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Korsah MA, Johnston ST, Tiedje KE, Day KP, Flegg JA, Walker CR. Mathematical Assessment of the Role of Intervention Programs for Malaria Control. Bull Math Biol 2024; 86:91. [PMID: 38888640 PMCID: PMC11189351 DOI: 10.1007/s11538-024-01321-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Accepted: 06/03/2024] [Indexed: 06/20/2024]
Abstract
Malaria remains a global health problem despite the many attempts to control and eradicate it. There is an urgent need to understand the current transmission dynamics of malaria and to determine the interventions necessary to control malaria. In this paper, we seek to develop a fit-for-purpose mathematical model to assess the interventions needed to control malaria in an endemic setting. To achieve this, we formulate a malaria transmission model to analyse the spread of malaria in the presence of interventions. A sensitivity analysis of the model is performed to determine the relative impact of the model parameters on disease transmission. We explore how existing variations in the recruitment and management of intervention strategies affect malaria transmission. Results obtained from the study imply that the discontinuation of existing interventions has a significant effect on malaria prevalence. Thus, the maintenance of interventions is imperative for malaria elimination and eradication. In a scenario study aimed at assessing the impact of long-lasting insecticidal nets (LLINs), indoor residual spraying (IRS), and localized individual measures, our findings indicate that increased LLINs utilization and extended IRS coverage (with longer-lasting insecticides) cause a more pronounced reduction in symptomatic malaria prevalence compared to a reduced LLINs utilization and shorter IRS coverage. Additionally, our study demonstrates the impact of localized preventive measures in mitigating the spread of malaria when compared to the absence of interventions.
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Affiliation(s)
- Maame Akua Korsah
- School of Mathematics and Statistics, The University of Melbourne, Melbourne, Australia.
| | - Stuart T Johnston
- School of Mathematics and Statistics, The University of Melbourne, Melbourne, Australia
| | - Kathryn E Tiedje
- Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne, Melbourne, Australia
| | - Karen P Day
- Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne, Melbourne, Australia
| | - Jennifer A Flegg
- School of Mathematics and Statistics, The University of Melbourne, Melbourne, Australia
| | - Camelia R Walker
- School of Mathematics and Statistics, The University of Melbourne, Melbourne, Australia
- Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
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Parker JEA, Kakilla C, Nelwin K, Kroner C, Logan R, Ismail HM, Towers C, Manjurano A, Towers D, McCall PJ. Video-tracked Anopheles arabiensis entry and exit behaviour at washed and damaged pyrethroid-treated bednets. ROYAL SOCIETY OPEN SCIENCE 2024; 11:231165. [PMID: 39076790 PMCID: PMC11285834 DOI: 10.1098/rsos.231165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 04/03/2024] [Accepted: 04/05/2024] [Indexed: 07/31/2024]
Abstract
Insecticide-treated nets (ITNs) are the most effective method for malaria prevention in Africa. Using near-infrared video tracking in a laboratory environment, we recorded and assessed bednet entry and exit by a northern Tanzanian population of Anopheles arabiensis at a human-occupied untreated net and a PermaNet® 2.0 ITN. Both had 12 holes, each 10 cm in diameter, punctured at specific locations, and the ITN was washed 20 times to further simulate the wear and tear of ageing. Washing reduced the insecticide content of ITNs by 61%, which then showed similar rates to the untreated nets for net entry (39% entered untreated net and 41% entered ITN; p = 0.84) and exit (37% and 43%, respectively; p = 0.67). Regardless of treatment, approximately 40% of mosquitoes entered nets within 20 s of first appearing in the field of view and reached the volunteer's skin within 5 s of entering the net. Mortality rates post-exposure were significantly higher (p = 0.048) at ITNs (26.6%; 95% CI 13.4%-39.7%) than at untreated controls (6.4%; 95% CI 1.8%-14.6%). The washed and aged ITN provided little additional personal protection for the sleeper over an untreated net. Simple adjustments to materials and design that could extend the effective lifespan of ITNs are discussed.
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Affiliation(s)
- J. E. A. Parker
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - C. Kakilla
- National Institute of Medical Research, Mwanza, Tanzania
| | - K. Nelwin
- National Institute of Medical Research, Mwanza, Tanzania
| | - C. Kroner
- School of Engineering, University of Warwick, Coventry, UK
| | - R. Logan
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
- Parasitology Department, Heidelberg University Hospital, Heidelberg, Germany
| | - H. M. Ismail
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - C. Towers
- School of Engineering, University of Warwick, Coventry, UK
| | - A. Manjurano
- National Institute of Medical Research, Mwanza, Tanzania
| | - D. Towers
- School of Engineering, University of Warwick, Coventry, UK
| | - P. J. McCall
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
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Sadoine ML, Zinszer K, Liu Y, Gachon P, Fournier M, Dueymes G, Dorsey G, Llerena A, Namuganga JF, Nasri B, Smargiassi A. Predicting malaria risk considering vector control interventions under climate change scenarios. Sci Rep 2024; 14:2430. [PMID: 38286803 PMCID: PMC10824718 DOI: 10.1038/s41598-024-52724-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 01/23/2024] [Indexed: 01/31/2024] Open
Abstract
Many studies have projected malaria risks with climate change scenarios by modelling one or two environmental variables and without the consideration of malaria control interventions. We aimed to predict the risk of malaria with climate change considering the influence of rainfall, humidity, temperatures, vegetation, and vector control interventions (indoor residual spraying (IRS) and long-lasting insecticidal nets (LLIN)). We used negative binomial models based on weekly malaria data from six facility-based surveillance sites in Uganda from 2010-2018, to estimate associations between malaria, environmental variables and interventions, accounting for the non-linearity of environmental variables. Associations were applied to future climate scenarios to predict malaria distribution using an ensemble of Regional Climate Models under two Representative Concentration Pathways (RCP4.5 and RCP8.5). Predictions including interaction effects between environmental variables and interventions were also explored. The results showed upward trends in the annual malaria cases by 25% to 30% by 2050s in the absence of intervention but there was great variability in the predictions (historical vs RCP 4.5 medians [Min-Max]: 16,785 [9,902-74,382] vs 21,289 [11,796-70,606]). The combination of IRS and LLIN, IRS alone, and LLIN alone would contribute to reducing the malaria burden by 76%, 63% and 35% respectively. Similar conclusions were drawn from the predictions of the models with and without interactions between environmental factors and interventions, suggesting that the interactions have no added value for the predictions. The results highlight the need for maintaining vector control interventions for malaria prevention and control in the context of climate change given the potential public health and economic implications of increasing malaria in Uganda.
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Affiliation(s)
- Margaux L Sadoine
- School of Public Health, Université de Montréal, Montreal, Quebec, Canada.
- Center for Public Health Research, Université de Montréal, Montreal, Quebec, Canada.
| | - Kate Zinszer
- School of Public Health, Université de Montréal, Montreal, Quebec, Canada
- Center for Public Health Research, Université de Montréal, Montreal, Quebec, Canada
| | - Ying Liu
- School of Public Health, Université de Montréal, Montreal, Quebec, Canada
- Center for Public Health Research, Université de Montréal, Montreal, Quebec, Canada
| | - Philippe Gachon
- ESCER (Étude et Simulation du Climat à l'Échelle Régionale) Centre, Université du Québec à Montréal, Montreal, Quebec, Canada
| | - Michel Fournier
- Department of Public Health, Montreal Regional, Montreal, Quebec, Canada
| | - Guillaume Dueymes
- ESCER (Étude et Simulation du Climat à l'Échelle Régionale) Centre, Université du Québec à Montréal, Montreal, Quebec, Canada
| | - Grant Dorsey
- University of California San Francisco, San Francisco, USA
| | - Ana Llerena
- Department of Earth and Atmospheric Sciences, Université du Québec à Montréal, Montreal, Quebec, Canada
| | | | - Bouchra Nasri
- School of Public Health, Université de Montréal, Montreal, Quebec, Canada
- Center for Public Health Research, Université de Montréal, Montreal, Quebec, Canada
| | - Audrey Smargiassi
- School of Public Health, Université de Montréal, Montreal, Quebec, Canada
- Center for Public Health Research, Université de Montréal, Montreal, Quebec, Canada
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Sadoine ML, Smargiassi A, Liu Y, Gachon P, Fournier M, Dueymes G, Namuganga JF, Dorsey G, Nasri B, Zinszer K. Differential Influence of Environmental Factors on Malaria Due to Vector Control Interventions in Uganda. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:7042. [PMID: 37998273 PMCID: PMC10671539 DOI: 10.3390/ijerph20227042] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 10/23/2023] [Accepted: 11/06/2023] [Indexed: 11/25/2023]
Abstract
BACKGROUND Few studies have explored how vector control interventions may modify associations between environmental factors and malaria. METHODS We used weekly malaria cases reported from six public health facilities in Uganda. Environmental variables (temperature, rainfall, humidity, and vegetation) were extracted from remote sensing sources. The non-linearity of environmental variables was investigated, and negative binomial regression models were used to explore the influence of indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs) on associations between environmental factors and malaria incident cases for each site as well as pooled across the facilities, with or without considering the interaction between environmental variables and vector control interventions. RESULTS An average of 73.3 weekly malaria cases per site (range: 0-597) occurred between 2010 and 2018. From the pooled model, malaria risk related to environmental variables was reduced by about 35% with LLINs and 63% with IRS. Significant interactions were observed between some environmental variables and vector control interventions. There was site-specific variability in the shape of the environment-malaria risk relationship and in the influence of interventions (6 to 72% reduction in cases with LLINs and 43 to 74% with IRS). CONCLUSION The influence of vector control interventions on the malaria-environment relationship need to be considered at a local scale in order to efficiently guide control programs.
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Affiliation(s)
- Margaux L. Sadoine
- Department of Social and Preventive Medicine, School of Public Health, Université de Montréal, Montreal, QC H3N 1X9, Canada
- Center for Public Health Research, Université de Montréal, Montreal, QC H3N 1X9, Canada
| | - Audrey Smargiassi
- Center for Public Health Research, Université de Montréal, Montreal, QC H3N 1X9, Canada
- Department of Environmental and Occupational Health, School of Public Health, Université de Montréal, Montreal, QC H3T 1A8, Canada
| | - Ying Liu
- Center for Public Health Research, Université de Montréal, Montreal, QC H3N 1X9, Canada
- Department of Environmental and Occupational Health, School of Public Health, Université de Montréal, Montreal, QC H3T 1A8, Canada
| | - Philippe Gachon
- ESCER (Étude et Simulation du Climat à l’Échelle Régionale) Centre, Université du Québec à Montréal, Montreal, QC H2L 2C4, Canada
| | - Michel Fournier
- Montreal Regional Department of Public Health, Montreal, QC H2L 1M3, Canada
| | - Guillaume Dueymes
- ESCER (Étude et Simulation du Climat à l’Échelle Régionale) Centre, Université du Québec à Montréal, Montreal, QC H2L 2C4, Canada
| | | | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, CA 94143, USA
| | - Bouchra Nasri
- Department of Social and Preventive Medicine, School of Public Health, Université de Montréal, Montreal, QC H3N 1X9, Canada
- Center for Public Health Research, Université de Montréal, Montreal, QC H3N 1X9, Canada
| | - Kate Zinszer
- Department of Social and Preventive Medicine, School of Public Health, Université de Montréal, Montreal, QC H3N 1X9, Canada
- Center for Public Health Research, Université de Montréal, Montreal, QC H3N 1X9, Canada
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da Silva Ferreira Lima AC, Galardo AKR, Müller JN, de Andrade Corrêa APS, Ribeiro KAN, Silveira GA, Hijjar AV, Soares da Roch Bauzer LG, Lima JBP. Evaluation of Long-lasting insecticidal nets (LLINs) for malaria control in an endemic area in Brazil. Parasit Vectors 2023; 16:162. [PMID: 37173754 PMCID: PMC10182611 DOI: 10.1186/s13071-023-05759-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 03/29/2023] [Indexed: 05/15/2023] Open
Abstract
BACKGROUND Most cases of malaria in Brazil are concentrated in the Amazon region. One of the vector control alternatives recommended by the WHO is the long-lasting insecticidal net (LLIN). This tool is used in the nine federal states of the Brazilian Legal Amazon, where LLINs are essential for reducing vector density and disease transmission as they prevent contact between the mosquito and the individual. The objective of this study was to evaluate the residuality and use of LLIN insecticides in different health regions in a city located in the Brazilian Amazon. METHODS A total of 17,027 LLINs were installed in the third, fifth and ninth health regions of the municipality of Porto Velho, Rondonia State, Brazil. The LLINs were of two types: Olyset (permethrin), for around the bed, and Interceptor (alphacypermethrin), for around hammocks. The residuality of 172 LLINs was evaluated using cone bioassays to verify the mortality rate of the mosquito Nyssorhynchus darlingi, over a period of 2 years. Structured questionnaires on the acceptance and use of LLINs were distributed to the participating population (n = 391), covering a total sample of 1147 mosquito nets. The mortality rate was evaluated both in terms of days after LLIN installation and the type of insecticide used. Statistical analyses were based on analysis of variance (ANOVA) and Chi-square and were performed using the SPSS statistical program. RESULTS For the Ny. darlingi mosquito, Interceptor-type LLINs showed residual efficacy, with mortality rates ≥ 80% during the 2-year study period, as determined by the WHO. In contrast, Olyset-type LLINs were associated with a reduction in mortality rates, with 76% and 45% mortality rates in the last two assessments, which occurred during the last 6 months of the study period. Based on the structured questionnaires, the acceptance rate, i.e. percentage of individuals accepting the permanence of the 1147 LLINs sampled, in the three health regions of Porto Velho was 93.8% (of 1076 LLINs). CONCLUSION The alphacypermethrin-impregnated LLIN was more effective than the LLIN impregnated with permethrin. The results indicate that the correct use of mosquito nets-and consequently the protection of the population-needs to be supported by health promotion actions. These initiatives are considered to be essential for the success of this vector control strategy. New studies that consider the monitoring of the placement of mosquito nets are necessary to provide effective support in the correct use of this methodology.
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Affiliation(s)
- Ana Cristina da Silva Ferreira Lima
- Laboratório de Entomologia Médica, Instituto de Pesquisas Científicas e Tecnológicas do Estado do Amapá (IEPA), Macapá, Amapá, Brazil
- Laboratório de Fisiologia e Controle de Artrópodes Vetores, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
- Programa de Pós-Graduação em Medicina Tropical, Instituto Oswaldo Cruz FIOCRUZ, Rio de Janeiro, Brazil
| | - Allan Kardec Ribeiro Galardo
- Laboratório de Entomologia Médica, Instituto de Pesquisas Científicas e Tecnológicas do Estado do Amapá (IEPA), Macapá, Amapá, Brazil
| | - Josiane Nogueira Müller
- Laboratório de Entomologia Médica, Instituto de Pesquisas Científicas e Tecnológicas do Estado do Amapá (IEPA), Macapá, Amapá, Brazil.
- Laboratório de Fisiologia e Controle de Artrópodes Vetores, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.
- Programa de Pós-Graduação em Medicina Tropical, Instituto Oswaldo Cruz FIOCRUZ, Rio de Janeiro, Brazil.
| | - Ana Paula Sales de Andrade Corrêa
- Laboratório de Entomologia Médica, Instituto de Pesquisas Científicas e Tecnológicas do Estado do Amapá (IEPA), Macapá, Amapá, Brazil
- Laboratório de Fisiologia e Controle de Artrópodes Vetores, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
- Programa de Pós-Graduação em Medicina Tropical, Instituto Oswaldo Cruz FIOCRUZ, Rio de Janeiro, Brazil
| | | | | | | | | | - José Bento Pereira Lima
- Laboratório de Fisiologia e Controle de Artrópodes Vetores, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
- Programa de Pós-Graduação em Medicina Tropical, Instituto Oswaldo Cruz FIOCRUZ, Rio de Janeiro, Brazil
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Hiruy HN, Irish SR, Abdelmenan S, Wuletaw Y, Zewde A, Woyessa A, Haile M, Chibsa S, Lorenz L, Worku A, Yukich J, Berhane Y, Keating J. Durability of long-lasting insecticidal nets (LLINs) in Ethiopia. Malar J 2023; 22:109. [PMID: 36967389 PMCID: PMC10041722 DOI: 10.1186/s12936-023-04540-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 03/22/2023] [Indexed: 03/28/2023] Open
Abstract
BACKGROUND The functional survival time of long-lasting insecticidal nets (LLINs), which varies across different field contexts, is critical for the successful prevention of malaria transmission. However, there is limited data on LLIN durability in field settings in Ethiopia. METHODS A three-year longitudinal study was conducted to monitor attrition, physical integrity, and bio-efficacy and residual chemical concentration of LLINs in four regions in Ethiopia. World Health Organization (WHO) guidelines were used to determine sample size, measure physical integrity, and calculate attrition rates, and functional survival time. Yearly bio-efficacy testing was done on randomly selected LLINs. An excel tool developed by vector works project was used to calculate the median functional survival time of the LLINs. Predictors of functional survival were identified by fitting binary and multivariate cox proportional hazards model. RESULTS A total of 3,396 LLINs were included in the analysis. A total of 3,396 LLINs were included in the analysis. By the end of 36 months, the proportion of LLINs functionally surviving was 12.9% [95% confidence interval (CI) 10.5, 15.6], the rates of attrition due to physical damage and repurposing were 48.8% [95% confidence interval (CI) 45.0, 52.6] and 13.8% [95% confidence interval (CI) 11.6, 14.6], respectively. The estimated median functional survival time was 19 months (95%CI 17, 21). Factors associated with shorter functional survival time include being in a low malaria transmission setting [Adjusted Hazards Ratio (AHR) (95%CI) 1.77 (1.22, 2.55)], rural locations [AHR (95%CI) 1.83 (1.17, 2.84)], and in a room where cooking occurs [AHR (95%CI) 1.28 (1.05, 1.55)]. Bioassay tests revealed that 95.3% (95%CI 86.4, 98.5) of the LLINs met the WHO criteria of bio-efficacy after 24 months of distribution. CONCLUSION The LLIN survival time was shorter than the expected three years due to high attrition rates and rapid loss of physical integrity. National malaria programmes may consider, procuring more durable LLINs, educating communities on how to prevent damage of LLINs, and revising the current three-year LLIN distribution schedule to ensure sufficient protection is provided by LLINs against malaria transmission. While this paper contributes to the understanding of determinants impacting functional survival, further research is needed to understand factors for the rapid attrition rates and loss of physical integrity of LLINs in field settings.
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Affiliation(s)
- Honelgn Nahusenay Hiruy
- Department of Epidemiology and Biostatistics, Addis Continental Institute of Public Health, Addis Ababa, Ethiopia
| | - Seth R Irish
- U.S. President's Malaria Initiative, Entomology Branch, U.S. Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | - Semira Abdelmenan
- Department of Epidemiology and Biostatistics, Addis Continental Institute of Public Health, Addis Ababa, Ethiopia.
| | - Yonas Wuletaw
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Ayele Zewde
- Department of Global Health and Policy, Addis Continental Institute of Public Health, Addis Ababa, Ethiopia
| | - Adugna Woyessa
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Mebrahtom Haile
- Ethiopia Federal Ministry of Health, National Malaria Elimination Program, Addis Ababa, Ethiopia
| | - Sheleme Chibsa
- U.S. President's Malaria Initiative, USA Agency for International Development, Addis Ababa, Ethiopia
| | - Lena Lorenz
- U.S. President's Malaria Initiative, USA Agency for International Development, Addis Ababa, Ethiopia
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
- Ifakara Health Institute, Dar-Es-Salaam, Tanzania
- College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, Scotland
| | - Alemayehu Worku
- Department of Epidemiology and Biostatistics, Addis Continental Institute of Public Health, Addis Ababa, Ethiopia
| | - Josh Yukich
- Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Yemane Berhane
- Department of Epidemiology and Biostatistics, Addis Continental Institute of Public Health, Addis Ababa, Ethiopia
| | - Joseph Keating
- Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
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Bio-efficacy, physical integrity, use and attrition of long-lasting insecticidal nets under operational conditions for malaria prevention in Ghana. PLoS One 2022; 17:e0275825. [PMID: 36240161 PMCID: PMC9565380 DOI: 10.1371/journal.pone.0275825] [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: 09/13/2021] [Accepted: 09/23/2022] [Indexed: 11/05/2022] Open
Abstract
Background Malaria remains a public health challenge in endemic countries of the world. The use of Long-lasting Insecticidal Nets (LLINs) is one of the major ways of malaria vector control. Recent evidence however suggests some LLINs are unable to maintain their effectiveness over their useful life span. This study assessed the bio-efficacy, physical integrity, use and attrition at 6 and 12-months post-distribution of LLINs (LifeNet). Methods Following a mass distribution of LLINs in the West Mamprusi District of the North-East region of Ghana in 2018, a total of 147 LLINs were sampled for physical integrity and attrition assessment using hole size and the number of holes as a measure of the proportionate hole index (pHI). Bioassays were conducted on sixty randomly selected LLINs using the WHO guidelines for bio-efficacy testing (cone tests), (20 each at baseline, midline and endline) over a one-year study period. Bed net ownership and use as well as malaria vector resistance status were also assessed. Results Findings indicate high bio-efficacy of approximately 100% average mortalities of mosquitoes at baseline, 6-months and 12-months post-distribution. A small proportion of LLINs (0.8% and 5.6% at the 6 and 12-months surveys respectively) were damaged beyond maintenance while 62.4% and 62.7% of LLINs were used the night before the survey for 6 and 12-months post-distribution respectively. Households with electricity were less likely to use LLINs compared to those without electricity (P-value = 0.016, OR = 0.39). There were 20 fewer LLINs recovered at the 12-months relative to the 6-months resulting in 14.3% attrition rate. Susceptibility testing showed high pyrethroid and organochlorine resistance (18%, 67.5% and 3.8%) to local malaria vectors respectively), whereas organophosphates and carbamates recorded vector susceptibility of 100% for pirimiphos-methyl and 98.7% for bendiocarb. Conclusion Biological efficacy, physical integrity and net attrition during the study period were in conformity with respect to the WHOPES one year net use. LLINs remained effective after one-year of usage. Net ownership was high in the study households. There should be continuous and regular distribution campaigns to maintain high coverage.
