New England Journal of Medicine Human Borrelia miyamotoi Infection in the United States Jan 17, 2013 Borrelia miyamotoi, a spirochete that is genetically related to species of Borrelia that cause relapsing fever, has been detected in all tick species that are vectors of Lyme disease. It was detected in Ixodes scapularis ticks from Connecticut in 2001 and subsequently has been detected in all areas of the United States where Lyme disease is endemic. The first human cases of B. miyamotoi infection were reported in Russia in 2011. We now provide evidence of B. miyamotoi infection and of the prevalence of B. miyamotoi infection among people in the United States.