Circovirus Infection in Underdeveloped Pigs

Abstract

Beginning in June 1997, in a hoggery under our jurisdiction, on a farm in Toyama Prefecture, we began occasionally finding major clinical signs of poor growth in some young weaned pigs. This condition was sometimes accompanied by pale skin, loss of vigor, and diarrhea. Histopathological examinations revealed lymphadenopathy, hypolymphemia, and basophilic inclusion bodies in reticuloendothelial cells in the affected pigs. Electron microscopy detected circovirus-like particles in the inclusion bodies. These clinical and pathological findings resemble those observed in cases of post weaning multisystemic wasting syndrome (PMWS). The DNA sequence of PCR products from the pigs' lymph node emulsions showed a homology higher than 96.9% to the circovirus suspected of being the PMWS causal factor (pmws-PCV). These results suggest that the pmws-PCV is involved in the disease of the young pigs.