Aedes (Stegomyia) Mosquitoes in the Ashanti Region of Ghana: Implications for Yellow Fever Paucity

Abstract

A research was carried out to map Aedes mosquito vectors of Yellow Fever (YF) in 4 localities (KNUST, Ejisu, Angola and Akropong) in the Ashanti Region of Ghana to identify and catalogue the various species of Aedes mosquitoes that may occur in the Region. This is to ascertain possible factors (both physical and biological) that may influence the population densities of Aedes mosquitoes and the possible reasons for the paucity of YF in the Region. Several species of Aedes mosquitoes were encountered and identified. Of all the mosquito species identified, Aedes aegypti was the predominant (81%). This was followed by Aedes vittatus (3.3%) and Toxorhynchites brevipalpis (3.1%). The bulk of the other mosquitoes apart from Aedes and Toxorhynchites brevipalpis was only 9.5%.  The research analyzed the output of elliptical profile model generated for 4 Aedes vectors (n=2,7492) and 4 sample locations. Analysis of the model output  reveals that the standard deviational ellipse is significantly better able to predict the linear distribution of Aedes populations within the geographical region. The relationship between the orientation of the elliptical profiles and the mean linear orientation of the corresponding quarters was assessed to reveal a moderate but significant association.  These findings demonstrate that the sample locations vis-à-vis pH concentration impact on the distributions of Aedes within the geographical area and supports the ecological variability within the sample locations.

Keywords: Yellow Fever, Aedes mosquitoes, Toxorhynchites brevipalpis,  pH Range, GIS