan plans to eliminate malaria by 2025 under the Bhutan Malaria Elimination Strategy. The study was conducted to assess the presence of asymptomatic plasmodial infection in both, Bhutanese population living in malaria-risk areas and in migrant workers to guide the elimination strategies. A cross-sectional study was conducted from April to May 2016 in 750 Bhutanese people and 473 migrant workers. Plasmodium falciparum and Plasmodium vivax infections were investigated by using a rapid diagnostic test (RDT) and the polymerase chain reaction (PCR). Prevalence of asymptomatic plasmodial infection based on PCR was 0.27% (95% CI: 0.05–1.07%) among Bhutanese people with a mean age of 43 years old. The proportions of males and females were 45% and 55%, respectively. Among migrant workers, the prevalence of asymptomatic plasmodial infection was 0.42% (95% CI: 0.07–1.69%) with a mean age of 30 years old. The majority of migrant workers were from the neighboring Indian State of West Bengal (57.51%), followed by Assam (12.26%). RDT in both study groups did not detect any plasmodial infection. The presence of a low prevalence of asymptomatic plasmodial infection indicates that the current elimination strategies and interventions are effective.
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Affiliation(s)
- Sonam Wangchuk
- Bhutan Ministry of Health, Royal Center for Disease Control, Thimphu, Bhutan
| | - Sonam Gyeltshen
- Bhutan Ministry of Health, Royal Center for Disease Control, Thimphu, Bhutan
| | - Kunzang Dorji
- Bhutan Ministry of Health, Royal Center for Disease Control, Thimphu, Bhutan
| | - Tenzin Wangdi
- Bhutan Ministry of Health, Department of Public Health, Vector Borne Disease Control Programme, Thimphu, Bhutan
| | - Tobgyel Dukpa
- Bhutan Ministry of Health, Department of Public Health, Vector Borne Disease Control Programme, Thimphu, Bhutan
| | - Rinzin Namgay
- Bhutan Ministry of Health, Department of Public Health, Vector Borne Disease Control Programme, Thimphu, Bhutan
| | - Sithar Dorjee
- Bhutan Agriculture and Food Regulatory Authority, Thimphu, Bhutan.,Khesar Gyalpo University of Medical Science, Thimphu, Bhutan
| | - Tashi Tobgay
- Khesar Gyalpo University of Medical Science, Thimphu, Bhutan
| | - Wanna Chaijaroenkul
- Thammasat University, Cholangiocarcinoma, Chulabhorn International College of Medicine, Center of Excellence in Pharmacology and Molecular Biology of Malaria, Pathumthani, Thailand
| | - Kesara Na-Bangchang
- Thammasat University, Cholangiocarcinoma, Chulabhorn International College of Medicine, Center of Excellence in Pharmacology and Molecular Biology of Malaria, Pathumthani, Thailand
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96
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Panda B, Mohapatra MK, Paital S, Kumbhakar S, Dutta A, Kadam S, Salunke S, Pradhan MM, Khurana A, Nayak D, Manchanda RK. Prevalence of afebrile malaria and development of risk-scores for gradation of villages: A study from a hot-spot in Odisha. PLoS One 2019; 14:e0221223. [PMID: 31490940 PMCID: PMC6730888 DOI: 10.1371/journal.pone.0221223] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 08/01/2019] [Indexed: 11/18/2022] Open
Abstract
Introduction Malaria is a public health emergency in India and Odisha. The national malaria elimination programme aims to expedite early identification, treatment and follow-up of malaria cases in hot-spots through a robust health system, besides focusing on efficient vector control. This study, a result of mass screening conducted in a hot-spot in Odisha, aimed to assess prevalence, identify and estimate the risks and develop a management tool for malaria elimination. Methods Through a cross-sectional study and using WHO recommended Rapid Diagnostic Test (RDT), 13221 individuals were screened. Information about age, gender, education and health practices were collected along with blood sample (5 μl) for malaria testing. Altitude, forestation, availability of a village health worker and distance from secondary health center were captured using panel technique. A multi-level poisson regression model was used to analyze association between risk factors and prevalence of malaria, and to estimate risk scores. Results The prevalence of malaria was 5.8% and afebrile malaria accounted for 79 percent of all confirmed cases. Higher proportion of Pv infections were afebrile (81%). We found the prevalence to be 1.38 (1.1664–1.6457) times higher in villages where the Accredited Social Health Activist (ASHA) didn’t stay; the risk increased by 1.38 (1.0428–1.8272) and 1.92 (1.4428–2.5764) times in mid- and high-altitude tertiles. With regard to forest coverage, villages falling under mid- and highest-tertiles were 2.01 times (1.6194–2.5129) and 2.03 times (1.5477–2.6809), respectively, more likely affected by malaria. Similarly, villages of mid tertile and lowest tertile of education had 1.73 times (1.3392–2.2586) and 2.50 times (2.009–3.1244) higher prevalence of malaria. Conclusion Presence of ASHA worker in villages, altitude, forestation, and education emerged as principal predictors of malaria infection in the study area. An easy-to-use risk-scoring system for ranking villages based on these risk factors could facilitate resource prioritization for malaria elimination.
