Hantavirus, a respiratory virus spread by rodents, has been in the news recently

Found a Mouse in Your Home? Here's When You Actually Need to Worry About Hantavirus Experts explain what you need to know about the illness, including what to do if you find signs of rodents in your home

• Hantavirus is a rare but potentially deadly respiratory illness spread by infected deer mice.
• Humans catch the illness from exposure to rodent droppings or urine, but the risk is low, even if you’re dealing with rodents at home.
• If you find signs of mice, experts recommend sealing up your home, cleaning safely, and seeking medical care if symptoms appear.

Hantavirus, a respiratory virus spread by rodents, has been in the headlines in recent weeks; the virus was responsible for the February death of Betsy Arakawa, 65, the wife of actor Gene Hackman.

An investigation report shared that Arakawa had been searching for information online about flu-like symptoms and breathing techniques in the days before she died, according to The Associated Press.

The report also said there were rodent droppings, a nest, and traps on the couple’s Santa Fe, New Mexico, property. Though there didn’t appear to be any rodent activity in the house itself.

Arakawa's shocking death has brought newfound attention to hantavirus and the pulmonary infection it causes, which is rare but can be deadly.

But despite the fact that millions of Americans have reported seeing rodents in their home, most people don’t need to worry about contracting hantavirus if they spot a mouse in their home, experts said.

“Obviously, rodent infestations and exposure are quite common, but they rarely ever actually result in hantavirus infection,” Brian Dawes, MD, PhD, infectious disease fellow and postdoctoral researcher at Stanford Medicine, told Health.

What Is Hantavirus?

There are many different types of hantaviruses that spread around the world—all of which are transmitted from rodents to humans—but the main one found in the U.S. is called the Sin Nombre virus, said Otto Yang, MD, professor of medicine in the division of infectious diseases at the UCLA David Geffen School of Medicine.

Hantavirus is mainly carried by the deer mouse, which typically lives in rural areas west of the Mississippi River, such as Colorado, New Mexico, Arizona, and California.

These mice “tend to have it without getting sick and spread it to each other,” Yang told Health. However, sometimes deer mice can pass the virus to people.

Humans can contract hantavirus if they inhale airborne particles released from an infected rodent’s urine, saliva, or feces. In rare cases, a bite can trigger an infection, but the vast majority of cases are caused by inhalation, according to Dawes.

Once the virus is in your system, it can lead to hantavirus pulmonary syndrome (HPS).

HPS causes flu-like symptoms such as fever, fatigue, and muscle aches anywhere from one to eight weeks after a person is first exposed to the virus. Though it’s less common, some people with HPS will also experience chills, dizziness, headaches, or gastrointestinal symptoms such as nausea, vomiting, or diarrhea.

How Common—And Deadly—Is Hantavirus?

The majority of people recover from hantavirus infections, particularly if they only have more mild symptoms. However, others may get sicker and develop chest tightness, coughing, shortness of breath, and fluid in their lungs. Roughly four in 10 people who develop HPS die from it, according to the Centers for Disease Control and Prevention (CDC).

Luckily, hantavirus is quite rare. CDC data show that a total of 834 HPS cases were reported between 1993 and 2022. The bulk of these—94%—occurred west of the Mississippi River and roughly a third were fatal.

It’s not totally clear how these people became infected with hantavirus, or what transmission most commonly looks like. Experts aren’t sure exactly how long you have to be near an infected rodent—or their droppings, urine, or saliva—to get sick.

“It’s hard to know, because we obviously can’t experiment by testing exposures of people to the carrier rodents,” said Yang.

That said, there do appear to be some trends. Most cases occur after indoor exposure to rodents—think cabins in rural locations, he explained. And because the virus is primarily spread through the air, it’s less likely that people get sick after being bitten by a mouse.

How Concerned Should You Be About the Virus?

Hantavirus is rare, so your risk of getting sick is still low, even if you're dealing with rodents in your home.

Your risk really depends on where you live. Deer mice—the rodent that mainly carries hantavirus—usually stick to rural areas out west.

But “common house mice (Mus musculus), which are prevalent in urban and suburban communities, do not carry hantavirus,” said Charles Chiu, MD, PhD, professor of laboratory medicine in the division of infectious diseases at the University of California, San Francisco. That means if you live in a city or the suburbs, it’s very unlikely you would catch hantavirus.

And, even in a Western, rural area, your property would need to be infested with wild rodents carrying the virus. Plus, not all deer mice can get you sick—an older study estimated roughly 10% to 14% of deer mice carry hantavirus, while a 2024 study of rodents in New Mexico found less than 9% of deer mice had the virus.

Essentially, if you’re walking outside and see a mouse run by, “the risk is likely minimal,” said Yang. However, if you’re vacationing in a cabin in Yosemite National Park—an area with a lot of mouse activity and history of outbreaks—”you should be more concerned,” he said.

What to Do If You Have Mice in Your Home—Or If You Develop Symptoms

If you see signs of a rodent infestation in your home—in particular, mouse droppings—it’s always a good idea to proceed with caution. Since they can carry hantavirus or other infectious diseases, “always treat rodent droppings as potentially infectious,” said Dawes.

Chiu recommends sealing up your home with the help of an expert. You can also get rid of any potential nesting areas and trap any visiting rodents.

You should clean up different spaces that might have been infested with rodents, too.

Air out your home for 30 minutes before cleaning, then use gloves and wear a high-quality face mask, the CDC suggests. Instead of sweeping or vacuuming, wipe down floors and surfaces with a disinfectant or bleach. “This will help kill most of the virus and make the feces [and] urine damp so that it is harder to get into the air,” said Dawes.

Still, stay upwind while you’re cleaning to further lower your risk of accidentally inhaling potentially contaminated dirt or dust.

If you develop any flu-like symptoms after being around mice in a rural environment, you should go to an emergency room—ideally one that has an intensive care unit (ICU), advised Yang.

HPS is typically treated with supportive care. And though some evidence suggests an antiviral drug called Ribavirin may be helpful, more data is needed to better understand the drug’s effects.

But it’s important to tell your doctor if you were potentially exposed to rodents—that way, they can identify (and treat) the infection sooner. “The earlier, the better,” said Yang, “because HPS can progress very quickly.”

Edited by Health, where she edits and publishes news articles on trending health and wellness topics. Her work has been featured in The Heights, an independent student newspaper at Boston College, and Minnesota Monthly." tabindex="0" data-inline-tooltip="true"> Julia Landwehr Julia Landwehr Julia is the associate news editor for Health, where she edits and publishes news articles on trending health and wellness topics. Her work has been featured in The Heights, an independent student newspaper at Boston College, and Minnesota Monthly. learn more

This story originally appeared on: Health News - Author:Julia Ries