Treatment of Lyme disease

Since the diagnosis of Lyme disease is based primarily on clinical findings, it is often appropriate to treat patients with early disease solely on the basis of objective signs and a known exposure.

Several antibiotics are effective in the treatment of Lyme disease. The present drug of choice is doxycycline, a semisynthetic derivative of tetracycline. Even patients who are treated in later stages of the disease respond well to antibiotics. In a few patients who are treated for Lyme disease, symptoms of persisting infection may continue or recur, making additional antibiotic treatment necessary. Varying degrees of permanent damage to joints or the nervous system can develop in patients with late chronic Lyme disease. Typically these are patients in whom Lyme disease was unrecognized in the early stages or for whom the initial treatment was unsuccessful.

Prevention

Removing leaves and clearing brush and tall grass around houses and at the edges of gardens may reduce the numbers of ticks that transmit Lyme disease. A relationship has been observed between the abundance of deer and the abundance of deer ticks in some parts United States. Reducing and managing deer populations in geographic areas where Lyme disease occurs may reduce tick abundance.

CDC recommends the following for personal protection from tick bites and Lyme disease:

Avoid tick-infested areas, especially in May, June, and July.

Wear light-colored clothing so that ticks can be spotted more easily. Tuck pant legs into socks or boots and shirt into pants or ape the area where pants and socks meet so that ticks cannot crawl under clothing.

Spray insect repellent containing DEET on clothes and on exposed skin other than the face, or treat clothes (especially pants, socks, and shoes) with permethrin, which kills ticks on contact.

Wear a hat and a long-sleeved shirt for added protection.

Walk in the center of trails to avoid overhanging grass and brush.

After being outdoors, remove clothing and wash and dry it at a high temperature; inspect body carefully and remove attached ticks with tweezers, grasping the tick as close to the skin surface as possible and pulling straight back with a slow steady force; avoid crushing the tick's body. In some areas, ticks (saved in a sealed container) can be submitted to the local health department for identification.

Preventive antibiotic treatment with erythromycin or doxycycline to prevent Lyme disease after a known tick bite may be warranted.

Personal protective measures, such as repellent use and routine tick checks, are key components of primary prevention. Removing infected ticks within 48 hours of attachment can reduce the likelihood of transmission, and prompt antimicrobial prophylaxis of tick bites, although controversial, might be beneficial under certain circumstances. Exposure to ticks in yards, playgrounds and recreational areas can be reduced 50-90% through simple landscaping practices, such as removing brush and leaf litter or creating a buffer zone of wood chips or gravel between forest and lawn or recreational areas. Correctly timed applications of pesticides to yards once or twice a year can decrease the number of nymphal ticks 68-100%.

In addition to these interventions, several novel approaches to Lyme disease prevention are under investigation and may soon be available. These include bait boxes and "four-poster" devices that deliver acaricides to rodents and deer without harming them, and the use of biologic agents, such as fungi that kill Ixodes ticks.

Vaccines for Lyme disease

In 1998, the Food and Drug Administration licensed the LYMErix^TM vaccine against Lyme disease for human use. LYMErix^TM contains lipidated recombinant outer surface protein A (OspA) of Borrelia burgdorferi sensu stricto, the causative agent of Lyme disease in North America, adsorbed onto aluminum adjuvant. It was indicated for use in persons aged 15-70 years. Three doses of the vaccine are administered by intramuscular injection. The initial dose is followed by a second dose one month later and a third dose 12 months after the first. Vaccine administration should be timed so the second dose and the third dose are given several weeks before the beginning of the B. burgdorferi transmission season which usually begins in April.

The vaccine was targeted at persons at risk for exposure to infected vector ticks. This risk should be assessed by considering the regional distribution of the disease and the extent to which a person's activities place them in contact with ticks. A Lyme disease risk map (below) is available from CDC. Vaccination of persons with frequent or prolonged exposure to ticks in areas endemic for Lyme disease was touted to be an important preventive strategy. Recommendations for use of the LYMErix^TM vaccine were developed by the Advisory Committee for Immunization Practices of the CDC.

In February, 2002, the manufacturer of the FDA-approved LYMErix^TM vaccine withdrew it from the market, reportedly because of poor sales. However, several other effective preventive measures remain available to persons living in areas where the disease is endemic.