Influence of room air quality and microclimate on the abundance of mosquito vectors from the Sahel Region, Republic of Niger

Background The transmission of vector-borne diseases such as malaria depends largely on the ability of the pathogen transmitting mosquitoes to bite and rest indoors. However, the density of mosquitoes indoors is limited by microclimate such as temperature, Relative Humidity, fine particles and volatile organic compounds in the air. In this study, we assessed the impact of environmental conditions, including temperature, Relative Humidity (RH), and indoor air quality between August and October 2024, on the abundance of Culicidae mosquitoes. Mosquitoes were captured using Prokopack aspirators and morphologically identified to genera levels using dichotomous keys. Results A total of 110 rooms were sampled and 1,803 mosquitoes were captured, including 1,702 Anopheles , 97 Culex and 4 Aedes . The average temperature was 29.1°C, and the Relative Humidity (RH) ranged between 45% and 65%. A negative relationship was established between mosquito abundance and room temperature (r = − 0.25), with a sharp decline in indoor abundance observed when temperatures exceeded the average of 29.1°C. No significant correlation was found between mosquito abundance and RH (r = 0.18; p > 0.05). However, this relationship is positive for fine particles (PM2.5, PM1.0, and PM10) (r varying between 0.21 and 0.28). Conclusions This study shows that the abundance of the indoor mosquitoes correlates with air quality, more specifically with the higher permissive temperature and concentration of fine particles in the air inside houses. Future studies should focus on the dynamics of the Anopheles populations in relation to indoor air quality, to better target the appropriate time for intervention.