What is B. miyamotoi?
Borrelia burgdorferi is the predominant cause of Lyme disease in the US, with a number of ticks acting as vectors for the infection. B. miyamotoi is genetically similar to B. burgdorferi and has been detected in all of the ticks that are vectors for Lyme disease, including Ixodes scapularis. The presence of such bacteria is not new, but this is the first incidence of reported cases of human infection in the US. Ticks in Connecticut were found to be carrying B. miyamotoi back in 2001, with Russian cases of human infection with bacteria reported in 2011.
Diagnosing B. miyamotoi Infection
The study looked at three groups of patients living in Block Island and Prudence Island, Rhode Island, and Brimfield, Massachusetts between 1990 and 2010. Samples from these patients were tested using ELISA and Western Blot for antibodies to GlpQ protein, specific to B. miyamotoi and not reactive for B. burgdorferi. The bacteria was found to be present in 3.2% of cases of suspected Lyme disease in patients from southern New England, and B. miyamotoi was found in 21% of cases of patients presenting with a viral-like illness at a clinic in southern New York. Three patients were found to have antibody levels at least four times as high as those in convalescent samples, suggesting a recent infection with the bacteria. The patients found to be infected with B. miyamotoi were treated with doxycycline or amoxicillin.
Updating Lyme Disease Tests
These results suggest that inclusion of B. miyamotoi in the two-tier testing for Lyme disease is warranted, just as it is now included in testing panels in Russia, and in parts of Europe. Unlike the Russian cases, however, none of the patients in this study had compromised immune systems, also highlighting a need to consider the diagnosis of B. miyamotoi infection where symptoms of Lyme disease are present in otherwise healthy individuals.
Peter J. Krause, P.J., Narasimhan, S., Wormser, G.P., Rollend, L., Fikrig, E., Lepore, T., Barbour, A., Fish, D., Human Borrelia miyamotoi Infection in the United States, N Engl J Med 2013; 368:291-293.