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Hast M, Mharakurwa S, Shields TM, Lubinda J, Searle K, Gwanzura L, Munyati S, Moss WJ. Characterizing human movement patterns using GPS data loggers in an area of persistent malaria in Zimbabwe along the Mozambique border. BMC Infect Dis 2022; 22:942. [PMID: 36522643 PMCID: PMC9756631 DOI: 10.1186/s12879-022-07903-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Human mobility is a driver for the reemergence or resurgence of malaria and has been identified as a source of cross-border transmission. However, movement patterns are difficult to measure in rural areas where malaria risk is high. In countries with malaria elimination goals, it is essential to determine the role of mobility on malaria transmission to implement appropriate interventions. METHODS A study was conducted in Mutasa District, Zimbabwe, to investigate human movement patterns in an area of persistent transmission along the Mozambique border. Over 1 year, a convenience sample of 20 participants/month was recruited from active malaria surveillance cohorts to carry an IgotU® GT-600 global positioning system (GPS) data logger during all daily activities. Consenting participants were tested for malaria at data logger distribution using rapid antigen diagnostic tests and completed a survey questionnaire. GPS data were analyzed using a trajectory analysis tool, and participant movement patterns were characterized throughout the study area and across the border into Mozambique using movement intensity maps, activity space plots, and statistical analyses. RESULTS From June 2016-May 2017, 184 participants provided movement tracks encompassing > 350,000 data points and nearly 8000 person-days. Malaria prevalence at logger distribution was 3.7%. Participants traveled a median of 2.8 km/day and spent a median of 4.6 h/day away from home. Movement was widespread within and outside the study area, with participants traveling up to 500 km from their homes. Indices of mobility were higher in the dry season than the rainy season (median km traveled/day = 3.5 vs. 2.2, P = 0.03), among male compared to female participants (median km traveled/day = 3.8 vs. 2.0, P = 0.0008), and among adults compared to adolescents (median total km traveled = 104.6 vs. 59.5, P = 0.05). Half of participants traveled outside the study area, and 30% traveled into Mozambique, including 15 who stayed in Mozambique overnight. CONCLUSIONS Study participants in Mutasa District, Zimbabwe, were highly mobile throughout the year. Many participants traveled long distances from home, including overnight trips into Mozambique, with clear implications for malaria control. Interventions targeted at mobile populations and cross-border transmission may be effective in preventing malaria introductions in this region.
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Affiliation(s)
- Marisa Hast
- grid.21107.350000 0001 2171 9311Johns Hopkins Bloomberg School of Public Health, Baltimore, MD USA
| | - Sungano Mharakurwa
- grid.418347.d0000 0004 8265 7435Biomedical Research and Training Institute, Harare, Zimbabwe ,grid.442719.d0000 0000 8930 0245Africa University, Old Mutare, Mutare, Zimbabwe
| | - Timothy M. Shields
- grid.21107.350000 0001 2171 9311Johns Hopkins Bloomberg School of Public Health, Baltimore, MD USA
| | - Jailos Lubinda
- grid.414659.b0000 0000 8828 1230Telethon Kids Institute, Malaria Atlas Project, Nedlands, WA Australia
| | - Kelly Searle
- grid.17635.360000000419368657School of Public Health, University of Minnesota, Minneapolis, MN USA
| | - Lovemore Gwanzura
- grid.418347.d0000 0004 8265 7435Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Shungu Munyati
- grid.418347.d0000 0004 8265 7435Biomedical Research and Training Institute, Harare, Zimbabwe
| | - William J. Moss
- grid.21107.350000 0001 2171 9311Johns Hopkins Bloomberg School of Public Health, Baltimore, MD USA
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Schaber KL, Kobayashi T, Hast M, Searle KM, Shields TM, Hamapumbu H, Lubinda J, Thuma PE, Lupiya J, Chaponda M, Munyati S, Gwanzura L, Mharakurwa S, Moss WJ, Wesolowski A. What Heterogeneities in Individual-level Mobility Are Lost During Aggregation? Leveraging GPS Logger Data to Understand Fine-scale and Aggregated Patterns of Mobility. Am J Trop Med Hyg 2022; 107:1145-1153. [PMID: 36252797 PMCID: PMC9709031 DOI: 10.4269/ajtmh.22-0202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 08/18/2022] [Indexed: 01/25/2023] Open
Abstract
Human movement drives spatial transmission patterns of infectious diseases. Population-level mobility patterns are often quantified using aggregated data sets, such as census migration surveys or mobile phone data. These data are often unable to quantify individual-level travel patterns and lack the information needed to discern how mobility varies by demographic groups. Individual-level datasets can capture additional, more precise, aspects of mobility that may impact disease risk or transmission patterns and determine how mobility differs across cohorts; however, these data are rare, particularly in locations such as sub-Saharan Africa. Using detailed GPS logger data collected from three sites in southern Africa, we explore metrics of mobility such as percent time spent outside home, number of locations visited, distance of locations, and time spent at locations to determine whether they vary by demographic, geographic, or temporal factors. We further create a composite mobility score to identify how well aggregated summary measures would capture the full extent of mobility patterns. Although sites had significant differences in all mobility metrics, no site had the highest mobility for every metric, a distinction that was not captured by the composite mobility score. Further, the effects of sex, age, and season on mobility were all dependent on site. No factor significantly influenced the number of trips to locations, a common way to aggregate datasets. When collecting and analyzing human mobility data, it is difficult to account for all the nuances; however, these analyses can help determine which metrics are most helpful and what underlying differences may be present.
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Affiliation(s)
- Kathryn L. Schaber
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Tamaki Kobayashi
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Marisa Hast
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Kelly M. Searle
- Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, Minnesota
| | - Timothy M. Shields
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | - Jailos Lubinda
- Telethon Kids Institute, Malaria Atlas Project, Nedlands, Australia
| | - Philip E. Thuma
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - James Lupiya
- The Tropical Diseases Research Centre, Ndola, Zambia
| | - Mike Chaponda
- The Tropical Diseases Research Centre, Ndola, Zambia
| | - Shungu Munyati
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Lovemore Gwanzura
- Biomedical Research and Training Institute, Harare, Zimbabwe
- College of Health Sciences, University of Zimbabwe, Harare, Zimbabwe
| | - Sungano Mharakurwa
- Biomedical Research and Training Institute, Harare, Zimbabwe
- College of Health, Agriculture and Natural Sciences, Africa University, Mutare, Zimbabwe
| | - William J. Moss
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Amy Wesolowski
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
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3
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Wesolowski A, Ippolito MM, Gebhardt ME, Ferriss E, Schue JL, Kobayashi T, Chaponda M, Kabuya JB, Muleba M, Mburu M, Matoba J, Musonda M, Katowa B, Lubinda M, Hamapumbu H, Simubali L, Mudenda T, Shields TM, Hackman A, Shiff C, Coetzee M, Koekemoer LL, Munyati S, Gwanzura L, Mutambu S, Stevenson JC, Thuma PE, Norris DE, Bailey JA, Juliano JJ, Chongwe G, Mulenga M, Simulundu E, Mharakurwa S, Agre P, Moss WJ. Policy Implications of the Southern and Central Africa International Center of Excellence for Malaria Research: Ten Years of Malaria Control Impact Assessments in Hypo-, Meso-, and Holoendemic Transmission Zones in Zambia and Zimbabwe. Am J Trop Med Hyg 2022; 107:68-74. [PMID: 36228913 PMCID: PMC9662215 DOI: 10.4269/ajtmh.21-1288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 05/28/2022] [Indexed: 11/07/2022] Open
Abstract
The International Centers of Excellence for Malaria Research (ICEMR) were established by the National Institute of Allergy and Infectious Diseases more than a decade ago to provide multidisciplinary research support to malaria control programs worldwide, operating in endemic areas and contributing technology, expertise, and ultimately policy guidance for malaria control and elimination. The Southern and Central Africa ICEMR has conducted research across three main sites in Zambia and Zimbabwe that differ in ecology, entomology, transmission intensity, and control strategies. Scientific findings led to new policies and action by the national malaria control programs and their partners in the selection of methods, materials, timing, and locations of case management and vector control. Malaria risk maps and predictive models of case detection furnished by the ICEMR informed malaria elimination programming in southern Zambia, and time series analyses of entomological and parasitological data motivated several major changes to indoor residual spray campaigns in northern Zambia. Along the Zimbabwe-Mozambique border, temporal and geospatial data are currently informing investigations into a recent resurgence of malaria. Other ICEMR findings pertaining to parasite and mosquito genetics, human behavior, and clinical epidemiology have similarly yielded immediate and long-term policy implications at each of the sites, often with generalizable conclusions. The ICEMR programs thereby provide rigorous scientific investigations and analyses to national control and elimination programs, without which the impediments to malaria control and their potential solutions would remain understudied.
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Affiliation(s)
- Amy Wesolowski
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Matthew M. Ippolito
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
- Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Mary E. Gebhardt
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Ellen Ferriss
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Jessica L. Schue
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Tamaki Kobayashi
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | | | | | | | | | | | | | | | | | | | | | | | - Andre Hackman
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Clive Shiff
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Maureen Coetzee
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand and National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Lizette L. Koekemoer
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand and National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Shungu Munyati
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Lovemore Gwanzura
- Biomedical Research and Training Institute, Harare, Zimbabwe
- University of Zimbabwe Faculty of Medicine and Health Sciences, Harare, Zimbabwe
| | | | - Jennifer C. Stevenson
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
- Macha Research Trust, Choma, Zambia
| | - Philip E. Thuma
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
- Macha Research Trust, Choma, Zambia
| | - Douglas E. Norris
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | - Jonathan J. Juliano
- University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | | | - Modest Mulenga
- Directorate of Research and Postgraduate Studies, Lusaka Apex Medical University, Lusaka, Zambia
| | | | - Sungano Mharakurwa
- Biomedical Research and Training Institute, Harare, Zimbabwe
- Africa University, Mutare, Zimbabwe
| | - Peter Agre
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - William J. Moss
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
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4
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Ippolito MM, Gebhardt ME, Ferriss E, Schue JL, Kobayashi T, Chaponda M, Kabuya JB, Muleba M, Mburu M, Matoba J, Musonda M, Katowa B, Lubinda M, Hamapumbu H, Simubali L, Mudenda T, Wesolowski A, Shields TM, Hackman A, Shiff C, Coetzee M, Koekemoer LL, Munyati S, Gwanzura L, Mutambu S, Stevenson JC, Thuma PE, Norris DE, Bailey JA, Juliano JJ, Chongwe G, Mulenga M, Simulundu E, Mharakurwa S, Agre PC, Moss WJ. Scientific Findings of the Southern and Central Africa International Center of Excellence for Malaria Research: Ten Years of Malaria Control Impact Assessments in Hypo-, Meso-, and Holoendemic Transmission Zones in Zambia and Zimbabwe. Am J Trop Med Hyg 2022; 107:55-67. [PMID: 36228903 PMCID: PMC9662223 DOI: 10.4269/ajtmh.21-1287] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 04/08/2022] [Indexed: 11/07/2022] Open
Abstract
For a decade, the Southern and Central Africa International Center of Excellence for Malaria Research has operated with local partners across study sites in Zambia and Zimbabwe that range from hypo- to holoendemic and vary ecologically and entomologically. The burden of malaria and the impact of control measures were assessed in longitudinal cohorts, cross-sectional surveys, passive and reactive case detection, and other observational designs that incorporated multidisciplinary scientific approaches: classical epidemiology, geospatial science, serosurveillance, parasite and mosquito genetics, and vector bionomics. Findings to date have helped elaborate the patterns and possible causes of sustained low-to-moderate transmission in southern Zambia and eastern Zimbabwe and recalcitrant high transmission and fatality in northern Zambia. Cryptic and novel mosquito vectors, asymptomatic parasite reservoirs in older children, residual parasitemia and gametocytemia after treatment, indoor residual spraying timed dyssynchronously to vector abundance, and stockouts of essential malaria commodities, all in the context of intractable rural poverty, appear to explain the persistent malaria burden despite current interventions. Ongoing studies of high-resolution transmission chains, parasite population structures, long-term malaria periodicity, and molecular entomology are further helping to lay new avenues for malaria control in southern and central Africa and similar settings.
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Affiliation(s)
- Matthew M. Ippolito
- Johns Hopkins University School of Medicine, Baltimore, Maryland
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Mary E. Gebhardt
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Ellen Ferriss
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Jessica L. Schue
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Tamaki Kobayashi
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | | | | | | | | | | | | | | | | | | | | | - Amy Wesolowski
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | - Andre Hackman
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Clive Shiff
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Maureen Coetzee
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand and National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Lizette L. Koekemoer
- Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand and National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Shungu Munyati
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Lovemore Gwanzura
- Biomedical Research and Training Institute, Harare, Zimbabwe
- University of Zimbabwe Faculty of Medicine and Health Sciences, Harare, Zimbabwe
| | | | - Jennifer C. Stevenson
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
- Macha Research Trust, Choma, Zambia
| | | | - Douglas E. Norris
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | - Jonathan J. Juliano
- University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | | | - Modest Mulenga
- Directorate of Research and Postgraduate Studies, Lusaka Apex Medical University, Lusaka, Zambia
| | | | - Sungano Mharakurwa
- Biomedical Research and Training Institute, Harare, Zimbabwe
- Africa University, Mutare, Zimbabwe
| | - Peter C. Agre
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - William J. Moss
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
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5
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Zvinoera K, Olaru ID, Khan P, Mutsvangwa J, Denkinger CM, Kampira V, Coutinho D, Mutunzi H, Pepukai M, Chikaka E, Zinyowera S, Mharakurwa S, Kranzer K. The impact of changing the diagnostic algorithm for TB in Manicaland, Zimbabwe. Public Health Action 2021; 11:196-201. [PMID: 34956848 DOI: 10.5588/pha.21.0040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 08/29/2021] [Indexed: 11/10/2022] Open
Abstract
SETTING Governmental health facilities performing TB diagnostics in Manicaland, Zimbabwe. OBJECTIVE To investigate the effect of making Xpert® MTB/RIF the primary TB diagnostic for all patients presenting with presumptive TB on 1) the number of samples investigated for TB, 2) the proportion testing TB-positive, and 3) the proportion of unsuccessful results over time. DESIGN This retrospective study used data from GeneX-pert downloads, laboratory registers and quality assurance reports between 1 January 2017 and 31 December 2018. RESULTS The total number of Xpert tests performed in Manicaland increased from 3,967 in the first quarter of 2017 to 7,011 in the last quarter of 2018. Mycobacterium tuberculosis DNA was detected in 4.9-8.6% of the samples investigated using Xpert, with a higher yield in 2017 than in 2018. The overall proportion of unsuccessful Xpert assays due to "no results", errors and invalid results was 6.3%, and highly variable across sites. CONCLUSION Roll out of more sensitive TB diagnostics does not necessarily result in an increase of microbiologically confirmed TB diagnosis. While the number of samples tested using Xpert increased, the proportion of TB-positive tests decreased. GeneXpert soft- and hardware infrastructure needs to be strengthened to reduce the rate of unsuccessful assays and therefore, costs and staff time.
