Hantavirus in Colorado since 1993

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Hantaviruses are a family of viruses spread by rodents that cause varied disease syndromes in people worldwide. The most important hantavirus in Colorado is the Sin Nombre virus, which can cause Hantavirus Pulmonary Syndrome (HPS), a severe and potentially deadly respiratory virus. People most frequently become infected with Sin Nombre virus when they inhale aerosolized virus that infected deer mice shed in their urine, feces, and saliva.

Deer mice can live in a wide variety of habitats and are found throughout Colorado although they tend to be most abundant in rural areas. Early spring and summer are when most human cases of hantavirus infection occur, but cases have been detected in almost every month. Exposures can occur in any area where mice are present, including rural and urban areas. Risks include exposures to rodents through outdoor work, rodent presence in the household, and cleaning previously unoccupied buildings.

Although not all people who get sick say they touched rodents, people commonly say they noticed more mice or were in buildings that had mice. Hantavirus symptoms begin one to eight weeks (average two weeks) after exposure. Symptoms include fever, chills and severe pain in the legs and back. About half of people with hantavirus also experience nausea, vomiting and diarrhea. After one to seven days of illness, the disease may begin to affect the heart and lungs.

Rodent control in and around homes and outbuildings is the best way to prevent hantavirus infection.

Early recognition of Hantavirus Pulmonary Syndrome is critical in reducing deaths. All cases of hantavirus must be reported to the Colorado Department of Public Health and Environment. For consultation on suspected cases, contact us at 303-692-2700 (regular business hours) or 303-370-9395 (after hours, weekends and holidays). The State Public Health Virology Laboratory can be reached at 303-692-3485.

Colorado residents affected by hantavirus by county of residence, 1993-2023