Updated: March 11, 2005
Lyme disease is caused by infection with Borrelia burgdorferi, a spiral-shaped (spirochetal) bacterium carried by deer ticks and western black-legged ticks. The ticks are often infected by feeding on the blood of the white-footed mouse, the white-tailed deer, and various species of birds, though these animals do not spread the disease to humans.
Most (80% to 90%) of people infected with Lyme disease develop one or more red, slowly expanding “bulls-eye” skin rashes at the tick bite sites (these are called erythema migrans), often accompanied by fatigue, fever, headache, stiff neck, muscle aches, and joint pain.
If diagnosed early, Lyme disease can be treated successfully with antibiotics. If the disease is left untreated, some people will develop more serious health problems such as arthritis, problems with the nervous system, pain in the large joints, and rarely, heart problems.
Lyme disease was first recognized in the United States in 1975. The number of annually reported cases of Lyme disease in the U.S. has increased approximately 25-fold since national surveillance began in 1982; during 1993-1997, a mean of 12,451 cases annually were reported by states to the CDC, and the incidence is increasing. The disease is mostly found in the northeastern, mid-Atlantic, and upper north-central regions of the U.S., and in several areas in northwestern California. Lyme disease is the most common vector-borne (spread from one host to another through a carrier such as a mosquito, fly, louse, or tick) disease in the U.S.
In 1998, the Lyme disease vaccine, LYMErix, was approved for use in people 15 to 70 years old. However, the vaccine was removed from the market by the manufacturer (GlaxoSmithKline) in February 2002 due to lack of demand.
The majority of those immunized (about 70% of those age 15-70 years) experience no side effects. Of those who do have a side effect, most are mild and limited to the injection site, including soreness (in 24.1% of vaccine recipients) and redness and swelling (in less than 2% of vaccine recipients).
Approximately 3% of those immunized experience fever, chills, or a general sense of feeling unwell that lasts for one to two days.
Though concern has been raised regarding the potential for vaccine-induced arthritis in recipients with the HLA-DR4 gene, no serious reactions have been confirmed.