Updated

U.S. Agriculture Secretary Tom Vilsack said on Wednesday he was confident a vaccine approved this week by the U.S. administration would help fight a deadly virus which has killed millions of pigs in the United States.

The U.S. Department of Agriculture said on Wednesday preliminary studies of a vaccine developed by Harrisvaccines "have been promising" in controlling Porcine Epidemic Diarrhea virus (PEDv). The virus has killed up to 8 million pigs and pushed pork prices to record highs since it was first identified in the United States last year.

"I don't want to say the virus will be eradicated but I think you will see we're on the other side of this," Vilsack said after a speech to representatives of the French farm sector at the U.S. embassy in Paris.

He added that warmer temperatures over the summer would weaken the virus, while systematic notification by farmers of new PEDv cases and higher biosecurity measures at farms will help in the fight against PEDv.

Vilsack ordered farmers earlier this month to start reporting cases of the deadly pig virus and pledged over $26 million in funding to combat the virus, pushing back against criticism of his handling of the outbreak.

Harrisvaccines' product is the first to win U.S. Department of Agriculture conditional approval, which means it can be sold over the counter but the company must continue to test its effectiveness.

"Hopefully by the end of the year we will be in a situation where we can say 'yes folks (the vaccine) works', start producing mass quantities of it so that farm producers around the world will not have to worry about this," Vilsack said.

He stressed the virus, which causes diarrhoea and vomiting and is nearly always lethal to baby piglets, was a global issue and not just a U.S. problem. PEDv has been found in other countries including Japan, Canada and Mexico.

The crisis and the severity of the virus has disrupted international pig trading, with 11 countries or regions, including Russia, the European Union, China and Japan limiting imports of live hogs.