Environmental Health Advisories

Health Advisories

Take Precautions to Avoid Hantavirus

State health officials warn Coloradans to avoid hantavirus exposure while cleaning cabins or other buildings that were closed up for winter. Hantavirus is a serious and potentially fatal respiratory disease carried by deer mice. When cleaning out rodent-infested structures, people can breathe in dirt and dust contaminated with deer mouse urine and feces and become infected. There have been three confirmed cases of hantavirus in the state this year, including one death.

The Colorado Department of Public Health and Environment has documented more than 80 cases of hantavirus since it began tracking the disease in 1993. More than one-third of these individuals died from the infection. Most Colorado hantavirus cases happen when people are exposed to deer mouse urine and feces in and around their residences.

People are urged to be particularly careful where there is evidence that mice have been in and around buildings or wood or junk piles. An increase in the number of mice around a home often precedes a person getting the disease.

"Last year's abundant rainfall and the present heavy snowpack have provided moisture for ample vegetation for rodents to eat. As a result we see an increase in deer mouse populations," said Dr. Jennifer House, state public health veterinarian at the department. "May, June and July are the months when most human cases occur. People need to take precautions to prevent exposure to hantavirus before they begin cleaning structures that have evidence of rodent activity."

Dr. House said to ventilate structures before cleaning and spray any accumulation of dust, dirt and mouse droppings with a mixture of bleach and water. "Never vacuum or sweep an area without first spraying it down," she emphasized. "If you have deer mice around your home, assume there is some risk of exposure to this virus. The more mice, the greater the risk, but some people have been infected by handling a single mouse."


  • Rodent-proof buildings by plugging holes or other mouse entryways. Conduct year-round rodent control or hire a professional exterminator.
  • Keep indoor areas clean, especially kitchens. Dispose of garbage in sealed containers.
  • Store food in rodent-proof containers, including food for pets, livestock and birds.
  • Remove rodent hiding places near the home such as wood, junk and brush piles. Store firewood at least 100 feet from your house. Keep vegetation around the house well-trimmed.

Hantavirus Symptoms

Hantavirus normally begins with fever, body aches, headache and vomiting. The symptoms begin from one to six weeks after exposure.

At first there are no respiratory symptoms. However, the illness can quickly progress to respiratory distress within one to five days. People may have a dry cough and difficulty breathing caused by the lungs filling with fluid.

Because no effective treatment exists for the disease, Dr. House emphasized prevention as the key.

"When hantavirus infection is suspected, early admission to a hospital for careful monitoring is critical. Treatment of symptoms and supportive therapy can be provided in the hospital," Dr. House said. "If you become ill with these symptoms, it is important to tell your physician about possible exposures to deer mice or rodent-infested environments."

Centers for Disease Control & Prevention (CDC) Health Advisory

The Agency for Toxic Substances and Disease Registry (ATSDR) and the Centers for Disease Control and Prevention (CDC) are alerting the public to an emerging national concern regarding misuse of pesticides. Consumers should also be aware of recent cases where licensed and unlicensed pest control applicators illegally sprayed outdoor pesticides indoors. When you hire someone to control bed bugs or any other pest, make sure they are currently licensed and certified to apply pesticides. Ask to see the certification.

Ask for the brand name of the pesticide and the name of the product's active ingredient in case you or a member of your family gets sick from exposure to the product. Read the label of the product the pest control applicator is planning to use to make sure it is for indoor use. Do not use bleach in areas where you have treated your home with a pesticide. Bleach can convert some pesticides to more toxic forms that could result in harmful exposures to your family.

To learn more about pesticides: