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Nawa M, Mupeyo-Mudala C, Banda-Tembo S, Adetokunboh O. The effects of modern housing on malaria transmission in different endemic zones: a systematic review and meta-analysis. Malar J 2024; 23:235. [PMID: 39113048 PMCID: PMC11308589 DOI: 10.1186/s12936-024-05059-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Accepted: 07/27/2024] [Indexed: 08/10/2024] Open
Abstract
BACKGROUND Modern housing has been shown to reduce the risk of malaria infections compared to traditional houses; however, it is unclear if the effects differ in different malaria transmission settings. This study evaluated the effects of modern housing on malaria among different endemic areas. METHODS Electronic databases, clinical trial registries and grey literature were searched for randomized controlled trials, cohort studies, case-control studies, and cross-sectional surveys on housing done between 1987 and 2022. Forest plots were done, and the quality of evidence was assessed using the Grading of Recommendations, Assessments, Development and Evaluation Framework. RESULTS Twenty-one studies were included; thirteen were cross-sectional, four were case-control and four were cohort studies. Cohort studies showed an adjusted risk ratio of 0.68 (95% CI 0.48-0.96), and cross-sectional studies indicated an adjusted odds ratio (aOR) of 0.79 (95%CI 0.75-0.83). By endemic transmission regions, the adjusted odds ratio in the high endemic settings was 0.80 (95%CI 0.76-085); in the moderate transmission regions, aOR = 0.76 (95%CI 0.67-0.85) and in the low transmission settings, aOR = 0.67 (95%CI 0.48-0.85). CONCLUSIONS The evidence from observational studies suggests that there are no differences in the protective effects of modern houses compared to traditional houses on malaria by endemicity level. This implies that good quality modern housing protects against malaria regardless of the malaria transmission settings.
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Affiliation(s)
- Mukumbuta Nawa
- Division of Epidemiology and Biostatistics, Stellenbosch University, Stellenbosch, Western Cape, South Africa.
- Department of Epidemiology and Biostatistics, Levy Mwanawasa Medical University, Lusaka, Zambia.
| | - Catherine Mupeyo-Mudala
- Department of Epidemiology and Biostatistics, Levy Mwanawasa Medical University, Lusaka, Zambia
| | - Sylvia Banda-Tembo
- Department of Epidemiology and Biostatistics, Levy Mwanawasa Medical University, Lusaka, Zambia
| | - Olatunji Adetokunboh
- Division of Epidemiology and Biostatistics, Stellenbosch University, Stellenbosch, Western Cape, South Africa
- DSI-NRF Centre of Excellence in Epidemiological Modelling and Analysis (SACEMA), Stellenbosch University, Stellenbosch, Western Cape, South Africa
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Nankabirwa JI, Gonahasa S, Katureebe A, Mutungi P, Nassali M, Kamya MR, Westercamp N. The Uganda housing modification study - association between housing characteristics and malaria burden in a moderate to high transmission setting in Uganda. Malar J 2024; 23:223. [PMID: 39080697 PMCID: PMC11290271 DOI: 10.1186/s12936-024-05051-5] [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: 04/24/2024] [Accepted: 07/20/2024] [Indexed: 08/02/2024] Open
Abstract
BACKGROUND Scale up of proven malaria control interventions has not been sufficient to control malaria in Uganda, emphasizing the need to explore innovative new approaches. Improved housing is one such promising strategy. This paper describes housing characteristics and their association with malaria burden in a moderate to high transmission setting in Uganda. METHODS Between October and November 2021, a household survey was conducted in 1500 randomly selected households in Jinja and Luuka districts. Information on demographics, housing characteristics, use of malaria prevention measures, and proxy indicators of wealth were collected for each household. A finger-prick blood sample was obtained for thick blood smears for malaria from all children aged 6 months to 14 years in the surveyed households. Febrile children had a malaria rapid diagnostics test (RDT) done; positive cases were managed according to national treatment guidelines. Haemoglobin was assessed in children aged < 5 years. Households were stratified as having modern houses (defined as having finished materials for roofs, walls, and floors and closed eaves) or traditional houses (those not meeting the definition of modern house). Associations between malaria burden and house type were estimated using mixed effects models and adjusted for age, wealth, and bed net use. RESULTS Most (65.5%) of the households surveyed lived in traditional houses. Most of the houses had closed eaves (85.5%), however, the use of other protective features like window/vent screens and installed ceilings was limited (0.4% had screened windows, 2.8% had screened air vents, and 5.2% had ceiling). Overall, 3,443 children were included in the clinical survey, of which 31.4% had a positive smear. RDT test positivity rate was 56.6% among children with fever. Participants living in modern houses had a significantly lower parasite prevalence by microscopy (adjusted prevalence ratio [aPR = 0.80]; 95% confidence interval [CI] 0.71 - 0.90), RDT test positivity rate (aPR = 0.90, 95%CI 0.81 - 0.99), and anaemia (aPR = 0.80, 95%CI 0.65 - 0.97) compared to those in traditional houses. CONCLUSION The study found that even after adjusting for wealth, higher quality housing had a moderate protective effect against malaria, on top of the protection already afforded by recently distributed nets.
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Affiliation(s)
- Joaniter I Nankabirwa
- Infectious Diseases Research Collaboration, Kampala, Uganda.
- Department of Internal Medicine, Makerere University College of Health Science, Kampala, Uganda.
| | | | | | - Peter Mutungi
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Martha Nassali
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda
- Department of Internal Medicine, Makerere University College of Health Science, Kampala, Uganda
| | - Nelli Westercamp
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia
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Gonahasa S, Nassali M, Maiteki-Sebuguzi C, Namuganga JF, Opigo J, Nabende I, Okiring J, Epstein A, Snyman K, Nankabirwa JI, Kamya MR, Dorsey G, Staedke SG. LLIN evaluation in Uganda project (LLINEUP2): association between housing construction and malaria burden in 32 districts. Malar J 2024; 23:190. [PMID: 38886782 PMCID: PMC11181653 DOI: 10.1186/s12936-024-05012-y] [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: 02/21/2024] [Accepted: 06/08/2024] [Indexed: 06/20/2024] Open
Abstract
BACKGROUND Well-built housing limits mosquito entry and can reduce malaria transmission. The association between community-level housing and malaria burden in Uganda was assessed using data from randomly selected households near 64 health facilities in 32 districts. METHODS Houses were classified as 'improved' (synthetic walls and roofs, eaves closed or absent) or 'less-improved' (all other construction). Associations between housing and parasitaemia were made using mixed effects logistic regression (individual-level) and multivariable fractional response logistic regression (community-level), and between housing and malaria incidence using multivariable Poisson regression. RESULTS Between November 2021 and March 2022, 4.893 children aged 2-10 years were enrolled from 3.518 houses; of these, 1.389 (39.5%) were classified as improved. Children living in improved houses had 58% lower odds (adjusted odds ratio = 0.42, 95% CI 0.33-0.53, p < 0.0001) of parasitaemia than children living in less-improved houses. Communities with > 67% of houses improved had a 63% lower parasite prevalence (adjusted prevalence ratio 0.37, 95% CI 0.19-0.70, p < 0.0021) and 60% lower malaria incidence (adjusted incidence rate ratio 0.40, 95% CI 0.36-0.44, p < 0.0001) compared to communities with < 39% of houses improved. CONCLUSIONS Improved housing was strongly associated with lower malaria burden across a range of settings in Uganda and should be utilized for malaria control.
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Affiliation(s)
- Samuel Gonahasa
- Infectious Diseases Research Collaboration, Kampala, Uganda.
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Martha Nassali
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Catherine Maiteki-Sebuguzi
- Infectious Diseases Research Collaboration, Kampala, Uganda
- National Malaria Control Division, Ministry of Health, Kampala, Uganda
| | | | - Jimmy Opigo
- National Malaria Control Division, Ministry of Health, Kampala, Uganda
| | - Isaiah Nabende
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Jaffer Okiring
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Adrienne Epstein
- Department of Medicine, University of California San Francisco, San Francisco, USA
| | - Katherine Snyman
- Infectious Diseases Research Collaboration, Kampala, Uganda
- Department of Global Health and Development, London School of Hygiene & Tropical Medicine, London, UK
- Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, UK
| | - Joaniter I Nankabirwa
- Infectious Diseases Research Collaboration, Kampala, Uganda
- Department of Medicine, Makerere University, Kampala, Uganda
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda
- Department of Medicine, Makerere University, Kampala, Uganda
| | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, USA
| | - Sarah G Staedke
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
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Mponzi WP, Msaky DS, Binyaruka P, Kaindoa EW. Exploring the potential of village community banking as a community-based financing system for house improvements and malaria vector control in rural Tanzania. PLOS GLOBAL PUBLIC HEALTH 2023; 3:e0002395. [PMID: 37922222 PMCID: PMC10624283 DOI: 10.1371/journal.pgph.0002395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 10/09/2023] [Indexed: 11/05/2023]
Abstract
House improvement is associated with remarkable reductions in indoor mosquito bites and disease incidences, even in typical rural houses. However, its exploitation remains extremely poor in Tanzania and other endemic countries due to limited financial resources. Nevertheless, village community banks (VICOBA), practiced in Tanzania for nearly two decades, have proven to provide financial services to rural communities that would otherwise not be able to get them from formal financial institutions. This study explored the need, opinion, and willingness of VICOBA members to use VICOBA platforms as a source of finance for improving local houses and eventually controlling mosquito-borne diseases. A mixed-methods approach was used in this study, whereby a survey was administered to 150 participants and twelve focus group discussions were done in three villages in Ulanga district, rural Tanzania. The FGDs comprised eight participants each, with equal representation of males and females. The FGD guide was used to probe the opinions of study participants on malaria transmission, housing condition improvements, and financial resources. About 99% of all participants indicated the urgent need to improve their houses to prevent mosquito bites and were willing to utilize VICOBA for improving their houses. In the focus group discussion, the majority of people who participated were also in need of improving their houses. All participants confirmed that they were at the highest risk of getting mosquito-borne diseases, and they were willing to use money that was either saved or borrowed from their VICOBA for housing improvements and vector control. A self-sustaining financial system destined for house improvement and related interventions against malaria and other mosquito-borne diseases is crucial. The community members were willing to use VICOBA as a source of finance for house improvement and disease control; however, there was limited knowledge and sensitization on how they could utilize VICOBA for disease control.
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Affiliation(s)
- Winifrida P. Mponzi
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Dickson S. Msaky
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- The Nelson Mandela, African Institution of Science and Technology, School of Life Sciences and Bio Engineering, Tengeru, Arusha, United Republic of Tanzania
| | - Peter Binyaruka
- Department of Health System, Impact Evaluation and Policy, Ifakara Health Institute, Dar es Salaam, Tanzania
| | - Emmanuel W. Kaindoa
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- The Nelson Mandela, African Institution of Science and Technology, School of Life Sciences and Bio Engineering, Tengeru, Arusha, United Republic of Tanzania
- School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa
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Kihwele F, Gavana T, Makungu C, Msuya HM, Mlacha YP, Govella NJ, Chaki PP, Sunguya BF. Exploring activities and behaviours potentially increases school-age children's vulnerability to malaria infections in south-eastern Tanzania. Malar J 2023; 22:293. [PMID: 37789435 PMCID: PMC10548596 DOI: 10.1186/s12936-023-04703-2] [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: 04/18/2023] [Accepted: 09/02/2023] [Indexed: 10/05/2023] Open
Abstract
BACKGROUND Strengthening malaria control activities in Tanzania has dramatically declined human malaria infections. However, there is an increasing epidemiological shift in the burden on school-age children. The underlying causes for such an epidemiological shift remain unknown in this context. This study explored activities and behaviours that could increase the vulnerability of school-age children to transmission risk to provide insight into protection gap with existing interventions and opportunities for supplementary interventions. METHODS This cross-sectional study conducted twenty-four focus group discussions (FGDs) in three districts of Rufiji, Kibiti and Kilwa in south-eastern Tanzania. Sixteen FGDs worked with school-age children (13 to 18 years) separating girls and boys and eight FGDs with their parents in mixed-gender groups. A total of 205 community members participated in FGDs across the study area. Of them, 72 participants were parents, while 133 were school-age children (65 boys and 68 girls). RESULTS Routine domestic activities such as fetching water, washing kitchen utensils, cooking, and recreational activities such as playing and watching television and studying were the reported activities that kept school-age children outdoors early evening to night hours (between 18:00 and 23:00). Likewise, the social and cultural events including initiation ceremonies and livelihood activities also kept this age group outdoors from late evening to early night and sometimes past midnight hours. Parents migrating to farms from December to June, leaving behind school-age children unsupervised affecting their net use behaviour plus spending more time outdoors at night, and the behaviour of children sprawling legs and hands while sleeping inside treated bed nets were identified as potential risks to infectious mosquito bites. CONCLUSION The risky activities, behaviours, and social events mostly occurring outdoors might increase school-age children's vulnerability to malaria infections. The findings provide preliminary insight on potential risk factors for persisting transmission. Further studies to quantify the risk behaviour and activities are recommended to establish the magnitude and anticipated impact on supplementary control strategies to control infection in school-age children.
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Affiliation(s)
- Fadhila Kihwele
- Environmental Health and Ecological Sciences Department, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78373, Dar Es Salaam, United Republic of Tanzania.
- Muhimbili University of Health and Allied Sciences, P.O. Box 65001, Dar es Salaam, United Republic of Tanzania.
| | - Tegemeo Gavana
- Environmental Health and Ecological Sciences Department, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78373, Dar Es Salaam, United Republic of Tanzania
- Muhimbili University of Health and Allied Sciences, P.O. Box 65001, Dar es Salaam, United Republic of Tanzania
| | - Christina Makungu
- Environmental Health and Ecological Sciences Department, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78373, Dar Es Salaam, United Republic of Tanzania
| | - Hajirani M Msuya
- Environmental Health and Ecological Sciences Department, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78373, Dar Es Salaam, United Republic of Tanzania
| | - Yeromin P Mlacha
- Environmental Health and Ecological Sciences Department, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78373, Dar Es Salaam, United Republic of Tanzania
| | - Nicodem James Govella
- Environmental Health and Ecological Sciences Department, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78373, Dar Es Salaam, United Republic of Tanzania
- School of Life Sciences and Bioengineering (LISBE), Nelson Mandela African Institution of Science and Technology, P.O. BOX 447, Tengeru, Arusha, United Republic of Tanzania
| | - Prosper Pius Chaki
- Environmental Health and Ecological Sciences Department, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78373, Dar Es Salaam, United Republic of Tanzania
- The Pan African Mosquito Control Association (PAMCA), KEMRI Headquarters, Mbagathi Road Nairobi, Nairobi, 54840-00200, Kenya
| | - Bruno Fokas Sunguya
- Muhimbili University of Health and Allied Sciences, P.O. Box 65001, Dar es Salaam, United Republic of Tanzania
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Kayendeke M, Nabirye C, Nayiga S, Westercamp N, Gonahasa S, Katureebe A, Kamya MR, Staedke SG, Hutchinson E. House modifications as a malaria control tool: how does local context shape participants' experience and interpretation in Uganda? Malar J 2023; 22:244. [PMID: 37626312 PMCID: PMC10463640 DOI: 10.1186/s12936-023-04669-1] [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: 01/27/2023] [Accepted: 08/07/2023] [Indexed: 08/27/2023] Open
Abstract
BACKGROUND Evidence that house design can provide protection from malaria is growing. Housing modifications such as screening windows, doors, and ceilings, and attaching insecticide-impregnated materials to the eaves (the gap between the top of the wall and bottom of the roof), can protect against malaria. To be effective at scale, however, these modifications must be adopted by household residents. There is evidence that housing modifications can be acceptable, but in-depth knowledge on the experiences and interpretation of modifications is lacking. This qualitative study was carried out to provide a holistic account of the relationship between experiences and interpretations of four types of piloted housing modifications and the local context in Jinja, Uganda. METHODS Qualitative research was conducted between January to June 2021, before and during the installation of four types of housing modifications. The methods included nine weeks of participant observations in two study villages, nine focus group discussions with primary caregivers and heads of households (11-12 participants each), and nine key informant interviews with stakeholders and study team members. RESULTS Most residents supported the modifications. Experiences and interpretation of the housing modifications were shaped by the different types of housing in the area and the processes through which residents finished their houses, local forms of land and property ownership, and cultural and spiritual beliefs about houses. CONCLUSIONS To maximize the uptake and benefit of housing modifications against malaria, programme development needs to take local context into account. Forms of local land and house ownership, preferences, the social significance of housing types, and religious and spiritual ideas shape the responses to housing modifications in Jinja. These factors may be important in other setting. Trial registration Trial registration number is NCT04622241. The first draft was posted on November 9th 2020.
