Passive cooling options in combination with vector proofing for indoor heat reduction and mosquito control: a pilot study in rural western Kenya

Abstract

Background The rapid increase in global temperatures coupled with persistent malaria transmission has significant public health ramifications, especially in Sub-Saharan Africa. Indoor thermal comfort and malaria transmission depend on building designs and structural properties of houses. This study assessed the impact of housing modification, combining passive cooling options with vector proofing for indoor temperature reduction and mosquito control. Methods Forty houses were randomly allocated to one of four arms: reflective roof, cross ventilation, mat ceiling or control. Additionally, doors, windows and eaves of the intervention houses were screened for vector proofing. Indoor temperatures and humidity were monitored daily whereas, mosquito numbers were assessed monthly. Community knowledge, attitude, and perception were assessed using structured questionnaires. Findings Female An. funestus were 67% lower in screened compared to unscreened houses after modification and 6-fold higher before compared to after screening. Houses with reflective roofs and mat ceilings had significantly lower mean day temperature compared to the control, RR=0.08: 95%CI (0.04-0.17) and RR=0.35: 95%CI (0.17-0.74) respectively. At night, houses with cross ventilation and mat ceiling had significantly higher temperatures compared to the control, RR=2.35:95%CI (1.45-3.84) and RR=6.66: 95%CI (4.09-10.85) respectively. Up to 85% of the households expressed willingness to use their resources to modify their houses. Interpretation The combinations of cool roofs and vector proofing are effective for the reduction of indoor temperatures and mosquito control in rural African houses. Cross ventilation is prone to user bias as it relies on household members keeping their doors and windows open for air circulation and cooling whereas mat ceilings are effective in keeping indoor temperature low during the day but are relatively warm at night. Funding Funded by SeaFright Labs through Habitat for Humanity International.