Surge in Anaplasmosis Cases in Maine, USA, 2013-2017.

Incidence of human granulocytic anaplasmosis is rising in Maine, USA. This increase may be explained in part by adoption of tick panels as a frequent diagnostic test in persons with febrile illness and in part by range expansion of Ixodes scapularis ticks and zoonotic amplification of Anaplasma phagocytophilum.