The Effect of Climatic Factors on the Distribution and Abundance of Mosquito Vectors in Ekiti State

Abstract

In warm and tropical climatic regions of the world, climatic factors have been associated with relative mosquito abundance and transmission of mosquito borne infections. The main objective of this study is to assess the change in seasonal abundance and distribution of mosquito vectors in relation to climate variables (rainfall, temperature and humidity). Mosquito samples were collected from randomly selected houses in all the Local Government Areas of the State using Aspirators, light trap and pyrethrum spray catch methods from July 2006 to June 2008. Species of Anopheles, Aedes and Culex mosquitoes were collected. Anopheles gambiae s.s had the highest number (43.5%) out the three malaria vectors found. For Aedes and Culex species collected, Aedes aegypti (37.6%) and Culex fatigans (37.1%) have the highest prevalence out of their sibling species. Temperature and Rainfall were highly correlated with the abundance of mosquito vectors. It was observed that relative humidity of at least 50- 55% prolong mosquito survival. The rainy season (March to October) recorded the highest number of mosquito vectors collection with the peak in the months of July and August while the lowest collection was in the month of February when there was little or no rains. The environmental and ecological factors including Human activities enhanced the breeding and abundance of these mosquito vectors.

Keywords:  Culex fatigans; Aedes aegypti; Mosquito; rainfall; temperature; abundance