CHICAGO (CBS) — The Illinois Department of Public Health has a warning for people who own rats as pets. It said a rat-borne virus rarely seen in humans has been confirmed in six people in Illinois.

WBBM’s Steve Miller reports it’s called the Seoul virus, as in Seoul, South Korea. According to the Illinois Department of Public Health, symptoms may include fever, severe headache, back and abdominal pain, chills, blurred vision, redness of the eyes, or rash.

Department spokeswoman Melaney Arnold says the six human cases of Seoul virus are associated with rats that came from two rat-breeding farms, also known as “ratteries.” The farms are located in East Central and Northwest Illinois.

“At this time those ratteries are not selling rats. And because the virus is not transmitted from person to person, there’s very low risk to anyone,” she said.

According to Arnold, five of the six people showed no symptoms, while the sixth has recovered. She said the Seoul virus typically comes from wild rats, and it’s not clear how the virus snuck into the ratteries.