Anaplasma phagocytophilum Detected in Ticks from Ohio, U.S.A.1

Abstract

In North America, human granulocytic anaplasmosis is caused by the bacteriumAnaplasma phagocytophilum (Ehrlichiaceae),which is primarily transmitted by the blacklegged tick, Ixodes scapularis Say (Acari: Ixodidae) (Dahlgren et al. 2011). The native range of I. scapularis has been expanding in recent years, with significant populations recently detected in Midwestern U.S. states such as Ohio (Wang et al. 2014). Ixodes scapularis is a vector of several pathogens including Borrelia burgdorferi (Spirochaetaceae), Borrelia miyamotoi, A. phagocytophilum, Babesia microti (Babesiidae), and deer tick virus (DTV) (Flavivirus) (a close relative to Powassan virus) that causes encephalitis (Soneshine et al. 2002). As the range of I. scapularis expands through Ohio, there has been an effort to document the prevalence of B. burgdorferi, the agent of Lyme disease (Wang et al. 2014). Lyme disease is the most commonly diagnosed vector-borne disease in the eastern United States (Rossi et al. 2015) under active surveillance. In contrast, little effort has been directed at documenting the presence ofA.phagocytophilum in the same vector, even though human granulocytic anaplasmosis can be fatal and I. scapularis has been documented feeding on small Ohio mammalian reservoir hosts for over a decade (Wilder & Meikle 2004). The entomology program at the U.S. Air Force School of Aerospace Medicine regularly conducts pathogen surveillance in ticks (e.g., Foley & Reeves 2014, Taylor et al. 2016). Our goal was to determine the presence and prevalence of A. phagocytophilum in I. scapularis from Ohio. All ticks were collected as part of the B. burgdorferi surveillance project across Ohio. The initial results of this survey were published by Wang et al. (2014) who only discussed the surveillance of B. burgdorferi, the agent of Lyme disease, and new records of I. scapularis. This study focused on the prevalence of A. phagocytiphilum, which was not considered by Wang et al. 2014). In total, 425 adult