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Affiliation(s)
| | - Christine Nabirye
- Infectious Diseases Research Collaboration, Kampala, Uganda
- London School of Hygiene and Tropical Medicine, London, UK
| | - Susan Nayiga
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Nelli Westercamp
- Malaria Branch, Centers for Disease Control and Prevention, Atlanta, USA
| | | | | | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda
- Department of Medicine, Makerere University, Kampala, Uganda
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Chilot D, Mondelaers A, Alem AZ, Asres MS, Yimer MA, Toni AT, Ayele TA. Pooled prevalence and risk factors of malaria among children aged 6-59 months in 13 sub-Saharan African countries: A multilevel analysis using recent malaria indicator surveys. PLoS One 2023; 18:e0285265. [PMID: 37256889 DOI: 10.1371/journal.pone.0285265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Accepted: 04/19/2023] [Indexed: 06/02/2023] Open
Abstract
BACKGROUND Every 75 seconds, a child under five dies of malaria. Mainly children, aged between six months and five years, are at the highest risk for malaria. These children lost maternal immunity and did not yet developed specific immunity to the infection. Under the age of five, children bear the highest burden of malaria in Sub-Saharan Africa (SSA). Many individual and community level factors could contribute to malaria prevalence remaining high among under-five children in the region. Thus, this study aimed to assess the pooled prevalence of malaria among children aged 6-59 months and identify potential factors associated with malaria by using recent Malaria Indicator Surveys in 13 SSA countries. METHODS Data for this study were drawn from recent 13 Sub-Saharan African countries Malaria Indicator Surveys (MIS). A total weighted sample of 60,541 children aged 6-59 months was included. STATA version 14.2 was used to clean, code and analyze the data. Multilevel logistic regression was employed to identify factors associated with malaria. Adjusted odds ratio with 95% CI and a P value <0.05 was reported to indicate statistical association. Model fitness and comparison were done using Inter cluster correlation coefficient, Median odds ratio, proportional change in variance, and deviance. RESULTS The pooled prevalence of malaria among children aged 6-59 months was found to be 27.41% (95% CI: 17.94%-36.88%). It ranges from 5.04% in Senegal to 62.57% in Sierra Leone. Aged 36-47 months (AOR = 3.54, 95% CI 3.21-3.91), and 48-59 months (AOR = 4.32, 95% CI 3.91-4.77), mothers attended primary education (AOR = 0.78, 95% CI 0.73-0.84), richer (AOR = 0.35, 95% CI 0.32-0.39), and richest household (AOR = 0.16, 95% CI 0.14-0.19), number of three and more under-five children (AOR = 1.35, 95% CI 1.26-1.45), improved floor material (AOR = 0.65, 95% CI 0.57-0.73), improved wall material (AOR = 0.73, 95% CI 0.64-0.84), improved roof material (AOR = 0.70, 95% CI 0.51-0.93), insecticide-treated bed net (ITN) use (0.56, 95% CI 0.51-0.62), not anemic (AOR = 0.05, 95% CI 0.04-0.06), rural resident (AOR = 2.16, 95% CI 2.06-2.27), high community ITN use (AOR = 0.40, 95% CI 0.24-0.63) and high community poverty (AOR = 2.66, 95% CI 2.53-2.84) were strongly associated with malaria. CONCLUSIONS AND RECOMMENDATIONS Almost 3 out of 10 children were infected by malaria in 13 SSA countries. Malaria infection remains one of the main killers of children aged 6-59 months in the SSA. This study revealed that older under-five children living in large families with low incomes in rural areas are most vulnerable to malaria infection. Our results clearly indicate that ITN utilization and improved housing are promising means to effectively prevent malaria infection among children aged 6-59 months. It is therefore important to note that households with low wealth quintiles and rural residents should be prioritized in any mass distribution of ITNs. This has to be accompanied by education using mass media to enhance community awareness.
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Affiliation(s)
- Dagmawi Chilot
- Department of Human Physiology, University of Gondar, College of Medicine and Health Science, School of Medicine, Gondar, Ethiopia
| | - Annelies Mondelaers
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Adugnaw Zeleke Alem
- Department of Epidemiology & Biostatistics, Institute of Public Health, University of Gondar, College of Medicine and Health Science, Gondar, Ethiopia
| | - Mezgebu Selamsew Asres
- Department of Internal Medicine, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia
| | - Mulugeta Ayalew Yimer
- Department of Pediatrics and Child Health, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia
| | - Alemayehu Teklu Toni
- Department of Pediatrics and Child Health, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia
| | - Tadesse Awoke Ayele
- Department of Epidemiology & Biostatistics, Institute of Public Health, University of Gondar, College of Medicine and Health Science, Gondar, Ethiopia
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Musoke D, Atusingwize E, Namata C, Ndejjo R, Wanyenze RK, Kamya MR. Integrated malaria prevention in low- and middle-income countries: a systematic review. Malar J 2023; 22:79. [PMID: 36879237 PMCID: PMC9987134 DOI: 10.1186/s12936-023-04500-x] [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: 09/24/2022] [Accepted: 02/16/2023] [Indexed: 03/08/2023] Open
Abstract
BACKGROUND As many countries aim to eliminate malaria, use of comprehensive approaches targeting the mosquito vector and environment are needed. Integrated malaria prevention advocates the use of several malaria prevention measures holistically at households and in the community. The aim of this systematic review was to collate and summarize the impact of integrated malaria prevention in low- and middle-income countries on malaria burden. METHODS Literature on integrated malaria prevention, defined as the use of two or more malaria prevention methods holistically, was searched from 1st January 2001 to 31st July 2021. The primary outcome variables were malaria incidence and prevalence, while the secondary outcome measures were human biting and entomological inoculation rates, and mosquito mortality. RESULTS A total of 10,931 studies were identified by the search strategy. After screening, 57 articles were included in the review. Studies included cluster randomized controlled trials, longitudinal studies, programme evaluations, experimental hut/houses, and field trials. Various interventions were used, mainly combinations of two or three malaria prevention methods including insecticide-treated nets (ITNs), indoor residual spraying (IRS), topical repellents, insecticide sprays, microbial larvicides, and house improvements including screening, insecticide-treated wall hangings, and screening of eaves. The most common methods used in integrated malaria prevention were ITNs and IRS, followed by ITNs and topical repellents. There was reduced incidence and prevalence of malaria when multiple malaria prevention methods were used compared to single methods. Mosquito human biting and entomological inoculation rates were significantly reduced, and mosquito mortality increased in use of multiple methods compared to single interventions. However, a few studies showed mixed results or no benefits of using multiple methods to prevent malaria. CONCLUSION Use of multiple malaria prevention methods was effective in reducing malaria infection and mosquito density in comparison with single methods. Results from this systematic review can be used to inform future research, practice, policy and programming for malaria control in endemic countries.
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Affiliation(s)
- David Musoke
- Department of Disease Control and Environmental Health, School of Public Health, Makerere University College of Health Sciences, Kampala, Uganda.
| | - Edwinah Atusingwize
- Department of Disease Control and Environmental Health, School of Public Health, Makerere University College of Health Sciences, Kampala, Uganda
| | - Carol Namata
- Department of Disease Control and Environmental Health, School of Public Health, Makerere University College of Health Sciences, Kampala, Uganda
| | - Rawlance Ndejjo
- Department of Disease Control and Environmental Health, School of Public Health, Makerere University College of Health Sciences, Kampala, Uganda
| | - Rhoda K Wanyenze
- Department of Disease Control and Environmental Health, School of Public Health, Makerere University College of Health Sciences, Kampala, Uganda
| | - Moses R Kamya
- Department of Medicine, School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
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Echodu DC, Yeka A, Eganyu T, Odude W, Bukenya F, Amoah B, Wanzira H, Colborn K, Elliott RC, Powell SE, Kilama M, Mulebeke R, Nankabirwa J, Giorgi E, Roskosky M, Omoding O, Gonahasa S, Opigo J. Impact of population based indoor residual spraying with and without mass drug administration with dihydroartemisinin-piperaquine on malaria prevalence in a high transmission setting: a quasi-experimental controlled before-and-after trial in northeastern Uganda. BMC Infect Dis 2023; 23:72. [PMID: 36747133 PMCID: PMC9901833 DOI: 10.1186/s12879-023-07991-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 01/06/2023] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Declines in malaria burden in Uganda have slowed. Modelling predicts that indoor residual spraying (IRS) and mass drug administration (MDA), when co-timed, have synergistic impact. This study investigated additional protective impact of population-based MDA on malaria prevalence, if any, when added to IRS, as compared with IRS alone and with standard of care (SOC). METHODS The 32-month quasi-experimental controlled before-and-after trial enrolled an open cohort of residents (46,765 individuals, 1st enumeration and 52,133, 4th enumeration) of Katakwi District in northeastern Uganda. Consented participants were assigned to three arms based on residential subcounty at study start: MDA+IRS, IRS, SOC. IRS with pirimiphos methyl and MDA with dihydroartemisinin- piperaquine were delivered in 4 co-timed campaign-style rounds 8 months apart. The primary endpoint was population prevalence of malaria, estimated by 6 cross-sectional surveys, starting at baseline and preceding each subsequent round. RESULTS Comparing malaria prevalence in MDA+IRS and IRS only arms over all 6 surveys (intention-to-treat analysis), roughly every 6 months post-interventions, a geostatistical model found a significant additional 15.5% (95% confidence interval (CI): [13.7%, 17.5%], Z = 9.6, p = 5e-20) decrease in the adjusted odds ratio (aOR) due to MDA for all ages, a 13.3% reduction in under 5's (95% CI: [10.5%, 16.8%], Z = 4.02, p = 5e-5), and a 10.1% reduction in children 5-15 (95% CI: [8.5%, 11.8%], Z = 4.7, p = 2e-5). All ages residents of the MDA + IRS arm enjoyed an overall 80.1% reduction (95% CI: [80.0%, 83.0%], p = 0.0001) in odds of qPCR confirmed malaria compared with SOC residents. Secondary difference-in-difference analyses comparing surveys at different timepoints to baseline showed aOR (MDA + IRS vs IRS) of qPCR positivity between 0.28 and 0.66 (p < 0.001). Of three serious adverse events, one (nonfatal) was considered related to study medications. Limitations include the initial non-random assignment of study arms, the single large cluster per arm, and the lack of an MDA-only arm, considered to violate equipoise. CONCLUSIONS Despite being assessed at long time points 5-7 months post-round, MDA plus IRS provided significant additional protection from malaria infection over IRS alone. Randomized trials of MDA in large areas undergoing IRS recommended as well as cohort studies of impact on incidence. TRIAL REGISTRATION This trial was retrospectively registered 11/07/2018 with the Pan African Clinical Trials Registry (PACTR201807166695568).
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Affiliation(s)
| | - Adoke Yeka
- grid.11194.3c0000 0004 0620 0548Makerere University College of Health Sciences, School of Public Health, P.O. Box 7072, Kampala, Uganda
| | - Thomas Eganyu
- Pilgrim Africa, Plot 8 Engwau Road, PO Box 577, Soroti, Uganda
| | - Wycliff Odude
- Pilgrim Africa, Plot 8 Engwau Road, PO Box 577, Soroti, Uganda
| | - Fred Bukenya
- Pilgrim Africa, Plot 8 Engwau Road, PO Box 577, Soroti, Uganda
| | - Benjamin Amoah
- grid.7445.20000 0001 2113 8111School of Public Health, Imperial College London, Sir Alexander Fleming Building, South Kensington Campus, London, SW7 2AZ UK
| | | | - Kathryn Colborn
- grid.430503.10000 0001 0703 675XUniversity of Colorado Anschutz Medical Campus, 12631 East 17th Avenue, Aurora, CO 80045 USA
| | - Richard C. Elliott
- Pilgrim Africa, 8001 14th Avenue NE, Suite A, Seattle, WA 98115 USA ,grid.184764.80000 0001 0670 228XMicron School of Materials Science and Engineering, Boise State University, Engineering Building, Suite 338, Boise, ID 83725 USA
| | | | - Maxwell Kilama
- Pilgrim Africa, Plot 8 Engwau Road, PO Box 577, Soroti, Uganda
| | - Ronald Mulebeke
- grid.11194.3c0000 0004 0620 0548Makerere University College of Health Sciences, School of Public Health, P.O. Box 7072, Kampala, Uganda
| | - Joaniter Nankabirwa
- grid.463352.50000 0004 8340 3103Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Emanuele Giorgi
- grid.9835.70000 0000 8190 6402Lancaster University Medical School, Centre for Health Informatics, Computing and Statistics, Lancaster, UK
| | - Mellisa Roskosky
- Pilgrim Africa, 8001 14th Avenue NE, Suite A, Seattle, WA 98115 USA ,grid.21107.350000 0001 2171 9311Johns Hopkins Bloomberg School of Public Health, Baltimore, MD USA
| | - Osborn Omoding
- Pilgrim Africa, Plot 8 Engwau Road, PO Box 577, Soroti, Uganda
| | - Samuel Gonahasa
- grid.463352.50000 0004 8340 3103Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Jimmy Opigo
- grid.415705.2National Malaria Control Division, Ministry of Health Uganda, Kampala, Uganda
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10
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Abong’o B, Gimnig JE, Omoke D, Ochomo E, Walker ED. Screening eaves of houses reduces indoor mosquito density in rural, western Kenya. Malar J 2022; 21:377. [PMID: 36494664 PMCID: PMC9733111 DOI: 10.1186/s12936-022-04397-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 11/22/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Despite the scale-up of insecticide-treated nets and indoor residual spraying, the bulk of malaria transmission in western Kenya still occurs indoors, late at night. House improvement is a potential long-term solution to further reduce malaria transmission in the region. METHODS The impact of eave screening on mosquito densities was evaluated in two rural villages in western Kenya. One-hundred-and-twenty pairs of structurally similar, neighbouring houses were used in the study. In each pair, one house was randomly selected to receive eave screening at the beginning of the study while the other remained unscreened until the end of the sampling period. Mosquito sampling was performed monthly by motorized aspiration method for 4 months. The collected mosquitoes were analysed for species identification. RESULTS Compared to unscreened houses, significantly fewer female Anopheles funestus (RR = 0.40, 95% CI 0.29-0.55), Anopheles gambiae Complex (RR = 0.46, 95% CI 0.34-0.62) and Culex species (RR = 0.53, 95% CI 0.45-0.61) were collected in screened houses. No significant differences in the densities of the mosquitoes were detected in outdoor collections. Significantly fewer Anopheles funestus were collected indoors from houses with painted walls (RR = 0.05, 95% CI 0.01-0.38) while cooking in the house was associated with significantly lower numbers of Anopheles gambiae Complex indoors (RR = 0.60, 95% CI 0.45-0.79). Nearly all house owners (99.6%) wanted their houses permanently screened, including 97.7% that indicated a willingness to use their own resources. However, 99.2% required training on house screening. The cost of screening a single house was estimated at KES6,162.38 (US$61.62). CONCLUSION Simple house modification by eave screening has the potential to reduce the indoor occurrence of both Anopheles and Culex mosquito species. Community acceptance was very high although education and mobilization may be needed for community uptake of house modification for vector control. Intersectoral collaboration and favourable government policies on housing are important links towards the adoption of house improvements for malaria control.
