Porcine circovirus is being blamed for a disease syndrome in Ontario grower-finisher barns, where mortality rates of five to 20 per cent or higher are being recorded. Dr. Robert Friendship, a Professor in the Department of Population Medicine at the University of Guelph, has responded
to this outbreak by conducting a case-control study designed to observe 25 farms with a history of clinical Porcine Circovirus type 2 (PCV2) disease and 25 matched farms that have not been diagnosed with PCV2. Friendship, who has been involved in survey studies examining the prevalence of
the problem, estimates that the disease affects about a quarter of grower-finisher operations in Ontario and appears to be spreading. PCV2 was identified as a possible cause of disease
in pigs in the early 1990s by swine veterinarians in Western Canada and was later discovered in all pigs worldwide.