What’s the risk of hantavirus in King County?

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Hantavirus information in additional languages: Spanish | Chinese, Simplified | Chinese, Traditional

The outbreak of hantavirus on an international cruise ship has put this rare disease in the headlines. WHO is leading the investigation of that situation involving a specific type of hantavirus that has not been found in the United States. We wanted to learn more about whether hantavirus poses a risk to people in King County, so we checked in with Dr. Jocelyn Mullins, a public health veterinarian and resident expert at Public Health – Seattle & King County on diseases coming from animals. 

Dr. Mullins, what is hantavirus and how people can get it? 

Hantavirus is a rare but potentially deadly disease that affects the lungs. It primarily spreads from contact with wild rodents, especially when people are exposed to their urine, droppings, and saliva. It can also spread through a scratch or a bite by a wild rodent, but that’s even more rare. 

There are many types of hantavirus around the world, but the Andes hantavirus is the only one known to spread person-to-person, and only if there is prolonged close contact with someone who is ill. It’s found in long-tailed rice rats that live in Argentina and Chile. Andes hantavirus is the type that was found in the cruise ship outbreak. 

When people hear about a deadly virus on a cruise ship, it can give flashbacks to the early days of the COVID emergency. Do you think the hantavirus situation on the cruise ship presents a threat to people here? 

This is a deadly virus, so I can certainly understand why it’s a fear-inducing situation. But it’s also quite different than what happened with COVID-19. When COVID-19 emerged, it was a novel virus, one that hadn’t been seen before, so there was so much unknown about it. In contrast, we have more information about hantavirus from studies done since the 1990s.

COVID-19 also spreads easily between people. Even though the hantavirus found on the cruise ship was identified as Andes hantavirus, the only type with the potential for person-to-person spread, it is not easily transmitted between people. People generally would require prolonged close contact with the ill person for the infection to be transmitted.   

WHO is leading a massive contact tracing effort, which has been a key intervention in containing spread in previous outbreaks of this hantavirus. This gives me confidence. I find this graphic created by epidemiologist Dr. Caitlin Rivers helpful in explaining the risk posed by the cruise ship outbreak. 

In my reading of the situation, Andes hantavirus is a very low risk for people in King County or for people who have travel planned. 

Do we have hantavirus in King County? 

A deer mouse with a brown body and white belly on a woodpile
Deer mice have a white underbelly and a tail that’s two colors – half brown and half white. They are typically small and round, with gray to brown fur on their backs.

It’s rare, but we do have deer mice that can carry a different type of hantavirus (Sin Nombre) that does not spread person-to-person. There have been six cases in King County since 1997. In Washington state, hantavirus is carried only by deer mice. They can nest in homes, garages, outbuildings, sheds, cabins, barns, other structures, and cars, and have been reported most typically in wooded rural and suburban settings. A home or building does not need to be old or dilapidated to have nesting rodents. 

How could someone here be exposed to hantavirus? 

It’s possible to get infected with hantavirus by breathing in dust containing the virus from rodent droppings, urine, saliva, or nesting materials.  Hantavirus spreads when dust that contains the virus is stirred up into the air, such as when people sweep or vacuum in rodent-infested areas. 

It is also possible – but less likely – to get infected by touching your eyes, nose, or mouth after handling any contaminated rodent materials, or by being bitten by an infected rodent.  

What would put someone at higher risk of exposure to hantavirus? 

The chance of being exposed to hantavirus is greatest when people are in closed spaces where rodents are actively living. Activities that may place a person at higher risk include: 

  • Using or cleaning previously unused buildings, cabins, sheds, barns, garages, and storage areas, particularly when they have been closed during the winter or undisturbed for weeks or months. 
  • Housecleaning activities in and around homes with rodent infestations.  
  • Construction workers, utility workers, campground/park service staff, pest control workers, and others can be exposed when they work in crawl spaces, under houses, in and around cabins, or in vacant buildings that have a rodent population. 
  • Campers and hikers can be exposed when they use infested trail shelters such as cabins, yurts, or other shelters, or camp in rodent habitats. 
  • Exposure to cars, trailers, or mobile homes where rodents are living  

How to clean areas where rodents have been 

To manage any type of mouse infestation, make sure to properly protect yourself before removing the nest and droppings and disinfecting the area. 

  • Wear gloves and long sleeves, and have a trash bag near you. 
  • Prepare a disinfectant solution that can kill hantavirus: commercial disinfectant containing phenol such as Lysol® or a mixture that is 1 part bleach and 9 parts water. 
  • Wet down the rodent materials, place the materials in the trash bag, and wipe the area with paper towels and more disinfectant. 
  • Do not sweep or vacuum, because this will put the droppings in the air and increase chances of breathing in any hantavirus. 

Managing multiple nests and dead mice is best left to a pest control professional. 

More information on hantavirus and dealing with rodents

Get more information about safe cleaning in rodent infested areas, how to clean and disinfect vehicles with rodent infestations, and flyers in English, Spanish and Chinese: Hantavirus – King County, Washington 

Take steps to prevent rodent infestations even if you do not see evidence of rodents. For tips in many languages about preventing rodents from entering your home: Preventing rodents and keeping them away – King County, Washington 

More information from the Washington State Department of Health: Hantavirus | Washington State Department of Health

More on our blog about hantavirus:

Backyard Critter Guide: How to avoid diseases from animals – PUBLIC HEALTH INSIDER

5 important tips for staying safe when cleaning areas with rodents – PUBLIC HEALTH INSIDER

Originally published on May 8, 2026.

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