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Affiliation(s)
- Bernard Abong’o
- grid.33058.3d0000 0001 0155 5938Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - John E. Gimnig
- grid.416738.f0000 0001 2163 0069Centers for Disease Control and Prevention, Division of Parasitic Diseases, Atlanta, GA 30341 USA
| | - Diana Omoke
- grid.33058.3d0000 0001 0155 5938Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Eric Ochomo
- grid.33058.3d0000 0001 0155 5938Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Edward D. Walker
- grid.17088.360000 0001 2150 1785Michigan State University, 6169 Biomedical Physical Sciences Building, East Lansing, MI 48824 USA
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11
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Zhou Y, Zhang WX, Tembo E, Xie MZ, Zhang SS, Wang XR, Wei TT, Feng X, Zhang YL, Du J, Liu YQ, Zhang X, Cui F, Lu QB. Effectiveness of indoor residual spraying on malaria control: a systematic review and meta-analysis. Infect Dis Poverty 2022; 11:83. [PMID: 35870946 PMCID: PMC9308352 DOI: 10.1186/s40249-022-01005-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 06/30/2022] [Indexed: 11/18/2022] Open
Abstract
Background Indoor residual spraying (IRS) is one of the key interventions recommended by World Health Organization in preventing malaria infection. We aimed to conduct a systematic review and meta-analysis of global studies about the impact of IRS on malaria control. Method We searched PubMed, Web of Science, Embase, and Scopus for relevant studies published from database establishment to 31 December 2021. Random-effects models were used to perform meta-analysis and subgroup analysis to pool the odds ratio (OR) and 95% confidence interval (CI). Meta-regression was used to investigate potential factors of heterogeneity across studies. Results Thirty-eight articles including 81 reports and 1,174,970 individuals were included in the meta-analysis. IRS was associated with lower rates of malaria infection (OR = 0.35, 95% CI: 0.27–0.44). The significantly higher effectiveness was observed in IRS coverage ≥ 80% than in IRS coverage < 80%. Pyrethroids was identified to show the greatest performance in malaria control. In addition, higher effectiveness was associated with a lower gross domestic product
as well as a higher coverage of IRS and bed net utilization. Conclusions IRS could induce a positive effect on malaria infection globally. The high IRS coverage and the use of pyrethroids are key measures to reduce malaria infection. More efforts should focus on increasing IRS coverage, developing more effective new insecticides against malaria, and using multiple interventions comprehensively to achieve malaria control goals. Supplementary Information The online version contains supplementary material available at 10.1186/s40249-022-01005-8.
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12
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Asale A, Kassie M, Abro Z, Enchalew B, Belay A, Sangoro PO, Tchouassi DP, Mutero CM. The combined impact of LLINs, house screening, and pull-push technology for improved malaria control and livelihoods in rural Ethiopia: study protocol for household randomised controlled trial. BMC Public Health 2022; 22:930. [PMID: 35538444 PMCID: PMC9088127 DOI: 10.1186/s12889-022-12919-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 03/04/2022] [Indexed: 11/23/2022] Open
Abstract
Background The combined application of long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) are commonly used malaria interventions that target indoor Anopheles vectors. Recent studies on the effects of house screening (HS) and LLINs have demonstrated a reduction in indoor vector densities and malaria when the interventions are combined. In addition, complementary interventions are needed to curb co-occurring pest populations which pose menace to agricultural crop productivity and food security. However, interventions that impact malaria mainly centre on public health strategies, overlooking subtle but important component of agricultural measures. Addressing the coexisting risks of malaria and crop pests could contribute to improved livelihood of communities. Methods A four-armed household, cluster-randomized, controlled study will be conducted to assess the combined impact of HS, LLINs and push-pull agricultural technology (PPT) against clinical malaria in children in Ethiopia. The unit of randomization will be the household, which includes a house and its occupants. A total of 838 households will be enrolled in this study. In this trial 246 households will receive LLINs and HS, 250 will receive LLINs, HS and PPT, 175 households will receive LLINs and PPT. The remaining 167 houses which receive LLINs only will be used as control. One child aged ≤14 years will be enrolled per household in each treatment and followed for clinical malaria using active case detection to estimate malaria incidence for two malaria transmission seasons. Discussion Episodes of clinical malaria, density of indoor biting malaria vectors, sporozoite infection rate, improved crop infestation rate, crop yield gain, livestock productivity and cost effectiveness analysis will be the end points of this study. Socio-economic, social demographic, cost-effectiveness analysis will be conducted using qualitative and participatory methods to explore the acceptability of HS and PPT. Documenting the combined impact of LLINs, HS and PPT on the prevalence of clinical malaria and crop pest damage will be the first of its kind. Trial registration Pan African Clinical Trials Registry, PACTR202006878245287. 24/06/2020. https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=11101. Supplementary Information The online version contains supplementary material available at 10.1186/s12889-022-12919-1.
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Affiliation(s)
- Abebe Asale
- International Centre of Insect Physiology and Ecology, Addis Ababa, Ethiopia.
| | - Menale Kassie
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Zewdu Abro
- International Centre of Insect Physiology and Ecology, Addis Ababa, Ethiopia
| | - Bayu Enchalew
- International Centre of Insect Physiology and Ecology, Addis Ababa, Ethiopia
| | - Aklilu Belay
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya.,University of Pretoria Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
| | - Peter O Sangoro
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - David P Tchouassi
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Clifford M Mutero
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya.,University of Pretoria Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
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13
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Nguyen TT, Nguyen XX, Wilson-Barthes M, Sawada I, Muela J, Hausmann-Muela S, Pham TV, Van Nguyen H, Van Nguyen V, Tran DT, Gryseels C, D'Alessandro U, Grietens KP, Erhart A. Why using bed nets is a challenge among minority populations in Central Vietnam. Malar J 2022; 21:87. [PMID: 35292018 PMCID: PMC8922825 DOI: 10.1186/s12936-022-04114-9] [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: 08/10/2021] [Accepted: 03/02/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Despite freely distributed insecticide-treated nets (ITNs) and health information campaigns to increase their use among populations at risk, malaria transmission persists in forested areas in Vietnam, especially among ethnic minority communities. A mixed-methods study was conducted in four villages of Ca Dong and M'nong ethnicity in Central Vietnam between 2009 and 2011 to assess factors limiting the uptake of ITNs. METHODS The mixed-methods research design consisted of a qualitative study to explore the context and barriers to ITN use, and a cross-sectional household survey (n = 141) to quantify factors for limited and appropriate net use. RESULTS The Ca Dong and M'nong's livelihood was dependent on swidden farming in the forest. Poverty-related factors, including the lack of beds, blankets, the practice of sleeping around the kitchen fire and deteriorated ITNs due to open housing structures, were reasons for alternative and non-use of ITNs. When household members stayed overnight in plot huts at fields, ITNs were even more unavailable and easily deteriorated. 72.5% of households reported having received one net for every two persons, and 82.2% of participants reported to have used ITNs the night before the survey. However, only 18.4% of participants were estimated to be effectively protected by ITNs after accounting for the availability of torn ITNs and the way ITNs were used, for example as blankets, at both village and fields. Multi-variable logistic regression showed the effect of four significant factors for appropriate ITN use: i) being female (AOR = 8.08; p = 0.009); ii) aware of mosquito bites as the sole cause of malaria (AOR = 7.43; p = 0.008); iii) not sleeping around the kitchen fire (AOR = 24.57; p = 0.001); and iv) having sufficient number of ITNs in the household (AOR = 21.69; p = 0.001). CONCLUSION This study showed how social factors rooted in poverty and swidden agriculture limited the effective use of ITNs, despite high coverage, among ethnic minority populations in Central Vietnam. An in-depth understanding of the local context is essential to develop specific indicators for measuring ITN use.
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Affiliation(s)
- Thuan Thi Nguyen
- Socio-Ecological Health Research Unit, Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium. .,National Institute of Malariology, Parasitology and Entomology, Hanoi, Vietnam.
| | - Xa Xuan Nguyen
- National Institute of Malariology, Parasitology and Entomology, Hanoi, Vietnam
| | - Marta Wilson-Barthes
- International Health Institute, Brown University School of Public Health, Providence, USA
| | - Ikumi Sawada
- Department of Clinical Tropical Medicine, Institute of Tropical Medicine, Graduate School of Biomedical Science, Nagasaki University, Nagasaki, Japan
| | - Joan Muela
- University Ramon I Virgili, Tarragona, Spain.,Partners for Applied Social Sciences, PASS International, Tessenderlo, Belgium
| | | | - Thanh Vinh Pham
- National Institute of Malariology, Parasitology and Entomology, Hanoi, Vietnam
| | - Hong Van Nguyen
- National Institute of Malariology, Parasitology and Entomology, Hanoi, Vietnam
| | | | - Duong Thanh Tran
- National Institute of Malariology, Parasitology and Entomology, Hanoi, Vietnam
| | - Charlotte Gryseels
- Socio-Ecological Health Research Unit, Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
| | - Umberto D'Alessandro
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Koen Peeters Grietens
- Socio-Ecological Health Research Unit, Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium.,Partners for Applied Social Sciences, PASS International, Tessenderlo, Belgium.,School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
| | - Annette Erhart
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
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14
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Magnitude of visceral leishmaniasis and HIV coinfection and association with social determinants of health in the Northeast region of Brazil: a retrospective, spatiotemporal model (2010-2018). Parasitol Res 2022; 121:1021-1031. [PMID: 35142927 DOI: 10.1007/s00436-022-07450-6] [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: 10/25/2021] [Accepted: 01/26/2022] [Indexed: 10/19/2022]
Abstract
The Northeast region of Brazil (NRB) includes the states with the highest prevalence of visceral leishmaniasis (VL), as well as those with significant increases in HIV cases. This study aims to analyze the spatiotemporal patterns of VL-HIV coinfection and its association with the social determinants of health (SDH) in the NRB. Time trend analysis and Bayesian spatial statistical inferences, Moran's autocorrelation, and retrospective space-time scanning were performed. Spatial regression modelling was used to build an explanatory model for the occurrence of VL-HIV coinfection within NRB. A total of 1550 cases of VL-HIV coinfection were confirmed. We observed a higher prevalence among males (1232; 83%), individuals aged from 20 to 59 years (850; 54.8%), non-white skin color (1,422; 91.7%), and with low education (550; 35.48%). NRB showed an increasing and significant trend in the detection rate of coinfection (APC, 5.3; 95% CI, 1.4 to 9.4). The states of Maranhão and Piauí comprised the high-risk cluster. The SDH that most correlated with the occurrence of coinfection were poor housing, low income, and low education. VL-HIV is dispersed in the NRB but chiefly affects states with greater social vulnerability. Taken together, these findings reinforce the necessity to implement surveillance strategies that will contribute to the reduction of cases in these populations.
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15
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Malaria prevention interventions beyond long-lasting insecticidal nets and indoor residual spraying in low- and middle-income countries: a scoping review. Malar J 2022; 21:31. [PMID: 35109848 PMCID: PMC8812253 DOI: 10.1186/s12936-022-04052-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 01/17/2022] [Indexed: 11/13/2022] Open
Abstract
Background Significant progress in malaria prevention during the past two decades has prompted increasing global dialogue on malaria elimination. Recent reviews on malaria strategies have focused mainly on long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS), with little emphasis on other prevention methods. This article is a scoping review of literature on malaria prevention methods beyond LLINs and IRS in low- and middle-income countries (LMICs). Methods This scoping review found articles published between from 1994 to 2020. Studies were obtained from a search of the PubMed, the Cochrane Library and Social Science abstracts. Grey literature and manual search of secondary references was also done. The search strategy included all study designs but limited only to English. Three independent reviewers performed the selection and characterization of articles, and the data collected were synthesized qualitatively. Results A total of 10,112 studies were identified among which 31 met the inclusion criteria. The results were grouped by the 3 emerging themes of: housing design; mosquito repellents; and integrated vector control. Housing design strategies included closing eves, screening of houses including windows, doors and ceilings, while mosquito repellents were mainly spatial repellents, use of repellent plants, and use of plant-based oils. Integrated vector control included larvae source management. Evidence consistently shows that improving housing design reduced mosquito entry and malaria prevalence. Spatial repellents also showed promising results in field experiments, while evidence on repellent plants is limited and still emerging. Recent literature shows that IVM has been largely ignored in recent years in many LMICs. Some malaria prevention methods such as spatial repellents and IVM are shown to have the potential to target both indoor and outdoor transmission of malaria, which are both important aspects to consider to achieve malaria elimination in LMICs. Conclusion The scoping review shows that other malaria prevention strategies beyond LLINs and IRS have increasingly become important in LMICs. These methods have a significant role in contributing to malaria elimination in endemic countries if they are adequately promoted alongside other conventional approaches. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04052-6.
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16
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Musiime AK, Krezanoski PJ, Smith DL, Kilama M, Conrad MD, Otto G, Kyagamba P, Asiimwe J, Rek J, Nankabirwa JI, Arinaitwe E, Akol AM, Kamya MR, Staedke SG, Drakeley C, Bousema T, Lindsay SW, Dorsey G, Tusting LS. House design and risk of malaria, acute respiratory infection and gastrointestinal illness in Uganda: A cohort study. PLOS GLOBAL PUBLIC HEALTH 2022; 2:e0000063. [PMID: 36962263 PMCID: PMC10022195 DOI: 10.1371/journal.pgph.0000063] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 11/15/2021] [Indexed: 11/18/2022]
Abstract
House construction is rapidly modernizing across Africa but the potential benefits for human health are poorly understood. We hypothesised that improvements to housing would be associated with reductions in malaria, acute respiratory infection (ARI) and gastrointestinal illness in an area of low malaria endemicity in Uganda. Data were analysed from a cohort study of male and female child and adult residents (n = 531) of 80 randomly-selected households in Nagongera sub-county, followed for 24 months (October 4, 2017 to October 31, 2019). Houses were classified as modern (brick walls, metal roof and closed eaves) or traditional (all other homes). Light trap collections of mosquitoes were done every two weeks in all sleeping rooms. Every four weeks, we measured malaria infection (using microscopy and qPCR to detect malaria parasites), incidence of malaria, ARI and gastrointestinal illness. We collected 15,780 adult female Anopheles over 7,631 nights. We collected 13,277 blood samples of which 10.2% (1,347) were positive for malaria parasites. Over 958 person years we diagnosed 38 episodes of uncomplicated malaria (incidence 0.04 episodes per person-year at risk), 2,553 episodes of ARI (incidence 2.7 episodes per person-year) and 387 episodes of gastrointestinal illness (incidence 0.4 episodes per person-year). Modern houses were associated with a 53% lower human biting rate compared to traditional houses (adjusted incidence rate ratio [aIRR] 0.47, 95% confidence interval [CI] 0.32-0.67, p<0.001) and a 24% lower incidence of gastrointestinal illness (aIRR 0.76, 95% CI 0.59-0.98, p = 0.04) but no changes in malaria prevalence, malaria incidence nor ARI incidence. House improvements may reduce mosquito-biting rates and gastrointestinal illness among children and adults. For the health sector to leverage Africa's housing modernization, research is urgently needed to identify the healthiest house designs and to assess their effectiveness across a range of epidemiological settings in sub-Saharan Africa.
