Standing, he pulled up the leg of his shorts to reveal a well-defined reddish spot on his upper thigh, about three inches at its widest, darker toward the outer edge.
'I've got a couple more,' he said, and proceeded to expose those to the rest of the class. 'They've been getting bigger,' he added.
Bob denied any knowledge of being tick bitten, but it looked like erythema migrans to me, the characteristic rash that announces Lyme disease in somewhere between 60 and 80 percent of patients. The rash may develop where the tick bit or anywhere else on the body, with a tendency to show up most often on thigh, groin, armpit and sometimes behind the knee. After it first appears, the rash grows, or 'migrates.' If erythema migrans emerges in the first week of the disease, the spots rarely grow to more than 2.5 inches across. Spots appearing two to four weeks later may reach eight inches across. The red rash typically feels warm and may cause a burning sensation, but seldom produces pain or itching.
Any more indications of illness? I inquired. 'Something like the flu,' Bob said, describing more of the early symptoms of Lyme disease-low-grade fever, headaches, unusual fatigue and muscle aches.
Infecting more than 15,000 North Americans annually, Lyme disease is the leading disease borne by carrier organisms, or vectors, in the U.S. Yet the illness remains widely overlooked. Often misdiagnosed or left untreated, it may resolve itself in the first month, but about half the cases will progress to more serious levels. Dubbed 'the great imitator,' Lyme disease mimics many common ailments. Physicians can easily draw the wrong conclusion about an infected patient's 'obvious' symptoms, ruling out Lyme disease and treating one of its imitated illnesses instead.
Early symptoms are often mild enough to be ignored. The rash doesn't always appear. And the ticks can go unnoticed, typically attaching themselves during the nymphal stage between May and August, when they take up less room than a poppy seed on your skin. 'Many of the worst cases of Lyme disease were contracted a decade ago when people were not as aware of the illness,' says David L. Weld, executive director of the American Lyme Disease Foundation. But missing an early diagnosis continues to be a grave problem, leading to debilitating headaches, neurological or cardiological complications and Lyme arthritis, which attacks the larger joints, particularly the knee.
I voiced my concerns to Bob and suggested a timely (in other words, immediate) visit to a physician. The doctor took a blood sample and tested for the corkscrew-shaped Borrelia burgdorferi, the spirochete that causes the most common tick-borne disease in the world. Bob was diagnosed: Lyme disease. The treatment was an antibiotic, amoxicillin, for four weeks. The cure was complete.
The most common carriers of Lyme disease are the Ixodes ticks: deer ticks in the East and Midwest, and black-legged ticks in the West. After hatching from an egg in the spring, the larva feeds once in summer on the first red blood source that passes by (mammal, bird or reptile), picking up the spirochete if its meal is an infected deer mouse or other small mammal. Going dormant in fall and winter, the larva molts into a nymph during its second spring, feeding several times its second summer and transmitting the bacteria to humans if any should happen along. Later in the summer, the nymph molts into an adult tick, which is active in late fall through early spring. Easy to spot and remove, adult ticks have less chance of transmitting Lyme disease to humans.
While ticks are the main source of transmission, Lyme disease infections are boosted significantly by secondary agents. The white-tailed deer provides a favorite base for ticks to launch their attacks and is probably the worst if most unlikely-looking culprit. Deer and tick populations tend to be directly proportional. Wooded areas and small towns chock-full of Bambis have thus become some of the worst nesting grounds for Lyme disease. On Long Island, the town of North Haven has been hit hard enough to win airtime on '60 Minutes.' With about 600 white-tailed deer in the town's two and a half square miles, it's estimated that half the residents have been infected with Lyme disease-though this has remained a dormant issue until recently.First isolated and named in Lyme, Connecticut, in 1975, Lyme disease has spread most quickly in the Northeast, upper Midwest and northern California, with substantial growth in the South. So you can relax on your intended trip to Europe or Asia, right? Wrong, notes Weld. 'You're at risk,' he adds, 'from a tick bite in all countries of the northern hemisphere!' And a similar syndrome occurs in Australia. Although experts agree that the disease has been with us since long before 1975, it was the evidence from the Connecticut outbreak that proved ticks as the vector.
