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Benjamin-Chung J, Li H, Nguyen A, Barratt Heitmann G, Bennett A, Ntuku H, Prach LM, Tambo M, Wu L, Drakeley C, Gosling R, Mumbengegwi D, Kleinschmidt I, Smith JL, Hubbard A, van der Laan M, Hsiang MS. Extension of efficacy range for targeted malaria-elimination interventions due to spillover effects. Nat Med 2024:10.1038/s41591-024-03134-z. [PMID: 38965434 DOI: 10.1038/s41591-024-03134-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 06/13/2024] [Indexed: 07/06/2024]
Abstract
Malaria-elimination interventions aim to extinguish hotspots and prevent transmission to nearby areas. Here, we re-analyzed a cluster-randomized trial of reactive, focal interventions (chemoprevention using artemether-lumefantrine and/or indoor residual spraying with pirimiphos-methyl) delivered within 500 m of confirmed malaria index cases in Namibia to measure direct effects (among intervention recipients within 500 m) and spillover effects (among non-intervention recipients within 3 km) on incidence, prevalence and seroprevalence. There was no or weak evidence of direct effects, but the sample size of intervention recipients was small, limiting statistical power. There was the strongest evidence of spillover effects of combined chemoprevention and indoor residual spraying. Among non-recipients within 1 km of index cases, the combined intervention reduced malaria incidence by 43% (95% confidence interval, 20-59%). In analyses among non-recipients within 3 km of interventions, the combined intervention reduced infection prevalence by 79% (6-95%) and seroprevalence, which captures recent infections and has higher statistical power, by 34% (20-45%). Accounting for spillover effects increased the cost-effectiveness of the combined intervention by 42%. Targeting hotspots with combined chemoprevention and vector-control interventions can indirectly benefit non-recipients up to 3 km away.
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Affiliation(s)
- Jade Benjamin-Chung
- Department of Epidemiology and Population Health, Stanford University, Stanford, CA, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, USA.
| | - Haodong Li
- Division of Biostatistics, University of California, Berkeley, Berkeley, CA, USA
| | - Anna Nguyen
- Department of Epidemiology and Population Health, Stanford University, Stanford, CA, USA
| | | | - Adam Bennett
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, San Francisco, CA, USA
- PATH, Seattle, WA, USA
| | - Henry Ntuku
- Malaria Elimination Initiative, Global Health Group, 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
| | - Munyaradzi Tambo
- Multidisciplinary Research Centre, University of Namibia, Windhoek, Namibia
| | - Lindsey Wu
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Roly Gosling
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, San Francisco, CA, USA
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | | | - Immo Kleinschmidt
- MRC International Statistics and Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
- Wits Research Institute for Malaria, Wits/SAMRC 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
| | - Jennifer L Smith
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, San Francisco, CA, USA
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA
| | - Alan Hubbard
- Division of Biostatistics, University of California, Berkeley, Berkeley, CA, USA
| | - Mark van der Laan
- Division of Biostatistics, University of California, Berkeley, Berkeley, CA, USA
| | - Michelle S Hsiang
- Chan Zuckerberg Biohub, San Francisco, CA, USA
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, San Francisco, CA, USA
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA
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Ferriss E, Mharakurwa S, Munyati S, Gwanzura L, Hast MA, Moulton LH, Wesolowski A, Moss WJ. Malaria Transmission at The Zimbabwe-Mozambique Border: An Observational Study of Parasitemia by Travel History and Household Location. Am J Trop Med Hyg 2024; 111:35-42. [PMID: 38772357 PMCID: PMC11229651 DOI: 10.4269/ajtmh.23-0466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Accepted: 03/04/2024] [Indexed: 05/23/2024] Open
Abstract
Cross-border human population movement contributes to malaria transmission in border regions, impeding national elimination. However, its impact in low-to-moderate transmission settings is not well characterized. This community-based study in Mutasa District, Zimbabwe, estimated the association of parasite prevalence with self-reported overnight travel to Mozambique and household distance to the border from 2012-2020. A fully adjusted Poisson regression model with robust variance estimation was fit using active surveillance data. The population attributable fraction of parasite prevalence from overnight travel was also estimated. The relative risk of testing positive for malaria by rapid diagnostic test declined 14% (prevalence ratio [PR] = 0.86, 95% CI = 0.81-0.92) per kilometer from the border up to 12 km away. Travel to Mozambique was associated with a 157% increased risk (PR = 2.57, 95% CI = 1.38-4.78), although only 5.8% of cases were attributable to overnight travel (95% CI = -1.1% to 12.7%), reflecting infrequent overnight trips (1.3% of visits). This study suggests that transmission in eastern Zimbabwe is driven by increasingly conducive social or environmental conditions approaching the border and low levels of importation from overnight travel. Although day trips to Mozambique during peak biting hours were not assessed, the contribution of such trips to ongoing transmission may be significant. Future malaria control efforts should prioritize high coverage of existing interventions and continued support for community health workers and health facilities at the border, which provide free case management.
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Affiliation(s)
- Ellen Ferriss
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | - Shungu Munyati
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Lovemore Gwanzura
- Biomedical Research and Training Institute, Harare, Zimbabwe
- University of Zimbabwe, Harare, Zimbabwe
| | - Marisa A. Hast
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Lawrence H. Moulton
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Amy Wesolowski
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - William J. Moss
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
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Rerolle F, Jacobson JO, Smith Gueye C, Bennett A, Carrillo S, Ntuku H, Smith JL. Estimating the size of populations at risk for malaria: a case study in cattle herders and agricultural workers in Northern Namibia. Sci Rep 2024; 14:7160. [PMID: 38531921 DOI: 10.1038/s41598-024-56810-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 03/11/2024] [Indexed: 03/28/2024] Open
Abstract
Cattle herders and agricultural workers have been identified has key high-risk populations for malaria in northern Namibia. Population size estimates for these groups are lacking but are important for planning, monitoring and evaluating the effectiveness of targeted strategies towards malaria elimination in the region. In this analysis, we extend population size estimation methods routinely used in HIV research, specifically social mapping and multiple source capture-recapture, to the context of malaria to estimate how many cattle herders and agricultural workers lived in two regions of northern Namibia over the course of the 2019-2020 malaria season. Both methods estimated two to three times more agricultural workers than cattle herders but size estimates based on the multiple source capture-recapture method were two to three times greater than the mapping-based, highlighting important methodological considerations to apply such methods to these highly mobile populations. In particular, we compared open versus closed populations assumptions for the capture-recapture method and assessed the impact of sensitivity analyses on the procedure to link records across multiple data sources on population size estimates. Our results are important for national control programs to target their resources and consider integrating routine population size estimation of high risk populations in their surveillance activities.
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Affiliation(s)
- Francois Rerolle
- Malaria Elimination Initiative, The Global Health Group, University of California, San Francisco, CA, USA.
| | - Jerry O Jacobson
- Malaria Elimination Initiative, The Global Health Group, University of California, San Francisco, CA, USA
| | - Cara Smith Gueye
- Malaria Elimination Initiative, The Global Health Group, University of California, San Francisco, CA, USA
| | - Adam Bennett
- Malaria Elimination Initiative, The Global Health Group, University of California, San Francisco, CA, USA
| | - Sidney Carrillo
- Malaria Elimination Initiative, The Global Health Group, University of California, San Francisco, CA, USA
| | - Henry Ntuku
- Malaria Elimination Initiative, The Global Health Group, University of California, San Francisco, CA, USA
| | - Jennifer L Smith
- Malaria Elimination Initiative, The Global Health Group, University of California, San Francisco, CA, USA
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Abdalal SA, Yukich J, Andrinopoulos K, Alghanmi M, Wakid MH, Zawawi A, Harakeh S, Altwaim SA, Gattan H, Baakdah F, Gaddoury MA, Niyazi HA, Mokhtar JA, Alruhaili MH, Alsaady I, Alhabbab R, Alfaleh M, Hashem AM, Alahmadey ZZ, Keating J. Livelihood activities, human mobility, and risk of malaria infection in elimination settings: a case-control study. Malar J 2023; 22:53. [PMID: 36782234 PMCID: PMC9926773 DOI: 10.1186/s12936-023-04470-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 01/24/2023] [Indexed: 02/15/2023] Open
Abstract
BACKGROUND Livelihood activities and human movements participate in the epidemiology of vector-borne diseases and influence malaria risk in elimination settings. In Saudi Arabia, where malaria transmission intensity varies geographically, it is vital to understand the components driving transmission within specific areas. In addition, shared social, behavioural, and occupational characteristics within communities may provoke the risk of malaria infection. This study aims to understand the relationship between human mobility, livelihood activities, and the risk of malaria infection in the border region of Jazan to facilitate further strategic malaria interventions. In addition, the study will complement and reinforce the existing efforts to eliminate malaria on the Saudi and Yemen border by providing a deeper understanding of human movement and livelihood activities. METHODS An unmatched case-control study was conducted. A total of 261 participants were recruited for the study, including 81 cases of confirmed malaria through rapid diagnostic tests (RDTs) and microscopy and 180 controls in the Baish Governorate in Jazan Provinces, Saudi Arabia. Individuals who received malaria tests were interviewed regarding their livelihood activities and recent movement (travel history). A questionnaire was administered, and the data was captured electronically. STATA software version 16 was used to analyse the data. Bivariate and multivariate analyses were conducted to determine if engaging in agricultural activities such as farming and animal husbandry, recent travel history outside of the home village within the last 30 days and participating in spiritual gatherings were related to malaria infection status. RESULTS A logistical regression model was used to investigate components associated with malaria infection. After adjusting several confounding factors, individuals who reported travelling away from their home village in the last 30 days OR 11.5 (95% CI 4.43-29.9), and those who attended a seasonal night spiritual gathering OR 3.04 (95% CI 1.10-8.42), involved in animal husbandry OR 2.52 (95% CI 1.10-5.82), and identified as male OR 4.57 (95% CI 1.43-14.7), were more likely to test positive for malaria infection. CONCLUSION Human movement and livelihood activities, especially at nighttime, should be considered malaria risk factors in malaria elimination settings, mainly when the targeted area is limited to a confined borderland area.
