Recent work suggests that human infection with Borrelia miyamotoi may cause symptomatic illness. This bacterium is different from Borrelia burgdorferi, which causes Lyme Disease. Borrelia miyamotoi is one of several species that cause a relapsing fever type of illness. Borrelia miyamatoi is found in blacklegged (deer) ticks and transmitted by tick bite. Larvae, nymphs and adults of the blacklegged tick may all be infected because this pathogen is transmitted from adult females to their eggs and subsequent offspring (larvae).
A recent report (Gugliotta et al. 2013) in the New England Journal of Medicine, identified a patient with meningoencephalitis as a probable result of infection with Borrelia miyamotoi. A second report (Krause et al 2013) in the same journal also identified several patients with symptoms and serology that indicated infection causing illness had occurred.
In Wisconsin, studies have found that 0-8% of the nymphs of Ixodes scapularis may be infected with Borrelia miyamotoi (Barbour et al. 2009). Research suggests that the adults will have similar rates of infection. No human cases have yet been identified here; however, the occurrence of the pathogen in ticks suggests that these infections are likely happening without diagnosis.
Barbour A. et al. 2009. Niche partitioning of Borrelia burgdorferi and Borrelia miyamotoi in the same tick vector and mammalian reservoir species. American Journal of Tropical Medicine and Hygiene 81:1120-1131.
Gugliotta J et al. 2013. Meningoencephalitis from Borrelia miyamotoi in an immunocompromised patient. New England Journal of Medicine 368:240-245.
Krause PJ. et al. 2013. Human Borrelia miyamotoi infection in the United States. New England Journal of Medicine 368:291-293.