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Affiliation(s)
- Bhuputra Panda
- Indian Institute of Public Health, Bhubaneswar, Odisha, India
- * E-mail:
| | | | - Saswati Paital
- Indian Institute of Public Health, Bhubaneswar, Odisha, India
| | - Sreya Kumbhakar
- Indian Institute of Public Health, Bhubaneswar, Odisha, India
| | - Ambarish Dutta
- Indian Institute of Public Health, Bhubaneswar, Odisha, India
| | - Shridhar Kadam
- Indian Institute of Public Health, Bhubaneswar, Odisha, India
| | - Subhash Salunke
- Indian Institute of Public Health, Bhubaneswar, Odisha, India
| | - M. M. Pradhan
- Health and Family Welfare Department, Government of Odisha, Bhubaneswar, Odisha, India
| | - Anil Khurana
- Central Council for Research in Homeopathy, Ministry of AYUSH, Government of India, New Delhi, India
| | - Debadatta Nayak
- Central Council for Research in Homeopathy, Ministry of AYUSH, Government of India, New Delhi, India
| | - R. K. Manchanda
- Central Council for Research in Homeopathy, Ministry of AYUSH, Government of India, New Delhi, India
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97
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Pizzitutti F, Mena CF, Feingold B, Pan WK. Modeling asymptomatic infections and work-related human circulation as drivers of unstable malaria transmission in low-prevalence areas: A study in the Northern Peruvian Amazon. Acta Trop 2019; 197:104909. [PMID: 30703339 DOI: 10.1016/j.actatropica.2019.01.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 01/17/2019] [Accepted: 01/27/2019] [Indexed: 12/31/2022]
Abstract
BACKGROUND Despite relatively successful control campaigns, malaria remains a relevant public health problem in the Peruvian Amazon. Several studies suggest that malaria persistence in the area can be connected with a high prevalence of asymptomatic infections, which were subsequently shown to be connected with work-related exposure in areas of hyperendemic transmission. In this study, we tested the hypothesis that the infection reservoir represented by asymptomatic carriers in the northern Peruvian Amazon, combined with circular human movement to and from hyperendemic working areas, can capture the observed hypoendemic malaria transmission. METHODS We designed a set of agent-based models that represent local-scale malaria transmission in a typical riverine community in the northern Peruvian Amazon. The models include asymptomatic individuals as well as a full representation of human movements within the community and between the community and external hyperendemic working places. Several theoretical scenarios are explored to verify if and how malaria clinical immunity prevalence and human work-related movements influence the malaria morbidity registered in the community. RESULTS Agent-based simulations suggest that malaria incidence observed through passive case detection can be reproduced as exclusively generated by the asymptomatic infection reservoir. Scenarios analysis also show that, even if asymptomatic infections are completely eliminated, human movements to and from hyperendemic working areas generate a flow of imported cases that is enough to permit the persistence of transmission in the community. Simulation results were verified over a wide range of clinical immunity prevalence values and over a wide range of percentages of people working in remote hyperendemic areas. This context of unstable malaria transmission is observed to be vulnerable to severe outbreaks. CONCLUSIONS Asymptomatic malaria infection and occupational circular human movement to hyperendemic transmission areas are designated by agent-based models as possible exclusive causes of residual hypoendemic malaria transmission observed in the Peruvian Amazon. Control strategies are proposed to decrease asymptomatic infection prevalence and to block transmission from asymptomatic individuals to the malaria susceptible population.
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98
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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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99
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Reiker T, Chitnis N, Smith T. Modelling reactive case detection strategies for interrupting transmission of Plasmodium falciparum malaria. Malar J 2019; 18:259. [PMID: 31362768 PMCID: PMC6668148 DOI: 10.1186/s12936-019-2893-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 07/22/2019] [Indexed: 02/26/2023] Open
Abstract
BACKGROUND As areas move closer to malaria elimination, a combination of limited resources and increasing heterogeneity in case distribution and transmission favour a shift to targeted reactive interventions. Reactive case detection (RCD), the following up of additional individuals surrounding an index case, has the potential to target transmission pockets and identify asymptomatic cases in them. Current RCD implementation strategies vary, and it is unclear which are most effective in achieving elimination. METHODS OpenMalaria, an established individual-based stochastic model, was used to simulate RCD in a Zambia-like setting. The capacity to follow up index cases, the search radius, the initial transmission and the case management coverage were varied. Suitable settings were identified and probabilities of elimination and time to elimination estimated. The value of routinely collected prevalence and incidence data for predicting the success of RCD was assessed. RESULTS The results indicate that RCD with the aim of transmission interruption is only appropriate in settings where initial transmission is very low (annual entomological inoculation rate (EIR) 1-2 or prevalence approx. < 7-19% depending on case management levels). Every index case needs to be followed up, up to a maximum case-incidence threshold which defines the suitability threshold of settings for elimination using RCD. Increasing the search radius around index cases is always beneficial. CONCLUSIONS RCD is highly resource intensive, requiring testing and treating of 400-500 people every week for 5-10 years for a reasonable chance of elimination in a Zambia-like setting.
