Minnesota has recorded its second case of a new strain of swine flu, in a man who bought a pig at a live-animal market in Dakota County.

But no cases have surfaced at the Minnesota State Fair so far, state officials said Wednesday.

Veterinarians have been on high alert at the fair because of concern about the virus, known as H3N2v, which can spread from pigs to people and has infected nearly 280 people nationwide.

As of Wednesday, three pigs with flu-like symptoms had been isolated from the Swine Barn and tested for the flu virus, said Dr. Tom Hagerty, the fair's head veterinarian.

Two turned out to have a different strain of flu, H1N2, and were being removed from the fairgrounds Wednesday evening, said Brienna Schuette, the fair's spokeswoman. Test results on the third pig are still pending.

But Hagerty said it's not unusual for a handful of animals to fall ill during the fair.

Last week, Minnesota reported its first human case of the new virus, in a preschooler who visited a live-animal market on Aug. 10. The second case, reported Wednesday, was linked to a live-animal market on Aug. 17.

The virus is said to be relatively mild and has "not become more virulent or more easily spread," the Minnesota Department of Health said.

The new swine flu has surfaced in at least 10 states this summer. So far it resembles ordinary seasonal flu, with symptoms that include fever, cough and a runny nose.

Concerns about the possible spread of the virus at the fair prompted extra precautions, including warnings that young children, pregnant women and the elderly avoid the swine exhibits.