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Affiliation(s)
- K Zvinoera
- Ministry of Health and Child Care, Mutare Provincial Hospital, Mutare, Zimbabwe
| | - I D Olaru
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, UK.,Biomedical Research and Training Institute, Harare, Zimbabwe
| | - P Khan
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, UK
| | - J Mutsvangwa
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - C M Denkinger
- Division of Tropical Medicine, Centre for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany.,German Centre for Infection Research (DZIF), partner site Heidelberg University Hospital, Heidelberg, Germany
| | - V Kampira
- Ministry of Health and Child Care, Mutare Provincial Hospital, Mutare, Zimbabwe
| | - D Coutinho
- Ministry of Health and Child Care, Mutare Provincial Hospital, Mutare, Zimbabwe
| | - H Mutunzi
- AIDS and TB Department, Ministry of Health and Child Care, Harare, Zimbabwe
| | - M Pepukai
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - E Chikaka
- Department of Health Sciences, College of Health and Natural Sciences, Africa University, Old Mutare, Zimbabwe
| | - S Zinyowera
- National Microbiology Reference Laboratory, Ministry of Health and Child Care, Harare, Zimbabwe
| | - S Mharakurwa
- Department of Health Sciences, College of Health and Natural Sciences, Africa University, Old Mutare, Zimbabwe
| | - K Kranzer
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, UK.,Biomedical Research and Training Institute, Harare, Zimbabwe.,Division of Infectious Diseases and Tropical Medicine, Medical Center of the University of Munich, Munich, Germany
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6
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Matambo R, Nyandoro G, Sandy C, Nkomo T, Mutero-Munyati S, Mharakurwa S, Chikaka E, Ngwenya M, Ndongwe G, Pepukai VM. Predictors of mortality and treatment success of multi-drug resistant and Rifampicin resistant tuberculosis in Zimbabwe: a retrospective cohort analysis of patients initiated on treatment during 2010 to 2015. Pan Afr Med J 2021; 39:128. [PMID: 34527144 PMCID: PMC8418161 DOI: 10.11604/pamj.2021.39.128.27726] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 04/29/2021] [Indexed: 11/11/2022] Open
Abstract
Introduction Zimbabwe is one of the 30 countries globally with a high burden of multidrug-resistant TB or rifampicin-resistant TB. The World Health Organization recommended that patients diagnosed with multidrug-resistant TB be treated with 20-24 month standardized second-line drugs since 2010. However, factors associated with mortality and treatment success have not been systematically evaluated in Zimbabwe. The Objective of the study was to assess factors associated with Mortality and treatment success among multidrug-resistant-TB patients registered and treated under the National Tuberculosis programme in Zimbabwe. Methods the study was conducted using secondary data routinely collected from the National tuberculosis (TB) programme. Categorical variables were summarised using frequencies and a generalized linear model with a log-link function and a Poisson distribution was used to assess factors associated with mortality and treatment success. The level of significance was set at P-Value < 0.05. Results patient antiretroviral therapy (ART) status was a significant associated factor of treatment success or failure (RRR = 3.92, p < 0.001). Patients who were not on ART had a high risk of death by 3.92 times compared to patients who were on ART. In the age groups 45 - 54 years (relative risk ratios (RRR) = 1.41, p = 0.048), the risk of death was increased by 1.41 times compared to other age groups. Patients aged 55 years and above (RRR = 1.55, p = 0.017), had a risk of dying increased by 1.55 times compared to other age groups. Diagnosis time duration of 8 - 30 days (RRR = 0.62, p = 0.022) was found to be protective, a shorter diagnosis time duration between 8 to 30 days reduced the risk of TB deaths by 0.62 times compared to longer periods. Missed TB doses of > 10% (RRR = 2.03, p < 0.001) increased the risk of MDR/RR-TB deaths by 2.03 times compared to missing TB doses of ≤ 10%. Conclusion not being on ART when HIV positive was a major significant predictor of mortality. Improving ART uptake among those ART-naïve and strategies aimed at improving treatment adherence are important in improving treatment success rates.
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Affiliation(s)
- Ronnie Matambo
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - George Nyandoro
- Community Medicine, College of Health Sciences, University of Zimbabwe, Harare, Zimbabwe
| | - Charles Sandy
- AIDS and Tuberculosis Department, Ministry of Health and Child Care, Harare, Zimbabwe
| | - Tendai Nkomo
- AIDS and Tuberculosis Department, Ministry of Health and Child Care, Harare, Zimbabwe
| | | | - Sungano Mharakurwa
- College of Health, Agriculture and Natural Sciences, Africa University, Mutare, Zimbabwe
| | - Elliot Chikaka
- College of Health, Agriculture and Natural Sciences, Africa University, Mutare, Zimbabwe
| | - Mkhokheli Ngwenya
- World Health Organisation, Zimbabwe Country Office, Harare, Zimbabwe
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7
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Mharakurwa S, Matsena-Zingoni Z, Mudare N, Matimba C, Gara TX, Makuwaza A, Maponga G, Munyati S, Gwanzura L, Mutambu SL, Mason P, Kobayashi T, Midzi N, Moss WJ, Ippolito MM. Steep Rebound of Chloroquine-Sensitive Plasmodium falciparum in Zimbabwe. J Infect Dis 2021; 223:306-309. [PMID: 32594154 DOI: 10.1093/infdis/jiaa368] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Accepted: 06/19/2020] [Indexed: 11/13/2022] Open
Abstract
Removal of chloroquine from national malaria formularies can lead to the reversion of resistant Plasmodium falciparum to wild-type. We report a steep decline in chloroquine-resistant P falciparum within 10 years of national discontinuation of chloroquine monotherapy in Zimbabwe. Drug resistance surveillance is a vital component of malaria control programs, and the experience with chloroquine in Zimbabwe and elsewhere in sub-Saharan Africa is illustrative of the potentially rapid and dramatic impact of drug policy on antimalarial resistance.
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Affiliation(s)
| | | | - Nobert Mudare
- Department of Health Sciences, Africa University, Mutare, Zimbabwe
| | | | | | - Aramu Makuwaza
- National Institute of Health Research Malaria Section, Harare, Zimbabwe
| | - Gladys Maponga
- National Institute of Health Research Malaria Section, Harare, Zimbabwe
| | - Shungu Munyati
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Lovemore Gwanzura
- Biomedical Research and Training Institute, Harare, Zimbabwe.,College of Health Sciences, University of Zimbabwe, Harare, Zimbabwe
| | - Susan L Mutambu
- Department of Health Sciences, Africa University, Mutare, Zimbabwe
| | - Peter Mason
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Tamaki Kobayashi
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.,Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Nicholas Midzi
- National Institute of Health Research Malaria Section, Harare, Zimbabwe
| | - William J Moss
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.,Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Matthew M Ippolito
- Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.,Division of Clinical Pharmacology and Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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8
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Matambo R, Mutero-Munyati S, Pepuka VM, Nkomo T, Sandy C, Ngwenya M, Ndongwe G, Chikaka E, Mharakurwa S, Nyandoro G. The role of bacteriological monitoring using culture and drug susceptibility tests (CDST) on treatment outcomes among MDR/RR-TB patients on treatment: a cohort analysis of patients enrolled on treatment 2010-2015 in Zimbabwe. Pan Afr Med J 2021; 39:97. [PMID: 34466199 PMCID: PMC8379410 DOI: 10.11604/pamj.2021.39.97.26796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Accepted: 05/10/2021] [Indexed: 11/11/2022] Open
Abstract
Introduction an estimated 25% of the world population is infected with Mycobacterium tuberculosis. In 2017, new tuberculosis cases were estimated at 10 million, while 1.6 million tuberculosis related deaths were recorded, 25% residing in Africa. Treatment outcomes of multi drug resistant Tuberculosis patients in Zimbabwe has been well documented but the role of bacteriological monitoring on treatment outcomes has not been systematically evaluated. The objective of the study was to determine the role of bacteriological monitoring using culture and drug susceptibility tests on treatment outcomes among patients with multi drug resistant tuberculosis. Methods a retrospective, secondary data analysis was conducted using routinely collected data of patients with multi drug resistant TB in Zimbabwe. Frequencies were used to summarize categorical variables and a generalized linear model with a log-link function and a Poisson distribution was used to assess factors associated with unfavourable outcomes. The level of significance was set at P-Value<0.05. Results about the study collected data from 473 records of patients with an average age of 36.35 years. Forty-nine percent (49%) were male and 51% were female. Results showed that when a patient has baseline culture result missing, has no culture conversion result, regardless of having a follow up culture and drug susceptibility test result, the risk of developing unfavourable outcomes increase by 3.9 times compared to a patient who has received all the three (3) bacteriological monitoring tests. Conclusion results highlights the need for consistent bacteriological monitoring of patients to avert unfavourable treatment outcomes.
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Affiliation(s)
- Ronnie Matambo
- Biomedical Research and Training Institute, 10 Seagrave Ave, Harare, Zimbabwe
| | | | | | - Tendai Nkomo
- Ministry of Health and Child Care, AIDS and TB, Harare, Zimbabwe
| | - Charles Sandy
- Ministry of Health and Child Care, AIDS and TB, Harare, Zimbabwe
| | | | | | - Elliot Chikaka
- Africa University, Faculty of Health Agriculture and Natural Resources, Mutare, Zimbabwe
| | - Sungano Mharakurwa
- Africa University, Faculty of Health Agriculture and Natural Resources, Mutare, Zimbabwe
| | - George Nyandoro
- AIDS and TB Department, Ministry of Health and Child Care, Harare, Zimbabwe
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9
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Mulenga MC, Sitali L, Ciubotariu II, Hawela MB, Hamainza B, Chipeta J, Mharakurwa S. Decreased prevalence of the Plasmodium falciparum Pfcrt K76T and Pfmdr1 and N86Y mutations post-chloroquine treatment withdrawal in Katete District, Eastern Zambia. Malar J 2021; 20:329. [PMID: 34320992 PMCID: PMC8317340 DOI: 10.1186/s12936-021-03859-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 07/19/2021] [Indexed: 12/30/2022] Open
Abstract
Background In 2002, Zambia withdrew chloroquine as first-line treatment for Plasmodium falciparum malaria due to increased treatment failure and worldwide spread of chloroquine resistance. The artemisinin combination regimen, artemether–lumefantrine, replaced chloroquine (CQ) as first choice malaria treatment. The present study determined the prevalence of CQ resistance molecular markers in the Pfcrt and Pfmdr1 genes in Eastern Zambia at 9 and 13 years after the removal of drug pressure. Methods Samples collected from Katete District during the drug therapeutic efficacy assessments conducted in 2012 and 2016 were assayed by polymerase chain reaction (PCR) and restriction fragment length polymorphisms (RFLP) to determine the prevalence of genetic mutations, K76T on the Pfcrt gene and N86Y on the Pfmdr1 gene. A total of 204 P. falciparum-positive DBS samples collected at these two time points were further analysed. Results Among the samples analysed for Pfcrt K76T and Pfmdr1 N86Y in the present study, 112 (82.4%) P. falciparum-infected samples collected in 2012 were successfully amplified for Pfcrt and 94 (69.1%) for Pfmdr1, while 69 (65.7%) and 72 (68.6%) samples from 2016 were successfully amplified for Pfcrt and Pfmdr1, respectively. In 2012, the prevalence of Pfcrt 76K (sensitive) was 97.3%, 76T (resistant) was 1.8%, and 0.8% had both 76K and 76T codons (mixed). Similarly in 2012, the prevalence of Pfmdr1 86N (sensitive) was 97.9% and 86Y (resistant) was 2.1%. In the 2016 samples, the prevalence of the respective samples was 100% Pfcrt 76K and Pfmdr1 86N. Conclusion This study shows that there was a complete recovery of chloroquine-sensitive parasites by 2016 in Katete District, Eastern Zambia, 13 years following the withdrawal of CQ in the country. These findings add to the body of evidence for a fitness cost in CQ-resistant P. falciparum in Zambia and elsewhere. Further studies are recommended to monitor resistance countrywide and explore the feasibility of integration of the former best anti-malarial in combination therapy in the future.
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Affiliation(s)
- Mwenda C Mulenga
- PATH Malaria Control and Elimination Partnership in Africa (MACEPA), National Malaria Elimination Centre, Ministry of Health, Chainama Grounds, Lusaka, Zambia.
| | - Lungowe Sitali
- School of Health Sciences, Biomedical Sciences Department, Ridgeway campus, Lusaka, Zambia.,School of Medicine, University Teaching Hospital Malaria Research Unit (SMUTH-MRU), Lusaka, Zambia
| | - Ilinca I Ciubotariu
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Moonga B Hawela
- Malaria Elimination Centre, Ministry of Health, Chainama Hospital and College Grounds, Lusaka, Zambia
| | - Busiku Hamainza
- Malaria Elimination Centre, Ministry of Health, Chainama Hospital and College Grounds, Lusaka, Zambia
| | - James Chipeta
- School of Medicine, University Teaching Hospital Malaria Research Unit (SMUTH-MRU), Lusaka, Zambia
| | - Sungano Mharakurwa
- College of Health, Agriculture and Natural Sciences, Africa University, Mutare, Zimbabwe
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10
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Gregson S, Moorhouse L, Dadirai T, Sheppard H, Mayini J, Beckmann N, Skovdal M, Dzangare J, Moyo B, Maswera R, Pinsky BA, Mharakurwa S, Francis I, Mugurungi O, Nyamukapa C. Comprehensive investigation of sources of misclassification errors in routine HIV testing in Zimbabwe. J Int AIDS Soc 2021; 24:e25700. [PMID: 33882190 PMCID: PMC8059712 DOI: 10.1002/jia2.25700] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 02/26/2021] [Accepted: 03/10/2021] [Indexed: 12/11/2022] Open
Abstract
INTRODUCTION Misclassification errors have been reported in rapid diagnostic HIV tests (RDTs) in sub-Saharan African countries. These errors can lead to missed opportunities for prevention-of-mother-to-child-transmission (PMTCT), early infant diagnosis and adult HIV-prevention, unnecessary lifelong antiretroviral treatment (ART) and wasted resources. Few national estimates or systematic quantifications of sources of errors have been produced. We conducted a comprehensive assessment of possible sources of misclassification errors in routine HIV testing in Zimbabwe. METHODS RDT-based HIV test results were extracted from routine PMTCT programme records at 62 sites during national antenatal HIV surveillance in 2017. Positive- (PPA) and negative-percent agreement (NPA) for HIV RDT results and the false-HIV-positivity rate for people with previous HIV-positive results ("known-positives") were calculated using results from external quality assurance testing done for HIV surveillance purposes. Data on indicators of quality management systems, RDT kit performance under local climatic conditions and user/clerical errors were collected using HIV surveillance forms, data-loggers and a Smartphone camera application (7 sites). Proportions of cases with errors were compared for tests done in the presence/absence of potential sources of errors. RESULTS NPA was 99.9% for both pregnant women (N = 17224) and male partners (N = 2173). PPA was 90.0% (N = 1187) and 93.4% (N = 136) for women and men respectively. 3.5% (N = 1921) of known-positive individuals on ART were HIV negative. Humidity and temperature exceeding manufacturers' recommendations, particularly in storerooms (88.6% and 97.3% respectively), and premature readings of RDT output (56.0%) were common. False-HIV-negative cases, including interpretation errors, occurred despite staff training and good algorithm compliance, and were not reduced by existing external or internal quality assurance procedures. PPA was lower when testing room humidity exceeded 60% (88.0% vs. 93.3%; p = 0.007). CONCLUSIONS False-HIV-negative results were still common in Zimbabwe in 2017 and could be reduced with HIV testing algorithms that use RDTs with higher sensitivity under real-world conditions and greater practicality under busy clinic conditions, and by strengthening proficiency testing procedures in external quality assurance systems. New false-HIV-positive RDT results were infrequent but earlier errors in testing may have resulted in large numbers of uninfected individuals being on ART.
