Sporadic onchocerciasis in the lower Imo River basin, Nigeria

Abstract

Onchocerca volvulus is present in the Lower Imo River Basin with a mf prevalence of 3.5%,. Microfilaraemia was higher among older than younger individuals and there was no significant difference in prevalence between sexes. Microfilarial intensities varied significantly between sexes and also between age groups. On the overall, prevalence of clinical onchocerciasis was higher than prevalence of microfilaraemia. The commonest clinical manifestation related to O. Volvulus was permanent itching, and visual acuity problem. A total of 42 (48.8%) of the individuals with permanent itching were positive for O. volvulus microfilaraemia. The difference mf prevalence between the two categories was not statistically significant (χ²-test; p < 0.001). The mf GMI of those without permanent itching (24 mf/skin snip) was slightly higher than the mf GMI of those with permanent itching (21 mf/skin snip) but the difference was not statistically significant (χ²-test; p > 0.05). The O. volvulus microfilaraemia was higher among those who presented visual acuity problems with an mf prevalence of 11.9% and an mf GMI of 27 mf/skin snip. For those who did not present with visual acuity problems, 2.5% were positive for O. volvulus microfilaraemia, with an mf GMI of 19 mf/skin snip. The difference in mf prevalence was statistically significant (γ ²-test; p < 0.01); and the difference in mf GMI was also statistically significant (t-test; p <0.001).



AJAZEB Vol. 6 2004: pp. 66-70