Retrospective serological survey of antibodies to porcine circovirus type 1 and type 2

A retrospective serological survey was performed to determine the presence of antibodies to porcine circovirus type 1 (PCV1) and porcine circovirus ty pe 2 (PCV2) in serum samples collected from sows at slaughterhouses in Cana da in 1985, 1989, and 1997, Each serum sample was tested by indirect immuno fluorescence on PCV-free PK15 cells, on PCV1-infected PK15 cells and on PCV 2-infected PK15 cells. For the 3 years studied, sera positive to PCV1 and P CV2 were identified and the number of sera positive for PCV2 was greater th an the number of sera positive for PCV1. The results indicated 1) that PCV2 appears to be the main PCV type circulating in the Canadian pig population , 2) that PCV2 had been circulating in the Canadian pig population at least 10 years before the postweaning multisystemic wasting syndrome (PMWS) was reported, and 3) that serological evaluation using PCV1 underestimates the seroprevalence of PCV2.