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Moukénet A, Moudiné K, Ngarasta N, Hinzoumbe CK, Seck I. Malaria infection and predictor factors among Chadian nomads' children. BMC Public Health 2024; 24:918. [PMID: 38549091 PMCID: PMC10979592 DOI: 10.1186/s12889-024-18454-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Accepted: 03/26/2024] [Indexed: 04/01/2024] Open
Abstract
BACKGROUND In Chad, malaria remains a significant public health concern, particularly among nomadic populations. Geographical factors and the mobility of human populations have shown to be associated with the diversity of Plasmodium species. The study aims to describe the malaria prevalence among nomadic children and to investigate its associated factors. METHODS A cross-sectional study was conducted in February and October 2021 among nomadic communities in Chad. Blood sample were collected and tested from 187 Arab, Fulani and Dazagada nomadic children aged 3-59 months using malaria rapid diagnostic test (RDT). A structured electronic questionnaire was administered to their parents to collect information about the socio‑economic data. Malaria testing results were categorized according to the SD BIOLINE Malaria Ag Pf/Pan RDT procedures. Logistic regression analysis was used to determine key risk factors explaining the prevalence of malaria. STATA version IC 13 was used for statistical analysis. RESULTS The overall malaria prevalence in nomadic children was 24.60%, with 65.20% being Plasmodium falciparum species and 34.8% mixed species. Boys were twice as likely (COR = 1.83; 95% CI, 0.92-3.62; p = 0.083) to have malaria than girls. Children whose parents used to seek traditional drugs were five times more likely (AOR = 5.59; 95% CI, 1.40-22.30, p = 0.015) to have malaria than children whose parents used to seek health facilities. Children whose parents reported spending the last night under a mosquito net were one-fifth as likely (AOR = 0.17; 95% CI, 0.03-0.90, p = 0.037) to have malaria compared to children whose parents did not used a mosquito net. Furthermore, Daza children were seventeen times (1/0.06) less likely (AOR = 0.06; 95% CI, 0.01-0.70, p = 0.024) to have malaria than Fulani children and children from households piped water as the main source were seven times more likely (AOR = 7.05; 95% CI, 1.69-29.45; p = 0.007) to have malaria than those using surface water. CONCLUSIONS Malaria remains a significant public health issue in the nomadic communities of Chad. Community education and sensitization programs within nomad communities are recommended to raise awareness about malaria transmission and control methods, particularly among those living in remote rural areas. The National Malaria Control Program (NMCP) should increase both the coverage and use of long-lasting insecticidal nets (LLINs) and seasonal malaria chemoprevention (SMC) in addition to promoting treatment-seeking behaviors in nomadic communities.
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Affiliation(s)
- Azoukalné Moukénet
- Cheikh Anta Diop University, Dakar, Senegal.
- University of Ndjamena, Ndjamena, Chad.
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Tangena JAA, Mategula D, Sedda L, Atkinson PM. Unravelling the impact of insecticide-treated bed nets on childhood malaria in Malawi. Malar J 2023; 22:16. [PMID: 36635658 PMCID: PMC9837906 DOI: 10.1186/s12936-023-04448-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 01/06/2023] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND To achieve malaria elimination it is essential to understand the impact of insecticide-treated net (ITNs) programmes. Here, the impact of ITN access and use on malaria prevalence in children in Malawi was investigated using Malaria Indicator Survey (MIS) data. METHODS MIS data from 2012, 2014 and 2017 were used to investigate the relationship between malaria prevalence in children (6-59 months) and ITN use. Generalized linear modelling (GLM), geostatistical mixed regression modelling and non-stationary GLM were undertaken to evaluate trends, spatial patterns and local dynamics, respectively. RESULTS Malaria prevalence in Malawi was 27.1% (95% CI 23.1-31.2%) in 2012 and similar in both 2014 (32.1%, 95% CI 25.5-38.7) and 2017 (23.9%, 95% CI 20.3-27.4%). ITN coverage and use increased during the same time period, with household ITN access growing from 19.0% (95% CI 15.6-22.3%) of households with at least 1 ITN for every 2 people sleeping in the house the night before to 41.7% (95% CI 39.1-44.4%) and ITN use from 41.1% (95% CI 37.3-44.9%) of the population sleeping under an ITN the previous night to 57.4% (95% CI 55.0-59.9%). Both the geostatistical and non-stationary GLM regression models showed child malaria prevalence had a negative association with ITN population access and a positive association with ITN use although affected by large uncertainties. The non-stationary GLM highlighted the spatital heterogeneity in the relationship between childhood malaria and ITN dynamics across the country. CONCLUSION Malaria prevalence in children under five had a negative association with ITN population access and a positive association with ITN use, with spatial heterogeneity in these relationships across Malawi. This study presents an important modelling approach that allows malaria control programmes to spatially disentangle the impact of interventions on malaria cases.