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Diouf EH, Diouf M, Dieme C, Swamidoss I, Ngom EHM, Senghor MW, Mbaye M, Konaté A, Coulibaly Y, Tine D, Dia I, Dotson EM, Faye O, Konaté L. Evaluation of the residual efficacy and physical durability of five long-lasting insecticidal nets (LLINs) in Senegal. Malar J 2022; 21:210. [PMID: 35780153 PMCID: PMC9250169 DOI: 10.1186/s12936-022-04230-6] [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: 03/12/2022] [Accepted: 06/06/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The preventive and curative strategies of malaria are based on promoting the use of long-lasting insecticidal nets (LLINs) and treating confirmed cases with artemisinin-based combination therapy. These strategies have led to a sharp decline in the burden of malaria, which remains a significant public health problem in sub-Saharan countries. The objective of this study was to determine and compare the residual efficacy of LLINs recommended by the World Health Organization. METHODS The study was conducted in six villages in two sites in Senegal located in the Sahelo-Sudanian area of the Thiès region, 70 km from Dakar and in Mbagame, a semi-urban zone in the Senegal River Valley. A census was conducted of all sleeping places in each household to be covered by LLINs. Five brands of LLIN were distributed, and every six months, retention rates, net use, maintenance, physical integrity, insecticide chemical content, and biological efficacy were examined for each type of LLIN. RESULTS A total of 3012 LLINs were distributed in 1249 households in both sites, with an average coverage rate of 94% (95% CI 92.68-95.3). After 36 months, the average retention rate was 12.5% and this rate was respectively 20.5%, 15.1%, 10%, 7%, and 3% for Olyset Net®, Dawa Plus® 2.0, PermaNet® 2.0, NetProtect® and Life Net®, respectively. The proportion of LLINs with holes and the average number of holes per mosquito net increased significantly during each follow-up, with a large predominance of size 1 (small) holes for all types of LLINs distributed. During the three-year follow-up, bioassay mortality rates of a susceptible strain of insectary reared Anopheles coluzzii decreased in the following net types: in Dawa Plus® 2.0 (100% to 51.7%), PermaNet® 2.0 (96.6% to 83%), and Olyset Net® (96.6% to 33.3%). Mortality rates remained at 100% in Life Net® over the same time period. After 36 months, the average insecticide content per brand of LLIN decreased by 40.9% for Dawa Plus® 2.0, 31% for PermaNet® 2.0, 39.6% for NetProtect® and 51.9% for Olyset Net® and 40.1% for Life Net. CONCLUSIONS Although some net types retained sufficient insecticidal activity, based on all durability parameters measured, none of the net types survived longer than 2 years.
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Affiliation(s)
- El Hadji Diouf
- Laboratoire d'Ecologie Vectorielle et Parasitaire, Département de Biologie Animal, Faculté Des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Sénégal.
| | - Mbaye Diouf
- Laboratoire d'Ecologie Vectorielle et Parasitaire, Département de Biologie Animal, Faculté Des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Sénégal
| | - Constentin Dieme
- Laboratoire d'Ecologie Vectorielle et Parasitaire, Département de Biologie Animal, Faculté Des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Sénégal
| | - Isabel Swamidoss
- Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and Prevention, Atlanta, GA, USA
| | | | - Massila Wagué Senghor
- Laboratoire d'Ecologie Vectorielle et Parasitaire, Département de Biologie Animal, Faculté Des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Sénégal
| | - Modou Mbaye
- Laboratoire de Télédétection Appliquée, LTA/IST/FST/UCAD, Dakar, Sénégal
| | - Abdoulaye Konaté
- Laboratoire d'Ecologie Vectorielle et Parasitaire, Département de Biologie Animal, Faculté Des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Sénégal
| | - Youssouph Coulibaly
- Laboratoire d'Ecologie Vectorielle et Parasitaire, Département de Biologie Animal, Faculté Des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Sénégal
| | - Dome Tine
- Laboratoire de Télédétection Appliquée, LTA/IST/FST/UCAD, Dakar, Sénégal
| | | | - Ellen Marie Dotson
- Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and Prevention, Atlanta, GA, USA
| | - Ousmane Faye
- Laboratoire d'Ecologie Vectorielle et Parasitaire, Département de Biologie Animal, Faculté Des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Sénégal
| | - Lassana Konaté
- Laboratoire d'Ecologie Vectorielle et Parasitaire, Département de Biologie Animal, Faculté Des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Sénégal
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9
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Madumla EP, Moore SJ, Moore J, Mbuba E, Mbeyela EM, Kibondo UA, C S, Mmbaga, Kobe D, Baraka J, Msellemu D, Swai JK, Mboma ZM, Odufuwa OG. "In starvation, a bone can also be meat": a mixed methods evaluation of factors associated with discarding of long-lasting insecticidal nets in Bagamoyo, Tanzania. Malar J 2022; 21:101. [PMID: 35331242 PMCID: PMC8944021 DOI: 10.1186/s12936-022-04126-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 03/17/2022] [Indexed: 11/27/2022] Open
Abstract
Background Between 2000 and 2019, more than 1.8 billion long-lasting insecticidal nets (LLINs) were distributed in Africa. While the insecticidal durability of LLINs is around 3 years, nets are commonly discarded 2 years post distribution. This study investigated the factors associated with the decision of users to discard LLINs. Methods A mixed-method sequential explanatory approach using a structured questionnaire followed by focus group discussions (FGDs) to collect information on experiences, views, reasons, how and when LLINs are discarded. Out of 6,526 households that responded to the questionnaire of LLINs durability trial, 160 households were randomly selected from the households in four villages in Bagamoyo Tanzania for FGDs but only 155 households participated in the FGDs. Five of the household representatives couldn’t participate due to unexpected circumstances. A total of sixteen FGDs each comprising of 8–10 adults were conducted; older women (40–60 years), older men (40–60 years), younger women (18–39 years), younger men (18–39 years). During the FGDs, participants visually inspected seven samples of LLINs that were “too-torn” based on Proportionate Hole Index recommended by the World Health Organization (WHO) guidelines on LLIN testing, the nets were brought to the discussion and participants had to determine if such LLINs were to be kept or discarded. The study assessed responses from the same participants that attended FGD and also responded to the structured questionnaire, 117 participants fulfilled the criteria, thus data from only 117 participants are analysed in this study. Results In FGDs, integrity of LLIN influenced the decision to discard or keep a net. Those of older age, women, and householders with lower income were more likely to classify a WHO “too-torn” net as “good”. The common methods used to discard LLINs were burning and burying. The findings were seen in the quantitative analysis. For every additional hole, the odds of discarding a WHO “too-torn” LLIN increased [OR = 1.05 (95%CI (1.04–1.07)), p < 0.001]. Younger age group [OR = 4.97 (95%CI (3.25–7.32)), p < 0.001], male-headed households [OR = 6.85 (95%CI (4.44 –10.59)), p < 0.001], and wealthy households [OR = 3.88 (95%CI (2.33–6.46)), p < 0.001] were more likely to discard LLINs. Conclusion Integrity of LLIN was the main determinant for discarding or keeping LLINs and the decision to discard the net is associated with socioeconomic status of the household, and the age and gender of respondents. WHO “too torn” nets are encouraged to be used instead of none until replacement, and disposal of nets should be based on recommendation. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04126-5.
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Affiliation(s)
- Edith P Madumla
- Vector Control Product Testing Unit, Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania. .,Nelson Mandela African Institution of Science and Technology, Tengeru, Arusha, Tanzania.
| | - Sarah J Moore
- Vector Control Product Testing Unit, Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania.,Nelson Mandela African Institution of Science and Technology, Tengeru, Arusha, Tanzania.,Vector Biology Unit, Epidemiology and Public Health Department, Swiss Tropical and Public Health Institute, Kreuzstrasse 2, Allschwil, 4123, Basel, Switzerland.,University of Basel, St. Petersplatz 1, CH-4002, Basel, Switzerland
| | - Jason Moore
- Vector Control Product Testing Unit, Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania.,Vector Biology Unit, Epidemiology and Public Health Department, Swiss Tropical and Public Health Institute, Kreuzstrasse 2, Allschwil, 4123, Basel, Switzerland
| | - Emmanuel Mbuba
- Vector Control Product Testing Unit, Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania.,Vector Biology Unit, Epidemiology and Public Health Department, Swiss Tropical and Public Health Institute, Kreuzstrasse 2, Allschwil, 4123, Basel, Switzerland.,University of Basel, St. Petersplatz 1, CH-4002, Basel, Switzerland
| | - Edgar M Mbeyela
- Vector Control Product Testing Unit, Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Ummi A Kibondo
- Vector Control Product Testing Unit, Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania
| | | | - Mmbaga
- Vector Control Product Testing Unit, Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Dickson Kobe
- Vector Control Product Testing Unit, Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Jitihada Baraka
- Vector Control Product Testing Unit, Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Daniel Msellemu
- Vector Control Product Testing Unit, Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania.,Vector Biology Unit, Epidemiology and Public Health Department, Swiss Tropical and Public Health Institute, Kreuzstrasse 2, Allschwil, 4123, Basel, Switzerland.,University of Basel, St. Petersplatz 1, CH-4002, Basel, Switzerland
| | - Johnson K Swai
- Vector Control Product Testing Unit, Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Zawadi M Mboma
- Vector Control Product Testing Unit, Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Olukayode G Odufuwa
- Vector Control Product Testing Unit, Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania.,Vector Biology Unit, Epidemiology and Public Health Department, Swiss Tropical and Public Health Institute, Kreuzstrasse 2, Allschwil, 4123, Basel, Switzerland.,London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
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10
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Kumoji E'K, Awantang GN, Toso M, Kamara D, Bleu T, Lahai W, Sillah-Kanu M, Dosso A, Achu D, Babalola S. Ideational factors associated with net care behaviour: a multi-country analysis. Malar J 2022; 21:53. [PMID: 35177086 PMCID: PMC8851768 DOI: 10.1186/s12936-022-04053-5] [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: 08/04/2021] [Accepted: 01/17/2022] [Indexed: 11/12/2022] Open
Abstract
Background Malaria is endemic to sub-Saharan African countries. Mass and routine distribution, promotion, and use of ITNs are critical components of malaria prevention programmes. Correct and consistent use of insecticide-treated mosquito nets (ITN) is an effective strategy for malaria prevention. To extend bed-net lifespan, the World Health Organization recommends folding or tying up ITNs when they are not in use. This study analyses factors associated with net care practices in three African countries. Methods Researchers collected household data nationwide in Côte d’Ivoire, from the North and Far North regions of Cameroon, and from Port Loko and Bo districts in Sierra Leone, between 2018 and 2019. The dependent variable was respondents reporting that they fold or tie up their nets. The study adjusted for selected sociodemographic, ideational (psychosocial), and household variables using multilevel models. The analysis was limited to women of reproductive age and their male spouses/partners from households with at least one ITN: 2,940 respondents in Cameroon, 6,105 in Côte d’Ivoire, and 2,730 in Sierra Leone. Results Among respondents, 50.2% in Cameroon, 52.0% in Côte d’Ivoire and 75.6% in Sierra Leone reported folding or tying up their net when it was not in use. In all three countries, the data showed significant clustering at both household and community levels, indicating the influence of factors operating at these levels on net-care behaviour. The odds of reporting the behaviour varied significantly by geographic unit in each country. Consistent use of nets was strongly correlated with net-care behaviour. Furthermore, five ideational variables were positively associated with the outcome behaviour in all three countries: positive attitude towards net care, perceived susceptibility for malaria, response-efficacy of ITNs, perceived self-efficacy for net use, and the perception that net use was a community norm. Additional significant ideational variables included positive attitudes towards net use (Cameroon and Côte d’Ivoire), perceived severity of malaria (Côte d’Ivoire), and interpersonal communication about malaria (Côte d’Ivoire). Conclusions The study identified ideational variables associated with recommended net-care practice. Programme efforts designed to promote net-care practices and extend average lifespan of ITNs may be more effective if they emphasize positive attitudes towards net care, perceived susceptibility of malaria infection, response-efficacy of ITNs, perceived self-efficacy for net use, and promote net-care behaviour as a positive community norm. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04053-5.
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Affiliation(s)
- E 'Kuor Kumoji
- Johns Hopkins Center for Communication Programs, 111 Market Place, Suite 310, Baltimore, MD, 21202, USA.
| | - Grace N Awantang
- Johns Hopkins Center for Communication Programs, 111 Market Place, Suite 310, Baltimore, MD, 21202, USA
| | - Michael Toso
- Johns Hopkins Center for Communication Programs, 111 Market Place, Suite 310, Baltimore, MD, 21202, USA
| | - Diarra Kamara
- Johns Hopkins Center for Communication Programs, 111 Market Place, Suite 310, Baltimore, MD, 21202, USA
| | - Thérèse Bleu
- Programme National de Lutte Contre Le Paludisme, Abidjan, Côte d'Ivoire
| | - Wani Lahai
- National Malaria Control Program, Ministry of Health and Sanitation, Freetown, Sierra Leone
| | - Musa Sillah-Kanu
- National Malaria Control Program, Ministry of Health and Sanitation, Freetown, Sierra Leone
| | - Abdul Dosso
- Programme National de Lutte Contre Le Paludisme, Abidjan, Côte d'Ivoire
| | - Dorothy Achu
- Programme National de Lutte Contre Le Paludisme Au Cameroun, Yaounde, Cameroon
| | - Stella Babalola
- Johns Hopkins Center for Communication Programs, 111 Market Place, Suite 310, Baltimore, MD, 21202, USA.,Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
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11
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Smith T, Denz A, Ombok M, Bayoh N, Koenker H, Chitnis N, Briet O, Yukich J, Gimnig JE. Incidence and consequences of damage to insecticide-treated mosquito nets in Kenya. Malar J 2021; 20:476. [PMID: 34930254 PMCID: PMC8686568 DOI: 10.1186/s12936-021-03978-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Accepted: 11/10/2021] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Efforts to improve the impact of long-lasting insecticidal nets (LLINs) should be informed by understanding of the causes of decay in effect. Holes in LLINs have been estimated to account for 7-11% of loss in effect on vectorial capacity for Plasmodium falciparum malaria in an analysis of repeated cross-sectional surveys of LLINs in Kenya. This does not account for the effect of holes as a cause of net attrition or non-use, which cannot be measured using only cross-sectional data. There is a need for estimates of how much these indirect effects of physical damage on use and attrition contribute to decay in effectiveness of LLINs. METHODS Use, physical integrity, and survival were assessed in a cohort of 4514 LLINs followed for up to 4 years in Kenya. Flow diagrams were used to illustrate how the status of nets, in terms of categories of use, physical integrity, and attrition, changed between surveys carried out at 6-month intervals. A compartment model defined in terms of ordinary differential equations (ODEs) was used to estimate the transition rates between the categories. Effects of physical damage to LLINs on use and attrition were quantified by simulating counterfactuals in which there was no damage. RESULTS Allowing for the direct effect of holes, the effect on use, and the effect on attrition, 18% of the impact on vectorial capacity was estimated to be lost because of damage. The estimated median lifetime of the LLINs was 2.9 years, but this was extended to 5.7 years in the counterfactual without physical damage. Nets that were in use were more likely to be in a damaged state than unused nets but use made little direct difference to LLIN lifetimes. Damage was reported as the reason for attrition for almost half of attrited nets, but the model estimated that almost all attrited nets had suffered some damage before attrition. CONCLUSIONS Full quantification of the effects of damage will require measurement of the supply of new nets and of household stocks of unused nets, and also of their impacts on both net use and retention. The timing of mass distribution campaigns is less important than ensuring sufficient supply. In the Kenyan setting, nets acquired damage rapidly once use began and the damage led to rapid attrition. Increasing the robustness of nets could substantially increase their lifetime and impact but the impact of LLIN programmes on malaria transmission is ultimately limited by levels of use. Longitudinal analyses of net integrity data from different settings are needed to determine the importance of physical damage to nets as a driver of attrition and non-use, and the importance of frequent use as a cause of physical damage in different contexts.
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Affiliation(s)
- Thomas Smith
- Swiss Tropical and Public Health Institute, 4051, Basel, Switzerland.
- University of Basel, 4001, Basel, Switzerland.
| | - Adrian Denz
- Swiss Tropical and Public Health Institute, 4051, Basel, Switzerland
- University of Basel, 4001, Basel, Switzerland
| | - Maurice Ombok
- Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Nabie Bayoh
- Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | | | - Nakul Chitnis
- Swiss Tropical and Public Health Institute, 4051, Basel, Switzerland
- University of Basel, 4001, Basel, Switzerland
| | - Olivier Briet
- Swiss Tropical and Public Health Institute, 4051, Basel, Switzerland
- University of Basel, 4001, Basel, Switzerland
| | - Joshua Yukich
- Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - John E Gimnig
- Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and Prevention, Atlanta, GA, USA
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12
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Cote CM, Goel V, Muhindo R, Baguma E, Ntaro M, Shook-Sa BE, Reyes R, Staedke SG, Mulogo EM, Boyce RM. Malaria prevalence and long-lasting insecticidal net use in rural western Uganda: results of a cross-sectional survey conducted in an area of highly variable malaria transmission intensity. Malar J 2021; 20:304. [PMID: 34225756 PMCID: PMC8256478 DOI: 10.1186/s12936-021-03835-7] [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: 04/09/2021] [Accepted: 06/27/2021] [Indexed: 11/22/2022] Open
Abstract
Background Long-lasting insecticidal nets (LLINs) remain a cornerstone of malaria control, but strategies to sustain universal coverage and high rates of use are not well-defined. A more complete understanding of context-specific factors, including transmission intensity and access to health facilities, may inform sub-district distribution approaches and tailored messaging campaigns. Methods A cross-sectional survey of 2190 households was conducted in a single sub-county of western Uganda that experiences highly variable malaria transmission intensity. The survey was carried out approximately 3 years after the most recent mass distribution campaign. At each household, study staff documented reported LLIN use and source among children 2 to 10 years of age and performed a malaria rapid diagnostic test. Elevation and distance to the nearest health facility was estimated for each household. Associations between parasite prevalence and LLIN use were estimated from log binomial regression models with elevation and distance to clinic being the primary variables of interest. Results Overall, 6.8% (148 of 2170) of children age 2–10 years of age had a positive RDT result, yielding a weighted estimate of 5.8% (95% confidence interval [CI] 5.4–6.2%). There was substantial variability in the positivity rates among villages, with the highest elevation villages having lower prevalence than lowest-elevation villages (p < .001). Only 64.7% (95% CI 64.0–65.5%) of children were reported to have slept under a LLIN the previous night. Compared to those living < 1 km from a health centre, households at ≥ 2 km were less likely to report the child sleeping under a LLIN (RR 0.86, 95% CI 0.83–0.89, p < .001). Households located farther from a health centre received a higher proportion of LLINs from government distributions compared to households living closer to health centres. Conclusions LLIN use and sourcing was correlated with household elevation and estimated distance to the nearest health facility. The findings suggest that current facility-based distribution strategies are limited in their reach. More frequent mass distribution campaigns and complementary approaches are likely required to maintain universal LLIN coverage and high rates of use among children in rural Uganda. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03835-7.
