title: Epidemiological studies of onchocerciasis in forest villages of Sierra Leone.
abstract: Results are presented for five villages in the forest zone of Sierra Leone in which forest onchocerciasis was considered to be a significant health problem. All five villages were found to be hyperendemic and 85% (682/803) of persons were found to have at least one sign of onchocerciasis. The emergence of microfilariae from skin snips (iliac crest and/or canthus) or the presence of nodules accounted for 96.5% of all persons positive for onchocerciasis. The prevalence of nodules from all body sites was 70.5% and of elephantiasis, hanging groin and skin lesions (moderate and severe) was 0.4%, 0.3% and 5.3% respectively. Analysis of eye lesions (the most serious clinical manifestation of the disease) was restricted to persons aged 30 years and over since this gives a better indication of the public health importance of onchocerciasis than analysis in the overall population. This gave prevalence rates of onchocercal blindness of 4.5% (both eyes) and 2.8% (one eye only). Rates for the four potentially blinding eye lesions were sclerosing keratitis (4.1%), iritis (16.5%), optic atrophy (13.8%) and choroidoretinitis (14.4%). Rates in males were approximately twice as high as those in females.
authors.affiliation: MRC Laboratory, Bo, Sierra Leone.
authors.forename: J E
authors.initials: JE
authors.lastname: McMahon
authors.forename: S C
authors.initials: SC
authors.lastname: Sowa
authors.forename: G H
authors.initials: GH
authors.lastname: Maude
authors.forename: C M
authors.initials: CM
authors.lastname: Hudson
authors.forename: B R
authors.initials: BR
authors.lastname: Kirkwood
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000818:Animals; D001766:Blindness / Q000453:epidemiology / Q000209:etiology; D002648:Child; D002675:Child, Preschool; D002825:Chorioretinitis / Q000453:epidemiology / Q000209:etiology; D005260:Female; D006801:Humans; D007634:Keratitis / Q000453:epidemiology / Q000209:etiology; D008297:Male; D008875:Middle Aged; D009854:Onchocerca / Q000302:isolation & purification; D009855:Onchocerciasis / Q000453:epidemiology* / Q000635:transmission; D009896:Optic Atrophy / Q000453:epidemiology / Q000209:etiology; D012424:Rural Population; D012737:Sex Factors; D012807:Sierra Leone; D012867:Skin / Q000469:parasitology