Animal-Borne Diseases

Hantavirus pulmonary syndrome (HPS) has been recognized in the United States since 1993. The CDC has issued guidelines for preventing hantavirus disease titled Hantavirus Pulmonary Syndrome — United States: Updated Recommendations for Risk Reduction.

This guideline and other information is available from the CDC hantavirus website (

For information about HPS in Washington State see the Department of Health communicable disease website (

If you have specific questions about hantavirus disease in the workplace, contact the safety and health consultant in your nearest L&I service center.†Locations and telephone number are listed in the government pages of the telephone book under "Washington, state of."

Some general precautions:

  • Don't dry sweep suspected contaminated areas without using a respirator.
  • Don't shake out contaminated clothing.
  • Soak contaminated materials in disinfectant before handling.
  • Take steps to prevent rodents from entering buildings.
  • Use gloves when handling all rodent carcasses and contaminated materials.
  • Refer to CDC guidelines for a comprehensive list.
  • Notify employer if rodent nests or droppings are spotted in the workplace.

Occupational Exposure to hantavirus pulmonary syndrome — what it means to you

Hantavirus pulmonary syndrome (HPS) is a serious, often deadly, respiratory disease passed to humans by exposure to infected rodents. Twenty-two Washington residents are known to have been stricken by the disease since it was first identified in 1994. It proved fatal for 8 of them. Although most of the cases weren't clearly related to workplace activities, one 1996 case — a fatality — was linked to workplace exposure.

More About Hantavirus

The virus is carried primarily by deer mice, although other rodents may be carriers as well. Deer mice are found in rural and semi-rural settings, but not generally in urban areas. Infected deer mice have been found throughout eastern and western Washington, with an estimated 5 to 10% of the deer mouse population infected by the virus.

How is it passed?

The virus is passed to humans through exposure to the rodent's urine, droppings or saliva. Airborne transmission may occur when dust or objects contaminated with rodent urine or droppings are disturbed. Rodent bites and ingesting contaminated food may possibly transmit the virus. There is no evidence of person-to-person transmission.

What are the symptoms?

Symptoms of hantavirus disease usually appear within 2 weeks of infection by can appear as early as 3 days or as late as 6 weeks after infection. Early symptoms are general and flu-like (fever, body aches, headache, and so forth). As the infection progresses, the individual may experience difficulty in breathing, a distinguishing symptom that can quickly progress to severe lung disease that requires intensive care intervention. No cure or vaccine is available against hantavirus disease, although the earlier that medical treatment is sought, the better the chance of recovery.

Reducing the risk for occupational exposure

Employers need to evaluate their workplaces and work activities to determine if their workers are at risk for exposure to hantavirus. If exposures are identified steps must be taken to minimize worker risk for hantavirus exposure. (The following information has been extracted from the Centers for Disease Control guidelines.)

Step 1: Determine if workers can be exposed

Consider the types of activities your workers engage in. Next, determine if these activities bring them into contact with rodents, nests, droppings or urine or if they enter rodent-inhabited areas such as abandoned buildings or crawl spaces:

  • Pest control workers and mammalogists are generally considered to have higher risk for exposure than others since they often handle rodents, traps, and other contaminated items on a frequent basis.
  • Plumbers, electricians, telephone installers, maintenance and certain construction workers may be exposed to hantavirus contaminated materials when they enter areas such as crawl spaces under houses or abandoned outbuildings.
  • Clean-up activities involving dead rodents, feces, nesting materials and other potentially contaminated items have been associated with hantavirus cases in Washington state and nationwide.

Step 2: Minimize workers' risk for exposure

Efforts to prevent rodent infestations from occurring in the workplace can minimize or eliminate worker risk for exposure. Permanent workplaces must be constructed, equipped and maintained to restrict rodent entry and harborage.

Once evidence of rodent activity is observed, employers must institute an extermination program.

Follow precautions developed by Centers for Disease Control when applicable. These guidelines will tell you how to prevent rodent infestation, clean-up contaminated areas and how to safely handle rodents. Protective equipment, such as gloves and respirators, may be needed to safely perform tasks in addition to using disinfectants.

More help from L&I

For general information, call 1-800-423-7233.

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