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Affiliation(s)
- Shaymaa A. Abdalal
- grid.412125.10000 0001 0619 1117Department of Medical Microbiology and Parasitology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Joshua Yukich
- grid.265219.b0000 0001 2217 8588School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA USA
| | - Katherine Andrinopoulos
- grid.265219.b0000 0001 2217 8588School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA USA
| | - Maimonah Alghanmi
- grid.412125.10000 0001 0619 1117Vaccines and Immunotherapy Unit, King Fahd Medical Research Centre, King Abdulaziz University, Jeddah, Saudi Arabia ,grid.412125.10000 0001 0619 1117Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Majed H. Wakid
- grid.412125.10000 0001 0619 1117Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia ,grid.412125.10000 0001 0619 1117Special Infectious Agents Unit, King Fahd Medical Research Centre, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Ayat Zawawi
- grid.412125.10000 0001 0619 1117Vaccines and Immunotherapy Unit, King Fahd Medical Research Centre, King Abdulaziz University, Jeddah, Saudi Arabia ,grid.412125.10000 0001 0619 1117Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Steve Harakeh
- grid.412125.10000 0001 0619 1117King Fahd Medical Research Centre, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Sarah A. Altwaim
- grid.412125.10000 0001 0619 1117Department of Medical Microbiology and Parasitology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia ,grid.412125.10000 0001 0619 1117Special Infectious Agents Unit, King Fahd Medical Research Centre, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Hattan Gattan
- grid.412125.10000 0001 0619 1117Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia ,grid.412125.10000 0001 0619 1117Special Infectious Agents Unit, King Fahd Medical Research Centre, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Fadi Baakdah
- grid.412125.10000 0001 0619 1117Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia ,grid.412125.10000 0001 0619 1117Special Infectious Agents Unit, King Fahd Medical Research Centre, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mahmoud A. Gaddoury
- grid.412125.10000 0001 0619 1117Department of Community Medicine, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Hatoon A. Niyazi
- grid.412125.10000 0001 0619 1117Department of Medical Microbiology and Parasitology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Jawahir A. Mokhtar
- grid.412125.10000 0001 0619 1117Department of Medical Microbiology and Parasitology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mohammed H. Alruhaili
- grid.412125.10000 0001 0619 1117Department of Medical Microbiology and Parasitology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia ,grid.412125.10000 0001 0619 1117Special Infectious Agents Unit, King Fahd Medical Research Centre, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Isra Alsaady
- grid.412125.10000 0001 0619 1117Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia ,grid.412125.10000 0001 0619 1117Special Infectious Agents Unit, King Fahd Medical Research Centre, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Rowa Alhabbab
- grid.412125.10000 0001 0619 1117Vaccines and Immunotherapy Unit, King Fahd Medical Research Centre, King Abdulaziz University, Jeddah, Saudi Arabia ,grid.412125.10000 0001 0619 1117Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mohamed Alfaleh
- grid.412125.10000 0001 0619 1117Vaccines and Immunotherapy Unit, King Fahd Medical Research Centre, King Abdulaziz University, Jeddah, Saudi Arabia ,grid.412125.10000 0001 0619 1117Department of Pharmaceutics, Faculty of Pharmacy, King Abdulaziz University, Jeddah, 21589 Saudi Arabia
| | - Anwar M. Hashem
- grid.412125.10000 0001 0619 1117Department of Medical Microbiology and Parasitology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia ,grid.412125.10000 0001 0619 1117Vaccines and Immunotherapy Unit, King Fahd Medical Research Centre, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Ziab Zakey Alahmadey
- grid.415696.90000 0004 0573 9824Microbiology and Serology Departments, Al-Ansar Hospital, Ministry of Health, Medina, Saudi Arabia
| | - Joseph Keating
- grid.265219.b0000 0001 2217 8588School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA USA
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Abdalal SA, Yukich J, Andrinoplous K, Harakeh S, Altwaim SA, Gattan H, Carter B, Shammaky M, Niyazi HA, Alruhaili MH, Keating J. An insight to better understanding cross border malaria in Saudi Arabia. Malar J 2023; 22:37. [PMID: 36732819 PMCID: PMC9893606 DOI: 10.1186/s12936-023-04467-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Accepted: 01/23/2023] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Border malaria is a major obstacle for the malaria elimination in Saudi Arabia. Today, the southern border of Saudi Arabia is a region where malaria cases are resurging, and malaria control is dwindling mainly due to the humanitarian crisis and the conflict in Yemen. This study analyses the current border malaria epidemiology along the southern border of Saudi Arabia from 2015 to 2018. METHODS All reported cases maintained by the malaria elimination centres in Aledabi and Baish, Jazan Province, Saudi Arabia, from 2015 to 2018 were analysed to examine the epidemiological changes over time. Pearson's Chi-Square test of differences was utilized to assess differences between the characteristics of imported and local causes and between border cases. A logistic regression model was used to predict imported status was related to living along side of the border area. RESULTS A total of 3210 malaria cases were reported in Baish and Aledabi malaria centres between 2015 and 2018, of which 170 were classified as local cases and 3040 were classified as imported cases. Reported malaria cases were mainly among males, within the imported cases 61.5% (1868/3039) were residents of the border areas. CONCLUSIONS Given the complexity of cross-border malaria, creating a malaria buffer zone that covers a certain margin from both sides of the border would allow for a joint force, cross-border malaria elimination programme. To initiate a malaria elimination activity and cases reported as belonging to this zone, rather than being pushed from one country to the other, would allow malaria elimination staff to work collaboratively with local borderland residents and other stakeholders to come up with innovative solutions to combat malaria and reach malaria-free borders.
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Affiliation(s)
- Shaymaa A. Abdalal
- grid.412126.20000 0004 0607 9688Department of Medical Microbiology and Parasitology, Faculty of Medicine, King Abdulaziz University and King Abdulaziz University Hospital, Jeddah, Saudi Arabia
| | - Joshua Yukich
- grid.265219.b0000 0001 2217 8588Tulane University School of Public Health and Tropical Medicine, New Orleans, LA USA
| | - Katherine Andrinoplous
- grid.265219.b0000 0001 2217 8588Tulane University School of Public Health and Tropical Medicine, New Orleans, LA USA
| | - Steve Harakeh
- Saudi Arabia Ministry of Health, Jazan, Saudi Arabia
| | - Sarah A. Altwaim
- grid.412126.20000 0004 0607 9688Department of Medical Microbiology and Parasitology, Faculty of Medicine, King Abdulaziz University and King Abdulaziz University Hospital, Jeddah, Saudi Arabia
| | - Hattan Gattan
- grid.412125.10000 0001 0619 1117Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Brendan Carter
- grid.265219.b0000 0001 2217 8588Tulane University School of Public Health and Tropical Medicine, New Orleans, LA USA
| | | | - Hatoon A. Niyazi
- grid.412126.20000 0004 0607 9688Department of Medical Microbiology and Parasitology, Faculty of Medicine, King Abdulaziz University and King Abdulaziz University Hospital, Jeddah, Saudi Arabia
| | - Mohammed H. Alruhaili
- grid.412126.20000 0004 0607 9688Department of Medical Microbiology and Parasitology, Faculty of Medicine, King Abdulaziz University and King Abdulaziz University Hospital, Jeddah, Saudi Arabia
| | - Joseph Keating
- grid.265219.b0000 0001 2217 8588Tulane University School of Public Health and Tropical Medicine, New Orleans, LA USA
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Zowonoo F, Iverson G, Doyle M, Richards SL. Retrospective spatiotemporal analysis of malaria cases reported between 2000 and 2020 in North Carolina, USA. Travel Med Infect Dis 2023; 51:102505. [PMID: 36427707 DOI: 10.1016/j.tmaid.2022.102505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 10/27/2022] [Accepted: 11/15/2022] [Indexed: 11/25/2022]
Abstract
BACKGROUND There are 1,000-2,000 cases of malaria diagnosed in the United States annually and most are imported. METHODS Malaria cases reported between 2000 and 2020 in North Carolina (NC) were analyzed (NC Department of Health and Human Services, Division of Public Health). Differences in numbers of NC malaria cases were further analyzed by year, month, county, gender, age, and country of origin. RESULTS Most cases originated from travelers visiting Africa and returning to NC (i.e., Mecklenburg [N = 162 cases], Wake [N = 153], Guilford [N = 103], Durham [N = 74], and Cumberland [N = 41] Counties). Per capita analysis (i.e., per 100,000 population) was used to correct for differences in NC county population sizes and Durham (N = 22.8), Guilford (N = 19.0), Onslow (N = 14.7), Mecklenburg (N = 14.5), Wake (N = 13.5), Orange (N = 12.8) and Cumberland (N = 12.2) Counties showed the highest cases. Malaria was more prevalent among males (N = 532) relative to females (N = 245), and this difference was statistically significant. CONCLUSIONS Travelers visiting malaria-endemic regions should be educated on malaria prevention measures (e.g., chemoprophylaxis, mosquito repellent). These measures should be readily available to travelers. The malaria registry in NC should be improved by requiring additional data related to imported malaria cases.
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Affiliation(s)
- Felix Zowonoo
- Environmental Health Sciences Program, Department of Health Education and Promotion, College of Health and Human Performance, East Carolina University, Greenville, NC, USA
| | - Guy Iverson
- Environmental Health Sciences Program, Department of Health Education and Promotion, College of Health and Human Performance, East Carolina University, Greenville, NC, USA
| | - Michael Doyle
- North Carolina Department of Health and Human Services, Division of Public Health, Communicable Disease Branch, Raleigh, NC, USA
| | - Stephanie L Richards
- Environmental Health Sciences Program, Department of Health Education and Promotion, College of Health and Human Performance, East Carolina University, Greenville, NC, USA.
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Mon NTS, Tangpukdee N, Charunwatthana P, Boonnak K, Krudsood S, Kano S, Wilairatana P, Leowattana W. Mimicking platelet indices in patients with malaria and dengue hemorrhagic fever: characteristics and clinical applications. Trop Med Health 2022; 50:76. [PMID: 36221147 PMCID: PMC9552151 DOI: 10.1186/s41182-022-00467-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 10/01/2022] [Indexed: 11/17/2022] Open
Abstract
Background Although platelet indices are routinely available using automated blood cell counters, the clinical applications of these parameters for malaria and dengue hemorrhagic fever (DHF) have not been substantially implemented. We conducted this study to investigate the potential role of platelet indices as a prognostic marker in adult patients with Plasmodium vivax malaria, Plasmodium falciparum malaria, and DHF admitted to the Hospital for Tropical Diseases, Bangkok, Thailand. Methods We enrolled 219 eligible patients, comprising 96 with P. falciparum malaria, 71 with P. vivax malaria, and 52 with DHF. We evaluated the study groups’ baseline clinical features and alterations of platelet indices during the first 4 days of admission. Results Upon admission, the initial laboratory findings showed no statistically significant difference in platelet count (PC), plateletcrit (PCT), or platelet distribution width (PDW) between patients with P. vivax and P. falciparum; however, mean platelet volume (MPV) was significantly higher in patients with P. falciparum. Comparisons of the initial platelet indices in malaria and DHF showed that only PC and PCT were significantly lower in DHF. Although MPV in DHF tended to be lower than in malaria, a statistically significant difference was observed only with P. falciparum. Moreover, the results also showed no significant alterations in the platelet indices among the study groups during the first 4 days of admission. Conclusions and recommendations Clinical presentations of DHF and malaria are nonspecific and may overlap with other common tropical diseases. Alterations of initial platelet indices may be investigated in P. vivax and P. falciparum malaria mimicking DHF. Although a significant reduction in PC and PCT in DHF might be a clue for differential diagnosis of malaria, the use of MPV and PDW might be impractical. We suggest that appropriate laboratory diagnoses for malaria and dengue infections are still needed for the differential diagnosis of acute febrile patients who have a risk of malaria or dengue infections. To clarify the clinical utility of platelet indices in patients with dengue and malaria, further studies are required that particularly include patients with different severities, geographical areas, and levels of health care settings.
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Affiliation(s)
- Nant The Su Mon
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Bangkok, Thailand
| | - Noppadon Tangpukdee
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Bangkok, Thailand.
| | - Prakaykaew Charunwatthana
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Bangkok, Thailand.,Mahidol Oxford Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kobporn Boonnak
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.,Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Srivicha Krudsood
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Shigeyuki Kano
- Department of Tropical Medicine and Malaria, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Polrat Wilairatana
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Bangkok, Thailand.,WHO Collaborating Centre for Case Management, Training and Research on Malaria, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Wattana Leowattana
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Bangkok, Thailand.
