Experimental canine parvovirus infection in dogs.

In specific pathogen-free dogs, clinical signs of experimental canine parvovirus infection were mild, inconsistent and transient. Clinical signs were more pronounced in conventionally-raised dogs, but the severe disease reported in field cases was not reproduced in either group. A pronounced plasma viremia occurred on the 2nd to 4th day post-infection (d.p.i.) in dogs challenged oronasally. Antibody was detectable on the 5th d.p.i. Marked pyrexia was rare, but a significant temperature rise usually coincided with the appearance of antibody and the cessation of viremia. Significant lymphopenia, but not leukopenia, occurred on the 3rd to 7th d.p.i. Virus could be readily isolated from fecal matter on the 3rd to 8th d.p.i.; a few dogs continued to shed virus for up to 12 days. In dogs challenged parenterally, the onset of elevated temperatures, viral shed and antibody production occurred 24-48 hours sooner. Convalescent dogs were no longer contagious for susceptible contact animals 25 days or longer after challenge, although infectious virus persisted in feces for more than 6 months at room temperature. Active giardiasis seemed to exacerbate the clinical syndrome, although treatment with corticosteroids or anti-thymocyte serum did not.