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Affiliation(s)
- Julie-Anne A. Tangena
- grid.48004.380000 0004 1936 9764Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Donnie Mategula
- grid.48004.380000 0004 1936 9764Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, UK ,grid.419393.50000 0004 8340 2442Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Luigi Sedda
- grid.9835.70000 0000 8190 6402Lancaster Ecology and Epidemiology Group, Lancaster University, Lancaster, UK
| | - Peter M. Atkinson
- grid.9835.70000 0000 8190 6402Lancaster Environment Centre, Lancaster University, Bailrigg, Lancaster, LA1 4YR UK ,grid.5491.90000 0004 1936 9297Geography and Environmental Science, University of Southampton, Highfield, Southampton, SO17 1BJ UK ,grid.9227.e0000000119573309Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 11A Datun Road, Beijing, 100101 China
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Cohee LM, Goupeyou-Youmsi J, Seydel KB, Mangani C, Ntenda P, Sixpence A, Mbewe RB, Matengeni A, Takala-Harrison S, Walker ED, Wilson ML, Mzilahowa T, Laufer MK, Valim C, Taylor TE, Mathanga DP. Understanding the Intransigence of Malaria in Malawi. Am J Trop Med Hyg 2022; 107:40-48. [PMID: 36228915 PMCID: PMC9662216 DOI: 10.4269/ajtmh.21-1263] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 03/19/2022] [Indexed: 01/29/2023] Open
Abstract
Despite the scale-up of interventions against malaria over the past decade, this disease remains a leading threat to health in Malawi. To evaluate the epidemiology of both Plasmodium falciparum infection and malaria disease, the Malawi International Center of Excellence for Malaria Research (ICEMR) has developed and implemented diverse and robust surveillance and research projects. Descriptive studies in ICEMR Phase 1 increased our understanding of the declining effectiveness of long-lasting insecticidal nets (LLINs), the role of school-age children in malaria parasite transmission, and the complexity of host-parasite interactions leading to disease. These findings informed the design of ICEMR Phase 2 to test hypotheses about LLIN use and effectiveness, vector resistance to insecticides, demographic targets of malaria control, patterns and causes of asymptomatic to life-threatening disease, and the impacts of RTS,S vaccination plus piperonyl butoxide-treated LLINs on infection and disease in young children. These investigations are helping us to understand mosquito-to-human and human-to-mosquito transmission in the context of Malawi's intransigent malaria problem.
