Spatial Distribution of Mosquito Vectors in Relation to Physico-chemical Properties of the Breeding Habitats in Ondo State, Nigeria; A Sign for Mosquito Borne Diseases

Abstract

The abundance and distribution of identified mosquito genera in Ifedore Local Government Area of Ondo State, were studied. Mosquito species were sampled from 3sites per settlement using 200 ml plastic dippers (maximum of 10 dips per site) and collection containers. The habitats sampled included containers, stagnant pools, domestic run-offs, foot and vehicle prints, tyres, and gutters. The larvae and pupae collected were reared to adulthood and preserved in silica gels inside 1.5ml Eppendorf tubes and identified morphologically in accordance to standards after which Polymerase Chain Reaction protocol was conducted on all the <i>Anopheles </i>mosquitoes and 156 of the Culex mosquitoes. Larvae were taken from a total 33sites spreading uniformly across the 11 towns and villages making the Local Council to have various stages of larvae and pupae. 2051 immatures grew up to adulthood, after morphological identification 6 genera were recorded namely: <i>Anopheles gambiae </i>s.l was 348 (194 males and 154 females) (16.97%), Aedes 394 (248 males and 146 females) (19.11%), <i>Culex </i>was 1270 (740 males and 530 females) (61.97%), <i>Mansonia </i>was 7 (3 males and 9 females) (0.34%) <i>Toxorhynchite </i>was 20 (14 males and 8 females) (1.07%) and <i>Coquillettidia </i>was 12 (3 males and 9 females) 0.59%. The 1270 <i>Culex species </i>were further identified as <i>Culex pipiens </i>complex 1136 (89.45%) and <i>Culex tigripes </i>134 (10.55%). After molecular analyses <i>Culex pipiens quinquefasciatus </i>were 154 (98.72%) while After PCR identification of all the 348 <i>Anopheles gambiae </i>s.l spoilt 8 (2.30%), <i>Anopheles arabiensis </i>21 (6.05%), <i>Anopheles gambiae </i>s.s was 315 (90.52%), <i>Anopheles merus </i>4 (1.15%) while the remaining were spoilt. This study concludes that the residents of the areas are at risk of mosquito-borne diseases most especially malaria whose vector is recorded specifically in the research. The results obtained of this study showed composition in mosquito species present at the study area. This research advocates proper environmental monitoring and source reduction of the breeding sites as the presence of these species also showed that this environment is predisposed to mosquito borne diseases.