The Centers for Disease Control and Prevention said Friday that it is investigating a multistate salmonella outbreak linked to pet hedgehogs, and warned owners of the pets not to touch them.

The CDC cautioned hedgehog owners not to “kiss or snuggle hedgehogs, because this can spread Salmonella germs to your face and mouth.”

More than half of the sick people contacted by the CDC said they had touched or been around a hedgehog, and three hedgehogs responsible came from two sick people’s homes.

“The fact that hedgehogs are a risk is not new,” Jane Sykes, professor of small animal internal medicine at the University of California, Davis, said to the New York Times.“ But we don’t know how common the shedding of salmonella is among hedgehogs specifically.”

The CDC also said hedgehog owners should wash their hands after playing with hedgehogs, clean their habitats and toys, and keep them from the kitchen or wherever food is stored.

Two people have been hospitalized since the CDC issued a first warning in October 2018. Hedgehogs were responsible for a similar outbreak from 2011 to 2013, infecting 26 people and killing one.

The CDC said children under five, adults over 65, and anyone with a compromised immune system should keep their distance from hedgehogs and that families should consider choosing a different pet.