Washington health officials assisting with 2 hantavirus investigations

OLYMPIA – The Washington State Department of Health (DOH) is working with local and federal partners on two separate hantavirus-related investigations. One investigation involves individuals potentially exposed to cases linked to the MV Hondius cruise ship outbreak, while the other involves a hantavirus infection unrelated to the cruise ship. The cases involve different virus strains and exposure circumstances and are not connected.

Hantaviruses are a group of viruses carried by different rodent species. Hantavirus pulmonary syndrome (HPS) is a rare but serious disease caused by exposure to infected rodents or their droppings, urine, or saliva. About one out of three people diagnosed with HPS have died. The risk of contracting any strain of hantavirus remains very low.

Investigation 1: Andes virus exposure monitoring in Washington

Earlier this week, Public Health – Seattle & King County announced monitoring of three King County residents who were potentially exposed to the Andes strain of hantavirus linked to the MV Hondius cruise ship. Two individuals were exposed during an international flight by a passenger who was later diagnosed with Andes virus, and one individual was exposed on the cruise ship. All three people are currently asymptomatic. Potentially exposed people are monitored for 42 days after their last exposure to a person infected with the Andes virus.

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Additionally, CDC has notified DOH of three additional Washington residents who were on the same international flight as two of the King County individuals and are considered to have low-risk exposures. One individual is a King County resident. The other two residents live in Eastern Washington. DOH is not releasing further details to protect individual privacy. Out of an abundance of caution, local health jurisdictions are reaching out to these individuals to assess exposure and monitor them for symptoms.

Andes virus is a type of hantavirus spread by rodents in South America. The rodents that carry the virus have not been found in the United States. In rare cases, Andes virus can spread from person to person, typically through prolonged, close contact with someone who is ill. No cases of Andes virus have been reported among Washington residents.

Local health jurisdictions are in regular contact with impacted residents to monitor for symptoms during the 42-day incubation period associated with Andes virus.

Investigation 2: Sin Nombre virus hantavirus pulmonary syndrome case in Chelan County

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Today Chelan-Douglas Health District reported the first case of Sin Nombre virus hantavirus in Washington state this year. This case is not connected to the MV Hondius cruise ship outbreak, which was caused by a different type of hantavirus.

Sin Nombre virus-infected deer mice are found throughout Washington. Infected deer mice can spread the virus through urine, saliva, and droppings. People can become infected by breathing contaminated dust when disturbing rodent droppings, urine, nests, or nesting materials, particularly in enclosed or rodent-infested spaces. Less commonly, people can be infected by touching contaminated objects and touching their eyes, nose, or mouth, or by being bitten or scratched by an infected rodent.

Any activity that puts you in contact with deer mouse droppings, urine, saliva, or nesting materials can place you at risk for infection. For information on how to safely clean areas where rodents may be present, DOH recommends the following guidance.

DOH has tracked hantavirus cases since 1994. The state typically reports one to five Sin Nombre hantavirus cases each year. Unlike Andes virus, Sin Nombre virus does not spread from person to person.

The risk to the public from any hantavirus is very low because:

Sin Nombre virus infections can be prevented by avoiding contact with rodents and rodent-infested areas and using wet-cleaning methods when cleaning rodent droppings, dead or trapped rodents, or nesting materials.
Andes virus person-to-person transmission can be limited through early identification of cases and monitoring of close contacts.