Borrelia lonestari infection after a bite by an Amblyomma americanum tick

Erythematous rashes that are suggestive of early Lyme disease have been ass ociated with the bite of Amblyomma americanum ticks, particularly in the so uthern United States. However, Borrelia burgdorferi, the causative agent of Lyme disease, has not been cultured from skin biopsy specimens from these patients, and diagnostic serum antibodies usually have not been found. Borr elia lonestari sp nov, an uncultured spirochete, has been detected in A. am ericanum ticks by DNA amplification techniques, but its role in human illne ss is unknown. We observed erythema migrans in a patient with an attached A . americanum tick. DNA amplification of the flagellin gene flaB produced B. lonestari sequences from the skin of the patient that were identical to th ose found in the attached tick. B. lonestari is a probable cause of erythem a migrans in humans.