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New Study Finds Many Appalachian Trail Hikers Are Unable To Identify Key Sign Of Lyme Disease


A hike on the AT can be a wonderful experience, but hikers need to be better informed about the risks and symptoms of Lyme disease. Photo by cbowns via Creative Commons and flickr.

Lyme Disease is a common and serious tick-borne illness that can be difficult to diagnose, and both early recognition of infection and prompt treatment are important. Unfortunately, a new study says many hikers on the Appalachian Trail are unable to recognize one of the key indicators that an individual may have contracted the illness.

The study, conducted by four health-care professionals, is being published in the journal Wilderness and Environmental Medicine, and the authors note, "Lyme disease is the most common vector-borne infectious disease in North America. With nearly 2,500 Appalachian Trail (AT) hikers entering the endemic area for as long as 6 months, exposure to the disease is likely."

The Appalachian Trail runs for nearly 2,200 miles from Maine to Georgia, and is "managed by the National Park Service, U.S. Forest Service, Appalachian Trail Conservancy, numerous state agencies and thousands of volunteers." Along the way, the route pass through several NPS areas, including Delaware Water Gap National Recreation Area, Shenandoah National Park, and Great Smoky Mountains National Park

Lyme Disease is Most Common in 13 States

There's plenty of magnificent scenery along the AT, and although there's no need to be paranoid about the risk, it is important for hikers to know that part of that route is through areas where Lyme disease is endemic. The Centers for Disease Control and Prevention (CDC) says about 300,000 cases of Lyme disease were diagnosed in the U. S. in 2012, and 95% of those cases were reported from 13 states in the Northeast and Upper Midwest, from Virginia to Maine and then westward to Minnesota.

Although awareness of Lyme disease by the public and medical professionals is improving, there are two key factors in effective treatment: early recognition by an individual that he or she may have been infected, and prompt medical attention. According to the recent study, both of these may be a challenge for hikers on the AT, especially those who are engaged in a long trip on the trail.

A successful hike of any distance on the AT or any similar trail requires both preparation and determination, and once they're embarked on a long trek'”especially a "thru-hike" of the entire trail, it would not be surprising for hikers to be determined to forge ahead despite not feeling quite up to par. When you're pushing your body to cover a lot of miles of trail every day, it's easier to shrug off a headache, muscle and joint aches, a stiff neck, fatigue, and even a fever as simply part of the physical price to be paid for a challenging hike.

Common Symptoms Can Make Diagnosis Difficult

It's the very general nature of those common symptoms of Lyme disease that make it so easy to overlook'”or misdiagnose'”and that makes the recognition of the single most distinctive indicator of this illness especially important. According to the CDC, more than 70% of patients diagnosed with Lyme disease have a red, expanding rash called erythema migrans (EM); this rash is by far the most common indicator of an infection. The rash may have a "bulls-eye" appearance, as shown in the photo below, or it may be uniformly red or reddish-blue. This link from LymeMD provides some additional details about the rash and other symptoms.

That information caused a group of medical professionals to ask an interesting question: If this distinctive rash is the most reliable indicator of Lyme disease, how many hikers on the AT would actually recognize that rash if they saw it? The answers obtained by the recent study weren't exactly encouraging.

During the project, 379 responses were collected from hikers "at three geographically separate locations at or proximate to the AT from June 2011 to May 2012." As part of the study, hikers were shown photographs of the rash typical of Lyme disease. Only slightly more than half (54%) recognized the rash and its significance. The study also provided one indication of the prevalence of the disease among hikers on the AT.

Why Spotting the Rash Is So Important

Six percent of the hikers in the study "had seen [such a rash] either on themselves or on another hiker while on the AT" and nine percent of the hikers stated that they had been diagnosed with Lyme disease by a healthcare practitioner. Of those diagnosed, only about a third had actually seen an embedded tick on their body, a further indication of the importance of the rash as a warning sign of an infection.

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An example of the "EM" rash typical of Lyme disease. Photo by jongarrison via Creative Commons and wikipedia.

Awareness of Lyme disease and other tick-borne illnesses is important for anyone who ventures into the out-of-doors, not just hikers on the AT, so this study offers a timely reminder for all of us as we look ahead to warmer weather.

The photo to the right is one example of the signature rash, which the CDC says "begins at the site of a tick bite after a delay of 3-30 days (average is about 7 days). Rash gradually expands over a period of several days, and can reach up to 12 inches (30 cm) across. Parts of the rash may clear as it enlarges, resulting in a 'bull's-eye' appearance. Rash usually feels warm to the touch but is rarely itchy or painful."

