Three pigs may be the first in the US with Swine Flu

Three pigs at the Minnesota State Fair tested positive in late August for H1N1, the flu virus that is causing the current pandemic, the Agriculture Department reported Friday.

The department said the test results were preliminary and would not be confirmed for a few days. But if the results are confirmed, the pigs will be the first in this country found to harbor the virus. Infected pigs have been found in eight other countries.

The virus does not seem to make pigs very sick. Of 103 pigs tested at the Minnesota fair, in St Paul, only three were found to be carrying the virus, and all appeared healthy. They probably caught the virus from infected people, researchers said.

Officials at many state fairs this year worried that people would infect pigs and that reports of infected pigs would create a scare that would harm the pork industry, even though there is no risk of infection from eating cooked meat.

It is not clear what the findings mean for public health, scientists said. The virus is already spreading widely among people, and in fact is far more common in humans than in pigs, so people seem far less likely to catch it from pigs than from one another.

“It’s not surprising to find it in pigs,” said Dr. Jeff Bender, director of animal health and food safety at the University of Minnesota, who conducted the testing along with researchers from the University of Iowa. “We do know that viruses move between species.”

One concern about animals’ harboring the virus is the possibility that viruses will change as they move back and forth between species, perhaps by mixing with other viruses.

A veterinarian for the Minnesota State Fair, Dr. Tom Hagerty, was traveling on the East Coast late Friday and said he had not heard of the test findings. Dr. Hagerty sounded surprised at the news but not alarmed, because most of the pigs, or perhaps all, that were at the state fair at the same time as a group of 4-H children who became ill were to be sent to the slaughterhouse shortly afterward.

“I would be much more bothered if I heard that these had been breeding pigs,” he said.