Northward Expansion ofAmblyomma americanum(Acari: Ixodidae) into Southwestern Michigan

Abstract

Amblyomma americanum (Linnaeus) (Acari: Ixodidae) (lone star tick) is an aggressive, generalist parasite that vectors numerous important human and animal pathogens. In recent decades its geographic range has expanded northwards from endemic regions in the southeastern and southcentral United States. In 2019 five questing A. americanum ticks, comprising two life stages were detected at one site in southwestern Michigan, satisfying one CDC criterium for an established population for the first time in recent history in the state. To better characterize the extent of emerging A. americanum, we conducted active surveillance (i.e., drag sampling) in summer 2020 throughout Michigan’s southern counties and detected one adult A. americanum from each of six widespread sites, including where they had been detected in 2019. A larger established population was identified at another site in Berrien County, which yielded 691 A. americanum comprising three life stages, and questing phenologies here were similar to that reported for other endemic regions. Statewide surveillance in 2021 revealed no A. americanum outside of Berrien County, but establishment criteria were met again at the two sites where established populations were first detected respectively in 2019 and 2020. These observations may represent the successful invasion of A. americanum into Michigan. Data from passive (1999–2020) and active surveillance (2004–2021) efforts, including a domestic animal sentinel program (2015–2018), are reported to provide context for this nascent invasion. Continued active surveillance is needed to help inform the public, medical professionals, and public health officials of the health risks associated with this vector.

Current and Future Habitat Suitability Models for Four Ticks of Medical Concern in Illinois, USA

“…The predicted A. americanum habitat for the historical climate closely matches reported occurrences within Illinois [ 23 , 34 , 75 ]. Currently, this species is most abundant in the southern portion of the state but is becoming increasingly more common in the north [ 24 , 79 , 80 ]. A. americanum ’s aggressive host-seeking and non-specific host preferences create an optimal dispersal scenario which allows this tick to travel long distances on meso-mammals and deer, as well as birds [ 81 ].…”

“…The greater U.S. Midwest is on the leading edge of tick and TBD expansion. Within the past decade, studies have documented the continued range movement of four ticks of medical and veterinary concern in this region including the blacklegged tick ( I. scapularis ) [ 21 , 22 ], lone star tick ( A. americanum ) [ 23 , 24 ], American dog tick ( D. variabilis ) [ 25 , 26 ], and Gulf Coast tick ( A. maculatum ) [ 19 , 22 , 27 , 28 ]. These range expansions have corresponded with an increase in reported TBD cases associated with these species including Lyme disease [ 29 ], ehrlichiosis [ 30 ], tidewater fever [ 27 ], and the newly documented Heartland virus [ 31 ].…”

Current and Future Habitat Suitability Models for Four Ticks of Medical Concern in Illinois, USA

“…Guerra et al (2002) IDPH 2022). Currently this species is most abundant in the southern portion of the state but is becoming increasingly more common in the north (Ma et al 2021;Rochlin et al 2022;Fowler et al 2022). A. americanum's aggressive host seeking and non-specific host preferences create an optimal dispersal scenario which allow this tick to travel long distances on meso-mammals and deer, as well as birds (Goddard and Varella-Stokes 2009).…”

“…The greater U.S. Midwest Is on the leading edge of tick and TBD expansion. Within the past decade, studies have documented the continued range movement of four ticks of medical and veterinary concern in this region including the blacklegged tick (Ixodes scapularis) (Rydzewski et al 2011;Lockwood et al 2018), lone star tick (Amblyomma americanum) (Springer et al 2014;Fowler et al 2022), American dog tick (Dermacentor variabilis) (Boorgula et al 2020;Martin et al 2022), and Gulf Coast tick (Amblyomma maculatum) (Lockwood et al 2018;Phillips et al 2020;Alkishe & Petersen 2022;Flenniken et al 2022). These range expansions have corresponded with an increase in reported TBD cases associated with these species including Lyme disease (Robinson et al 2015), ehrlichiosis (Johnson et al 2015), tidewater fever (Phillips et al 2020) and newly documented Heartland virus (Tuten et al 2020).…”

Current and Future Habitat Suitability Models for Four Ticks of Medical Concern in Illinois, USA

“…closely matches reported occurrence within Illinois(IDPH 2022). Currently this species is most abundant in the southern portion of the state but is becoming increasingly more common in the north(Ma et al 2021;Rochlin et al 2022;Fowler et al 2022). A. americanum's aggressive host seeking and non-specific host preferences create an optimal dispersal scenario which allow this tick to travel long distances on meso-mammals and deer, as well as birds (Goddard and Varella-Stokes 2009).…”