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Affiliation(s)
- Claire M Cote
- Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Varun Goel
- Department of Geography, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Carolina Population Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Rabbison Muhindo
- Department of Community Health, Mbarara University of Science and Technology, Mbarara, Uganda
| | - Emmanuel Baguma
- Department of Community Health, Mbarara University of Science and Technology, Mbarara, Uganda
| | - Moses Ntaro
- Department of Community Health, Mbarara University of Science and Technology, Mbarara, Uganda
| | - Bonnie E Shook-Sa
- Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Raquel Reyes
- Division of Hospital Medicine, UNC School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | | | - Edgar M Mulogo
- Department of Community Health, Mbarara University of Science and Technology, Mbarara, Uganda
| | - Ross M Boyce
- Department of Community Health, Mbarara University of Science and Technology, Mbarara, Uganda. .,Institute of Global Health and Infectious Diseases, UNC School of Medicine, University of North Carolina at Chapel Hill, 130 Mason Farm Road, CB 7030, Chapel Hill, NC, 27599, USA.
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13
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Maps and metrics of insecticide-treated net access, use, and nets-per-capita in Africa from 2000-2020. Nat Commun 2021; 12:3589. [PMID: 34117240 PMCID: PMC8196080 DOI: 10.1038/s41467-021-23707-7] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 05/12/2021] [Indexed: 02/05/2023] Open
Abstract
Insecticide-treated nets (ITNs) are one of the most widespread and impactful malaria interventions in Africa, yet a spatially-resolved time series of ITN coverage has never been published. Using data from multiple sources, we generate high-resolution maps of ITN access, use, and nets-per-capita annually from 2000 to 2020 across the 40 highest-burden African countries. Our findings support several existing hypotheses: that use is high among those with access, that nets are discarded more quickly than official policy presumes, and that effectively distributing nets grows more difficult as coverage increases. The primary driving factors behind these findings are most likely strong cultural and social messaging around the importance of net use, low physical net durability, and a mixture of inherent commodity distribution challenges and less-than-optimal net allocation policies, respectively. These results can inform both policy decisions and downstream malaria analyses.
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14
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Lubinda J, Haque U, Bi Y, Shad MY, Keellings D, Hamainza B, Moore AJ. Climate change and the dynamics of age-related malaria incidence in Southern Africa. ENVIRONMENTAL RESEARCH 2021; 197:111017. [PMID: 33766570 DOI: 10.1016/j.envres.2021.111017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 02/27/2021] [Accepted: 03/11/2021] [Indexed: 06/12/2023]
Abstract
In the last decade, many malaria-endemic countries, like Zambia, have achieved significant reductions in malaria incidence among children <5 years old but face ongoing challenges in achieving similar progress against malaria in older age groups. In parts of Zambia, changing climatic and environmental factors are among those suspectedly behind high malaria incidence. Changes and variations in these factors potentially interfere with intervention program effectiveness and alter the distribution and incidence patterns of malaria differentially between young children and the rest of the population. We used parametric and non-parametric statistics to model the effects of climatic and socio-demographic variables on age-specific malaria incidence vis-à-vis control interventions. Linear regressions, mixed models, and Mann-Kendall tests were implemented to explore trends, changes in trends, and regress malaria incidence against environmental and intervention variables. Our study shows that while climate parameters affect the whole population, their impacts are felt most by people aged ≥5 years. Climate variables influenced malaria substantially more than mosquito nets and indoor residual spraying interventions. We establish that climate parameters negatively impact malaria control efforts by exacerbating the transmission conditions via more conducive temperature and rainfall environments, which are augmented by cultural and socioeconomic exposure mechanisms. We argue that an intensified communications and education intervention strategy for behavioural change specifically targeted at ≥5 aged population where incidence rates are increasing, is urgently required and call for further malaria stratification among the ≥5 age groups in the routine collection, analysis and reporting of malaria mortality and incidence data.
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Affiliation(s)
- Jailos Lubinda
- School of Geography and Environmental Sciences, Ulster University, Coleraine, UK; School of Computing, Engineering and Intelligent Systems, Ulster University, Londonderry, United Kingdom; School of Nursing, Faculty of Life & Health Sciences, Jordanstown, Newtownabbey, United Kingdom.
| | - Ubydul Haque
- Department of Biostatistics and Epidemiology, University of North Texas Health Science Centre, Fort Worth, TX, 76107, USA; Department of Geography, University of Florida, Gainesville, FL, USA; Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Yaxin Bi
- School of Computing, Ulster University, Jordanstown, Newtownabbey, UK
| | | | - David Keellings
- Department of Geography, University of Alabama, Tuscaloosa, AL, USA
| | - Busiku Hamainza
- Ministry of Health, National Malaria Elimination Center, Lusaka, Zambia
| | - Adrian J Moore
- School of Geography and Environmental Sciences, Ulster University, Coleraine, UK
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15
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Evaluation of the durability of long-lasting insecticidal nets in Guatemala. Malar J 2021; 20:219. [PMID: 33990197 PMCID: PMC8120849 DOI: 10.1186/s12936-021-03722-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 04/03/2021] [Indexed: 12/04/2022] Open
Abstract
Background Insecticide-treated bed nets (ITNs) are widely used for the prevention and control of malaria. In Guatemala, since 2006, ITNs have been distributed free of charge in the highest risk malaria-endemic areas and constitute one of the primary vector control measures in the country. Despite relying on ITNs for almost 15 years, there is a lack of data to inform the timely replacement of ITNs whose effectiveness becomes diminished by routine use. Methods The survivorship, physical integrity, insecticide content and bio-efficacy of ITNs were assessed through cross-sectional surveys conducted at 18, 24 and 32 months after a 2012 distribution of PermaNet® 2.0 in a malaria focus in Guatemala. A working definition of ‘LLIN providing adequate protection’ was developed based on the combination of the previous parameters and usage of the net. A total of 988 ITNs were analysed (290 at 18 months, 349 at 24 months and 349 at 32 months). Results The functional survivorship of bed nets decreased over time, from 92% at 18 months, to 81% at 24 months and 69% at 32 months. Independent of the time of the survey, less than 80% of the bed nets that were still present in the household were reported to have been used the night before. The proportion of bed nets categorized as “in good condition” per World Health Organization (WHO) guidelines of the total hole surface area, diminished from 77% to 18 months to 58% at 32 months. The portion of ITNs with deltamethrin concentration less than 10 mg/m2 increased over time. Among the bed nets for which bioassays were conducted, the percentage that met WHO criteria for efficacy dropped from 90% to 18 months to 52% at 32 months. The proportion of long-lasting insecticidal nets (LLINs) providing adequate protection was 38% at 24 months and 21% at 32 months. Conclusions At 32 months, only one in five of the LLINs distributed in the campaign provided adequate protection in terms of survivorship, physical integrity, bio-efficacy and usage. Efforts to encourage the community to retain, use, and properly care for the LLINs may improve their impact. Durability assessments should be included in future campaigns. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03722-1.
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16
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Namuganga JF, Epstein A, Nankabirwa JI, Mpimbaza A, Kiggundu M, Sserwanga A, Kapisi J, Arinaitwe E, Gonahasa S, Opigo J, Ebong C, Staedke SG, Shililu J, Okia M, Rutazaana D, Maiteki-Sebuguzi C, Belay K, Kamya MR, Dorsey G, Rodriguez-Barraquer I. The impact of stopping and starting indoor residual spraying on malaria burden in Uganda. Nat Commun 2021; 12:2635. [PMID: 33976132 PMCID: PMC8113470 DOI: 10.1038/s41467-021-22896-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 04/01/2021] [Indexed: 12/03/2022] Open
Abstract
The scale-up of malaria control efforts has led to marked reductions in malaria burden over the past twenty years, but progress has slowed. Implementation of indoor residual spraying (IRS) of insecticide, a proven vector control intervention, has been limited and difficult to sustain partly because questions remain on its added impact over widely accepted interventions such as bed nets. Using data from 14 enhanced surveillance health facilities in Uganda, a country with high bed net coverage yet high malaria burden, we estimate the impact of starting and stopping IRS on changes in malaria incidence. We show that stopping IRS was associated with a 5-fold increase in malaria incidence within 10 months, but reinstating IRS was associated with an over 5-fold decrease within 8 months. In areas where IRS was initiated and sustained, malaria incidence dropped by 85% after year 4. IRS could play a critical role in achieving global malaria targets, particularly in areas where progress has stalled.
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Affiliation(s)
| | - Adrienne Epstein
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA.
| | - Joaniter I Nankabirwa
- Infectious Diseases Research Collaboration, Kampala, Uganda
- Department of Medicine, Makerere University, College of Health Sciences, Kampala, Uganda
| | - Arthur Mpimbaza
- Infectious Diseases Research Collaboration, Kampala, Uganda
- Child Health and Development Centre, Makerere University, College of Health Sciences, Kampala, Uganda
| | - Moses Kiggundu
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | - James Kapisi
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | | | - Jimmy Opigo
- National Malaria Control Division, Ministry of Health, Kampala, Uganda
| | - Chris Ebong
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | - Josephat Shililu
- US President's Malaria Initiative - VectorLink Uganda Project, Kampala, Uganda
| | - Michael Okia
- US President's Malaria Initiative - VectorLink Uganda Project, Kampala, Uganda
| | - Damian Rutazaana
- National Malaria Control Division, Ministry of Health, Kampala, Uganda
| | | | - Kassahun Belay
- US President's Malaria Initiative, USAID/Uganda Senior Malaria Advisor, Kampala, Uganda
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda
- Department of Medicine, Makerere University, College of Health Sciences, Kampala, Uganda
| | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, CA, USA
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17
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Mboma ZM, Festo C, Lorenz LM, Massue DJ, Kisinza WN, Bradley J, Moore JD, Mandike R, Akim I, Lines J, Overgaard HJ, Moore SJ. The consequences of declining population access to insecticide-treated nets (ITNs) on net use patterns and physical degradation of nets after 22 months of ownership. Malar J 2021; 20:171. [PMID: 33781261 PMCID: PMC8008556 DOI: 10.1186/s12936-021-03686-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 03/05/2021] [Indexed: 11/30/2022] Open
Abstract
Background As insecticide-treated nets (ITNs) wear out and are disposed, some household members are prioritized to use remaining ITNs. This study assessed how nets are allocated within households to individuals of different age categories as ITNs are lost or damaged and as new ITNs are obtained. The study also explored how ITN allocation affects ITN durability. Methods A cross-sectional household survey and ITN durability study was conducted among 2,875 households across Tanzania to determine the proportion of nets that remain protective (serviceable) 22 months after net distribution aiming for universal coverage. Allocation of study nets within houses, and re-allocation of ITNs when new universal replacement campaign (URC) nets arrived in study households in Musoma District, was also assessed. Results Some 57.0% (95% CI 53.9–60.1%) of households had sufficient ITNs for every household member, while 84.4% (95% CI 82.4–86.4%) of the population had access to an ITN within their household (assuming 1 net covers every 2 members). In households with sufficient nets, 77.5% of members slept under ITNs. In households without sufficient nets, pregnant women (54.6%), children < 5 years (45.8%) and adults (42.1%) were prioritized, with fewer school-age children 5–14 years (35.9%), youths 15–24 years (28.1%) and seniors > 65 years (32.6%) sleeping under ITNs. Crowding (\documentclass[12pt]{minimal}
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\begin{document}$$\ge$$\end{document}≥ 3 people sleeping under nets) was twice as common among people residing in houses without sufficient nets for all age groups, apart from children < 5. Nets were less likely to be serviceable if: \documentclass[12pt]{minimal}
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\begin{document}$$\ge$$\end{document}≥ 3 people slept under them (OR 0.50 (95% CI 0.40–0.63)), or if nets were used by school-age children (OR 0.72 (95% CI 0.56–0.93)), or if the net product was Olyset®. One month after the URC, only 23.6% (95% CI 16.7–30.6%) of the population had access to a URC ITN in Musoma district. Householders in Musoma district continued the use of old ITNs even with the arrival of new URC nets. Conclusion Users determined the useful life of ITNs and prioritized pregnant women and children < 5 to serviceable ITNs. When household net access declines, users adjust by crowding under remaining nets, which further reduces ITN lifespan. School-age children that commonly harbour gametocytes that mediate malaria transmission are compelled to sleep under unserviceable nets, crowd under nets or remain uncovered. However, they were accommodated by the arrival of new nets. More frequent ITN delivery through the school net programme in combination with mass distribution campaigns is essential to maximize ITN effectiveness. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03686-2.
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Affiliation(s)
- Zawadi M Mboma
- Ifakara Health Institute, Dar es Salaam, Tanzania. .,Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK.
| | | | - Lena M Lorenz
- Ifakara Health Institute, Dar es Salaam, Tanzania.,Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK.,College of Medicine and Veterinary Medicine, University of Edinburgh, Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
| | - Dennis J Massue
- Vector Control Product Testing Unit, Ifakara Health Institute, Ifakara, Tanzania.,Epidemiology and Public Health Department, Swiss Institute of Tropical and Public Health, Soccinstrase 57, 4002, Basel, Switzerland.,University of Basel, Petersplatz 1, 4003, Basel, Switzerland.,University of Dar Es Salaam, Mbeya College of Health and Allied Sciences, Box 608, Mbeya, Tanzania
| | - William N Kisinza
- National Institute for Medical Research, Amani Research Centre, Muheza, Tanga, Tanzania
| | - John Bradley
- MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Jason D Moore
- Vector Control Product Testing Unit, Ifakara Health Institute, Ifakara, Tanzania.,Epidemiology and Public Health Department, Swiss Institute of Tropical and Public Health, Soccinstrase 57, 4002, Basel, Switzerland
| | - Renata Mandike
- Ministry of Health and Social Welfare, National Malaria Control Programme, Dar-es-Salaam, Tanzania
| | - Ikupa Akim
- Epidemiology and Public Health Department, Swiss Institute of Tropical and Public Health, Soccinstrase 57, 4002, Basel, Switzerland
| | - Jo Lines
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Hans J Overgaard
- Faculty of Science and Technology, Norwegian University of Life Sciences, P.O. Box 5003, 1432, Ås, Norway.,Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Sarah J Moore
- Vector Control Product Testing Unit, Ifakara Health Institute, Ifakara, Tanzania.,Epidemiology and Public Health Department, Swiss Institute of Tropical and Public Health, Soccinstrase 57, 4002, Basel, Switzerland.,University of Basel, Petersplatz 1, 4003, Basel, Switzerland
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18
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Karl S, Katusele M, Freeman TW, Moore SJ. Quality Control of Long-Lasting Insecticidal Nets: Are We Neglecting It? Trends Parasitol 2021; 37:610-621. [PMID: 33773912 DOI: 10.1016/j.pt.2021.03.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/25/2021] [Accepted: 03/05/2021] [Indexed: 11/16/2022]
Abstract
Over 2.2 billion long-lasting insecticidal nets (LLINs) for malaria control have been delivered to recipient countries. LLINs are the largest single item in the global malaria control budget. To be eligible for donor-funded procurement and distribution schemes, LLIN products must attain and retain World Health Organization (WHO) prequalification status by passing safety, quality, and efficacy benchmarks. Predelivery inspections further test product quality before distribution. We have shown that, despite these quality-assurance measures, substandard LLINs were distributed in Papua New Guinea (PNG) for at least 6 years (2013-2019). Other countries may have received similar LLINs. Here, we discuss the most important weaknesses of the current LLIN quality-assurance framework that have made this possible.
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Affiliation(s)
- Stephan Karl
- Australian Institute of Tropical Health and Medicine, James Cook University, 1/14-88 McGregor Road, Smithfield, QLD, 4870, Australia; Vector Borne Disease Research Unit, PNG Institute of Medical Research, P.O. Box 378, Madang, 511, Madang Province, Papua New Guinea.
| | - Michelle Katusele
- Vector Borne Disease Research Unit, PNG Institute of Medical Research, P.O. Box 378, Madang, 511, Madang Province, Papua New Guinea
| | - Timothy W Freeman
- Rotarians Against Malaria, P.O. Box 3686, Port Moresby, 121, NCD, Papua New Guinea
| | - Sarah J Moore
- Vector Control Product Testing Unit, Ifakara Health Institute, P.O. Box 74, Bagamoyo, Tanzania; Swiss Tropical and Public Health Institute, Vector Biology Unit, Department of Epidemiology and Public Health Socinstrasse, 57, CH-4002 Basel, Switzerland; University of Basel, Petersplatz 1, 4001, Basel, Switzerland
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19
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Villalta EL, Soto Bravo AM, Vizcaino L, Dzuris N, Delgado M, Green M, Smith SC, Lenhart A, Macedo de Oliveira A. Evaluation of the durability and use of long-lasting insecticidal nets in Nicaragua. Malar J 2021; 20:106. [PMID: 33608024 PMCID: PMC7893764 DOI: 10.1186/s12936-021-03604-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 01/22/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Vector control for malaria prevention relies most often on the use of insecticide-treated bed net (ITNs) and indoor residual spraying. Little is known about the longevity of long-lasting insecticidal nets (LLINs) in the Americas. The physical integrity and insecticide retention of LLINs over time were monitored after a bed net distribution campaign to assess community practices around LLIN care and use in Waspam, northeastern Nicaragua. METHODS At least 30 nets were collected at 6, 12, 24, and 36 months post distribution. Physical integrity was measured by counting holes and classifying nets into categories (good, damaged, and too torn) depending on a proportionate hole index (pHI). Insecticide bioefficacy was assessed using cone bioassays, and insecticide content measured using a cyanopyrethroid field test (CFT). RESULTS At 6 months, 87.3 % of LLINs were in good physical condition, while by 36 months this decreased to 20.6 %, with 38.2 % considered 'too torn.' The median pHI increased from 7 at the 6-month time point to 480.5 by 36 months. After 36 months of use, median mortality in cone bioassays was 2 % (range: 0-6 %) compared to 16 % (range: 2-70 %) at 6 months. There was a decrease in the level of deltamethrin detected on the surface of the LLINs with 100 % of tested LLINs tested at 12 months and 24 months crossing the threshold for being considered a failed net by CFT. CONCLUSIONS This first comprehensive analysis of LLIN durability in Central America revealed rapid loss of chemical bioefficacy and progressive physical damage over a 36-month period. Use of these findings to guide future LLIN interventions in malaria elimination settings in Nicaragua, and potentially elsewhere in the Americas, could help optimize the successful implementation of vector control strategies.
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Affiliation(s)
| | | | - Lucrecia Vizcaino
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, USA
| | - Nicole Dzuris
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, USA
| | - Marco Delgado
- Entomología Médica, Ministerio de Salud, Managua, Nicaragua
| | - Michael Green
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, USA
| | - Stephen C Smith
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, USA
| | - Audrey Lenhart
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, USA
| | - Alexandre Macedo de Oliveira
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, USA.
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20
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Wheldrake A, Guillemois E, Arouni H, Chetty V, Russell SJ. Textile testing to assess the resistance to damage of long-lasting insecticidal nets for malaria control and prevention. Malar J 2021; 20:47. [PMID: 33468152 PMCID: PMC7816374 DOI: 10.1186/s12936-020-03571-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 12/24/2020] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND LLINs are susceptible to forming holes within a short time in use, compromising their ability to provide long-term physical protection against insect-borne vectors of disease. Mechanical damage is known to be responsible for the majority of holes, with most being the result of snagging, tearing, hole enlargement, abrasion and seam failure, which can readily occur during normal household use. To enable an assessment of the ability of LLINs to resist such damage prior to distribution, a new suite of testing methods was developed to reflect the main damage mechanisms encountered during normal use of LLINs. METHODS Four existing BS EN and ISO standards used by the textile industry were adapted to determine the ability of LLINs to resist the most common mechanisms of real-world damage experienced in the field. The new suite comprised tests for snag strength (BS 15,598:2008), bursting strength (ISO 13938-2:1999), hole enlargement resistance (BS 3423-38:1998), abrasion resistance (ISO 12947-1:1998) and new guidance around the seam construction of LLINs. Fourteen different LLINs were tested using the new suite of tests to evaluate their resistance to damage. RESULTS The resistance to mechanical damage of LLINs is not the same, even when the bursting strength values are comparable. Differences in performance between LLINs are directly related to the fabric design specifications, including the knitted structure and constituent yarns. The differences in performance do not primarily relate to what polymer type the LLIN is made from. LLINs made with a Marquisette knitted structure produced the highest snag strength and lowest hole enlargement values. By contrast, LLINs made with a traverse knitted structure exhibited low snag strength values when compared at the same mesh count. CONCLUSIONS Prequalification of LLINs should consider not only insecticidal performance, but also inherent resistance to mechanical damage. This is critical to ensuring LLINs are fit for purpose prior to distribution, and are capable of remaining in good physical condition for longer. The new suite of test methods enables the performance of LLINs to be assessed and specified in advance of distribution and can be used to establish minimum performance standards. Implementation of these testing methods is therefore recommended.