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Affiliation(s)
- Simon Gregson
- Department of Infectious Disease Epidemiology, Imperial College London School of Public Health, London, UK
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Louisa Moorhouse
- Department of Infectious Disease Epidemiology, Imperial College London School of Public Health, London, UK
| | - Tawanda Dadirai
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Haynes Sheppard
- Global Solutions for Infectious Diseases, San Francisco, CA, USA
| | - Justin Mayini
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | | | | | - Janet Dzangare
- Zimbabwe Ministry of Health and Child Care, Harare, Zimbabwe
| | - Brian Moyo
- Zimbabwe Ministry of Health and Child Care, Harare, Zimbabwe
| | | | | | | | - Ian Francis
- Global Solutions for Infectious Diseases, San Francisco, CA, USA
| | - Owen Mugurungi
- Zimbabwe Ministry of Health and Child Care, Harare, Zimbabwe
| | - Constance Nyamukapa
- Department of Infectious Disease Epidemiology, Imperial College London School of Public Health, London, UK
- Biomedical Research and Training Institute, Harare, Zimbabwe
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11
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Chaponda EB, Mharakurwa S, Michelo C, Bruce J, Chandramoha D, Matthew Chico R. Sulfadoxine-pyrimethamine parasitological efficacy against Plasmodium falciparum among pregnant women and molecular markers of resistance in Zambia: an observational cohort study. Malar J 2021; 20:61. [PMID: 33482823 PMCID: PMC7821718 DOI: 10.1186/s12936-021-03596-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 01/15/2021] [Indexed: 11/10/2022] Open
Abstract
Background The World Health Organization recommends the provision of intermittent preventive treatment during pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP) at 4-week intervals from gestational week 13 to delivery in areas of moderate to high malaria transmission intensity. However, the effect of IPTp-SP has been compromised in some areas due to parasite resistance, raising the importance of parasitological and chemoprophylactic surveillance, and monitoring SP-resistance markers in the Plasmodium falciparum population. Methods Between November 2013 and April 2014 in Nchelenge, Zambia, 1086 pregnant women received IPTp-SP at antenatal-care bookings. Blood samples were collected on day 0, and on day 28 post-treatment to test for malaria parasites and to estimate SP parasitological efficacy in the treatment and prevention of parasitaemia. A random sample of 96, day 0 malaria-positive samples were analysed to estimate the prevalence of SP-resistance markers in the P. falciparum population. Results The overall parasitological and prophylactic failure among women who had paired day 0 and day 28 blood slides was 18.6% (95% CI 15.5, 21.8; 109 of 590). Among pregnant women who had asymptomatic parasitaemia on day 0, the day 28 PCR-uncorrected parasitological failure was 30.0% (95% CI 23.7, 36.2; 62 of 207) and the day 28 PCR-corrected parasitological failure was 15.6% (95% CI: 10.6, 20.6; 32 of 205). Among women who tested negative at day 0, 12.3% (95% CI: 9.0, 15.6; 47 of 383) developed parasitaemia at day 28. Among the 96 malaria-positive samples assayed from day 0, 70.8% (95% CI: 60.8, 79.2) contained the DHPS double (Gly-437 + Glu-540) mutation and 92.7% (95% CI: 85.3, 96.5) had the DHFR triple (Asn-108 + Ile-51 + Arg-59) mutation. The quintuple mutation (DHFR triple + DHPS double) and the sextuple mutant (DHFR triple + DHPS double + Arg-581) were found among 68.8% (95% CI: 58.6, 77.3) and 9.4% (95% CI: 4.2, 16.0) of samples, respectively. Conclusion The parasitological and chemoprophylactic failure of SP, and the prevalence of resistance markers in Nchelenge is alarmingly high. Alternative therapies are urgently needed to safeguard pregnant women against malarial infection.
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Affiliation(s)
| | | | - Charles Michelo
- Department of Epidemiology, School of Public Health, University of Zambia, Lusaka, Zambia.,Strategic Centre for Health Systems Metrics and Evaluations, School of Public Health, University of Zambia, Lusaka, Zambia
| | - Jane Bruce
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Daniel Chandramoha
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - R Matthew Chico
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
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12
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Mudare N, Matsena-Zingoni Z, Makuwaza A, Mamini E, Munyati SS, Gwanzura L, Midzi N, Mutambu SL, Mason P, Kobayashi T, Mharakurwa S. Detecting Plasmodium falciparum in community surveys: a comparison of Paracheck Pf® Test and ICT Malaria Pf® Cassette Test to polymerase chain reaction in Mutasa District, Zimbabwe. Malar J 2021; 20:14. [PMID: 33407488 PMCID: PMC7789522 DOI: 10.1186/s12936-020-03536-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 12/07/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Microscopy and rapid diagnostic tests (RDTs) are the main techniques used to diagnose malaria. While microscopy is considered the gold standard, RDTs have established popularity as they allow for rapid diagnosis with minimal technical skills. This study aimed to compare the diagnostic performance of two Plasmodium falciparum histidine-rich protein 2 (PfHRP2)-based RDTs (Paracheck Pf® Test (Paracheck) and Malaria Pf™ ICT (ICT)) to polymerase chain reaction (PCR) in a community survey. METHODS A cross-sectional study was conducted between October 2012 and December 2014 in Mutasa District, Manicaland Province, eastern Zimbabwe. Households were randomly selected using satellite imagery, and 224 households were visited. Residents present in the household on the date of the visit were recruited for the study. Participants of all age groups from the selected households were screened with Paracheck and ICT RDTs in parallel. Dried blood spots (DBS) and thin and thick smears were collected. Parasite DNA extracted from the DBS was subjected to nested PCR targeting the Plasmodium cytochrome b mitochondrial gene. Data analysis was performed using the Cohen's Kappa test to determine the interrater agreement and the sensitivity and specificity of the diagnostic test were reported. RESULTS Results from a total of 702 participants were analysed. Most were females, 397 (57%), and the median age of participants was 21 years with an interquartile range of 9-39 years. Of those who were screened, 8 (1.1%), 35 (5.0%), and 21 (2.9%) were malaria parasite positive by microscopy, RDT and PCR, respectively. Paracheck and ICT RDTs had a 100% agreement. Comparing RDT and PCR results, 34 participants (4.8%) had discordant results. Most of the discordant cases were RDT positive but PCR negative (n = 24). Half of those RDT positive, but PCR negative individuals reported anti-malarials to use in the past month, which is significantly higher than reported anti-malarial drug use in the population (p < 0.001). The participant was febrile on the day of the visit, but relying on PfHRP2-based RDT would miss this case. Among the diagnostic methods evaluated, with reference to PCR, the sensitivity was higher with the RDT (52.4%) while specificity was higher with the microscopy (99.9%). The positive predictive value (PPV) was higher with the microscopy (87.5%), while the negative predictive values were similar for both microscopy and RDTs (98%). Overall, a strong correlated agreement with PCR was observed for the microscopy (97.9%) and the RDTs (95.2%). CONCLUSIONS Paracheck and ICT RDTs showed 100% agreement and can be used interchangeably. As malaria transmission declines and Zimbabwe aims to reach malaria elimination, management of infected individuals with low parasitaemia as well as non-P. falciparum infection can be critical.
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Affiliation(s)
| | | | | | - Edmore Mamini
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | | | - Lovemore Gwanzura
- Biomedical Research and Training Institute, Harare, Zimbabwe.,University of Zimbabwe, College of Health Sciences, Institute of Continuing Health Education, Harare, Zimbabwe
| | | | | | - Peter Mason
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Tamaki Kobayashi
- Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Sungano Mharakurwa
- Africa University, Mutare, Zimbabwe. .,Biomedical Research and Training Institute, Harare, Zimbabwe.
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13
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Matambo R, Takarinda KC, Thekkur P, Sandy C, Mharakurwa S, Makoni T, Ncube R, Charambira K, Zishiri C, Ngwenya M, Nyathi S, Chiteka A, Chikaka E, Mutero-Munyati S. Treatment outcomes of multi drug resistant and rifampicin resistant Tuberculosis in Zimbabwe: A cohort analysis of patients initiated on treatment during 2010 to 2015. PLoS One 2020; 15:e0230848. [PMID: 32353043 PMCID: PMC7192497 DOI: 10.1371/journal.pone.0230848] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 03/10/2020] [Indexed: 11/18/2022] Open
Abstract
Background Zimbabwe is one of the thirty countries globally with a high burden of multidrug-resistant tuberculosis (TB) or rifampicin-resistant TB (MDR/RR-TB). Since 2010, patients diagnosed with MDR/RR-TB are being treated with 20–24 months of standardized second-line drugs (SLDs). The profile, management and factors associated with unfavourable treatment outcomes of MDR/RR TB have not been systematically evaluated in Zimbabwe. Objective To assess treatment outcomes and factors associated with unfavourable outcomes among MDR/RR-TB patients registered and treated under the National Tuberculosis Programme in all the district hospitals and urban healthcare facilities in Zimbabwe between January 2010 and December 2015. Methods A cohort study using routinely collected programme data. The ‘death’, ‘loss to follow-up’ (LTFU), ‘failure’ and ‘not evaluated’ were considered as “unfavourable outcome”. A generalized linear model with a log-link and binomial distribution or a Poisson distribution with robust error variances were used to assess factors associated with “unfavourable outcome”. The unadjusted and adjusted relative risks were calculated as a measure of association. A 𝑝value< 0.05 was considered statistically significant. Results Of the 473 patients in the study, the median age was 34 years [interquartile range, 29–42] and 230 (49%) were males. There were 352 (74%) patients co-infected with HIV, of whom 321 (91%) were on antiretroviral therapy (ART). Severe adverse events (SAEs) were recorded in 118 (25%) patients; mostly hearing impairments (70%) and psychosis (11%). Overall, 184 (39%) patients had ‘unfavourable’ treatment outcomes [125 (26%) were deaths, 39 (8%) were lost to follow-up, 4 (<1%) were failures and 16 (3%) not evaluated]. Being co-infected with HIV but not on ART [adjusted relative risk (aRR) = 2.60; 95% CI: 1.33–5.09] was independently associated with unfavourable treatment outcomes. Conclusion The high unfavourable treatment outcomes among MDR/RR-TB patients on standardized SLDs were coupled with a high occurrence of SAEs in this predominantly HIV co-infected cohort. Switching to individualized all oral shorter treatment regimens should be considered to limit SAEs and improve treatment outcomes. Improving the ART uptake and timeliness of ART initiation can reduce unfavourable outcomes.
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Affiliation(s)
- Ronnie Matambo
- International Union against Tuberculosis & Lung Disease, Harare, Zimbabwe
- * E-mail:
| | - Kudakwashe C. Takarinda
- Centre for Operational Research, International Union against Tuberculosis & Lung Disease, Paris, France
- AIDS and TB Department, Ministry of Health & Child Care, Harare, Zimbabwe
| | - Pruthu Thekkur
- Centre for Operational Research, International Union against Tuberculosis & Lung Disease, Paris, France
- The Union South East Asia (The USEA) Office, New Delhi, India
| | - Charles Sandy
- AIDS and TB Department, Ministry of Health & Child Care, Harare, Zimbabwe
| | - Sungano Mharakurwa
- College of Health, Agriculture and Natural Sciences, Africa University, Mutare, Zimbabwe
| | - Talent Makoni
- AIDS and TB Department, Ministry of Health & Child Care, Harare, Zimbabwe
| | - Ronald Ncube
- International Union against Tuberculosis & Lung Disease, Harare, Zimbabwe
| | - Kelvin Charambira
- International Union against Tuberculosis & Lung Disease, Harare, Zimbabwe
| | | | - Mkhokheli Ngwenya
- World Health Organisation, Zimbabwe Country Office, Harare, Zimbabwe
| | - Saziso Nyathi
- Health Services Department, City of Bulawayo, Zimbabwe
| | - Albert Chiteka
- College of Health, Agriculture and Natural Sciences, Africa University, Mutare, Zimbabwe
| | - Elliot Chikaka
- College of Health, Agriculture and Natural Sciences, Africa University, Mutare, Zimbabwe
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14
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Kobayashi T, Jain A, Liang L, Obiero JM, Hamapumbu H, Stevenson JC, Thuma PE, Lupiya J, Chaponda M, Mulenga M, Mamini E, Mharakurwa S, Gwanzura L, Munyati S, Mutambu S, Felgner P, Davies DH, Moss WJ. Distinct Antibody Signatures Associated with Different Malaria Transmission Intensities in Zambia and Zimbabwe. mSphere 2019; 4:e00061-19. [PMID: 30918058 PMCID: PMC6437277 DOI: 10.1128/mspheredirect.00061-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 02/08/2019] [Indexed: 12/30/2022] Open
Abstract
Antibodies to Plasmodium falciparum are specific biomarkers that can be used to monitor parasite exposure over broader time frames than microscopy, rapid diagnostic tests, or molecular assays. Consequently, seroprevalence surveys can assist with monitoring the impact of malaria control interventions, particularly in the final stages of elimination, when parasite incidence is low. The protein array format to measure antibodies to diverse P. falciparum antigens requires only small sample volumes and is high throughput, permitting the monitoring of malaria transmission on large spatial and temporal scales. We expanded the use of a protein microarray to assess malaria transmission in settings beyond those with a low malaria incidence. Antibody responses in children and adults were profiled, using a P. falciparum protein microarray, through community-based surveys in three areas in Zambia and Zimbabwe at different stages of malaria control and elimination. These three epidemiological settings had distinct serological profiles reflective of their malaria transmission histories. While there was little correlation between transmission intensity and antibody signals (magnitude or breadth) in adults, there was a clear correlation in children younger than 5 years of age. Antibodies in adults appeared to be durable even in the absence of significant recent transmission, whereas antibodies in children provided a more accurate picture of recent levels of transmission intensity. Seroprevalence studies in children could provide a valuable marker of progress toward malaria elimination.IMPORTANCE As malaria approaches elimination in many areas of the world, monitoring the effect of control measures becomes more important but challenging. Low-level infections may go undetected by conventional tests that depend on parasitemia, particularly in immune individuals, who typically show no symptoms of malaria. In contrast, antibodies persist after parasitemia and may provide a more accurate picture of recent exposure. Only a few parasite antigens-mainly vaccine candidates-have been evaluated in seroepidemiological studies. We examined antibody responses to 500 different malaria proteins in blood samples collected through community-based surveillance from areas with low, medium, and high malaria transmission intensities. The breadth of the antibody responses in adults was broad in all three settings and was a poor correlate of recent exposure. In contrast, children represented a better sentinel population for monitoring recent malaria transmission. These data will help inform the use of multiplex serology for malaria surveillance.
