Differential behaviour of endophilic <i>Anopheles</i> mosquitoes in rooms occupied by tobacco smokers and non-smokers in two Nigerian villages

Abstract

The behavioural effect of tobacco smoke on endophilic Anopheles mosquitoes was observed in two North Central Nigerian villages. Pyrethrum spray and exit trap collections of mosquitoes were conducted, between April and November 2014, in two different villages where tobacco smoking was common among the residents. Anopheles mosquito samples collected were identified to sibling species level using species-specific polymerase chain reaction. Presence of human blood in the blood-fed mosquitoes was determined by Enzyme-linked immunosorbent assay. Numbers of mosquitoes collected from the rooms inhabited by tobacco smokers and non-smokers were compared using Student’s t-test (p<0.05). At least four times higher exit rates, five times less gravid females and significantly lower numbers of An. gambiae s.l mosquitoes were found in rooms inhabited by tobacco smokers compared to equal sized rooms occupied by non-smokers in each village. Blood feeding rates (77-88%) and human blood indices (0.82-0.87) of mosquitoes were generally high in the habitations of both tobacco smokers and non-smokers. There was predominance of An. gambiae (≥ 86%) species compared to An. coluzzii (≤ 14%) in both villages. Reduced mosquito endophily was observed in the habitations of tobacco smokers compared to the non-smokers. Widespread tobacco smoking habits should be investigated for possible contributions to mosquito behavioural resistance and residual malaria parasite transmission within rural communities.

Keywords: Anopheles mosquitoes, Tobacco Smoke, Exophily, Malaria