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Affiliation(s)
- Amy Wheldrake
- Nonwovens Innovation & Research Institute Ltd, 169 Meanwood Road, Leeds, LS7 1SR, West Yorkshire, UK
| | - Estelle Guillemois
- Nonwovens Innovation & Research Institute Ltd, 169 Meanwood Road, Leeds, LS7 1SR, West Yorkshire, UK
| | - Hamidreza Arouni
- Nonwovens Innovation & Research Institute Ltd, 169 Meanwood Road, Leeds, LS7 1SR, West Yorkshire, UK
| | - Vera Chetty
- Nonwovens Innovation & Research Institute Ltd, 169 Meanwood Road, Leeds, LS7 1SR, West Yorkshire, UK
| | - Stephen J Russell
- Nonwovens Innovation & Research Institute Ltd, 169 Meanwood Road, Leeds, LS7 1SR, West Yorkshire, UK.
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21
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Wheldrake A, Guillemois E, Chetty V, Kilian A, Russell SJ. Development of a single resistance to damage metric for mosquito nets related to physical integrity in the field. Malar J 2021; 20:46. [PMID: 33468151 PMCID: PMC7816509 DOI: 10.1186/s12936-020-03566-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 12/22/2020] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND In common with the majority of personal protective equipment and healthcare products, the ability for long-lasting insecticidal nets (LLINs) to remain in good physical condition during use is a key factor governing fitness for purpose and serviceability. The inherent ability of a product to resist physical deterioration should be known in advance of it being used to ensure it has maximum value to both the end-user and procurer. The objective of this study was to develop a single performance metric of resistance to damage (RD) that can be applied to any LLIN product prior to distribution. METHODS Algorithms to calculate RD values were developed based on consideration of both human factors and laboratory testing data. Quantitative reference forces applied to LLINs by users during normal use were determined so that aspirational performance levels could be established. The ability of LLINs to resist mechanical damage was assessed based on a new suite of textile tests, reflecting actual mechanisms of physical deterioration during normal household use. These tests quantified the snag strength, bursting strength, abrasion resistance and resistance to hole enlargement. Sixteen different unused LLINs were included in the analysis. The calculated RD values for all LLINs and the corresponding physical integrity data for the same nets retrieved from the field (up to 3 years of use) were then compared. RESULTS On a RD scale of 0 (lowest resistance) - 100 (highest resistance), only six of the sixteen LLINs achieved an RD value above 50. No current LLIN achieved the aspirational level of resistance to damage (RD = 100), suggesting that product innovation is urgently required to increase the RD of LLINs. LLINs with higher RD values were associated with lower hole damage (PHI) in the field when adjusted for normal use conditions. CONCLUSIONS The RD value of any LLIN product can be determined prior to distribution based on the developed algorithms and laboratory textile testing data. Generally, LLINs need to achieve higher RD values to improve their ability to resist hole formation during normal use. Innovation in LLIN product design focused on the textile material should be actively encouraged and is urgently needed to close the performance gap.
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Affiliation(s)
- Amy Wheldrake
- Nonwovens Innovation & Research Institute Ltd, 169 Meanwood Road, Leeds, LS7 1SR, West Yorkshire, UK
| | - Estelle Guillemois
- Nonwovens Innovation & Research Institute Ltd, 169 Meanwood Road, Leeds, LS7 1SR, West Yorkshire, UK
| | - Vera Chetty
- Nonwovens Innovation & Research Institute Ltd, 169 Meanwood Road, Leeds, LS7 1SR, West Yorkshire, UK
| | | | - Stephen J Russell
- Nonwovens Innovation & Research Institute Ltd, 169 Meanwood Road, Leeds, LS7 1SR, West Yorkshire, UK.
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22
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Near-term climate change impacts on sub-national malaria transmission. Sci Rep 2021; 11:751. [PMID: 33436862 PMCID: PMC7803742 DOI: 10.1038/s41598-020-80432-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 12/17/2020] [Indexed: 01/29/2023] Open
Abstract
The role of climate change on global malaria is often highlighted in World Health Organisation reports. We modelled a Zambian socio-environmental dataset from 2000 to 2016, against malaria trends and investigated the relationship of near-term environmental change with malaria incidence using Bayesian spatio-temporal, and negative binomial mixed regression models. We introduced the diurnal temperature range (DTR) as an alternative environmental measure to the widely used mean temperature. We found substantial sub-national near-term variations and significant associations with malaria incidence-trends. Significant spatio-temporal shifts in DTR/environmental predictors influenced malaria incidence-rates, even in areas with declining trends. We highlight the impact of seasonally sensitive DTR, especially in the first two quarters of the year and demonstrate how substantial investment in intervention programmes is negatively impacted by near-term climate change, most notably since 2010. We argue for targeted seasonally-sensitive malaria chemoprevention programmes.
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23
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Kilian A, Obi E, Mansiangi P, Abílio AP, Haji KA, Guillemois E, Chetty V, Wheldrake A, Blaufuss S, Olapeju B, Babalola S, Russell SJ, Koenker H. Correlation of textile 'resistance to damage' scores with actual physical survival of long-lasting insecticidal nets in the field. Malar J 2021; 20:29. [PMID: 33413383 PMCID: PMC7792112 DOI: 10.1186/s12936-020-03570-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 12/24/2020] [Indexed: 10/28/2022] Open
Abstract
BACKGROUND Attempts have been made to link procurement of long-lasting insecticidal nets (LLIN) not only to the price but also the expected performance of the product. However, to date it has not been possible to identify a specific textile characteristic that predicts physical durability in the field. The recently developed resistance to damage (RD) score could provide such a metric. This study uses pooled data from durability monitoring to explore the usefulness of the RD methodology. METHODS Data from standardized, 3-year, prospective LLIN durability monitoring for six LLIN brands in 10 locations and four countries involving 4672 campaign LLIN were linked to the RD scores of the respective LLIN brands. The RD score is a single quantitative metric based on a suite of standardized textile tests which in turn build on the mechanisms of damage to a mosquito net. Potential RD values range from 0 to 100 where 100 represents optimal resistance to expected day-to-day stress during reasonable net use. Survival analysis was set so that risk of failure only started when nets were first hung. Cox regression was applied to explore RD effects on physical survival adjusting for known net use environment variables. RESULTS In a bivariate analysis RD scores showed a linear relationship with physical integrity suggesting that the proportion of LLIN with moderate damage decreased by 3%-points for each 10-point increase of the RD score (p = 0.02, R2 = 0.65). Full adjustment for net care and handling behaviours as well as other relevant determinants and the country of study showed that increasing RD score by 10 points resulted in a 36% reduction of risk of failure to survive in serviceable condition (p < 0.0001). LLINs with RD scores above 50 had an additional useful life of 7 months. CONCLUSIONS This study provides proof of principle that the RD metric can predict physical durability of LLIN products in the field and could be used to assess new products and guide manufacturers in creating improved products. However, additional validation from other field data, particularly for next generation LLIN, will be required before the RD score can be included in procurement decisions for LLINs.
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Affiliation(s)
- Albert Kilian
- PMI VectorWorks Project, Tropical Health LLP, Montagut, Spain.
| | - Emmanuel Obi
- PMI VectorWorks Project, Tropical Health LLP, Abuja, Nigeria
| | - Paul Mansiangi
- Ecole de Santé Publique, Université de Kinshasa, Kinshasa, Democratic Republic of the Congo
| | | | - Khamis Ameir Haji
- Zanzibar Malaria Elimination Programme, Stone Town, Zanzibar, Tanzania
| | | | - Vera Chetty
- Nonwovens Innovation and Research Institute Ltd. (NIRI), Leeds, UK
| | - Amy Wheldrake
- Nonwovens Innovation and Research Institute Ltd. (NIRI), Leeds, UK
| | - Sean Blaufuss
- PMI VectorWorks Project, JHU Center for Communication Programs, Baltimore, MD, USA
| | - Bolanje Olapeju
- PMI VectorWorks Project, JHU Center for Communication Programs, Baltimore, MD, USA
| | - Stella Babalola
- PMI VectorWorks Project, JHU Center for Communication Programs, Baltimore, MD, USA
| | | | - Hannah Koenker
- PMI VectorWorks Project, JHU Center for Communication Programs, Baltimore, MD, USA
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24
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Kilian A, Obi E, Mansiangi P, Abílio AP, Haji KA, Blaufuss S, Olapeju B, Babalola S, Koenker H. Variation of physical durability between LLIN products and net use environments: summary of findings from four African countries. Malar J 2021; 20:26. [PMID: 33413388 PMCID: PMC7791654 DOI: 10.1186/s12936-020-03549-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 12/12/2020] [Indexed: 11/14/2022] Open
Abstract
Background Physical durability of long-lasting-insecticidal nets (LLIN) is an important aspect of the effectiveness of LLIN as a malaria prevention tool, but there is limited data on performance across locations and products. This secondary analysis of data from the VectorWorks project from 10 sites in four African countries involving six LLIN brands provides such data. Methods A total of 4672 campaign nets from 1976 households were recruited into prospective cohort studies 2–6 months after distribution through campaigns and followed for 3 years in Mozambique, Nigeria, DRC and Zanzibar, Tanzania. LLIN products included two 100 denier polyester LLIN (DawaPlus® 2.0, PermaNet® 2.0) distributed in five sites and four 150 denier polyethylene LLIN (Royal Sentry®, MAGNet®, DuraNet©, Olyset™ Net) distributed in five sites. Primary outcome was LLIN survival in serviceable condition and median survival in years. Net use environment and net care variables were collected during four household surveys. Determinants of physical durability were explored by survival analysis and Cox regression models with risk of failure starting with the first hanging of the net. Results Definite outcomes for physical durability were obtained for 75% of study nets. After 31 to 37 months survival in serviceable condition varied between sites by 63 percentage-points, from 17 to 80%. Median survival varied by 3.7 years, from 1.6 to 5.3 years. Similar magnitude of variation was seen for polyethylene and polyester LLIN and for the same brand. Cox regression showed increasing net care attitude in combination with exposure to net related messages to be the strongest explanatory variable of survival. However, differences between countries also remained significant. In contrast, no difference was seen for LLIN material types. Conclusions Variation in net use environment and net care is the main reason for differences in the physical durability of LLIN products in different locations. While some of these factors have been identified to work across countries, other factors remain poorly defined and further investigation is needed in this area. Grouping LLIN brands by similar textile characteristics, such as material or yarn strength, is insufficient to distinguish LLIN product performance suggesting a more differentiated, composite metric is needed.
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Affiliation(s)
- Albert Kilian
- PMI VectorWorks Project, Tropical Health LLP, Montagut, Spain.
| | - Emmanuel Obi
- PMI VectorWorks Project, Tropical Health LLP, Abuja, Nigeria
| | - Paul Mansiangi
- Ecole de Santé Publique, Université de Kinshasa, Kinshasa, Democratic Republic of Congo
| | | | - Khamis Ameir Haji
- Zanzibar Malaria Elimination Programme, Stone Town, Zanzibar, Tanzania
| | - Sean Blaufuss
- PMI VectorWorks Project, JHU Center for Communication Programs, Baltimore, MD, USA
| | - Bolanle Olapeju
- PMI VectorWorks Project, JHU Center for Communication Programs, Baltimore, MD, USA
| | - Stella Babalola
- PMI VectorWorks Project, JHU Center for Communication Programs, Baltimore, MD, USA
| | - Hannah Koenker
- PMI VectorWorks Project, JHU Center for Communication Programs, Baltimore, MD, USA
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25
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Briet O, Koenker H, Norris L, Wiegand R, Vanden Eng J, Thackeray A, Williamson J, Gimnig JE, Fortes F, Akogbeto M, Yadouleton AW, Ombok M, Bayoh MN, Mzilahowa T, Abílio AP, Mabunda S, Cuamba N, Diouf E, Konaté L, Hamainza B, Katebe-Sakala C, Ponce de León G, Asamoa K, Wolkon A, Smith SC, Swamidoss I, Green M, Gueye S, Mihigo J, Morgan J, Dotson E, Craig AS, Tan KR, Wirtz RA, Smith T. Attrition, physical integrity and insecticidal activity of long-lasting insecticidal nets in sub-Saharan Africa and modelling of their impact on vectorial capacity. Malar J 2020; 19:310. [PMID: 32859210 PMCID: PMC7456088 DOI: 10.1186/s12936-020-03383-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 08/19/2020] [Indexed: 11/25/2022] Open
Abstract
Background Long-lasting insecticidal nets (LLINs) are the primary malaria prevention and control intervention in many parts of sub-Saharan Africa. While LLINs are expected to last at least 3 years under normal use conditions, they can lose effectiveness because they fall out of use, are discarded, repurposed, physically damaged, or lose insecticidal activity. The contributions of these different interrelated factors to durability of nets and their protection against malaria have been unclear. Methods Starting in 2009, LLIN durability studies were conducted in seven countries in Africa over 5 years. WHO-recommended measures of attrition, LLIN use, insecticidal activity, and physical integrity were recorded for eight different net brands. These data were combined with analyses of experimental hut data on feeding inhibition and killing effects of LLINs on both susceptible and pyrethroid resistant malaria vectors to estimate the protection against malaria transmission—in terms of vectorial capacity (VC)—provided by each net cohort over time. Impact on VC was then compared in hypothetical scenarios where one durability outcome measure was set at the best possible level while keeping the others at the observed levels. Results There was more variability in decay of protection over time by country than by net brand for three measures of durability (ratios of variance components 4.6, 4.4, and 1.8 times for LLIN survival, use, and integrity, respectively). In some countries, LLIN attrition was slow, but use declined rapidly. Non-use of LLINs generally had more effect on LLIN impact on VC than did attrition, hole formation, or insecticide loss. Conclusions There is much more variation in LLIN durability among countries than among net brands. Low levels of use may have a larger impact on effectiveness than does variation in attrition or LLIN degradation. The estimated entomological effects of chemical decay are relatively small, with physical decay probably more important as a driver of attrition and non-use than as a direct cause of loss of effect. Efforts to maximize LLIN impact in operational settings should focus on increasing LLIN usage, including through improvements in LLIN physical integrity. Further research is needed to understand household decisions related to LLIN use, including the influence of net durability and the presence of other nets in the household.
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Affiliation(s)
- Olivier Briet
- Swiss Tropical and Public Health Institute, 4051, Basel, Switzerland.,University of Basel, 4001, Basel, Switzerland
| | - Hannah Koenker
- PMI VectorWorks, JHU Center for Communication Programs, Baltimore, MD, USA.,Tropical Health LLP, Baltimore, MD, USA
| | - Laura Norris
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Washington, DC, USA.,Bill & Melinda Gates Foundation, Seattle, WA, USA
| | - Ryan Wiegand
- Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and Prevention, Atlanta, GA, USA
| | - Jodi Vanden Eng
- Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and Prevention, Atlanta, GA, USA
| | | | - John Williamson
- Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and Prevention, Atlanta, GA, USA
| | - John E Gimnig
- Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and Prevention, Atlanta, GA, USA
| | - Filomeno Fortes
- National Malaria Control Program (NMCP), Ministry of Health, Luanda, Angola.,Institute of Hygiene and Tropical Medicine, NOVA University Lisbon, Lisbon, Portugal
| | - Martin Akogbeto
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Bénin
| | - Anges W Yadouleton
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Bénin.,Programme National de Lutte contre le Paludisme (PNLP), Ministry of Health, Cotonou, Bénin
| | - Maurice Ombok
- Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - M Nabie Bayoh
- Kenya Medical Research Institute (KEMRI), Kisumu, Kenya.,PMI VectorLink Project, Abt Associates, Lusaka, Zambia
| | - Themba Mzilahowa
- College of Medicine, Malaria Alert Centre, P/Bag 360, Blantyre 3, Malawi
| | - Ana Paula Abílio
- Instituto Nacional de Saúde (INS), Ministério da Saúde, Maputo, Mozambique
| | - Samuel Mabunda
- Instituto Nacional de Saúde (INS), Ministério da Saúde, Maputo, Mozambique.,National Malaria Control Programme (NMCP), Ministry of Health, Maputo, Mozambique
| | - Nelson Cuamba
- Instituto Nacional de Saúde (INS), Ministério da Saúde, Maputo, Mozambique.,National Malaria Control Programme (NMCP), Ministry of Health, Maputo, Mozambique
| | - Elhadji Diouf
- Faculté des Sciences et Techniques (FST), Université Cheikh Anta Diop (UCAD), Dakar, Senegal
| | - Lassana Konaté
- Faculté des Sciences et Techniques (FST), Université Cheikh Anta Diop (UCAD), Dakar, Senegal
| | | | | | - Gabriel Ponce de León
- Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and Prevention, Atlanta, GA, USA
| | - Kwame Asamoa
- Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and Prevention, Atlanta, GA, USA
| | - Adam Wolkon
- Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and Prevention, Atlanta, GA, USA
| | - Stephen C Smith
- Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and Prevention, Atlanta, GA, USA
| | - Isabel Swamidoss
- Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and Prevention, Atlanta, GA, USA
| | - Mike Green
- Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and Prevention, Atlanta, GA, USA
| | - Salam Gueye
- Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and Prevention, Atlanta, GA, USA
| | - Jules Mihigo
- Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and Prevention, Atlanta, GA, USA
| | - Juliette Morgan
- U.S. President's Malaria Initiative, Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and Prevention, Atlanta, GA, USA
| | - Ellen Dotson
- Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and Prevention, Atlanta, GA, USA
| | - Allen S Craig
- U.S. President's Malaria Initiative, Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and Prevention, Atlanta, GA, USA
| | - Kathrine R Tan
- Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and Prevention, Atlanta, GA, USA
| | - Robert A Wirtz
- Division of Parasitic Diseases and Malaria, Centers for Disease Control (CDC) and Prevention, Atlanta, GA, USA
| | - Tom Smith
- Swiss Tropical and Public Health Institute, 4051, Basel, Switzerland. .,University of Basel, 4001, Basel, Switzerland.
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Santos EM, Coalson JE, Munga S, Agawo M, Jacobs ET, Klimentidis YC, Hayden MH, Ernst KC. "After those nets are torn, most people use them for other purposes": an examination of alternative bed net use in western Kenya. Malar J 2020; 19:272. [PMID: 32727452 PMCID: PMC7390200 DOI: 10.1186/s12936-020-03342-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 07/17/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Alternative long-lasting insecticidal net (LLIN) use for purposes other than sleeping protection from mosquitoes is widely debated as a limitation to successful malaria control efforts, yet rarely rigorously studied. METHODS A cross-sectional survey of 1217 households in an epidemic highland site and an endemic lowland site in western Kenya collected information on alternative use in three ways: direct observations, participant self-report, and participant reporting of community-level practices. LLIN misuse was defined as use of an intact net for alternative purposes and repurposing as alternatively using an old or damaged net. Associations between households with observed repurposed nets and universal access and household net use were examined. RESULTS Households describe repurposing nets when they are torn and/or old. Repurposed nets were observed in 8.1% (52/643) highlands households and 33.0% (184/574) lowlands households. Repurposed nets served as chicken coops (33% highlands, 20% lowlands), fences (37% highlands, 25% lowlands), tree covers (22% lowlands), curtains (3% highlands), covering bathrooms (1.5% highlands, 9% lowlands), and washing sponges (13% lowlands). No association was found between repurposing and universal access or household net use. Misuse was rare. Of 379 repurposed nets, 4 (1.06%) were in good condition with no holes. Of 1,758 active nets, 13 (0.74%) were misused. CONCLUSIONS Alternative net use in this study involved repurposing rather than misuse. Repurposing was not detrimental to malaria prevention efforts in these communities. Standardized measurement of alternative net use should be used to better understand the practice and its potential impact on the success of malaria interventions.
