Hantavirus and Death Valley

In view of the nine recent confirmed cases of Hantavirus Pulmonary Syndrome (HPS) in Yosemite National Park, three of which resulted in deaths (updated statistics as of 9/14), I thought it was important to discuss the matter of Hantavirus and Death Valley.  It’s not a subject that gets brought up a lot or that many people wish to discuss, but it is a necessary discussion.  With the extensive amount of backcountry cabins in Death Valley, many of which have rodent problems, Hantavirus should be a genuine concern to park visitors who make use of them.  Hantavirus is caused by a virus that individuals get through contact with the urine, droppings or saliva of infected 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 one to six weeks after exposure with fever, headache, and muscle ache, and progresses rapidly to severe difficulty in breathing and, in some cases, death.

As far as Hantavirus in Death Valley, the park service is aware of the threat and they make every effort to warn visitors and keep them informed.  The park service has posted warning signs at backcountry cabins, but often these signs turn up missing, likely taken down by visitors who don’t want this information known.  If you are a visitor to a backcountry cabin, please DO NOT remove the Hantavirus warning signs, as it is unfair to other visitors who may make use of the cabins and are not aware of the potential threat to their health.  As far as I know, the rodents in the backcountry cabins have not been tested for Hantavirus.  However, the rodents around both Furnace Creek and Scotty’s Castle have been tested by the Vector-Borne Disease Section (VBDS) of the California Department of Public Health for Hantavirus and some of the tests came back positive.  At Scotty’s Castle, 32 cactus mice and 1 deer mouse were collected.  13 of the cactus mice (or 41%) showed evidence of Hantavirus infection.  Around the Furnace Creek and Cow Creek areas, 12 cactus mice were collected in total.  1 of the 8 cactus mice (or 12.5%) collected from Cow Creek showed evidence of Hantavirus infection.  At Wildrose Campground, 2 canyon mice were collected.  With all mice collected throughout Death Valley, all but 1 of the infected mice were cactus mice.  The risk of Hantavirus from cactus mice is unclear, so all necessary precautions should be taken.  Deer mice are known to carry and shed a Hantavirus that is infectious to humans.

It would be safe to say that all cabins with rodent presence and rodent droppings should be considered potentially contaminated with Hantavirus, and that would just about cover all of the cabins in the park.  Personally, I’m not sure if I have been to a backcountry cabin that did not have some kind of rodent presence either outside or inside of it.  When I first learned about this issue a couple of years ago, I decided to post warnings about it on my Panamint City trip report and backpacking report pages because of the high-profile cabins found there.  Anyone who has read my Panamint City trip report page knows that the Hantavirus issue is highlighted right at the top of the page, and you cannot read that page without thinking about the matter.  One of the issues with backcountry cabins such as those found in Panamint City is that they are not easy to properly clean and disinfect by backpackers in line with CDPH (California Department of Public Health) guidelines.  How many people are going to pack bleach and other cleaning items to bring with them on the long hike up?  Probably nobody.  I actually quit sleeping inside the Panamint City cabins a couple of years ago due to the Hantavirus risk (although I did make a one night exception to this in April of 2012 due to extreme tiredness).

When you are hiking in Death Valley, you can take the following steps to minimize the risk of catching Hantavirus (based in part on CDPH recommendations) —

  • If possible, avoid being around backcountry cabins, mining tunnels, and old structures, especially indoors where wild rodents are likely to have been present.  If there are large numbers of rodents in a cabin, mining tunnel, or other structure, stay out of them.
  • Avoid sleeping in cabins and instead sleep inside a tent that is pitched away from areas that rodents frequent.  Check the ground where you pitch your tent for any signs of rodent activity.
  • If you are backpacking and choose to sleep in a cabin or outside directly on the ground, keep food in tightly sealed containers and store away from rodents.
  • Help keep rodents out of cabins and structures by removing stacked wood, rubbish piles, and other debris from around cabins and sealing any holes where rodents could enter.
  • If you wish to clean your sleeping or living area in a cabin, 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 a particle respirator and spray areas contaminated with rodent droppings and urine with a 10% bleach solution or other household disinfectants 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 (or pack out and dispose of properly later). Wash hands thoroughly afterward.
  • Do not touch or handle live rodents and wear gloves when handling dead rodents. Spray dead rodents with a disinfectant and dispose of in the same way as droppings. Wash hands thoroughly after handling dead rodents.
  • Do not disturb, vandalize, or remove Hantavirus warning signs that are posted by the park service.  Respect your fellow hikers’ rights to be aware of issues that might affect their health.
  • When entering a backcountry cabin to check it out or sign into a log book, wear a NIOSH-approved particulate filtering facepiece respirator or other appropriate means of protecting your lungs.  Try to minimize the amount of time you spend inside the cabin.  It is not known if this extra precaution can help prevent Hantavirus, but it certainly can’t hurt.