You'll find more examples of the rash on page 13 of a helpful CDC publication on tickborne diseases at this link.

Finally, keep in mind that perhaps 30% of patients don't display a rash, so if you have other symptoms and have been in areas where ticks occur, don't hesitate to check with your health care provider.

Prevention and Treatment

Some tips for prevention and some good news are offered by the CDC: "most cases of Lyme disease can be treated successfully with a few weeks of antibiotics."That said, this is not an illness to ignore; left untreated, this disease can lead to serious complications.

The CDC has prepared a number of useful materials in an on-line "toolkit" available at this link, including a Lyme disease prevention fact sheet for hikers. This information is well worth reviewing before your next outdoor trip.

So, don't hesitate to enjoy a hike on the AT or anywhere else in the country. Just use common-sense techniques to reduce risks of tick bites, remove ticks promptly if you find them on your body, keep your eyes open for signs of a possible problem, and get medical help when it seems appropriate. This is one situation where "rash decision" to see a doctor could be a very good thing!

Perhaps you've had experience with Lyme disease, or know someone who has? If so, perhaps you'd like to share where it was contracted, if that's known, and any other advice for your fellow Travelers.


Hi Jim, this is a nice reminder for hikers, so thanks for putting it together.

But there's one big piece of misinformation that's important to point out. The bullseye rash occurs in a minority of cases of erythema migrans (EM). Your article makes it seem as though all cases of EM rash have a bullseye and the two are synonymous. Not true. In fact, EM cases are most often uniformly red and without a bullseye appearance. The popular perception that an EM has to be bullseye continues to lead people to delay evaluation and time-sensitive treatment.

If you don't believe me, check out the John's Hopkins University Lyme Disease Research Foundation at

Thanks for the comment, podino4.

I'm certainly not a medical professional, and as your information indicates, even interpreting tips from various expert sources can be a challenge with this disease. I've edited the story to reflect your comment, and included the link your provided.

Good question!

Information from the CDC says "this disease does not occur nationwide and is concentrated heavily in the northeast and upper Midwest."  However, if you look at this link on their website, some cases have been reported in some western states, including California, Arizona and Nevada—and other tick-borne diseases are found in the West. So ... it pays to be vigilant about prevention, which includes checking people and pets carefully after outdoor activities, and removing any ticks promptly.

There is information on this subject on the CDC website from 1999, but a follow-up post from 2012 says that vaccine was "discontinued by the manufacturer in 2002, citing low demand. People who were previously vaccinated with the LD vaccine are no longer protected." I believe that last statement is because there wasn't enough data about how long protection by the vaccine lasted without a "booster" at intervals.

This article mentions trials which are underway on a new version of a vaccine.

Perhaps others with first-hand knowledge about the vaccine, or who are medical professionals, can offer some further information about the vaccine.

It is in Oregon and Washington. Maybe not epidemic levels of the east coast but it is definately here. When I was at the doctors in Portland I was stunned to see lot of people getting IV and I asked this patient what they were being treated for and it was Lyme. Seemed like a lot of people to me considering only  352  cases were reported. I think the number is higher than that. Let's hope John Hopkins

with the billion dollar research grant, successfully find a cure and fast.

I've always been cautionous just in general a group of us used to hike in the woods and run a long trail, no  no longer hike in the woods or run in the woods, too paranoid of getting Lyme after I saw the condition of the people that had chronic Lyme , it woke me up to what this is and what it looks like. Yikes!

I know  three people that have it , one is runner, an outdoorsy person, The other was hiking out in the wilderness, and the third person was hiking  at the foot  of the Cascade mountains. I read of  case where  a guy got it playing ball in central park. Guess where some of those dogs went for the weekend perhaps in the  Hamptons then back home .  Lyme  was found in San Franscisco park! My point being, that it is places you would not expect, spray on the flea tick spray, soon we will all be walking around with a flea collar! :)


The reason the reported numbers are low is that if Lyme is suspected, oft times it is treated as such with antibiotics and not tested to confirm. This was my case. After spending time in New Hampshire with countless contact with ticks, I developed painful symtoms consistent with Lyme. Now living in Louisiana, my Dr was not versed in Lyme symptoms and after my urging to consider Lyme based on symtoms and location, an antibiotic regime was prescribed which ultimately led to no more symptoms.

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