Rapid epidemiological mapping of onchocerciasis in areas of Uganda where Simulium neavei sl is the vector

Objective: To test whether Rapid Epidemiological Mapping of Onchocerciasis (REMO) was suitable for mapping of onchocerciasis in foci where S.neavei sl is the primary vector. Design: Topographical maps of scale 1:250,000 were used in demarcating regi ons into ecotopographic divisions and zones in order to identify potential onchocerciasis endemic areas. Setting: The study was conducted in Kabarole and Nebbi districts. High-risk communities were selected 30 km from each other, and closest to rivers whe re vector breeding appeared likely. Secondary and additional communities we re selected 10 km and 20 km away from high-risk communities, respectively. Subjects or participants: Communities were mobilised for nodule palpation. A sample of thirty males aged at least 20 years, from each community that h ad lived in the area for at least ten years, were randomly selected and exa mined. Interventions: Individuals positive for at least one nodule were expressed in terms of Nodule Prevalence Rates (NPR) which were used to map the distri bution of onchocerciasis. Main outcome measures: Coefficient of variation (CV) of Nodule Prevalence R ates between high risk secondary communities. Results: In Kabarole district, the results indicated a low coefficient of v ariation (CV) of 75 in NPR between high risk and secondary communities whil e in Nebbi district, higher CV of 187.4 was attained. The less varied NPR i mplies that communities in Kabarole were almost equally exposed to onchocer ciasis while highly varied situation in Nebbi indicated decreasing NPR with increasing distance from high-risk communities. Conclusion: REMO is applicable in areas where S.neavei sl is the primary ve ctor, for identification and mapping communities requiring mass treatment w ith ivermectin.