Abstract
Dogs inoculated with chick-embryo-adapted live distemper virus vaccine was involved in spontaneous apparent infection of distemper.
Clinically, they manifested fever of two-peak type, depression, inappetence, discharge from the eyes and nose, coughing, and sneezing. Pathologically, they exhibited degenerative and hyperplastic changes of lymphatic reticular tissue, broncho-pneumonia, catarrh of the digestive tract, activation of the reticulo-endothelial system in various organs, and encephalitis, although there were variations among them. In addition, cytoplasmic and nuclear inclusion bodies were present in epithelial cells of the bronchi, pulmonary alveoli, urinary bladder, pelvis of the kidney, biliary ducts, pancreatic ducts, and alimentary canal, as well as the glandular cells of the pancreas and neuroglia cells. Moreover, demonstration of virus was positive in the brain, liver, and spleen of a hamster inocula.- ted with infected material. Detection of neutralizing antibody was also positive. As a result, a positive diagnosis of distemper was made in these vaccinated dogs.
Furthermore, the source of supply of these dogs involved and the results of virological studies on them made it possible to assume that the etiological virus had not been derived from the chickembryo- adapted vaccine inoculated but was “street” virus which had infected the dogs before they received the vaccine.
Some discussion was additionally made on the risk which would be met in inoculation experiments with dogs of unknown origin of supply and in inoculation of such dogs with live vaccine.
