Hantavirus Pulmonary Syndrome (HPS)

Information prepared by California Department of Public Health:

Hantavirus Pulmonary Syndrome Found in Two California Residents(PDF, 166KB)  (August 2012)

The recent discovery of Riverside County mice found to be infected with “Sin Nombre” virus, the causative agent of hantavirus pulmonary syndrome (HPS), has prompted Dr. Ron Chapman, director of the California Department of Public Health (CDPH) and state public health officer, to remind Californians to take precautions to prevent exposure to the virus that causes HPS.

“Hantavirus pulmonary syndrome is a rare, but often fatal disease spread by rodents,” Chapman said. “The chances of getting the virus are greatest while entering or cleaning enclosed spaces where wild rodents have been present, particularly cabins, trailers and other buildings infested with rodents.”

CDPH’s Vector Borne Disease Section collaborates with county, state, and federal public health agencies to test for “Sin Nombre” virus infection in wild rodents as part of human case follow-up, regular surveillance, or scientific studies.

HPS is caused by a virus that individuals get through contact with the urine, droppings or saliva of wild mice, primarily deer mice. Breathing small particles of mouse urine or droppings that have been stirred up into the air is the most common means of acquiring infection. The illness starts with fever, headache, and muscle ache, and progresses rapidly to severe difficulty in breathing and, in some cases, death.

Since HPS was first identified in 1993, there have been 57 cases in California and 587 cases nationally. About 35 percent of HPS cases identified in California were fatal. 


Hantavirus pulmonary syndrome (HPS) is a deadly disease transmitted by infected rodents through urine, droppings, or saliva. Humans can contract the disease when they breathe in aerosolized virus. Rodent control in and around the home remains the primary strategy for preventing hantavirus infection.

 To prevent HPS, Dr. Chapman recommends the following: 

Avoid areas, especially indoors, where wild rodents are likely to have been present. Wear plastic gloves and spray areas contaminated with rodent droppings and urine with diluted bleach. Place the waste in double plastic bags, each tightly sealed, and discard in the trash. Wash hands thoroughly afterward.

Do not touch or handle live rodents and wear gloves when handling dead rodents. Spray dead rodents with diluted bleach and dispose of in the same way as droppings. Wash hands thoroughly after handling dead rodents.

Keep rodents out of buildings by removing stacked wood, rubbish piles and discarded junk from around homes and sealing any holes where rodents could enter. Keep food in tightly sealed containers and store away from rodents.

If there are large numbers of rodents present in a home or other building, contact a pest control service to remove them.

For additional information on preventing HPS, please view the information on the federal Centers for Disease Control and Prevention’s Web site