90-Second Read: Three Washington residents were exposed to Hantavirus amid the cruise outbreak. Why risk of further spread is low

Spread of Hantavirus aboard the cruise ship, however, originates from the Andes strain. One of those passengers is a King County resident who is currently asymptomatic and being monitored with other Hantavirus-exposed Americans at a quarantine center in Nebraska. Two other King County residents were exposed to the virus because they sat on an airplane near an ill cruise ship passenger who was removed before takeoff and later tested positive for Hantavirus. Hantavirus is more difficult to spread than COVID-19, and human-to-human transmission does not occur in the Hantavirus strain typically found in the United States.

There have been three deaths and at least 10 cases connected to the ship. Since surveillance of the virus began in 1993, there have been 890 cases of Hantavirus reported in the United States. There have been 61 cases of Hantavirus in Washington state since 1993. History is not likely to be repeated with a recent ship overrun with Hantavirus.

Mice and other animals carrying the disease typically do not get sick, but humans are at high risk of death if they contract Hantavirus. Hantavirus infection is much rarer than coronavirus or the flu because human-to-human transmission has only been observed in one strain of the disease that is only found in South America. The Andes Hantavirus strain is spread by the long-tailed pygmy rice rat, which is only found in Chile and parts of Argentina. The dominant form of Hantavirus in North America is the Sin Nombre strain, which is spread by the deer mouse.

Twenty of those Washington residents have died from the disease after contracting the virus. An individual who contracted the disease in 2024 recovered, but a man in 2017 died from complications related to his Hantavirus infection. These early symptoms will develop into Hantavirus Pulmonary Syndrome, which causes intense coughing, difficulty breathing and low blood pressure.