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Accident Prevention

Mouse Attacks


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RYAN SEWELL AND RYAN “Future” Roden, two friends from Texas, camped and climbed in Rifle Mountain Park, Colorado, for a week in late July. While there, they chased a deer mouse out of their car, thinking little of it at the time.

The boys headed to Boulder to climb in Rocky Mountain National Park and then drove on to Salt Lake City. On August 8, Sewell complained of feeling ill and a loss of appetite, but thought he was simply dehydrated from the altitude in RMNP or was having a small bout with food poisoning. On the 9th he had a fever and no appetite, and felt very fatigued. He went to University Medical Center in SLC. Not suspecting his condition would turn into full-blown Hantavirus Pulmonary Syndrome (HPS), doctors put him on an IV to re-hydrate him.

On Friday, August 10, Sewell’s father, Dr. Robert Sewell, insisted that Ryan be flown back home, where he was admitted to the hospital in Bedford, Texas. There, blood work ruled out both Rocky Mountain spotted fever and West Nile virus.

Sewell’s fever spiked to 104.9 degrees F later on Friday and a series of chest X-rays showed a rapid progression of fluid build-up in his lungs. His breathing became more and more labored. Events unfolded quickly. With evidence mounting, the infectious-disease doctor had blood work sent to test for HPS. By 6 p.m. on Saturday, Sewell was intubated and on a ventilator. Even with 100 percent oxygen piped to his lungs, Sewell barely held his blood-oxygen above critical levels. To compound the problem, his blood-clotting functions had become extremely abnormal. “The threat to his life was now both from respiratory failure and potential hemorrhage,” Dr. Sewell says. Ryan’s existence was hanging by a very core-shot rope.

It wasn’t until August 14 that Hantavirus was confirmed by the CDC as the source of his illness, but Sewell gradually came through with supportive therapy. Feeling better, Sewell actually went out bouldering on some easy problems five days after being released.

Upon learning of Ryan Sewell’s illness, Ryan Roden’s mother stopped him from leaving Miami for Ecuador and had him flown back to Texas for HPS testing. After testing negative and having no ill effects, he came in seventh place in the Male Juniors category at the World Youth Championships of climbing in Ibarra, Ecuador.

According to the infectious-disease specialists, there is no way to be certain that Sewell contracted HPS at Rifle Mountain Park, but the evidence pointing in that direction is strong. Colorado has several cases of HPS every year, according to the state’s Board of Health, and they are concentrated on the Western Slope, where Rifle is located. Also, there is no other time Sewell and Roden can recollect coming in contact with a known reservoir of the virus.

Contamination might have occurred when the boys chased the deer mouse out of their car. When frightened, deer mice urinate while fleeing, and according to the CDC, infection in most of North America generally happens when aerosolized deer-mouse urine or fecal matter is inhaled. It may also be transmitted if excrement gets on a person’s body and then that body part comes in contact with a mucous membrane.

Hantavirus can be deadly—the CDC reports a 38 percent mortality rate, though mortality rates tend to be higher if patients are hospitalized only after fluid has begun collecting in the lungs. As of July 2007, six states have reported 30 or more cases of HPS since 1993, when the virus was discovered: New Mexico (69), Colorado (49), Arizona (46), California (43), Texas (33) and Washington (30).

The virus is also stealthy due to the fact that its original signs and symptoms mimic those of a cold or the flu. Loss of appetite, fatigue, fever, and general malaise may point to HPS, if you think you may have come in contact with a contaminated vector. Deer mice can be almost anywhere (the CDC reports they can fit through a hole the size of a button), but areas with the greatest risk are seasonally closed or abandoned buildings, or any dwelling infested by mice. Sweeping out barns, cabins or warehouses are very high-risk activities.

There is no specific treatment for HPS. A patient with HPS will be intubated, placed on a ventilator with 100 percent oxygen and positive pressure breathing, and continuously monitored.


Campers like Sewell, Roden and much of the climbing population are at risk of being infected by HPS through contact with deer-mouse excrement. The best avoidance is never to give the mice any reason to come around and contaminate your kitchen area, vehicle, tent or food storage.

Keep your campsite clean and free of loose or open food. If you are sleeping in your vehicle, keep it as clean and unfriendly to mice as you can. Wash your hands frequently if you’ve been handling anything that has been gnawed on by a rodent; the saliva may be a vector as well. Dispose of food that shows signs of rodent break-in. Store food in mouse-proof containers.

In daily life, avoid sweeping out varmint-infested storage sheds, barns, garages or warehouses without first wetting down all excrement and nest-matter with a solution of one cup bleach for every gallon of water used. Wear a mask and gloves, and wash your hands after handling any materials that appear to have been contaminated.