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Affiliation(s)
- Tamaki Kobayashi
- Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Aarti Jain
- Vaccine Research & Development Center, Department of Physiology & Biophysics, School of Medicine, University of California, Irvine, Irvine, California, USA
| | - Li Liang
- Vaccine Research & Development Center, Department of Physiology & Biophysics, School of Medicine, University of California, Irvine, Irvine, California, USA
| | - Joshua M Obiero
- Vaccine Research & Development Center, Department of Physiology & Biophysics, School of Medicine, University of California, Irvine, Irvine, California, USA
| | | | - Jennifer C Stevenson
- Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
- Macha Research Trust, Choma, Zambia
| | - Philip E Thuma
- Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
- Macha Research Trust, Choma, Zambia
| | - James Lupiya
- Tropical Diseases Research Centre, Ndola, Zambia
| | | | | | - Edmore Mamini
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | | | | | - Shungu Munyati
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Susan Mutambu
- National Institute of Health Research, Harare, Zimbabwe
| | - Philip Felgner
- Vaccine Research & Development Center, Department of Physiology & Biophysics, School of Medicine, University of California, Irvine, Irvine, California, USA
| | - D Huw Davies
- Vaccine Research & Development Center, Department of Physiology & Biophysics, School of Medicine, University of California, Irvine, Irvine, California, USA
| | - William J Moss
- Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
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15
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Kanyangarara M, Hamapumbu H, Mamini E, Lupiya J, Stevenson JC, Mharakurwa S, Chaponda M, Thuma PE, Gwanzura L, Munyati S, Mulenga M, Norris DE, Moss WJ. Malaria knowledge and bed net use in three transmission settings in southern Africa. Malar J 2018; 17:41. [PMID: 29351795 PMCID: PMC5775538 DOI: 10.1186/s12936-018-2178-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 01/09/2018] [Indexed: 12/03/2022] Open
Abstract
Background Insecticide-treated nets (ITNs) reduce malaria morbidity and mortality in endemic areas. Despite increasing availability, the use of ITNs remains limited in some settings. Poor malaria knowledge is a barrier to the widespread use of ITNs. The goal of this study was to assess the levels of malaria knowledge and evaluate factors associated with bed net use among individuals residing in three regions of southern Africa with different levels of malaria transmission and control. Methods A cross-sectional study was conducted on a sample of 7535 residents recruited from 2066 households in Mutasa District, Zimbabwe (seasonal malaria transmission), Choma District, Zambia (low transmission) and Nchelenge District, Zambia (high transmission), between March 2012 and March 2017. A standardized questionnaire was used to collect data on demographics, malaria-related knowledge and use of preventive measures. Multivariate logistic regression analyses were used to assess determinants of bed net use. Results Most of the 3836 adult participants correctly linked mosquito bites to malaria (85.0%), mentioned at least one malaria symptom (95.5%) and knew of the benefit of sleeping under an ITN. Bed net ownership and use were highest in Choma and Nchelenge Districts and lowest in Mutasa District. In multivariate analyses, knowledge of ITNs was associated with a 30–40% increased likelihood of bed net use after adjusting for potential confounders across all sites. Other factors significantly associated with bed net use were age, household size and socioeconomic status, although the direction, strength and size of association varied by study site. Importantly, participants aged 5–14 years had reduced odds of sleeping under a bed net compared to children younger than 5 years. Conclusion Relevant knowledge of ITNs translated into the expected preventive behaviour of sleeping under a bed net, underscoring the need for continued health messaging on malaria prevention. The implementation and delivery of malaria control and elimination interventions needs to consider socioeconomic equity gaps, and target school-age children to ensure access to and improve utilization of ITNs.
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Affiliation(s)
- Mufaro Kanyangarara
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
| | | | - Edmore Mamini
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - James Lupiya
- Tropical Disease Research Centre, Ndola Central Hospital, Ndola, Zambia
| | - Jennifer C Stevenson
- Macha Research Trust, Macha, Choma District, Zambia.,Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | | | - Mike Chaponda
- Tropical Disease Research Centre, Ndola Central Hospital, Ndola, Zambia
| | - Philip E Thuma
- Macha Research Trust, Macha, Choma District, Zambia.,Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Lovemore Gwanzura
- Department of Medical Laboratory Sciences, University of Zimbabwe College of Health Sciences, Harare, Zimbabwe
| | - Shungu Munyati
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Modest Mulenga
- Tropical Disease Research Centre, Ndola Central Hospital, Ndola, Zambia
| | - Douglas E Norris
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - William J Moss
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.,Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
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16
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Searle KM, Katowa B, Kobayashi T, Siame MNS, Mharakurwa S, Carpi G, Norris DE, Stevenson JC, Thuma PE, Moss WJ. Distinct parasite populations infect individuals identified through passive and active case detection in a region of declining malaria transmission in southern Zambia. Malar J 2017; 16:154. [PMID: 28420399 PMCID: PMC5395854 DOI: 10.1186/s12936-017-1810-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 04/08/2017] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Substantial reductions in the burden of malaria have been documented in parts of sub-Saharan Africa, with elimination strategies and goals being formulated in some regions. Within this context, understanding the epidemiology of low-level malaria transmission is crucial to achieving and sustaining elimination. A 24 single-nucleotide-polymorphism Plasmodium falciparum molecular barcode was used to characterize parasite populations from infected individuals identified through passive and active case detection in an area approaching malaria elimination in southern Zambia. METHODS The study was conducted in the catchment area of Macha Hospital in Choma District, Southern Province, Zambia, where the parasite prevalence declined over the past decade, from 9.2% in 2008 to less than 1% in 2013. Parasite haplotypes from actively detected, P. falciparum-infected participants enrolled in a serial cross-sectional, community-based cohort study from 2008 to 2013 and from passively detected, P. falciparum-infected individuals enrolled at five rural health centres from 2012 to 2015 were compared. Changes in P. falciparum genetic relatedness, diversity and complexity were analysed as malaria transmission declined. RESULTS Actively detected cases identified in the community were most commonly rapid diagnostic test negative, asymptomatic and had submicroscopic parasitaemia. Phylogenetic reconstruction using concatenated 24 SNP barcode revealed a separation of parasite haplotypes from passively and actively detected infections, consistent with two genetically distinct parasite populations. For passively detected infections identified at health centres, the proportion of detectable polyclonal infections was consistently low in all seasons, in contrast with actively detected infections in which the proportion of polyclonal infections was high. The mean genetic divergence for passively detected infections was 34.5% for the 2012-2013 transmission season, 37.8% for the 2013-2014 season, and 30.8% for the 2014-2015 season. The mean genetic divergence for actively detected infections was 22.3% in the 2008 season and 29.0% in the 2008-2009 season and 9.9% across the 2012-2014 seasons. CONCLUSIONS Distinct parasite populations were identified among infected individuals identified through active and passive surveillance, suggesting that infected individuals detected through active surveillance may not have contributed substantially to ongoing transmission. As parasite prevalence and diversity within these individuals declined, resource-intensive efforts to identify the chronically infected reservoir may not be necessary to eliminate malaria in this setting.
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Affiliation(s)
- Kelly M Searle
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.
| | - Ben Katowa
- Macha Research Trust, Choma District, Zambia
| | - Tamaki Kobayashi
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | | | | | - Giovanna Carpi
- Johns Hopkins Malaria Research Institute, Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Douglas E Norris
- Johns Hopkins Malaria Research Institute, Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Jennifer C Stevenson
- Macha Research Trust, Choma District, Zambia.,Johns Hopkins Malaria Research Institute, Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Philip E Thuma
- Macha Research Trust, Choma District, Zambia.,Johns Hopkins Malaria Research Institute, Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - William J Moss
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.,Johns Hopkins Malaria Research Institute, Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
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17
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Mharakurwa S, Rangarira R, Murahwa FC, Chandiwana SK. Status of chloroquine efficacy against falciparum malaria in the Mola area of Kariba district, Zimbabwe. Annals of Tropical Medicine & Parasitology 2016. [DOI: 10.1080/00034983.1998.11813325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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18
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Chaponda EB, Chico RM, Bruce J, Michelo C, Vwalika B, Mharakurwa S, Chaponda M, Chipeta J, Chandramohan D. Malarial Infection and Curable Sexually Transmitted and Reproductive Tract Infections Among Pregnant Women in a Rural District of Zambia. Am J Trop Med Hyg 2016; 95:1069-1076. [PMID: 27672205 DOI: 10.4269/ajtmh.16-0370] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 08/09/2016] [Indexed: 11/07/2022] Open
Abstract
Malarial infection and curable sexually transmitted and reproductive tract infections (STIs/RTIs) are important causes of adverse birth outcomes. Reducing the burden of these infections in pregnancy requires interventions that can be easily integrated into the antenatal care (ANC) package. However, efforts to integrate the control of malarial infection and curable STIs/RTIs in pregnancy have been hampered by a lack of evidence related to their coinfection. Thus, we investigated the prevalence of coinfection among pregnant women of rural Zambia. A prospective cohort study was conducted in Nchelenge District, Zambia, involving 1,086 first ANC attendees. We screened participants for peripheral malarial infection and curable STIs/RTIs (syphilis, Chlamydia, gonorrhea, trichomoniasis, and bacterial vaginosis), and collected relevant sociodemographic data at booking. Factors associated with malarial and STI/RTI coinfection were explored using univariate and multivariate regression models. Among participants with complete results (N = 1,071), 38.7% (95% confidence interval [CI] = 35.7-41.6) were coinfected with malaria parasites and at least one STI/RTI; 18.9% (95% CI = 16.5-21.2) were infected with malaria parasites only; 26.0% (95% CI = 23.5-28.8) were infected with at least one STI/RTI but no malaria parasites, and 16.4% (95% CI = 14.1-18.6) had no infection. Human immunodeficiency virus (HIV)-infected women had a higher risk of being coinfected than HIV-uninfected women (odds ratio [OR] = 3.59 [95% CI = 1.73-7.48], P < 0.001). The prevalence of malarial and STI/RTI coinfection was high in this population. An integrated approach to control malarial infection and STIs/RTIs is needed to reduce this dual burden in pregnancy.
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Affiliation(s)
- Enesia Banda Chaponda
- Department of Biological Sciences, University of Zambia, Lusaka, Zambia. .,Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - R Matthew Chico
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Jane Bruce
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Charles Michelo
- Department of Public Health, University of Zambia School of Medicine, Lusaka, Zambia
| | - Bellington Vwalika
- Department of Obstetrics and Gynaecology, University of Zambia School of Medicine, Lusaka, Zambia
| | - Sungano Mharakurwa
- Faculty of Health Sciences, Africa University, Mutare, Zimbabwe.,Department of Medical Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Mike Chaponda
- Department of Clinical Sciences, Tropical Diseases Research Centre, Ndola, Zambia
| | - James Chipeta
- Department of Paediatrics and Child Health, University of Zambia School of Medicine, Lusaka, Zambia
| | - Daniel Chandramohan
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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19
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Guo S, He L, Tisch DJ, Kazura J, Mharakurwa S, Mahanta J, Herrera S, Wang B, Cui L. Pilot testing of dipsticks as point-of-care assays for rapid diagnosis of poor-quality artemisinin drugs in endemic settings. Trop Med Health 2016; 44:15. [PMID: 27433134 PMCID: PMC4940968 DOI: 10.1186/s41182-016-0015-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 04/15/2016] [Indexed: 12/03/2022] Open
Abstract
Background Good-quality artemisinin drugs are essential for malaria treatment, but increasing prevalence of poor-quality artemisinin drugs in many endemic countries hinders effective management of malaria cases. Methods To develop a point-of-care assay for rapid identification of counterfeit and substandard artemisinin drugs for resource-limited areas, we used specific monoclonal antibodies against artesunate and artemether, and developed prototypes of lateral flow dipstick assays. In this pilot test, we evaluated the feasibility of these dipsticks under different endemic settings and their performance in the hands of untrained personnel. Results The results showed that the dipstick tests can be successfully performed by different investigators with the included instruction sheet. None of the artemether and artesunate drugs collected from public pharmacies in different endemic countries failed the test. Conclusion It is possible that the simple dipstick assays, with future optimization of test conditions and sensitivity, can be used as a qualitative and semi-quantitative assay for rapid screening of counterfeit artemisinin drugs in endemic settings.
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Affiliation(s)
- Suqin Guo
- College of Agronomy and Biotechnology, China Agricultural University, Beijing, China
| | - Lishan He
- College of Agronomy and Biotechnology, China Agricultural University, Beijing, China.,Present address: College of Agronomy, Guangxi University, 530004 Nanning, China
| | - Daniel J Tisch
- Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, OH USA
| | - James Kazura
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH USA
| | - Sungano Mharakurwa
- Malaria Research Department, Macha Research Trust, Johns Hopkins Malaria Research Institute, Choma, Zambia
| | - Jagadish Mahanta
- Regional Medical Research Centre (NE), Dibrugarh, 786001 Assam India
| | - Sócrates Herrera
- Caucaseco Scientific Research Center and Malaria Vaccine and Drug Development Center, Cali, Colombia
| | - Baomin Wang
- College of Agronomy and Biotechnology, China Agricultural University, Beijing, China
| | - Liwang Cui
- Department of Entomology, Pennsylvania State University, University Park, PA 16802 USA
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20
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Kanyangarara M, Mamini E, Mharakurwa S, Munyati S, Gwanzura L, Kobayashi T, Shields T, Mullany LC, Mutambu S, Mason PR, Curriero FC, Moss WJ. Individual- and Household-Level Risk Factors Associated with Malaria in Mutasa District, Zimbabwe: A Serial Cross-Sectional Study. Am J Trop Med Hyg 2016; 95:133-40. [PMID: 27114289 DOI: 10.4269/ajtmh.15-0847] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 01/31/2016] [Indexed: 11/07/2022] Open
Abstract
Malaria constitutes a major public health problem in Zimbabwe, particularly in the north and east bordering Zambia and Mozambique. In Manicaland Province in eastern Zimbabwe, malaria transmission is seasonal and unstable. Over the past decade, Manicaland Province has reported increased malaria transmission due to limited funding, drug resistance and insecticide resistance. The aim of this study was to identify risk factors at the individual and household levels to better understand the epidemiology of malaria and guide malaria control strategies in eastern Zimbabwe. Between October 2012 and September 2014, individual demographic data and household characteristics were collected from cross-sectional surveys of 1,116 individuals residing in 316 households in Mutasa District, one of the worst affected districts. Factors associated with malaria, measured by rapid diagnostic test (RDT), were identified through multilevel logistic regression models. A total of 74 participants were RDT positive. Sleeping under a bed net had a protective effect against malaria despite pyrethroid resistance in the mosquito vector. Multivariate analysis showed that malaria risk was higher among individuals younger than 25 years, residing in households located at a lower household density and in closer proximity to the Mozambique border. The risk factors identified need to be considered in targeting malaria control interventions to reduce host-vector interactions.
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Affiliation(s)
- Mufaro Kanyangarara
- Department of International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland.
| | - Edmore Mamini
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | | | - Shungu Munyati
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Lovemore Gwanzura
- Department of Medical Laboratory Sciences, College of Health Sciences, University of Zimbabwe, Harare, Zimbabwe
| | - Tamaki Kobayashi
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland
| | - Timothy Shields
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland
| | - Luke C Mullany
- Department of International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland
| | - Susan Mutambu
- National Institute of Health Research, Harare, Zimbabwe
| | - Peter R Mason
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Frank C Curriero
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland
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21
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Kanyangarara M, Mamini E, Mharakurwa S, Munyati S, Gwanzura L, Kobayashi T, Shields T, Mullany LC, Mutambu S, Mason PR, Curriero FC, Moss WJ. High-Resolution Plasmodium falciparum Malaria Risk Mapping in Mutasa District, Zimbabwe: Implications for Regaining Control. Am J Trop Med Hyg 2016; 95:141-7. [PMID: 27114294 DOI: 10.4269/ajtmh.15-0865] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 01/31/2016] [Indexed: 11/07/2022] Open
Abstract
In Zimbabwe, more than half of malaria cases are concentrated in Manicaland Province, where seasonal malaria epidemics occur despite intensified control strategies. The objectives of this study were to develop a prediction model based on environmental risk factors and obtain seasonal malaria risk maps for Mutasa District, one of the worst affected districts in Manicaland Province. From October 2012 to September 2015, 483 households were surveyed, and 104 individuals residing within 69 households had positive rapid diagnostic test results. Logistic regression was used to model the probability of household positivity as a function of the environmental covariates extracted from high-resolution remote sensing data sources. Model predictions and prediction standard errors were generated for the rainy and dry seasons. The resulting maps predicted elevated risk during the rainy season, particularly in low-lying areas bordering Mozambique. In contrast, the risk of malaria was low across the study area during the dry season with foci of malaria risk scattered along the northern and western peripheries of the study area. These findings underscore the need for strong cross-border malaria control initiatives to complement country-specific interventions.