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Affiliation(s)
- Lauren M. Cohee
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | | | - Karl B. Seydel
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan
| | - Charles Mangani
- School of Public Health, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Peter Ntenda
- Malaria Alert Centre, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Alick Sixpence
- Malaria Alert Centre, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Rex B. Mbewe
- Department of Physics and Biochemical Sciences, Malawi University of Business and Applied Sciences, Blantyre, Malawi
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan
| | - Alfred Matengeni
- Malaria Alert Centre, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Shannon Takala-Harrison
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Edward D. Walker
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan
| | - Mark L. Wilson
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, Michigan
| | - Themba Mzilahowa
- Malaria Alert Centre, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Miriam K. Laufer
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Clarissa Valim
- Department of Global Health, Boston University School of Public Health, Boston, Massachusetts
| | - Terrie E. Taylor
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan
| | - Don P. Mathanga
- Malaria Alert Centre, Kamuzu University of Health Sciences, Blantyre, Malawi
- School of Public Health, Kamuzu University of Health Sciences, Blantyre, Malawi
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Mangani C, Mzilahowa T, Cohee L, Kayange M, Ntenda P, Sixpence A, Gumbo A, Lankhulani S, Goupeyou-Youmsi J, Walker E, Laufer M, Valim C, Seydel K, Wilson ML, Taylor T, Mathanga DP. Malawi ICEMR Malaria Research: Interactions and Results Influencing Health Policies and Practices. Am J Trop Med Hyg 2022; 107:49-54. [PMID: 36228911 PMCID: PMC9662217 DOI: 10.4269/ajtmh.21-1265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 05/14/2022] [Indexed: 01/29/2023] Open
Abstract
Malaria remains a threat to public health in Malawi. It is well acknowledged that malaria research and robust evidence can have an impact on malaria policy and practice, resulting in positive population health gains. We report policy-relevant research contributions that the Malawi International Center of Excellence for Malaria Research (ICEMR) in partnership with local and international collaborators has made. Findings from our ICEMR studies have shown that long-lasting insecticide-treated bed nets (LLINs) impregnated with piperonyl butoxide reduced mosquito blood feeding more compared with conventional LLINs. On the other hand, we showed that few LLINs are maintained up to the end of their 3-year life span, and that older nets are less effective. These results support the policy change decisions by the Malawi National Malaria Control Program to switch from conventional LLINs to piperonyl butoxide LLINs, and to conduct mass LLIN distribution campaigns every 2 years. Our studies on epidemiological patterns of malaria infection showed that school-age children have higher malaria infection rates and lower use of control measures compared with younger children and adults. These findings added to the evidence base that influenced the National Malaria Control Program to endorse school-based malaria interventions as part of its national policy. Research supported by the Malawi ICEMR is contributing to in-country policy decisions and to the implementation of evidence-based interventions. Through our long-term studies we intend to continue providing practical and policy-relevant evidence necessary, ultimately, to eliminate malaria infection in Malawi.
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Affiliation(s)
- Charles Mangani
- Department of Epidemiology and Biostatistics, School of Public Health, Kamuzu University of Health Sciences, Blantyre, Malawi;,Address correspondence to Charles Mangani, Department of Epidemiology and Biostatistics, Kamuzu University of Health Sciences, P/Bag 360 Chichiri, Blantyre 3. E-mail:
| | - Themba Mzilahowa
- Malaria Alert Center, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Lauren Cohee
- Department of Pediatrics, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Michael Kayange
- National Malaria Control Program, Ministry of Health, Lilongwe, Malawi
| | - Peter Ntenda
- Malaria Alert Center, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Alick Sixpence
- Malaria Alert Center, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Austin Gumbo
- National Malaria Control Program, Ministry of Health, Lilongwe, Malawi
| | - Sosten Lankhulani
- National Malaria Control Program, Ministry of Health, Lilongwe, Malawi
| | | | - Edward Walker
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan
| | - Miriam Laufer
- Department of Pediatrics, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland
| | - Clarissa Valim
- Department of Global Health, Boston University School of Public Health, Boston, Massachusetts
| | - Karl Seydel
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan
| | - Mark L. Wilson
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, Michigan
| | - Terrie Taylor
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan
| | - Don P. Mathanga
- Department of Epidemiology and Biostatistics, School of Public Health, Kamuzu University of Health Sciences, Blantyre, Malawi;,Malaria Alert Center, Kamuzu University of Health Sciences, Blantyre, Malawi
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Chiuya T, Villinger J, Falzon LC, Alumasa L, Amanya F, Bastos ADS, Fèvre EM, Masiga DK. Molecular screening reveals non-uniform malaria transmission in western Kenya and absence of Rickettsia africae and selected arboviruses in hospital patients. Malar J 2022; 21:268. [PMID: 36115978 PMCID: PMC9482282 DOI: 10.1186/s12936-022-04287-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 09/07/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
In sub-Saharan Africa, malaria is the common diagnosis for febrile illness and related clinical features, resulting in the under-diagnosis of other aetiologies, such as arboviruses and Rickettsia. While these may not be significant causes of mortality in malaria-endemic areas, they affect the daily life and performance of affected individuals. It is, therefore, important to have a clear picture of these other aetiologies to institute correct diagnoses at hospitals and improve patient outcomes.
