No abstract

No abstract

In Nigeria infection with onchocerciasis has been under control with the introduction of ivermectin in most affected communities for a decade. To assist ‘stop mass drug administration (MDA)’ decision, a cross-sectional survey evaluated the impact of ivermectin on onchocercal Skin Diseases (manifestations) from 540 participants in 5 endemic communities. The rapid epidemiological assessment (REA) method with palpable nodules and skin depigmentation (leopard skin, LS) as diagnostic indices were used. The prevalence profiles of palpable nodules and leopard skin was 5.9% and 12.2% respectively. Prevalence of clinical features varied among the farming community (P<0.05). Similarly, age group 21-30 years had significant prevalence of clinical features than other age groups (P<0.05).  Males had significantly higher prevalence of these indices (palpable nodules 6.8(%; LS 13.3%) than females (palpable nodules 4.6%; LS 11.1%). Although, Onchocercal Skin Diseases (clinical manifestations) were observed in all age groups, it occurred most in older groups. These groups with nodules could portend as reservoir for transmission. The implications of the results were discussed in the context of the on-going prediction of possible elimination of onchocerciasis in Africa and ‘stop MDA’ decision.

No abstract

Bancroftian filariasis in Nigeria is endemic with 22.1% of the population thought to be infected. The main mosquito genera implicated with Wuchereria bancrofti transmission are Anopheles and Culex. The study was carried out to compare the infectivity rates of the vectors between the high transmission (rainy) and the low transmission (dry) seasons. Mosquitoes were sampled from houses and compared from six sentinel villages (3 each from Ohaukwu and Abakiliki Local Government Areas) of Ebonyi State, Nigeria. Day resting indoor collection (DRI) by Aspirator and Pyrethrum Spray Catch (PSC) were used to collect mosquitoes between 7:00 and 11:00am. After morphological identification, female parous mosquitoes were dissected in search for infective (L 3) larvae of W. bancrofti. A total of 4,840 female mosquitoes were dissected. More mosquitoes were caught in the rainy season than in the dry season. Infectivity rates of vectors in Ohaukwu villages were 3.54 and 5.41% in the rainy and dry seasons, respectively, whereas in Abakiliki villages these were 1.85 and 1.19%, respectively. There was no significant difference in the overall infectivity rates between the two seasons in both Ohaukwu and Abakiliki villages (p>0.05). Similarly, no significant difference in the total/average transmission potentials were found between the seasons (p>0.05). Anopheles gambiae sl was the main vector in both study sites followed by an Anopheles funestus and Culex quinquefasciatus. There was a difference in infectivity rates of Anopheles species between the wet and dry seasons (p<0.05), whereas no significant difference exist in infectivity rates of Anopheles species and Cx. quinquefasciatus (p>0.05). Findings were discussed in the context of ongoing plans to eliminate filariasis and the transmitting vectors.