Possible hantavirus case reported in Illinois. What to know about risk level
The Illinois Department of Public Health reported Tuesday it is investigating a potential hantavirus case that is unrelated to the recent MV Hondius cruise ship outbreak.
The U.S. Centers for Disease Control and Prevention is conducting additional testing to confirm the case, and it could take 10 days to complete the test. The individual with the suspected hantavirus case received an antibody test, but they are not considered definitive, according to IDPH.
State health officials reported the resident with the suspected hantavirus case lives in Winnebago County and is suspected to have a North American strain of the virus, possibly acquired while cleaning a home where there were rodent droppings.
Are Illinois residents at risk of hantavirus?
“Unlike the Andes strain of Hantavirus responsible for the cruise outbreak, the North American strains are not known to spread from person-to-person. The risk of contracting Hantavirus of any kind remains very low for Illinois residents,” IDPH officials said in the May 12 press release.
The Winnebago County resident has not traveled internationally or come into contact with those associated with the cruise ship outbreak, IDPH reported. The resident is not seriously ill, officials said, and is recovering after mild symptoms that did not require hospitalization.
“The Illinois Department of Public Health (IDPH) has not been notified of any Illinois residents being passengers on the MV Hondius during the Hantavirus outbreak. IDPH will proactively update the public should there be any changes,” IDPH officials said in a May 11 statement. “While the risk to Illinois communities is currently very low, IDPH is coordinating closely with health care providers, local public health departments, and emergency management partners. IDPH will continue to monitor the situation closely and provide timely information to the public should there be any notable updates.”
Hantaviruses are a family of viruses, primarily spread by rodents, that can cause serious illness and death in people who are exposed to infected rodent urine, droppings or saliva.
Illinois has reported seven positive hantavirus cases since 1993, excluding the recent potential case. The most recently confirmed case was in March 2025.
What to know about hantavirus: Symptoms, how it’s spread
Andes virus is the only hantavirus known to spread person-to-person, according to the CDC. The rodents that carry Andes virus, primarily the long-tailed pygmy rice rat, have not been found in the U.S.
Hantaviruses found in the U.S. can cause hantavirus pulmonary syndrome, most commonly spread by the deer mouse.
Hantavirus pulmonary syndrome is severe and potentially deadly, and it affects the lungs, the CDC reports. Symptoms typically begin to present between one and eight weeks after exposure, and early symptoms can include fatigue, fever and muscle aches. Four to 10 days after disease onset, late symptoms can occur, and include coughing and shortness of breath.
The CDC reports 38% of people who develop respiratory symptoms from hantavirus pulmonary syndrome may die from the disease.
The World Health Organization reports there is no licensed specific antiviral treatment or vaccine for hantavirus infection. Supportive care may be needed, and focuses on monitoring and managing respiratory, cardiac or kidney complications.
“Early access to intensive care, when clinically indicated, improves outcomes, particularly for patients with hantavirus cardiopulmonary syndrome,” WHO reports.
How to prevent hantavirus infection
To reduce your risk of contracting a hantavirus infection, the Illinois Department of Public Health recommends trying to keep homes and other buildings rodent-free.
Here are some best practices Illinois residents can use to prevent rodent infestations, from IDPH:
- Reduce the availability of food and water by storing food in tightly closed containers, keeping your kitchen clean and repairing leaky faucets.
- Eliminate nesting sites near the building by keeping grass mowed and keeping gardens, wood piles, compost heaps and trash cans at least 100 feet from your home.
- Identify possible rodent entry sites and seal them. A mouse can fit through a hole just slightly larger than a quarter of an inch.
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