Scrotal onchocerciasis in a bull in Nigeria.

SUMMARY During an abattoir survey of the pathological conditions of the scrotum and its contents in bulls, onchocerciasis was observed in one bull. On account of its peculiar location in the scrotum and the small size of the microfilariae (mean length 153·2 ± 35·4 microns) it was tentatively identified as Onchocerca ochengi . The adults rather than the microfilariae provoked the main tissue reaction.