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Affiliation(s)
- Ellen M Santos
- Mel and Enid Zuckerman College of Public Health, University of Arizona, 1295 N Martin Ave, Tucson, AZ, 85724, USA.
| | - Jenna E Coalson
- Mel and Enid Zuckerman College of Public Health, University of Arizona, 1295 N Martin Ave, Tucson, AZ, 85724, USA
| | - Stephen Munga
- Centre for Global Health Research, Kenya Medical Research Institute, PO Box 1578, Kisumu, 40100, Nyanza, Kenya
| | - Maurice Agawo
- Centre for Global Health Research, Kenya Medical Research Institute, PO Box 1578, Kisumu, 40100, Nyanza, Kenya
| | - Elizabeth T Jacobs
- Mel and Enid Zuckerman College of Public Health, University of Arizona, 1295 N Martin Ave, Tucson, AZ, 85724, USA
| | - Yann C Klimentidis
- Mel and Enid Zuckerman College of Public Health, University of Arizona, 1295 N Martin Ave, Tucson, AZ, 85724, USA
| | - Mary H Hayden
- National Institute for Human Resilience, University of Colorado, University Office Park Building 1867 Suite 200, Boulder, CO, 80918, USA
| | - Kacey C Ernst
- Mel and Enid Zuckerman College of Public Health, University of Arizona, 1295 N Martin Ave, Tucson, AZ, 85724, USA
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Odufuwa OG, Ross A, Mlacha YP, Juma O, Mmbaga S, Msellemu D, Moore S. Household factors associated with access to insecticide-treated nets and house modification in Bagamoyo and Ulanga districts, Tanzania. Malar J 2020; 19:220. [PMID: 32576180 PMCID: PMC7313165 DOI: 10.1186/s12936-020-03303-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 06/18/2020] [Indexed: 08/29/2023] Open
Abstract
BACKGROUND Insecticide-treated nets (ITNs) and house modifications are proven vector control tools, yet in most regions, full coverage has not been achieved. This study investigates household factors associated with access to ITNs and house modification in Tanzania. METHODS Baseline cross-sectional survey data from previous studies on spatial repellants and indoor residual spray evaluation was analysed from 6757 households in Bagamoyo (60 km north of Dar es Salaam) and 1241 households in Ulanga (a remote rural area in southeast Tanzania), respectively. Regression models were used to estimate the associations between the outcomes: population access to ITNs, access to ITN per sleeping spaces, window screens and closed eaves, and the covariates household size, age, gender, pregnancy, education, house size, house modification (window screens and closed eaves) and wealth. RESULTS Population access to ITNs (households with one ITN per two people that stayed in the house the previous night of the survey) was 69% (n = 4663) and access to ITNs per sleeping spaces (households with enough ITNs to cover all sleeping spaces used the previous night of the survey) was 45% (n = 3010) in Bagamoyo, 3 years after the last mass campaign. These findings are both lower than the least 80% coverage target of the Tanzania National Malaria Strategic Plan (Tanzania NMSP). In Ulanga, population access to ITNs was 92% (n = 1143) and ITNs per sleeping spaces was 88% (n = 1093), 1 year after the last Universal Coverage Campaign (UCC). Increased household size was significantly associated with lower access to ITNs even shortly after UCC. House modification was common in both areas but influenced by wealth. In Bagamoyo, screened windows were more common than closed eaves (65% vs 13%), whereas in Ulanga more houses had closed eaves than window screens (55% vs 12%). CONCLUSION Population access to ITNs was substantially lower than the targets of the Tanzania NMSP after 3 years and lower among larger households after 1 year following ITN campaign. House modification was common in both areas, associated with wealth. Improved access to ITNs and window screens through subsidies and Behaviour Change Communication (BCC) strategies, especially among large and poor households and those headed by people with a low level of education, could maximize the uptake of a combination of these two interventions.
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Affiliation(s)
| | - Amanda Ross
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Yeromin P Mlacha
- Ifakara Health Institute, Bagamoyo, Tanzania.,Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Omary Juma
- Ifakara Health Institute, Bagamoyo, Tanzania
| | | | - Daniel Msellemu
- Ifakara Health Institute, Bagamoyo, Tanzania.,Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Sarah Moore
- Ifakara Health Institute, Bagamoyo, Tanzania.,Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
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28
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Mansiangi P, Umesumbu S, Etewa I, Zandibeni J, Bafwa N, Blaufuss S, Olapeju B, Ntoya F, Sadou A, Irish S, Mukomena E, Kalindula L, Watsenga F, Akogbeto M, Babalola S, Koenker H, Kilian A. Comparing the durability of the long-lasting insecticidal nets DawaPlus ® 2.0 and DuraNet© in northwest Democratic Republic of Congo. Malar J 2020; 19:189. [PMID: 32448213 PMCID: PMC7247235 DOI: 10.1186/s12936-020-03262-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 05/15/2020] [Indexed: 11/30/2022] Open
Abstract
Background Anecdotal reports from DRC suggest that long-lasting insecticidal nets (LLIN) distributed through mass campaigns in DRC may not last the expected average three years. To provide the National Malaria Control Programme with evidence on physical and insecticidal durability of nets distributed during the 2016 mass campaign, two brands of LLIN, DawaPlus® 2.0 and DuraNet©, were monitored in neighbouring and similar health zones in Sud Ubangi and Mongala Provinces. Methods This was a prospective cohort study of representative samples of households from two health zones recruited at baseline, 2 months after the mass campaign. All campaign nets in these households were labelled, and followed up over a period of 31 months. Primary outcome was the “proportion of nets surviving in serviceable condition” based on attrition and integrity measures and the median survival in years. The outcome for insecticidal durability was determined by bio-assay from subsamples of campaign nets. Results A total of 754 campaign nets (109% of target) from 240 households were included in the study. Definite outcomes could be determined for 67% of the cohort nets in Sud Ubangi and 74% in Mongala. After 31 months all-cause attrition was 57% in Sud Ubangi and 76% in Mongala (p = 0.005) and attrition due to wear and tear was 26% in Sud Ubangi and 48% in Mongala (p = 0.0009). Survival in serviceable condition at the last survey was 37% in Sud Ubangi and 17% in Mongala (p = 0.003). Estimated median survival was 1.6 years for the DawaPlus® 2.0 in Mongala (95% CI 1.3–1.9) and 2.2 years for the DuraNet in Sud Ubangi (95% CI 2.0–2.4). Multivariable Cox proportionate hazard models suggest that the difference between sites was mainly attributable to the LLIN brand. Insecticidal effectiveness was optimal for DuraNet©, but significantly dropped after 24 months for DawaPlus® 2.0. Conclusions In the environment of northwest DRC the polyethylene LLIN DuraNet© performed significantly better than the polyester LLIN DawaPlus® 2.0, but both were below a three-year median survival. Improvement of net care behaviours should be able to improve physical durability.
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Affiliation(s)
- Paul Mansiangi
- Ecole de Santé Publique, Université de Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Solange Umesumbu
- National Malaria Control Programme, Kinshasa, Democratic Republic of Congo
| | - Irène Etewa
- Ecole de Santé Publique, Université de Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Jacques Zandibeni
- Ecole de Santé Publique, Université de Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Nissi Bafwa
- Ecole de Santé Publique, Université de Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Sean Blaufuss
- PMI VectorWorks Project, JHU Center for Communication Programs, Baltimore, MD, USA
| | - Bolanle Olapeju
- PMI VectorWorks Project, JHU Center for Communication Programs, Baltimore, MD, USA
| | - Ferdinand Ntoya
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Kinshasa, Democratic Republic of Congo
| | - Aboubacar Sadou
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Kinshasa, Democratic Republic of Congo
| | - Seth Irish
- U.S. President's Malaria Initiative, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Eric Mukomena
- National Malaria Control Programme, Kinshasa, Democratic Republic of Congo
| | - Lydie Kalindula
- National Malaria Control Programme, Kinshasa, Democratic Republic of Congo
| | - Francis Watsenga
- Institut Nationale de Recherche Bio-Medicale, Kinshasa, Democratic Republic of Congo
| | - Martin Akogbeto
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
| | - Stella Babalola
- PMI VectorWorks Project, JHU Center for Communication Programs, Baltimore, MD, USA
| | - Hannah Koenker
- PMI VectorWorks Project, JHU Center for Communication Programs, Baltimore, MD, USA
| | - Albert Kilian
- PMI VectorWorks Project, Tropical Health LLP, Montagut, Spain.
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29
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Haji KA, Khatib BO, Obi E, Dimoso K, Koenker H, Babalola S, Greer G, Serbantez N, Abbas F, Ali A, Blaufuss S, Olapeju B, Kilian A. Monitoring the durability of the long-lasting insecticidal nets Olyset ® and PermaNet ® 2.0 in similar use environments in Zanzibar. Malar J 2020; 19:187. [PMID: 32448313 PMCID: PMC7247136 DOI: 10.1186/s12936-020-03258-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 05/15/2020] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Malaria transmission in Zanzibar has dramatically reduced in recent years but vector control interventions such as long-lasting insecticidal nets (LLIN) must continue to reach malaria elimination. To achieve this, the Zanzibar Malaria Elimination Programme needs actionable evidence of the durability of the LLIN brands distributed. This study compared physical and insecticidal durability of two LLIN brands: Olyset® and PermaNet© 2.0 in two similar districts on the islands of Unguja and Pemba. METHODS This was a prospective cohort study of representative samples of households from two districts, recruited at baseline 4 months after the mass campaign. All campaign nets in these households were labelled and followed up over a period of 33 months. Primary outcome was the "proportion of nets surviving in serviceable condition" based on attrition and integrity measures and the median survival in years. The outcome for insecticidal durability was determined by bio-assay from sub-samples of campaign nets. RESULTS A total of 834 campaign nets (121% of target) from 299 households were included in the study. Definite outcomes could be determined for 86% of the cohort nets in Unguja (PermaNet® 2.0) and 89% in Pemba (Olyset®). After 33 months, physical survival in serviceable condition was 55% in Unguja and 51% in Pemba. Estimated median survival was lower in Pemba at all time points with 2.3-2.7 years compared to 3.1-3.3 yeas in Unguja. Multivariable Cox proportionate hazard models confirmed the difference between brands (p < 0.0001) and identified household net-care attitude (p = 0.007) and folding of hanging nets during the day (p < 0.0001) as significant determinants, in addition to exclusive use of nets by adults (p = 0.03) and use only over a finished bedframe (p = 0.01). Optimal insecticidal effectiveness was 80% or higher for both brands at all time points when both cone bio-assays and tunnel tests were applied. CONCLUSIONS After 3 years of follow-up, Olyset® LLIN showed significantly lower physical survival compared to PermaNet® 2.0 LLIN even after adjusting for other variables of net-use environment and net handling. This suggests that the differences were driven by the textile characteristics of the LLIN brands.
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Affiliation(s)
- Khamis Ameir Haji
- Zanzibar Malaria Elimination Programme, Stone Town, Zanzibar, Tanzania
| | | | - Emmanuel Obi
- PMI VectorWorks Project, Tropical Health LLP, Abuja, Nigeria
| | - Kanuth Dimoso
- PMI VectorWorks Project, JHU Center for Communication Programs, Dar es Salaam, Tanzania
| | - Hannah Koenker
- PMI VectorWorks Project, JHU Center for Communication Programs, Baltimore, MD, USA
| | - Stella Babalola
- PMI VectorWorks Project, JHU Center for Communication Programs, Baltimore, MD, USA
| | - George Greer
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Dar es Salaam, Tanzania
| | - Naomi Serbantez
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Dar es Salaam, Tanzania
| | - Faiza Abbas
- Zanzibar Malaria Elimination Programme, Stone Town, Zanzibar, Tanzania
| | - Abdullah Ali
- Zanzibar Malaria Elimination Programme, Stone Town, Zanzibar, Tanzania
| | - Sean Blaufuss
- PMI VectorWorks Project, JHU Center for Communication Programs, Baltimore, MD, USA
| | - Bolanle Olapeju
- PMI VectorWorks Project, JHU Center for Communication Programs, Baltimore, MD, USA
| | - Albert Kilian
- PMI VectorWorks Project, Tropical Health LLP, Montagut, Spain.
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30
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Ghimire P, Rijal KR, Adhikari N, Thakur GD, Marasini B, Thapa Shrestha U, Banjara MR, Pant SK, Adhikari B, Dumre SP, Singh N, Pigeon O, Chareonviriyaphap T, Chavez I, Ortega L, Hii J. The durability of long-lasting insecticidal nets distributed to the households between 2009 and 2013 in Nepal. Trop Med Health 2020; 48:36. [PMID: 32476984 PMCID: PMC7236445 DOI: 10.1186/s41182-020-00223-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 05/05/2020] [Indexed: 11/10/2022] Open
Abstract
Background Understanding and improving the durability of long-lasting insecticidal nets (LLINs) in the field are critical for planning future implementation strategies including behavioral change for care and maintenance. LLIN distribution at high coverage is considered to be one of the adjunctive transmission reduction strategies in Nepal's Malaria Strategic Plan 2014-2025. The main objective of this study was to assess the durability through assessment of community usage, physical integrity, residual bio-efficacy, and chemical retention in LLINs: Interceptor®, Yorkool®, and PermaNet ®2.0 which were used in Nepal during 2009 through 2013. Methods Assessments were conducted on random samples (n = 440) of LLINs from the eleven districts representing four ecological zones: Terai plain region (Kailali and Kanchanpur districts), outer Terai fluvial ecosystem (Surkhet, Dang, and Rupandhei districts), inner Terai forest ecosystem (Mahhothari, Dhanusa, and Illam districts), and Hills and river valley (Kavrepalanchock and Sindhupalchok districts). For each LLIN, fabric integrity in terms of proportionate hole index (pHI) and residual bio-efficacy were assessed. However, for chemical retention, a representative sample of 44 nets (15 Yorkool®, 10 Permanet®2.0, and 19 Interceptor®) was evaluated. Data were analyzed using descriptive statistics stratified by LLINs brand, districts, and duration of exposure. Results On average, duration of use of LLINs was shortest for the Yorkool® samples, followed by PermaNet® 2.0 and Interceptor® with median ages of 8.9 (IQR = 0.4), 23.8 (IQR = 3.2), and 50.1 (IQR = 3.2) months, respectively. Over 80% of field distributed Yorkool® and PermaNet® 2.0 nets were in good condition (pHI< 25) compared to Interceptor® (66%). Bio-efficacy analysis showed that average mortality rates of Interceptor and Yorkool were below World Health Organization (WHO) optimal effectiveness of ≥ 80% compared to 2-year-old PermaNet 2.0 which attained 80%. Chemical retention analysis was consistent with bio-efficacy results. Conclusion This study shows that distribution of LLINs is effective for malaria control; however, serviceable life of LLINs should be considered in terms of waning residual bio-efficacy that warrants replacement. As an adjunctive malaria control tool, National Malaria Control Program of Nepal can benefit by renewing the distribution of LLINs in an appropriate time frame in addition to utilizing durable and effective LLINs.
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Affiliation(s)
- Prakash Ghimire
- 1Central Department of Microbiology, Tribhuvan University, Kathmandu, Nepal.,World Health Organization Country Office for Nepal, Pulchowk, Lalitpur, Nepal
| | - Komal Raj Rijal
- 1Central Department of Microbiology, Tribhuvan University, Kathmandu, Nepal
| | - Nabaraj Adhikari
- 1Central Department of Microbiology, Tribhuvan University, Kathmandu, Nepal
| | - Garib Das Thakur
- 3Epidemiology and Disease Control Division, Department of Health Services, Ministry of Health and Population, Kathmandu, Nepal
| | - Baburam Marasini
- 3Epidemiology and Disease Control Division, Department of Health Services, Ministry of Health and Population, Kathmandu, Nepal
| | | | - Megha Raj Banjara
- 1Central Department of Microbiology, Tribhuvan University, Kathmandu, Nepal
| | - Shishir Kumar Pant
- 4VectorBorne Disease Research and Training Center, Ministry of Health and Population, Hetauda, Nepal
| | - Bipin Adhikari
- 5Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Shyam Prakash Dumre
- 6Department of Immunogenetics, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Nihal Singh
- World Health Organization Country Office for Nepal, Pulchowk, Lalitpur, Nepal
| | - Olivier Pigeon
- 7Agriculture and Natural Environment Department, Plant Protection Products and Biocides Physico-chemistry and Residues Unit, Walloon Agricultural Research Centre (CRA-W), Carson Building, Rue du Bordia, 11, B-5030 Gembloux, Belgium
| | | | - Irwin Chavez
- 9Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Bangkok, 10400 Thailand
| | - Leonard Ortega
- 10South-East Asia Regional Office, World Health Organization, New Delhi, India.,11Global Malaria Programme World Health Organization, 20 Avenue Appia, 1211 Geneva 27, Switzerland
| | - Jeffrey Hii
- 12Malaria Consortium, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Bangkok, 10400 Thailand.,13College of Public Health, Medical & Veterinary Sciences, James Cook University, Townville, QLD 4811 Australia
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31
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Obi E, Okoh F, Blaufuss S, Olapeju B, Akilah J, Okoko OO, Okechukwu A, Maire M, Popoola K, Yahaya MA, Uneke CJ, Awolola S, Pigeon O, Babalola S, Koenker H, Kilian A. Monitoring the physical and insecticidal durability of the long-lasting insecticidal net DawaPlus ® 2.0 in three States in Nigeria. Malar J 2020; 19:124. [PMID: 32228592 PMCID: PMC7106771 DOI: 10.1186/s12936-020-03194-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 03/20/2020] [Indexed: 11/23/2022] Open
Abstract
Background Following guidance from the US President’s Malaria Initiative, durability monitoring of DawaPlus® 2.0 brand of long-lasting insecticidal net (LLIN) distributed during the 2015/16 mass campaign was set up in three ecologically different states: Zamfara, Ebonyi and Oyo. Methods This was a prospective cohort study of representative samples of households from each location, recruited at baseline, 1 to 6 months after the mass campaign. All campaign nets in the households were labelled and followed up over a period of 36 months in Zamfara and Ebonyi and 24 months in Oyo. Primary outcome was the “proportion of nets surviving in serviceable condition” based on attrition and integrity measures and the median survival in years. The outcome for insecticidal durability was determined by bio-assay from sub-samples of campaign nets. Results A total of 439 households (98% of target) and 1096 campaign nets (106%) were included in the study. Definite outcomes could be determined for 92% of the cohort nets in Zamfara, 88% in Ebonyi and 75% in Oyo. All-cause attrition was highest in Oyo with 47% no longer present after 24 months, 53% in Ebonyi and 28% in Zamfara after 36 months. Overall only 1% of all campaign nets were used for other purposes. Estimated survival in serviceable condition of the campaign nets was 80% in Zamfara, 55% in Ebonyi (36 months follow-up) and 75% in Oyo (24 months follow-up) corresponding to median survival of 5.3, 3.3, 3.2 years, respectively. Factors associated with better survival were exposure to social messaging combined with a positive net-care attitude and only adult users. Failing to fold the net when hanging and having children under 5 years of age in the household negatively impacted net survival. Insecticidal effectiveness testing at final survey showed knock-down rates of 50–69%, but 24-h mortality above 95% resulting in 100% optimal performance in Ebonyi and Oyo and 97% in Zamfara. Conclusions Results confirm the strong influence of net-use environment and behavioural factors in the physical survival of the same LLIN brand, which can increase the time until 50% of nets are no longer serviceable by up to 2 years.
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Affiliation(s)
- Emmanuel Obi
- PMI VectorWorks Project, Tropical Health LLP, Abuja, Nigeria
| | - Festus Okoh
- National Malaria Elimination Programme, Abuja, Nigeria
| | - Sean Blaufuss
- PMI VectorWorks Project, JHU Center for Communication Programs, Baltimore, MD, USA
| | - Bolanle Olapeju
- PMI VectorWorks Project, JHU Center for Communication Programs, Baltimore, MD, USA
| | - Joel Akilah
- National Malaria Elimination Programme, Abuja, Nigeria
| | | | - Abidemi Okechukwu
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Abuja, Nigeria
| | - Mark Maire
- U.S. President's Malaria Initiative, Centers for Disease Control and Prevention, Abuja, Nigeria
| | | | | | - Chigozie Jesse Uneke
- Dept. of Medical Microbiology/Parasitology, Ebonyi State University, Abakaliki, Nigeria
| | | | | | - Stella Babalola
- PMI VectorWorks Project, JHU Center for Communication Programs, Baltimore, MD, USA
| | - Hannah Koenker
- PMI VectorWorks Project, JHU Center for Communication Programs, Baltimore, MD, USA
| | - Albert Kilian
- PMI VectorWorks Project, Tropical Health LLP, Montagut, Spain.
