The California Department of Public Health released a health advisory notifying state residents that they have received reports of six cases of Hantavirus Pulmonary Syndrome as of Aug. 30 – in people who visited Yosemite National Park.
CDPH officials have been working with the National Park Service and the Centers for Disease Control and Prevention to investigate the cluster of cases in Yosemite and to reduce the risk of other visitors becoming ill from the virus, according to a statement.
The people diagnosed with HPS visited the park between early June and mid-July, including five people from California and one from Pennsylvania. Of those diagnosed, two have died, one is hospitalized but improving, and three have recovered. Of those infected, four stayed in the “signature cabins” of the Boystown area of Curry Village, one lodged in an unspecified area of Curry Village, and the last patient’s lodging is still unknown, according to health officials.
The tent cabins in the Boystown area have been closed indefinitely and the National Park Service staff issued alerts to all guests who stayed in the area between June 10 and Aug. 24.
The virus takes up to six weeks for the first symptoms to manifest. Humans catch the virus through contact with airborne particles from the urine, droppings or saliva of infected wild mice, primarily deer mice. Breathing such particles that have been stirred up into the air is the most common means of acquiring the infection. The illness starts one to six weeks after exposure with fever, headache and muscle aches. It progresses rapidly to severe difficulty in breathing, and in come cases, death.
Since the virus was discovered in 1993, there have been 63 cases in California, with 21 of them resulting in death.
Tips to avoid HPS while visiting wilderness areas:
• Avoid areas, especially indoors, where mice are likely to have been present.
• Keep food in tightly sealed containers and store away from mice.
• Keep mice out of buildings by removing stacked wood, rubbish piles, and discarded junk from around homes and sealing any holes where mice could enter.
• If you can clean your sleeping or living area, open windows to air out the areas for at least two hours before entering. Take care not to stir up dust. Wear plastic gloves and spray areas contaminated with rodent droppings and urine with a 10% bleach solution or other household disinfectant and wait at least 15 minutes before cleaning the area. 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 mice and wear gloves when handling dead mice. Spray dead mice with a disinfectant and dispose of them in the same way as droppings. Wash hands thoroughly after handling dead mice.
• If there are large numbers of mice in a home or other buildings, contact a pest control service to remove them.
A non-emergency phone line for questions and concerns related to hantavirus in Yosemite has been set up. Visitors with questions can call 209-372-0822. The phones will be staffed from 9 a.m. to 5: p.m. daily. For more on the virus, visit the California Department of Public Health’s advisory page on hantavirus.