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Affiliation(s)
- Mufaro Kanyangarara
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland.
| | - Edmore Mamini
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | | | - Shungu Munyati
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Lovemore Gwanzura
- Department of Medical Laboratory Sciences, College of Health Sciences, University of Zimbabwe, Harare, Zimbabwe
| | - Tamaki Kobayashi
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
| | - Timothy Shields
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
| | - Luke C Mullany
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
| | - Susan Mutambu
- National Institute of Health Research, Harare, Zimbabwe
| | - Peter R Mason
- Biomedical Research and Training Institute, Harare, Zimbabwe
| | - Frank C Curriero
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
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Kanyangarara M, Mamini E, Mharakurwa S, Munyati S, Gwanzura L, Kobayashi T, Shields T, Mullany LC, Mutambu S, Mason PR, Curriero FC, Moss WJ. Reduction in Malaria Incidence following Indoor Residual Spraying with Actellic 300 CS in a Setting with Pyrethroid Resistance: Mutasa District, Zimbabwe. PLoS One 2016; 11:e0151971. [PMID: 27018893 PMCID: PMC4809594 DOI: 10.1371/journal.pone.0151971] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 03/07/2016] [Indexed: 12/04/2022] Open
Abstract
Background More than half of malaria cases in Zimbabwe are concentrated in Manicaland Province, where seasonal malaria epidemics occur despite intensified control strategies. Recently, high levels of pyrethroid and carbamate resistance were detected in Anopheles funestus, the major malaria vector in eastern Zimbabwe. In response, a single round of indoor residual spraying (IRS) using pirimiphos-methyl (an organophosphate) was implemented in four high burden districts of Manicaland Province from November 1, 2014 to December 19, 2014. The objective of this study was to evaluate the effect of this programmatic switch in insecticides on malaria morbidity reported from health care facilities in Mutasa District, one of the worst affected districts in Manicaland Province. Methods The number of weekly malaria cases for each health facility 24 months prior to the 2014 IRS campaign and in the subsequent high transmission season were obtained from passive case surveillance. Environmental variables were extracted from remote-sensing data sources and linked to each health care facility. Negative binomial regression was used to model the weekly number of malaria cases, adjusted for seasonality and environmental variables. Results From December 2012 to May 2015, 124,206 malaria cases were reported from 42 health care facilities in Mutasa District. Based on a higher burden of malaria, 20 out of 31 municipal wards were sprayed in the district. Overall, 87.3% of target structures were sprayed and 92.1% of the target population protected. During the 6 months after the 2014 IRS campaign, a period when transmission would have otherwise peaked, the incidence of malaria was 38% lower than the preceding 24 months at health facilities in the sprayed wards. Conclusions Pirimiphos-methyl had a measurable impact on malaria incidence and is an effective insecticide for the control of An. funestus in eastern Zimbabwe.
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Affiliation(s)
- Mufaro Kanyangarara
- Department of International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- * E-mail:
| | - Edmore Mamini
- Biomedical Research Training Institute, Harare, Zimbabwe
| | | | - Shungu Munyati
- Biomedical Research Training Institute, Harare, Zimbabwe
| | - Lovemore Gwanzura
- Biomedical Research Training Institute, Harare, Zimbabwe
- Department of Medical Laboratory Sciences, University of Zimbabwe College of Health Sciences, Harare, Zimbabwe
| | - Tamaki Kobayashi
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Timothy Shields
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Luke C. Mullany
- Department of International Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Susan Mutambu
- National Institute of Health Research, Harare, Zimbabwe
| | - Peter R. Mason
- Biomedical Research Training Institute, Harare, Zimbabwe
| | - Frank C. Curriero
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - William J. Moss
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
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Chaponda EB, Chandramohan D, Michelo C, Mharakurwa S, Chipeta J, Chico RM. High burden of malaria infection in pregnant women in a rural district of Zambia: a cross-sectional study. Malar J 2015; 14:380. [PMID: 26423819 PMCID: PMC4590700 DOI: 10.1186/s12936-015-0866-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 08/22/2015] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Malaria continues to be a major health problem in low-income countries. Consequently, malaria control remains a public health priority in endemic countries such as Zambia. Pregnant women and children under 5 years of age are among groups at high risk of malaria infection. Malaria infection is associated with adverse birth outcomes that affect the mother, foetus, and infant. Infection with HIV has been shown to increase the risk of malaria infection in pregnancy. The prevalence and the predictors of malaria infection among pregnant women resident in the Nchelenge District of northern Zambia were investigated. METHODS Between November 2013 and April 2014, pregnant women in the catchment areas of two health centres were recruited during their first antenatal care visit. HIV testing was conducted as part of routine care. In addition, blood samples were collected from 1086 participants and tested for malaria infection using standard microscopy and polymerase chain reaction (PCR) techniques specific for Plasmodium falciparum. Multivariate logistic regression were conducted to examine the predictors of malaria infection. RESULTS The prevalence of malaria identified by microscopy was 31.8 % (95 % confidence intervals [CI], 29.0-34.5; N = 1079) and by PCR was 57.8 % (95 % CI, 54.9-60.8; N = 1074). HIV infection was 13.2 % among women on their first antenatal visit; the prevalence of malaria detected by PCR among HIV-uninfected and HIV-infected women was 56.7 % (531/936) and 65.2 % (90/138), respectively. In the final model, the risk of malaria infection was 81 % higher among pregnant women recruited from Nchelenge health centre compared to those attending the Kashikishi health centre (adjusted odds ratio = 1.81; 95 % CI, 1.38-2.37, P < 0.001), and HIV-infected women across health centres had a 46 % greater risk of malaria infection compared to HIV-uninfected women (adjusted odds ratio = 1.46; 95 %, 1.00-2.13, P = 0.045). CONCLUSION High burden of malaria detected by PCR in these pregnant women suggests that past prevention efforts have had limited effect. To reduce this burden of malaria sustainably, there is clear need to strengthen existing interventions and, possibly, to change approaches so as to improve targeting of groups most affected by malaria.
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Affiliation(s)
- Enesia Banda Chaponda
- Department of Biological Sciences, University of Zambia, Lusaka, Zambia. .,Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
| | - Daniel Chandramohan
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
| | - Charles Michelo
- Department of Public Health, School of Medicine, University of Zambia, Lusaka, Zambia.
| | - Sungano Mharakurwa
- Africa University, Mutare, Zimbabwe. .,Johns Hopkins Bloomberg School of Public Health, Baltimore, USA.
| | - James Chipeta
- Department of Paediatrics and Child Health, University of Zambia School of Medicine, P.O. Box 50110, Lusaka, Zambia.
| | - R Matthew Chico
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
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Cui L, Mharakurwa S, Ndiaye D, Rathod PK, Rosenthal PJ. Antimalarial Drug Resistance: Literature Review and Activities and Findings of the ICEMR Network. Am J Trop Med Hyg 2015; 93:57-68. [PMID: 26259943 PMCID: PMC4574275 DOI: 10.4269/ajtmh.15-0007] [Citation(s) in RCA: 180] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 04/27/2015] [Indexed: 11/07/2022] Open
Abstract
Antimalarial drugs are key tools for the control and elimination of malaria. Recent decreases in the global malaria burden are likely due, in part, to the deployment of artemisinin-based combination therapies. Therefore, the emergence and potential spread of artemisinin-resistant parasites in southeast Asia and changes in sensitivities to artemisinin partner drugs have raised concerns. In recognition of this urgent threat, the International Centers of Excellence for Malaria Research (ICEMRs) are closely monitoring antimalarial drug efficacy and studying the mechanisms underlying drug resistance. At multiple sentinel sites of the global ICEMR network, research activities include clinical studies to track the efficacies of antimalarial drugs, ex vivo/in vitro assays to measure drug susceptibilities of parasite isolates, and characterization of resistance-mediating parasite polymorphisms. Taken together, these efforts offer an increasingly comprehensive assessment of the efficacies of antimalarial therapies, and enable us to predict the emergence of drug resistance and to guide local antimalarial drug policies. Here we briefly review worldwide antimalarial drug resistance concerns, summarize research activities of the ICEMRs related to drug resistance, and assess the global impacts of the ICEMR programs.
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Affiliation(s)
- Liwang Cui
- *Address correspondence to Liwang Cui, Department of Entomology, Pennsylvania State University, 501 ASI Building, University Park, PA 16802, E-mail: or Philip J. Rosenthal, Department of Medicine, Box 0811, University of California, San Francisco, CA 94110. E-mail:
| | | | | | | | - Philip J. Rosenthal
- *Address correspondence to Liwang Cui, Department of Entomology, Pennsylvania State University, 501 ASI Building, University Park, PA 16802, E-mail: or Philip J. Rosenthal, Department of Medicine, Box 0811, University of California, San Francisco, CA 94110. E-mail:
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25
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Siame MNP, Mharakurwa S, Chipeta J, Thuma P, Michelo C. High prevalence of dhfr and dhps molecular markers in Plasmodium falciparum in pregnant women of Nchelenge district, Northern Zambia. Malar J 2015; 14:190. [PMID: 25943379 PMCID: PMC4425916 DOI: 10.1186/s12936-015-0676-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 04/04/2015] [Indexed: 11/10/2022] Open
Abstract
Background Sulphadoxine-pyrimethamine (SP) is the recommended drug for intermittent preventive treatment in pregnancy (IPTp) in most African countries, including Zambia. However, malaria is still one of the leading causes of morbidity and mortality in pregnant women despite reports of greater than 50% of women taking at least two doses of SP in IPTp. Studies have shown that resistance to SP is associated with mutations in the dhfr and dhps gene of Plasmodium falciparum. This study examined the prevalence of dhfr and dhps polymorphisms in P. falciparum found in pregnant women of Nchelenge district. Method This cross-sectional study was conducted in 2013 in Nchelenge, a holoendemic area with malaria prevalence estimated at 50% throughout the year. Three rural health centres were randomly selected and a census survey carried out at each health centre. A questionnaire was administered and malaria testing done using RDT and microscopy, with collection of a dried blood spot. A chelex extraction was done to extract parasite DNA from dried blood spots followed by nested PCR and enzyme restriction digestion. Results Of the enrolled participants (n = 375), the median age of the women was 23. The prevalence of malaria by PCR was 22%. The PCR positive samples examined (n = 72) showed a high prevalence of dhfr triple (Asn-108 + Arg-59 + Ile-59) mutant (68%) and dhps double (Gly -437 + Glu-540) mutant (21%). The quintuple haplotype was found in 17% with 2 samples with an additional Gly-581mutation. In addition 6% mutations at Val-16 were found and none found at Thr-108 respectively, these both confer resistance to cycloguanil. Multivariate analysis showed that there was an association between malaria and women aged 30-34 years old p < 0.05(AOR: 0.36) at 95% CI. Conclusion This study showed a high number of mutations in the dhfr and dhps genes. The high malaria endemicity in the general population of this area may have contributed to the high prevalence of resistant parasites in pregnant women, suggesting a need to examine the efficacy of SP given that it is the only approved drug for IPTp in Zambia.
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Affiliation(s)
- Mwiche N P Siame
- Department of Public health, University of Zambia, School of Medicine, Lusaka, Zambia. .,Macha Research Trust, Choma, Zambia.
| | | | - James Chipeta
- Department of Public health, University of Zambia, School of Medicine, Lusaka, Zambia.
| | | | - Charles Michelo
- Department of Public health, University of Zambia, School of Medicine, Lusaka, Zambia.
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Laban NM, Kobayashi T, Hamapumbu H, Sullivan D, Mharakurwa S, Thuma PE, Shiff CJ, Moss WJ. Comparison of a PfHRP2-based rapid diagnostic test and PCR for malaria in a low prevalence setting in rural southern Zambia: implications for elimination. Malar J 2015; 14:25. [PMID: 25888818 PMCID: PMC4340619 DOI: 10.1186/s12936-015-0544-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 01/05/2015] [Indexed: 12/01/2022] Open
Abstract
Background Rapid diagnostic tests (RDTs) detecting histidine-rich protein 2 (PfHRP2) antigen are used to identify individuals with Plasmodium falciparum infection even in low transmission settings seeking to achieve elimination. However, these RDTs lack sensitivity to detect low-density infections, produce false negatives for P. falciparum strains lacking pfhrp2 gene and do not detect species other than P. falciparum. Methods Results of a PfHRP2-based RDT and Plasmodium nested PCR were compared in a region of declining malaria transmission in southern Zambia using samples from community-based, cross-sectional surveys from 2008 to 2012. Participants were tested with a PfHRP2-based RDT and a finger prick blood sample was spotted onto filter paper for PCR analysis and used to prepare blood smears for microscopy. Species-specific, real-time, quantitative PCR (q-PCR) was performed on samples that tested positive either by microscopy, RDT or nested PCR. Results Of 3,292 total participants enrolled, 12 (0.4%) tested positive by microscopy and 42 (1.3%) by RDT. Of 3,213 (98%) samples tested by nested PCR, 57 (1.8%) were positive, resulting in 87 participants positive by at least one of the three tests. Of these, 61 tested positive for P. falciparum by q-PCR with copy numbers ≤ 2 x 103 copies/μL, 5 were positive for both P. falciparum and Plasmodium malariae and 2 were positive for P. malariae alone. RDT detected 32 (53%) of P. falciparum positives, failing to detect three of the dual infections with P. malariae. Among 2,975 participants enrolled during a low transmission period between 2009 and 2012, sensitivity of the PfHRP2-based RDT compared to nested PCR was only 17%, with specificity of >99%. The pfhrp gene was detected in 80% of P. falciparum positives; however, comparison of copy number between RDT negative and RDT positive samples suggested that RDT negatives resulted from low parasitaemia and not pfhrp2 gene deletion. Conclusions Low-density P. falciparum infections not identified by currently used PfHRP2-based RDTs and the inability to detect non-falciparum malaria will hinder progress to further reduce malaria in low transmission settings of Zambia. More sensitive and specific diagnostic tests will likely be necessary to identify parasite reservoirs and achieve malaria elimination. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0544-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Tamaki Kobayashi
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
| | | | - David Sullivan
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
| | - Sungano Mharakurwa
- Macha Research Trust, Choma, Zambia. .,W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
| | | | - Clive J Shiff
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
| | - William J Moss
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
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Comfort AB, van Dijk JH, Mharakurwa S, Stillman K, Johns B, Hathi P, Korde S, Craig AS, Nachbar N, Derriennic Y, Gabert R, Thuma PE. Association between malaria control and paediatric blood transfusions in rural Zambia: an interrupted time-series analysis. Malar J 2014; 13:383. [PMID: 25261276 PMCID: PMC4190292 DOI: 10.1186/1475-2875-13-383] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 09/20/2014] [Indexed: 11/15/2022] Open
Abstract
Background Blood transfusions can reduce mortality among children with severe malarial anaemia, but there is limited evidence quantifying the relationship between paediatric malaria and blood transfusions. This study explores the extent to which the use of paediatric blood transfusions is affected by the number of paediatric malaria visits and admissions. It assesses whether the scale-up of malaria control interventions in a facility catchment area explains the use of paediatric blood transfusions. Methods The study was conducted at a referral hospital for 13 rural health centres in rural Zambia. Data were used from facility and patient records covering all paediatric malaria admissions from 2000 to 2008. An interrupted time series analysis using an autoregression-moving-average model was conducted to assess the relationship between paediatric malaria outpatient visits and admissions and the use of paediatric blood transfusions. Further investigation explored whether the use of paediatric blood transfusions over time was consistent with the roll out of malaria control interventions in the hospital catchment area. Results For each additional paediatric malaria outpatient visit, there were 0.07 additional paediatric blood transfusions (95% CI 0.01-0.13; p < 0.05). For each additional paediatric admission for severe malarial anaemia, there were 1.09 additional paediatric blood transfusions (95% CI 0.95-1.23; p < 0.01). There were 19.1 fewer paediatric blood transfusions per month during the 2004–2006 malaria control period (95% CI 12.1-26.0; p < 0.01), a 50% reduction compared to the preceding period when malaria control was relatively limited. During the 2007–2008 malaria control period, there were 27.5 fewer paediatric blood transfusions per month (95% CI 14.6-40.3; p < 0.01), representing a 72% decline compared to the period with limited malaria control. Conclusions Paediatric admissions for severe malarial anaemia largely explain total use of paediatric blood transfusions. The reduction in paediatric blood transfusions is consistent with the timing of the malaria control interventions. Malaria control seems to influence the use of paediatric blood transfusions by reducing the number of paediatric admissions for severe malarial anaemia. Reduced use of blood transfusions could benefit other areas of the health system through greater blood availability, particularly where supply is limited.
