Outbreak of neonatal canine herpesvirus infection in a specific pathogen-free beagle colony.

Nine out of 19 newborn pups from 4 litters died or euthanatized on day 10 to 17 after birth in a specific-pathogen-free beagle colony which had been established by cesarean section and bottle-feeding. Necropsy showed congestion and edema of the lungs, congestion of the liver and splenomegaly, as well as many subcapsular petechiae and wedge-shaped areas of ecchymosis on the cut surface of the kidneys. A cytopathic agent isolated from the lungs, kidneys and liver was identified as a canine herpesvirus. The bitches in the animal house were seroconverted into positive for the isolate after the outbreak of the disease. Histopathological lesions in six cases were characterized by multiple necrosis and hemorrhage in various organs. In addition, fibrinoid necrosis was seen in the arterial walls in wedge-shaped necrotic areas of the kidneys. The outbreak appeared to be temporary, since the same disease has not occurred in the colony up to the present time.