Hantavirus in the U.S.: Where Cases Occur Most and What You Need to Know

For three decades, the U.S. Centers for Disease Control and Prevention has tracked a rare but often deadly virus known as hantavirus. While the disease remains uncommon, understanding where it has historically appeared can help people take simple steps to protect themselves and their families.

Hantavirus first gained national attention in 1993, when an outbreak of severe respiratory illness struck the Four Corners region — the area where Arizona, Colorado, Utah, and New Mexico meet. Since then, the CDC has recorded 890 laboratory-confirmed cases of hantavirus in the United States through 2023. Of those, 859 cases involved hantavirus pulmonary syndrome, a serious lung infection, while the remaining cases were non-pulmonary infections.

The disease carries a sobering statistic: about 35% of people who contract hantavirus die from it. That is roughly one out of every three people infected.

How Hantavirus Spreads

Hantavirus is not spread from person to person in the United States. Instead, people catch it through contact with rodents — specifically their urine, saliva, or droppings. The virus can become airborne when these materials are stirred up, for example when someone sweeps a shed or cabin where mice have been active.

A study published in the journal PLOS Pathogens found that more than 30 species of rodents and small mammals in the Southwest carry hantavirus. This helps explain why certain parts of the country see more cases than others.

According to infectious disease experts, the most common type of hantavirus found in the U.S. is called Sin Nombre virus. This is different from the Andes virus, which was linked to a recent cruise ship outbreak that made headlines. Sin Nombre virus is the strain responsible for the vast majority of U.S. cases.

Where Hantavirus Cases Have Occurred

The geographic pattern of hantavirus in the U.S. is striking. A full 94% of all confirmed cases have occurred west of the Mississippi River. The Four Corners region and California account for the largest share.

Here is a breakdown of the states with the highest number of cases since 1993:

• New Mexico: 129 cases
• Colorado: 121 cases
• Arizona: 92 cases
• California: 79 cases
• Washington: 61 cases

Other western states also report cases, though in smaller numbers. On the other side of the country, cases are far less common. In fact, 10 states have never reported a single case of hantavirus. These are mostly in the Northeast and Midwest, though experts caution that the virus could appear anywhere rodents are present.

Who Gets Hantavirus?

CDC data shows that nearly two-thirds of confirmed cases — 62% — were in men. The median age of patients was 38 years old, though cases ranged from children as young as 5 to adults as old as 88. Most patients were white, accounting for 75% of cases, and 66% were non-Hispanic or Latino.

These numbers likely reflect who is most exposed to rodents. People who work in agriculture, construction, or outdoor occupations may have higher contact with rodent habitats. Similarly, people who clean out cabins, barns, or sheds in rural areas face greater risk.

Why This Matters for Readers

Hantavirus is rare, but it can be severe. For anyone living in or traveling to the western United States — especially the Four Corners region — awareness is key. The disease can start with fever, muscle aches, and fatigue, then rapidly progress to difficulty breathing. Because symptoms can resemble the flu, it is easy to overlook early signs.

If you live in a rural area, own a vacation cabin, or spend time outdoors, you may be at higher risk without knowing it. Rodents often seek shelter in homes, garages, and outbuildings, especially during colder months. Even a small mouse infestation can create conditions where the virus could spread.

Health experts stress that hantavirus is preventable with simple precautions. The disease does not require special equipment or medical training to avoid — just careful habits.

What Experts Say About Prevention

Infectious disease specialists recommend a few straightforward steps to reduce your risk:

• Seal up holes and gaps in your home, garage, and shed where mice can enter. Use steel wool, caulk, or metal flashing.
• Store food in rodent-proof containers and keep pet food sealed.
• Clean up rodent droppings carefully. Never sweep or vacuum them dry. Instead, spray them with a bleach solution (1 part bleach to 9 parts water), let sit for 5 minutes, then wipe up with a paper towel.
• Wear gloves and a mask when cleaning areas that may have rodent activity, such as attics, basements, or cabins that have been closed up.
• Avoid disturbing rodent nests or dead rodents directly.

These precautions are especially important in the spring and fall, when rodents often move indoors seeking food or shelter.

Hantavirus in the News

Hantavirus made headlines recently when it was reported that the wife of late actor Gene Hackman died from a hantavirus infection in New Mexico. This tragic case renewed public interest in the disease and reminded many people that even in modern homes, rodent-borne illnesses remain a real threat.

The case also highlighted that hantavirus can strike anywhere in the region where the deer mouse — the primary carrier of Sin Nombre virus — is common. Deer mice are found throughout most of the western and central United States.

Practical Takeaways

While hantavirus is serious, the risk to the average person remains low. The CDC has tracked only 890 cases over 30 years across the entire country. For context, that is fewer than 30 cases per year on average.

However, because the death rate is high, it pays to be cautious. Here are the key points to remember:

• Know your region. If you live in or visit the western U.S., especially the Four Corners area or California, take rodent prevention seriously.
• Recognize symptoms. Early signs include fever, fatigue, muscle aches, and dizziness. If you develop shortness of breath after possible rodent exposure, seek medical help immediately.
• Act quickly. There is no specific cure for hantavirus, but early supportive care in a hospital can improve outcomes.
• Prevent exposure. Simple home maintenance — sealing entry points, cleaning up food, and using proper cleaning methods — can virtually eliminate your risk.

Hantavirus is a reminder that even in the 21st century, nature still presents health challenges. But with knowledge and a few practical steps, you can protect yourself and your loved ones from this rare but dangerous disease.

Source: MedPage Today