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Affiliation(s)
- Alex K Musiime
- Infectious Diseases Research Collaboration, Kampala, Uganda
- Department of Zoology, Entomology and Fisheries Sciences, College of Natural Sciences, Makerere University, Kampala, Uganda
| | - Paul J Krezanoski
- Department of Medicine, San Francisco General Hospital, University of California, San Francisco, United States of America
| | - David L Smith
- Department of Health Metrics Sciences, University of Washington, Seattle, United States of America
| | - Maxwell Kilama
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Melissa D Conrad
- Department of Medicine, San Francisco General Hospital, University of California, San Francisco, United States of America
| | - Geoffrey Otto
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | | | - John Rek
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Joaniter I Nankabirwa
- Infectious Diseases Research Collaboration, Kampala, Uganda
- Department of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | | | - Anne M Akol
- Department of Zoology, Entomology and Fisheries Sciences, College of Natural Sciences, Makerere University, Kampala, Uganda
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda
- Department of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Sarah G Staedke
- Faculty of Infectious and Tropical Diseases, Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Chris Drakeley
- Faculty of Infectious and Tropical Diseases, Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Steve W Lindsay
- Department of Biosciences, Durham University, Durham, United Kingdom
| | - Grant Dorsey
- Department of Medicine, San Francisco General Hospital, University of California, San Francisco, United States of America
| | - Lucy S Tusting
- Faculty of Infectious and Tropical Diseases, Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Centre on Climate Change and Planetary Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
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17
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Yaro JB, Tiono AB, Sanou A, Toe HK, Bradley J, Ouedraogo A, Ouedraogo ZA, Guelbeogo MW, Agboraw E, Worrall E, Sagnon N'F, Lindsay SW, Wilson AL. Risk factors associated with house entry of malaria vectors in an area of Burkina Faso with high, persistent malaria transmission and high insecticide resistance. Malar J 2021; 20:397. [PMID: 34629053 PMCID: PMC8504047 DOI: 10.1186/s12936-021-03926-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 09/26/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In rural Burkina Faso, the primary malaria vector Anopheles gambiae sensu lato (s.l.) primarily feeds indoors at night. Identification of factors which influence mosquito house entry could lead to development of novel malaria vector control interventions. A study was therefore carried out to identify risk factors associated with house entry of An. gambiae s.l. in south-west Burkina Faso, an area of high insecticide resistance. METHODS Mosquitoes were sampled monthly during the malaria transmission season using CDC light traps in 252 houses from 10 villages, each house sleeping at least one child aged five to 15 years old. Potential risk factors for house entry of An. gambiae s.l. were measured, including socio-economic status, caregiver's education and occupation, number of people sleeping in the same part of the house as the child, use of anti-mosquito measures, house construction and fittings, proximity of anopheline aquatic habitats and presence of animals near the house. Mosquito counts were compared using a generalized linear mixed-effect model with negative binomial and log link function, adjusting for repeated collections. RESULTS 20,929 mosquitoes were caught, of which 16,270 (77.7%) were An. gambiae s.l. Of the 6691 An. gambiae s.l. identified to species, 4101 (61.3%) were An. gambiae sensu stricto and 2590 (38.7%) Anopheles coluzzii. Having a metal-roof on the child's sleeping space (IRR = 0.55, 95% CI 0.32-0.95, p = 0.03) was associated with fewer malaria vectors inside the home. CONCLUSION This study demonstrated that the rate of An. gambiae s.l. was 45% lower in sleeping spaces with a metal roof, compared to those with thatch roofs. Improvements in house construction, including installation of metal roofs, should be considered in endemic areas of Africa to reduce the burden of malaria.
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Affiliation(s)
- Jean Baptiste Yaro
- Centre National de Recherche Et de Formation Sur Le Paludisme, Ouagadougou, Burkina Faso.,Department of Biosciences, Durham University, Durham, UK
| | - Alfred B Tiono
- Centre National de Recherche Et de Formation Sur Le Paludisme, Ouagadougou, Burkina Faso
| | - Antoine Sanou
- Centre National de Recherche Et de Formation Sur Le Paludisme, Ouagadougou, Burkina Faso
| | - Hyacinthe K Toe
- Centre National de Recherche Et de Formation Sur Le Paludisme, Ouagadougou, Burkina Faso
| | - John Bradley
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| | - Alphonse Ouedraogo
- Centre National de Recherche Et de Formation Sur Le Paludisme, Ouagadougou, Burkina Faso
| | - Z Amidou Ouedraogo
- Centre National de Recherche Et de Formation Sur Le Paludisme, Ouagadougou, Burkina Faso
| | - Moussa W Guelbeogo
- Centre National de Recherche Et de Formation Sur Le Paludisme, Ouagadougou, Burkina Faso
| | - Efundem Agboraw
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Eve Worrall
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - N 'Fale Sagnon
- Centre National de Recherche Et de Formation Sur Le Paludisme, Ouagadougou, Burkina Faso
| | | | - Anne L Wilson
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK.
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Anaele BI, Varshney K, Ugwu FSO, Frasso R. The efficacy of insecticide-treated window screens and eaves against Anopheles mosquitoes: a scoping review. Malar J 2021; 20:388. [PMID: 34587958 PMCID: PMC8480128 DOI: 10.1186/s12936-021-03920-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 09/17/2021] [Indexed: 11/27/2022] Open
Abstract
Background Female mosquitoes serve as vectors for a host of illnesses, including malaria, spread by the Plasmodium parasite. Despite monumental strides to reduce this disease burden through tools such as bed nets, the rate of these gains is slowing. Ongoing disruptions related to the COVID-19 pandemic may also negatively impact gains. The following scoping review was conducted to examine novel means of reversing this trend by exploring the efficacy of insecticide-treated window screens or eaves to reduce Anopheles mosquito bites, mosquito house entry, and density. Methods Two reviewers independently searched PubMed, Scopus, and ProQuest databases on 10 July, 2020 for peer-reviewed studies using insecticide-treated screens or eaves in malaria-endemic countries. These articles were published in English between the years 2000–2020. Upon collection, the reports were stratified into categories of biting incidence and protective efficacy, mosquito entry and density, and mosquito mortality. Results Thirteen out of 2180 articles were included in the final review. Eaves treated with beta-cyfluthrin, transfluthrin or bendiocarb insecticides were found to produce vast drops in blood-feeding, biting or mosquito prevalence. Transfluthrin-treated eaves were reported to have greater efficacy at reducing mosquito biting: Rates dropped by 100% both indoors and outdoors under eave ribbon treatments of 0.2% transfluthrin (95% CI 0.00–0.00; p < 0.001). Additionally, co-treating window screens and eaves with polyacrylate-binding agents and with pirimiphos-methyl has been shown to retain insecticidal potency after several washes, with a mosquito mortality rate of 94% after 20 washes (95% CI 0.74–0.98; p < 0.001). Conclusions The results from this scoping review suggest that there is value in implementing treated eave tubes or window screens. More data are needed to study the longevity of screens and household attitudes toward these interventions.
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Affiliation(s)
- Beverly I Anaele
- College of Population Health, Thomas Jefferson University, Philadelphia, PA, USA.
| | - Karan Varshney
- College of Population Health, Thomas Jefferson University, Philadelphia, PA, USA.,School of Medicine, Deakin University, Geelong, VIC, Australia
| | - Francis S O Ugwu
- South East Zonal Biotechnology Centre and Department of Zoology and Environmental Biology, University of Nigeria, Nsukka, Nigeria
| | - Rosemary Frasso
- College of Population Health, Thomas Jefferson University, Philadelphia, PA, USA
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19
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Oliveira TMP, Laporta GZ, Bergo ES, Chaves LSM, Antunes JLF, Bickersmith SA, Conn JE, Massad E, Sallum MAM. Vector role and human biting activity of Anophelinae mosquitoes in different landscapes in the Brazilian Amazon. Parasit Vectors 2021; 14:236. [PMID: 33957959 PMCID: PMC8101188 DOI: 10.1186/s13071-021-04725-2] [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: 12/14/2020] [Accepted: 04/16/2021] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Environmental disturbance, deforestation and socioeconomic factors all affect malaria incidence in tropical and subtropical endemic areas. Deforestation is the major driver of habitat loss and fragmentation, which frequently leads to shifts in the composition, abundance and spatial distribution of vector species. The goals of the present study were to: (i) identify anophelines found naturally infected with Plasmodium; (ii) measure the effects of landscape on the number of Nyssorhynchus darlingi, presence of Plasmodium-infected Anophelinae, human biting rate (HBR) and malaria cases; and (iii) determine the frequency and peak biting time of Plasmodium-infected mosquitoes and Ny. darlingi. METHODS Anopheline mosquitoes were collected in peridomestic and forest edge habitats in seven municipalities in four Amazon Brazilian states. Females were identified to species and tested for Plasmodium by real-time PCR. Negative binomial regression was used to measure any association between deforestation and number of Ny. darlingi, number of Plasmodium-infected Anophelinae, HBR and malaria. Peak biting time of Ny. darlingi and Plasmodium-infected Anophelinae were determined in the 12-h collections. Binomial logistic regression measured the association between presence of Plasmodium-infected Anophelinae and landscape metrics and malaria cases. RESULTS Ninety-one females of Ny. darlingi, Ny. rangeli, Ny. benarrochi B and Ny. konderi B were found to be infected with Plasmodium. Analysis showed that the number of malaria cases and the number of Plasmodium-infected Anophelinae were more prevalent in sites with higher edge density and intermediate forest cover (30-70%). The distance of the drainage network to a dwelling was inversely correlated to malaria risk. The peak biting time of Plasmodium-infected Anophelinae was 00:00-03:00 h. The presence of Plasmodium-infected mosquitoes was higher in landscapes with > 13 malaria cases. CONCLUSIONS Nyssorhynchus darlingi, Ny. rangeli, Ny. benarrochi B and Ny. konderi B can be involved in malaria transmission in rural settlements. The highest fraction of Plasmodium-infected Anophelinae was caught from midnight to 03:00 h. In some Amazonian localities, the highest exposure to infectious bites occurs when residents are sleeping, but transmission can occur throughout the night. Forest fragmentation favors increases in both malaria and the occurrence of Plasmodium-infected mosquitoes in peridomestic habitat. The use of insecticide-impregnated mosquito nets can decrease human exposure to infectious Anophelinae and malaria transmission.
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Affiliation(s)
- Tatiane M P Oliveira
- Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, Av. Dr. Arnaldo, 715, Cerqueira César, São Paulo, SP, 01246-904, Brazil.
| | - Gabriel Z Laporta
- Setor de Pós-Graduação, Pesquisa e Inovação, Centro Universitário Saúde ABC (FMABC), Fundação ABC, Santo André, SP, Brazil
| | - Eduardo S Bergo
- Superintendencia de Controle de Endemias, Secretaria de Estado da Saúde, Araraquara, SP, Brazil
| | - Leonardo Suveges Moreira Chaves
- Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, Av. Dr. Arnaldo, 715, Cerqueira César, São Paulo, SP, 01246-904, Brazil
| | - José Leopoldo F Antunes
- Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, Av. Dr. Arnaldo, 715, Cerqueira César, São Paulo, SP, 01246-904, Brazil
| | | | - Jan E Conn
- Wadsworth Center, New York State Department of Health, Albany, NY, USA
- Department of Biomedical Sciences, School of Public Health, State University of New York, Albany, NY, USA
| | - Eduardo Massad
- Escola de Matemática Aplicada, Fundação Getúlio Vargas, Rio de Janeiro, RJ, Brazil
| | - Maria Anice Mureb Sallum
- Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, Av. Dr. Arnaldo, 715, Cerqueira César, São Paulo, SP, 01246-904, Brazil
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20
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Zehner N, Adrama H, Kakuru A, Andra T, Kajubi R, Conrad M, Nankya F, Clark TD, Kamya M, Rodriguez-Barraquer I, Dorsey G, Jagannathan P. Age-related Changes in Malaria Clinical Phenotypes During Infancy are Modified by Sickle Cell Trait. Clin Infect Dis 2021; 73:1887-1895. [PMID: 33738485 PMCID: PMC8599196 DOI: 10.1093/cid/ciab245] [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: 11/12/2020] [Indexed: 12/02/2022] Open
Abstract
Background Infants are protected against Plasmodium falciparum malaria. Mechanisms that drive this protection remain unclear due to a poor understanding of malaria clinical phenotypes during infancy. Methods We enrolled a birth cohort of 678 infants in Busia, Uganda, an area of high malaria transmission. We followed infants through 12 months of age and quantified protection against parasitemia and clinical disease. Results Symptomatic malaria incidence increased from 1.2 to 2.6 episodes per person-year between 0 and <6 months and between 6 and 12 months of age, while the monthly probability of asymptomatic parasitemia given infection decreased from 32% to 21%. Sickle cell trait (HbAS) was protective against symptomatic malaria (incidence rate ratio = 0.57 comparing HbAS vs hemoglobin AA (HbAA); 95% confidence interval, 0.44–0.74; P < .001), but age modified this relationship (Pint = <0.001), with nonlinear protection that waned between 0 and 9 months of age before increasing. Increasing age was associated with higher parasite densities at the time of infection and, in infants with HbAS, a reduced ability to tolerate high parasite densities without fever. Conclusions Age-dependent changes in HbAS protective efficacy in infancy were accompanied by differential loss of antiparasite and antidisease protection among HbAS and HbAA infants. This provides a framework for investigating the mechanisms that underlie infant protection against malaria. Clinical Trials Registration NCT02793622.
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Affiliation(s)
| | - Harriet Adrama
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Abel Kakuru
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Teddy Andra
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Richard Kajubi
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Melissa Conrad
- Department of Medicine, University of California, San Francisco, USA
| | | | - Tamara D Clark
- Department of Medicine, University of California, San Francisco, USA
| | - Moses 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, USA
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21
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Jones RT, Ant TH, Cameron MM, Logan JG. Novel control strategies for mosquito-borne diseases. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190802. [PMID: 33357056 PMCID: PMC7776938 DOI: 10.1098/rstb.2019.0802] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/11/2020] [Indexed: 12/23/2022] Open
Abstract
Mosquito-borne diseases are an increasing global health challenge, threatening over 40% of the world's population. Despite major advances in malaria control since 2000, recent progress has stalled. Additionally, the risk of Aedes-borne arboviruses is rapidly growing, with the unprecedented spread of dengue and chikungunya viruses, outbreaks of yellow fever and the 2015 epidemic of Zika virus in Latin America. To counteract this growing problem, diverse and innovative mosquito control technologies are currently under development. Conceptually, these span an impressive spectrum of approaches, from invasive transgene cassettes with the potential to crash mosquito populations or reduce the vectorial capacity of a population, to low-cost alterations in housing design that restrict mosquito entry. This themed issue will present articles providing insight into the breadth of mosquito control research, while demonstrating the requirement for an interdisciplinary approach. The issue will highlight mosquito control technologies at varying stages of development and includes both opinion pieces and research articles with laboratory and field-based data on control strategy development. This article is part of the theme issue 'Novel control strategies for mosquito-borne diseases'.
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Affiliation(s)
- Robert T. Jones
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, Bloomsbury, London WC1E 7HT, UK
| | - Thomas H. Ant
- Centre for Virus Research, Bearsden Road, Bearsden, Glasgow G61 1QH, UK
| | - Mary M. Cameron
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, Bloomsbury, London WC1E 7HT, UK
| | - James G. Logan
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, Bloomsbury, London WC1E 7HT, UK
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22
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Soma DD, Zogo B, Taconet P, Somé A, Coulibaly S, Baba-Moussa L, Ouédraogo GA, Koffi A, Pennetier C, Dabiré KR, Moiroux N. Quantifying and characterizing hourly human exposure to malaria vectors bites to address residual malaria transmission during dry and rainy seasons in rural Southwest Burkina Faso. BMC Public Health 2021; 21:251. [PMID: 33516197 PMCID: PMC7847557 DOI: 10.1186/s12889-021-10304-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 01/21/2021] [Indexed: 11/17/2022] Open
Abstract
Background To sustain the efficacy of malaria vector control, the World Health Organization (WHO) recommends the combination of effective tools. Before designing and implementing additional strategies in any setting, it is critical to monitor or predict when and where transmission occurs. However, to date, very few studies have quantified the behavioural interactions between humans and Anopheles vectors in Africa. Here, we characterized residual transmission in a rural area of Burkina Faso where long lasting insecticidal nets (LLIN) are widely used. Methods We analysed data on both human and malaria vectors behaviours from 27 villages to measure hourly human exposure to vector bites in dry and rainy seasons using a mathematical model. We estimated the protective efficacy of LLINs and characterised where (indoors vs. outdoors) and when both LLIN users and non-users were exposed to vector bites. Results The percentage of the population who declared sleeping under a LLIN the previous night was very high regardless of the season, with an average LLIN use ranging from 92.43 to 99.89%. The use of LLIN provided > 80% protection against exposure to vector bites. The proportion of exposure for LLIN users was 29–57% after 05:00 and 0.05–12% before 20:00. More than 80% of exposure occurred indoors for LLIN users and the estimate reached 90% for children under 5 years old in the dry cold season. Conclusions LLINs are predicted to provide considerable protection against exposure to malaria vector bites in the rural area of Diébougou. Nevertheless, LLIN users are still exposed to vector bites which occurred mostly indoors in late morning. Therefore, complementary strategies targeting indoor biting vectors in combination with LLIN are expected to be the most efficient to control residual malaria transmission in this area. Supplementary Information The online version contains supplementary material available at 10.1186/s12889-021-10304-y.
