By Brenda Goodman, CNN

The CDC reported that two people in Michigan caught flu strains, such as the virus particles shown in green, that typically circulate in pigs.
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CNN —
Two people have caught flu strains that normally circulate in pigs, the US Centers for Disease Control and Prevention said on Friday, and pig exhibits at agricultural fairs appear to be to blame.
Each patient became ill with flu-like symptoms about 10 days after visiting pig exhibits at two different agricultural fairs in early and late July. Neither was hospitalized, and their infections do not appear to have spread to other people, the CDC said.
Both cases were identified by the Michigan Department of Health. There are a few such cases in the U.S. each year, usually linked to swine exhibits at fairs.
Still, the illnesses highlight the possibility that flu viruses have the ability jump from animals such as birds and pigs to humans. Usually, cases like these don’t cause further problems because the viruses are adapted to infecting other species, but because there’s always the possibility that such a spillover could cause widespread disease, the CDC says it always fully traces and investigates these cases.
The CDC reminds people who are planning a trip to a state or agricultural fair that it’s best to avoid eating or drinking around pig exhibits at the fair, to avoid contact with animals that appear to be ill, and to wash and sanitize hands after visiting swine exhibits.
People who are immunocompromised are at higher risk from spillover infections. The CDC says they should avoid pig exhibits or wear a mask when around the animals.