Topical prophylaxis for Lyme disease after tick bite in a rodent model.

To determine whether infection with the Lyme disease spirochete (Borrelia burgdorferi) can be aborted by topical application of antibiotic to the site of tick attachment, individual infected nymphal deer ticks (Ixodes dammini) were permitted to feed on the ears of mice, and various antibiotics were applied to the feeding site at intervals after the replete infecting tick had detached. Infection in each mouse was determined by serology and by xenodiagnosis at 4 weeks after the bite of the infected tick. None of these mice became infected when antibiotic was topically applied to the site of tick attachment within 2 days after the spirochete-infected ticks had detached. In contrast, all nontreated and virtually all solvent-treated mice became persistently infected. Thus, persistent infection by the agent of Lyme disease can be aborted by appropriate topical application of antibiotic.