Prevalence of endemic Bancroftian filariasis in the high altitude region of south-eastern Nigeria

Abstract

Background & objectives: The study was aimed at determining the prevalence and intensity of Wuchereriabancrofti microfilaraemia in a high altitude region of south-eastern Nigeria, and ascertaining the prevalenceof clinical signs and symptoms associated with the filarial infections.Methods: Thick smear of 50 l finger-prick blood collected at night between 2200 and 0200 hrs from consentingpersons were stained with Giemsa and examined microscopically in a cross-sectional study. Consentingindividuals were examined for various gradations of hydrocele, limb and scrotal elephantiasis by qualifiedmedical personnel.Results: The prevalence of W. bancrofti microfilaraemia was 4.3%, highest in the older people but comparablein both sexes. The overall microfilarial (mf) geometric mean intensity (GMI) among mf positive individualswas 123 mf/ml of blood (138 mf/ml for males and 110 mf/ml of blood for females); and rose significantly withincreasing age (one-way analysis of variance; p < 0.001). Prevalence of clinical manifestations was: hydrocele(7.1%), scrotal elephantiasis (4%), and limb elephantiasis (6%). The mf GMI was significantly higher amongthose without hydrocele or limb elephantiasis than among those with the clinical manifestations (t-test;p <0.05 for both tests); the opposite was the case for scrotal elephantiasis, (t-test; p <0.01).Conclusion: Filariasis is endemic in the high altitude region of south-eastern Nigeria. The chronic clinicalmanifestations observed there underscore the need for urgent combination therapy interventions.

Keywords

• Elephantiasis
• filariasis
• hydrocele
• Nigeria
• Wuchereria bancroft