Indiana Board of Animal Health spokeswoman Denise Derrer would not disclose where the facility was, or how many people and pigs became ill, but said four samples came back positive for the virus.

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The USDA said in a statement the pigs, as well as caretakers have fully recovered.

Infected pigs can pass a virus onto others in the herd, but must pass inspection before slaughter to make sure the pork is disease-free.

"This particular virus, it runs its course in the pig, and once they've recovered, they're safe to consume," said state veterinarian Dr. Bret Marsh. "Animals that are presented for slaughter have inspections as a live animal, and during the slaughter process."

Agriculture experts also said that the virus does not reside in the animal's muscle tissue, so it cannot be contracted if it is consumed.

"The Indiana State Department of Agriculture would like to reiterate that people cannot get the flu from eating pork or pork products. Pork is safe to eat," said ISDA spokeswoman Jeannie Keating in a statement.

At least one pig from Minnesota tested positive for the virus last month, the first case of a pig contracting the virus in the United States, but that did not involve a commercial herd.