Here’s Where Hantavirus Has Historically Occurred in the U.S.

There have been hundreds of hantavirus cases in the U.S. over the 30 years that the CDC has been tracking it — and most of those cases have been in one region.

CDC began tracking laboratory-confirmed hantavirus cases in the U.S. in 1993 when there was an outbreak of severe respiratory illnesses in the Four Corners region where Arizona, Colorado, Utah, and New Mexico meet. Two years later, hantavirus became a nationally notifiable disease, meaning it is now reported through the Nationally Notifiable Disease Surveillance System when a patient has a fever and diagnosis is laboratory confirmed. The most recent CDC hantavirus data are from 2023.

In that 30-year time period, there have been 890 laboratory-confirmed hantavirus cases; 859 involved hantavirus pulmonary syndrome cases while the remainder were non-pulmonary infections. About a third (35%) of people who had hantavirus died.

According to infectious disease experts, Sin Nombre is the most common hantavirus variant in the U.S., not Andes virus, which is the variant connected to the cruise ship outbreak.

The vast majority of cases have been west of the Mississippi River (94%), with most in the Four Corners region and California. New Mexico has had the most cases since 1993, at 129, followed by Colorado at 121, Arizona at 92, California at 79, and Washington at 61. The east has had far fewer cases, and there are 10 states that have never had a case.

Hantavirus appeared in the news last year when late actor Gene Hackman’s wife died of a hantavirus infection in New Mexico.

Hantavirus is primarily spread by rodents, often by contact with the animals’ urine, saliva, or droppings. A study in PLOS Pathogens found that hantavirus is carried by more than 30 species of rodents and small mammals common in the Southwest, which contributes to the distribution of disease.

Nearly two-thirds of confirmed cases were among men (62%), and the median age was 38 (range 5-88). Most patients were white (75%) and non-Hispanic or Latino (66%).