Methods
Blood samples were collected from patients with fever and other clinical features associated with febrile illness at selected hospitals in the malaria-endemic counties of Busia, Bungoma, and Kakamega, and screened for Crimean-Congo haemorrhagic fever, Sindbis, dengue and chikungunya viruses, Rickettsia africae, and Plasmodium spp. using high-throughput real-time PCR techniques. A logistic regression was performed on the results to explore the effect of demographic and socio-economic independent variables on malaria infection.
Results
A total of 336 blood samples collected from hospital patients between January 2018 and February 2019 were screened, of which 17.6% (59/336) were positive for Plasmodium falciparum and 1.5% (5/336) for Plasmodium malariae. Two patients had dual P. falciparum/P. malariae infections. The most common clinical features reported by the patients who tested positive for malaria were fever and headache. None of the patients were positive for the arboviruses of interest or R. africae. Patients living in Busia (OR 5.2; 95% CI 2.46–11.79; p < 0.001) and Bungoma counties (OR 2.7; 95% CI 1.27–6.16; p = 0.013) had higher odds of being infected with malaria, compared to those living in Kakamega County.
Conclusions
The reported malaria prevalence is in line with previous studies. The absence of arboviral and R. africae cases in this study may have been due to the limited number of samples screened, low-level circulation of arboviruses during inter-epidemic periods, and/or the use of PCR alone as a detection method. Other sero-surveys confirming their circulation in the area indicate that further investigations are warranted.
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Kumala J, Koekemoer LL, Coetzee M, Mzilahowa T. Intensity of insecticide resistance in the major malaria vector Anopheles funestus from Chikwawa, rural Southern Malawi. Parasit Vectors 2022; 15:220. [PMID: 35729623 PMCID: PMC9210055 DOI: 10.1186/s13071-022-05299-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 04/26/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria vector control using insecticide-based approaches has proven to be an effective strategy. However, widespread insecticide resistance among malaria vector populations across sub-Saharan Africa threatens to derail control efforts. This study was conducted in Chikwawa district, an area in rural southern Malawi characterised by persistent malaria transmission and reports of insecticide resistance in the local mosquito population. The aim of the was to characterise the intensity of insecticide resistance within a population of Anopheles funestus sensu lato (s.l.), a major vector of malaria in this district. METHODS Live adult females belonging to the An. funestus group were collected from households by indoor aspiration. The CDC bottle assay was used for phenotypic quantification of resistance to deltamethrin, permethrin and alpha-cypermethrin at 1×, 2.5×, 5× and 10× the recommended diagnostic dose for each of these insecticides. WHO tube assays were used to determine susceptibility to bendiocarb, dichlorodiphenyltrichloroethane (DDT) and pirimiphos-methyl insecticides at diagnostic concentrations. RESULTS Anopheles funestus s.l. exposed to 10× the recommended diagnostic dose was highly resistant to alpha-cypermethrin (mortality 95.4%); in contrast, mortality was 100% when exposed to both deltamethrin and permethrin at the same dose. Despite showing susceptibility to deltamethrin and permethrin at the 10× concentration, mortality at the 5× concentration was 96.7% and 97.1%, respectively, indicating moderate resistance to these two insecticides. WHO susceptibility assays indicated strong resistance against bendiocarb (mortality 33.8%, n = 93), whereas there was full susceptibility to DDT (mortality 98.9%, n = 103) and pirimiphos-methyl (mortality 100%, n = 103). CONCLUSIONS Strategies for managing resistance to insecticides, particularly against pyrethroids, must be urgently implemented to maintain the effectiveness of insecticide-based vector control interventions in the area. Such strategies include the wide-scale introduction of third-generation synergist insecticide-treated bed nets (ITNs) and next-generation dual active ingredient ITNs. The use of effective non-pyrethroids, such as pirimiphos-methyl, clothianidin and potentially DDT, could provide a window of opportunity for indoor residual spraying across the district. This strategy would support the current Malawi Insecticide Resistance Management Plan which aims at rotating insecticides to minimise selection pressure and slow down the evolution of resistance to approved insecticides. These actions will help to prevent malaria vector control failure and improve progress towards malaria elimination.
