The recent cases are „the first human cases we’ve seen in the United States associated with pet rats,“ said Dr. Jennifer McQuiston, a veterinarian and deputy division director for CDC’s division of high consequent pathogens and pathology. Several previous outbreaks reported in the US occurred in wild rats.
„There was an outbreak reported in Europe previously associated with pet rats, so it’s not the first time this has been associated with pets worldwide,“ McQuiston said.
Investigation in Wisconsin leads to Illinois
The initial patient in the current outbreak, a resident of Wisconsin, visited a hospital with flu-like symptoms, according to Stephanie Smiley, director of the bureau of communicable disease with Wisconsin Department of Health Services. The patient was a home-based rodent breeder.
Because of the patient’s exposure to rodents, the doctor had a „hunch“ to test for hantavirus , explained Smiley.
Following a positive test result for hantavirus in late December, Wisconsin health officials sent a sample from the patient to the CDC along with a separate sample from a second patient — a family member who also worked with rodents.
On January 11, the CDC confirmed infections with Seoul virus, a rodent-borne hantavirus, in both patients.
Though related, Seoul virus is considered different from hantavirus and it is not typically seen in the US, said McQuiston.
„This is typically associated with a milder illness than we think about with the classic hantavirus we talk about in the US, but it can be, in rare cases, associated with some more severe symptoms, such as renal disease,“ said McQuiston.
According to Smiley, symptoms of Seoul virus can include fever, chills, nausea, pink eye-type eye infection and abdominal pain. Though it rarely happens, a simple infection can progress to hantavirus pulmonary syndrome, which begins with fever, severe aches and fatigue, and may turn fatal.
Seoul virus symptoms often develop within one to two weeks after contact, but can take as long as eight weeks to appear, said Smiley.
Both of the Wisconsin patients have since recovered, but the discovery of infection led to a follow-up investigation at several rat suppliers, which revealed an additional six cases of Seoul virus among workers at two Illinois breeding facilities, according to Melaney Arnold, a spokeswoman for the Illinois Department of Public Health.