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Affiliation(s)
- Alison B Comfort
- Abt Associates, International Health Division, Cambridge, MA, USA.
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Mharakurwa S, Daniels R, Scott A, Wirth DF, Thuma P, Volkman SK. Pre-amplification methods for tracking low-grade Plasmodium falciparum populations during scaled-up interventions in Southern Zambia. Malar J 2014; 13:89. [PMID: 24618119 PMCID: PMC4007587 DOI: 10.1186/1475-2875-13-89] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 03/03/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria is receding in many endemic countries with intervention scale -up against the disease. However, this resilient scourge may persist in low-grade submicroscopic infections among semi-immune members of the population, and be poised for possible resurgence, creating challenges for detection and assessment of intervention impact. Parasite genotyping methods, such as the molecular barcode, can identify specific malaria parasite types being transmitted and allow tracking and evaluation of parasite population structure changes as interventions are applied. This current study demonstrates application of pre-amplification methods for successful detection and genotyping of residual Plasmodium falciparum infections during a dramatic malarial decline. METHODS The study was a prospective cross-sectional design and based on a 2,000 sq km vicinity of Macha Mission Hospital in southern Zambia. Willing and predominantly asymptomatic residents of all ages were screened for malaria by microscopy during the 2005 and 2008 transmission seasons, with simultaneous collection of dried blood spots (DBS) on filter paper, and extraction of Plasmodium falciparum DNA was performed. Plasmodium falciparum infections were genotyped using a 24 SNP-based molecular barcode assay using real-time PCR. Submicroscopic parasitaemia samples were subjected to pre-amplification using TaqMan PreAmp Master Mix following the manufacturer's instructions before SNP barcode analysis. RESULTS There was a dramatic decline of malaria between 2005 and 2008, and the geometric mean parasite density (95% CI) fell from 704/μL (390-1,271) in 2005 to 39/μL (23-68) in 2008, culminating in a large proportion of submicroscopic infections of which 90% failed to yield ample DNA for standard molecular characterization among 2008 samples. Pre-amplification enabled successful detection and genotyping of 74% of these low-grade reservoir infections, overall, compared to 54% that were detectable before pre-amplification (p <0.0005, n = 84). Furthermore, nine samples negative for parasites by microscopy and standard quantitative PCR amplification were positive after pre-amplification. CONCLUSIONS Pre-amplification allows analysis of an otherwise undetectable parasite population and may be instrumental for parasites identification, tracking and assessing the impact of interventions on parasite populations during malaria control and elimination programmes when parasitaemia is expected to decline to submicroscopic levels.
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Mharakurwa S, Sialumano M, Liu K, Scott A, Thuma P. Selection for chloroquine-sensitive Plasmodium falciparum by wild Anopheles arabiensis in Southern Zambia. Malar J 2013; 12:453. [PMID: 24354640 PMCID: PMC3878239 DOI: 10.1186/1475-2875-12-453] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 12/17/2013] [Indexed: 11/20/2022] Open
Abstract
Background The emergence of parasite drug resistance, especially Plasmodium falciparum, persists as a major obstacle for malaria control and elimination. To develop effective public health containment strategies, a clear understanding of factors that govern the emergence and spread of resistant parasites in the field is important. The current study documents selection for chloroquine-sensitive malaria parasites by wild Anopheles arabiensis in southern Zambia. Methods In a 2,000-sq km region, mosquitoes were collected from human sleeping rooms using pyrethrum spray catches during the 2006 malaria transmission season. After morphological examination and molecular confirmation, vector mosquitoes were dissected to separate head and thorax from the abdominal section, followed by PCR screening for P. falciparum infection. Human residents of all ages were tested for P. falciparum parasitaemia by microscopy and PCR. Plasmodium falciparum infections were genotyped at the chloroquine resistance-conferring amino acid codon 76 of the PfCRT gene, using PCR and restriction enzyme digestion. Results In the human population there was nearly 90% prevalence of the chloroquine-resistant PfCRT K76T mutant, with no significant differences in polymorphism among smear-positive and smear-negative (submicroscopic) infections (p = 0.323, n = 128). However, infections in both abdominal and salivary gland phases of the An. arabiensis vector exhibited wild type K76-bearing parasites with up to 9X higher odds (OR (95% CI): 9 (3.7-20.2), p < 0.0005, n = 125), despite having been acquired from humans within a few weeks. Conclusions Anopheles arabiensis selects for wild-type K76-bearing P. falciparum during both abdominal and salivary gland phases of parasite development. The rapid vectorial selection, also recently seen with antifolate resistance, is evidence for parasite fitness cost in the mosquito, and may underpin regional heterogeneity in the emergence, spread and waning of drug resistance. Understanding the nature and direction of vector selection could be instrumental for rational curtailment of the spread of drug resistance in integrated malaria control and elimination programmes.
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Comfort AB, van Dijk JH, Mharakurwa S, Stillman K, Gabert R, Korde S, Nachbar N, Derriennic Y, Musau S, Hamazakaza P, Zyambo KD, Zyongwe NM, Hamainza B, Thuma PE. Hospitalizations and costs incurred at the facility level after scale-up of malaria control: pre-post comparisons from two hospitals in Zambia. Am J Trop Med Hyg 2013; 90:20-32. [PMID: 24218409 PMCID: PMC3886421 DOI: 10.4269/ajtmh.13-0019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
There is little evidence on the impact of malaria control on the health system, particularly at the facility level. Using retrospective, longitudinal facility-level and patient record data from two hospitals in Zambia, we report a pre-post comparison of hospital admissions and outpatient visits for malaria and estimated costs incurred for malaria admissions before and after malaria control scale-up. The results show a substantial reduction in inpatient admissions and outpatient visits for malaria at both hospitals after the scale-up, and malaria cases accounted for a smaller proportion of total hospital visits over time. Hospital spending on malaria admissions also decreased. In one hospital, malaria accounted for 11% of total hospital spending before large-scale malaria control compared with < 1% after malaria control. The findings demonstrate that facility-level resources are freed up as malaria is controlled, potentially making these resources available for other diseases and conditions.
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Affiliation(s)
- Alison B. Comfort
- *Address correspondence to Alison B. Comfort, Abt Associates, 55 Wheeler St., Cambridge, MA 02138. E-mail:
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Searle KM, Shields T, Hamapumbu H, Kobayashi T, Mharakurwa S, Thuma PE, Smith DL, Glass G, Moss WJ. Efficiency of household reactive case detection for malaria in rural Southern Zambia: simulations based on cross-sectional surveys from two epidemiological settings. PLoS One 2013; 8:e70972. [PMID: 23940677 PMCID: PMC3735521 DOI: 10.1371/journal.pone.0070972] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2013] [Accepted: 06/27/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Case detection and treatment are critical to malaria control and elimination as infected individuals who do not seek medical care can serve as persistent reservoirs for transmission. METHODS Household malaria surveys were conducted in two study areas within Southern Province, Zambia in 2007 and 2008. Cross-sectional surveys were conducted approximately five times throughout the year in each of the two study areas. During study visits, adults and caretakers of children were administered a questionnaire and a blood sample was obtained for a rapid diagnostic test (RDT) for malaria. These data were used to estimate the proportions of individuals with malaria potentially identified through passive case detection at health care facilities and those potentially identified through reactive case finding. Simulations were performed to extrapolate data from sampled to non-sampled households. Radii of increasing size surrounding households with an index case were examined to determine the proportion of households with an infected individual that would be identified through reactive case detection. RESULTS In the 2007 high transmission setting, with a parasite prevalence of 23%, screening neighboring households within 500 meters of an index case could have identified 89% of all households with an RDT positive resident and 90% of all RDT positive individuals. In the 2008 low transmission setting, with a parasite prevalence of 8%, screening neighboring households within 500 meters of a household with an index case could have identified 77% of all households with an RDT positive resident and 76% of all RDT positive individuals. CONCLUSIONS Testing and treating individuals residing within a defined radius from an index case has the potential to be an effective strategy to identify and treat a large proportion of infected individuals who do not seek medical care, although the efficiency of this strategy is likely to decrease with declining parasite prevalence.
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Affiliation(s)
- Kelly M. Searle
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Timothy Shields
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | | | - Tamaki Kobayashi
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Sungano Mharakurwa
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
- Macha Research Trust, Choma, Zambia
| | | | - David L. Smith
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Gregory Glass
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - William J. Moss
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
- * E-mail:
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Mharakurwa S, Mutambu SL, Mberikunashe J, Thuma PE, Moss WJ, Mason PR. Changes in the burden of malaria following scale up of malaria control interventions in Mutasa District, Zimbabwe. Malar J 2013; 12:223. [PMID: 23815862 PMCID: PMC3703256 DOI: 10.1186/1475-2875-12-223] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 06/24/2013] [Indexed: 11/12/2022] Open
Abstract
Background To better understand trends in the burden of malaria and their temporal relationship to control activities, a survey was conducted to assess reported cases of malaria and malaria control activities in Mutasa District, Zimbabwe. Methods Data on reported malaria cases were abstracted from available records at all three district hospitals, three rural hospitals and 25 rural health clinics in Mutasa District from 2003 to 2011. Results Malaria control interventions were scaled up through the support of the Roll Back Malaria Partnership, the Global Fund to Fight AIDS, Tuberculosis and Malaria, and The President’s Malaria Initiative. The recommended first-line treatment regimen changed from chloroquine or a combination of chloroquine plus sulphadoxine/pyrimethamine to artemisinin-based combination therapy, the latter adopted by 70%, 95% and 100% of health clinics by 2008, 2009 and 2010, respectively. Diagnostic capacity improved, with rapid diagnostic tests (RDTs) available in all health clinics by 2008. Vector control consisted of indoor residual spraying and distribution of long-lasting insecticidal nets. The number of reported malaria cases initially increased from levels in 2003 to a peak in 2008 but then declined 39% from 2008 to 2010. The proportion of suspected cases of malaria in older children and adults remained high, ranging from 75% to 80%. From 2008 to 2010, the number of RDT positive cases of malaria decreased 35% but the decrease was greater for children younger than five years of age (60%) compared to older children and adults (26%). Conclusions The burden of malaria in Mutasa District decreased following the scale up of malaria control interventions. However, the persistent high number of cases in older children and adults highlights the need for strategies to identify locally effective control measures that target all age groups.
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Affiliation(s)
- Sungano Mharakurwa
- Johns Hopkins Malaria Research Institute, Bloomberg School of Public Health, Johns Hopkins University, 615 North Wolfe Street, Baltimore, MD 21205, USA
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Ongagna-Yhombi SY, Corstjens P, Geva E, Abrams WR, Barber CA, Malamud D, Mharakurwa S. Improved assay to detect Plasmodium falciparum using an uninterrupted, semi-nested PCR and quantitative lateral flow analysis. Malar J 2013; 12:74. [PMID: 23433252 PMCID: PMC3605351 DOI: 10.1186/1475-2875-12-74] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Accepted: 02/18/2013] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND A rapid, non-invasive, and inexpensive point-of-care (POC) diagnostic for malaria followed by therapeutic intervention would improve the ability to control infection in endemic areas. METHODS A semi-nested PCR amplification protocol is described for quantitative detection of Plasmodium falciparum and is compared to a traditional nested PCR. The approach uses primers that target the P. falciparum dihydrofolate reductase gene. RESULTS This study demonstrates that it is possible to perform an uninterrupted, asymmetric, semi-nested PCR assay with reduced assay time to detect P. falciparum without compromising the sensitivity and specificity of the assay using saliva as a testing matrix. CONCLUSIONS The development of this PCR allows nucleic acid amplification without the need to transfer amplicon from the first PCR step to a second reaction tube with nested primers, thus reducing both the chance of contamination and the time for analysis to < two hours. Analysis of the PCR amplicon yield was adapted to lateral flow detection using the quantitative up-converting phosphor (UCP) reporter technology. This approach provides a basis for migration of the assay to a POC microfluidic format. In addition the assay was successfully evaluated with oral samples. Oral fluid collection provides a simple non-invasive method to collect clinical samples.