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8
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Factors related to long-lasting insecticidal net (LLIN) use during travel in western Kenya: A descriptive analysis. Travel Med Infect Dis 2022; 47:102291. [DOI: 10.1016/j.tmaid.2022.102291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 02/15/2022] [Accepted: 02/23/2022] [Indexed: 11/20/2022]
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Dunning J, Aung NKZ, Ward A, Aye MM, Lourenço C, Gallalee S, Lavenberg S, Le Menach A, Tun MM, Thi A. Key factors associated with malaria infection among patients seeking care through the public sector in endemic townships of Ayeyarwady Region, Myanmar. Malar J 2022; 21:86. [PMID: 35292042 PMCID: PMC8922824 DOI: 10.1186/s12936-022-04088-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 02/15/2022] [Indexed: 11/10/2022] Open
Abstract
Background Ayeyarwady Region in Myanmar has made significant progress towards malaria elimination, with cases decreasing from 12,312 in 2015 to 122 in 2019. As transmission declines, malaria becomes increasingly focalized both in geographic hotspots and among population groups sharing certain risk factors. Developing a thorough profile of high-risk activities associated with malaria infections is critical to ensure intervention approaches are evidence-based. Methods A test-negative study was conducted from September 2017 to May 2018 in Ngaputaw, Pathein and Thabaung townships in Ayeyarwady Region. Patients that presented to selected public facilities or community health volunteers with fever answered survey questions on demographic and behavioural risk factors, including exposure to malaria interventions, and were assigned to case and control groups based on the result of a malaria rapid diagnostic test. A random-effects logistic regression model adjusted for clustering at the facility level, as well as any variables along the causal pathway described by a directed acyclic graph, was used to determine odds ratios and association with malaria infections. Results A total of 119 cases and 1744 controls were recruited from 41 public facilities, with a mean age of 31.3 and 63.7% male. Higher risk groups were identified as males (aOR 1.8, 95% CI 1.2–2.9) and those with a worksite located within the forest (aOR 2.8, 95% CI 1.4–5.3), specifically working in the logging (aOR 2.7, 95% CI 1.5–4.6) and rubber plantation (aOR 3.0, 95% CI 1.4–6.8) industries. Additionally, links between forest travel and malaria were observed, with risk factors identified to be sleeping in the forest within the past month (aOR 2.6, 95% CI 1.1–6.3), and extended forest travel with durations from 3 to 14 days (aOR 8.6, 95% CI 3.5–21.4) or longer periods (aOR 8.4, 95% CI 3.2–21.6). Conclusion Malaria transmission is highly focalized in Ayeyarwady, and results illustrate the need to target interventions to the most at-risk populations of working males and forest goers. It will become increasingly necessary to ensure full intervention coverage of at-risk populations active in forested areas as Myanmar moves closer to malaria elimination goals. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04088-8.
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Affiliation(s)
| | | | - Abigail Ward
- Clinton Health Access Initiative, Boston, MA, USA
| | - Moe Moe Aye
- Clinton Health Access Initiative, Yangon, Myanmar
| | | | | | | | | | - Myat Min Tun
- Myanmar Vector Borne Disease Control Program, Ministry of Health and Sports, Nay Pyi Taw, Myanmar
| | - Aung Thi
- Myanmar Vector Borne Disease Control Program, Ministry of Health and Sports, Nay Pyi Taw, Myanmar
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Wu L, Hsiang MS, Prach LM, Schrubbe L, Ntuku H, Dufour MSK, Whittemore B, Scott V, Yala J, Roberts KW, Patterson C, Biggs J, Hall T, Tetteh KK, Gueye CS, Greenhouse B, Bennett A, Smith JL, Katokele S, Uusiku P, Mumbengegwi D, Gosling R, Drakeley C, Kleinschmidt I. Serological evaluation of the effectiveness of reactive focal mass drug administration and reactive vector control to reduce malaria transmission in Zambezi Region, Namibia: Results from a secondary analysis of a cluster randomised trial. EClinicalMedicine 2022; 44:101272. [PMID: 35198913 PMCID: PMC8851292 DOI: 10.1016/j.eclinm.2022.101272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 12/20/2021] [Accepted: 01/06/2022] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Due to challenges in measuring changes in malaria at low transmission, serology is increasingly being used to complement clinical and parasitological surveillance. Longitudinal studies have shown that serological markers, such as Etramp5.Ag1, can reflect spatio-temporal differences in malaria transmission. However, these markers have yet to be used as endpoints in intervention trials. METHODS Based on data from a 2017 cluster randomised trial conducted in Zambezi Region, Namibia, evaluating the effectiveness of reactive focal mass drug administration (rfMDA) and reactive vector control (RAVC), this study conducted a secondary analysis comparing antibody responses between intervention arms as trial endpoints. Antibody responses were measured on a multiplex immunoassay, using a panel of eight serological markers of Plasmodium falciparum infection - Etramp5.Ag1, GEXP18, HSP40.Ag1, Rh2.2030, EBA175, PfMSP119, PfAMA1, and PfGLURP.R2. FINDINGS Reductions in sero-prevalence to antigens Etramp.Ag1, PfMSP119, Rh2.2030, and PfAMA1 were observed in study arms combining rfMDA and RAVC, but only effects for Etramp5.Ag1 were statistically significant. Etramp5.Ag1 sero-prevalence was significantly lower in all intervention arms. Compared to the reference arms, adjusted prevalence ratio (aPR) for Etramp5.Ag1 was 0.78 (95%CI 0.65 - 0.91, p = 0.0007) in the rfMDA arms and 0.79 (95%CI 0.67 - 0.92, p = 0.001) in the RAVC arms. For the combined rfMDA plus RAVC intervention, aPR was 0.59 (95%CI 0.46 - 0.76, p < 0.0001). Significant reductions were also observed based on continuous antibody responses. Sero-prevalence as an endpoint was found to achieve higher study power (99.9% power to detect a 50% reduction in prevalence) compared to quantitative polymerase chain reaction (qPCR) prevalence (72.9% power to detect a 50% reduction in prevalence). INTERPRETATION While the observed relative reduction in qPCR prevalence in the study was greater than serology, the use of serological endpoints to evaluate trial outcomes measured effect size with improved precision and study power. Serology has clear application in cluster randomised trials, particularly in settings where measuring clinical incidence or infection is less reliable due to seasonal fluctuations, limitations in health care seeking, or incomplete testing and reporting. FUNDING This study was supported by Novartis Foundation (A122666), the Bill & Melinda Gates Foundation (OPP1160129), and the Horchow Family Fund (5,300,375,400).
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Affiliation(s)
- Lindsey Wu
- London School of Hygiene and Tropical Medicine, Faculty of Infectious Tropical Diseases, Department of Infection Biology, London, United Kingdom of Great Britain
- Corresponding author.
| | - Michelle S. Hsiang
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States of America
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, CA, United States of America
- 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, United States of America
| | - Leah Schrubbe
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, CA, United States of America
| | - Henry Ntuku
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, CA, United States of America
| | - 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, United States of America
| | - Valerie Scott
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, CA, United States of America
| | - Joy Yala
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, CA, United States of America
| | - Kathryn W. Roberts
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, CA, United States of America
| | - Catriona Patterson
- London School of Hygiene and Tropical Medicine, Faculty of Infectious Tropical Diseases, Department of Infection Biology, London, United Kingdom of Great Britain
| | - Joseph Biggs
- London School of Hygiene and Tropical Medicine, Faculty of Infectious Tropical Diseases, Department of Infection Biology, London, United Kingdom of Great Britain
| | - Tom Hall
- St. George's University of London, London, UK
| | - Kevin K.A. Tetteh
- London School of Hygiene and Tropical Medicine, Faculty of Infectious Tropical Diseases, Department of Infection Biology, London, United Kingdom of Great Britain
| | - Cara Smith Gueye
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, CA, United States of America
| | - Bryan Greenhouse
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Adam Bennett
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, CA, United States of America
| | - Jennifer L. Smith
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, CA, United States of America
| | - 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
| | - 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, United States of America
| | - Chris Drakeley
- London School of Hygiene and Tropical Medicine, Faculty of Infectious Tropical Diseases, Department of Infection Biology, London, United Kingdom of Great Britain
| | - Immo Kleinschmidt
- London School of Hygiene and Tropical Medicine, Faculty of Epidemiology and Population Health, Department of Infectious Disease Epidemiology, London, UK
- Research Council Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Wits Institute for Malaria Research, Faculty of Health Science, University of Witwatersrand, Johannesburg, South Africa
- Southern African Development Community Malaria Elimination Eight Secretariat, Windhoek, Namibia
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Giannone B, Hedrich N, Schlagenhauf P. Imported malaria in Switzerland, (1990-2019): A retrospective analysis. Travel Med Infect Dis 2021; 45:102251. [PMID: 34973453 DOI: 10.1016/j.tmaid.2021.102251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/23/2021] [Accepted: 12/26/2021] [Indexed: 10/19/2022]
Abstract
BACKGROUND Malaria is a life-threatening, mosquito-borne parasitic disease, caused by Plasmodium spp. It is a major public health issue. Malaria in Switzerland is primarily "imported" by infected international travellers, migrants, and asylum-seekers. METHOD We investigated the epidemiology and characteristics of imported malaria in Switzerland in the period between 1990 and 2019 using data from the Swiss Federal Office of Public Health (BAG). We also obtained traveller statistics from the World Tourism Organization (UNWTO). RESULTS During the last thirty years a total of 8'439 malaria cases and 52 deaths were reported in Switzerland. The main origin of infection was West Africa, followed by Central Africa and East Africa. The profile of malaria in migrants in Switzerland has changed, reflecting variation in migrant flows. The estimated risk of malaria in travellers sank significantly over the time frame of the study (p < 0.001, 95% CI -0.076 to -0.043). CONCLUSIONS Travel medicine should focus on West Africa, the main source of malaria in Switzerland. Despite most cases and all but one death being caused by Plasmodium falciparum, Plasmodium vivax remains a threat for travellers and is associated with complex prevention and therapy regimens. Public health authorities need to pre-empt the need for malaria screening, prevention and treatment based on the profile of migrant waves from malaria endemic areas including Eritrea and Afghanistan arriving in Europe.
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Affiliation(s)
- Bodo Giannone
- Kantonsspital St.Gallen, Emergency Department, Switzerland
| | - Nadja Hedrich
- University of Zürich, Epidemiology, Biostatistics and Prevention Institute, Switzerland
| | - Patricia Schlagenhauf
- University of Zürich, Epidemiology, Biostatistics and Prevention Institute, WHO Collaborating Centre for Travellers' Health, Department of Global and Public Health, MilMedBiol Competence Centre, Hirschengraben 84, 8001, Zürich, Switzerland.
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Threats to the effectiveness of insecticide-treated bednets for malaria control: thinking beyond insecticide resistance. LANCET GLOBAL HEALTH 2021; 9:e1325-e1331. [PMID: 34216565 DOI: 10.1016/s2214-109x(21)00216-3] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/03/2021] [Accepted: 04/23/2021] [Indexed: 12/22/2022]
Abstract
From 2004 to 2019, insecticide-treated bednets (ITNs) have been the most effective tool for reducing malaria morbidity and mortality in sub-Saharan Africa. Recently, however, the decline in malaria cases and deaths has stalled. Some suggest that this inertia is due to increasing resistance in malaria vectors to the pyrethroid insecticides used for treating ITNs. However, there is presently little evidence to reach this conclusion and we therefore recommend that a broader perspective to evaluate ITN effectiveness in terms of access to nets, use of nets, bioefficacy, and durability should be taken. We argue that a single focus on insecticide resistance misses the bigger picture. To improve the effects of ITNs, net coverage should increase by increasing funding for programmes, adopting improved strategies for increasing ITN uptake, and enhancing the longevity of the active ingredients and the physical integrity of nets, while simultaneously accelerating the development and evaluation of novel vector control tools.