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Affiliation(s)
- D D Soma
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso. .,Université Nazi Boni (UNB), Bobo-Dioulasso, Burkina Faso. .,MIVEGEC, Univ. Montpellier, CNRS, IRD, Montpellier, France.
| | - B Zogo
- MIVEGEC, Univ. Montpellier, CNRS, IRD, Montpellier, France.,Institut Pierre Richet (IPR), Bouaké, Côte d'Ivoire.,Université d'Abomey Calavi, Abomey-Calavi, Benin
| | - P Taconet
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso.,MIVEGEC, Univ. Montpellier, CNRS, IRD, Montpellier, France
| | - A Somé
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso
| | - S Coulibaly
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso
| | | | - G A Ouédraogo
- Université Nazi Boni (UNB), Bobo-Dioulasso, Burkina Faso
| | - A Koffi
- Institut Pierre Richet (IPR), Bouaké, Côte d'Ivoire
| | - C Pennetier
- MIVEGEC, Univ. Montpellier, CNRS, IRD, Montpellier, France.,Institut Pierre Richet (IPR), Bouaké, Côte d'Ivoire
| | - K R Dabiré
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso
| | - N Moiroux
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso.,MIVEGEC, Univ. Montpellier, CNRS, IRD, Montpellier, France
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23
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Okiring J, Epstein A, Namuganga JF, Kamya V, Sserwanga A, Kapisi J, Ebong C, Kigozi SP, Mpimbaza A, Wanzira H, Briggs J, Kamya MR, Nankabirwa JI, Dorsey G. Relationships between test positivity rate, total laboratory confirmed cases of malaria, and malaria incidence in high burden settings of Uganda: an ecological analysis. Malar J 2021; 20:42. [PMID: 33441121 PMCID: PMC7805073 DOI: 10.1186/s12936-021-03584-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 01/07/2021] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Malaria surveillance is critical for monitoring changes in malaria morbidity over time. National Malaria Control Programmes often rely on surrogate measures of malaria incidence, including the test positivity rate (TPR) and total laboratory confirmed cases of malaria (TCM), to monitor trends in malaria morbidity. However, there are limited data on the accuracy of TPR and TCM for predicting temporal changes in malaria incidence, especially in high burden settings. METHODS This study leveraged data from 5 malaria reference centres (MRCs) located in high burden settings over a 15-month period from November 2018 through January 2020 as part of an enhanced health facility-based surveillance system established in Uganda. Individual level data were collected from all outpatients including demographics, laboratory test results, and village of residence. Estimates of malaria incidence were derived from catchment areas around the MRCs. Temporal relationships between monthly aggregate measures of TPR and TCM relative to estimates of malaria incidence were examined using linear and exponential regression models. RESULTS A total of 149,739 outpatient visits to the 5 MRCs were recorded. Overall, malaria was suspected in 73.4% of visits, 99.1% of patients with suspected malaria received a diagnostic test, and 69.7% of those tested for malaria were positive. Temporal correlations between monthly measures of TPR and malaria incidence using linear and exponential regression models were relatively poor, with small changes in TPR frequently associated with large changes in malaria incidence. Linear regression models of temporal changes in TCM provided the most parsimonious and accurate predictor of changes in malaria incidence, with adjusted R2 values ranging from 0.81 to 0.98 across the 5 MRCs. However, the slope of the regression lines indicating the change in malaria incidence per unit change in TCM varied from 0.57 to 2.13 across the 5 MRCs, and when combining data across all 5 sites, the R2 value reduced to 0.38. CONCLUSIONS In high malaria burden areas of Uganda, site-specific temporal changes in TCM had a strong linear relationship with malaria incidence and were a more useful metric than TPR. However, caution should be taken when comparing changes in TCM across sites.
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Affiliation(s)
- Jaffer Okiring
- Clinical Epidemiology Unit, School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda.
| | - Adrienne Epstein
- Department of Epidemiology and Biostatistics, University of California, San Francisco, USA
| | - Jane F Namuganga
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Victor Kamya
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Asadu Sserwanga
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - James Kapisi
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Chris Ebong
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Simon P Kigozi
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Arthur Mpimbaza
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | | | - Jessica Briggs
- Department of Medicine, University of California, San Francisco, USA
| | - Moses R Kamya
- Clinical Epidemiology Unit, School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Joaniter I Nankabirwa
- Clinical Epidemiology Unit, School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Grant Dorsey
- Department of Medicine, University of California, San Francisco, USA
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24
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Kua KP, Lee SWH. Randomized trials of housing interventions to prevent malaria and Aedes-transmitted diseases: A systematic review and meta-analysis. PLoS One 2021; 16:e0244284. [PMID: 33417600 PMCID: PMC7793286 DOI: 10.1371/journal.pone.0244284] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 12/08/2020] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Mosquito-borne diseases remain a significant public health problem in tropical regions. Housing improvements such as screening of doors and windows may be effective in reducing disease transmission, but the impact remains unclear. OBJECTIVES To examine whether housing interventions were effective in reducing mosquito densities in homes and the impact on the incidence of mosquito-borne diseases. METHODS In this systematic review and meta-analysis, we searched 16 online databases, including NIH PubMed, CINAHL Complete, LILACS, Ovid MEDLINE, and Cochrane Central Register of Controlled Trials for randomized trials published from database inception to June 30, 2020. The primary outcome was the incidence of any mosquito-borne diseases. Secondary outcomes encompassed entomological indicators of the disease transmission. I2 values were used to explore heterogeneity between studies. A random-effects meta-analysis was used to assess the primary and secondary outcomes, with sub-group analyses for type of interventions on home environment, study settings (rural, urban, or mixed), and overall house type (traditional or modern housing). RESULTS The literature search yielded 4,869 articles. After screening, 18 studies were included in the qualitative review, of which nine were included in the meta-analysis. The studies enrolled 7,200 households in Africa and South America, reporting on malaria or dengue only. The type of home environmental interventions included modification to ceilings and ribbons to close eaves, screening doors and windows with nets, insecticide-treated wall linings in homes, nettings over gables and eaves openings, mosquito trapping systems, metal-roofed houses with mosquito screening, gable windows and closed eaves, and prototype houses using southeast Asian designs. Pooled analysis depicted a lower risk of mosquito-borne diseases in the housing intervention group (OR = 0.68; 95% CI = 0.48 to 0.95; P = 0.03). Subgroup analysis depicted housing intervention reduced the risk of malaria in all settings (OR = 0.63; 95% CI = 0.39 to 1.01; P = 0.05). In urban environment, housing intervention was found to decrease the risk of both malaria and dengue infections (OR = 0.52; 95% CI = 0.27 to 0.99; P = 0.05).Meta-analysis of pooled odds ratio showed a significant benefit of improved housing in reducing indoor vector densities of both Aedes and Anopheles (OR = 0.35; 95% CI = 0.23 to 0.54; P<0.001). CONCLUSIONS Housing intervention could reduce transmission of malaria and dengue among people living in the homes. Future research should evaluate the protective effect of specific house features and housing improvements associated with urban development.
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Affiliation(s)
- Kok Pim Kua
- Puchong Health Clinic, Petaling District Health Office, Ministry of Health Malaysia, Petaling, Malaysia
| | - Shaun Wen Huey Lee
- School of Pharmacy, Monash University Malaysia, Sunway City, Malaysia
- Asian Center for Evidence Synthesis in Population, Implementation, and Clinical Outcomes (PICO), Health and Well-being Cluster, Global Asia in the 21st Century (GA21) Platform, Monash University Malaysia, Sunway City, Malaysia
- Gerontechnology Laboratory, Global Asia in the 21st Century (GA21) Platform, Monash University Malaysia, Sunway City, Malaysia
- Faculty of Health and Medical Sciences, Taylor's University, Subang Jaya, Malaysia
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25
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Canelas T, Thomsen E, McDermott D, Sternberg E, Thomas MB, Worrall E. Spatial targeting of Screening + Eave tubes (SET), a house-based malaria control intervention, in Côte d'Ivoire: A geostatistical modelling study. PLOS GLOBAL PUBLIC HEALTH 2021; 1:e0000030. [PMID: 36962107 PMCID: PMC10021308 DOI: 10.1371/journal.pgph.0000030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 10/18/2021] [Indexed: 11/18/2022]
Abstract
New malaria control tools and tailoring interventions to local contexts are needed to reduce the malaria burden and meet global goals. The housing modification, screening plus a targeted house-based insecticide delivery system called the In2Care® Eave Tubes, has been shown to reduce clinical malaria in a large cluster randomised controlled trial. However, the widescale suitability of this approach is unknown. We aimed to predict household suitability and define the most appropriate locations for ground-truthing where Screening + Eave Tubes (SET) could be implemented across Côte d'Ivoire. We classified DHS sampled households into suitable for SET based on the walls and roof materials. We fitted a Bayesian beta-binomial logistic model using the integrated nested Laplace approximation (INLA) to predict suitability of SET and to define priority locations for ground-truthing and to calculate the potential population coverage and costs. Based on currently available data on house type and malaria infection rate, 31% of the total population and 17.5% of the population in areas of high malaria transmission live in areas suitable for SET. The estimated cost of implementing SET in suitable high malaria transmission areas would be $46m ($13m -$108m). Ground-truthing and more studies should be conducted to evaluate the efficacy and feasibility of SET in these settings. The study provides an example of implementing strategies to reflect local socio-economic and epidemiological factors, and move beyond blanket, one-size-fits-all strategies.
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Affiliation(s)
- Tiago Canelas
- Vector Biology, Liverpool School of Tropical Medicine, Merseyside, United Kingdom
| | - Edward Thomsen
- Vector Biology, Liverpool School of Tropical Medicine, Merseyside, United Kingdom
| | - Daniel McDermott
- Vector Biology, Liverpool School of Tropical Medicine, Merseyside, United Kingdom
| | - Eleanore Sternberg
- Vector Biology, Liverpool School of Tropical Medicine, Merseyside, United Kingdom
| | - Matthew B Thomas
- Department of Entomology and Center for Infectious Disease Dynamics, The Pennsylvania State University, State College, Pennsylvania, United States of America
- York Environmental Sustainability Institute, University of York, Yorkshire, United Kingdom
| | - Eve Worrall
- Vector Biology, Liverpool School of Tropical Medicine, Merseyside, United Kingdom
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Barreaux AMG, Oumbouke WA, Brou N, Tia IZ, Ahoua Alou LP, Doudou DT, Koffi AA, N'Guessan R, Sternberg ED, Thomas MB. The role of human and mosquito behaviour in the efficacy of a house-based intervention. Philos Trans R Soc Lond B Biol Sci 2020; 376:20190815. [PMID: 33357057 PMCID: PMC7776932 DOI: 10.1098/rstb.2019.0815] [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] [Indexed: 11/21/2022] Open
Abstract
Housing improvement such as blocking eaves and screening windows can help in reducing exposure to indoor biting mosquitoes. The impacts of physical barriers could potentially be boosted by the addition of a mechanism that kills mosquitoes as they attempt to enter the house. One example is to combine household screening with EaveTubes, which are insecticide-treated tubes inserted into closed eaves that attract and kill host-searching mosquitoes. The epidemiological impact of screening + EaveTubes is being evaluated in a large cluster randomized trial in Cote d'Ivoire. The study presented here is designed as a complement to this trial to help better understand the functional roles of screening and EaveTubes. We began by evaluating householder behaviour and household condition in the study villages. This work revealed that doors (and to some extent windows) were left open for large parts of the evening and morning, and that even houses modified to make them more ‘mosquito proof’ often had possible entry points for mosquitoes. We next built two realistic experimental houses in a village to enable us to explore how these aspects of behaviour and household quality affected the impact of screening and EaveTubes. We found that screening could have a substantial impact on indoor mosquito densities, even with realistic household condition and behaviour. By contrast, EaveTubes had no significant impact on indoor mosquito density, either as a stand-alone intervention or in combination with screening. However, there was evidence that mosquitoes recruited to the EaveTubes, and the resulting mortality could create a community benefit. These complementary modes of action of screening and EaveTubes support the rationale of combining the technologies to create a ‘Lethal House Lure’. This article is part of the theme issue ‘Novel control strategies for mosquito-borne diseases’.
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Affiliation(s)
- Antoine M G Barreaux
- Center for Infectious Disease Dynamics and Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA.,School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
| | - Welbeck A Oumbouke
- Institut Pierre Richet/Institut National de Santé Publique (INSP), Bouaké, Cote d'Ivoire.,London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - N'Guessan Brou
- Institut Pierre Richet/Institut National de Santé Publique (INSP), Bouaké, Cote d'Ivoire
| | - Innocent Zran Tia
- Institut Pierre Richet/Institut National de Santé Publique (INSP), Bouaké, Cote d'Ivoire
| | - Ludovic P Ahoua Alou
- Institut Pierre Richet/Institut National de Santé Publique (INSP), Bouaké, Cote d'Ivoire
| | - Dimi Théodore Doudou
- Centre de recherche pour le Développement (CRD)/Laboratoire de Santé, Nutrition et Hygiène, Université Alassane Ouattara, Bouaké BP V 18 01, Cote d'Ivoire
| | - Alphonsine A Koffi
- Institut Pierre Richet/Institut National de Santé Publique (INSP), Bouaké, Cote d'Ivoire
| | - Raphaël N'Guessan
- Institut Pierre Richet/Institut National de Santé Publique (INSP), Bouaké, Cote d'Ivoire.,London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Eleanore D Sternberg
- Center for Infectious Disease Dynamics and Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA.,Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Matthew B Thomas
- Center for Infectious Disease Dynamics and Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA
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27
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Lindsay SW, Davies M, Alabaster G, Altamirano H, Jatta E, Jawara M, Carrasco-Tenezaca M, von Seidlein L, Shenton FC, Tusting LS, Wilson AL, Knudsen J. Recommendations for building out mosquito-transmitted diseases in sub-Saharan Africa: the DELIVER mnemonic. Philos Trans R Soc Lond B Biol Sci 2020; 376:20190814. [PMID: 33357059 DOI: 10.1098/rstb.2019.0814] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
In sub-Saharan Africa, most transmission of mosquito-transmitted diseases, such as malaria or dengue, occurs within or around houses. Preventing mosquito house entry and reducing mosquito production around the home would help reduce the transmission of these diseases. Based on recent research, we make key recommendations for reducing the threat of mosquito-transmitted diseases through changes to the built environment. The mnemonic, DELIVER, recommends the following best practices: (i) Doors should be screened, self-closing and without surrounding gaps; (ii) Eaves, the space between the wall and roof, should be closed or screened; (iii) houses should be Lifted above the ground; (iv) Insecticide-treated nets should be used when sleeping in houses at night; (v) houses should be Ventilated, with at least two large-screened windows to facilitate airflow; (vi) Environmental management should be conducted regularly inside and around the home; and (vii) Roofs should be solid, rather than thatch. DELIVER is a package of interventions to be used in combination for maximum impact. Simple changes to the built environment will reduce exposure to mosquito-transmitted diseases and help keep regions free from these diseases after elimination. This article is part of the theme issue 'Novel control strategies for mosquito-borne diseases'.
