The Trail Companion

Late Winter 1999

Lyme Disease News

by Geoffrey Skinner

Lyme disease (LD), an infection caused by Borrellia burgdorferi, a type of bacterium called a spirochete, is one of the hazards facing anyone who spends time in the outdoors in California and Oregon, as well as many other parts of the country (the highest concentration of incidence is the Northeast states). LD is spread by the bite of the Western black-legged tick and is only one of a number of tick-borne illnesses that have been identified; fortunately most others, such as Rocky Mountain spotted fever, are rare in our area. Although not usually life-threatening, LD is an infection which can affect many parts of the body, causing skin inflammation in the early stages, then spreading to the joints, nervous system, and to a lesser extent, the organ system.
      Vaccines against LD made the headlines in 1998 when SmithKline Beechem's LYMErix™ gained FDA approval. A second vaccine, ImuLyme™ (manufactured by Pasteur Meriuex Connaught) is awaiting FDA approval. Both vaccines are based on recombinant Borrellia burgdorferi DNA and work to kill the spirochete from the tick before it enters the bloodstream.
      Another story on the LD front also made the news recently--Western fence lizard blood appears to contain a substance which cleanses the tick's store of spirochetes, preventing both infection in the lizard, and likely, in other hosts as well. The lizard is the preferred host for the juvenile Western black-legged tick; researchers had noted the relatively low incidence of LD in the West, where the lizard is abundant Only 5% of the Western black-legged ticks harbor the spirochete, compared to over 50% among black-legged ticks in parts of the Northeast. The blood substance may hold promise as a vaccine in the future after it is better understood.
      It is important to note that the vaccine is a preventative measure--it won't help someone who is already infected. If you have been bitten by a tick or notice tell-tale signs of a bulls-eye ring on your skin (which may be accompanied by mysterious flu-like symptoms), see your doctor immediately for treatment with antibiotics. Although the vaccines and lizards may reduce the chances of infection in our region, you should make every attempt to avoid tick bites. The best defense against tick bites is vigilant examination. Ticks tend to seek warm, moist skin such as armpits and scalp--if you spend time outdoors, particularly in the winter and spring months, check yourself often, even if you never notice anything crawling up your clothing or on skin.
      If you are interested in the new vaccine, The American Lyme Disease Foundation, Inc. provides the following guidelines (updated 12/16/98):

Who should receive the vaccine?

Certain individuals at risk of Lyme disease should consider receiving the vaccine, including those who:

live in Lyme disease-endemic regions (especially in rural or wooded areas)
engage in outdoor recreation (hiking, camping, fishing, and/or hunting)
have a high-risk occupation (i.e. one that requires an individual to spend most of his/her working day outdoors)
plan to travel or move to an endemic area.

Who should not receive the vaccine?

The vaccine has not been approved for those in whom it has not yet been tested. Therefore, certain groups excluded from the original study trials are not currently eligible for the vaccine. They include:

individuals with chronic arthritis, which can also be a symptom of Lyme disease and thus interfere with determining whether the vaccine works
pregnant women, who generally are not studied in research settings and for whom physicians should evaluate the risks and benefits of vaccination
children under the age of 15 (vaccine trials are underway for children under 15)

For additional information on LD and LD treatments, you may wish to visit the American Lyme Disease Foundation, Inc. website (from which much of the information in this article was adapted) at http://www.aldf.com.