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Smith JL, Mumbengegwi D, Haindongo E, Cueto C, Roberts KW, Gosling R, Uusiku P, Kleinschmidt I, Bennett A, Sturrock HJ. Malaria risk factors in northern Namibia: The importance of occupation, age and mobility in characterizing high-risk populations. PLoS One 2021; 16:e0252690. [PMID: 34170917 PMCID: PMC8232432 DOI: 10.1371/journal.pone.0252690] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 05/20/2021] [Indexed: 11/19/2022] Open
Abstract
In areas of low and unstable transmission, malaria cases occur in populations with lower access to malaria services and interventions, and in groups with specific malaria risk exposures often away from the household. In support of the Namibian National Vector Borne Disease Program's drive to better target interventions based upon risk, we implemented a health facility-based case control study aimed to identify risk factors for symptomatic malaria in Zambezi Region, northern Namibia. A total of 770 febrile individuals reporting to 6 health facilities and testing positive by rapid diagnostic test (RDT) between February 2015 and April 2016 were recruited as cases; 641 febrile individuals testing negative by RDT at the same health facilities through June 2016 were recruited as controls. Data on socio-demographics, housing construction, overnight travel, use of malaria prevention and outdoor behaviors at night were collected through interview and recorded on a tablet-based questionnaire. Remotely-sensed environmental data were extracted for geo-located village residence locations. Multivariable logistic regression was conducted to identify risk factors and latent class analyses (LCA) used to identify and characterize high-risk subgroups. The majority of participants (87% of cases and 69% of controls) were recruited during the 2016 transmission season, an outbreak year in Southern Africa. After adjustment, cases were more likely to be cattle herders (Adjusted Odds Ratio (aOR): 4.46 95%CI 1.05-18.96), members of the police or other security personnel (aOR: 4.60 95%CI: 1.16-18.16), and pensioners/unemployed persons (aOR: 2.25 95%CI 1.24-4.08), compared to agricultural workers (most common category). Children (aOR 2.28 95%CI 1.13-4.59) and self-identified students were at higher risk of malaria (aOR: 4.32 95%CI 2.31-8.10). Other actionable risk factors for malaria included housing and behavioral characteristics, including traditional home construction and sleeping in an open structure (versus modern structure: aOR: 2.01 95%CI 1.45-2.79 and aOR: 4.76 95%CI: 2.14-10.57); cross border travel in the prior 30 days (aOR: 10.55 95%CI 2.94-37.84); and outdoor agricultural work at night (aOR: 2.09 95%CI 1.12-3.87). Malaria preventive activities were all protective and included personal use of an insecticide treated net (ITN) (aOR: 0.61 95%CI 0.42-0.87), adequate household ITN coverage (aOR: 0.63 95%CI 0.42-0.94), and household indoor residual spraying (IRS) in the past year (versus never sprayed: (aOR: 0.63 95%CI 0.44-0.90). A number of environmental factors were associated with increased risk of malaria, including lower temperatures, higher rainfall and increased vegetation for the 30 days prior to diagnosis and residing more than 5 minutes from a health facility. LCA identified six classes of cases, with class membership strongly correlated with occupation, age and select behavioral risk factors. Use of ITNs and IRS coverage was similarly low across classes. For malaria elimination these high-risk groups will need targeted and tailored intervention strategies, for example, by implementing alternative delivery methods of interventions through schools and worksites, as well as the use of specific interventions that address outdoor transmission.
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Affiliation(s)
- Jennifer L. Smith
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco (UCSF), San Francisco, California, United States of America
| | - Davis Mumbengegwi
- Multidisciplinary Research Centre, University of Namibia, Windhoek, Namibia
| | - Erastus Haindongo
- School of Medicine, Faculty of Health Sciences, University of Namibia, Windhoek, Namibia
| | - Carmen Cueto
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco (UCSF), San Francisco, California, United States of America
| | - Kathryn W. Roberts
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco (UCSF), San Francisco, California, United States of America
| | - Roly Gosling
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco (UCSF), San Francisco, California, United States of America
| | - Petrina Uusiku
- National Ministry of Health and Social Services, Windhoek, Namibia
| | - Immo Kleinschmidt
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Adam Bennett
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco (UCSF), San Francisco, California, United States of America
| | - Hugh J. Sturrock
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco (UCSF), San Francisco, California, United States of America
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Reyes RA, Fornace KM, Macalinao MLM, Boncayao BL, De La Fuente ES, Sabanal HM, Bareng APN, Medado IAP, Mercado ES, Baquilod MS, Luchavez JS, Hafalla JCR, Drakeley CJ, Espino FEJ. Enhanced Health Facility Surveys to Support Malaria Control and Elimination across Different Transmission Settings in the Philippines. Am J Trop Med Hyg 2021; 104:968-978. [PMID: 33534761 PMCID: PMC7941801 DOI: 10.4269/ajtmh.20-0814] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 10/15/2020] [Indexed: 12/12/2022] Open
Abstract
Following substantial progress in malaria control in the Philippines, new surveillance approaches are needed to identify and target residual malaria transmission. This study evaluated an enhanced surveillance approach using rolling cross-sectional surveys of all health facility attendees augmented with molecular diagnostics and geolocation. Facility surveys were carried out in three sites representing different transmission intensities: Morong, Bataan (pre-elimination), Abra de Ilog, Occidental Mindoro (stable medium risk), and Rizal, Palawan (high risk, control). Only one rapid diagnostic test (RDT)–positive infection and no PCR confirmed infections were found in Bataan and Occidental Mindoro, suggesting the absence of transmission. In Palawan, the inclusion of all health facility attendees, regardless of symptoms, and use of molecular diagnostics identified 313 infected individuals in addition to 300 cases identified by routine screening of febrile patients with the RDT or microscopy. Of these, the majority (313/613) were subpatent infections and only detected using molecular methods. Simultaneous collection of GPS coordinates on tablet-based applications allowed real-time mapping of malaria infections. Risk factor analysis showed higher risks in children and indigenous groups, with bed net use having a protective effect. Subpatent infections were more common in men and older age-groups. Overall, malaria risks were not associated with participants’ classification, and some of the non-patient clinic attendees reported febrile illnesses (1.9%, 26/1,369), despite not seeking treatment, highlighting the widespread distribution of infection in communities. Together, these data illustrate the utility of health facility–based surveys to augment surveillance data to increase the probability of detecting infections in the wider community.
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Affiliation(s)
- Ralph A Reyes
- 1Department of Parasitology, Research Institute for Tropical Medicine, Muntinlupa, Philippines
| | - Kimberly M Fornace
- 2Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | - Beaulah L Boncayao
- 1Department of Parasitology, Research Institute for Tropical Medicine, Muntinlupa, Philippines
| | - Ellaine S De La Fuente
- 1Department of Parasitology, Research Institute for Tropical Medicine, Muntinlupa, Philippines
| | - Hennessey M Sabanal
- 1Department of Parasitology, Research Institute for Tropical Medicine, Muntinlupa, Philippines
| | - Alison Paolo N Bareng
- 1Department of Parasitology, Research Institute for Tropical Medicine, Muntinlupa, Philippines
| | - Inez Andrea P Medado
- 3Molecular Biology Laboratory, Research Institute for Tropical Medicine, Muntinlupa, Philippines
| | - Edelwisa S Mercado
- 3Molecular Biology Laboratory, Research Institute for Tropical Medicine, Muntinlupa, Philippines
| | - Mario S Baquilod
- 4Department of Health, MIMAROPA Center for Health Development, Quirino Memorial Medical Center Compound, Quezon, Philippines
| | - Jennifer S Luchavez
- 1Department of Parasitology, Research Institute for Tropical Medicine, Muntinlupa, Philippines
| | - Julius Clemence R Hafalla
- 2Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Chris J Drakeley
- 2Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Fe Esperanza J Espino
- 1Department of Parasitology, Research Institute for Tropical Medicine, Muntinlupa, Philippines
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15
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Arinaitwe E, Nankabirwa JI, Krezanoski P, Rek J, Kamya V, Epstein A, Rosenthal PJ, Drakeley C, Kamya MR, Dorsey G, Staedke SG. Association between recent overnight travel and use of long-lasting insecticidal nets in rural Uganda: a prospective cohort study in Tororo. Malar J 2020; 19:405. [PMID: 33176793 PMCID: PMC7661187 DOI: 10.1186/s12936-020-03475-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 10/31/2020] [Indexed: 11/25/2022] Open
Abstract
Background The burden of malaria in Uganda remains high, but has become increasingly heterogenous following intensified malaria control. Travel within Uganda is recognized as a risk factor for malaria, but behaviours associated with travel are not well-understood. To address this knowledge gap, malaria-relevant behaviours of cohort participants were assessed during travel and at home in Uganda. Methods Residents from 80 randomly selected households in Nagongera sub-county, Tororo district were enrolled into a cohort to study malaria in rural Uganda. All participants were given long-lasting insecticidal nets (LLINs) at enrolment and were evaluated every 4 weeks at the study clinic. Participants were asked if they had travelled overnight from their home, and if so, a questionnaire was administered to capture information on travel details and behaviours. Behaviour while travelling was assessed within 4 weeks following travel during the study clinic visit. Behaviour while at home was assessed using a similar questionnaire during two-weekly home visits. Behaviours while travelling vs at home were compared using log binomial regression models with generalized estimating equations adjusting for repeated measures in the same individual. Analysis of factors associated with LLIN adherence, such as destination and duration of travel, time to bed during travel, gender and age at time of travel, were assessed using log binomial regression models with generalized estimating equations adjusting for repeated measures in the same individual. Results Between October 2017 and October 2019, 527 participants were enrolled and assessed for travel. Of these, 123 (23.2%) reported taking 211 overnight trips; 149 (70.6%) trips were within Tororo. Participants were less likely to use LLINs when travelling than when at home (41.0% vs. 56.2%, relative risk [RR] 0.73, 95% CI 0.60–0.89, p = 0.002); this difference was noted for women (38.8% vs 59.2%, RR 0.66, 95% CI 0.52–0.83, p = 0.001) but not men (48.3% vs 46.6%, RR 0.96, 95% CI 0.67–1.40, p = 0.85). In an adjusted analysis, factors associated with LLIN use when travelling included destination (travelling to districts not receiving indoor residual spraying [IRS] 65.8% vs Tororo district 32.2%, RR 1.80, 95% CI 1.31–2.46, p < 0.001) and duration of travel (> 7 nights 60.3% vs one night 24.4%, RR 1.97, 95% CI 1.07–3.64, p = 0.03). Conclusions Travellers, particularly women, were less likely to use LLINs when travelling than when at home. LLIN adherence was higher among those who travelled to non-IRS districts and for more than 1 week, suggesting that perceived malaria risk influences LLIN use. Strategies are needed to raise awareness of the importance of using LLINs while travelling.
