Medicine: Big Trouble with Tiny Ticks

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Call it the Great Impostor. Like rheumatoid arthritis, it painfully inflames knees and ankles. Sometimes it masquerades as heart disease, provoking arrhythmias so severe that a pacemaker may be required. It can strike the brain, inciting blinding headaches, memory lapses and even chronic depression. Muscular coordination can become so shaky that doctors suspect multiple sclerosis. Walt Dabney, 41, of Herndon, Va., suffered for more than two years with many of these symptoms and ran up $4,000 in medical bills before his problem was correctly diagnosed: he had Lyme disease, a bacterial infection spread by ticks. Says Dabney, chief ranger for the National Park Service: "I'm convinced that a lot of people are being treated for arthritis when they've been bitten by a tick."

The difficulty of diagnosing the ailment was a prominent topic last week at the third international conference on Lyme disease, in New York City. A second worrisome theme: the prevalence of the infection, not only in the northeastern U.S., where it was first diagnosed twelve years ago, but across the country and around the world. Researchers reported that the disease has now been found in at least 32 states and six continents, in part because doctors have become more adept at diagnosing it. Since 1980 there have been nearly 6,000 officially recorded cases in the U.S., but experts say the actual number is far higher. "If it weren't for AIDS," says Microbiologist Russell Johnson of the University of Minnesota, "it would be the No. 1 new disease facing us today."

Symptoms of Lyme disease were described in Europe a century ago, but it was not until 1975 that Rheumatologist Allen Steere, then at Yale, made sense of the malady. Steere investigated a group of children, in and around Lyme, Conn., who were suffering from a mysterious form of arthritis. He traced the outbreak to speck-size ticks of the genus Ixodes, carried mainly by mice and deer. In 1982 federal researchers isolated the culprit from the tick: a corkscrew-shaped bacterium, or spirochete, similar to the one that causes syphilis.

For about 70% of victims, the first sign is a rash that often looks like a bull's-eye -- white in the center and red on the outside. It erupts up to a month after the tick bite, and is sometimes accompanied by fever, stiffness and extreme lethargy. At this stage, the infection is easily cured with common antibiotics, like tetracycline. Left untreated, however, more serious symptoms may develop as the spirochete makes its way into the brain (18% of cases), the joints (57%) or the heart (10%). Correctly diagnosed, even these complications can usually be reversed with large doses of antibiotics.

Efforts to contain Lyme disease are under way. In an attempt to disrupt the tick's life cycle, Harvard researchers have developed cardboard tubes containing insecticide-treated cotton that attract nesting mice and keep them bug-free. Meanwhile, work has begun on a vaccine and a urine test that may provide earlier diagnosis than the current blood test. Until a vaccine is available, however, the best protection is wearing long pants tucked into socks when walking in brushy areas -- or even in the backyard.