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Scates SS, Finn TP, Wisniewski J, Dadi D, Mandike R, Khamis M, Greer G, Serbantez N, Segbaya S, Owusu P, Mihigo J, Gerberg L, Acosta A, Koenker H, Yukich J. Costs of insecticide-treated bed net distribution systems in sub-Saharan Africa. Malar J 2020; 19:105. [PMID: 32131834 PMCID: PMC7055111 DOI: 10.1186/s12936-020-03164-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 02/13/2020] [Indexed: 12/01/2022] Open
Abstract
Background Insecticide-treated nets (ITNs) are one of the most cost-effective measures for preventing malaria. The World Health Organization recommends both large-scale mass distribution campaigns and continuous distributions (CD) as part of a multifaceted strategy to achieve and sustain universal access to ITNs. A combination of these strategies has been effective for scaling up ITN access. For policy makers to make informed decisions on how to efficiently implement CD or combined strategies, information on the costs and cost-effectiveness of these delivery systems is necessary, but relatively few published studies of the cost continuous distribution systems exist. Methods To address the gap in continuous distribution cost data, four types of delivery systems—CD through antenatal care services (ANC) and the expanded programme on immunization (EPI) (Ghana, Mali, and mainland Tanzania), CD through schools (Ghana and mainland Tanzania), and a combined community/health facility-based distribution (Zanzibar, Tanzania), as well as mass distributions (Mali)—were costed. Data on costs were collected retrospectively from financial and operational records, stakeholder interviews, and resource use surveys. Results Overall, from a full provider perspective, mass distributions and continuous systems delivered ITNs at overlapping economic costs per net distributed (mass distributions: 4.37–4.61 USD, CD channels: 3.56–9.90 USD), with two of the school-based systems and the mass distributions at the lower end of this range. From the perspective of international donors, the costs of the CD systems were, for the most part, less costly than the mass distributions (mass distributions: 4.34–4.55 USD, Ghana and Tanzania 2017 school-based: 3.30–3.69 USD, health facility-based: 3.90–4.55 USD, combined community/health facility 4.55 USD). The 2015 school-based distribution (7.30 USD) and 2016 health facility-based distribution (6.52 USD) programmes in Tanzania were an exception. Mass distributions were more heavily financed by donors, while CD relied more extensively on domestic resource contributions. Conclusions These results suggest that CD strategies can continue to deliver nets at a comparable cost to mass distributions, especially from the perspective of the donor.
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Affiliation(s)
- Sara S Scates
- PMI VectorWorks Project, Department of Tropical Medicine and the Center for Applied Malaria Research and Evaluation, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA.
| | - Timothy P Finn
- PMI VectorWorks Project, Department of Tropical Medicine and the Center for Applied Malaria Research and Evaluation, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Janna Wisniewski
- PMI VectorWorks Project, Department of Tropical Medicine and the Center for Applied Malaria Research and Evaluation, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - David Dadi
- PMI VectorWorks Project, Johns Hopkins University Center for Communication Programs, Baltimore, MD, USA
| | - Renata Mandike
- Tanzania National Malaria Control Programme, Dodoma, Tanzania
| | - Mwinyi Khamis
- Zanzibar Malaria Elimination Programme, Zanzibar, Tanzania
| | - George Greer
- U.S. President's Malaria Initiative, US Agency for International Development, Dar es Salaam, Tanzania
| | - Naomi Serbantez
- U.S. President's Malaria Initiative, US Agency for International Development, Dar es Salaam, Tanzania
| | - Sylvester Segbaya
- PMI VectorWorks Project, Johns Hopkins University Center for Communication Programs, Baltimore, MD, USA
| | - Prince Owusu
- PMI VectorWorks Project, Johns Hopkins University Center for Communication Programs, Baltimore, MD, USA
| | - Jules Mihigo
- U.S. President's Malaria Initiative, US Agency for International Development, Bamako, Mali
| | - Lilia Gerberg
- U.S President's Malaria Initiative, U.S. Agency for International Development, Washington, D.C., USA
| | - Angela Acosta
- PMI VectorWorks Project, Johns Hopkins University Center for Communication Programs, Baltimore, MD, USA
| | - Hannah Koenker
- PMI VectorWorks Project, Johns Hopkins University Center for Communication Programs, Baltimore, MD, USA
| | - Joshua Yukich
- PMI VectorWorks Project, Department of Tropical Medicine and the Center for Applied Malaria Research and Evaluation, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
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Ahogni IB, Salako AS, Akinro B, Sovi A, Gnanguenon V, Azondekon R, Dagnon JF, Akogbeto P, Tokponon F, Akogbeto MC. Physical integrity and survivorship of long-lasting insecticidal nets distributed to households of the same socio-cultural community in Benin, West Africa. Malar J 2020; 19:58. [PMID: 32019586 PMCID: PMC7001382 DOI: 10.1186/s12936-020-3138-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 01/24/2020] [Indexed: 11/10/2022] Open
Abstract
Background Long-lasting insecticidal nets (LLINs) are designed to survive and sustain their physical barrier for 3 years in household conditions. However, studies have shown that most of these nets are usually torn or no longer present in the households in less than 3 years. This study was initiated in Benin to compare the survivorship and physical integrity of seven types of LLINs in a same socio-geographic area. Methods In August 2017, 1890 households were selected in 9 villages in the municipality of Zagnanado in central Benin. Each one of the selected households received one of the seven LLIN products: Aspirational®, DawaPlus® 2.0, OlysetNet®, PermaNet® 2.0, PermaNet® 3.0, Royal Sentry® and Yorkool®. Overall, 270 LLINs of each type were freely distributed in Zagnanado, at a rate of 30 LLINs per type per village. These bed nets have been monitored and evaluated every 6 months to identify the most resilient and preferred LLINs in the community. Net survivorship was assessed using the rate of net loss and physical condition. Results The survivorship of all types of LLIN was estimated at 92% (95% CI 90.33–92.96) after 6 months and 70% (95% CI 67.25–71.81) after a year of use. At 12 months, all bed nets monitored were below the NetCalc model threshold of 92.8% for an LLIN with a lifespan of 3 years. Only 1.73% of all types of LLIN had a visible loss of integrity after 6 months with a median proportionate hole index (PHI) estimated at zero. The percentage significantly increased after 12 months with 10.41% of damaged nets (all types of LLINs). The median PHI for each brand of net was 23, 196, 141, 23, 23, 121 and 72, respectively for Aspirational®, DawaPlus® 2.0, OlysetNet®, PermaNet® 2.0, PermaNet® 3.0, Royal Sentry® and Yorkool®. A significant difference was noted between the PHI at 6 and 12 months (p < 0.0001). After 12 months, the DawaPlus®2.0, OlysetNet® and Royal Sentry® suffered significantly more damage compared to the others (p < 0.001). Conclusion The results of this study showed that after a year of use, the survivorship of the 7 LLIN products in households was lower than expected. However, all the LLIN products successfully met WHO standards for physical integrity after 12 months of use. The monitoring continues. The next steps will help to identify the most sustainable LLINs.
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Affiliation(s)
- Idelphonse B Ahogni
- Centre de Recherche Entomologique de Cotonou (CREC), Ministry of Health, Cotonou, Benin. .,Faculté des Sciences et Techniques, University of Abomey-Calavi, Abomey-Calavi, Benin.
| | - Albert S Salako
- Centre de Recherche Entomologique de Cotonou (CREC), Ministry of Health, Cotonou, Benin.,Faculté des Sciences et Techniques, University of Abomey-Calavi, Abomey-Calavi, Benin
| | - Bruno Akinro
- Centre de Recherche Entomologique de Cotonou (CREC), Ministry of Health, Cotonou, Benin.,International Chair of Physics, Mathematics and Application, ICPMA, Dangbo, Benin
| | - Arthur Sovi
- Faculté d'Agronomie, Université de Parakou (UP), Parakou, Benin
| | | | - Roseric Azondekon
- Centre de Recherche Entomologique de Cotonou (CREC), Ministry of Health, Cotonou, Benin.,University of Wisconsin Milwaukee, Milwaukee, USA
| | - Jean F Dagnon
- President's Malaria Initiative, US Agency for International Development, Cotonou, Benin
| | - Pamela Akogbeto
- Centre de Recherche Entomologique de Cotonou (CREC), Ministry of Health, Cotonou, Benin
| | | | - Martin C Akogbeto
- Centre de Recherche Entomologique de Cotonou (CREC), Ministry of Health, Cotonou, Benin
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Henderson SJ, Belemvire A, Nelson R, Linn A, Moriarty LF, Brofsky E, Diaw M, Gittelman D. Advancing Malaria Prevention and Control in Africa Through the Peace Corps-US President’s Malaria Initiative Partnership. Glob Adv Health Med 2020; 9:2164956120976107. [PMID: 35174005 PMCID: PMC8842444 DOI: 10.1177/2164956120976107] [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: 07/27/2020] [Revised: 10/24/2020] [Accepted: 11/04/2020] [Indexed: 11/26/2022] Open
Abstract
Background Peace Corps is a US government volunteer service agency which provides trained Volunteers to assist host countries in addressing critical development challenges at the community level. The US President’s Malaria Initiative provides technical expertise and financial resources to reduce malaria morbidity and mortality in focus countries in sub-Saharan Africa. Objective We aim to describe the nature of the collaboration between Peace Corps and President’s Malaria Initiative (PMI) and highlight examples of the partnership in select countries. Methods We conducted an analysis of retrospective data obtained from Peace Corps and PMI for the years 2014–2019. Results Volunteers were able to learn about and work on malaria prevention and control with PMI in three key ways: a malaria-specific training program for staff and Volunteers; malaria-focused small grants; and extension of Volunteer assignments for a third year to support malaria projects. Successful Peace Corps projects supported by PMI, at the community level, were highlighted, with a focus on Rwanda, Benin, Zambia, Madagascar, and Senegal. In Fiscal Year 2019, 1408 Volunteers contributed to malaria prevention activities in 18 Peace Corps programs across Africa, of which 15 were PMI focus countries. While the majority of documented work by Volunteers has involved social and behavior change, there were many other ways to partner with PMI staff. Conclusion Each of the proven interventions that PMI supports for malaria prevention and control may have a role for Volunteer involvement. Combined with the technical expertise and the relationships that PMI staff have with national-level counterparts in PMI focus countries, the continued collaboration between Peace Corps and PMI can accelerate the fight against malaria.
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Affiliation(s)
- Susan J Henderson
- US President’s Malaria Initiative, Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Allison Belemvire
- US President’s Malaria Initiative, US Agency for International Development, Washington, District of Columbia
| | - Roman Nelson
- US Peace Corps, Washington, District of Columbia
| | - Anne Linn
- US President’s Malaria Initiative, US Agency for International Development, Washington, District of Columbia
| | - Leah F Moriarty
- US President’s Malaria Initiative, Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Emma Brofsky
- US President’s Malaria Initiative, US Agency for International Development, Washington, District of Columbia
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Yadav K, Dhiman S, Acharya BN, Ghorpade RR, Sukumaran D. Pyriproxyfen treated surface exposure exhibits reproductive disruption in dengue vector Aedes aegypti. PLoS Negl Trop Dis 2019; 13:e0007842. [PMID: 31738760 PMCID: PMC6886876 DOI: 10.1371/journal.pntd.0007842] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 12/02/2019] [Accepted: 10/13/2019] [Indexed: 11/21/2022] Open
Abstract
Background Reduced susceptibility of mosquito vectors to currently used insecticides hampers control interventions. Recently pyriproxyfen, an insect growth regulator has been demonstrated to effectively reduce the reproductive potential in vector mosquitoes. Methods Pyriproxyfen (PPF), in different concentrations (0.75%, 0.075%, 0.0075%, and 0.00075%) was applied on papers and Indian wild type Aedes aegypti female mosquitoes (N ≥ 20 for each treatment) were exposed onto it as per WHO guidelines, to study the reproductive disruption. PPF concentration on treated papers was quantitatively cross-determined using HPLC method. Reduction in fecundity, fertility and adult emergence in exposed female Ae. aegypti was determined. Abnormal development in ovary and eggs of exposed females was studied microscopically after different time intervals. Results Eggs laid, eggs hatched, pupae formed and adults emerged per female exposed in both before blood meal and after blood meal groups declined significantly from lowest to highest concentration of PPF (F ≥ 5.2; p < 0.02). Adult emergence inhibition in females exposed to PPF before and after blood meal groups ranged from 58.8% [OR = 0.18 (95% CI = 0.09–0.36)] to 79.2% [OR = 0.04 (95% CI = 0.02–0.10)] and 64.4% [OR = 0.12 (95% CI = 0.05–0.28)] to 77.1% [OR = 0.05 (95% CI = 0.02–0.14)] respectively in different concentrations. The probit model used suggested that FI50 (50% fertility inhibition) and EI50 (50% emergence inhibition) were 0.002% (p = 0.82) and 0.0001% (p = 0.99) for females exposed before blood meal, while 0.01% (p = 0.63) and <0.0001% (p = 0.98) for the females exposed after blood meal, respectively. The eggs laid by the females exposed to PPF-treated surface showed altered body organization, desegmentation and disoriented abdominal and cervical regions in the developing embryo. Quantification of PPF on impregnated papers showed that it was uniformly distributed throughout the matrix. Conclusions The present study has shown that tarsal contact to PPF-treated surface for a small time drastically influenced the fecundity, fertility and adult emergence in Indian wild Ae. aegypti mosquitoes. Results suggest that a certain minimum concentration of PPF through contact exposure can reduce the abundance of vector mosquitoes to a considerable level. The formulations based on combination of PPF and other compatible insecticides may be an impactful approach where susceptible mosquitoes are killed by the insecticide component while resistant mosquitoes are sterilised by PPF. Development of resistance against insecticides has challenged mosquito control programmes globally and prompted the research of alternative options that can complement insecticides. An insect growth regulator, pyriproxyfen (PPF) usage against mosquitoes can effectively reduce the vector population. PPF mainly inhibits the metamorphosis of mosquito larvae into pupae and prevent the adult emergence, therefore it is generally applied in mosquito breeding habitats. PPF has been shown to exhibit delayed residual effect that may impair the reproductive capacity by affecting the survival, fecundity and fertility of adult mosquito exposed through tarsal contact. Presently, the effectiveness of different concentrations of PPF intended to be delivered through contact have been evaluated against dengue vector Ae. aegypti. Results suggested that very low PPF concentration treated surfaces drastically reduce the fecundity, fertility and adult emergence in mosquitoes. Study suggests that control interventions based on PPF-treated surfaces could provide an additional route to target mosquito vector control by overall population density reduction.
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Affiliation(s)
- Kavita Yadav
- Vector Management Division, Defence Research and Development Establishment, Gwalior, Madhya Pradesh, India
- * E-mail:
| | - Sunil Dhiman
- Vector Management Division, Defence Research and Development Establishment, Gwalior, Madhya Pradesh, India
| | - BN Acharya
- Synthetic Chemistry Division, Defence Research and Development Establishment, Gwalior, Madhya Pradesh, India
| | - Rama Rao Ghorpade
- Synthetic Chemistry Division, Defence Research and Development Establishment, Gwalior, Madhya Pradesh, India
| | - Devanathan Sukumaran
- Vector Management Division, Defence Research and Development Establishment, Gwalior, Madhya Pradesh, India
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Andronescu LR, Buchwald AG, Coalson JE, Cohee L, Bauleni A, Walldorf JA, Kandangwe C, Mzilahowa T, Taylor TE, Mathanga DP, Laufer MK. Net age, but not integrity, may be associated with decreased protection against Plasmodium falciparum infection in southern Malawi. Malar J 2019; 18:329. [PMID: 31551076 PMCID: PMC6760057 DOI: 10.1186/s12936-019-2930-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 08/22/2019] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Distribution campaigns for insecticide-treated nets (ITN) have increased the use of ITNs in Malawi, but malaria prevalence remains high even among those using the nets. Previous studies have addressed ITN ownership, insecticide resistance, and frequency of ITN use as possible contributing factors to the high prevalence of malaria infection despite high ITN coverage, but have rarely considered whether the condition of the ITN, or how many people use it, impacts efficacy. This study assessed how ITN integrity, ITN age, and the number of persons sharing a net might mitigate or reduce protective efficacy among self-identified ITN users in Malawi. METHODS From 2012 to 2014, six cross-sectional surveys were conducted in both the rainy and dry seasons in southern Malawi. Data were collected on ITN use, integrity (number and size of holes), and age. Blood samples for detecting Plasmodium falciparum infection were obtained from reported ITN users over 6 months of age. Generalized linear mixed models were used to account for clustering at the household and community level. The final model controlled for gender, household eaves, and community-level infection prevalence during the rainy season. RESULTS There were 9646 ITN users with blood samples across six surveys, 15% of whom tested positive for P. falciparum infection. Among children under 5 years old, there was a 50% increased odds of P. falciparum infection among those sleeping under an ITN older than two years, compared to those using an ITN less than 2 years old (OR = 1.50; 95% CI 1.07-2.08). ITN integrity and number of individuals sharing an ITN were not associated with P. falciparum infection. CONCLUSIONS Older ITNs were associated with higher rates of P. falciparum in young children, which may indicate that insecticide concentrations play a larger role in infection prevention than the physical barrier of an ITN. ITN use was self-reported and the integrity measures lacked the precision of newer methods, suggesting a need for objective measures of ITN use and more precise assessment of ITN integrity.
