Lyme Disease Coinfections in the United States.

Lyme disease in North America is caused by infection with the spirochetal bacterium Borrelia burgdorferi and transmitted by Ixodes scapularis and Ixodes pacificus ticks. These ticks also have the potential to transmit a rapidly expanding list of other pathogenic bacteria, viruses, and parasites, including Anaplasma phagocytophilum, Babesia microti, deer tick (Powassan) virus, Borrelia miyamotoi, and the Ehrlichia muris-like organism. Coinfections with B burgdorferi and these other agents are often difficult to diagnose and may go untreated, and thus contribute significantly to patient morbidity and mortality from tick-borne infections.