Effect of bendiocarb based (Ficam® 80% WP) Indoor Residual Spraying on feeding patterns of malaria vectors in Burkina Faso, West Africa.

Abstract Background : Vector control is a key component in malaria prevention strategies in many malaria endemic countries in Africa. In Burkina Faso, malaria transmission is seasonal in most parts of country, so a single round of spraying should provide effective protection against malaria, provided the insecticide remains effective over the entire malaria transmission season. The primary effects of IRS towards curtailing malaria transmission are : i) to reduce the life span of vector mosquitoes and ii) to reduce the density of the vector mosquitoes. Methods : CDC light trap and pyrethrum spray catches were carried out monthly to determine the change in malaria vector indices in sprayed (Diebougou) and unsprayed sites (Dano). The females malaria vectors collected by CDC light trap and PSC were used to determine their blood feeding and sporozoites rate using enzyme-linked immunosorbent assay (ELISA) and their biting rate and entomological inoculation rateResults: Three species belonging to the Anopheles gambiae complex (Anopheles gambiae s.s., Anopheles coluzzii and Anopheles arabiensis) are present throughout the transmission season, but An. gambiae s.s.was the most frequent species of the complex (P =0.0005), comprising 88% of the total collected and the most infected species. Malaria vectors densities were significantly lower in sprayed villages (n=4,303) compared with unsprayed villages (n=12,569) during post-spraying period (P = 0.0012). In addition, mean human biting rate of An. gambiae sl and An. funestus ss were significantly lower in sprayed areas compared to unsprayed areas (P<0.05). Overall, malaria vector transmission risk was significant lower in villages which received IRS (P=0.0001) whatever the malaria vectors species (An. gambiae sl and An. funestus ss).Conclusion: The results showed that in the sprayed area (Diebougou), vector densities, human biting rates and malaria transmission risks were very lower than unsprayed areas (Dano). The findings also showed a change in vector behavior especially within An. funestus which became more zoophagic following IRS. The indoor residual spraying could be recommanded as control tool in areas where malaria transmission occured throughout the year.Keywords: Indoor residual spraying, bendiocarb, malaria vectors, mosquito feeding patterns, Burkina Faso.