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Affiliation(s)
- Justin Kumala
- Malaria Alert Centre-Communicable Diseases Action Centre (MAC-CDAC), Kamuzu University of Health Sciences, Blantyre, Malawi.,Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Centre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Lizette L Koekemoer
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Centre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Maureen Coetzee
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,Centre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Themba Mzilahowa
- Malaria Alert Centre-Communicable Diseases Action Centre (MAC-CDAC), Kamuzu University of Health Sciences, Blantyre, Malawi.
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Kamau A, Musau M, Mtanje G, Mataza C, Bejon P, Snow RW. OUP accepted manuscript. Trans R Soc Trop Med Hyg 2022; 116:966-970. [PMID: 35415749 PMCID: PMC9526839 DOI: 10.1093/trstmh/trac029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 01/25/2022] [Accepted: 03/18/2022] [Indexed: 11/14/2022] Open
Affiliation(s)
- Alice Kamau
- Corresponding author: Tel: +254-722 203417; E-mail:
| | - Moses Musau
- KEMRI-Wellcome Trust Research Programme, P.O. Box 43640-00100, Nairobi, Kenya
| | - Grace Mtanje
- KEMRI-Wellcome Trust Research Programme, P.O. Box 43640-00100, Nairobi, Kenya
| | - Christine Mataza
- KEMRI-Wellcome Trust Research Programme, P.O. Box 43640-00100, Nairobi, Kenya
- Ministry of Health, Kilifi County Government, P.O. Box 519-80108, Kilifi, Kenya
| | - Philip Bejon
- KEMRI-Wellcome Trust Research Programme, P.O. Box 43640-00100, Nairobi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, New Richards Building, Old Road Campus, Roosevelt Drive, OX3 7LG, Oxford, UK
| | - Robert W Snow
- KEMRI-Wellcome Trust Research Programme, P.O. Box 43640-00100, Nairobi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, New Richards Building, Old Road Campus, Roosevelt Drive, OX3 7LG, Oxford, UK
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Rodriguez MH. Residual Malaria: Limitations of Current Vector Control Strategies to Eliminate Transmission in Residual Foci. J Infect Dis 2021; 223:S55-S60. [PMID: 33906220 PMCID: PMC8079132 DOI: 10.1093/infdis/jiaa582] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The transmission of Plasmodium parasites in residual foci is currently a major roadblock for malaria elimination. Human activities and behavior, along with outdoor biting mosquitoes with opportunistic feeding preferences are the main causes of the inefficacy of the main vector control interventions, long lasting insecticide-impregnated nets and insecticide residual spraying. Several strategies to abate or repel outdoor biting mosquito vectors are currently being researched, but the impact of insecticide resistance on the efficacy of these and current indoor-applied insecticides requires further assessment. Understanding the human, ecological and vector factors, determining transmission in residual foci is necessary for the design and implementation of novel control strategies. Vector control alone is insufficient without adequate epidemiological surveillance and prompt treatment of malaria cases, the participation of endemic communities in prevention and control is required. In addition, malaria control programs should optimize their structure and organization, and their coordination with other government sectors.