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Affiliation(s)
- Steven W Lindsay
- Department of Biosciences, Durham University, Durham DH1 3LE, UK
| | - Michael Davies
- Bartlett School Environment, Energy & Resources, Faculty of the Built Environment, University College London, London WC1H 0NN, UK
| | | | - Hector Altamirano
- Bartlett School Environment, Energy & Resources, Faculty of the Built Environment, University College London, London WC1H 0NN, UK
| | - Ebrima Jatta
- National Malaria Control Programme, Banjul, The Gambia
| | - Musa Jawara
- Medical Research Council Unit Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | | | - Lorenz von Seidlein
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Fiona C Shenton
- Department of Biosciences, Durham University, Durham DH1 3LE, UK
| | - Lucy S Tusting
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Anne L Wilson
- Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Jakob Knudsen
- The Royal Danish Academy of Fine Arts, School of Architecture, Design and Conservation, The School of Architecture, Copenhagen, Denmark
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28
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Carter R, Karunaweera ND. The role of improved housing and living environments in malaria control and elimination. Malar J 2020; 19:385. [PMID: 33129327 PMCID: PMC7603669 DOI: 10.1186/s12936-020-03450-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 10/16/2020] [Indexed: 11/10/2022] Open
Abstract
Malaria risk and endemicity is often associated with the nature of human habitation and living environment. The disappearance of malaria from regions where it had been endemic for centuries, such as coastal areas of southern England, has been attributed, at least in part, to improvement in the quality of housing. Moreover, indigenous malaria transmission ceased throughout England without the necessity to eliminate the vector mosquitoes. The principles of malaria transmission, as formulated following the thinking of the pioneers of malaria epidemiology, Ronald Ross and George Macdonald, show how this may happen. Malaria ceases to be sustainable where its reproduction number, R0, the number of new cases generated on average for each existing case of malaria, falls below 1. In the terms of a Ross/Macdonald analysis the reduced contact between humans and blood-feeding mosquitoes that is achieved through housing that is secure against mosquito entry can have a powerful effect in reducing malaria R0. The island of Sri Lanka, where malaria had been endemic probably for centuries previously, has reported no indigenous cases of malaria since 2012. The disappearance of malaria from Sri Lanka followed an effective attack upon malaria transmission by the Sri Lanka Anti Malaria Campaign. The targeted and enhanced efforts of this campaign launched in 1999, drove the malaria R0 below 1 for most of the period up to 2012, leading to a nearly continuous decline in malaria cases until their extinction. The decades leading up to the launch of these efforts were ones of general improvement of living environment and notably in the quality of housing stock. Studies in the late 1980s had shown that quality of housing in a highly malarious district of Sri Lanka was a strong determinant of malaria risk. Through its effects on malaria R0, improved housing is likely to have facilitated the malaria control and cessation of indigenous malaria transmission in Sri Lanka and that it will help reduce the risk of the re-introduction of malaria to the island.
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Affiliation(s)
- Richard Carter
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Nadira D Karunaweera
- Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka.
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29
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Zinszer K, Charland K, Vahey S, Jahagirdar D, Rek JC, Arinaitwe E, Nankabirwa J, Morrison K, Sadoine ML, Tutt-Guérette MA, Staedke SG, Kamya MR, Greenhouse B, Rodriguez-Barraquer I, Dorsey G. The Impact of Multiple Rounds of Indoor Residual Spraying on Malaria Incidence and Hemoglobin Levels in a High-Transmission Setting. J Infect Dis 2020; 221:304-312. [PMID: 31599325 DOI: 10.1093/infdis/jiz453] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 09/04/2019] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Indoor residual spraying (IRS) is widely used as a vector control measure, although there are conflicting findings of its effectiveness in reducing malaria incidence. The objective of this study was to estimate the effect of multiple IRS rounds on malaria incidence and hemoglobin levels in a cohort of children in rural southeastern Uganda. METHODS The study was based upon a dynamic cohort of children aged 0.5-10 years enrolled from August 2011 to June 2017 in Nagongera Subcounty. Confirmed malaria infections and hemoglobin levels were recorded over time for each participant. After each of 4 rounds of IRS, malaria incidence, hemoglobin levels, and parasite density were evaluated and compared with pre-IRS levels. Analyses were carried out at the participant level while accounting for repeated measures and clustering by household. RESULTS Incidence rate ratios comparing post-IRS to pre-IRS incidence rates for age groups 0-3, 3-5, and 5-11 were 0.108 (95% confidence interval [CI], .078-.149), 0.173 (95% CI, .136-.222), and 0.226 (95% CI, .187-.274), respectively. The mean hemoglobin levels significantly increased from 11.01 (pre-IRS) to 12.18 g/dL (post-IRS). CONCLUSIONS Our study supports the policy recommendation of IRS usage in a stable and perennial transmission area to rapidly reduce malaria transmission.
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Affiliation(s)
- Kate Zinszer
- Department of Social and Preventive Medicine, University of Montreal, Montreal, Quebec, Canada.,Centre de recherche en santé publique, University of Montreal, Montreal, Quebec, Canada
| | - Katia Charland
- Department of Social and Preventive Medicine, University of Montreal, Montreal, Quebec, Canada
| | - Sarah Vahey
- Centre de recherche en santé publique, University of Montreal, Montreal, Quebec, Canada
| | - Deepa Jahagirdar
- Institute for Health Metrics and Evaluation, Seattle, Washington, USA
| | - John C Rek
- Infectious Disease Research Collaboration, Makerere University, Kampala, Uganda
| | - Emmanuel Arinaitwe
- Infectious Disease Research Collaboration, Makerere University, Kampala, Uganda
| | - Joaniter Nankabirwa
- Infectious Disease Research Collaboration, Makerere University, Kampala, Uganda
| | | | - Margaux L Sadoine
- Department of Social and Preventive Medicine, University of Montreal, Montreal, Quebec, Canada.,Centre de recherche en santé publique, University of Montreal, Montreal, Quebec, Canada
| | - Marc-Antoine Tutt-Guérette
- Department of Social and Preventive Medicine, University of Montreal, Montreal, Quebec, Canada.,Centre de recherche en santé publique, University of Montreal, Montreal, Quebec, Canada
| | - Sarah G Staedke
- Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Moses R Kamya
- Infectious Disease Research Collaboration, Makerere University, Kampala, Uganda.,Department of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Bryan Greenhouse
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
| | | | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
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30
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Tusting LS, Gething PW, Gibson HS, Greenwood B, Knudsen J, Lindsay SW, Bhatt S. Housing and child health in sub-Saharan Africa: A cross-sectional analysis. PLoS Med 2020; 17:e1003055. [PMID: 32203504 PMCID: PMC7089421 DOI: 10.1371/journal.pmed.1003055] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 02/19/2020] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Housing is essential to human well-being but neglected in global health. Today, housing in Africa is rapidly improving alongside economic development, creating an urgent need to understand how these changes can benefit health. We hypothesised that improved housing is associated with better health in children living in sub-Saharan Africa (SSA). We conducted a cross-sectional analysis of housing conditions relative to a range of child health outcomes in SSA. METHODS AND FINDINGS Cross-sectional data were analysed for 824,694 children surveyed in 54 Demographic and Health Surveys, 21 Malaria Indicator Surveys, and two AIDS Indicator Surveys conducted in 33 countries between 2001 and 2017 that measured malaria infection by microscopy or rapid diagnostic test (RDT), diarrhoea, acute respiratory infections (ARIs), stunting, wasting, underweight, or anaemia in children aged 0-5 years. The mean age of children was 2.5 years, and 49.7% were female. Housing was categorised into a binary variable based on a United Nations definition comparing improved housing (with improved drinking water, improved sanitation, sufficient living area, and finished building materials) versus unimproved housing (all other houses). Associations between house type and child health outcomes were determined using conditional logistic regression within surveys, adjusting for prespecified covariables including age, sex, household wealth, insecticide-treated bed net use, and vaccination status. Individual survey odds ratios (ORs) were pooled using random-effects meta-analysis. Across surveys, improved housing was associated with 8%-18% lower odds of all outcomes except ARI (malaria infection by microscopy: adjusted OR [aOR] 0.88, 95% confidence intervals [CIs] 0.80-0.97, p = 0.01; malaria infection by RDT: aOR 0.82, 95% CI 0.77-0.88, p < 0.001; diarrhoea: aOR 0.92, 95% CI 0.88-0.97, p = 0.001; ARI: aOR 0.96, 95% CI 0.87-1.07, p = 0.49; stunting: aOR 0.83, 95% CI 0.77-0.88, p < 0.001; wasting: aOR 0.90, 95% CI 0.83-0.99, p = 0.03; underweight: aOR 0.85, 95% CI 0.80-0.90, p < 0.001; any anaemia: aOR 0.87, 95% CI 0.82-0.92, p < 0.001; severe anaemia: aOR 0.89, 95% CI 0.84-0.95, p < 0.001). In comparison, insecticide-treated net use was associated with 16%-17% lower odds of malaria infection (microscopy: aOR 0.83, 95% CI 0.78-0.88, p < 0.001; RDT: aOR 0.84, 95% CI 0.79-0.88, p < 0.001). Drinking water source and sanitation facility alone were not associated with diarrhoea. The main study limitations are the use of self-reported diarrhoea and ARI, as well as potential residual confounding by socioeconomic position, despite adjustments for household wealth and education. CONCLUSIONS In this study, we observed that poor housing, which includes inadequate drinking water and sanitation facility, is associated with health outcomes known to increase child mortality in SSA. Improvements to housing may be protective against a number of important childhood infectious diseases as well as poor growth outcomes, with major potential to improve children's health and survival across SSA.
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Affiliation(s)
- Lucy S. Tusting
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Peter W. Gething
- Big Data Institute, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Harry S. Gibson
- Big Data Institute, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Brian Greenwood
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Jakob Knudsen
- The Royal Danish Academy of Fine Arts, Schools of Architecture, Design and Conservation, Copenhagen, Denmark
| | - Steve W. Lindsay
- Department of Biosciences, Durham University, Durham, United Kingdom
| | - Samir Bhatt
- Big Data Institute, Nuffield Department of Medicine, University of Oxford, United Kingdom
- Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
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31
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Ngadjeu CS, Doumbe-Belisse P, Talipouo A, Djamouko-Djonkam L, Awono-Ambene P, Kekeunou S, Toussile W, Wondji CS, Antonio-Nkondjio C. Influence of house characteristics on mosquito distribution and malaria transmission in the city of Yaoundé, Cameroon. Malar J 2020; 19:53. [PMID: 32000786 PMCID: PMC6993434 DOI: 10.1186/s12936-020-3133-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 01/22/2020] [Indexed: 12/31/2022] Open
Abstract
Background Improving house structure is known to limit contact between humans and mosquitoes and reduce malaria transmission risk. In the present study, the influence of house characteristics on mosquito distribution and malaria transmission risk was assessed in the city of Yaoundé. Methods The study was conducted from March 2017 to June 2018 in 32 districts of the city of Yaoundé. Mosquito collections were performed indoor in 10 to 15 houses per district using CDC light traps. A total of 467 houses, selected randomly were used. A pretested questionnaire was submitted to participants of the study to collect information on the household: the number of people per house, education level, type of walls, presence of ceilings and eaves, number of windows, usage of long-lasting insecticidal nets (LLINs), number of bedroom and number of window. Mosquitoes collected were identified morphologically. Anophelines were tested by ELISA to detect infection by Plasmodium parasites. General Estimating Equations adjusting for repeated measures in the same house fitting negative binomial analysis were used to assess the influence of house characteristics on mosquito distribution. Results A total of 168,039 mosquitoes were collected; Culex spp emerged as the predominant species (96.48%), followed by Anopheles gambiae sensu lato (s.l.) (2.49%). Out of the 1033 An. gambiae s.l. identified by PCR, 90.03% were Anopheles coluzzii and the remaining were An. gambiae sensu stricto (s.s.) (9.97%). The high number of people per household, the presence of screens on window and the possession of LLINs were all associated with fewer mosquitoes collected indoors, whilst opened eaves, the high number of windows, the presence of holes in walls and living close to breeding sites were associated with high densities of mosquitoes indoor. Out of 3557 Anophelines tested using ELISA CSP, 80 were found infected by Plasmodium falciparum parasites. The proportion of mosquitoes infected did not vary significantly according to house characteristics. Conclusion The study indicated that several house characteristics such as, the presence of holes on walls, opened eaves, unscreened window and living close to breeding sites, favored mosquito presence in houses. Promoting frequent use of LLINs and house improvement measures, such as the use of screen on windows, closing eaves, cleaning the nearby environment, should be integrated in strategies to improve malaria control in the city of Yaoundé.
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Affiliation(s)
- Carmene S Ngadjeu
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon.,Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Patricia Doumbe-Belisse
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon.,Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Abdou Talipouo
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon.,Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Landre Djamouko-Djonkam
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon.,Faculty of Sciences, University of Dschang, P.O. Box 337, Dschang, Cameroon
| | - Parfait Awono-Ambene
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon
| | - Sevilor Kekeunou
- Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Wilson Toussile
- Ecole Nationale Supérieure Polytechnique University of Yaoundé I, P.O. Box 8390, Yaounde, Cameroon.,Faculty of Medicine Paris-Sud, 63 rue Gabriel Peri, 94276, Le Kremlin-Bicêtre, Paris, France
| | - Charles S Wondji
- Vector Biology Liverpool School of Tropical Medicine Pembroke Place, Liverpool, L3 5QA, UK
| | - Christophe Antonio-Nkondjio
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon. .,Vector Biology Liverpool School of Tropical Medicine Pembroke Place, Liverpool, L3 5QA, UK.
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32
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Peprah S, Tenge C, Genga IO, Mumia M, Were PA, Kuremu RT, Wekesa WN, Sumba PO, Kinyera T, Otim I, Legason ID, Biddle J, Reynolds SJ, Talisuna AO, Biggar RJ, Bhatia K, Goedert JJ, Pfeiffer RM, Mbulaiteye SM. A Cross-Sectional Population Study of Geographic, Age-Specific, and Household Risk Factors for Asymptomatic Plasmodium falciparum Malaria Infection in Western Kenya. Am J Trop Med Hyg 2019; 100:54-65. [PMID: 30457091 DOI: 10.4269/ajtmh.18-0481] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The burden of Plasmodium falciparum (Pf) malaria in Kenya is decreasing; however, it is still one of the top 10 causes of morbidity, particularly in regions of western Kenya. Between April 2015 and June 2016, we enrolled 965 apparently healthy children aged 0-15 years in former Nyanza and Western Provinces in Kenya to characterize the demographic, geographic, and household risk factors of asymptomatic malaria as part of an epidemiologic study to investigate the risk factors for endemic Burkitt lymphoma. The children were sampled using a stratified, multistage cluster sampling survey design. Malaria was assessed by rapid diagnostic test (RDT) and thick-film microscopy (TFM). Primary analyses of Pf malaria prevalence (pfPR) are based on RDT. Associations between weighted pfPR and potential risk factors were evaluated using logistic regression, accounting for the survey design. Plasmodium falciparum malaria prevalence was 36.0% (27.5%, 44.5%) by RDT and 22.3% (16.0%, 28.6%) by TFM. Plasmodium falciparum malaria prevalence was positively associated with living in the lake-endemic area (adjusted odds ratio [aOR] 3.46; 95% confidence interval [95% CI] 1.63, 7.37), paternal occupation as peasant farmer (aOR 1.87; 1.08, 3.26) or manual laborer (aOR 1.83; 1.00, 3.37), and keeping dogs (aOR 1.62; 0.98-2.69) or cows (aOR 1.52; 0.96-2.40) inside or near the household. Plasmodium falciparum malaria prevalence was inversely associated with indoor residual insecticide spraying (IRS) (aOR 0.44; 0.19, 1.01), having a household connected to electricity (aOR 0.47; 0.22, 0.98), and a household with two (aOR 0.45; 0.22, 0.93) or ≥ three rooms (aOR 0.41; 0.18, 0.93). We report high but geographically heterogeneous pfPR in children in western Kenya and significant associations with IRS and household-level socioeconomic factors.