Woody and grassy areas can be thick with ticks from May through September-with the bugs congregating especially in moist areas and shade. They habitually crawl around for a while, perhaps weeks, seeking a tasty place to feed. Blind or almost blind, all ticks spend the mobile parts of their lives going up. They crawl until bumping into a blade of grass, a bush, anything that provides access to a higher place. They'll wait at the tip of the grass or bush for a meal to pass by. Once on your body, ticks may not stop their meandering until they reach your scalp. Those that dig in along the way demonstrate a preference for dark, moist body areas such as behind the knee, the groin, around the waistline, under breasts, in armpits and behind the ears. They feast on your blood and drop off a couple of days to a week later. Along the way, they pass on bacteria through their saliva, so the earlier they're removed, the less the chance of transmitting enough to cause illness.
Tick checks, several times a day if you're active outdoors, are extremely important. If you wear light-colored clothing and tuck your pants into your socks, you stand a good chance of recognizing and removing the dark-colored tick before it reaches your skin. Once indoors, shower (which should remove loose ticks) and give yourself a close examination. Embedded ticks should be immediately unembedded. Never apply oil, petroleum jelly, heat or anything else to remove the embedded tick. With a pair of sharp-tipped tweezers, grasp the tick as close to your skin as possible. Slowly pull it straight out, and avoid squeezing it. Finally, scrub the area with alcohol or an antibiotic ointment.
The New England Journal of Medicine has reported that ticks attached for less than 48 hours rarely transmit Lyme disease. But the risk escalates rapidly after this time. Tests on animals have shown an 83 percent infection level after 72 hours, and 100 percent if a tick is allowed to feed to repletion-over 120 hours.
Two repellents have proved effective in keeping ticks off. DEET (N-diethyl-meta-toluamide), the active ingredient in most repellents, may be applied to the skin. The Wilderness Medical Society, a physician-oriented group, advises a concentration of DEET no greater than 35 percent. Permethrin, a spray repellent sold by Sawyer Products (800-940-4464), contains the active ingredient permethrin and works on clothing. Permethrin doesn't work on skin directly, and can cause a rash or burn. On clothing, however, it dries and actually kills ticks (and mosquitoes) on contact for up to two weeks. The long-lasting effect of permethrin will allow you to treat your clothes prior to many trips and leave the spray can behind.
Two long-awaited vaccines for Lyme disease have become a new source of excitement and possible relief-though they aren't available as yet. LYMErix, made by SmithKline and Beecham Pharmaceuticals, and ImuLyme, from Pasteur Merieux Connaught, have both tested favorably in research labs, though success rates still vary somewhat according to age. At present, three doses of vaccine have proven 90 to 100 percent effective in younger subjects. For unknown reasons, the vaccines have had slightly lower success rates with older subjects-currently only 75 percent for people over 60, though a 12-month booster has been shown to raise this level somewhat. Both companies are presently filing for licensing with the Food and Drug Administration-but market approval is still pending.
In the meantime, avoiding tick bites remains the best preventative, and in case of a bite, prompt treatment is essential. If you think you've got Lyme disease, see your physician as soon as possible. Antibiotics prevent problems 98 percent of the time. Treat it promptly, and 'the great imitator's' act is easily canceled.
For more information, you can contact the American Lyme Disease Foundation at (914) 277-6970 or the Centers for Disease Control and Prevention (CDC) at (888) 232-3228. Buck Tilton is director of the Wilderness Medicine Institute.
FromEscape(Aug. 1999). Subscriptions: $18/yr. (4 issues) from Box 462255, Escondido, CA 92046.