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Affiliation(s)
- Mario H Rodriguez
- Centro de Investigaciones Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, Mexico
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Guglielmo F, Sanou A, Churcher T, Ferguson HM, Ranson H, Sherrard-Smith E. Quantifying individual variability in exposure risk to mosquito bites in the Cascades region, Burkina Faso. Malar J 2021; 20:44. [PMID: 33461560 PMCID: PMC7814650 DOI: 10.1186/s12936-020-03538-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 12/07/2020] [Indexed: 12/21/2022] Open
Abstract
Background The Cascades region, Burkina Faso, has a high malaria burden despite reported high insecticide-treated mosquito net (ITN) use. Human and vector activities outside the hours when indoor interventions offer direct protection from infectious bites potentially increase exposure risk to bites from malaria-transmitting Anopheles mosquitoes. This work investigated the degree of variation in human behaviour both between individuals and through time (season) to quantify how it impacts exposure to malaria vectors. Methods Patterns in human overnight activity (18:00–06:00) to quantify time spent using an ITN across 7 successive nights in two rural communities, Niakore (N = 24 participants) and Toma (71 participants), were observed in the dry and rainy seasons, between 2017 and 2018. Hourly human landing Anopheles mosquito catches were conducted in Niakore specifically, and Cascades region generally, between 2016 and 2017. Data were statistically combined to estimate seasonal variation in time spent outdoors and Anopheles bites received per person per night (bpppn). Results Substantial variability in exposure to outdoor Anopheles bites was detected within and between communities across seasons. In October, when Anopheles densities are highest, an individual’s risk of Anopheles bites ranged from 2.2 to 52.2 bites per person per night (bpppn) within the same week with variable risk dependent on hours spent indoors. Comparably higher outdoor human activity was observed in April and July but, due to lower Anopheles densities estimated, bpppn were 0.2–4.7 and 0.5–32.0, respectively. Males and people aged over 21 years were predicted to receive more bites in both sentinel villages. Conclusion This work presents one of the first clear descriptions of the degree of heterogeneity in time spent outdoors between people and across the year. Appreciation of sociodemographic, cultural and entomological activities will help refine approaches to vector control.
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Affiliation(s)
- Federica Guglielmo
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
| | - Antoine Sanou
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK. .,Centre National de Recherche et de Formation sur le Paludisme, BP 2208, Ouagadougou 01, Burkina Faso.
| | - Thomas Churcher
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, St Mary's Campus, London, W2 1PG, UK
| | - Heather M Ferguson
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Hilary Ranson
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Ellie Sherrard-Smith
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
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10
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Wotodjo AN, Doucoure S, Diagne N, Sarr FD, Parola P, Gaudart J, Sokhna C. The Impact of Renewing Long-Lasting Insecticide-Treated Nets in the Event of Malaria Resurgence: Lessons from 10 Years of Net Use in Dielmo, Senegal. Am J Trop Med Hyg 2020; 104:255-262. [PMID: 33078700 DOI: 10.4269/ajtmh.20-0127] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The occurrence of malaria resurgences could threaten progress toward elimination of the disease. This study investigated the impact of repeated renewal of long-lasting insecticide-treated net (LLIN) universal coverage on malaria resurgence over a period of 10 years of net implementation in Dielmo (Senegal). A longitudinal study was carried out in Dielmo between August 2007 and July 2018. In July 2008, LLINs were offered to all villagers through universal campaign distribution which was renewed in July 2011, August 2014, and May 2016. Malaria cases were treated with artemisinin-based combination therapy. Two resurgences of malaria occurred during the 10 years in which LLINs have been in use. Since the third renewal of the nets, malaria decreased significantly compared with the first year the nets were implemented (adjusted incidence rate ratio) (95% CI) = 0.35 (0.15-0.85), during the ninth year after net implementation). During the tenth year of net implementation, no cases of malaria were observed among the study population. The use of nets increased significantly after the third time the nets were renewed when compared with the year after the first and the second times the nets were renewed (P < 0.001). The third renewal of nets, which took place after 2 years instead of 3 years together with a higher use of LLINs especially among the young, probably prevented the occurrence of a third malaria upsurge in this village.
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Affiliation(s)
| | | | | | - Fatoumata Diene Sarr
- 2Unité d'Épidémiologie des Maladies Infectieuses, Institut Pasteur de Dakar, Dakar, Senegal
| | - Philippe Parola
- 3IRD, AP-HM, SSA, IHU-Méditerranée Infection, VITROME, Aix-Marseille University, Marseille, France
| | - Jean Gaudart
- 4APHM, INSERM, IRD, SESSTIM, Hop Timone, BioSTIC, Biostatistic and ICT, Aix Marseille University, Marseille, France.,5Malaria Research and Training Center - Ogobara K Doumbo (MRTC-OKD), FMOS-FAPH, Mali-NIAID-ICER, Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Cheikh Sokhna
- 1VITROME, UMR 257 IRD, Campus UCAD-IRD, Dakar, Senegal
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