Molecular characterization of spatially heterogeneous populations of the malaria vector (Anopheles gambiae s.l) in Niger State, Nigeria

Abstract

In this study, Anopheles mosquitoes were characterized through an investigation of adult female mosquitoes for sibling species. For the first time, researchers combined efforts on morphology and DNA barcoding utilizing the markers cytochrome c oxidase subunit I (COI) gene and internal transcribed spacer 2 (ITS2) region was made. Cytochrome c oxidase subunit I and ITS2 regions of morphologically differentiated, Anopheline mosquitoes were sequenced. According to the results of molecular identification (PCR) of the distinctive sibling species of the Anopheline mosquitoes, two sibling species from An. gambiae complex and An. rufipes group were identified viz; An. gambiae ss (Giles 1902) and An. rufipes (Gough 1910), these sibling species were discovered in Bosso LGA's Large water and Gutter. An. gambiae s.s was collected in all the breeding habitats sampled in Katcha, Lapai and Shiroro LGAs. In this report, the habitat breeding density of the An. gambiae s.s. was found to be higher compared to An. rufipes, which was restricted to large water and gutter breeding habitats. This study highlights the usefulness and feasibility of COI and ITS2 genetic markers in recognizing Anophelines, their sibling species, the importance of a unified, systematic approach in mosquito taxonomy and highlights the epidemiological role of An. gambiae s.s. For the first time in Niger State An. rufipes has appeared as a malaria vector, emphasising the need for proper monitoring of this species across the country to effectively set up vector management strategies.