Editor’s note – this article has been substantially updated and republished here. Please read and comment there. Thanks.
Lyme disease is an infectious disease caused by at least three species of bacteria belonging to the genus Borrelia. Of the three species, Borrelia burgdorferi is the main cause of Lyme disease in North America, whereas Borrelia afzelii and Borrelia garinii are more prevalent in Europe. The disease is named after the towns of Lyme and Old Lyme, Connecticut, where a number of cases were initially identified in 1975.
Borrelia is transmitted to humans when bitten by infected ticks belonging to a few species of the genus Ixodes, called “hard bodied” ticks. Although deer ticks, Ixodes scapularis, Ixodes pacificus, or Ixodes ricinus, are commonly considered to be the vectors for Borrelia infection, some of the other species in the Ixodes genus can transmit the disease. Lyme disease is the most common tick-borne disease in the United States.
The initial symptoms of Lyme disease include fever, headache, fatigue, depression, and a circular skin rash called erythema migrans (EM). If the Borrelia infection is not treated quickly, later symptoms may involve the joints, heart, and central nervous system. There is generally only one known treatment for the infection–antibiotics including doxycycline, amoxicillin, and cefuroxime. The symptoms usually disappear after antibiotic treatment.
From this rather straightforward disease, a whole cottage industry has arisen around the chronic Lyme disease myth – it claims that the Lyme disease is never really killed and it persists for months or years.