Hiking and Hantavirus: Know Before You Go


By Troy Lambert

By September 13, 2012 eight cases of Hantavirus Pulmonary Syndrome were confirmed, but it was too late for three of the victims. They were already dead. All the victims were infected while staying in the Signature Tent Cabins in Curry Village.

Hiking in the Seven Devils Wilderness in Idaho, I visited a lookout tower, one I try to visit every time we make the trip. On the door to the lower portion of the tower where there is a storage room, a forest service warning sign (you can see it on the door behind me in the photo) stated:

“Danger. Do not enter. Extreme risk of Hantavirus.”

devils towerPhoto Credit: the author, Troy Lambert

So despite my curiosity, and the fact i had been inside before, I kept out. Because I knew the risks, and I certainly wasn’t in need of shelter. But with the onset of cold temperatures and winter hiking, the temptation to enter old buildings will be much higher. So here are some things you need to know before you go.

Hatavirus InfographicPhoto credit: USC See the entire infographic here.

What to Watch Out For

The virus lives in rodent leavings, specifically feces and urine, and becomes airborne when nests are disturbed. Droplets containing the virus are then inhaled. The deer mouse is the most common carrier, but other rodents can spread the disease as well.

deer mouseThe Deer Mouse. Photo credit: publicdomainimage.com

Before entering any structure, look for the presence of rodents and rodent nests. Do not disturb leavings if you find them. Simple things like stepping on dried leavings can cause them to become airborne: but sweeping or brushing them away would be even worse.

If you do come into contact with rodent droppings, wash the exposed areas thoroughly and move to an open area with plenty of ventilation.

Early Symptoms

If you think you have been exposed. watch for early symptoms. The problem? The early symptoms can resemble the flu, or even simply soreness and fatigue common when you are hiking, especially in cold weather. They usually appear 1 to 5 weeks after exposure, so you could find yourself feeling just fine for awhile. According to the Centers for Disease Control, or CDC, these are what to watch for:

  • Fever
  • Headaches
  • Muscle Aches
  • Stomach Problems
  • Dizziness
  • Chills

Even if you suspect you may have been exposed, seek medical as soon as any of these appear..

Late Symptoms

Four to ten days after the onset, symptoms worsen to include cough and shortness of breath. Essentially, the victim’s lungs are filling with fluid, and it may feel like they are wearing a tight band around their chest. It quickly progresses to severe breathing issues and Adult Respiratory Distress Syndrome.

lungsPhoto Credit: wikimedia.com

Those experiencing these symptoms should immediately seek emergency medical care.



There is no cure for HPS, and no specific treatment. Early detection seems to improve the odds of survival, but essentially medical professionals treat the symptoms. Typically this means oxygen and mechanical breathing assistance in an intensive care unit. There has been some experimentation with ribavirin, but there is no proof it is effective.

The End Result

Hantavirus is fatal in 38% of cases according to the CDC. That’s nearly 2 in 5. Clearly the best solution is prevention. Remember:

  • Avoid rodent leavings, especially in enclosed spaces.
  • Don’t disturb rodent feces if you see it, and leave the area right away.
  • Don’t sweep or clean up.
  • Do be aware of early symptoms
  • Don’t ignore warning signs. Seek medical attention if you even suspect you have been exposed.

When hiking anytime, but especially in cooler temperatures, not all shelter is created equal, and some of it can be hazardous to your health. Before you go, know what to watch for. If you see signs and warnings, don’t ignore them. Your life could depend on it.

Troy is a freelance writer, editor, and author who blogs by day and writes suspense thriller novels by night. He is an avid hiker, cyclist and skier who lives, loves, works, and writes in Boise, Idaho. His blog posts tend to be lighter than his novels because his dog helps him write those. His work can be found at troylambertwrites.com and you can follow him on Twitter @tlambertwrites.


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The mission of Outdoor Sports Guide Magazine is to inspire and educate endurance athletes and outdoor enthusiasts in the Mountain West through well-written content on adventure, travel, gear, health, fitness, nutrition, industry news, profiles, and ski resort information.

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