Evidence of onchocerciasis in Georgia cattle: longitudinal survey of a small herd.

Between November, 1974, and March, 1976, skin biopsies were taken at 12 different times from a small herd of 8 to 10 cattle near Lawrenceville, Ga. Samples were incubated for 4 to 6 hours in Hanks' balanced salt solution and centrifuged, and the sediment was examined microscopically for microfilariae. Microfilariae were consistently found in 4 of 10 animals over a 12-month period; numbers of microfilariae ranged from 1 to 211, with a mean of 3.42, 12.89, 17.31, and 27.53 per 4-mm-diameter biopsy from the 4 individual animals. The parasite was evidently being transmitted on the farm, as evidenced by the presence of microfilariae in an animal born on the farm.