Science / Medicine : Lyme Disease: : Focus on a Mysterious ‘Imitator’
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.
Immature ticks pick up the germ while partaking of the first of three blood meals they consume during their lifetime. The first blood meal is usually taken from a rodent, and if the rodent is infected with the germ, the immature tick becomes a carrier. The germ proliferates as the tick matures and enters the second, or nymph, stage of its life cycle.
It is when the nymph takes its second blood meal, often from a human, that infection most often occurs. The nymphs are quite small, and frequently victims do not even know they have been bitten.
Two related Ixodes tick species, I. dammini in the East and I. pacificus in the West, account for most of the Lyme disease in the United States.
Although originally thought to be a disease suffered mostly by children, Lyme is now known to attack people of all ages. Among its victims are Victor Wouk, 68, brother of novelist Herman Wouk, and Victor Wouk’s wife, Joy, who contracted the disease in 1987 as a result of Ixodes tick bites. A Connecticut baby was born with the disease in 1985; his mother was bitten during her pregnancy.
Alan B. MacDonald, a pathologist in Southampton, N.Y., and Christine Williams, a pediatrician at New York Medical College in Valhalla, N.Y., say prompt antibiotic treatment of pregnant women with Lyme disease will prevent fetal deaths. But they are not sure what role, if any, Lyme may play in causing birth defects.
Lyme is concentrated in three areas in the United States: along the Atlantic Seaboard from north of Boston to eastern Virginia, in southeastern Minnesota and western Wisconsin, and along the California coast north of San Francisco.
In 1980, when the Centers for Disease Control started studying the incidence of Lyme disease in the United States, doctors in only seven states--Connecticut, Wisconsin, Massachusetts, New Jersey, Minnesota, New York and Rhode Island--had seen more than one case of the disease. (Five cases that occurred in Northern California between 1978 and 1980 were not reported to the CDC).
Today, the same seven states list most of the cases. But by the end of 1986, California had moved into fifth place on the CDC’s list, with 107 cases, behind only New York, Connecticut, Massachusetts and New Jersey. The CDC’s national total for 1986 was about 1,400, but experts agree that Lyme is grossly under-reported and that last year’s actual total was probably more like 6,000.
According to Berkeley’s Lane and Dr. Paul Lavoie, a physician at San Francisco’s Pacific Presbyterian Medical Center who collaborates with Lane on Lyme research, Lyme disease in California is concentrated in Marin, Sonoma, Mendocino and Humboldt counties. As is the case elsewhere, symptoms can appear at any time of year, but the peak season for onset is from late spring through mid-summer.
Despite the dramatic rise in the number of Lyme cases in California (from 11 in 1983 to 107 in 1986), the disease appears to be more widespread in the East.
A reason for this difference may be that Ixodes pacificus, the Western Lyme tick, may be a less hospitable host for the germ than its Eastern cousin, Ixodes dammini. Sixty percent or more of all dammini ticks trapped and dissected by scientists have B. burgdorferi germs in the gut and salivary glands, compared to about 1% to 6% in the pacificus ticks found in California.
Efforts to find a definitive treatment for Lyme have been unsuccessful for a number of reasons. Little is known about the nature of the germ that causes it. And the infection does not confer lasting immunity after one attack, as with diseases such as measles and polio. The body develops antibodies to the Lyme germ, but these give little or no protection against future attacks.
Even if a victim is not reinfected, Lyme’s propensity to recur in an apparently recovered patient makes it impossible to be sure that the disease has been cured. Further, every time it recurs, it is more difficult to treat.
Lacking absolute cures or reliable vaccines, experts agree that prevention is the best hedge against the disease.
“Wherever there are mice and deer, there is likely to be Lyme disease,†Minnesota microbiologist Johnson said. This suggests that Lyme is more likely to be contracted in the country than in the city and that ticks that transmit Lyme are more likely to be encountered in underbrush than on closely mowed lawns and trimmed shrubbery. It also suggests that when people go into areas where Lyme is known to occur, they ought to dress appropriately and examine themselves afterward for ticks.