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Affiliation(s)
- Theresa Reiker
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, 4051, Basel, Switzerland
- University of Basel, Petersplatz 1, Basel, Switzerland
| | - Nakul Chitnis
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, 4051, Basel, Switzerland
- University of Basel, Petersplatz 1, Basel, Switzerland
| | - Thomas Smith
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, 4051, Basel, Switzerland.
- University of Basel, Petersplatz 1, Basel, Switzerland.
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100
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Surendra H, Wijayanti MA, Murhandarwati EH, Irnawati, Yuniarti T, Mardiati, Herdiana, Sumiwi ME, Hawley WA, Lobo NF, Cook J, Drakeley C, Supargiyono. Analysis of serological data to investigate heterogeneity of malaria transmission: a community-based cross-sectional study in an area conducting elimination in Indonesia. Malar J 2019; 18:227. [PMID: 31286973 PMCID: PMC6615161 DOI: 10.1186/s12936-019-2866-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 07/03/2019] [Indexed: 01/22/2023] Open
Abstract
Background Analysis of anti-malarial antibody responses has the potential to improve characterization of the variation in exposure to infection in low transmission settings, where conventional measures, such as entomological estimates and parasitaemia point prevalence become less sensitive and expensive to measure. This study evaluates the use of sero-epidemiological analysis to investigate heterogeneity of transmission in area conducting elimination in Indonesia. Methods Filter paper bloodspots and epidemiological data were collected through a community-based cross-sectional study conducted in two sub-districts in Sabang municipality, Aceh province, Indonesia in 2013. Antibody responses to merozoite surface protein 1 (MSP-119) and apical membrane antigen 1 (AMA-1) for Plasmodium falciparum and Plasmodium vivax were measured using indirect enzyme-linked immunosorbent assay (ELISA). Seroconversion rates (SCR) were estimated by fitting a simple reversible catalytic model to seroprevalence data for each antibody. Spatial analysis was performed using a Normal model (SaTScan v.9.4.2) to identify the clustering of higher values of household antibody responses. Multiple logistic regression was used to investigate factors associated with exposure. Results 1624 samples were collected from 605 households. Seroprevalence to any P. falciparum antigen was higher than to any P. vivax antigen, 6.9% (95% CI 5.8–8.2) vs 2.0% (95% CI 1.4–2.8). SCR estimates suggest that there was a significant change in P. falciparum transmission with no exposure seen in children under 5 years old. Plasmodium falciparum SCR in over 5 years old was 0.008 (95% CI 0.003–0.017) and 0.012 (95% CI 0.005–0.030) in Sukakarya and Sukajaya sub-districts, respectively. Clusters of exposure were detected for both P. falciparum and P. vivax, most of them in Sukajaya sub-district. Higher age, P. vivax seropositivity and use of long-lasting insecticide-treated bed net (LLIN) were associated with higher P. falciparum exposure. Conclusion Analysis of community-based serological data helps describe the level of transmission, heterogeneity and factors associated with malaria transmission in Sabang. This approach could be an important additional tool for malaria monitoring and surveillance in low transmission settings in Indonesia. Electronic supplementary material The online version of this article (10.1186/s12936-019-2866-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Henry Surendra
- Infection Biology Department, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK. .,Centre for Tropical Medicine, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia.
| | - Mahardika A Wijayanti
- Centre for Tropical Medicine, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia.,Department of Parasitology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia
| | - Elsa H Murhandarwati
- Centre for Tropical Medicine, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia.,Department of Parasitology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia
| | - Irnawati
- Sabang Municipal Health Office, Sabang, Aceh, Indonesia
| | | | - Mardiati
- Sabang Municipal Health Office, Sabang, Aceh, Indonesia
| | - Herdiana
- Child Survival and Development Cluster, UNICEF Aceh Field Office, Jakarta, Indonesia
| | - Maria E Sumiwi
- Child Survival and Development Cluster, UNICEF Aceh Field Office, Jakarta, Indonesia
| | - William A Hawley
- Child Survival and Development Cluster, UNICEF Indonesia Country Office, Jakarta, Indonesia
| | - Neil F Lobo
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Jackie Cook
- MRC Tropical Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Chris Drakeley
- Infection Biology Department, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Supargiyono
- Centre for Tropical Medicine, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia.,Department of Parasitology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia
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