Species composition of the Anopheles gambiae complex across eco-vegetational zones in Bayelsa State, Niger Delta region, Nigeria.

Background & objectives: Correct vector identification is an important task in the planning and implementation of malaria vector control programmes. This study was designed to provide baseline information on the species composition and distribution of members of the Anopheles gambiae complex in three eco-vegetational zones in Bayelsa state, Nigeria. Methods: Adult mosquitoes were collected by pyrethrum spray catch (PSC) in randomly selected houses during September 2009–August 2010. Anopheles mosquitoes were identified using standard morphological keys. Mosquitoes identified as An. gambiae s.l. were used for species specific PCR-assays. Results: Out of 203 Anopheles gambiae s.l. successfully amplified, 180 (88.7%) were Anopheles gambiae s.s., 14 (6.9%) were An. melas and 9 (4.4%) were An. arabiensis. The variation in the sibling species composition of An. gambiae s.l. was not significant (p >0.05). Anopheles gambiae s.s. was predominant in all the collections with three sibling species occurring in all the eco-vegetational zones. Interpretation & conclusion: The observation of An. melas in the fresh water swamp forest of Yenagoa is of importance in malaria epidemiology. These findings are of importance in the planning and implementation of malaria vector control strategy in the three eco-vegetational zones of Bayelsa state.