Experimental inoculation of conventional pigs with tissue homogenates from pigs with post-weaning multisystemic...

This report describes the experimental inoculation of conventional pigs with a tissue homogenate obtained from two pigs affected with postweaning multisystemic wasting syndrome (PMWS). Eight 2-month-old pigs were inoculated by the intranasal route, and two pigs were left as uninfected controls. Clinical signs, rectal temperatures and body weights were recorded. Pigs were necropsied at days 14 or 21 post-inoculation, and tissue samples were taken for histopathology and porcine circovirus (PCV) in-situ hybridization. Although only mild clinical signs of disease were observed, lesions of PMWS were seen, and PCV was shown to have been successfully transmitted to six of the eight pigs. Seroconversion of all inoculated pigs to PCV-2, but not to PCV-1, was also detected, suggesting that the PCV nucleic acid detected by in-situ hybridization in inoculated pigs corresponded to PCV-2. In conclusion, this report shows that PCV-2 is transmissible to pigs, and the inoculation of tissue homogenates containing the virus results in the development of PMWS-like lesions.