The prevalence, gross lesions and histopathology of aortic onchocerciasis in Nigerian cattle.

The incidence of aortic onchocerciasis due to Onchocerca armillata among slaughtered cattle in Ibadan, Nigeria, was about 2 per cent between 1979 and 1980. The average number of nodules per thoracic aorta was 7 and the mean size of each nodule was 9.7 +/- 2.6 mm. About 54 per cent of the nodules examined were calcified, and nodular calcification appeared to be related to the degree of infection or reinfection with the parasite. The histopathology of the aortic lesions is described.