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. 2022 Sep 14;59(5):1646-1659.
doi: 10.1093/jme/tjac082.

Northward Expansion of Amblyomma americanum (Acari: Ixodidae) into Southwestern Michigan

Peter D Fowler  1 , S Nguyentran  2 , L Quatroche  2 , M L Porter  1 , V Kobbekaduwa  1 , S Tippin  3 , Guy Miller  3 , E Dinh  4 , E Foster  4 , J I Tsao  2   5
Affiliations

Northward Expansion of Amblyomma americanum (Acari: Ixodidae) into Southwestern Michigan

Peter D Fowler et al. J Med Entomol. .

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.

Keywords: Amblyomma americanum; Michigan; distribution; surveillance.

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Figures

Fig. 1.
Fig. 1.
Numbers of Dermacentor variabilis, Ixodes scapularis, Amblyomma americanum, and other species submitted annually to the Michigan Department of Agriculture (1999–2013) and Michigan Department of Health and Human Services (2015–2020). On average, 3.2% ± 1.7% SD of all ticks submitted annually were A. americanum. Data source: MiTracking- Michigan Environmental Public Health Tracking; no data are available for 2014.
Fig. 2.
Fig. 2.
Amblyomma americanum submitted annually to the Michigan Department of Agriculture (2009–2013) and the Michigan Department of Health and Human Services (MDHHS) from 2015 to 2020. Data source: MiTracking- Michigan Environmental Public Health Tracking. Numbers in each county represent the number of community- submitted A. americanum by county of residence. No data were available for 2014. *Human population heatmap for each county is given for reference based on 2020 census date (collated by Esri 2021) with lighter being lower population (less than 182,000) and darker being higher population (over 1.5 million).
Fig. 3.
Fig. 3.
Drag sampling effort by county (m2) from 2017 to 2021. Black dots mark field sampling sites. dots with circles mark sites where A. americanum were found. (A) Sampling effort for 2017, 2018, 2019, 2021; (B) Sampling effort for 2020 from 8 June to 23 July (See Table 1). The square marks the established population of A. americanum at Grand Mere State Park (detected in this study). The star marks a site sampled regularly as a reference for I. scapularis to ensure they are active regionally when sampling other sites. Only the first three visits for this site (i.e., during the nymphal host-seeking period) were included in the effort calculations for each year so as not to skew overall county effort.
Fig. 4.
Fig. 4.
Phenology of each questing life stage of (A) Amblyomma americanum and (B) Ixodes scapularis at Grand Mere State Park (Berrien County) from 11 June 2020 to 10 October 2020 (ended after 2 consecutive visits in the fall where no A. americanum were detected). See the square on the map in Fig. 2 for the location of the field site.
Fig. 5.
Fig. 5.
Photograph of a questing adult male Amblyomma americanum found by Burnley Traux and captured by Joseph Hinds on 17 May 2020 at Grand Mere State Park and originally submitted to iNaturalist. Photograph is reproduced here with permission from the photographer and represents the first record of A. americanum at this site.
See this image and copyright information in PMC

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References

    1. Allan, B. F. 2009. Influence of prescribed burns on the abundance of Amblyomma americanum (Acari: Ixodidae) in the Missouri ozarks. J. Med. Entomol. 46: 1030–1036. - PubMed
    1. Bacon, E. A., Kopsco H., Gronemeyer P., Mateus-Pinilla N., and Smith R. L.. 2021. Effects of climate on the variation in abundance of three tick species in Illinois. J. Med. Entomol. 59: 700–709. - PMC - PubMed
    1. Behravesh, C. B., Paddock C. D., Dahlgren F. S., Eisen R. J., and Springer Y. P.. 2016. Expanding range of Amblyomma americanum and simultaneous changes in the epidemiology of spotted fever group rickettsiosis in the United States. Am. J. Trop. Med. Hyg. 94: 35–42. - PMC - PubMed
    1. Black, H., Potts R., Fiechtner J., Pietri J. E., and Britten H. B.. 2021. Establishment of Amblyomma americanum populations and new records of Borrelia burgdorferi-infected Ixodes scapularis in South Dakota. J. Vector Ecol. 46: 143–147. - PubMed
    1. Bolte, J., Hair J., and Fletcher J.. 1970. White-tailed deer mortality following tissue destruction induced by lone star ticks. J. Wildl. Manage. 34: 546–552.

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