A disorder called Lyme disease, which bears striking similarities to syphilis, is spreading across the world.
Although deaths from the infection are rare, complications that affect virtually every organ in the body--from the skin to the heart and brain--are not. Like syphilis, Lyme can be transmitted from an infected woman to her unborn child.
The specter of Lyme's invasion of every continent except Antarctica brought more than 400 scientists and physicians to New York in the fall for an international meeting on strategies for coping with a disease that was virtually unknown in the United States until a dozen years ago.
Lyme disease has has been identified in 32 of the 50 states, including in 50 of California's 58 counties, with the highest concentration of cases in Marin, Sonoma, Mendocino and Humboldt counties.
Were it not for AIDS, "Lyme disease would be what we are all worrying about," said Dr. Russell Johnson, a microbiologist at the University of Minnesota who is working to develop an improved diagnostic test for Lyme and a vaccine against it.
When the disease was first recognized and named, after an outbreak among children in Lyme, Conn., in 1975, it was shrugged off as an obscure form of arthritis spread by wood ticks and of far less public health significance than the better-known Rocky Mountain spotted fever and another Western tick-borne ailment called relapsing fever. Although no one knew what caused what was then known as "Lyme arthritis," a virus was suspected.
Today, Lyme is recognized by the federal Centers for Disease Control in Atlanta as the most prevalent tick-borne disease in the United States, and perhaps in the world. And its causative agent is now known not to be a virus, but a spirochete, a corkscrew-shaped germ 1/5,000 of an inch long called Borrelia burgdorferi.
The germ, named after its discoverer, Willy Burgdorfer, is closely related to Treponema pallidum, the bacteria that causes syphilis. But unlike syphilis, which is transmitted by sexual activity, Lyme is spread by infected ticks, which pick up the germ when they feed on mice and deer during their complex two-year life cycle.
One of the most maddening things about Lyme is its variety of symptoms. The classic hallmark is a rash, but unfortunately about one-third of all Lyme patients never develop that symptom.
Those who get the rash sometimes also develop flu-like symptoms, joint pains resembling arthritis, headaches or a combination of such symptoms. Making it even more difficult to diagnose is the fact that many patients fail to develop the antibodies that might help a physician pin down the disease.
At the New York meeting, Dr. Goran Stiernstedt of Sweden's Karolinska Institute said intermediate and late-stage Lyme has been confused with a number of other diseases, including multiple sclerosis, brain tumor, stroke, mental depression, alcoholism, personality change, anorexia and generalized skeletal pain.
Others spoke of misdiagnoses including Alzheimer's disease and, possibly, amyotrophic lateral sclerosis, better known as Lou Gehrig's disease. Adding to the confusion, recurrent Lyme can often manifest itself as facial palsy, forgetfulness and trouble in concentrating.
No wonder Lyme is coming to be known as "the new great imitator." The old great imitator, of course, was syphilis, which could recur after supposed cure in a wide variety of guises, including the dementia that eventually killed Al Capone.
Lyme usually responds, after varying lengths of time, to antibiotics such as penicillin, erythromycin, tetracycline, amoxicillin and the newer ceftriaxone. And it sometimes disappears without medication. But that is not to say it has been cured; often months or even years later, Lyme comes back again--as can syphilis--and in its recurrence often has more bizarre symptoms, such as more severe arthritis, and is harder to treat.
"I think there are a lot of older people running around with some form of arthritic or neurological problem that's really traceable to Lyme disease," said Dr. Robert S. Lane, a University of California, Berkeley, medical entomologist.
Lyme was first seen in this country in Wisconsin almost 30 years ago and in Sweden as early as 1909. Some public health experts think Lyme may have originated in the Old World and migrated to the New--an ironic repayment for syphilis, which was imported into Europe by early explorers of the Western Hemisphere.
Although there is still much to be learned about Lyme, researchers have determined that the two ticks that most commonly transmit the disease feed first on small mammals (most often mice) and then on deer.
If mice or deer are not available, the ticks can get sustenance from birds, dogs, raccoons, cattle, sheep, horses and probably other large and medium-sized mammals.