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Affiliation(s)
- Emmanuel Arinaitwe
- London School of Hygiene and Tropical Medicine, London, UK. .,Infectious Diseases Research Collaboration, Kampala, Uganda.
| | - Joaniter I Nankabirwa
- Infectious Diseases Research Collaboration, Kampala, Uganda.,Department of Medicine, Makerere University, Kampala, Uganda
| | - Paul Krezanoski
- Department of Medicine, University of California, San Francisco, CA, USA
| | - John Rek
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Victor Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Adrienne Epstein
- Department of Medicine, University of California, San Francisco, CA, USA
| | - Philip J Rosenthal
- Department of Medicine, University of California, San Francisco, CA, USA
| | - Chris Drakeley
- London School of Hygiene and Tropical Medicine, London, UK
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda.,Department of Medicine, Makerere University, Kampala, Uganda
| | - Grant Dorsey
- Department of Medicine, University of California, San Francisco, CA, USA
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Targeting high risk forest goers for malaria elimination: a novel approach for investigating forest malaria to inform program intervention in Vietnam. BMC Infect Dis 2020; 20:757. [PMID: 33059623 PMCID: PMC7559775 DOI: 10.1186/s12879-020-05476-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 10/05/2020] [Indexed: 11/17/2022] Open
Abstract
Background Individuals that work and sleep in remote forest and farm locations in the Greater Mekong Subregion continue to remain at high risk of both acquiring and transmitting malaria. These difficult-to-access population groups largely fall outside the reach of traditional village-centered interventions, presenting operational challenges for malaria programs. In Vietnam, over 60% of malaria cases are thought to be individuals who sleep in forests or on farms. New malaria elimination strategies are needed in countries where mobile and migrant workers frequently sleep outside of their homes. The aim of this study was to apply targeted surveillance-response based investigative approaches to gather location-specific data on confirmed malaria cases, with an objective to identify associated malaria prevention, treatment and risk behaviors of individuals sleeping in remote forest and farms sites in Vietnam. Methods A cross-sectional study using novel targeted reactive investigative approaches at remote area sleeping sites was conducted in three mountainous communes in Phu Yen province in 2016. Index cases were defined as individuals routinely sleeping in forests or farms who had tested positive for malaria. Index cases and non-infected neighbors from forest and farm huts within 500 m of the established sleeping locations of index cases were interviewed at their remote-area sleeping sites. Results A total of 307 participants, 110 index cases and 197 neighbors, were enrolled. Among 93 participants who slept in the forest, index cases were more likely to make > 5 trips to the forest per year (prevalence odds ratio (POR) 7.41, 95% confidence interval (CI) 2.66–20.63), sleep in huts without walls (POR 44.00, 95% CI 13.05–148.33), sleep without mosquito nets (POR 2.95, 95% CI 1.26–6.92), and work after dark (POR 5.48, 95% CI 1.84–16.35). Of the 204 farm-based respondents, a significantly higher proportion of index cases were involved in non-farming activities (logging) (POR 2.74, 95% CI 1.27–5.91). Conclusion Investigative approaches employed in this study allowed for the effective recruitment and characterization of high-priority individuals frequently sleeping in remote forest and farm locations, providing relevant population and site-specific data that decision makers can use to design and implement targeted interventions to support malaria elimination.
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Ahmed S, Reithinger R, Kaptoge SK, Ngondi JM. Travel Is a Key Risk Factor for Malaria Transmission in Pre-Elimination Settings in Sub-Saharan Africa: A Review of the Literature and Meta-Analysis. Am J Trop Med Hyg 2020; 103:1380-1387. [PMID: 32815497 PMCID: PMC7543864 DOI: 10.4269/ajtmh.18-0456] [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] [Indexed: 12/03/2022] Open
Abstract
By sustaining transmission or causing malaria outbreaks, imported malaria undermines malaria elimination efforts. Few studies have examined the impact of travel on malaria epidemiology. We conducted a literature review and meta-analysis of studies investigating travel as a risk factor for malaria infection in sub-Saharan Africa using PubMed. We identified 22 studies and calculated a random-effects meta-analysis pooled odds ratio (OR) of 3.77 (95% CI: 2.49–5.70), indicating that travel is a significant risk factor for malaria infection. Odds ratios were particularly high in urban locations when travel was to rural areas, to more endemic/high transmission areas, and in young children. Although there was substantial heterogeneity in the magnitude of association across the studies, the pooled estimate and directional consistency support travel as an important risk factor for malaria infection.
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Affiliation(s)
- Sundus Ahmed
- Institute of Public Health, University of Cambridge, Cambridge, United Kingdom
| | | | - Stephen K Kaptoge
- Institute of Public Health, University of Cambridge, Cambridge, United Kingdom
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18
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Galatas B, Saúte F, Martí-Soler H, Guinovart C, Nhamussua L, Simone W, Munguambe H, Hamido C, Montañà J, Muguande O, Maartens F, Luis F, Paaijmans K, Mayor A, Bassat Q, Menéndez C, Macete E, Rabinovich R, Alonso PL, Candrinho B, Aide P. A multiphase program for malaria elimination in southern Mozambique (the Magude project): A before-after study. PLoS Med 2020; 17:e1003227. [PMID: 32797101 PMCID: PMC7428052 DOI: 10.1371/journal.pmed.1003227] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 07/17/2020] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Malaria eradication remains the long-term vision of the World Health Organization (WHO). However, whether malaria elimination is feasible in areas of stable transmission in sub-Saharan Africa with currently available tools remains a subject of debate. This study aimed to evaluate a multiphased malaria elimination project to interrupt Plasmodium falciparum malaria transmission in a rural district of southern Mozambique. METHODS AND FINDINGS A before-after study was conducted between 2015 and 2018 in the district of Magude, with 48,448 residents living in 10,965 households. Building on an enhanced surveillance system, two rounds of mass drug administrations (MDAs) per year over two years (phase I, August 2015-2017), followed by one year of reactive focal mass drug administrations (rfMDAs) (phase II, September 2017-June 2018) were deployed with annual indoor residual spraying (IRS), programmatically distributed long-lasting insecticidal nets (LLINs), and standard case management. The four MDA rounds covered 58%-72% of the population, and annual IRS reported coverage was >70%. Yearly parasite surveys and routine surveillance data were used to monitor the primary outcomes of the study-malaria prevalence and incidence-at baseline and annually since the onset of the project. Parasite prevalence by rapid diagnostic test (RDT) declined from 9.1% (95% confidence interval [CI] 7.0-11.8) in May 2015 to 2.6% (95% CI 2.0-3.4), representing a 71.3% (95% CI 71.1-71.4, p < 0.001) reduction after phase I, and to 1.4% (95% CI 0.9-2.2) after phase II. This represented an 84.7% (95% CI 81.4-87.4, p < 0.001) overall reduction in all-age prevalence. Case incidence fell from 195 to 75 cases per 1,000 during phase I (61.5% reduction) and to 67 per 1,000 during phase II (65.6% overall reduction). Interrupted time series (ITS) analysis was used to estimate the level and trend change in malaria cases associated with the set of project interventions and the number of cases averted. Phase I interventions were associated with a significant immediate reduction in cases of 69.1% (95% CI 57.5-77.6, p < 0.001). Phase II interventions were not associated with a level or trend change. An estimated 76.7% of expected cases were averted throughout the project (38,369 cases averted of 50,005 expected). One malaria-associated inpatient death was observed during the study period. There were 277 mild adverse events (AEs) recorded through the passive pharmacovigilance system during the four MDA rounds. One serious adverse event (SAE) that resulted in death was potentially related to the drug. The study was limited by the incomplete coverage of interventions, the quality of the routine and cross-sectional data collected, and the restricted accuracy of ITS analysis with a short pre-intervention period. CONCLUSION In this study, we observed that the interventions deployed during the Magude project fell short of interrupting P. falciparum transmission with the coverages achieved. While new tools and strategies may be required to eventually achieve malaria elimination in stable transmission areas of sub-Saharan Africa, this project showed that innovative mixes of interventions can achieve large reductions in disease burden, a necessary step in the pathway towards elimination. TRIAL REGISTRATION ClinicalTrials.gov NCT02914145.
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Affiliation(s)
- Beatriz Galatas
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique
- * E-mail:
| | - Francisco Saúte
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique
| | | | | | - Lidia Nhamussua
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique
| | - Wilson Simone
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique
| | | | - Camilo Hamido
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique
| | - Júlia Montañà
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique
| | - Olinda Muguande
- Fundação para o Desenvolvimento da Comunidade, Maputo, Mozambique
| | | | - Fabião Luis
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique
| | - Krijn Paaijmans
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique
- School of Life Sciences, Center for Evolution and Medicine, Biodesign Center for Immunotherapy, Vaccines and Virotherapy, Arizona State University, Tempe, United States of America
| | - Alfredo Mayor
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique
- CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Quique Bassat
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique
- CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
- ICREA, Pg. Lluís Companys 23, Barcelona, Spain
| | - Clara Menéndez
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique
- CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Eusebio Macete
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique
- National Institute of Health, Ministry of Health, Maputo, Mozambique
| | - Regina Rabinovich
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Pedro L. Alonso
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique
| | - Baltazar Candrinho
- National Malaria Control Program, Ministry of Health, Maputo, Mozambique
| | - Pedro Aide
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique
- National Institute of Health, Ministry of Health, Maputo, Mozambique
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19
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Ashton RA, Joseph V, van den Hoogen LL, Tetteh KKA, Stresman G, Worges M, Druetz T, Chang MA, Rogier E, Lemoine JF, Drakeley C, Eisele TP. Risk Factors for Malaria Infection and Seropositivity in the Elimination Area of Grand'Anse, Haiti: A Case-Control Study among Febrile Individuals Seeking Treatment at Public Health Facilities. Am J Trop Med Hyg 2020; 103:767-777. [PMID: 32458784 PMCID: PMC7410432 DOI: 10.4269/ajtmh.20-0097] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The island of Hispaniola aims to eliminate malaria by 2025; however, there are limited data to describe epidemiologic risk factors for malaria in this setting. A prospective case–control study was conducted at four health facilities in southwest Haiti, aiming to describe factors influencing the risk of current and past malaria infection. Cases were defined as individuals attending facilities with current or recent fever and positive malaria rapid diagnostic test (RDT), while controls were those with current or recent fever and RDT negative. Serological markers of recent and cumulative exposure to Plasmodium were assessed using the multiplex bead assay from dried blood spots and used for alternate case definitions. Kuldorff’s spatial scan statistic was used to identify local clusters of infection or exposure. Logistic regression models were used to assess potential risk factors for RDT positivity and recent exposure markers, including age-group, gender, and recruiting health facility as group-matching variables. A total of 192 cases (RDT positive) and 915 controls (RDT negative) were recruited. Consistent spatial clusters were identified for all three infection and exposure metrics, indicating temporal stability of malaria transmission at these sites. Risk factors included remoteness from health facilities and household construction, furthermore, insecticide-treated net ownership or use was associated with reduced odds of RDT positivity. These findings indicate the malaria risk in Grand’Anse is driven primarily by location. Travel, occupation, and other behavioral factors were not associated with malaria. These data can support the National Malaria Program to refine and target their intervention approaches, and to move toward elimination.
