Entomological and transmission risk indices of malaria vectors in selected communities in Osun state, Nigeria

Abstract

Baseline survey is an integral component of a malaria vector control programme, providing valuable information on mosquito behaviour that guide the suitability of chosen interventions. A need assessment of baseline entomological indices towards the future implementation of indoor residual spray (IRS) was conducted in Osun State, Nigeria. Indoor resting mosquitoes were collected in human households from three Local
Government Areas. These were morphologically identified, subjected to species specific polymerase chain reaction (PCR) assay and analyzed for sporozoite infection and blood meal origin using enzyme linked   immunosorbent assay (ELISA). All female Anopheles identified fed on human blood but tested negative to Plasmodium falciparum circumsporozoite antigen. The PCR analysis showed a predominance of An. gambiae s.s. (95%) over An. arabiensis (5%). The preponderance of indoor resting An. gambiae s.s and the incidence of exophilic An. arabiensis suggest a combination of IRS and long lasting insecticidal nets (LLINs) for this region.

Keywords: Malaria vectors, Transmission risk indices, Species specific PCR, Plasmodium falciparum, Circumsporozoite antigen, Long lasting insecticidal nets, Osun State, Nigeria