Hantavirus kills 38% of patients with respiratory symptoms, CDC says

What the real risk looks like

Hantavirus is not a routine public threat, but it is a serious one when people are exposed to rodents. The virus family can cause hantavirus pulmonary syndrome in the Americas and hemorrhagic fever with renal syndrome in Europe and Asia, and in the United States the most common HPS virus is spread by the deer mouse. CDC says 38% of people who develop respiratory symptoms from HPS may die, which is why the disease deserves attention without panic.

The key to risk calibration is simple: most people are not exposed often, and most exposure happens in very specific settings, especially where rodents live or have left waste behind. That means the average person is not facing a general airborne threat in daily life. The danger rises when rodent urine, droppings, saliva, nests, or carcasses are disturbed in enclosed spaces.

How hantavirus spreads

People usually become infected by inhaling virus particles that have become airborne from rodent urine, droppings, or saliva. Less commonly, infection can happen through rodent bites or scratches. That transmission pattern matters because it means the problem is not casual contact with the outdoors, but close contact with rodent activity, especially during cleanup or in poorly ventilated areas.

The main U.S. carrier is the deer mouse, but it is not the only rodent linked to disease. Other carriers include rice rats and cotton rats in the Southeastern United States, and white-footed mice in the Northeastern United States. The geography helps explain why public health officials watch rodent exposures closely even though the disease remains rare overall.

What symptoms look like, and why timing matters

Symptoms of HPS usually begin 1 to 8 weeks after contact with an infected rodent. The early phase can look like many other viral illnesses: fatigue, fever, and muscle aches. Within days, the illness can worsen into coughing, shortness of breath, and fluid in the lungs, which is the stage that makes the disease so dangerous.

That rapid progression is one reason hantavirus can be missed at first. Mayo Clinic notes that the infection often starts with flu-like symptoms and may worsen quickly, while treatment options are limited. In practical terms, that means recent rodent exposure should be treated as a meaningful clue if fever and body aches are followed by breathing problems.

Children can deteriorate especially fast. A 2023 Pediatrics study of U.S. cases from 1993 to 2018 found that among 719 HPS patients, overall mortality was 35.4%, and children with HPS died more quickly than adults, with a median of 2 days from symptom onset to death among children versus 5 days in adults. That finding underscores why early recognition matters.

How rare the disease is, and where it has been seen

Hantavirus remains uncommon in the United States, but it has a long and well-documented public-health history. CDC says U.S. surveillance began in 1993 after a severe respiratory illness outbreak in the Four Corners region, where Arizona, Colorado, New Mexico, and Utah meet. HPS became nationally notifiable in 1995, and in 2014 national reporting expanded to include non-pulmonary hantavirus infections, with reporting of those cases beginning in 2015.

By the end of 2023, CDC had reported 890 laboratory-confirmed hantavirus disease cases in the United States since surveillance began in 1993. Of those, 859 were HPS cases and 31 were non-pulmonary infections. CDC also says 94% of reported U.S. cases through 2022 occurred west of the Mississippi River, which shows a strong regional pattern even though cases can appear elsewhere.

A CDC summary of surveillance data found a median patient age of 38 years and a 35% overall case-fatality rate in U.S. cases. Those numbers do not suggest a common illness, but they do show that when hantavirus does strike, it can be severe enough to overwhelm the body quickly.

What the average person should do differently

For most people, the correct response is not broad fear. It is targeted caution around rodents and the places they contaminate. If you are not handling rodent-infested areas, your everyday risk is low. If you are dealing with a garage, shed, cabin, basement, storage room, or other enclosed space with droppings or nesting material, that is where behavior should change.

The most important habits are straightforward:

• Avoid disturbing rodent droppings, nests, urine, or saliva.
• Treat signs of rodent activity as a cleanup and control problem, not a minor nuisance.
• Be especially careful in enclosed spaces where particles can become airborne when debris is moved.
• Seek medical attention quickly if flu-like symptoms follow a rodent exposure and breathing symptoms begin.

CDC notes that county-level case data are not published to protect patient identities, but local health departments can provide area-specific information. That makes local public-health guidance more useful than rumor or panic.

The bottom line

Hantavirus is rare, but its seriousness is not in question. The people most at risk are those who are exposed to rodents, their nests, or their waste, especially in enclosed spaces where contamination can be stirred into the air. For the average person, the practical lesson is narrow and clear: take rodent signs seriously, clean up cautiously, and do not ignore symptoms that follow a known exposure.