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Affiliation(s)
- Sally Peprah
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland
| | | | - Isaiah O Genga
- EMBLEM Study, Academic Model Providing Access to Healthcare (AMPATH), Eldoret, Kenya
| | - Mediatrix Mumia
- EMBLEM Study, Academic Model Providing Access to Healthcare (AMPATH), Eldoret, Kenya
| | - Pamela A Were
- EMBLEM Study, Academic Model Providing Access to Healthcare (AMPATH), Eldoret, Kenya
| | | | | | | | - Tobias Kinyera
- EMBLEM Study, African Field Epidemiology Network, Kampala, Uganda
| | - Isaac Otim
- EMBLEM Study, African Field Epidemiology Network, Kampala, Uganda
| | - Ismail D Legason
- EMBLEM Study, African Field Epidemiology Network, Kampala, Uganda
| | - Joshua Biddle
- Stanford Hospitals and Clinics, University of Stanford, Pao Alto, California
| | - Steven J Reynolds
- National Institutes of Health/Uganda Project Entebbe, National Institute of Allergy and Infectious Diseases, Rockville, Maryland
| | - Ambrose O Talisuna
- World Health Organization, Regional Office for Africa, Brazzaville, Congo
| | - Robert J Biggar
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland
| | - Kishor Bhatia
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland
| | - James J Goedert
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland
| | - Ruth M Pfeiffer
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland
| | - Sam M Mbulaiteye
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland
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Rehman AM, Maiteki-Sebuguzi C, Gonahasa S, Okiring J, Kigozi SP, Chandler CIR, Drakeley C, Dorsey G, Kamya MR, Staedke SG. Intermittent preventive treatment of malaria delivered to primary schoolchildren provided effective individual protection in Jinja, Uganda: secondary outcomes of a cluster-randomized trial (START-IPT). Malar J 2019; 18:318. [PMID: 31533845 PMCID: PMC6751800 DOI: 10.1186/s12936-019-2954-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 09/07/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Intermittent preventive treatment (IPT) of malaria is recommended as policy for certain high-risk populations, but not currently for schoolchildren. A cluster-randomized trial was conducted to evaluate the effect of IPT with dihydroartemisinin-piperaquine (DP) on primary schoolchildren in Jinja, Uganda. Results of the impact of IPT of schoolchildren on community-level transmission have been reported previously. Here, secondary outcomes from a school-based survey are presented. METHODS Eighty-four clusters (one primary school plus 100 households) were randomized to intervention and control (1:1 ratio). Participants from intervention schools received monthly IPT with DP for up to 6 rounds (June-December 2014). At endline (November-December 2014), randomly selected children from all 84 schools were surveyed (13 per school) and thick blood smears were done. Those with fever or history of fever were tested with rapid diagnostic tests (RDTs) for malaria. Haemoglobin was measured in every fifth participant. Outcome measures included prevalence of asexual parasites and gametocytes (by microscopy), and prevalence of anaemia. Prevalence outcomes were analysed using generalized linear Poisson models with log link function, incorporating a cluster-level random intercept and quantified using prevalence risk ratios. RESULTS Among 23,280 students listed on the 42 intervention school registers, 10,079 (43.3%) aged 5-20 years were enrolled into the IPT intervention and received at least one dose of DP; of these, 9286 (92.1%) received at least one full (3-day) course. In total, 1092 children were enrolled into the final school survey (546 per arm) and had a thick blood smear done; of these, 255 had haemoglobin measured (129 intervention, 126 control). Children in the intervention arm were less likely to have asexual parasites (9.2% intervention vs 44.1% control, adjusted risk ratio [aRR] 0.22 [95% CI 0.16-0.30] p < 0.001), gametocytes (3.1% intervention vs 9.5% control, aRR 0.34 [95% CI 0.20-0.56] p < 0.001), fever (20.2% intervention vs 56.2% control, aRR 0.35 [95% CI 0.25-0.50] p < 0.001), or symptomatic malaria (5.1% intervention vs 35.7% control, aRR 0.14 [95% CI 0.08-0.26] p < 0.001). Prevalence of anaemia and mean haemoglobin were similar in both study arms. CONCLUSIONS School-aged children are a major reservoir of malaria parasites. Delivering IPT to schoolchildren would benefit individual children and may reduce transmission. School-based IPT could help to intensify malaria control toward elimination, and should be considered for policies and programmes. Trial registration Clinicaltrials.gov (NCT02009215), Registered 11 December 2013. https://clinicaltrials.gov/ct2/show/NCT02009215.
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Affiliation(s)
- Andrea M Rehman
- Department of Infectious Disease Epidemiology, LSHTM, London, UK
| | | | - Samuel Gonahasa
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda
| | - Jaffer Okiring
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda
| | - Simon P Kigozi
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda
| | - Clare I R Chandler
- Department of Global Health & Development, Department of Clinical Research, LSHTM, London, UK
| | | | - Grant Dorsey
- Department of Medicine, University of California, San Francisco, USA
| | - Moses R Kamya
- School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Sarah G Staedke
- Infectious Diseases Research Collaboration, PO Box 7475, Kampala, Uganda.
- Department of Clinical Research, London School of Hygiene & Tropical Medicine (LSHTM), London, UK.
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Corder RM, Paula GA, Pincelli A, Ferreira MU. Statistical modeling of surveillance data to identify correlates of urban malaria risk: A population-based study in the Amazon Basin. PLoS One 2019; 14:e0220980. [PMID: 31398228 PMCID: PMC6688813 DOI: 10.1371/journal.pone.0220980] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 07/28/2019] [Indexed: 11/22/2022] Open
Abstract
Despite the recent malaria burden reduction in the Americas, focal transmission persists across the Amazon Basin. Timely analysis of surveillance data is crucial to characterize high-risk individuals and households for better targeting of regional elimination efforts. Here we analyzed 5,480 records of laboratory-confirmed clinical malaria episodes combined with demographic and socioeconomic information to identify risk factors for elevated malaria incidence in Mâncio Lima, the main urban transmission hotspot of Brazil. Overdispersed malaria count data clustered into households were fitted with random-effects zero-inflated negative binomial regression models. Random-effect predictors were used to characterize the spatial heterogeneity in malaria risk at the household level. Adult males were identified as the population stratum at greatest risk, likely due to increased occupational exposure away of the town. However, poor housing and residence in the less urbanized periphery of the town were also found to be key predictors of malaria risk, consistent with a substantial local transmission. Two thirds of the 8,878 urban residents remained uninfected after 23,975 person-years of follow-up. Importantly, we estimated that nearly 14% of them, mostly children and older adults living in the central urban hub, were free of malaria risk, being either unexposed, naturally unsusceptible, or immune to infection. We conclude that statistical modeling of routinely collected, but often neglected, malaria surveillance data can be explored to characterize drivers of transmission heterogeneity at the community level and provide evidence for the rational deployment of control interventions.
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Affiliation(s)
- Rodrigo M. Corder
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- * E-mail: (RMC); (MUF)
| | - Gilberto A. Paula
- Department of Statistics, Institute of Mathematics and Statistics, University of São Paulo, São Paulo, Brazil
| | - Anaclara Pincelli
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Marcelo U. Ferreira
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- * E-mail: (RMC); (MUF)
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Saavedra MP, Conn JE, Alava F, Carrasco-Escobar G, Prussing C, Bickersmith SA, Sangama JL, Fernandez-Miñope C, Guzman M, Tong C, Valderrama C, Vinetz JM, Gamboa D, Moreno M. Higher risk of malaria transmission outdoors than indoors by Nyssorhynchus darlingi in riverine communities in the Peruvian Amazon. Parasit Vectors 2019; 12:374. [PMID: 31358033 PMCID: PMC6664538 DOI: 10.1186/s13071-019-3619-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 07/19/2019] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Malaria remains an important public health problem in Peru where incidence has been increasing since 2011. Of over 55,000 cases reported in 2017, Plasmodium vivax was the predominant species (76%), with P. falciparum responsible for the remaining 24%. Nyssorhynchus darlingi (previously Anopheles darlingi) is the main vector in Amazonian Peru, where hyperendemic Plasmodium transmission pockets have been found. Mazán district has pronounced spatial heterogeneity of P. vivax malaria. However, little is known about behavior, ecology or seasonal dynamics of Ny. darlingi in Mazán. This study aimed to gather baseline information about bionomics of malaria vectors and transmission risk factors in a hyperendemic malaria area of Amazonian Peru. METHODS To assess vector biology metrics, five surveys (two in the dry and three in the rainy season), including collection of sociodemographic information, were conducted in four communities in 2016-2017 on the Napo (Urco Miraño, URC; Salvador, SAL) and Mazán Rivers (Visto Bueno, VIB; Libertad, LIB). Human-biting rate (HBR), entomological inoculation rate (EIR) and human blood index (HBI) were measured to test the hypothesis of differences in entomological indices of Ny. darlingi between watersheds. A generalized linear mixed effect model (GLMM) was constructed to model the relationship between household risk factors and the EIR. RESULTS Nyssorhynchus darlingi comprised 95% of 7117 Anophelinae collected and its abundance was significantly higher along the Mazán River. The highest EIRs (3.03-4.54) were detected in March and June in URC, LIB and VIB, and significantly more Ny. darlingi were infected outdoors than indoors. Multivariate analysis indicated that the EIR was >12 times higher in URC compared with SAL. The HBI ranged from 0.42-0.75; humans were the most common blood source, followed by Galliformes and cows. There were dramatic differences in peak biting time and malaria incidence with similar bednet coverage in the villages. CONCLUSIONS Nyssorhynchus darlingi is the predominant contributor to malaria transmission in the Mazán District, Peru. Malaria risk in these villages is higher in the peridomestic area, with pronounced heterogeneities between and within villages on the Mazán and the Napo Rivers. Spatiotemporal identification and quantification of the prevailing malaria transmission would provide new evidence to orient specific control measures for vulnerable or at high risk populations.
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Affiliation(s)
- Marlon P. Saavedra
- 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, State University of New York-Albany, Albany, NY USA
- Wadsworth Center, New York State Department of Health, Albany, NY USA
| | | | - Gabriel Carrasco-Escobar
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigacion y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Catharine Prussing
- Department of Biomedical Sciences, School of Public Health, State University of New York-Albany, Albany, NY USA
| | | | - Jorge L. Sangama
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigacion y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Carlos Fernandez-Miñope
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigacion y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Mitchel Guzman
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigacion y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Carlos Tong
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigacion y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | | | - Joseph M. Vinetz
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigacion y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
- Division of Infectious Diseases, Department of Medicine, University of California San Diego, La Jolla, CA USA
- Present Address: Section of Infectious Diseases, Yale University School of Medicine, New Haven, CT USA
| | - Dionicia Gamboa
- Laboratorio ICEMR-Amazonia, Laboratorios de Investigacion y Desarrollo, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
- Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
- Instituto de Medicinal Tropical “Alexander von Humboldt”, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Marta Moreno
- Division of Infectious Diseases, Department of Medicine, University of California San Diego, La Jolla, CA USA
- Present Address: Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, UK
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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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Peprah S, Dhudha H, Ally H, Masalu N, Kawira E, Chao CN, Genga IO, Mumia M, Were PA, Kinyera T, Otim I, Legason ID, Biggar RJ, Bhatia K, Goedert JJ, Pfeiffer RM, Mbulaiteye SM. A population-based study of the prevalence and risk factors of low-grade Plasmodium falciparum malaria infection in children aged 0-15 years old in northern Tanzania. Trop Med Int Health 2019; 24:571-585. [PMID: 30843638 PMCID: PMC6499672 DOI: 10.1111/tmi.13225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVES Northern Tanzania experiences significant malaria-related morbidity and mortality, but accurate data are scarce. We update the data on patterns of low-grade Plasmodium falciparum malaria infection among children in northern Tanzania. METHODS Plasmodium falciparum malaria prevalence (pfPR) was assessed in a representative sample of 819 children enrolled in 94 villages in northern Tanzania between October 2015 and August 2016, using a complex survey design. Individual- and household-level risk factors for pfPR were elicited using structured questionnaires. pfPR was assessed using rapid diagnostic tests (RDTs) and thick film microscopy (TFM). Associations with pfPR, based on RDT, were assessed using adjusted odds ratios (aOR) and confidence intervals (CI) from weighted survey logistic regression models. RESULTS Plasmodium falciparum malaria prevalence (pfPR) was 39.5% (95% CI: 31.5, 47.5) by RDT and 33.4% (26.0, 40.6) by TFM. pfPR by RDT was inversely associated with higher-education parents, especially mothers (5-7 years of education: aOR 0.55; 95% CI: 0.31, 0.96, senior secondary education: aOR 0.10; 95% CI: 0.02, 0.55), living in a house near the main road (aOR 0.34; 95% CI: 0.15, 0.76), in a larger household (two rooms: aOR 0.40; 95% CI: 0.21, 0.79, more than two rooms OR 0.35; 95% CI: 0.20, 0.62). Keeping a dog near or inside the house was positively associated with pfPR (aOR 2.01; 95% CI: 1.26, 3.21). pfPR was not associated with bed-net use or indoor residual spraying. CONCLUSIONS Nearly 40% of children in northern Tanzania had low-grade malaria antigenaemia. Higher parental education and household metrics but not mosquito bed-net use were inversely associated with pfPR.
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Affiliation(s)
- Sally Peprah
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, USA
| | - Herry Dhudha
- EpideMiology of Burkitt Lymphoma in East African Children and Minors (EMBLEM) Study, Bugando Medical Center, Mwanza, Tanzania
| | - Hillary Ally
- EpideMiology of Burkitt Lymphoma in East African Children and Minors (EMBLEM) Study, Bugando Medical Center, Mwanza, Tanzania
| | - Nestory Masalu
- EpideMiology of Burkitt Lymphoma in East African Children and Minors (EMBLEM) Study, Bugando Medical Center, Mwanza, Tanzania
| | - Esther Kawira
- EMBLEM Study, Shirati Health and Educational Foundation, Shirati, Tanzania
| | - Colin N Chao
- EpideMiology of Burkitt Lymphoma in East African Children and Minors (EMBLEM) Study, Bugando Medical Center, Mwanza, Tanzania
| | - Isaiah O. Genga
- EMBLEM Study, Academic Model Providing Access to Healthcare, Eldoret, Kenya
| | - Mediatrix Mumia
- EMBLEM Study, Academic Model Providing Access to Healthcare, Eldoret, Kenya
| | - Pamela A. Were
- EMBLEM Study, Academic Model Providing Access to Healthcare, Eldoret, Kenya
| | - Tobias Kinyera
- EMBLEM Study, African Field Epidemiology Network, Kampala, Uganda
| | - Isaac Otim
- EMBLEM Study, African Field Epidemiology Network, Kampala, Uganda
| | | | - Robert J. Biggar
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, USA
| | - Kishor Bhatia
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, USA
| | - James J. Goedert
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, USA
| | - Ruth M. Pfeiffer
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, USA
| | - Sam M. Mbulaiteye
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, Maryland, USA
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Okiring J, Olwoch P, Kakuru A, Okou J, Ochokoru H, Ochieng TA, Kajubi R, Kamya MR, Dorsey G, Tusting LS. Household and maternal risk factors for malaria in pregnancy in a highly endemic area of Uganda: a prospective cohort study. Malar J 2019; 18:144. [PMID: 31014336 PMCID: PMC6480498 DOI: 10.1186/s12936-019-2779-x] [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: 01/09/2019] [Accepted: 04/13/2019] [Indexed: 11/23/2022] Open
Abstract
Background Malaria in pregnancy is a major public health challenge, but its risk factors remain poorly understood in some settings. This study assessed the association between household and maternal characteristics and malaria among pregnant women in a high transmission area of Uganda. Methods A nested prospective study was conducted between 6th September 2016 and 5th December 2017 in Busia district. 782 HIV uninfected women were enrolled in the parent study with convenience sampling. Socioeconomic and house construction data were collected via a household survey after enrolment. Homes were classified as modern (plaster or cement walls, metal or wooden roof and closed eaves) or traditional (all other homes). Maternal and household risk factors were evaluated for three outcomes: (1) malaria parasitaemia at enrolment, measured by thick blood smear and qPCR, (2) malaria parasitaemia during pregnancy following initiation of IPTp, measured by thick blood smear and qPCR and (3) placental malaria measured by histopathology. Results A total of 753 of 782 women were included in the analysis. Most women had no or primary education (75%) and lived in traditional houses (77%). At enrolment, microscopic or sub-microscopic parasitaemia was associated with house type (traditional versus modern: adjusted risk ratio (aRR) 1.29, 95% confidence intervals 1.15–1.45, p < 0.001), level of education (primary or no education versus O-level or beyond: aRR 1.13, 95% confidence interval 1.02–1.24, p = 0.02), and gravidity (primigravida versus multigravida: aRR 1.10, 95% confidence interval 1.02–1.18, p = 0.009). After initiation of IPTp, microscopic or sub-microscopic parasitaemia was associated with wealth index (poorest versus least poor: aRR 1.24, 95% CI 1.10–1.39, p < 0.001), house type (aRR 1.14, 95% CI 1.01–1.28, p = 0.03), education level (aRR 1.19, 95% CI 1.06–1.34, p = 0.002) and gravidity (aRR 1.32, 95% CI 1.20–1.45, p < 0.001). Placental malaria was associated with gravidity (aRR 2.87, 95% CI 2.39–3.45, p < 0.001), but not with household characteristics. Conclusions In an area of high malaria transmission, primigravid women and those belonging to the poorest households, living in traditional homes and with the least education had the greatest risk of malaria during pregnancy.