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Affiliation(s)
- Ruth A Ashton
- Center for Applied Malaria Research and Evaluation, Tulane School of Public Health and Tropical Medicine, New Orleans, Louisiana
| | - Vena Joseph
- Center for Applied Malaria Research and Evaluation, Tulane School of Public Health and Tropical Medicine, New Orleans, Louisiana
| | - Lotus L van den Hoogen
- Center for Applied Malaria Research and Evaluation, Tulane School of Public Health and Tropical Medicine, New Orleans, Louisiana
| | - Kevin K A Tetteh
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Gillian Stresman
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Matt Worges
- Center for Applied Malaria Research and Evaluation, Tulane School of Public Health and Tropical Medicine, New Orleans, Louisiana
| | - Thomas Druetz
- Department of Social and Preventive Medicine, University of Montreal School of Public Health, Montreal, Canada.,Center for Applied Malaria Research and Evaluation, Tulane School of Public Health and Tropical Medicine, New Orleans, Louisiana
| | - Michelle A Chang
- Division of Parasitic Diseases and Malaria, Malaria Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Eric Rogier
- Division of Parasitic Diseases and Malaria, Malaria Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Jean Frantz Lemoine
- Programme National de Contrôle de la Malaria, Ministry of Public Health and Population, Port-au-Prince, Haiti
| | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Thomas P Eisele
- Center for Applied Malaria Research and Evaluation, Tulane School of Public Health and Tropical Medicine, New Orleans, Louisiana
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20
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Chanda E, Arshad M, Khaloua A, Zhang W, Namboze J, Uusiku P, Angula AH, Gausi K, Tiruneh D, Islam QM, Kolivras K, Haque U. An investigation of the Plasmodium falciparum malaria epidemic in Kavango and Zambezi regions of Namibia in 2016. Trans R Soc Trop Med Hyg 2019; 112:546-554. [PMID: 30252108 DOI: 10.1093/trstmh/try097] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 08/10/2018] [Indexed: 01/26/2023] Open
Abstract
Background Namibia is one of the countries among the eight that are targeting malaria elimination in southern Africa. However, the country has encountered malaria epidemics in recent years. The objective of this study was to investigate malaria epidemics and to contribute to strengthening malaria surveillance and control in an effort to move Namibia toward eliminating malaria. Method Malaria epidemiology data for 2014-2015 were collected from the weekly surveillance system. All consenting household members within a 100-m radius of index households were screened in 2016 using a Carestart malaria HRP2/pLDH combined rapid diagnostic test after epidemics. All houses within this radius were sprayed in 2016 with the pyrethroid deltamethrin and K-Othrine WG 250. Anopheles mosquito-positive breeding sites were identified and treated with the organophosphate larvicide temephos. Insecticide susceptibility and bioassay tests were conducted. Results During the epidemic response period in 2016, 56 parasitologically confirmed Plasmodium falciparum malaria cases in the Zambezi region were detected from active screening. The majority of those cases (83%) were asymptomatic infections. In the Kavango region, the malaria epidemic persisted, with 228 P. falciparum malaria cases recorded, but only 97 were investigated. In Namibia, malaria vector susceptibility was detected to 4% dichlorodiphenyltrichloroethane. Indoor residual spraying was conducted in 377 (90%) of the targeted households along with community awareness through health education of 1499 people and distribution of more than 2000 information, education and communication materials. The P. falciparum malaria cases in the Zambezi decreased from 122 in week 9 to 97 after week 15. Conclusions Malaria epidemics along with the persistence of asymptomatic reservoir infections pose a serious challenge in Namibia's elimination effort. The country needs to ensure sustainable interventions to target asymptomatic reservoir infections and prevent epidemics in order to successfully achieve its goal of eliminating malaria.
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Affiliation(s)
- Emmanuel Chanda
- World Health Organization, Regional Office for Africa, Cite du Djoue, Brazzaville, Republic of the Congo
| | - Mohd Arshad
- Department of Statistics and Operations Research, Aligarh Muslim University, Aligarh, India
| | - Asmaa Khaloua
- Department of Computer Science and Engineering, 1155 Union Circle #311366 Denton, Texas, USA
| | - Wenyi Zhang
- Institute of Disease Control and Prevention of PLA, NO. 20 Dong-Da-Jie Street, Fengtai District, Beijing, PR China
| | - Josephine Namboze
- World Health Organization, Country Office, Geza Banda-Adi Yacob St 178, Asmara 291-1, Eritrea
| | - Pentrina Uusiku
- Ministry of Health and Social Services, National Vector-borne Diseases Control Programme, Florence Nightingale Street, Windhoek, Namibia
| | - Andreas H Angula
- Ministry of Health and Social Services, National Vector-borne Diseases Control Programme, Florence Nightingale Street, Windhoek, Namibia
| | - Khoti Gausi
- World Health Organization, East and Southern Africa Inter-country Support Team, Causeway Harare, Zimbabwe
| | - Desta Tiruneh
- World Health Organization, Country Office, Windhoek, Namibia
| | - Quazi M Islam
- World Health Organization, Country Office, Windhoek, Namibia
| | - Korine Kolivras
- Department of Geography, Virginia Tech, 220 Stanger St, 115 Major Williams Hall, Blacksburg, VA, USA
| | - Ubydul Haque
- Department of Geography, University of Florida, Gainesville, FL, USA.,Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA.,Department of Biostatistics and Epidemiology, University of North Texas Health Science Center, Fort Worth, TX
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21
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Monroe A, Mihayo K, Okumu F, Finda M, Moore S, Koenker H, Lynch M, Haji K, Abbas F, Ali A, Greer G, Harvey S. Human behaviour and residual malaria transmission in Zanzibar: findings from in-depth interviews and direct observation of community events. Malar J 2019; 18:220. [PMID: 31262306 PMCID: PMC6604484 DOI: 10.1186/s12936-019-2855-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 06/25/2019] [Indexed: 11/24/2022] Open
Abstract
Background Zanzibar has maintained malaria prevalence below 1% for the past decade, yet elimination remains elusive despite high coverage of core vector control interventions. As part of a study investigating the magnitude and drivers of residual transmission in Zanzibar, qualitative methods were utilized to better understand night time activities and sleeping patterns, individual and community-level risk perceptions, and malaria prevention practices. Methods A total of 62 in-depth interviews were conducted with community members and local leaders across six sites on Unguja Island, Zanzibar. Twenty semi-structured community observations of night-time activities and special events were conducted to complement interview findings. Data were transcribed verbatim, coded, and analysed using a thematic approach. Results Participants reported high levels of ITN use, but noted gaps in protection, particularly when outdoors or away from home. Routine household and community activities were common in evenings before bed and early mornings, while livelihood activities and special events lasted all or most of the night. Gender variation was reported, with men routinely spending more time away from home than women and children. Outdoor sleeping was reported during special events, such as weddings, funerals, and religious ceremonies. Participants described having difficulty preventing mosquito bites while outdoors, travelling, or away from home, and perceived higher risk of malaria infection during these times. Travel and migration emerged as a crucial issue and participants viewed seasonal workers coming from mainland Tanzania as more likely to have a malaria infection and less likely to be connected to prevention and treatment services in Zanzibar. Some community leaders reported taking the initiative to register seasonal workers coming into their community and linking them to testing and treatment services. Conclusions Targeting malaria interventions effectively is critical and should be informed by a clear understanding of relevant human behaviour. These findings highlight malaria prevention gaps in Zanzibar, and the importance of identifying new approaches to complement current interventions and accelerate the final phases of malaria elimination. Development and deployment of complementary interventions should consider human behaviour, including gender norms, that can influence exposure to malaria vectors and prevention practices. Expansion of community-level programmes targeting travellers and seasonal workers should also be explored.
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Affiliation(s)
- April Monroe
- PMI VectorWorks Project, Johns Hopkins Center for Communication Programs, Baltimore, MD, USA. .,University of Basel, Basel, Switzerland. .,Swiss Tropical and Public Health Institute, Basel, Switzerland.
| | - Kimberly Mihayo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Fredros Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania.,School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Parktown, Republic of South Africa.,Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Marceline Finda
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Sarah Moore
- University of Basel, Basel, Switzerland.,Swiss Tropical and Public Health Institute, Basel, Switzerland.,Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Hannah Koenker
- PMI VectorWorks Project, Johns Hopkins Center for Communication Programs, Baltimore, MD, USA
| | - Matthew Lynch
- PMI VectorWorks Project, Johns Hopkins Center for Communication Programs, Baltimore, MD, USA
| | - Khamis Haji
- Zanzibar Malaria Elimination Programme, Zanzibar, Tanzania
| | - Faiza Abbas
- Zanzibar Malaria Elimination Programme, Zanzibar, Tanzania
| | - Abdullah Ali
- Zanzibar Malaria Elimination Programme, Zanzibar, Tanzania
| | - George Greer
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Dar Es Salaam, Tanzania
| | - Steven Harvey
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
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22
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Jacobson JO, Smith JL, Cueto C, Chisenga M, Roberts K, Hsiang M, Gosling R, Mumbengegwi D, Bennett A. Assessing malaria risk at night-time venues in a low-transmission setting: a time-location sampling study in Zambezi, Namibia. Malar J 2019; 18:179. [PMID: 31118028 PMCID: PMC6532237 DOI: 10.1186/s12936-019-2807-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 05/10/2019] [Indexed: 12/20/2022] Open
Abstract
Background Identifying efficient and effective strategies to reach and monitor populations at greatest risk of malaria in low-transmission settings is a key challenge for malaria elimination. In Namibia’s Zambezi Region, transmission is ongoing yet its drivers remain poorly understood. A growing literature suggests that night-time social activities may lead to malaria exposure that is beyond the reach of conventional preventive interventions, such as insecticide treated bed nets and indoor residual spraying. Methods Formative research was conducted with community members in March, 2015 in the catchment areas of six randomly selected health facilities in the western Zambezi Region to identify night-time locations where large numbers of individuals regularly congregate. Using time-location sampling, a survey was conducted between March and May, 2015 at community-identified venues (bars and evening church services) to develop representative estimates of the prevalence of parasite infection and risk factors among venue-goers. Results When compared to a contemporaneous household survey of the general population aged 15 and older (N = 1160), venue-goers (N = 480) were more likely to have spent the night away from their home recently (17.3% vs. 8.9%, P = 0.008), report recent fever (65.2% vs. 36.9%, P < 0.001), and were less likely to have sought care for fever (37.9% vs. 52.1%, P = 0.011). Venue-goers had higher, but not significantly different, rates of malaria infection (4.7% vs. 2.8%, P = 0.740). Risk factors for malaria infection among venue-goers could not be determined due to the small number of infections identified, however self-reported fever was positively associated with outdoor livelihood activities (adjusted odds ratio [AOR] = 1.9, 95% CI 1.0–3.3), not wearing protective measures at the time of the survey (AOR = 6.8, 9% CI 1.4–33.6) and having been bothered by mosquitos at the venue (AOR = 2.7, 95% CI 1.5–4). Conclusions Prevention measures and continued surveillance at night-time venues may be a useful complement to existing malaria elimination efforts.
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Affiliation(s)
- Jerry O Jacobson
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, 550 16th St., San Francisco, CA, 94158, USA
| | - Jennifer L Smith
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, 550 16th St., San Francisco, CA, 94158, USA
| | - Carmen Cueto
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, 550 16th St., San Francisco, CA, 94158, USA
| | - Mukosha Chisenga
- Multidisciplinary Research Center, University of Namibia, Windhoek, Namibia
| | - Kathryn Roberts
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, 550 16th St., San Francisco, CA, 94158, USA
| | - Michelle Hsiang
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, 550 16th St., San Francisco, CA, 94158, USA.,Department of Pediatrics, Benioff Children's Hospital, University of California San Francisco, San Francisco, CA, USA.,Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Roly Gosling
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, 550 16th St., San Francisco, CA, 94158, USA
| | - Davis Mumbengegwi
- Multidisciplinary Research Center, University of Namibia, Windhoek, Namibia
| | - Adam Bennett
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, 550 16th St., San Francisco, CA, 94158, USA.
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23
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Tessema S, Wesolowski A, Chen A, Murphy M, Wilheim J, Mupiri AR, Ruktanonchai NW, Alegana VA, Tatem AJ, Tambo M, Didier B, Cohen JM, Bennett A, Sturrock HJW, Gosling R, Hsiang MS, Smith DL, Mumbengegwi DR, Smith JL, Greenhouse B. Using parasite genetic and human mobility data to infer local and cross-border malaria connectivity in Southern Africa. eLife 2019; 8:e43510. [PMID: 30938286 PMCID: PMC6478435 DOI: 10.7554/elife.43510] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 03/06/2019] [Indexed: 02/04/2023] Open
Abstract
Local and cross-border importation remain major challenges to malaria elimination and are difficult to measure using traditional surveillance data. To address this challenge, we systematically collected parasite genetic data and travel history from thousands of malaria cases across northeastern Namibia and estimated human mobility from mobile phone data. We observed strong fine-scale spatial structure in local parasite populations, providing positive evidence that the majority of cases were due to local transmission. This result was largely consistent with estimates from mobile phone and travel history data. However, genetic data identified more detailed and extensive evidence of parasite connectivity over hundreds of kilometers than the other data, within Namibia and across the Angolan and Zambian borders. Our results provide a framework for incorporating genetic data into malaria surveillance and provide evidence that both strengthening of local interventions and regional coordination are likely necessary to eliminate malaria in this region of Southern Africa.