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Affiliation(s)
- Liana R. Andronescu
- 0000 0001 2175 4264grid.411024.2Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685 W, Baltimore Street, Baltimore, MD 21201 USA
| | - Andrea G. Buchwald
- 0000 0001 2175 4264grid.411024.2Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685 W, Baltimore Street, Baltimore, MD 21201 USA ,0000 0001 0703 675Xgrid.430503.1Present Address: University of Colorado School of Public Health, University of Colorado, 13001 E, 17th Place, Mail Stop B119, Aurora, CO 80045 USA
| | - Jenna E. Coalson
- 0000 0001 2168 186Xgrid.134563.6Mel and Enid Zuckerman College of Public Health, University of Arizona, 1295N Martin Ave, Tucson, AZ 85724 USA
| | - Lauren Cohee
- 0000 0001 2175 4264grid.411024.2Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685 W, Baltimore Street, Baltimore, MD 21201 USA
| | - Andy Bauleni
- 0000 0001 2113 2211grid.10595.38Malaria Alert Centre, University of Malawi College of Medicine, Blantyre, Malawi
| | - Jenny A. Walldorf
- 0000 0001 2175 4264grid.411024.2Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685 W, Baltimore Street, Baltimore, MD 21201 USA ,0000 0001 2163 0069grid.416738.fPresent Address: Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA USA
| | - Chifundo Kandangwe
- 0000 0001 2113 2211grid.10595.38Malaria Alert Centre, University of Malawi College of Medicine, Blantyre, Malawi
| | - Themba Mzilahowa
- 0000 0001 2113 2211grid.10595.38Malaria Alert Centre, University of Malawi College of Medicine, Blantyre, Malawi
| | - Terrie E. Taylor
- 0000 0001 2150 1785grid.17088.36Department of Osteopathic Medical Specialties, Michigan State University, 909 Fee Road, East Lansing, MI 48824 USA
| | - Don P. Mathanga
- 0000 0001 2113 2211grid.10595.38Malaria Alert Centre, University of Malawi College of Medicine, Blantyre, Malawi
| | - Miriam K. Laufer
- 0000 0001 2175 4264grid.411024.2Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685 W, Baltimore Street, Baltimore, MD 21201 USA
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Santos EM, Coalson JE, Jacobs ET, Klimentidis YC, Munga S, Agawo M, Anderson E, Stroupe N, Ernst KC. Bed net care practices and associated factors in western Kenya. Malar J 2019; 18:274. [PMID: 31412865 PMCID: PMC6694604 DOI: 10.1186/s12936-019-2908-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 08/08/2019] [Indexed: 11/22/2022] Open
Abstract
Background Insecticide-treated nets (ITNs) and long-lasting insecticidal nets (LLINs) are effective for malaria prevention and are designed to provide nearly 5 years of mosquito protection. However, many ITNs and LLINs become damaged and ineffective for mosquito bite prevention within 1 to 2 years in field conditions. Non-adherence to recommended bed net care and repair practices may partially explain this shortened net longevity. Methods Using data from a cross-sectional study, a net care adherence score was developed and adherence to net care practices described from two regions of western Kenya. Relationships between attitudes and environmental factors that influence net longevity were measured with adherence to bed net care practices. Results While overall care practices are highly adherent particularly in the highlands, practices related to daily storage, washing frequency, and drying location need improvement in the lowlands. Seventy-seven percent of nets in the lowlands were washed < 3 months prior to the survey compared to 23% of nets in the highlands. More nets were dried in the sun in the lowlands (32% of nets) compared to the highlands (4% of nets). Different elements of care are influenced by various malaria attitudes and environmental factors, highlighting the complexity of factors associated with net care. For example, households that learned about net care from community events, that share a sleeping structure with animals, and that have nets used by adult males tend to adhere to washing frequency recommendations. Conclusions In western Kenya, many nets are cared for in accordance to recommended practices, particularly in the highlands sites. In the lowlands, demonstrating methods at community events to tie nets up during the day coupled with messaging to emphasize infrequent washing and drying nets in the shade may be an appropriate intervention. As illustrated by differences between the highlands and lowlands sites in the present study, should interventions to improve adherence to bed net care practices be necessary, they should be context-specific. Electronic supplementary material The online version of this article (10.1186/s12936-019-2908-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ellen M Santos
- Mel and Enid Zuckerman College of Public Health, University of Arizona, 1295N Martin Ave, Tucson, AZ, 85724, USA.
| | - Jenna E Coalson
- Mel and Enid Zuckerman College of Public Health, University of Arizona, 1295N Martin Ave, Tucson, AZ, 85724, USA
| | - Elizabeth T Jacobs
- Mel and Enid Zuckerman College of Public Health, University of Arizona, 1295N Martin Ave, Tucson, AZ, 85724, USA
| | - Yann C Klimentidis
- Mel and Enid Zuckerman College of Public Health, University of Arizona, 1295N Martin Ave, Tucson, AZ, 85724, USA
| | - Stephen Munga
- Centre for Global Health Research, Kenya Medical Research Institute, PO Box 1578, Kisumu, Nyanza, 40100, Kenya
| | - Maurice Agawo
- Centre for Global Health Research, Kenya Medical Research Institute, PO Box 1578, Kisumu, Nyanza, 40100, Kenya
| | - Elizabeth Anderson
- Mel and Enid Zuckerman College of Public Health, University of Arizona, 1295N Martin Ave, Tucson, AZ, 85724, USA
| | - Nancy Stroupe
- Mel and Enid Zuckerman College of Public Health, University of Arizona, 1295N Martin Ave, Tucson, AZ, 85724, USA
| | - Kacey C Ernst
- Mel and Enid Zuckerman College of Public Health, University of Arizona, 1295N Martin Ave, Tucson, AZ, 85724, USA
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LLIN Evaluation in Uganda Project (LLINEUP): factors associated with childhood parasitaemia and anaemia 3 years after a national long-lasting insecticidal net distribution campaign: a cross-sectional survey. Malar J 2019; 18:207. [PMID: 31234882 PMCID: PMC6591906 DOI: 10.1186/s12936-019-2838-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Accepted: 06/14/2019] [Indexed: 12/31/2022] Open
Abstract
Background Recent reductions in malaria burden have been attributed largely to long-lasting insecticidal nets (LLINs). In March–June 2017, approximately 3 years after a national LLIN distribution campaign, a cross-sectional community survey was conducted to investigate factors associated with malaria parasitaemia and anaemia, in advance of Uganda’s 2017–2018 LLIN campaign. Methods Households from 104 clusters in 48 districts were randomly selected using two-staged cluster sampling; 50 households were enrolled per cluster. Eligible children aged 2–10 years had blood obtained for a thick blood smear and those aged 2–4 years had haemoglobin measured. Associations between outcomes and variables of interest were assessed using log-binomial regression with generalized estimating equations to adjust for household clustering. Results In total, 5196 households, 8834 children with blood smear results, and 3753 with haemoglobin results were included. Only 16% of children lived in households with adequate LLIN coverage. Overall, parasite prevalence was 26.0%, ranging from 8.0% in the South West to 53.1% in East Central. Limiting data to children 2–4 years of age, parasite prevalence was 21.4%, up from 16.9% in 2014–2015 following the national LLIN campaign. In a multivariate analysis, factors associated with parasitaemia included region (East-Central vs South-Western; adjusted prevalence ratio [aPR] 6.45, 95% CI 5.55–7.50; p < 0.001), older age (8–10 vs 2–3 years; aPR 1.57, 95% CI 1.43–1.72; p < 0.001), living in a poorer household (poorest vs least poor tercile; aPR 2.32, 95% CI 2.05–2.63; p < 0.001), one constructed of traditional materials (aPR 1.13, 95% CI 1.03–1.24; p = 0.008), or without adequate LLIN coverage (aPR 1.30, 95% CI 1.14–1.48; p < 0.001). Overall, the prevalence of anaemia (haemoglobin < 10 g/dL) was 15.1% and varied geographically. In a multivariate analysis, factors associated with anaemia included region, younger age, living in a traditional house, and parasitaemia, which was the strongest predictor (aPR 2.50, 95% CI 2.12–2.95; p < 0.001). Conclusions Three years after a national LLIN campaign, LLIN coverage was low and parasite prevalence had increased. Parasite prevalence varied widely across Uganda; older children, those living in poorer households, and those with inadequate LLIN coverage, were at highest risk of parasitaemia. LLINs may need to be distributed more frequently through mass campaigns or continuously through sustainable mechanisms. Targeting interventions to geographic areas and populations at highest risk should also be considered.
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Massue DJ, Lorenz LM, Moore JD, Ntabaliba WS, Ackerman S, Mboma ZM, Kisinza WN, Mbuba E, Mmbaga S, Bradley J, Overgaard HJ, Moore SJ. Comparing the new Ifakara Ambient Chamber Test with WHO cone and tunnel tests for bioefficacy and non-inferiority testing of insecticide-treated nets. Malar J 2019; 18:153. [PMID: 31039788 PMCID: PMC6492396 DOI: 10.1186/s12936-019-2741-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 03/21/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Insecticide-treated net (ITN) durability, measured through physical integrity and bioefficacy, must be accurately assessed in order to plan the timely replacement of worn out nets and guide procurement of longer-lasting, cost-effective nets. World Health Organization (WHO) guidance advises that new intervention class ITNs be assessed 3 years after distribution, in experimental huts. In order to obtain information on whole-net efficacy cost-effectively and with adequate replication, a new bioassay, the Ifakara Ambient Chamber Test (I-ACT), a semi-field whole net assay baited with human host, was compared to established WHO durability testing methods. METHODS Two experiments were conducted using pyrethroid-susceptible female adult Anopheles gambiae sensu stricto comparing bioefficacy of Olyset®, PermaNet® 2.0 and NetProtect® evaluated by I-ACT and WHO cone and tunnel tests. In total, 432 nets (144/brand) were evaluated using I-ACT and cone test. Olyset® nets (132/144) that did not meet the WHO cone test threshold criteria (≥ 80% mortality or ≥ 95% knockdown) were evaluated using tunnel tests with threshold criteria of ≥ 80% mortality or ≥ 90% feeding inhibition for WHO tunnel and I-ACT. Pass rate of nets tested by WHO combined standard WHO bioassays (cone/tunnel tests) was compared to pass in I-ACT only by net brand and time after distribution. RESULTS Overall, more nets passed WHO threshold criteria when tested with I-ACT than with standard WHO bioassays 92% vs 69%, (OR: 4.1, 95% CI 3.5-4.7, p < 0.0001). The proportion of Olyset® nets that passed differed if WHO 2005 or WHO 2013 LN testing guidelines were followed: 77% vs 71%, respectively. Based on I-ACT results, PermaNet® 2.0 and NetProtect® demonstrated superior mortality and non-inferior feeding inhibition to Olyset® over 3 years of field use in Tanzania. CONCLUSION Ifakara Ambient Chamber Test may have use for durability studies and non-inferiority testing of new ITN products. It measures composite bioefficacy and physical integrity with both mortality and feeding inhibition endpoints, using fewer mosquitoes than standard WHO bioassays (cone and tunnel tests). The I-ACT is a high-throughput assay to evaluate ITN products that work through either contact toxicity or feeding inhibition. I-ACT allows mosquitoes to interact with a host sleeping underneath a net as encountered in the field, without risk to human participants.
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Affiliation(s)
- Dennis J Massue
- Epidemiology and Public Health Department, Swiss Institute of Tropical and Public Health, Soccinstrase 57, 4002, Basel, Switzerland.
- University of Basel, Petersplatz 1, 4003, Basel, Switzerland.
- National Institute for Medical Research, Amani Research Centre, P. O. Box 81, Muheza, Tanga, Tanzania.
- Ifakara Health Institute, P. O. Box 74, Bagamoyo, Pwani, Tanzania.
| | - Lena M Lorenz
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Jason D Moore
- Epidemiology and Public Health Department, Swiss Institute of Tropical and Public Health, Soccinstrase 57, 4002, Basel, Switzerland
- University of Basel, Petersplatz 1, 4003, Basel, Switzerland
- Ifakara Health Institute, P. O. Box 74, Bagamoyo, Pwani, Tanzania
| | | | - Samuel Ackerman
- Ifakara Health Institute, P. O. Box 74, Bagamoyo, Pwani, Tanzania
| | - Zawadi M Mboma
- Ifakara Health Institute, P. O. Box 74, Bagamoyo, Pwani, Tanzania
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - William N Kisinza
- National Institute for Medical Research, Amani Research Centre, P. O. Box 81, Muheza, Tanga, Tanzania
| | - Emmanuel Mbuba
- Ifakara Health Institute, P. O. Box 74, Bagamoyo, Pwani, Tanzania
| | - Selemani Mmbaga
- Ifakara Health Institute, P. O. Box 74, Bagamoyo, Pwani, Tanzania
| | - John Bradley
- MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Hans J Overgaard
- Faculty of Science and Technology, Norwegian University of Life Sciences, Ås, Norway
| | - Sarah J Moore
- Epidemiology and Public Health Department, Swiss Institute of Tropical and Public Health, Soccinstrase 57, 4002, Basel, Switzerland
- University of Basel, Petersplatz 1, 4003, Basel, Switzerland
- Ifakara Health Institute, P. O. Box 74, Bagamoyo, Pwani, Tanzania
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Solomon T, Loha E, Deressa W, Gari T, Overgaard HJ, Lindtjørn B. Low use of long-lasting insecticidal nets for malaria prevention in south-central Ethiopia: A community-based cohort study. PLoS One 2019; 14:e0210578. [PMID: 30629675 PMCID: PMC6328101 DOI: 10.1371/journal.pone.0210578] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 12/26/2018] [Indexed: 12/21/2022] Open
Abstract
Introduction A decline in malaria morbidity and mortality has been documented in Ethiopia since 2005 following a scale-up of the distribution of long-lasting insecticidal nets (LLINs). However, universal access to LLINs ownership and use has not yet been achieved. This study aimed to determine ownership and use of LLINs over time in south-central Ethiopia. Methods A cohort of 17,142 individuals residing in 3,006 households was followed-up from October 2014 to January 2017 (121 weeks). New PermaNet2.0 LLINs were given to households in October 2014. Once per week, the LLIN use status was documented for each individual. A survey was conducted after 110 weeks of LLIN distribution to determine LLIN ownership. A multilevel negative binomial regression model was fitted to identify significant predictors of LLIN use. Results At baseline, the LLIN ownership was 100%. After 110 weeks only 233 (8%) of the households owned at least one LLIN. The median proportion of LLIN use per individuals during the study period was only 14%. During the first year (week 1–52) the average LLIN use per individuals was 36% and during the second year (week 53–104) it was 4.6%. More frequent LLIN use was reported among age group [5–14 years (adjusted IRR = 1.13, 95% CI 1.04–1.22), 15–24 years (adjusted IRR = 1.33, 95% CI 1.23–1.45), ≥25 years (adjusted IRR = 1.99, 95% CI 1.83–2.17)] compared to <5 years, and household head educational status [read and write (adjusted IRR = 1.17, 95% CI 1.09–1.26), primary (adjusted IRR = 1.20, 95% CI 1.12–1.27), secondary or above (adjusted IRR = 1.20, 95% CI (1.11–1.30)] compared to illiterate. Having a family size of over five persons (adjusted IRR = 0.78, 95% CI 0.73–0.84) was associated with less frequent use of LLINs compared to a family size of ≤5 persons. Conclusions The study showed a low LLIN ownership after 110 weeks and a low LLIN use during 121 weeks of follow-up, despite 100% LLIN coverage at baseline. The study highlights the need to design strategies to increase LLIN ownership and use for setting similar to those studied here.
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Affiliation(s)
- Tarekegn Solomon
- School of Public Health, College of Medicine and Health Sciences, Hawassa University, Hawassa, Ethiopia
- Centre for International Health, University of Bergen, Bergen, Norway
- * E-mail:
| | - Eskindir Loha
- School of Public Health, College of Medicine and Health Sciences, Hawassa University, Hawassa, Ethiopia
| | - Wakgari Deressa
- Department of Preventive Medicine, School of Public Health, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Taye Gari
- School of Public Health, College of Medicine and Health Sciences, Hawassa University, Hawassa, Ethiopia
| | - Hans J. Overgaard
- Faculty of Science and Technology, Norwegian University of Life Sciences, Akershus, Norway
| | - Bernt Lindtjørn
- Centre for International Health, University of Bergen, Bergen, Norway
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Gonahasa S, Maiteki-Sebuguzi C, Rugnao S, Dorsey G, Opigo J, Yeka A, Katureebe A, Kyohere M, Lynd A, Hemingway J, Donnelly M, Kamya MR, Staedke SG. LLIN Evaluation in Uganda Project (LLINEUP): factors associated with ownership and use of long-lasting insecticidal nets in Uganda: a cross-sectional survey of 48 districts. Malar J 2018; 17:421. [PMID: 30424775 PMCID: PMC6234693 DOI: 10.1186/s12936-018-2571-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 11/03/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Long-lasting insecticidal nets (LLINs) are a key malaria control intervention. To investigate factors associated with ownership and use of LLINs in Uganda, a cross-sectional community survey was conducted in March-June 2017, approximately 3 years after a national Universal Coverage Campaign (UCC). METHODS Households from 104 clusters (health sub-districts) in 48 districts were randomly selected using two-staged cluster sampling; 50 households were enrolled per cluster. Outcomes were household ownership of LLINs (at least one LLIN), adequate LLIN coverage (at least one LLIN per 2 residents), and use of LLINs (resident slept under a LLIN the previous night). Associations between variables of interest and outcomes were made using multivariate logistic regression. RESULTS In total, 5196 households, with 29,627 residents and 6980 bed-nets, were included in the analysis. Overall, 65.0% of households owned at least one LLIN (down from 94% in 2014). In the adjusted analysis, factors most strongly associated with LLIN ownership were living in a wealthier household (highest tercile vs lowest; adjusted odds ratio [aOR] 1.94, 95% CI 1.66-2.28, p < 0.001) and time since the last UCC (29-37 vs 42-53 months; aOR 1.91, 95% CI 1.60-2.28, p < 0.001). Only 17.9% of households had adequate LLIN coverage (down from 65% in 2014). Factors most strongly associated with adequate coverage were fewer residents (2-4 vs ≥ 7; aOR 6.52, 95% CI 5.13-8.29, p < 0.001), living in a wealthier household (highest tercile vs lowest; aOR: 2,32, 95% CI 1.88-2.85, p < 0.001) and time since the last UCC (29-37 vs 42-53 months; aOR 2.13, 95% CI 1.61-2.81, p < 0.001). Only 39.5% of residents used a LLIN the previous night. Age was strongly associated with LLIN use, as were household wealth and time since the last UCC. Children < 5 years (44.7%) and residents > 15 years (44.1%) were more likely to use nets than children aged 5-15 years (30.7%; < 5 years: aOR 1.71, 95% CI 1.62-1.81, p < 0.001; > 15 years: aOR 1.37, 95% CI 1.29-1.45, p < 0.001). CONCLUSIONS Long-lasting insecticidal net ownership and coverage have reduced markedly in Uganda since the last net distribution campaign in 2013/14. Houses with many residents, poorer households, and school-aged children should be targeted to improve LLIN coverage and use. Trial registration This study is registered with ISRCTN (17516395).
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Affiliation(s)
- Samuel Gonahasa
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda.
| | - Catherine Maiteki-Sebuguzi
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda.,National Malaria Control Programme, Uganda Ministry of Health, Kampala, Uganda
| | - Sheila Rugnao
- University of California, San Francisco, San Francisco, CA, 94110, USA
| | - Grant Dorsey
- University of California, San Francisco, San Francisco, CA, 94110, USA
| | - Jimmy Opigo
- National Malaria Control Programme, Uganda Ministry of Health, Kampala, Uganda
| | - Adoke Yeka
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Agaba Katureebe
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Mary Kyohere
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Amy Lynd
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Janet Hemingway
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Martin Donnelly
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Sarah G Staedke
- London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
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Benelli G. Managing mosquitoes and ticks in a rapidly changing world - Facts and trends. Saudi J Biol Sci 2018; 26:921-929. [PMID: 31303820 PMCID: PMC6600734 DOI: 10.1016/j.sjbs.2018.06.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 06/06/2018] [Accepted: 06/26/2018] [Indexed: 02/08/2023] Open
Abstract
Vector-borne diseases transmitted by mosquitoes and ticks are on the rise. The effective and sustainable control of these arthropod vectors is a puzzling challenge for public health worldwide. In the present review, I attempted to provide a concise and updated overview of the current mosquito and tick research scenario. The wide array of control tools recently developed has been considered, with special reference to those approved by the World Health Organization Vector Control Advisory Group (WHO VCAG), as well as novel ones with an extremely promising potential to be exploited in vector control programs. Concerning mosquitoes, a major focus has been given on genetically modified vectors, eave tubes, attractive toxic sugar baits (ATSB) and biocontrol agents. Regarding ticks, the recent development of highly effective repellents and acaricides (including nanoformulated ones) as well as behavior-based control tools, has been highlighted. In the second part of the review, key research questions about biology and control of mosquitoes and ticks have been critically formulated. A timely research agenda outlining hot issues to be addressed in mosquito and tick research is provided. Overall, it is expected that the present review will contribute to boost research and applications on successful mosquito and tick control strategies, along with an improved knowledge of their biology and ecology.
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Affiliation(s)
- Giovanni Benelli
- Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124 Pisa, Italy.,The BioRobotics Institute, Sant'Anna School of Advanced Studies, viale Rinaldo Piaggio 34, 56025, Pontedera, Pisa, Italy
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Bed nets used to protect against malaria do not last long in a semi-arid area of Ethiopia: a cohort study. Malar J 2018; 17:239. [PMID: 29925371 PMCID: PMC6011348 DOI: 10.1186/s12936-018-2391-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Accepted: 06/14/2018] [Indexed: 11/29/2022] Open
Abstract
Background Long-lasting insecticidal nets (LLINs) are a key tool for malaria prevention and control. Currently, the recommended serviceable life of an LLIN is 3 years under field conditions. However, field studies show considerable variation in LLIN lifespan, from less than 2 years to more than 4 years. This study aimed to determine the attrition, physical integrity, functional survival, and bio-efficacy of LLINs under field conditions in south-central Ethiopia. Methods In October 2014, 7740 LLINs (PermaNet® 2.0) were distributed to 3006 households. Among the distributed LLINs, a cohort study involving 1532 LLINs in 659 households was carried out from October 2014 to November 2016. Data were collected every 6 months by observation, and through interviews with the heads of households. The proportional hole index was used to categorize LLINs as either serviceable or torn. In addition, 120 randomly selected LLINs were tested for bio-efficacy. Results The overall attrition of LLINs was 96% (n = 993) during the study period. The nets’ attrition was mainly due to disposal (64.2%; n = 638). The proportion of LLINs with a hole size 0.5 cm or larger was 79.5% after 24 months. The use of the net on the previous night and having a clean net were associated with a good physical integrity. However, living in a household more than 1 km away from the mosquitoes’ breeding site was associated with poor physical integrity. By the 24th month, only 4% of the nets met the criteria for functional survival. The median functional survival time of the nets was 12 months. A longer functional survival was associated with having a clean net, and shorter survival was associated with living in a household more than 1 km away from the mosquitoes’ breeding site. The PermaNet® 2.0 met the criteria of effective bio-efficacy up to month 24 after distribution. Conclusions The study showed that the median serviceable life of LLINs is only 12 months. However, the bio-efficacy of the LLINs is acceptable for at least 24 months. Therefore, stronger and more efficient LLINs need to be developed for conditions similar to those studied here.
