Manitoba's top veterinarian said samples collected from a "high pig-traffic site" have tested positive for the porcine epidemic diarrhea virus.

The province said the samples were found during routine surveillance for PED and are not linked to the current investigation.

The appearance of the virus has prompted producers to follow strict bio-security measures in an effort to limit the spread of the disease, which is fatal to baby pigs. 

Officials said the investigation into how the virus arrived on the single infected farm in Manitoba continues, but feed and the movement of an infected pig onto the farm have been ruled out as possible sources.

The province said there are now 32 farm premises that have tested positive for PED across Canada, including one in Manitoba, one in Prince Edward Island, one in Quebec and 29 in Ontario.