The interplay between malaria vector population, seasons, and malaria prevalence

Abstract

A retrospective scrutiny of dataset from a semi-longitudinal investigation reveals a dynamic interaction between seasons, vector population density and malaria prevalence. Indoor resting mosquitoes collected between the hours of 06:00 and 09:00 using Pyrethrum Spray Catch (PSC), were preserved dry over silica gel and used for morphological and molecular identification. Asymptomatic malaria prevalence was determined through Rapid Diagnostic Test (RDT), Microscopy test and PCR. A line list hospital attendance record was collated to explore the symptomatic malaria situation. Metrological data was collected from a weather station in the study community to see impact of some weather elements on the malaria situation. The four seasons under study shows a progressive increase in vector population density with increase in rainfall. A strong positive correlation exists between vector population and asymptomatic malaria prevalence [PCRtest-R2=0.439(43.9%); RDT+MicroT -R2=0.425(42.5%); RDT- R2=0.342(34.2%)]. Symptomatic malaria peaked during the dry season (12.54%) with lower vector density while onset of rains with higher vector density recorded the least (4.7%). Established here is a dynamic interaction between malaria vector population, prevalence and the environmental landscape; hence the imperative for an ecological input in the face of fluctuating climatic elements.