Lyme Disease: A Whodunit Tale

Some medical advances begin with old-fashioned detective work. Lyme disease, which was unknown in this country prior to 1975 is a good example.  That fall, two mothers from Old Lyme, Connecticut convinced the state Department of Public Health and Yale University to explore a mysterious outbreak of cases of inflammatory arthritis among the town’s children, because they were unsatisfied with the explanations they had been given for the cause. The investigation that winter centered on thirty-nine children and twelve adults from Old Lyme, all of whom had developed painful swelling of one or more joints between June and September.

Clues in clinical histories

Although blood tests and physical exams of the affected people had not previously revealed any known cause for the painful, swollen joints, investigators noted that there were striking similarities in the patients’ histories. Especially notable was a peculiar spreading rash that appeared about a month prior to the development of the arthritis and resembled an archer’s bull’s eye target. The affected people also lived close to one another, all in heavily wooded areas. The researchers concluded that the area where the cases clustered and the time of year in which they occurred were both crucial clues to the mystery. They believed that the illness could be an unknown type of infection but would have to await the next disease “season” for confirmation of this theory.

More clues in old European medical literature

In the meantime, investigators began combing through European medical literature, where they discovered similar descriptions of rashes going back to 1909. Over time, the Europeans had named the skin lesion erythema migrans and associated it with an illness that was similar to the one being reported in Connecticut, although without the arthritis. Some European reports mentioned tick bites in conjunction with the rashes, as well as successful treatment with antibiotics. Back in Connecticut, the next summer produced thirty more cases of what was by then being called “Lyme arthritis,” which investigators now believed was some kind of infection transmitted during outdoor activity.

Figuring out the tick relationship

The next pieces of evidence came from field studies of ticks. The distribution of a particular type of tick called Ixodes scapularis (variously known as the blacklegged tick, deer tick, or bear tick) near Old Lyme matched the distribution of local arthritis cases. Tick autopsies conducted in New York on Shelter Island, another hot spot for this mystery arthritis, showed that most of the ticks carried a spiral-shaped bacterium called Borrelia burgdorferi. Blood tests on affected individuals for antibodies to this organism tied it to the clinical cases of arthritis. Over the next two decades, the explosion of the deer population carrying the tick made the disease more common and widely known.As knowledge about and experience with the new disease accumulated, Lyme arthritis was renamed Lyme disease.

Early  Lyme disease symptoms

Lyme disease symptoms include an early stage of fatigue, muscle and joint pains, swollen glands, and headaches and fever that begin days to weeks after the infected tick bite. These symptoms represent the immune system’s response to the bacterial invasion. If a bull’s eye rash at the site of a former tick bite is present, diagnosis is easy. If not, diagnosis depends on a clear history of a tick bite and on the development of antibodies to the organism, which usually occurs later than the first few weeks of the illness.

Later symptoms

Left untreated, some, but not all infected patients develop symptoms within the next few weeks to months after the infected tick bite. Symptoms include arthritis, nerve pains, facial nerve paralysis, heart palpitations, shortness of breath, and chest pains. An even less common late phase that can occur up to two years after an infected tick bite might include migrating joint pains, muscle aches, abnormal muscle movements, weakness, heart arrhythmias, and cognitive complaints such as memory problems. These symptoms are not well understood and may represent a combination of the body’s ongoing fight against persistent bacteria and an autoimmune response that they trigger.

Treatment

Treatment of Lyme disease with oral antibiotics, either doxycycline or amoxicillin, is usually curative. If an infected tick is attached for more than thirty-six hours (the least amount of time it takes for transmission of the infection) and was encountered in an area where more than 20 percent of the deer tick population carries Borrelia burgdorferi, most patients are given a prophylactic one-time dose of doxycycline. Otherwise, treatment with antibiotics for two to four weeks begins as soon as the diagnosis of Lyme disease is made. The earlier the treatment, the faster the disease responds and symptoms subside. Late-phase treatment of neurological, cardiac, or arthritic symptoms may require intravenous delivery of antibiotics over longer periods. Although rare cases of persistent symptoms after treatment exist, no study has yet shown enough benefit from very long-term antibiotic use to justify the potential adverse effects of such a treatment.

Prevention of tick bites

Prevention of Lyme disease is the best way to deal with the illness, and there are things you can do to protect yourself. In the states where most cases occur (the New England states and New York, New Jersey, Maryland, Virginia, Wisconsin, and Minnesota), be aware that ticks tend to cling to high grasses and shrubbery in areas where deer roam. By hiking in the center of paths, away from tall grasses and shrubs, and wearing protective clothing, such as long sleeves and pants, you can reduce the chances of a tick bite. Shirt tails should be kept tucked in at the waist, sleeves should be kept closed at the wrists, and pants cuffs should be kept tucked into socks at the ankles. Additionally, spraying with insect repellent containing 20 to 30 percent DEET can help.

Self-examination is very important after potential tick exposure

The type of tick that transmits Lyme disease is Ixodes scapularis. It may be either a six-legged, immature tick nymph the size of a poppy seed or the slightly larger, eight-legged mature tick. Both forms excrete an anesthetic in their saliva that prevents you from feeling their bite, so close examination of your body is necessary after potential exposure. Bathe within two hours of coming inside and do a full body exam, with the aid of a mirror, paying close attention to areas covered with hair. Inspect all gear, clothing, and pets for ticks, and tumble clothing in a dryer at high heat to kill any hidden ticks.

Tick removal

Should you find an attached tick on your body, to remove it place the tip of a clean, fine-tipped tweezer as close to the skin as possible and pull gently, in a straight line. Dispose of all ticks in a toilet or drown them in alcohol and then seal them in a plastic bag for disposal. Clean bites with alcohol or iodine. Because the transmission of an infection from a tick to a human requires thirty-six to forty-eight hours of attachment, ridding yourself of ticks in the first twenty-four hours is effective prevention. Longer attachments that occur in high-risk parts of the country merit a single dose of doxycycline within seventy-two hours of a bite. Otherwise, be alert for symptoms or a rash, and seek treatment as soon as possible if they occur.

Research continues

The detective work surrounding the unraveling of the Lyme disease mystery continues today in the laboratory. Now researchers tend to focus on the rare people who, despite receiving adequate antibiotic treatment after contracting Lyme disease, experience persistent, unexplained, or recurring symptoms. These people remain almost as much of a mystery to researchers today as the initial thirty-nine children and twelve adult with arthritis were to researchers in the mid-1970s.

Respond to Lyme Disease: A Whodunit Tale

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