Current status of bancroftian filariasis in rural communities of the lower cross river basin,Nigeria: parasitological and clinical aspects

Background and objectives  There is a dearth of information on the geographical distribution of bancroftian filariasis in Africa on which to establish elimination programmes. The aim of this study is to assess the prevalence and density of microfilaraemia and the prevalence of clinical manifestations of bancroftian filariasis in six rural communities of Lower Cross River Basin, Nigeria. Methods  A total of 829 finger prick blood smear samples were collected from volunteers between 22.00 and 02.00 h and were examined for presence of helminth parasite Wuchereria bancrofti using standard parasitological method of diagnosis. All the volunteers were also screened for clinical manifestations of lymphatic filariasis. Results  Forty-six (5.6%) of the 829 samples collected were found to be microscopically positive for W. bancrofti. The prevalence of microfilaraemia was significantly (P<0.05) higher in females (8.4%) than males (3.6%). There is a significant variation (P<0.05) in the age-specific prevalence, with the age group 41–60 years being the most affected (10.2%). The overall geometric mean microfilarial density of the infected persons was 9 mf/50 μl. It was higher in males (11 mf/50 μl) than females (7 mf/50 μl) (P>0.05). The prevalence of infection and geometric mean density showed large variations; there was a trend towards increasing prevalence and density with increase in age in both sexes. The overall disease prevalence was 9.2%; the most important clinical manifestation was hydrocele (10.5%) and lymphoedema (2.9%). These chronic disease manifestations increased with age (P<0.05). Conclusion  These baseline data would be useful in planning for the elimination of lymphatic filariasis in Africa as per the WHO goal to eliminate lymphatic filariasis by the year 2020.