Bob Proudman, director of conservation operations for the Appalachian Trail Conservancy, said an outbreak of norovirus among trail hikers began somewhere around the Tennessee-North Carolina border about four weeks ago and is moving north with the hikers.
Norovirus has a 12- to 48-hour incubation period, lasts 24 to 60 hours and may cause severe diarrhea, vomiting and dehydration.
"You could say it's the most serious outbreak in AT history. There was one case of hanatavirus which is very serious, in 1990. It struck an Australian hiker and CDC (Centers for Disease Control and Prevention) got involved," he said. Hantavirus is a contagious disease spread by rodents.
Steve Clendenning, a military veteran, became seriously ill with norovirus April 28, while hiking near Erwin, Tenn. Clendenning is among 14 military veterans participating in this year's Warrior Hike, a program designed to help wounded veterans "walk off the war" by hiking the entire 2,185 miles of the AT, from Georgia to Maine.
Clendenning was ultimately hospitalized. His appendix was infected because of the disease and had to be removed, according to Warrior Hike. He resumed the hike, meeting up with the other Warrior hikers in Virginia on May 17.
Warning posters have been posted along the trail to let hikers know of the outbreak, which is passed between people, said Proudman. Food and surfaces can also become contaminated if in contact with a person carrying the virus.
Proudman said it is unclear how many cases of norovirus there have been so far. Two weeks ago about a dozen cases were reported in Shenandoah National Park in Virginia.
The problem, said Diane Woolard, epidemiologist with the Virginia Department of Health, is norovirus is not necessarily a reportable disease. While outbreaks of many cases are reported, these are most often in residential care facilities. A state or national park wouldn't be expected to report illnesses, she said.
Dr. Ram Nambiar, epidemiologist with the state Department of Health, said reporting in Pennsylvania is the same as Virginia. "It's just not reportable." He said the state would only be informed if there is a "cluster" of people who are infected. And like Virginia, it is generally in residential facilities.
Nambiar said good hygiene is key to controlling norovirus. "Good hand-washing hygiene is important," he said.
However, hikers on the trail, he said, don't have the luxury of hot water and soap to keep themselves as clean as people around their homes. And, he said, hand sanitizers do not combat norovirus. A bleach-and-water solution is needed to kill this particular virus, he said.
Nambiar said if local residents decide to take to the AT for a hike, they should pack a bottle of bleach water for cleaning.
For now, the ATC has issued advisories directing hikers away from certain camping areas in the south. The problem, however, said both epidemiologists, is that norovirus can still be contagious for three to 14 days after people have recovered.
For trail hikers, that means the virus that originated in the Tennessee/North Carolina border area will be hiking into southern Pennsylvania any day, if it hasn't already.
Nambiar said there really is no reason for local residents to become alarmed because few, if any, will be in physical contact with any of the hikers, and even if they are, he said just wash properly and don't let an infected person come in contact with a food source.
Signs are being posted along the Appalachian Trail south of Maryland. Signs read "A.T. shelters and privies may have been used by sick hikers" and information includes ways to "help prevent spread of highly contagious 'stomach bug'":
- Wash hands with soap and water.
- Treat all water. Use best "leave-no-trace" practices.
- (Alcohol-based) hand sanitizers may not be effective against the stomach bug.
- Stomach bug has a 12- to 48-hour incubation period, lasts 24 to 60 hours and may cause severe diarrhea, vomiting and dehydration.
- People with stomach bug may be contagious for three days to two weeks after recovery.