(Reuters Health) - - People with pet rats should practice safe rodent handling and good hand hygiene to avoid catching a virus that can jump from rats to humans, infectious disease experts warn.

Doctors in the U.S. and Canada have seen cases of Seoul virus infection in humans who contracted the virus from their pet rats, according to a report in Morbidity and Mortality Weekly Report.

“In December 2016, a patient in Wisconsin was hospitalized for fever and a low white blood cell count and ultimately tested positive for Seoul virus. Soon after, a family member developed similar symptoms and also tested positive,” Dr. Janna Kerins of the U.S. Centers for Disease Control and Prevention (CDC) told Reuters Health in an email.

After confirming Seoul virus infection in the Wisconsin patients, the CDC and the Wisconsin Department of Health Services investigated the source of the disease.

“The outbreak spread from sales or trade of infected pet rats between people’s homes or between ratteries” - places where rats are bred – “in 11 states,” said Kerins, who coauthored the report.

Overall, researchers identified 24 people in the U.S. and Canada who developed acute Seoul virus infections after contact with pet rats. Eight became ill, and three were hospitalized but recovered, said Kerins.

Seoul virus is a type of hantavirus found in Norway rats, one of the most common varieties of rats in the United States. The virus does not cause symptoms in the rats, though. And people with Seoul virus infections often have no or mild symptoms, but “kidney failure or death can occur in rare cases,” said Kerins.

“This is a good reminder that rats and other rodents can carry hantavirus without looking sick, so it is important for owners of pet rats to be aware of the risk for Seoul virus infection, and to practice good hand hygiene . . . such as washing hands after handling rodents and before preparing food, and by avoiding rat bites and scratches,” Kerins said.

Healthcare providers should consider Seoul virus infection in patients with compatible symptoms and rat contact, wrote the authors.

In addition, physicians and other medical providers should contact their state or local health department when they suspect a patient has a Seoul virus infection.

SOURCE: bit.ly/2nPjV7s Morbidity and Mortality Weekly Report, online February 2, 2018.