Concurrent outbreak of pseudo-lumpy skin disease and acute Trypanosoma vivax infection in cattle.

Pseudo-lumpy skin disease and acute Trypanosoma vivax infections occurred simultaneously in a dairy herd which had no previous history of trypanosomiasis. The onset of the outbreak was sudden and 29 out of the 40 adult Friesian and exotic x zebu cattle were found to have skin lesions. Five out of the nine animals sampled had fulminating T. vivax parasitaemias with packed red cell volumes ranging from 0.09 to 0.28 litres/litre. Whereas carried tsetse may have introduced T. vivax, the failure to trap tsetse and the presence of large numbers of biting flies strongly suggested that in this outbreak both aetiological agents were transmitted mechanically.