Suspected Illinois hantavirus case renews concern as cruise outbreak grows

A suspected hantavirus case in Winnebago County has pushed the virus back into the national spotlight at the same moment a cruise-ship outbreak continues to grow. Illinois public health officials said the resident under investigation had not traveled internationally and had not come in contact with people tied to the M/V Hondius cluster, underscoring that this danger is not confined to one ship or one region.

The Illinois Department of Public Health said on May 12 it was investigating the potential case, and the Winnebago County Health Department said it was working with state officials. The Centers for Disease Control and Prevention said the risk to the American public remains extremely low, but the agency also said on May 15 that there were no hantavirus cases in the United States currently and no U.S. cases of the strain behind the cruise outbreak.

That outbreak has been linked to Andes virus, which the World Health Organization confirmed on May 6. By May 8, WHO had reported eight cases, six confirmed and two suspected, including three deaths. CDC says Andes virus is normally found in South America, can cause severe respiratory disease, and can spread from person to person, though that is not common.

The Illinois case fits into a longer U.S. pattern that began in 1993, when hantavirus disease surveillance started after the Four Corners outbreak in Arizona, Colorado, New Mexico and Utah. CDC says the virus was later isolated from a deer mouse trapped near the New Mexico home of a patient, a finding that helped cement rodents as the source. By the end of 2023, 890 laboratory-confirmed hantavirus disease cases had been reported in the United States since surveillance began.

New research has also complicated the old map of risk. Virginia Tech researchers identified hantavirus activity in wildlife hotspots in Virginia, Colorado and Texas, and found 15 rodent species carrying the virus, including six not previously recognized as hosts. That finding matters because it suggests the virus can surface far beyond the Southwestern story many Americans still associate with hantavirus.

Symptoms usually begin one to eight weeks after contact with an infected rodent, often with fatigue, fever and muscle aches, and can progress to coughing and shortness of breath. The practical lesson is blunt: keep rodents out of homes, workplaces, sheds and cabins, and treat rodent activity as a serious health warning in rural housing and recreation sites.