Rural bancroftian filariasis in north-western Cameroon: parasitological and clinical studies.

ABSTRACT

A cross-sectional epidemiological, parasitological and clinical survey of bancroftian filarieasis was conducted in the rural north-western Republic of Cameroon. Of the 1020 respondents (622 males and 398 females) randomly drawn from 4 ethnically homogeneous communities, 148 were microfilaraemic giving an overall prevalence of 14.5%. Association between the ages of individuals and the prevalence of microfilaria (mf) in peripheral circulation was statistically significant (chi 2(6) = 12.59, P < 0.05). More males (7.8%) than females (6.7%) of all ages exhibited mf and was significant statistically (chi 2 = 0.98, P < 0.01). Community-specific prevalence of mf ranged from 11.9% in Bambui to 17.0% in Bambeli. At the community level the overall geometric mean intensity (GMI) of infection was 192 mf per 10 ml of blood (range 165 mf p ml to 248 mf p ml). Overt clinical manifestations of chyluria, elephantiasis and hydrocele were detected among the mf-positive respondents. Thirty one cases (20.9%) involving 15 (18.6%) males and 16 (23.15%) females exhibited chyluria which was absent in children aged 1 < or = 10 years but appeared to be associated with advancing age. Elephantiasis especially of lower extremities and breast was observed in 8 (10.0%) males and 15 (22.0%) females. Highest cases of elephantiasis were recorded for female adults aged 41-60 years (34.6%) of total cases. Hydrocele affected 20.0% of mf-positive males ages > or = 11 years with cases increasing with advancing age. A positive association seems to exist between hydrocele prevalence and the prevalence of microfilaraemia. A total of 1440 female mosquitoes belonging to 3 species were dissected for the presence of microfilariae. Anopheles gambiae complex s.l. was the dominant species and the only one found to be naturally infected with mf. The apparently low mf. intensity in the population, pattern of microfilaraemia, distribution of clinical syndromes and vector species are discussed.