Hantavirus Pulmonary Syndrome

What is hantavirus pulmonary syndrome (HPS)?

HPS is a serious, often deadly, respiratory disease that has been found mostly in rural areas of the western United States.

The disease is caused by a virus carried by rodents and passed on to humans through exposure to urine, saliva, or droppings from infected animals.

How common is HPS?

Fortunately, HPS is a relatively rare disease. See HPS statistics in the United States since 1983 (when the disease was first recognized). Since 1983 to September 19, 2006, 453 cases has been reported in the United States. Out of the 453 cases, 45 (about 10%) cases were in California residents.

Does HPS occur in San Mateo County?

Yes, infected mice are found on a regular basis during disease surveys in San Mateo County. However, there have not been any human cases reported from this county.

What kinds of rodents carry hantavirus?

Wild deer mice in the genus Peromyscus are the primary carrier of the virus that causes HPS.

Deer mice are found in San Mateo. Since the types of mice that carry a hantavirus are difficult to identify, all wild rodents should be considered potentially infectious and should be avoided.

How is the virus spread?

People are exposed to hantavirus through the urine, saliva and feces of wild mice. The virus becomes airborne when rodent droppings or nests are stirred up, such as when a mouse infested building is swept. People can also become infected by touching the mouth or nose after handling contaminated materials or when food items become contaminated with mouse droppings. A rodent’s bite can also transmit the virus.

Hantavirus is not spread from person to person. You cannot become infected by being near a person who has HPS. Pets are not known to transmit the virus to people. The virus, which is able to survive in the environment, can be killed by most household disinfectants, such as Lysol, bleach, or alcohol.

The highest risk of contracting a hantavirus is from exposure to air-borne droplets from rodent droppings or secretions. Most cases have been acquired in rural and semi-rural settings where deer mice commonly invade human dwellings. Activities which pose the highest risk include:

  • Occupying or cleaning rodent-infested barns, sheds, or abandoned dwellings
  • Disturbing rodent-inhabited areas while hiking or camping
  • Living in or visiting areas where there has been an increase in the rodent population
  • Working in enclosed spaces infested with rodents

How can I protect myself when I clean up?

It is important to avoid creating airborne particles of dust and debris while cleaning. Creating airborne particles increase the risk of contact with HPS.

  • Ventilate the affected area the night before cleanup by opening doors and windows
  • Use rubber gloves and wear a half-mask air-purifying (or negative-pressure) respirator with a high-efficiency particulate air (HEPA) filter
  • Apply household disinfectants at a maximum recommended concentration to dead rodents, rodent droppings, nests, contaminated traps, and surrounding area and allow for at least 15 minutes contact time before removal
  • Clean the affected area with paper towels or a mop. DO NOT SWEEP OR VACUUM.
  • Double bag the disinfectant-soaked rodent and clean-up material (newspaper, paper towels, etc.) securely in plastic bags and seal
  • Before removing gloves, wash gloved hands in disinfectant, and then in soap and water. Thoroughly wash hands with soap and water after removing the gloves. Dispose of gloves and clean-up materials with other household waste.

More information: How to Clean Up After Rodent Infestations

What are the symptoms of HPS?

Symptoms of HPS usually appear within two weeks of infection but can appear as early as three days and as late as six weeks after infection.

First symptoms are general flu-like symptoms. However, the primary symptom of this disease is difficulty in breathing, which is caused by fluid build-up in the lungs and quickly progresses to an inability to breathe. Symptoms also include fever (101ºF–104ºF), headache, abdominal, joint, lower back pain, and sometimes nausea and vomiting.

If any combination of the symptoms described above, especially difficulty in breathing, appear after direct or indirect exposure to rodents, contact your doctor or public health clinic immediately and be sure to mention your exposure to rodents.