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Affiliation(s)
- Sofonias Tessema
- EPPIcenter program, Division of HIV, Infectious Diseases and Global Medicine, Department of MedicineUniversity of California, San FranciscoSan FranciscoUnited States
| | - Amy Wesolowski
- Department of EpidemiologyJohns Hopkins Bloomberg School of Public HealthBaltimoreUnited States
| | - Anna Chen
- EPPIcenter program, Division of HIV, Infectious Diseases and Global Medicine, Department of MedicineUniversity of California, San FranciscoSan FranciscoUnited States
| | - Maxwell Murphy
- EPPIcenter program, Division of HIV, Infectious Diseases and Global Medicine, Department of MedicineUniversity of California, San FranciscoSan FranciscoUnited States
| | - Jordan Wilheim
- EPPIcenter program, Division of HIV, Infectious Diseases and Global Medicine, Department of MedicineUniversity of California, San FranciscoSan FranciscoUnited States
| | - Anna-Rosa Mupiri
- Multidisciplinary Research CenterUniversity of NamibiaWindhoekNamibia
| | - Nick W Ruktanonchai
- WorldPop Project, Geography and EnvironmentUniversity of SouthamptonSouthamptonUnited Kingdom
| | - Victor A Alegana
- Multidisciplinary Research CenterUniversity of NamibiaWindhoekNamibia
- WorldPop Project, Geography and EnvironmentUniversity of SouthamptonSouthamptonUnited Kingdom
| | - Andrew J Tatem
- WorldPop Project, Geography and EnvironmentUniversity of SouthamptonSouthamptonUnited Kingdom
| | - Munyaradzi Tambo
- Multidisciplinary Research CenterUniversity of NamibiaWindhoekNamibia
| | | | | | - Adam Bennett
- Malaria Elimination Initiative, Institute of Global Health SciencesUniversity of California, San FranciscoSan FranciscoUnited States
| | - Hugh JW Sturrock
- Malaria Elimination Initiative, Institute of Global Health SciencesUniversity of California, San FranciscoSan FranciscoUnited States
| | - Roland Gosling
- Multidisciplinary Research CenterUniversity of NamibiaWindhoekNamibia
- Malaria Elimination Initiative, Institute of Global Health SciencesUniversity of California, San FranciscoSan FranciscoUnited States
| | - Michelle S Hsiang
- Malaria Elimination Initiative, Institute of Global Health SciencesUniversity of California, San FranciscoSan FranciscoUnited States
- Department of PediatricsUniversity of Texas Southwestern Medical CenterDallasUnited States
- Department of PediatricsUCSF Benioff Children's HospitalSan FranciscoUnited States
| | - David L Smith
- Institute for Health Metrics and EvaluationUniversity of WashingtonSeattleUnited States
| | | | - Jennifer L Smith
- Malaria Elimination Initiative, Institute of Global Health SciencesUniversity of California, San FranciscoSan FranciscoUnited States
| | - Bryan Greenhouse
- EPPIcenter program, Division of HIV, Infectious Diseases and Global Medicine, Department of MedicineUniversity of California, San FranciscoSan FranciscoUnited States
- Chan Zuckerberg BiohubSan FranciscoUnited States
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24
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Mohammed-Awel J, Gumel AB. Mathematics of an epidemiology-genetics model for assessing the role of insecticides resistance on malaria transmission dynamics. Math Biosci 2019; 312:33-49. [PMID: 30825481 DOI: 10.1016/j.mbs.2019.02.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 02/05/2019] [Accepted: 02/24/2019] [Indexed: 12/11/2022]
Abstract
Although the widespread use of indoors residual spraying (IRS) and insecticides treated bednets (ITNs; later replaced by long-lasting insecticidal nets (LLINs)) has led to a dramatic reduction of malaria burden in endemic areas, such usage has also resulted in the major challenge of the evolution of insecticide resistance in the mosquito population in those areas. Thus, efforts to combat malaria also include the urgent problem of effectively managing insecticide resistance. This study is based on the design and analysis of a new mathematical model for assessing the impact of insecticides resistance in the mosquito population (due to widespread use of IRS and ITNs) on the transmission dynamics and control of malaria in a community. The model, which couples disease epidemiology with vector population genetics, incorporates several fitness costs associated with insecticide resistance. Detailed rigorous analysis of the model is presented. Using data and parameter values relevant to malaria dynamics in moderate and high malaria transmission settings in some parts of Ethiopia, simulations of the model show that, while the ITNs-IRS strategy can lead to the effective control of the disease in both the moderate and high malaria transmission setting if the ITNs coverage level in the community is high enough (regardless of the level of IRS coverage), it fails to manage insecticide resistance (as measured in terms of the frequency of resistant allele at equilibrium in the community). It is further shown that the effective size of the coverage level of the ITNs and IRS required to effectively control the disease, while effectively managing insecticide resistance in the mosquito population, depends on the magnitude of the level of resistant allele dominance (in mosquitoes with heterozygous genotype) and several fitness costs associated with the insecticide resistance in the vector population. For instance, in a moderate transmission setting, malaria burden can be reduced to low levels of endemicity (even with low coverage of ITNs and IRS), and insecticide resistance effectively managed, if the fitness costs of resistance are at their assumed baseline values. Such reduction is not achievable if the fitness costs of resistance are lower than the baseline values.
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Affiliation(s)
- Jemal Mohammed-Awel
- Department of Mathematics, Valdosta State University, Valdosta, Ga 31698, USA.
| | - Abba B Gumel
- School of Mathematical and Statistical Sciences, Arizona State University, Tempe, AZ, 85287, USA; Department of Mathematics and Applied Mathematics, University of Pretoria, Pretoria 0002, South Africa
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Carrasco-Escobar G, Castro MC, Barboza JL, Ruiz-Cabrejos J, Llanos-Cuentas A, Vinetz JM, Gamboa D. Use of open mobile mapping tool to assess human mobility traceability in rural offline populations with contrasting malaria dynamics. PeerJ 2019; 7:e6298. [PMID: 30697487 PMCID: PMC6346981 DOI: 10.7717/peerj.6298] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 12/18/2018] [Indexed: 11/20/2022] Open
Abstract
Infectious disease dynamics are affected by human mobility more powerfully than previously thought, and thus reliable traceability data are essential. In rural riverine settings, lack of infrastructure and dense tree coverage deter the implementation of cutting-edge technology to collect human mobility data. To overcome this challenge, this study proposed the use of a novel open mobile mapping tool, GeoODK. This study consists of a purposive sampling of 33 participants in six villages with contrasting patterns of malaria transmission that demonstrates a feasible approach to map human mobility. The self-reported traceability data allowed the construction of the first human mobility framework in rural riverine villages in the Peruvian Amazon. The mobility spectrum in these areas resulted in travel profiles ranging from 2 hours to 19 days; and distances between 10 to 167 km. Most Importantly, occupational-related mobility profiles with the highest displacements (in terms of time and distance) were observed in commercial, logging, and hunting activities. These data are consistent with malaria transmission studies in the area that show villages in watersheds with higher human movement are concurrently those with greater malaria risk. The approach we describe represents a potential tool to gather critical information that can facilitate malaria control activities.
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Affiliation(s)
- Gabriel Carrasco-Escobar
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru.,Division of Infectious Diseases, Department of Medicine, University of California, San Diego, La Jolla, CA, United States of America
| | - Marcia C Castro
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA, United States of America
| | - Jose Luis Barboza
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Jorge Ruiz-Cabrejos
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Alejandro Llanos-Cuentas
- Instituto de Medicinal Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Joseph M Vinetz
- Instituto de Medicinal Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru.,Department of Infectious diseases, School of Medicine, Yale University, New Haven, CT, United States of America
| | - Dionicia Gamboa
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru.,Instituto de Medicinal Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru.,Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
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26
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McCreesh P, Mumbengegwi D, Roberts K, Tambo M, Smith J, Whittemore B, Kelly G, Moe C, Murphy M, Chisenga M, Greenhouse B, Ntuku H, Kleinschmidt I, Sturrock H, Uusiku P, Gosling R, Bennett A, Hsiang MS. Subpatent malaria in a low transmission African setting: a cross-sectional study using rapid diagnostic testing (RDT) and loop-mediated isothermal amplification (LAMP) from Zambezi region, Namibia. Malar J 2018; 17:480. [PMID: 30567537 PMCID: PMC6299963 DOI: 10.1186/s12936-018-2626-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 12/11/2018] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Subpatent malaria infections, or low-density infections below the detection threshold of microscopy or standard rapid diagnostic testing (RDT), can perpetuate persistent transmission and, therefore, may be a barrier for countries like Namibia that are pursuing malaria elimination. This potential burden in Namibia has not been well characterized. METHODS Using a two-stage cluster sampling, cross-sectional design, subjects of all age were enrolled during the end of the 2015 malaria transmission season in Zambezi region, located in northeast Namibia. Malaria RDTs were performed with subsequent gold standard testing by loop-mediated isothermal amplification (LAMP) using dried blood spots. Infection prevalence was measured and the diagnostic accuracy of RDT calculated. Relationships between recent fever, demographics, epidemiological factors, and infection were assessed. RESULTS Prevalence of Plasmodium falciparum malaria infection was low: 0.8% (16/1919) by RDT and 2.2% (43/1919) by LAMP. All but one LAMP-positive infection was RDT-negative. Using LAMP as gold standard, the sensitivity and specificity of RDT were 2.3% and 99.2%, respectively. Compared to LAMP-negative infections, a higher portion LAMP-positive infections were associated with fever (45.2% vs. 30.4%, p = 0.04), though 55% of infections were not associated with fever. Agricultural occupations and cattle herding were significantly associated with LAMP-detectable infection (Adjusted ORs 5.02, 95% CI 1.77-14.23, and 11.82, 95% CI 1.06-131.81, respectively), while gender, travel, bed net use, and indoor residual spray coverage were not. CONCLUSIONS This study presents results from the first large-scale malaria cross-sectional survey from Namibia using molecular testing to characterize subpatent infections. Findings suggest that fever history and standard RDTs are not useful to address this burden. Achievement of malaria elimination may require active case detection using more sensitive point-of-care diagnostics or presumptive treatment and targeted to high-risk groups.
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Affiliation(s)
- Patrick McCreesh
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA.,Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Davis Mumbengegwi
- Multidisciplinary Research Center, University of Namibia, Windhoek, Namibia
| | - Kathryn Roberts
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Munyaradzi Tambo
- Multidisciplinary Research Center, University of Namibia, Windhoek, Namibia
| | - Jennifer Smith
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Brooke Whittemore
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Gerard Kelly
- Burnet Institute for Medical Research and Public Health, Melbourne, Australia
| | - Caitlin Moe
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Max Murphy
- Division of HIV, Infectious Diseases and Global Medicine, Department of Medicine, UCSF, San Francisco, CA, USA
| | - Mukosha Chisenga
- Multidisciplinary Research Center, University of Namibia, Windhoek, Namibia
| | - Bryan Greenhouse
- Division of HIV, Infectious Diseases and Global Medicine, Department of Medicine, UCSF, San Francisco, CA, USA
| | - Henry Ntuku
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Immo Kleinschmidt
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK.,Wits Research Institute for Malaria, University of Witwatersrands, Johannesburg, South Africa
| | - Hugh Sturrock
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Petrina Uusiku
- National Vectorborne Disease Control Programme, Namibia Ministry of Health and Social Services, Windhoek, Namibia
| | - Roland Gosling
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Adam Bennett
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Michelle S Hsiang
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco (UCSF), San Francisco, CA, USA. .,Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA. .,Department of Pediatrics, UCSF Benioff Children's Hospital, San Francisco, CA, USA.
