TORONTO -- A deadly pig virus that has infected at least two Ontario farms could cost the Canadian pork industry tens of millions of dollars if it spreads across provincial borders, a group representing Ontario's hog farmers warned Monday.

Officials announced a second case of porcine epidemic diarrhea was confirmed this weekend in a farm in Chatham-Kent, as well as a possible third case in the same region.

The first case, a farrow-to-finish farm in southwestern Ontario, was found last week -- a discovery that heightened concern among the country's hog producers.

"We do anticipate that this will be tough on our industry. It's all going to depend on where it goes from here," said Amy Cronin of Ontario Pork.

"We are putting into place measures to try to manage the virus as best we can and keep it off as many farms as we can given that it is very contagious," she said.

"We estimate that if it were to spread past Ontario throughout Canada, within one year, it could cost $45 million to the Canadian pork industry."

Porcine epidemic diarrhea is usually fatal in young pigs but older animals can recover. Producers have long worried that PED might make its way up from the U.S., where it has killed millions of piglets.

Ontario's chief veterinarian said hundreds of piglets -- nearly 100 per cent of those between two and five days old -- have died so far at the first farm, located near London, Ont.

The other two hold older pigs and have not seen "significant mortality," Greg Douglas said.

Officials said the virus does not affect food safety and is not a risk to human health.

It's unclear where the virus came from but Douglas said there appears to be an "indirect link" between the affected farms.

"We still are under the impression that there are strategies which we can work on to help mitigate, slow the spread of this virus in Ontario," he said in a news conference.

"However, the confirmed case, second case and the third under suspicion certainly does change the situation -- the reality -- here in Ontario."

So far, the province has stopped short of imposing a quarantine, saying farmers are co-operating and neither pigs nor animal products are leaving the infected farms.

And there is no plan to halt the transport of pork between Canada and the U.S., said Harpreet Kochhar, Canada's chief veterinary officer.

He said border officials are "very vigilant" and require certification proving the animals are healthy. Pigs not destined for slaughter or breeding must be quarantined, he said.

What's more, Canada ships more pigs south than it takes in, he said, suggesting it would not be in the country's interest to shut down pork trade.

Ontario Pork has warned PED spreads through contact with manure. It recommends strict cleaning and disinfecting protocols to prevent the pathogen from being transferred from trucks, trailers and clothing.

Producers should also contact their vets at the first signs of diarrhea or vomiting in their herds, the organization said.

PED is not a federally reportable disease in Canada, which means there is no single set of protocols to help prevent it from spreading here or to deal with an outbreak.

Instead, provinces and the industry are sharing information and developing plans to contain the disease.