Update and Commentary on Four Emerging Tick-Borne Infections: Ehrlichia muris-like Agent, Borrelia miyamotoi, Deer Tick Virus, Heartland Virus, and Whether Ticks Play a Role in Transmission of Bartonella henselae.

Emerging tick-borne infections continue to be observed in the United States and elsewhere. Current information on the epidemiology, clinical and laboratory features, and treatment of infections due to Ehrlichia muris-like agent, deer tick virus, Borrelia miyamotoi sensu lato, and Heartland virus was provided and critically reviewed. More research is needed to define the incidence and to understand the clinical and the laboratory features of these infections. There is also a growing need for the development of sensitive and specific serologic and molecular assays for these infections that are easily accessible to clinicians.