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27
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Khadka A, Perales NA, Wei DJ, Gage AD, Haber N, Verguet S, Patenaude B, Fink G. Malaria control across borders: quasi-experimental evidence from the Trans-Kunene malaria initiative (TKMI). Malar J 2018; 17:224. [PMID: 29866113 PMCID: PMC5987525 DOI: 10.1186/s12936-018-2368-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 05/25/2018] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND The transmission of malaria through population inflows from highly endemic areas with limited control efforts poses major challenges for national malaria control programmes. Several multilateral programmes have been launched in recent years to address cross-border transmission. This study assesses the potential impact of such a programme at the Angolan-Namibian border. METHODS Community-based malaria prevention programmes involving bed net distribution and behaviour change home visits were rolled-out using a controlled, staggered (stepped wedge) design between May 2014 and July 2016 in a 100 × 40 km corridor along the Angolan-Namibian border. Three rounds of survey data were collected. The primary outcome studied was fever among children under five in the 2 weeks prior to the survey. Multivariable linear and logistic regression models were used to assess overall programme impact and the relative impact of unilateral versus coordinated bilateral intervention programmes. RESULTS A total of 3844 child records were analysed. On average, programme rollout reduced the odds of child fever by 54% (aOR: 0.46, 95% CI 0.29 to 0.73) over the intervention period. In Namibia, the programme reduced the odds of fever by 30% in areas without simultaneous Angolan efforts (aOR: 0.70, 95% CI 0.34 to 1.44), and by an additional 62% in areas with simultaneous Angolan programmes. In Angola, the programme was highly effective in areas within 5 km of Namibian programmes (OR: 0.37, 95% CI 0.22 to 0.62), but mostly ineffective in areas closer to inland Angolan areas without concurrent anti-malarial efforts. CONCLUSIONS The impact of malaria programmes depends on programme efforts in surrounding areas with differential control efforts. Coordinated malaria programming within and across countries will be critical for achieving the vision of a malaria free world.
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Affiliation(s)
- Aayush Khadka
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, 655 Huntington Avenue, Boston, MA, 02115, USA.
| | | | - Dorothy J Wei
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, 655 Huntington Avenue, Boston, MA, 02115, USA
| | - Anna D Gage
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, 655 Huntington Avenue, Boston, MA, 02115, USA
| | - Noah Haber
- Carolina Population Center, University of North Carolina, Chapel Hill, NC, 27516, USA
| | - Stéphane Verguet
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, 655 Huntington Avenue, Boston, MA, 02115, USA
| | - Bryan Patenaude
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, 655 Huntington Avenue, Boston, MA, 02115, USA
| | - Günther Fink
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, 655 Huntington Avenue, Boston, MA, 02115, USA
- Swiss Tropical and Public Health Institute and University of Basel, Basel, Switzerland
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28
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Strano E, Viana MP, Sorichetta A, Tatem AJ. Mapping road network communities for guiding disease surveillance and control strategies. Sci Rep 2018; 8:4744. [PMID: 29549364 PMCID: PMC5856805 DOI: 10.1038/s41598-018-22969-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 02/26/2018] [Indexed: 01/19/2023] Open
Abstract
Human mobility is increasing in its volume, speed and reach, leading to the movement and introduction of pathogens through infected travelers. An understanding of how areas are connected, the strength of these connections and how this translates into disease spread is valuable for planning surveillance and designing control and elimination strategies. While analyses have been undertaken to identify and map connectivity in global air, shipping and migration networks, such analyses have yet to be undertaken on the road networks that carry the vast majority of travellers in low and middle income settings. Here we present methods for identifying road connectivity communities, as well as mapping bridge areas between communities and key linkage routes. We apply these to Africa, and show how many highly-connected communities straddle national borders and when integrating malaria prevalence and population data as an example, the communities change, highlighting regions most strongly connected to areas of high burden. The approaches and results presented provide a flexible tool for supporting the design of disease surveillance and control strategies through mapping areas of high connectivity that form coherent units of intervention and key link routes between communities for targeting surveillance.
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Affiliation(s)
- Emanuele Strano
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA, 02139, USA.
- German Aerospace Center (DLR), German Remote Sensing Data Center (DFD), Oberpfaffenhofen, D-82234, Wessling, Germany.
| | | | - Alessandro Sorichetta
- WorldPop, Department of Geography and Environment, University of Southampton, Highfield, Southampton, UK
- Flowminder Foundation, Stockholm, Sweden
| | - Andrew J Tatem
- WorldPop, Department of Geography and Environment, University of Southampton, Highfield, Southampton, UK.
- Flowminder Foundation, Stockholm, Sweden.
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29
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Medzihradsky OF, Kleinschmidt I, Mumbengegwi D, Roberts KW, McCreesh P, Dufour MSK, Uusiku P, Katokele S, Bennett A, Smith J, Sturrock H, Prach LM, Ntuku H, Tambo M, Didier B, Greenhouse B, Gani Z, Aerts A, Gosling R, Hsiang MS. Study protocol for a cluster randomised controlled factorial design trial to assess the effectiveness and feasibility of reactive focal mass drug administration and vector control to reduce malaria transmission in the low endemic setting of Namibia. BMJ Open 2018; 8:e019294. [PMID: 29374672 PMCID: PMC5829876 DOI: 10.1136/bmjopen-2017-019294] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
INTRODUCTION To interrupt malaria transmission, strategies must target the parasite reservoir in both humans and mosquitos. Testing of community members linked to an index case, termed reactive case detection (RACD), is commonly implemented in low transmission areas, though its impact may be limited by the sensitivity of current diagnostics. Indoor residual spraying (IRS) before malaria season is a cornerstone of vector control efforts. Despite their implementation in Namibia, a country approaching elimination, these methods have been met with recent plateaus in transmission reduction. This study evaluates the effectiveness and feasibility of two new targeted strategies, reactive focal mass drug administration (rfMDA) and reactive focal vector control (RAVC) in Namibia. METHODS AND ANALYSIS This is an open-label cluster randomised controlled trial with 2×2 factorial design. The interventions include: rfMDA (presumptive treatment with artemether-lumefantrine (AL)) versus RACD (rapid diagnostic testing and treatment using AL) and RAVC (IRS with Acellic 300CS) versus no RAVC. Factorial design also enables comparison of the combined rfMDA+RAVC intervention to RACD. Participants living in 56 enumeration areas will be randomised to one of four arms: rfMDA, rfMDA+RAVC, RACD or RACD+RAVC. These interventions, triggered by index cases detected at health facilities, will be targeted to individuals residing within 500 m of an index. The primary outcome is cumulative incidence of locally acquired malaria detected at health facilities over 1 year. Secondary outcomes include seroprevalence, infection prevalence, intervention coverage, safety, acceptability, adherence, cost and cost-effectiveness. ETHICS AND DISSEMINATION Findings will be reported on clinicaltrials.gov, in peer-reviewed publications and through stakeholder meetings with MoHSS and community leaders in Namibia. TRIAL REGISTRATION NUMBER NCT02610400; Pre-results.
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Affiliation(s)
- Oliver F Medzihradsky
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, California, USA
- Department of Pediatrics, Benioff Children's Hospital, University of California San Francisco, San Francisco, California, USA
| | - Immo Kleinschmidt
- Department of Infectious Disease Epidemiology, The London School of Hygiene and Tropical Medicine, London, UK
- Faculty of Health Sciences, School of Pathology, University of Witwatersrand, Johannesburg, South Africa
| | - Davis Mumbengegwi
- Multidisciplinary Research Centre, University of Namibia, Windhoek, Namibia
| | - Kathryn W Roberts
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, California, USA
| | - Patrick McCreesh
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Mi-Suk Kang Dufour
- Division of Prevention Science, University of California San Francisco, San Francisco, California, USA
| | - Petrina Uusiku
- National Vector-borne Diseases Control Programme, Ministry of Health and Social Services, Windhoek, Namibia
| | - Stark Katokele
- National Vector-borne Diseases Control Programme, Ministry of Health and Social Services, Windhoek, Namibia
| | - Adam Bennett
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, California, USA
| | - Jennifer Smith
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, California, USA
| | - Hugh Sturrock
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, California, USA
| | - Lisa M Prach
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, California, USA
| | - Henry Ntuku
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, California, USA
| | - Munyaradzi Tambo
- Faculty of Health Sciences, School of Pathology, University of Witwatersrand, Johannesburg, South Africa
| | - Bradley Didier
- Clinton Health Access Initiative, Boston, Massachusetts, USA
| | - Bryan Greenhouse
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, USA
| | | | - Ann Aerts
- Novartis Foundation, Basel, Switzerland
| | - Roly Gosling
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, California, USA
| | - Michelle S Hsiang
- Malaria Elimination Initiative, Global Health Group, University of California San Francisco, San Francisco, California, USA
- Department of Pediatrics, Benioff Children's Hospital, University of California San Francisco, San Francisco, California, USA
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Spatial clustering of patent and sub-patent malaria infections in northern Namibia: Implications for surveillance and response strategies for elimination. PLoS One 2017; 12:e0180845. [PMID: 28820883 PMCID: PMC5562317 DOI: 10.1371/journal.pone.0180845] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 06/22/2017] [Indexed: 11/25/2022] Open
Abstract
Background Reactive case detection (RACD) around passively detected malaria cases is a strategy to identify and treat hotspots of malaria transmission. This study investigated the unproven assumption on which this approach is based, that in low transmission settings, infections cluster over small scales. Methods A prospective case-control study was conducted between January 2013 and August 2014 in Ohangwena and Omusati regions in north central Namibia. Patients attending health facilities who tested positive by malaria rapid diagnostic test (RDT) (index cases) were traced back to their home. All occupants of index case households (n = 116 households) and surrounding households (n = 225) were screened for Plasmodium infection with a rapid diagnostic test (RDT) and loop mediated isothermal amplification (LAMP) and interviewed to identify risk factors. A comparison group of 286 randomly-selected control households was also screened, to compare infection levels of RACD and non-RACD households and their neighbours. Logistic regression was used to investigate spatial clustering of patent and sub-patent infections around index cases and to identify potential risk factors that would inform screening approaches and identify risk groups. Estimates of the impact of RACD on onward transmission to mosquitoes was made using previously published figures of infection rates. Results Prevalence of Plasmodium falciparum infection by LAMP was 3.4%, 1.4% and 0.4% in index-case households, neighbors of index case households and control households respectively; adjusted odds ratio 6.1 [95%CI 1.9–19.5] comparing case households versus control households. Using data from Engela, neighbors of cases had higher odds of infection [adjusted OR 5.0 95%CI 1.3–18.9] compared to control households. All infections identified by RDTs were afebrile and RDTs identified only a small proportion of infections in case (n = 7; 17%) and control (0%) neighborhoods. Based on published estimates of patent and sub-patent infectiousness, these results suggest that infections missed by RDTs during RACD would allow 50–71% of infections to mosquitoes to occur in this setting. Conclusion Malaria infections cluster around passively detected cases. The majority of infections are asymptomatic and of densities below the limit of detection of current RDTs. RACD using standard RDTs are unlikely to detect enough malaria infections to dramatically reduce transmission. In low transmission settings such as Namibia more sensitive field diagnostics or forms of focal presumptive treatment should be tested as strategies to reduce malaria transmission.
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