Assessments of Onchocerca Volvulus Infection in Humans and Black flies and Onchocerciasis Response to Ivermect in among Villagers around Gurara Dam, Kaduna State, Nigeria

Abstract

Purpose: A study on the assessments of onchocerciasis rates in humans and black flies and its response to ivermectin therapy among villagers around Gurara dam, Kaduna state, Nigeria was conducted between June to November 2016.

Principal methodologies: A total of 158 skin snips were collected and 4994 black flies were caught. The skin snips and female black flies were analysed by means of microscopy to detect Onchocerca volvulus infection. An amplified Polymerase Chain Reaction (PCR) detected O. volvulus DNA from skin snip of some individuals.

Key finding: From the skin snips analysed, 4(2.6%) were positive for Onchocerca volvulus infection. The highest number of flies caught (1274) and highest number of parous flies (1089) were recorded in June. The highest number of infected flies, 14(38%) was obtained in the month of July. The drug Ivermectin, administered in the study population was effective in humans, with 75% complete resolution of symptoms. The highest incidence of Onchocerca volvulus was found among the age group of 50 years and above (75%). The prevalence was higher among the farmers (75%) with equal distribution among females (50%) and males (50%), followed by artisans (25%). The risk factor implicated was regular visit to the dam. The signs and symptoms of onchocerciasis observed were; white patches, severe body itch, nodules and hanging groins.

Conclusion: This study revealed that infective black flies are still hovering around Gurara dam, thus the persistence of onchocerciasis among the inhabitants, especially farmers, of the sampled villages. Hence the call for an effective vector control and a well supervised and prolonged ivermectin distribution