From Our 2012 Archives
Third Death in Yosemite Hantavirus Outbreak
3 Deaths, 8 Cases as Warnings to Park's Summer Visitors Expand
By Daniel J. DeNoon
Reviewed by Louise Chang, MD
Sept. 7, 2012 -- A third person has died of hantavirus infection in this summer's outbreak at Yosemite National Park.
Two other park visitors now have become ill, bringing the total case count to eight.
Seven of the eight were infected after staying in the Boystown tents that are part of the Curry Village area of the park. But one of the new cases had no contact with Curry Village. That person stayed miles away in four of Yosemite's remote High Sierra tents used by hikers and horseback riders.
The hantavirus strain common to the Yosemite area is sin nombre virus. It's carried by deer mice. The animals' droppings, urine, and saliva contaminate dusty areas with virus. When the dust is disturbed, people breathe in the virus and become infected.
The National Park Service and park contractor DNC Parks & Resorts already sent emails and letters to people who stayed in the popular Curry Village tents from mid-June through August. They now are sending new emails and letters to those who stayed in the High Sierra tents and other areas. In all, about 22,000 park visitors have received the warnings.
The letters warn visitors to get immediate medical help if they have any flu-like symptoms. It could be a sign they're on the way to hantavirus pulmonary syndrome. Early treatment is the best way to avoid this serious, life-threatening illness.
Hantavirus illness begins one to six weeks after exposure to the virus. Early symptoms include feeling tired, fever, chills, and muscle aches. Half of patients also get headaches, nausea, vomiting, dizziness, and abdominal pain. Over the next four to 10 days, they begin to cough and feel short of breath. They soon have great difficulty breathing.
Different kinds of mice and rats carry different hantavirus strains in different parts of the U.S. Nationwide, about 20% of these rodents are thought to carry hantavirus.
When cleaning up after a rodent infestation, first be sure to eliminate living rodents and seal the area against new infestations. Disturbed areas and dead animals should be sprayed with disinfectant (one part bleach to nine parts water), left to sit for five minutes, and wiped up wet while wearing rubber or plastic gloves. Be sure to disinfect the gloves and wash your hands when you're done. Never sweep or vacuum up rodent droppings or rodent nests -- this can throw hantavirus-carrying dust into the air.
SOURCES: Yosemite National Park web site. CDC web site. California Department of Health web site. Scott Gediman, assistant superintendent for public and legislative affairs, Yosemite National Park.