Two people have died after contracting hantavirus during their stay in tent cabins at Yosemite National Park's Curry Village, according to news reports.
Two other people have also fallen ill with the disease. As a result, 1,700 former visitors have been alerted by park officials that they may have been exposed to hantavirus, the Associated Press reported.
The cabins have been sanitized to minimize the risk of contracting the rodent-borne disease, but "it's absolutely impossible to eliminate all risk," spokesman Scott Gediman told the AP.
Hantavirus, which is carried by rodents and spread to humans via droppings and urine, can be fatal, according to the Centers for Disease Control and Prevention. People can contract it by breathing air that has been contaminated by the virus-ridden droppings and urine, though it's not transmissible between humans.
Sin Nombre hantavirus is the cause of most hantavirus cases in the United States and Canada; deer mice carry this form, the CDC reported. There are also less common forms of hantavirus, such as the New York hantavirus, which is carried by the white-footed mouse, and the Black Creek hantavirus, which is carried by the cotton rat.
Hantavirus leads to hantavirus pulmonary syndrome. The condition starts out with flu-like symptoms -- like vomiting, muscle aches and fever -- but then can progress to serious symptoms like fluid in the lungs, cough with secretions, decreased efficiency of the heart and decreased blood pressure, the Mayo Clinic reported.
If the symptoms get bad enough, it can lead to lung failure, according to the A.D.A.M. Medical Encyclopedia. In fact, if the disease has reached the lungs, the prognosis is not good even among people who get treatment.
The CDC reported that 38 percent of people who contract hantavirus die.
If you experience symptoms after coming in contact with a rodent or if you've been in an area where there may have been rodents, it's important to seek immediate medical help. The CDC said that the earlier treatment is administered, the better.
Treatments for hantavirus pulmonary syndrome include a medicine called ribavirin, as well as using a breathing tube or machine and receiving oxygen, according to the A.D.A.M. Medical Encyclopedia.
So what can you do to protect yourself from hantavirus? Take measures to seal up your home so that you don't get rodents, by keeping things clean (and food- and scrap-free), setting traps, sealing holes and bleaching and disinfecting areas where rodents have been, according to the Mayo Clinic.
And as for avoiding it while you're out camping, the Idaho Central District Health Department recommends avoiding rodents or areas where you see rodents nesting, only staying in cleaned and disinfected cabins and tents, making your campsite far away from trash, avoiding sleeping on the bare ground and wearing protective clothing.