Malaria Vectors Composition, Abundance And Prevalence Of Malaria In Potentially High Endemic Area Of Morogoro Rural District, Eastern Tanzania

ABSTRACT

This dissertation was prepared based on “publishable manuscripts” format of the Sokoine

University of Agriculture. The dissertation discusses the composition and seasonal

abundance of malaria vector species and disease prevalence in potentially high endemic

foci in Morogoro region. Well targeted efforts that embrace area-specific situations, at

least in high malaria endemic foci, are needed to preserve realized health gains and

achieve elimination. This is because malaria is increasingly characterized by temporal

variability that bestows evolving and new challenges for malaria control programs.

Morogoro region, eastern Tanzania is a typical reflection of such phenomenon because of

its appreciable fine-scale variability in ecology and topography. Therefore, it is likely that

we are missing certain salient foci with unprecedented malaria transmission intensity. It

was therefore critical to have up-to-date information on the species composition and

abundance of malaria vectors; and disease prevalence in order to design and/or implement

appropriate surveillance and control strategies. Mkuyuni and Kiroka, adjacent wards

within Rural Morogoro District, are purported to form such foci and were therefore the

focus of this study. The determination of malaria vector species composition and seasonal

abundance was achieved through a repeated cross-sectional survey conducted during the

wet and dry season. It involved collection of adult mosquitoes inside 10 randomly

selected households and adjacent outdoor points using CDC light traps. This was

accompanied by the assessment of environmental risk factors which could be potentiating

malaria transmission risk. The prevalence of malaria in the study area was determined

through a retrospective analysis of six-year (2014 - 2019) data on malaria cases. This

study indicated that malaria vector population in study areas is largely composed of An.

gambiae s.l followed by An. funestus s.l.; and their abundance is equally concerning

across seasons. The study also revealed high malaria intensity in the study areas, with

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prevalence rate as high as ~61%. The mosquito species composition and equally

concerning seasonal abundance all year round along with risk factors like open eaves,

proximity to rice fields and low usage of bed nets could be among the factors that

underline high malaria transmission in the study areas. These preliminary findings

warrant more comprehensive longitudinal study in these and other high endemic foci in

Tanzania in order to inform future course of action in terms of disease surveillance and

control.

Keywords: Malaria, mosquito composition, abundance, malaria prevalence, Mkuyuni,

Kiroka