Microhabitat Assessment of the Breeding Sites of Simulium damnosum Theobald Complex in Oji River Basin, Enugu State Nigeria

Abstract

Aims: Blackflies of the Simulium damnosum complex are the principal vectors of Onchocerca volvulus, the causative agent of Onchocerciasis (river blindness) in Nigeria and other West African countries. They therefore constitute serious public health and socio-economic problems in the areas that they occur. The study was undertaken to assess some physical and chemical factors affecting the distribution of Simulium damnosum complex in Oji river basin, Enugu state, Nigeria. Study Design: Larval prospection was carried out in eleven riverine breeding sites in Oji river basin and physico-chemical parameters these breeding sites were evaluated. Place and Duration of Study: A one year study was carried out between December 2011 and November 2012 in four communities in Oji river Local Government Area, Enugu state. Methodology: Physical and chemical parameters of the breeding sites such as water temperature, velocity, turbidity and pH were determined. Measurements were taken between 10:00 and 11:00 hours local time on each visit. The features of the sites were also assessed by visual observation and scored as either presence or absence of rocks, logs and trailing vegetation and presence or absence of human and animal activities. Results: A total of two hundred and ninety-one (291) S. damnosum complex larvae were collected. Of the microhabitat characteristics measured, water velocity and turbidity (P<0.05) were the only parameters showing significance with the distribution of S. damnosum complex larvae at the breeding sites. Conclusion: This study provides information on prevailing microhabitat characteristics of breeding habitats of S. damnosum s.l., which may have implications in predicting vector distribution and disease transmission. This knowledge is crucial for accurate planning of onchocerciasis elimination programs.