Role of species composition in malaria transmission by the Anopheles funestus group (Diptera: Culicidae) in Ghana.

Malaria remains a public health problem in Ghana, with Anopheles gambiae and Anopheles funestus as the predominant vectors. While much information exists on the species composition of An. gambiae, very little exists for An. funestus. This study was carried out to determine the species composition of An. funestus Giles populations from three ecological areas in Ghana and investigate their role in malaria transmission. Mosquitoes were collected using human landing and pyrethrum spray methods. A total of 10,254 Anopheles individuals were collected, out of which An. funestus constituted 53.6% (5,496). An. funestus sensu stricto (s.s.) and Anopheles lessoni were identified as the only members of the An. funestus group in all three ecological areas. All 62 sporozoite positive specimens that were identified as An. funestus s.s. were highly anthropophilic with a human blood index in the range of 80-96%, whereas more than 83% of the An. leesoni had fed on either bovine, goat, or sheep. Malaria transmission was higher in the Sahel savannah area than the rest of the ecological zones, with An. funestus s.s. being implicated as a vector of malaria in all ecological zones. Anopheles leesoni occurred in all the ecological areas but played no role in malaria transmission. The study established the importance of An. funestus s.s. in malaria transmission in Ghana.