Response of conventionally raised weanling pigs to experimental infection with a virulent strain of porcine parvovirus.

Conventionally raised 6-week-old pigs were inoculated intranaslly and orally with porcine parvovirus. The pigs remained clinically normal for up to 17 days. They were viremic between 2 and 6 days after inoculation and had detectable hemagglutination-inhibiting titers to porcine parvovirus at 5 or 6 days after inoculation. Virus was isolated from multiple tissues of pigs killed between 3 and 17 days after inoculation. Viral antigen was demonstrated mainly in lymphoid tissues of these pigs. Gross and microscopic examination of tissues failed to reveal any notable pathologic changes. The numbers of thymus- and bone marrow-derived lymphocytes did not differ significantly in inoculated and noninoculated control pigs, and the response of peripheral blood lymphocytes to selected mitogens was not altered by infection.