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Prussing C, Moreno M, Saavedra MP, Bickersmith SA, Gamboa D, Alava F, Schlichting CD, Emerson KJ, Vinetz JM, Conn JE. Decreasing proportion of Anopheles darlingi biting outdoors between long-lasting insecticidal net distributions in peri-Iquitos, Amazonian Peru. Malar J 2018; 17:86. [PMID: 29463241 PMCID: PMC5819687 DOI: 10.1186/s12936-018-2234-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 02/13/2018] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND In Loreto Department, Peru, a successful 2005-2010 malaria control programme (known as PAMAFRO) included massive distribution of long-lasting insecticidal nets (LLINs). Additional local distribution of LLINs occurred in individual villages, but not between 2012 and 2015. A 2011-2012 study of the primary regional malaria vector Anopheles darlingi detected a trend of increased exophagy compared with pre-PAMAFRO behaviour. For the present study, An. darlingi were collected in three villages in Loreto in 2013-2015 to test two hypotheses: (1) that between LLIN distributions, An. darlingi reverted to pre-intervention biting behaviour; and, (2) that there are separate sub-populations of An. darlingi in Loreto with distinct biting behaviour. RESULTS In 2013-2015 An. darlingi were collected by human landing catch during the rainy and dry seasons in the villages of Lupuna and Cahuide. The abundance of An. darlingi varied substantially across years, villages and time periods, and there was a twofold decrease in the ratio of exophagic:endophagic An. darlingi over the study period. Unexpectedly, there was evidence of a rainy season population decline in An. darlingi. Plasmodium-infected An. darlingi were detected indoors and outdoors throughout the night, and the monthly An. darlingi human biting rate was correlated with the number of malaria cases. Using nextRAD genotyping-by-sequencing, 162 exophagic and endophagic An. darlingi collected at different times during the night were genotyped at 1021 loci. Based on model-based and non-model-based analyses, all genotyped An. darlingi belonged to a homogeneous population, with no evidence for genetic differentiation by biting location or time. CONCLUSIONS This study identified a decreasing proportion of exophagic An. darlingi in two villages in the years between LLIN distributions. As there was no evidence for genetic differentiation between endophagic and exophagic An. darlingi, this shift in biting behaviour may be the result of behavioural plasticity in An. darlingi, which shifted towards increased exophagy due to repellence by insecticides used to impregnate LLINs and subsequently reverted to increased endophagy as the nets aged. This study highlights the need to target vector control interventions to the biting behaviour of local vectors, which, like malaria risk, shows high temporal and spatial heterogeneity.
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Affiliation(s)
- Catharine Prussing
- Department of Biomedical Sciences, School of Public Health, University at Albany - State University of New York, Albany, NY, USA
| | - Marta Moreno
- Division of Infectious Diseases, Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Marlon P Saavedra
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigacion y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | | | - Dionicia Gamboa
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigacion y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
- Instituto de Medicina Tropical "Alexander von Humboldt", Universidad Peruana Cayetano Heredia, Lima, Peru
| | | | - Carl D Schlichting
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, USA
| | - Kevin J Emerson
- Department of Biology, St. Mary's College of Maryland, St. Mary's City, MD, USA
| | - Joseph M Vinetz
- Division of Infectious Diseases, Department of Medicine, University of California San Diego, La Jolla, CA, USA
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigacion y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Jan E Conn
- Department of Biomedical Sciences, School of Public Health, University at Albany - State University of New York, Albany, NY, USA.
- Wadsworth Center, New York State Department of Health, Albany, NY, USA.
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Randriamaherijaona S, Raharinjatovo J, Boyer S. Durability monitoring of long-lasting insecticidal (mosquito) nets (LLINs) in Madagascar: physical integrity and insecticidal activity. Parasit Vectors 2017; 10:564. [PMID: 29132421 PMCID: PMC5683549 DOI: 10.1186/s13071-017-2419-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 10/03/2017] [Indexed: 11/10/2022] Open
Abstract
Background Long-lasting insecticidal mosquito nets (LLINs) are highly effective for malaria prevention. However, it is also clear that durability monitoring is essential to predict when, post-distribution, a net population, no longer meets minimum WHO standards and needs to be replaced. Following a national distribution campaign in 2013, we tracked two durability indicators, physical integrity and bio-efficacy at six and 12 months post-distribution. While the loss of net integrity during this period was in line with expectations for a one-year net life, bio-efficacy results suggested that nets were losing insecticidal effect faster than expected. The rate of bio-efficacy loss varied significantly between different net brands. Methods We tested 600 randomly selected LLINs, 200 from each of three net brands. Each brand came from different eco-epidemiological zones reflecting the original distribution scheme. Fabric integrity (size and number of holes) was quantified using the proportional hole index (pHI). A subsample of the nets, 134 new nets, 150 at six months and 124 at 12 months, were then tested for bio-efficacy using the World Health Organization (WHO) recommended method. Results Three net types, Netprotect®, Royalsentry® and Yorkool®, were followed. After six months, 54%, 39% and 45%, respectively, showed visible loss of integrity. The median pHI by type was estimated to be one, zero and one respectively. The percentage of damaged nets increased after 12 months such that 83.5%, 74% and 68.5%, had holes. The median pHI for each brand of nets was 47.5, 47 and 23. No significant difference in the estimated pHI at either six or 12 months was observed. There was a statistically significant difference in the proportion of hole size category between the three brands (χ2 = 15.761, df = 4, P = 0.003). In cone bio-assays, mortality of new Yorkool® nets was surprisingly low (48.6%), mortality was 90.2% and 91.3% for Netprotect® and Royalsentry® (F(2, 131) = 81.59, P < 0.0001), respectively. At 12 month use, all tested nets were below the WHO threshold for replacement. Conclusion These findings suggest that there is a need for better net quality control before distribution. More frequent replacement of LLINs is probably not an option programmatically. Regardless of prior approval, LLIN durability monitoring for quality assessment as well as net loss following distribution is necessary to improve malaria control efforts. Electronic supplementary material The online version of this article (10.1186/s13071-017-2419-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sanjiarizaha Randriamaherijaona
- Unité d'Entomologie Médicale, Institut Pasteur de Madagascar, 1274 Avaradoha, 101, Antananarivo, BP, Madagascar. .,Ecole doctorale Sciences de la vie et de l'environnement, Université d'Antananarivo, 101, Antananarivo, Madagascar.
| | - Jacky Raharinjatovo
- Population Services International Madagascar, 7748 Ampefiloha, 101, Antananarivo, BP, Madagascar
| | - Sébastien Boyer
- Medical Entomology Platform, Institute Pasteur of Cambodia, 5 Preah Monivong Blvd (93), Phnom Penh, Cambodia
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Vanden Eng JL, Mathanga DP, Landman K, Mwandama D, Minta AA, Shah M, Sutcliffe J, Chisaka J, Lindblade KA, Steinhardt L. Assessing bed net damage: comparisons of three measurement methods for estimating the size, shape, and distribution of holes on bed nets. Malar J 2017; 16:405. [PMID: 29017537 PMCID: PMC5635507 DOI: 10.1186/s12936-017-2049-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 09/30/2017] [Indexed: 11/23/2022] Open
Abstract
Background Measuring the physical condition of long-lasting insecticidal nets (LLINs) under field conditions is of great importance for malaria control programmes to guide decisions on how frequently to replace LLINs. Current guidelines by the World Health Organization Pesticide Evaluation Scheme (WHOPES) propose a proportionate hole index (pHI) for assessing LLIN condition by counting the number of holes the size of a thumb, fist, head, and larger than a head. However, this method does not account for irregular hole shapes or exact hole sizes which could result in inaccurate decisions about when to replace LLINs. Methods LLINs were collected during a 2013 health facility-based malaria case control study in Machinga District, Malawi. To evaluate the accuracy of the pHI, the physical condition of 277 LLINs was estimated by the WHOPES method and then compared with two more thorough measurement methods: image analysis of digital photographs of each LLIN side; and for 10 nets, ruler measurements of the length, width, and location of each hole. Total hole counts and areas per net were estimated by each method, and detailed results of hole shapes and composite pictures of hole locations were generated using image analysis. Results The WHOPES method and image analysis resulted in similar estimates of total hole counts, each with a median of 10 (inter-quartile range (IQR) 4–24 and 4–23, respectively; p = 0.004); however, estimated hole areas were significantly larger using the WHOPES method (median 162 cm2, IQR 28–793) than image analysis (median 13 cm2, IQR 3–101; p < 0.0001). The WHOPES method classified fewer LLINs in ‘good condition’ compared to image analysis (42% vs 74%). The ruler method detected significantly more holes than image analysis did (p = 0.002) in 10 LLINs; however, total hole area was not significantly different (p = 0.16). Most holes were not circular but roughly 2–5 times longer in one direction. The lower quarter of LLIN sides was found to have the most holes. Conclusions The WHOPES method overestimated total hole area, likely because holes are elongated rather than circular, suggesting further adjustments to the pHI formula may be warranted when considering LLIN replacement strategies. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-2049-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jodi L Vanden Eng
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA.
| | - Don P Mathanga
- Malaria Alert Centre, University of Malawi College of Medicine, Blantyre, Malawi
| | - Keren Landman
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - Dyson Mwandama
- Malaria Alert Centre, University of Malawi College of Medicine, Blantyre, Malawi
| | - Anna A Minta
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA.,Epidemic Intelligence Service, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - Monica Shah
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - James Sutcliffe
- Entomology Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - Joseph Chisaka
- Malaria Alert Centre, University of Malawi College of Medicine, Blantyre, Malawi
| | - Kim A Lindblade
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - Laura Steinhardt
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
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48
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Minta AA, Landman KZ, Mwandama DA, Shah MP, Eng JLV, Sutcliffe JF, Chisaka J, Lindblade KA, Mathanga DP, Steinhardt LC. The effect of holes in long-lasting insecticidal nets on malaria in Malawi: results from a case-control study. Malar J 2017; 16:394. [PMID: 28969632 PMCID: PMC5625742 DOI: 10.1186/s12936-017-2033-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 09/18/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Long-lasting insecticidal nets (LLINs) are a cornerstone of malaria prevention. Holes develop in LLINs over time and compromise their physical integrity, but how holes affect malaria transmission risk is not well known. METHODS After a nationwide mass LLIN distribution in July 2012, a study was conducted to assess the relationship between LLIN damage and malaria. From March to September 2013, febrile children ages 6-59 months who consistently slept under LLINs (every night for 2 weeks before illness onset) were enrolled in a case-control study at Machinga District Hospital outpatient department. Cases were positive for Plasmodium falciparum asexual parasites by microscopy while controls were negative. Digital photographs of participants' LLINs were analysed using an image-processing programme to measure holes. Total hole area was classified by quartiles and according to the World Health Organization's proportionate hole index (pHI) cut-offs [< 79 cm2 (good), 80-789 cm2 (damaged), and > 790 cm2 (too torn)]. Number of holes by location and size, and total hole area, were compared between case and control LLINs using non-parametric analyses and logistic regression. RESULTS Of 248 LLINs analysed, 97 (39%) were from cases. Overall, 86% of LLINs had at least one hole. The median number of holes of any size was 9 [interquartile range (IQR) 3, 22], and most holes were located in the lower halves of the nets [median 7 (IQR 2, 16)]. There were no differences in number or location of holes between LLINs used by cases and controls. The median total hole area was 10 cm2 (IQR 2, 125) for control LLINs and 8 cm2 (IQR 2, 47) for case LLINs (p = 0.10). Based on pHI, 109 (72%) control LLINs and 83 (86%) case LLINs were in "good" condition. Multivariable modeling showed no association between total hole area and malaria, controlling for child age, caregiver education, and iron versus thatched roof houses. CONCLUSIONS LLIN holes were not associated with increased odds of malaria in this study. However, most of the LLINs were in relatively good condition 1 year after distribution. Future studies should examine associations between LLIN holes and malaria risk with more damaged nets.
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Affiliation(s)
- Anna A Minta
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA. .,Epidemic Intelligence Service, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA.
| | - Keren Z Landman
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - Dyson A Mwandama
- Malaria Alert Centre, University of Malawi College of Medicine, Private Bag 360, Blantyre, Malawi
| | - Monica P Shah
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - Jodi L Vanden Eng
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - James F Sutcliffe
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - Joseph Chisaka
- Malaria Alert Centre, University of Malawi College of Medicine, Private Bag 360, Blantyre, Malawi
| | - Kim A Lindblade
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - Don P Mathanga
- Malaria Alert Centre, University of Malawi College of Medicine, Private Bag 360, Blantyre, Malawi
| | - Laura C Steinhardt
- Malaria Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
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49
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Zewde A, Irish S, Woyessa A, Wuletaw Y, Nahusenay H, Abdelmenan S, Demissie M, Gulema H, Dissanayake G, Chibsa S, Solomon H, Yenehun MA, Kebede A, Lorenz LM, Ponce-de-Leon G, Keating J, Worku A, Berhane Y. Knowledge and perception towards net care and repair practice in Ethiopia. Malar J 2017; 16:396. [PMID: 28969636 PMCID: PMC5625612 DOI: 10.1186/s12936-017-2043-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 09/21/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Long-lasting insecticidal nets (LLINs) are a key malaria control intervention. Although LLINs are presumed to be effective for 3 years under field or programmatic conditions, net care and repair approaches by users influence the physical and chemical durability. Understanding how knowledge, perception and practices influence net care and repair practices could guide the development of targeted behavioural change communication interventions related to net care and repair in Ethiopia and elsewhere. METHODS This population-based, household survey was conducted in four regions of Ethiopia [Amhara, Oromia, Tigray, Southern Nations Nationalities Peoples Region (SNNPR)] in June 2015. A total of 1839 households were selected using multi-stage sampling procedures. The household respondents were the heads of households. A questionnaire was administered and the data were captured electronically. STATA software version 12 was used to analyse the data. Survey commands were used to account for the multi-stage sampling approach. Household descriptive statistics related to characteristics and levels of knowledge and perception on net care and repair are presented. Ordinal logistic regression was used to identify factors associated with net care and repair perceptions. RESULTS Less than a quarter of the respondents (22.3%: 95% CI 20.4-24.3%) reported adequate knowledge of net care and repair; 24.6% (95% CI 22.7-26.5%) of the respondents reported receiving information on net care and repair in the previous 6 months. Thirty-five per cent of the respondents (35.1%: 95% CI 32.9-37.4%) reported positive perceptions towards net care and repair. Respondents with adequate knowledge on net care and repair (AOR 1.58: 95% CI 1.2-2.02), and those who discussed net care and repair with their family (AOR 1.47: 95% CI 1.14-1.89) had higher odds of having positive perceptions towards net care and repair. CONCLUSIONS The low level of reported knowledge on net care and repair, as well as the low level of reported positive perception towards net repair need to be addressed. Targeted behavioural change communication campaigns could be used to target specific groups; increased net care and repair would lead to longer lasting nets.
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Affiliation(s)
- Ayele Zewde
- Addis Continental Institute of Public Health, Addis Ababa, Ethiopia
| | - Seth Irish
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention and U.S. President's Malaria Initiative, Atlanta, USA
| | - Adugna Woyessa
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Yonas Wuletaw
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Honelgn Nahusenay
- Addis Continental Institute of Public Health, Addis Ababa, Ethiopia.
| | | | - Meaza Demissie
- Addis Continental Institute of Public Health, Addis Ababa, Ethiopia
| | - Hanna Gulema
- Addis Continental Institute of Public Health, Addis Ababa, Ethiopia
| | | | - Sheleme Chibsa
- President Malaria Initiative (PMI-USAID), Addis Ababa, Ethiopia
| | - Hiwot Solomon
- Ethiopian National Malaria Prevention, Control and Elimination Program, Addis Ababa, Ethiopia
| | - Meseret A Yenehun
- Ethiopian National Malaria Prevention, Control and Elimination Program, Addis Ababa, Ethiopia
| | - Amha Kebede
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Lena M Lorenz
- London School of Hygiene and Tropical Medicine, London, UK
| | | | - Joseph Keating
- School of Public Health and Tropical Medicine, Tulane University, New Orleans, USA
| | - Alemayehu Worku
- Addis Continental Institute of Public Health, Addis Ababa, Ethiopia
| | - Yemane Berhane
- Addis Continental Institute of Public Health, Addis Ababa, Ethiopia
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50
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McCann RS, van den Berg H, Diggle PJ, van Vugt M, Terlouw DJ, Phiri KS, Di Pasquale A, Maire N, Gowelo S, Mburu MM, Kabaghe AN, Mzilahowa T, Chipeta MG, Takken W. Assessment of the effect of larval source management and house improvement on malaria transmission when added to standard malaria control strategies in southern Malawi: study protocol for a cluster-randomised controlled trial. BMC Infect Dis 2017; 17:639. [PMID: 28938876 PMCID: PMC5610449 DOI: 10.1186/s12879-017-2749-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 09/19/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Due to outdoor and residual transmission and insecticide resistance, long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) will be insufficient as stand-alone malaria vector control interventions in many settings as programmes shift toward malaria elimination. Combining additional vector control interventions as part of an integrated strategy would potentially overcome these challenges. Larval source management (LSM) and structural house improvements (HI) are appealing as additional components of an integrated vector management plan because of their long histories of use, evidence on effectiveness in appropriate settings, and unique modes of action compared to LLINs and IRS. Implementation of LSM and HI through a community-based approach could provide a path for rolling-out these interventions sustainably and on a large scale. METHODS/DESIGN We will implement community-based LSM and HI, as additional interventions to the current national malaria control strategies, using a randomised block, 2 × 2 factorial, cluster-randomised design in rural, southern Malawi. These interventions will be continued for two years. The trial catchment area covers about 25,000 people living in 65 villages. Community participation is encouraged by training community volunteers as health animators, and supporting the organisation of village-level committees in collaboration with The Hunger Project, a non-governmental organisation. Household-level cross-sectional surveys, including parasitological and entomological sampling, will be conducted on a rolling, 2-monthly schedule to measure outcomes over two years (2016 to 2018). Coverage of LSM and HI will also be assessed throughout the trial area. DISCUSSION Combining LSM and/or HI together with the interventions currently implemented by the Malawi National Malaria Control Programme is anticipated to reduce malaria transmission below the level reached by current interventions alone. Implementation of LSM and HI through a community-based approach provides an opportunity for optimum adaptation to the local ecological and social setting, and enhances the potential for sustainability. TRIAL REGISTRATION Registered with The Pan African Clinical Trials Registry on 3 March 2016, trial number PACTR201604001501493.
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Affiliation(s)
- Robert S McCann
- Wageningen University and Research, Wageningen, The Netherlands. .,College of Medicine, University of Malawi, Blantyre, Malawi. .,Laboratory of Entomology, Wageningen University and Research, PO Box 16, 6700, AA, Wageningen, The Netherlands.
| | | | | | - Michèle van Vugt
- Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Dianne J Terlouw
- Liverpool School of Tropical Medicine, Liverpool, UK.,Malawi-Liverpool Wellcome Trust, Blantyre, Malawi
| | - Kamija S Phiri
- College of Medicine, University of Malawi, Blantyre, Malawi
| | - Aurelio Di Pasquale
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Nicolas Maire
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Steven Gowelo
- College of Medicine, University of Malawi, Blantyre, Malawi
| | - Monicah M Mburu
- Wageningen University and Research, Wageningen, The Netherlands.,College of Medicine, University of Malawi, Blantyre, Malawi
| | - Alinune N Kabaghe
- College of Medicine, University of Malawi, Blantyre, Malawi.,Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Michael G Chipeta
- College of Medicine, University of Malawi, Blantyre, Malawi.,Lancaster University, Lancaster, UK.,Malawi-Liverpool Wellcome Trust, Blantyre, Malawi
| | - Willem Takken
- Wageningen University and Research, Wageningen, The Netherlands
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