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

BACKGROUND & OBJECTIVES The study was aimed at determining the prevalence and intensity of Wuchereria bancrofti microfilaraemia in a high altitude region of south-eastern Nigeria, and ascertaining the prevalence of clinical signs and symptoms associated with the filarial infections. METHODS Thick smear of 50 μl finger-prick blood collected at night between 2200 and 0200 hrs from consenting persons were stained with Giemsa and examined microscopically in a cross-sectional study. Consenting individuals were examined for various gradations of hydrocele, limb and scrotal elephantiasis by qualified medical personnel. RESULTS The prevalence of W. bancrofti microfilaraemia was 4.3%, highest in the older people but comparable in both sexes. The overall micro filarial (mf) geometric mean intensity (GMI) among mf positive individuals was 123 mf/ml of blood (138 mf/ml for males and 110 mf/ml of blood for females); and rose significantly with increasing 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 among those 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 clinical manifestations observed there underscore the need for urgent combination therapy interventions.