Do topical repellents divert mosquitoes within a community? Health equity implications of topical repellents as a mosquito bite prevention tool.

OBJECTIVES: Repellents do not kill mosquitoes--they simply reduce human-vector contact. Thus it is possible that individuals who do not use repellents but dwell close to repellent users experience more bites than otherwise. The objective of this study was to measure if diversion occurs from households that use repellents to those that do not use repellents. METHODS: The study was performed in three Tanzanian villages using 15%-DEET and placebo lotions. All households were given LLINs. Three coverage scenarios were investigated: complete coverage (all households were given 15%-DEET), incomplete coverage (80% of households were given 15%-DEET and 20% placebo) and no coverage (all households were given placebo). A crossover study design was used and coverage scenarios were rotated weekly over a period of ten weeks. The placebo lotion was randomly allocated to households in the incomplete coverage scenario. The level of compliance was reported to be close to 100%. Mosquito densities were measured through aspiration of resting mosquitoes. Data were analysed using negative binomial regression models. FINDINGS: Repellent-users had consistently fewer mosquitoes in their dwellings. In villages where everybody had been given 15%-DEET, resting mosquito densities were fewer than half that of households in the no coverage scenario (Incidence Rate Ratio [IRR]=0.39 (95% confidence interval [CI]: 0.25-0.60); p<0.001). Placebo-users living in a village where 80% of the households used 15%-DEET were likely to have over four-times more mosquitoes (IRR=4.17; 95% CI: 3.08-5.65; p<0.001) resting in their dwellings in comparison to households in a village where nobody uses repellent. CONCLUSIONS: There is evidence that high coverage of repellent use could significantly reduce man-vector contact but with incomplete coverage evidence suggests that mosquitoes are diverted from households that use repellent to those that do not. Therefore, if repellents are to be considered for vector control, strategies to maximise coverage are required

The economic impacts of house screening against malaria transmission : Experimental evidence from eastern Zambia

Malaria imposes an economic burden for human populations in many African countries, and this burden may be reduced through house screening initiatives. We use a randomized controlled trial to measure the economic impacts of house screening against malaria infection. We use a sample of 800 households from 89 villages in rural and peri-urban Zambia to collect baseline data in August 2019 and endline data in August 2020. The main outcome variables are (self-reported) malaria prevalence rates, labor supply, and income, and consider individual and household-level outcomes. House screening reduces malaria prevalence, the number of sick days due to malaria, and the number of malaria episodes. Impacts on adults are more pronounced than on children. In terms of economic impacts, house screening increases labor supply and (household) income. We find particularly large effects on labor supply for women household members. A cost-benefit analysis, based on estimated benefits and measured costs, suggests that the private benefits of house screening exceed the costs. While not all houses are suitable for house screening, we conclude that screening is a promising and cost-effective approach to reduce malaria infections

Mosquito collection sites and some households of the Mbingu area, Kilombero Valley, Tanzania.

<p>A – Household made with thatch wall and thatch roof with a blue barrel and a car tyre serving as artificial resting places. B – Household made with brick walls and thatch roof, the artificial resting places are not visible because they were deployed behind the household. C – Household made of mud walls and thatch roof with a blue barrel and a car tyre serving as artificial resting places. D – <i>Kibanda</i>, outdoor kitchen area.</p

Vector control for malaria elimination in Botswana : progress, gaps and opportunities

Botswana has in the recent past 10 years made tremendous progress in the control of malaria and this informed re-orientation from malaria control to malaria elimination by the year 2020. This progress is attributed to improved case management, and scale-up of key vector control interventions; indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs). However, insecticide resistance, outdoor biting and resting, and predisposing human behaviour, such as staying outdoors or sleeping outdoors without the use of protective measures, pose a challenge to the realization of the full impact of LLINs and IRS. This, together with the paucity of entomological data, inadequate resources and weak community participation for vector control programme implementation delayed attainment of Botswana’s goal of malaria elimination. Also, the Botswana National Malaria Programme (NMP) experiences the lack of intersectoral collaborations and operational research for evidence-based decision making. This case study focuses on the vector control aspect of malaria elimination by identifying challenges and explores opportunities that could be taken advantage of to benefit the NMP to optimize and augment the current vector control interventions to achieve malaria elimination by the year 2030 as per the Global Technical Strategy for Malaria 2016–2030 targets. The authors emphasize the need for timely and quality entomological surveillance, operational research and integrated vector management.Funding for this review was provided by the AFRO-II Project which is supported by Global Environment Facility/United Nations Environment Programme (GEF/UNEP) through World Health Organization Regional Office for Africa (WHO-AFRO).The AFRO-II Project which is supported by Global Environment Facility/United Nations Environment Programme (GEF/UNEP) through World Health Organization Regional Office for Africa (WHO-AFRO).http://www.malariajournal.comam2020School of Health Systems and Public Health (SHSPH