The Climate of North-central Nigeria and Potential Influence on Mosquito (Diptera: Culicidae) Vectorial Capacity, for Disease Transmission

Abstract

The overwhelming disproportionate burdens of mosquito-borne diseases recorded in the Tropics have been attributed, to a large extent, to the prevailing clement climatic conditions for enhanced mosquito vector population development and parasite embryogeny. Yet, spatial heterogeneity in tropical climatic conditions abound, and the exact inter-play between weather conditions and mosquito ecology is not well understood in different tropical localities. This study, therefore, established the climatic status of North-central Nigeria, and elucidated the potential influence of prevailing weather conditions on mosquito vectorial capacity in the area. Methodology: Minna, an ecological setting that represents the general ecotype of North-central Nigeria was selected for data collection. Meteorological data of rainfall, relative humidity and temperatures, spanning periods variously ranging from 1985 – 2010, were obtained from standard weather stations in the area. Collected data were processed and analyzed for mean monthly and annual values for each climatic variable. Results: The results indicated mean cumulative annual and monthly rainfall in North-central Nigeria to be 1247.52±166.68mm and 103.96mm, respectively. Mean annual temperatures in the area were 22.55±0.42oC minimum, and maximum of 33.54±0.23oC. Mean annual relative humidity was barely above 50%, and varied within narrow limits (range = 50.08 – 52.75%). Monthly rainfall distribution extends from May through October, with a unimodal peak in August (274.23mm). The months of January and February were completely rainless while months of very little rainfall were recorded in April and November, respectively, regarded as pre- and post-rainy season transition periods. Interpretation/Conclusion: The results clearly confirmed the climate of North-central Nigeria to be tropical and of the dry grassland Savanna type. However, while the amounts and distribution of rainfall as well as, temperatures of the area are such that, respectively, promote rapid mosquito population development and parasite maturation; the relative humidity appears limiting to mosquito survival.