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Musapa M, Kumwenda T, Mkulama M, Chishimba S, Norris DE, Thuma PE, Mharakurwa S. A simple Chelex protocol for DNA extraction from Anopheles spp. J Vis Exp 2013:3281. [PMID: 23328684 PMCID: PMC3658367 DOI: 10.3791/3281] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Endemic countries are increasingly adopting molecular tools for efficient typing, identification and surveillance against malaria parasites and vector mosquitoes, as an integral part of their control programs1,2,3,4,5. For sustainable establishment of these accurate approaches in operations research to strengthen malaria control and elimination efforts, simple and affordable methods, with parsimonious reagent and equipment requirements are essential6,7,8. Here we present a simple Chelex-based technique for extracting malaria parasite and vector DNA from field collected mosquito specimens. We morphologically identified 72 Anopheles gambiae sl. from 156 mosquitoes captured by pyrethrum spray catches in sleeping rooms of households within a 2,000 km2 vicinity of the Malaria Institute at Macha. After dissection to separate the head and thorax from the abdomen for all 72 Anopheles gambiae sl. mosquitoes, the two sections were individually placed in 1.5 ml microcentrifuge tubes and submerged in 20 μl of deionized water. Using a sterile pipette tip, each mosquito section was separately homogenized to a uniform suspension in the deionized water. Of the ensuing homogenate from each mosquito section, 10 μl was retained while the other 10 μl was transferred to a separate autoclaved 1.5 ml tube. The separate aliquots were subjected to DNA extraction by either the simplified Chelex or the standard salting out extraction protocol9,10. The salting out protocol is so-called and widely used because it employs high salt concentrations in lieu of hazardous organic solvents (such as phenol and chloroform) for the protein precipitation step during DNA extraction9. Extracts were used as templates for PCR amplification using primers targeting arthropod mitochondrial nicotinamide adenine dinucleotide dehydrogenase (NADH) subunit 4 gene (ND4) to check DNA quality11, a PCR for identification of Anopheles gambiae sibling species10 and a nested PCR for typing of Plasmodium falciparum infection12. Comparison using DNA quality (ND4) PCR showed 93% sensitivity and 82% specificity for the Chelex approach relative to the established salting out protocol. Corresponding values of sensitivity and specificity were 100% and 78%, respectively, using sibling species identification PCR and 92% and 80%, respectively for P. falciparum detection PCR. There were no significant differences in proportion of samples giving amplicon signal with the Chelex or the regular salting out protocol across all three PCR applications. The Chelex approach required three simple reagents and 37 min to complete, while the salting out protocol entailed 10 different reagents and 2 hr and 47 min' processing time, including an overnight step. Our results show that the Chelex method is comparable to the existing salting out extraction and can be substituted as a simple and sustainable approach in resource-limited settings where a constant reagent supply chain is often difficult to maintain.
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Kobayashi T, Chishimba S, Shields T, Hamapumbu H, Mharakurwa S, Thuma PE, Glass G, Moss WJ. Temporal and spatial patterns of serologic responses to Plasmodium falciparum antigens in a region of declining malaria transmission in southern Zambia. Malar J 2012; 11:438. [PMID: 23276228 PMCID: PMC3544625 DOI: 10.1186/1475-2875-11-438] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 12/12/2012] [Indexed: 12/04/2022] Open
Abstract
Background Critical to sustaining progress in malaria control is comprehensive surveillance to identify outbreaks and prevent resurgence. Serologic responses to Plasmodium falciparum antigens can serve as a marker of recent transmission and serosurveillance may be feasible on a large scale. Methods Satellite images were used to construct a sampling frame for the random selection of households enrolled in prospective longitudinal and cross-sectional surveys in two study areas in Southern Province, Zambia, one in 2007 and the other in 2008 and 2009. Blood was collected and stored as dried spots from participating household members. A malaria rapid diagnostic test (RDT) was used to diagnose malaria. An enzyme immunoassay (EIA) was used to detect IgG antibodies to asexual stage P. falciparum whole parasite lysate using serum eluted from dried blood spots. The expected mean annual increase in optical density (OD) value for individuals with a documented prior history of recent malaria was determined using mixed models. SatScan was used to determine the spatial clustering of households with individuals with serological evidence of recent malaria, and these households were plotted on a malaria risk map. Results RDT positivity differed markedly between the study areas and years: 28% of participants for whom serologic data were available were RDT positive in the 2007 study area, compared to 8.1% and 1.4% in the 2008 and 2009 study area, respectively. Baseline antibody levels were measured in 234 participants between April and July 2007, 435 participants between February and December 2008, and 855 participants between January and December 2009. As expected, the proportion of seropositive individuals increased with age in each year. In a subset of participants followed longitudinally, RDT positivity at the prior visit was positively correlated with an increase in EIA OD values after adjusting for age in 2007 (0.261, p = 0.003) and in 2008 (0.116, p = 0.03). RDT positivity at the concurrent visit also was associated with an increase in EIA OD value in 2007 (mean increase 0.177, p = 0.002) but not in 2008 (−0.063, p =0.50). Households comprised of individuals with serologic evidence of recent malaria overlapped areas of high malaria risk for serologic data from 2009, when parasite prevalence was lowest. Conclusions Serological surveys to whole asexual P. falciparum antigens using blood collected as dried blood spots can be used to detect temporal and spatial patterns of malaria transmission in a region of declining malaria burden, and have the potential to identify focal areas of recent transmission.
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Affiliation(s)
- Tamaki Kobayashi
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
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Stresman G, Kobayashi T, Kamanga A, Thuma PE, Mharakurwa S, Moss WJ, Shiff C. Malaria research challenges in low prevalence settings. Malar J 2012; 11:353. [PMID: 23098277 PMCID: PMC3502576 DOI: 10.1186/1475-2875-11-353] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Accepted: 10/18/2012] [Indexed: 12/29/2022] Open
Abstract
The prevalence of malaria has reduced significantly in some areas over the past decade. These reductions have made local elimination possible and the research agenda has shifted to this new priority. However, there are critical issues that arise when studying malaria in low transmission settings, particularly identifying asymptomatic infections, accurate detection of individuals with microparasitaemic infections, and achieving a sufficient sample size to have an adequately powered study. These challenges could adversely impact the study of malaria elimination if they remain unanswered.
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Affiliation(s)
- Gillian Stresman
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, UK
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Mharakurwa S, Thuma PE, Norris DE, Mulenga M, Chalwe V, Chipeta J, Munyati S, Mutambu S, Mason PR. Malaria epidemiology and control in Southern Africa. Acta Trop 2012; 121:202-6. [PMID: 21756864 DOI: 10.1016/j.actatropica.2011.06.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Revised: 06/04/2011] [Accepted: 06/26/2011] [Indexed: 11/19/2022]
Abstract
The burden of malaria has decreased dramatically within the past several years in parts of sub-Saharan Africa, following the scale-up of interventions supported by the Roll Back Malaria Partnership, the President's Malaria Initiative and other partners. It is important to appreciate that the reductions in malaria have not been uniform between and within countries, with some areas experiencing resurgence instead. Furthermore, while interventions have greatly reduced the burden of malaria in many countries, it is also recognized that the malaria decline pre-dated widespread intervention efforts, at least in some cases where data are available. This raises more questions as what other factors may have been contributing to the reduction in malaria transmission and to what extent. The International Center of Excellence for Malaria Research (ICEMR) in Southern Africa aims to better understand the underlying malaria epidemiology, vector ecology and parasite genomics using three contrasting settings of malaria transmission in Zambia and Zimbabwe: an area of successful malaria control, an area of resurgent malaria and an area where interventions have not been effective. The Southern Africa ICEMR will capitalize on the opportunity to investigate the complexities of malaria transmission while adapting to intervention and establish the evidence-base to guide effective and sustainable malaria intervention strategies. Key approaches to attain this goal for the region will include close collaboration with national malaria control programs and contribution to capacity building at the individual, institutional and national levels.
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Affiliation(s)
- Sungano Mharakurwa
- Johns Hopkins Malaria Research Institute, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA.
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Moss WJ, Norris DE, Mharakurwa S, Scott A, Mulenga M, Mason PR, Chipeta J, Thuma PE. Challenges and prospects for malaria elimination in the Southern Africa region. Acta Trop 2012; 121:207-11. [PMID: 21871864 DOI: 10.1016/j.actatropica.2011.06.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Revised: 05/18/2011] [Accepted: 06/06/2011] [Indexed: 11/30/2022]
Abstract
The burden of malaria has decreased dramatically within the past several years in parts of sub-Saharan Africa, including regions of Southern Africa. Important to effective regional malaria control in Southern Africa is the appreciation that the reductions in malaria have not been achieved uniformly, with some countries experiencing resurgence. Understanding the reasons for sustained low-level malaria transmission in the face of control efforts, why malaria control efforts have not been successful in particular epidemiological settings and the epidemiological and transmission patterns following resurgence are critical to improving further malaria control and possible elimination. The overall goal of the International Center of Excellence for Malaria Research in Southern Africa is to contribute to regional malaria control efforts that can be sustained beyond the duration of the project. This goal will be achieved through a combination of: (1) state-of-the-art research on malaria epidemiology, vector biology and the genetics of the malaria parasite in three different epidemiological settings; (2) collaborations with national malaria control programs to develop locally adapted and sustainable control strategies; and (3) training, career development and capacity building at research institutions throughout the region.
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Affiliation(s)
- William J Moss
- Johns Hopkins Malaria Research Institute, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA.
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Sutcliffe CG, Kobayashi T, Hamapumbu H, Shields T, Mharakurwa S, Thuma PE, Louis TA, Glass G, Moss WJ. Reduced risk of malaria parasitemia following household screening and treatment: a cross-sectional and longitudinal cohort study. PLoS One 2012; 7:e31396. [PMID: 22319629 PMCID: PMC3272029 DOI: 10.1371/journal.pone.0031396] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 01/06/2012] [Indexed: 11/23/2022] Open
Abstract
Background In regions of declining malaria transmission, new strategies for control are needed to reduce transmission and achieve elimination. Artemisinin-combination therapy (ACT) is active against immature gametocytes and can reduce the risk of transmission. We sought to determine whether household screening and treatment of infected individuals provides protection against infection for household members. Methodology/Principal Findings The study was conducted in two areas in Southern Province, Zambia in 2007 and 2008/2009. To determine the impact of proactive case detection, households were randomly selected either to join a longitudinal cohort, in which participants were repeatedly screened throughout the year and those infected treated with artemether-lumefantrine, or a cross-sectional survey, in which participants were visited only once. Cross-sectional surveys were conducted throughout the year. The prevalence of RDT positivity was compared between the longitudinal and cross-sectional households at baseline and during follow-up using multilevel logistic regression. In the 2007 study area, 174 and 156 participants enrolled in the cross-sectional and longitudinal groups, respectively. In the 2008/2009 study area, 917 and 234 participants enrolled in the cross-sectional and longitudinal groups, respectively. In both study areas, participants and households in the longitudinal and cross-sectional groups were similar on demographic characteristics and prevalence of RDT positivity at baseline (2007: OR = 0.97; 95% CI:0.46, 2.03 | 2008/2009: OR = 1.28; 95% CI:0.44, 3.79). After baseline, the prevalence of RDT positivity was significantly lower in longitudinal compared to cross-sectional households in both study areas (2007: OR = 0.44; 95% CI:0.20, 0.96 | 2008/2009: OR = 0.16; 95% CI:0.05, 0.55). Conclusions/Significance Proactive case detection, consisting of screening household members with an RDT and treating those positive with ACT, can reduce transmission and provide indirect protection to household members. A targeted test and treat strategy could contribute to the elimination of malaria in regions of low transmission.
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Affiliation(s)
- Catherine G. Sutcliffe
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Tamaki Kobayashi
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | | | - Timothy Shields
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Sungano Mharakurwa
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- Malaria Research Trust, Choma, Zambia
| | | | - Thomas A. Louis
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Gregory Glass
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - William J. Moss
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- * E-mail:
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Mharakurwa S, Kumwenda T, Mkulama MAP, Musapa M, Chishimba S, Shiff CJ, Sullivan DJ, Thuma PE, Liu K, Agre P. Malaria antifolate resistance with contrasting Plasmodium falciparum dihydrofolate reductase (DHFR) polymorphisms in humans and Anopheles mosquitoes. Proc Natl Acad Sci U S A 2011; 108:18796-801. [PMID: 22065788 PMCID: PMC3219121 DOI: 10.1073/pnas.1116162108] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Surveillance for drug-resistant parasites in human blood is a major effort in malaria control. Here we report contrasting antifolate resistance polymorphisms in Plasmodium falciparum when parasites in human blood were compared with parasites in Anopheles vector mosquitoes from sleeping huts in rural Zambia. DNA encoding P. falciparum dihydrofolate reductase (EC 1.5.1.3) was amplified by PCR with allele-specific restriction enzyme digestions. Markedly prevalent pyrimethamine-resistant mutants were evident in human P. falciparum infections--S108N (>90%), with N51I, C59R, and 108N+51I+59R triple mutants (30-80%). This resistance level may be from selection pressure due to decades of sulfadoxine/pyrimethamine use in the region. In contrast, cycloguanil-resistant mutants were detected in very low frequency in parasites from human blood samples-S108T (13%), with A16V and 108T+16V double mutants (∼4%). Surprisingly, pyrimethamine-resistant mutants were of very low prevalence (2-12%) in the midguts of Anopheles arabiensis vector mosquitoes, but cycloguanil-resistant mutants were highly prevalent-S108T (90%), with A16V and the 108T+16V double mutant (49-57%). Structural analysis of the dihydrofolate reductase by in silico modeling revealed a key difference in the enzyme within the NADPH binding pocket, predicting the S108N enzyme to have reduced stability but the S108T enzyme to have increased stability. We conclude that P. falciparum can bear highly host-specific drug-resistant polymorphisms, most likely reflecting different selective pressures found in humans and mosquitoes. Thus, it may be useful to sample both human and mosquito vector infections to accurately ascertain the epidemiological status of drug-resistant alleles.
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Affiliation(s)
- Sungano Mharakurwa
- The Malaria Institute at Macha, Choma, Zambia; and
- Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205
| | | | | | | | | | - Clive J. Shiff
- Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205
| | - David J. Sullivan
- Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205
| | - Philip E. Thuma
- The Malaria Institute at Macha, Choma, Zambia; and
- Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205
| | - Kun Liu
- Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205
| | - Peter Agre
- Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205
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Sutcliffe CG, Kobayashi T, Hamapumbu H, Shields T, Kamanga A, Mharakurwa S, Thuma PE, Glass G, Moss WJ. Changing individual-level risk factors for malaria with declining transmission in southern Zambia: a cross-sectional study. Malar J 2011; 10:324. [PMID: 22039751 PMCID: PMC3238226 DOI: 10.1186/1475-2875-10-324] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Accepted: 10/31/2011] [Indexed: 11/19/2022] Open
Abstract
Background Malaria elimination will require that both symptomatic- and asymptomatic-infected persons be identified and treated. However, well-characterized, individual-level risk factors for malaria may not be valid in regions with declining malaria transmission. Changes in individual-level correlates of malaria infection were evaluated over three years in a region of declining malaria transmission in southern Zambia. Methods Malaria surveys were conducted in two study areas within the catchment area of Macha Hospital, Zambia in 2007 and 2008/2009. A random sample of households was identified from a digitized satellite image of the study areas. Cross-sectional surveys were conducted approximately five times throughout the year in each of the two study areas. During study visits, adults and caretakers of children were administered questionnaires and a blood sample was obtained for a rapid diagnostic test (RDT) for malaria. Results In the 2007 study area, 330 individuals were surveyed. 40.9% of participants lived in a household with at least one insecticide-treated bed net (ITN); however, only 45.2% reported sleeping under the ITN. 23.9% of participants were RDT positive. Correlates of RDT positivity included younger age, the presence of symptoms, testing during the rainy season, using an open water source, and not sleeping under an ITN. In the 2008 study area, 435 individuals were surveyed. 77.0% of participants lived in a household with at least one ITN; however, only 56.4% reported sleeping under the ITN. 8.1% of participants were RDT positive. RDT positivity was negatively correlated with the presence of symptoms within the last two weeks but positively correlated with documented fever. In 2009, 716 individuals were surveyed in the same area as 2008. 63.7% of participants lived in a household with at least one ITN; however, only 57.7% reported sleeping under the ITN. 1.5% of participants were RDT positive. Only self-reported fever was significantly correlated with RDT positivity. Conclusions With declining malaria prevalence, few individual-level characteristics were correlated with RDT positivity. This lack of correlation with individual characteristics hampers identification of individuals infected with malaria. Strategies based on ecological or environmental risk factors may be needed to target control efforts and achieve further reductions and elimination.
