Eleven people from eight states have been infected with the Salmonella strain, the CDC reported on Jan. 25, with one person being hospitalized. There have been no deaths.

The infections began in late October, and since then have been linked to contact with pet hedgehogs. All but one of the infected reported contact with a hedgehog prior to getting sick, and the outbreak strain was found in samples from three hedgehogs in two ill patients’ homes in Minnesota.

Thus the CDC is warning pet owners to wash their hands thoroughly after “touching, feeding, or caring for a hedgehog or cleaning its habitat.” Hedgehogs can carry Salmonella germs in their droppings—even if they appear healthy—and germs can easily spread to their bodies, toys, bedding, or habitat.

Hedgehog owners are advised to clean habitats and supplies outside the house if possible, or at least outside of areas where food is prepared or stored. Hedgehogs should also be prevented from roaming in these areas.

Salmonella usually presents as diarrhea, fever, and stomach cramps shortly after being exposed to the bacteria. The CDC reports the illness usually resolves in around four to seven days without treatment, but occasionally severe diarrhea can lead to hospitalization. The bacteria can also spread to the bloodstream, and—in very rare cases—lead to death.

The reported illnesses linked to hedgehogs have affected people ages two to 28, with a median age of 12. They’ve occurred in Colorado, Maine, Minnesota, Mississippi, Missouri, Nebraska, Texas, and Wyoming. In some places—including Georgia, California, Hawaii, Pennsylvania, Washington, D.C., and New York City—owning a hedgehog is illegal due to public health concerns.

This isn’t the first time the CDC has sent out advice for pet owners: in October, the agency told people they could dress their pet chickens in Halloween costumes after a Louisiana news station had reported otherwise. The one caveat? You have to wash your hands.