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Affiliation(s)
- Jaffer Okiring
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda.
| | - Peter Olwoch
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Abel Kakuru
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Joseph Okou
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Harriet Ochokoru
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Tedy Andra Ochieng
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Richard Kajubi
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Moses R Kamya
- Makerere University College of Health Sciences, Kampala, Uganda
| | - Grant Dorsey
- University of California, San Francisco, San Francisco, CA, 94110, USA
| | - Lucy S Tusting
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
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Tusting LS, Bisanzio D, Alabaster G, Cameron E, Cibulskis R, Davies M, Flaxman S, Gibson HS, Knudsen J, Mbogo C, Okumu FO, von Seidlein L, Weiss DJ, Lindsay SW, Gething PW, Bhatt S. Mapping changes in housing in sub-Saharan Africa from 2000 to 2015. Nature 2019; 568:391-394. [PMID: 30918405 PMCID: PMC6784864 DOI: 10.1038/s41586-019-1050-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 02/20/2019] [Indexed: 11/16/2022]
Abstract
Access to adequate housing is a fundamental human right, essential to human security, nutrition and health, and a core objective of the United Nations Sustainable Development Goals1,2. Globally, the housing need is most acute in Africa, where the population will more than double by 2050. However, existing data on housing quality across Africa are limited primarily to urban areas and are mostly recorded at the national level. Here we quantify changes in housing in sub-Saharan Africa from 2000 to 2015 by combining national survey data within a geostatistical framework. We show a marked transformation of housing in urban and rural sub-Saharan Africa between 2000 and 2015, with the prevalence of improved housing (with improved water and sanitation, sufficient living area and durable construction) doubling from 11% (95% confidence interval, 10-12%) to 23% (21-25%). However, 53 (50-57) million urban Africans (47% (44-50%) of the urban population analysed) were living in unimproved housing in 2015. We provide high-resolution, standardized estimates of housing conditions across sub-Saharan Africa. Our maps provide a baseline for measuring change and a mechanism to guide interventions during the era of the Sustainable Development Goals.
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Affiliation(s)
- Lucy S Tusting
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK.
| | - Donal Bisanzio
- RTI International, Washington, DC, USA
- Division of Epidemiology and Public Health, School of Medicine, University of Nottingham, Nottingham, UK
| | | | - Ewan Cameron
- Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Richard Cibulskis
- Health Metrics and Measurement Cluster, World Health Organization, Geneva, Switzerland
| | - Michael Davies
- UCL Institute for Environmental Design and Engineering (IEDE), University College London, London, UK
| | - Seth Flaxman
- Department of Mathematics and Data Science Institute, Imperial College London, London, UK
| | - Harry S Gibson
- Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Jakob Knudsen
- School of Architecture, The Royal Danish Academy of Fine Arts, Copenhagen, Denmark
| | - Charles Mbogo
- Kenya Medical Research Institute, Kilifi, Kenya
- KEMRI-Wellcome Trust Research Program, Nairobi, Kenya
| | - Fredros O Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Lorenz von Seidlein
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Daniel J Weiss
- Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | | | - Peter W Gething
- Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Samir Bhatt
- Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Department of Infectious Disease Epidemiology, Imperial College London, London, UK
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Killeen GF, Govella NJ, Mlacha YP, Chaki PP. Suppression of malaria vector densities and human infection prevalence associated with scale-up of mosquito-proofed housing in Dar es Salaam, Tanzania: re-analysis of an observational series of parasitological and entomological surveys. Lancet Planet Health 2019; 3:e132-e143. [PMID: 30904112 DOI: 10.1016/s2542-5196(19)30035-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 02/15/2019] [Accepted: 02/18/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND In the city of Dar es Salaam, Tanzania, rapid and spontaneous scale-up of window screening occurred through purely horizontal commercial distribution systems without any public subsidies or promotion. Scale-up of window screening coincided with a planned evaluation of programmatic, vertically managed scale-up of regular larvicide application as an intervention against malaria vectors and transmission. We aimed to establish whether scale-up of window screening was associated with suppression of mosquito populations, especially for malaria vectors that strongly prefer humans as their source of blood. METHODS This study was a re-analysis of a previous observational series of epidemiological data plus new analyses of previously partly reported complementary entomological data, from Dar es Salaam. Between 2004 and 2008, six rounds of cluster-sampled, rolling, cross-sectional parasitological and questionnaire surveys were done in urban Dar es Salaam to assess the effect of larviciding and other determinants of malaria risk, such as use of bed nets and antimalarial drugs, socioeconomic status, age, sex, travel history, mosquito-proofed housing, and spending time outdoors. The effects of scaled-up larvicide application and window screening were estimated by fitting generalised linear mixed models that allowed for both spatial variation between survey locations and temporal autocorrelation within locations. We also conducted continuous longitudinal entomological surveys of outdoor human biting rates by mosquitoes and experimental measurements of mosquito host preferences. FINDINGS Best-fit models of Plasmodium falciparum malaria infection prevalence among humans were largely consistent with the results of the previous analyses. Re-analysis of previously reported epidemiological data revealed that most of the empirically fitted downward time trend in P falciparum malaria prevalence over the course of the study (odds ratio [OR] 0·04; 95% CI 0·03-0·06; p<0·0001), which was not previously reported numerically or attributed to any explanatory factor, could be plausibly explained by association with an upward trend in city-wide window screening coverage (OR 0·07; 0·05-0·09; p<0·0001) and progressive rollout of larviciding (OR 0·50; 0·41-0·60; p<0·0001). Increasing coverage of complete window screening was also associated with reduced biting densities of all taxonomic groups of mosquitoes (all p<0·0001), especially the Anopheles gambiae complex (relative rate [RR] 0·23; 95% CI 0·16-0·33) and Anopheles funestus group (RR 0·08; 0·04-0·16), which were confirmed as the most efficient vectors of malaria with strong preferences for humans over cattle. Larviciding was also associated with reduced biting densities of all mosquito taxa (p<0·0001), to an extent that varied consistently with the larvicide targeting scheme and known larval ecology of each taxon. INTERPRETATION Community-wide mosquito proofing of houses might deliver greater impacts on vector populations and malaria transmission than previously thought. The spontaneous nature of the scale-up observed here is also encouraging with regards to practicality, acceptability, and affordability in low-income settings. FUNDING United States Agency for International Development, Bill & Melinda Gates Foundation, Wellcome Trust, and Valent BioSciences LLC.
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Affiliation(s)
- Gerry F Killeen
- Ifakara Health Institute, Department of Environmental Health and Ecological Sciences, Dar es Salaam, Tanzania; Liverpool School of Tropical Medicine, Department of Vector Biology, Liverpool, UK.
| | - Nicodem J Govella
- Ifakara Health Institute, Department of Environmental Health and Ecological Sciences, Dar es Salaam, Tanzania
| | - Yeromin P Mlacha
- Ifakara Health Institute, Department of Environmental Health and Ecological Sciences, Dar es Salaam, Tanzania
| | - Prosper P Chaki
- Ifakara Health Institute, Department of Environmental Health and Ecological Sciences, Dar es Salaam, Tanzania
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Spielmeyer A, Schetelig MF, Etang J. High-throughput analysis of insecticides on malaria vectors using liquid chromatography tandem mass spectrometry. PLoS One 2019; 14:e0211064. [PMID: 30730918 PMCID: PMC6366735 DOI: 10.1371/journal.pone.0211064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 12/21/2018] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Different setups and protocols have been developed for investigating insecticide effects on Anopheles (An.) mosquitoes, vectors of malaria. However, chemical uptake resulting from their tarsal contact with insecticide-treated material has seldom been investigated. To address the challenges encountered in the interpretation of bioassay data, a high throughput method for chemical analysis on malaria vectors was developed and validated for five selected insecticides including alpha-cypermethrin (aCYP), deltamethrin (DM), etofenprox (EPX), permethrin (PM), pirimiphos-methyl (PPM). METHODS The method includes a single chemical extraction step via an ultrasound probe on mosquito samples and analysis via liquid chromatography coupled to high-resolution tandem mass spectrometry (UHPLC-MS/MS). The protocol was established for two malaria vector species, Anopheles gambiae senso stricto (s.s.) and An. stephensi, both males and females. Recovery rates ranged from 70 to 100% without any influence of sex or species. The method was efficiently applied to female An. gambiae s.s. of the KISUMU1 reference strain, after susceptibility tests using the World Health Organization's standard protocol. RESULTS Susceptibility tests revealed 13.4-18.4 minutes knockdown times for 50% mosquitoes during exposure to EPX and pyrethroids. The mortality rates 24 hours post-exposure to insecticides were mostly 99-100%, except in two PM and three PPM assays suggesting possible or confirmed resistance to these insecticides. The mean insecticide uptake in dead mosquitoes ranged from 23 pg (aCYP) to 1812 pg (EPX) per specimen. However, the mean uptake in survivors to PM and PPM was reduced by at least 25%, suggesting that acute doses were not achieved in these specimens during bioassays. CONCLUSIONS The developed and validated UHPLC-MS/MS method could be used to address some limitations of bioassays or to assess the penetration of insecticides in mosquito matrix with reference to cuticle thickness and other insecticide resistance mechanisms.
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Affiliation(s)
- Astrid Spielmeyer
- Justus Liebig University Giessen, Institute for Food Chemistry and Food Biotechnology, Giessen, Germany
| | - Marc F. Schetelig
- Justus Liebig University Giessen, Institute for Insect Biotechnology, Giessen, Germany
| | - Josiane Etang
- Justus Liebig University Giessen, Institute for Insect Biotechnology, Giessen, Germany
- Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Institut de Recherche de Yaoundé (IRY), Yaoundé, Cameroun
- University of Douala, Faculty of Medicine and Pharmaceutical Sciences, Douala, Cameroon
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42
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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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Kang SY, Battle KE, Gibson HS, Cooper LV, Maxwell K, Kamya M, Lindsay SW, Dorsey G, Greenhouse B, Rodriguez-Barraquer I, Reiner RCJ, Smith DL, Bisanzio D. Heterogeneous exposure and hotspots for malaria vectors at three study sites in Uganda. Gates Open Res 2018; 2:32. [PMID: 30706054 PMCID: PMC6350504 DOI: 10.12688/gatesopenres.12838.2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/01/2018] [Indexed: 11/30/2022] Open
Abstract
Background: Heterogeneity in malaria transmission has household, temporal, and spatial components. These factors are relevant for improving the efficiency of malaria control by targeting heterogeneity. To quantify variation, we analyzed mosquito counts from entomological surveillance conducted at three study sites in Uganda that varied in malaria transmission intensity. Mosquito biting or exposure is a risk factor for malaria transmission. Methods: Using a Bayesian zero-inflated negative binomial model, validated via a comprehensive simulation study, we quantified household differences in malaria vector density and examined its spatial distribution. We introduced a novel approach for identifying changes in vector abundance hotspots over time by computing the Getis-Ord statistic on ratios of household biting propensities for different scenarios. We also explored the association of household biting propensities with housing and environmental covariates. Results: In each site, there was evidence for hot and cold spots of vector abundance, and spatial patterns associated with urbanicity, elevation, or other environmental covariates. We found some differences in the hotspots in rainy vs. dry seasons or before vs. after the application of control interventions. Housing quality explained a portion of the variation among households in mosquito counts. Conclusion: This work provided an improved understanding of heterogeneity in malaria vector density at the three study sites in Uganda and offered a valuable opportunity for assessing whether interventions could be spatially targeted to be aimed at abundance hotspots which may increase malaria risk. Indoor residual spraying was shown to be a successful measure of vector control interventions in Tororo, Uganda. Cement walls, brick floors, closed eaves, screened airbricks, and tiled roofs were features of a house that had shown reduction of household biting propensity. Improvements in house quality should be recommended as a supplementary measure for malaria control reducing risk of infection.
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Affiliation(s)
- Su Yun Kang
- Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Katherine E Battle
- Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Harry S Gibson
- Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Laura V Cooper
- Department of Veterinary Medicine, Cambridge University, Cambridge, UK
| | - Kilama Maxwell
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Moses Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | - Grant Dorsey
- Department of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Bryan Greenhouse
- Department of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | | | - Robert C Jr Reiner
- Institute for Health Metrics & Evaluation, University of Washington, Seattle, WA, USA
| | - David L Smith
- Institute for Health Metrics & Evaluation, University of Washington, Seattle, WA, USA
| | - Donal Bisanzio
- RTI International, Washington DC, USA.,Centre for Tropical Diseases, Sacro Cuore-Don Calabria Hospital, Negrar, Italy
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44
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Kang SY, Battle KE, Gibson HS, Cooper LV, Maxwell K, Kamya M, Lindsay SW, Dorsey G, Greenhouse B, Rodriguez-Barraquer I, Reiner RCJ, Smith DL, Bisanzio D. Heterogeneous exposure and hotspots for malaria vectors at three study sites in Uganda. Gates Open Res 2018. [DOI: 10.12688/gatesopenres.12838.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background: Heterogeneity in malaria transmission has household, temporal, and spatial components. These factors are relevant for improving the efficiency of malaria control by targeting heterogeneity. To quantify variation, we analyzed mosquito counts from entomological surveillance conducted at three study sites in Uganda that varied in malaria transmission intensity. Methods: Using a Bayesian zero-inflated negative binomial model, validated via a comprehensive simulation study, we quantified household differences in malaria vector density and examined its spatial distribution. We introduced a novel approach for identifying changes in malaria hotspots over time by computing the Getis-Ord statistic on ratios of household biting propensities for different scenarios. We also explored the association of household biting propensities with housing and environmental covariates. Results: In each site, there was evidence for hot and cold spots, spatial patterns associated with urbanicity, elevation, or other environmental covariates. We found some differences in the hotspots in rainy vs. dry seasons or before vs. after the application of control interventions. Housing quality explained a portion of the variation among households in mosquito counts. Conclusion: This work provided an improved understanding of heterogeneity in malaria vector density at the three study sites in Uganda and offered a valuable opportunity for assessing whether interventions could be spatially targeted to be aimed at hotspots of malaria risk. Indoor residual spraying was shown to be a successful measure of vector control interventions in Tororo, Uganda. Cement walls, brick floors, closed eaves, screened airbricks, and tiled roofs were features of a house that had shown protective effects towards malaria risk. Improvements in house quality should be recommended as a supplementary measure for malaria control.
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