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Affiliation(s)
- Catherine G Sutcliffe
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, 615 North Wolfe Street, Baltimore, MD, USA
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Davis RG, Kamanga A, Castillo-Salgado C, Chime N, Mharakurwa S, Shiff C. Early detection of malaria foci for targeted interventions in endemic southern Zambia. Malar J 2011; 10:260. [PMID: 21910855 PMCID: PMC3182978 DOI: 10.1186/1475-2875-10-260] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 09/12/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Zambia has achieved significant reductions in the burden of malaria through a strategy of "scaling-up" effective interventions. Progress toward ultimate malaria elimination will require sustained prevention coverage and further interruption of transmission through active strategies to identify and treat asymptomatic malaria reservoirs. A surveillance system in Zambia's Southern Province has begun to implement such an approach. An early detection system could be an additional tool to identify foci of elevated incidence for targeted intervention. METHODS Based on surveillance data collected weekly from 13 rural health centres (RHCs) divided into three transmission zones, early warning thresholds were created following a technique successfully implemented in Thailand. Alert levels were graphed for all 52 weeks of a year using the mean and 95% confidence interval upper limit of a Poisson distribution of the weekly diagnosed malaria cases for every available week of historic data (beginning in Aug, 2008) at each of the sites within a zone. Annually adjusted population estimates for the RHC catchment areas served as person-time of weekly exposure. The zonal threshold levels were validated against the incidence data from each of the 13 respective RHCs. RESULTS Graphed threshold levels for the three zones generally conformed to observed seasonal incidence patterns. Comparing thresholds with historic weekly incidence values, the overall percentage of aberrant weeks ranged from 1.7% in Mbabala to 36.1% in Kamwanu. For most RHCs, the percentage of weeks above threshold was greater during the high transmission season and during the 2009 year compared to 2010. 39% of weeks breaching alert levels were part of a series of three or more consecutive aberrant weeks. CONCLUSIONS The inconsistent sensitivity of the zonal threshold levels impugns the reliability of the alert system. With more years of surveillance data available, individual thresholds for each RHC could be calculated and compared to the technique outlined here. Until then, "aberrant" weeks during low transmission seasons, and during high transmission seasons at sites where the threshold level is less sensitive, could feasibly be followed up for household screening. Communities with disproportionate numbers of aberrant weeks could be reviewed for defaults in the scaling-up intervention coverage.
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Affiliation(s)
- Ryan G Davis
- Johns Hopkins Bloomberg School of Public Health, Baltimore MD, USA
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Abstract
Malaria in the 21st century is showing signs of declining over much of its distribution, including several countries in Africa where previously this was not thought to be feasible. Yet for the most part the strategies to attack the infection are similar to those of the 1950s. Three major Journals have recently drawn attention to the situation, stressing the importance of research, describing the successes and defining semantics related to control. But there is a need to stress the importance of local sustainability, and consider somewhat urgently how individual endemic countries can plan and implement the programmes that are currently financed, for the most part, by donor institutions. On an immediate basis research should be more focused on a data driven approach to control. This will entail new thinking on the role of local infrastructure and in training of local scientists in local universities in epidemiology and field malariology so that expanded control programmes can become operational. Donor agencies should encourage and facilitate development of career opportunities for such personnel so that local expertise is available to contribute appropriately.
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Affiliation(s)
- Clive Shiff
- Department of Molecular Microbiology and Immunology and Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.
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Moss WJ, Hamapumbu H, Kobayashi T, Shields T, Kamanga A, Clennon J, Mharakurwa S, Thuma PE, Glass G. Use of remote sensing to identify spatial risk factors for malaria in a region of declining transmission: a cross-sectional and longitudinal community survey. Malar J 2011; 10:163. [PMID: 21663661 PMCID: PMC3123248 DOI: 10.1186/1475-2875-10-163] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Accepted: 06/10/2011] [Indexed: 11/26/2022] Open
Abstract
Background The burden of malaria has decreased dramatically within the past several years in parts of sub-Saharan Africa. Further malaria control will require targeted control strategies based on evidence of risk. The objective of this study was to identify environmental risk factors for malaria transmission using remote sensing technologies to guide malaria control interventions in a region of declining burden of malaria. Methods Satellite images were used to construct a sampling frame for the random selection of households enrolled in prospective longitudinal and cross-sectional surveys of malaria parasitaemia in Southern Province, Zambia. A digital elevation model (DEM) was derived from the Shuttle Radar Topography Mission version 3 DEM and used for landscape characterization, including landforms, elevation, aspect, slope, topographic wetness, topographic position index and hydrological models of stream networks. Results A total of 768 individuals from 128 randomly selected households were enrolled over 21 months, from the end of the rainy season in April 2007 through December 2008. Of the 768 individuals tested, 117 (15.2%) were positive by malaria rapid diagnostic test (RDT). Individuals residing within 3.75 km of a third order stream were at increased risk of malaria. Households at elevations above the baseline elevation for the region were at decreasing risk of having RDT-positive residents. Households where new infections occurred were overlaid on a risk map of RDT positive households and incident infections were more likely to be located in high-risk areas derived from prevalence data. Based on the spatial risk map, targeting households in the top 80th percentile of malaria risk would require malaria control interventions directed to only 24% of the households. Conclusions Remote sensing technologies can be used to target malaria control interventions in a region of declining malaria transmission in southern Zambia, enabling a more efficient use of resources for malaria elimination.
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Affiliation(s)
- William J Moss
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA.
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Chidi AP, Chishimba S, Kobayashi T, Hamapumbu H, Mharakurwa S, Thuma PE, Moss WJ. Validation of oral fluid samples to monitor serological changes to Plasmodium falciparum: an observational study in southern Zambia. Malar J 2011; 10:162. [PMID: 21663660 PMCID: PMC3141589 DOI: 10.1186/1475-2875-10-162] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Accepted: 06/10/2011] [Indexed: 11/21/2022] Open
Abstract
Background In formerly endemic areas where malaria transmission has declined, levels of population immunity to Plasmodium falciparum provide information on continued malaria transmission and potentially susceptible populations. Traditional techniques for measuring serological responses to P. falciparum antigens use plasma or dried blood spots (DBS). These invasive procedures pose a biohazard and may be unacceptable to communities if performed frequently. The use of oral fluid (OF) samples to detect antibodies to P. falciparum antigens may be a more acceptable strategy to monitor changes in population immunity. Methods An enzyme immunoassay was optimized to detect antibodies to whole, asexual stage P. falciparum antigens. Optical density (OD) values from paired DBS and OF samples collected as part of a community-based survey of malaria parasitaemia were compared. Results Oral fluid and dried blood spot samples were collected from 53 participants in Southern Province, Zambia. Their ages ranged from 1 to 80 years and 45% were female. A statistically significant correlation (r = 0.79; P < 0.01) was observed between OD values from OF and DBS samples. The OF assay identified all DBS-confirmed positive and negative samples, resulting in 100% sensitivity and specificity. Conclusions Oral fluid is a valid alternative specimen for monitoring changes in antibodies to P. falciparum antigens. As OF collection is often more acceptable to communities, poses less of a biohazard than blood samples and can be performed by community volunteers, serological surveys using OF samples provide a strategy for monitoring population immunity in regions of declining malaria transmission.
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Affiliation(s)
- Alexis P Chidi
- Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
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Pooe OJ, Shonhai A, Mharakurwa S. Optimization of a polymerase chain reaction based assay for the detection of malaria in human saliva samples. Malar J 2010. [PMCID: PMC2963279 DOI: 10.1186/1475-2875-9-s2-p38] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Stresman GH, Kamanga A, Moono P, Hamapumbu H, Mharakurwa S, Kobayashi T, Moss WJ, Shiff C. A method of active case detection to target reservoirs of asymptomatic malaria and gametocyte carriers in a rural area in Southern Province, Zambia. Malar J 2010; 9:265. [PMID: 20920328 PMCID: PMC2959066 DOI: 10.1186/1475-2875-9-265] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Accepted: 10/04/2010] [Indexed: 12/02/2022] Open
Abstract
Background Asymptomatic reservoirs of malaria parasites are common yet are difficult to detect, posing a problem for malaria control. If control programmes focus on mosquito control and treatment of symptomatic individuals only, malaria can quickly resurge if interventions are scaled back. Foci of parasite populations must be identified and treated. Therefore, an active case detection system that facilitates detection of asymptomatic parasitaemia and gametocyte carriers was developed and tested in the Macha region in southern Zambia. Methods Each week, nurses at participating rural health centres (RHC) communicated the number of rapid diagnostic test (RDT) positive malaria cases to a central research team. During the dry season when malaria transmission was lowest, the research team followed up each positive case reported by the RHC by a visit to the homestead. The coordinates of the location were obtained by GPS and all consenting residents completed a questionnaire and were screened for malaria using thick blood film, RDT, nested-PCR, and RT-PCR for asexual and sexual stage parasites. Persons who tested positive by RDT were treated with artemether/lumefantrine (Coartem®). Data were compared with a community-based study of randomly selected households to assess the prevalence of asymptomatic parasitaemia in the same localities in September 2009. Results In total, 186 and 141 participants residing in 23 case and 24 control homesteads, respectively, were screened. In the case homesteads for which a control population was available (10 of the 23), household members of clinically diagnosed cases had a 8.0% prevalence of malaria using PCR compared to 0.7% PCR positive individuals in the control group (p = 0.006). The case and control groups had a gametocyte prevalence of 2.3% and 0%, respectively but the difference was not significant (p = 0.145). Conclusions This pilot project showed that active case detection is feasible and can identify reservoirs of asymptomatic infection. A larger sample size, data over multiple low transmission seasons, and in areas with different transmission dynamics are needed to further validate this approach.
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Affiliation(s)
- Gillian H Stresman
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
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Kamanga A, Moono P, Stresman G, Mharakurwa S, Shiff C. Rural health centres, communities and malaria case detection in Zambia using mobile telephones: a means to detect potential reservoirs of infection in unstable transmission conditions. Malar J 2010; 9:96. [PMID: 20398318 PMCID: PMC2861692 DOI: 10.1186/1475-2875-9-96] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Accepted: 04/15/2010] [Indexed: 11/16/2022] Open
Abstract
Background Effective malaria control depends on timely acquisition of information on new cases, their location and their frequency so as to deploy supplies, plan interventions or focus attention on specific locations appropriately to intervene and prevent an upsurge in transmission. The process is known as active case detection, but because the information is time sensitive, it is difficult to carry out. In Zambia, the rural health services are operating effectively and for the most part are provided with adequate supplies of rapid diagnostic tests (RDT) as well as effective drugs for the diagnosis and treatment of malaria. The tests are administered to all prior to treatment and appropriate records are kept. Data are obtained in a timely manner and distribution of this information is important for the effective management of malaria control operations. The work reported here involves combining the process of positive diagnoses in rural health centres (passive case detection) to help detect potential outbreaks of malaria and target interventions to foci where parasite reservoirs are likely to occur. Methods Twelve rural health centres in the Choma and Namwala Districts were recruited to send weekly information of rapid malaria tests used and number of positive diagnoses to the Malaria Institute at Macha using mobile telephone SMS. Data were entered in excel, expressed as number of cases per rural health centre and distributed weekly to interested parties. Results These data from each of the health centres which were mapped using geographical positioning system (GPS) coordinates were used in a time sensitive manner to plot the patterns of malaria case detection in the vicinity of each location. The data were passed on to the appropriate authorities. The seasonal pattern of malaria transmission associated with local ecological conditions can be seen in the distribution of cases diagnosed. Conclusions Adequate supplies of RDT are essential in health centres and the system can be expanded throughout the country to support strategic targeting of interventions by the National Malaria Control Programme. Participation by the health centre staff was excellent.
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Bulterys PL, Mharakurwa S, Thuma PE. Cattle, other domestic animal ownership, and distance between dwelling structures are associated with reduced risk of recurrent Plasmodium falciparum infection in southern Zambia. Trop Med Int Health 2009; 14:522-8. [PMID: 19389038 DOI: 10.1111/j.1365-3156.2009.02270.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To examine the associations between household Plasmodium falciparum infection and a number of factors including domestic animal ownership, potential mosquito breeding sites, indoor darkness, density of people, distance between dwelling structures, and insecticide-treated bed net use. METHODS Analyses were based on data collected from a household survey conducted in Macha, Zambia. Thirty-four households with recurrent malaria infection in 2005-2008 were selected as case households and compared with 37 control households with no malaria infection randomly selected from the same geographic area. Logistic regression models were used to identify factors associated with household P. falciparum infection. RESULTS In multivariate analysis, cattle ownership was associated with reduced risk of P. falciparum infection (adjusted odds ratio = 0.19; 95% CI = 0.05-0.69), as was increased distance between dwelling structures (aOR = 0.26; 95% CI = 0.07-0.98). Ownership of the highest category of cattle, goats, dogs, or cats dramatically reduced the risk of P. falciparum infection (aOR = 0.13; 95% CI = 0.03-0.56). CONCLUSION Domestic animal, in particular cattle, ownership and greater distance between dwelling structures were associated with reduced risk of recurrent P. falciparum infection at the household level. These factors should be further investigated as supplemental measures for malaria control in rural African settings.
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Affiliation(s)
- Philip L Bulterys
- Department of Biology, Stanford University, Stanford, CA 94309, USA.
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Rouse P, Mkulama MA, Thuma PE, Mharakurwa S. Distinction of Plasmodium falciparum recrudescence and re-infection by MSP2 genotyping: a caution about unstandardized classification criteria. Malar J 2008; 7:185. [PMID: 18811949 PMCID: PMC2556700 DOI: 10.1186/1475-2875-7-185] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2008] [Accepted: 09/23/2008] [Indexed: 11/10/2022] Open
Abstract
Background Plasmodium falciparum genotyping with molecular polymorphic markers is widely employed to distinguish recrudescence from re-infection in antimalarial drug efficacy monitoring programmes. However, limitations occur on agarose gel DNA measurements used to resolve the polymorphisms. Without empirical data, the current distinction of pre- and post-treatment bands, as persistent or new infection, is subjective and often varying by author. This study measures empirical tolerance limits for classifying different-sized bands as same or different alleles during MSP2 genotyping. Methods P. falciparum field samples from 161 volunteers were genotyped by nested PCR using polymorphic MSP2 family-specific primers. Data were analysed to determine variability of band size measurements between identical MSP2 alleles randomized into different agarose lanes. Results The mean (95% CI) paired difference in band size between identical alleles was 9.8 bp (1.48 – 18.16 bp, p = 0.022) for 3D7/IC and 2.54 (-3.04 – 8.05 bp, p = 0.362) for FC27. Based on these findings, pre- and post-treatment samples with 3D7/IC alleles showing less than 18 bp difference corresponded to recrudescence, with 95% confidence, while greater difference indicated new infection. FC27 allele differences were much narrower. For both 3D7/IC and FC27 amplicon, allele detection sensitivity was significantly higher with 13 μl compared to 20 μl or 30 μl lane loading volumes. Conclusion During MSP genotyping, it is useful to standardize classifications against measurement of background variability on identical alleles, in order to obtain reliable findings. It is critical to use a fixed optimal lane loading volume for constant allele patency, to avoid the disappearance or false appearance of new infection.
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Affiliation(s)
- Petrica Rouse
- Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
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