When people who have been treated for Lyme disease recover but later come down with its symptoms again, is the illness a relapse or a new infection?
The question has lingered for years. Now, a new study finds that repeat symptoms are from new infections, not from relapses.
The results challenge the notion, strongly held by some patients and advocacy groups, that Lyme disease, a bacterial infection, has a tendency to resist the usual antibiotic treatment and turn into a chronic illness that requires months or even years of antibiotic therapy.
The conclusion that new symptoms come from new infections is based on genetically fingerprinting the Lyme bacteria in people who have had the illness more than once, and finding that the fingerprints do not match. The result means that different episodes of Lyme in each patient were caused by different strains of the bacteria, and could not have been relapses.
