OTTAWA - The Canadian Food Inspection Agency says it hasn't been able to confirm a link between a deadly pig virus and feed pellets containing hog blood plasma.

Cases of the virus, known as porcine epidemic diarrhea, have been confirmed in Quebec, Ontario, Prince Edward Island, and Manitoba.

Last month, the inspection agency said it was looking at the possibility that the virus may be found in U.S. origin porcine blood plasma used in feed pellets produced by Ontario-based Grand Valley Fortifiers.

Its studies found that while the blood plasma itself contained the virus capable of causing disease in pigs, tests could not show that the feed pellets containing the plasma were capable of causing disease.

The agency says it will continue to analyse feed and feed ingredients to protect Canadian livestock.

The highly contagious virus, which originated in China and killed millions of piglets in the United States, is unique to pigs and officials say it poses no threat to humans.