Epizootology of wildebeest-derived malignant catarrhal fever: possible transmission among cows and their calves in the north-western Transvaal.

The investigation involved 52 cases of wildebeest-derived malignant catarrhal fever in 1986 and 1989 in a herd of cattle kept in camps adjacent to a game farm harbouring a herd of approximately 330 blue wildebeest (Connochaetes taurinus). In the outbreaks, 34 cows and 18 calves died as result of the disease. The exceptionally high incidence of the disease in both cows and their calves, the low incidence in calves of unaffected cows, the relatively short period between the death of cows and their calves as well as the occurrence of the disease in 2 calves born after their mothers had been moved away from wildebeest, are indicative of transmission among cows and calves. The death of at least 6 calves within 6 weeks of birth is ascribed to intra-uterine infection while some calves that survived longer may have acquired the infection from other cattle or from wildebeest.