Distribution and Establishment of the Lone Star Tick in Connecticut and Implications for Range Expansion and Public Health

Abstract

In the United States, the lone star tick, Amblyomma americanum (L.) (Acari: Ixodidae), is an aggressive southeastern species whose range has reportedly been steadily expanding northward. The number of A. americanum specimens submitted to the Tick Testing Laboratory (TTL) at the Connecticut Agricultural Experiment Station (CAES) increased by 58% from the period of 1996-2006 (n = 488) to 2007-2017 (n = 773), mainly from Fairfield County in the southwestern corner of the state. The greatest numbers of A. americanum submissions to the CAES-TTL were from the City of Norwalk and a few adjacent municipalities. We also report the discovery of a large infestation of adult and nymphal lone star ticks detected on a dead male white-tailed deer, Odocoileus virginianus (Zimmerman) (Artiodactyla: Cervidae), on Manresa Island, Norwalk, in June 2017, indicating a long established, undetected population along the southwestern coast. A sample of nymphal and adult host-seeking A. americanum collected July 2017 from Manresa Island were tested and a proportion were positive for Ehrlichia chaffeensis, Ehrlichia ewingii, and Anaplasma phagocytophilum. The A. americanum tick and its associated disease pathogens are expected to become an increasing public health concern in southern New England.

The growing importance of lone star ticks in a Lyme disease endemic county: Passive tick surveillance in Monmouth County, NJ, 2006 – 2016

“…variabilis was slowly expanding its range in Maine, while passive surveillance programs in Connecticut, Massachusetts, and Ontario, Canada have identified A . americanum as an emerging vector in these areas [21, 59, 60]. Additionally, the presence of exotic Asian longhorned ticks ( Haemaphysalis longicornis ) in the United States was only detected after a resident submitted ticks to her local health department [61].…”

Determining Effects of Winter Weather Conditions on Adult Amblyomma americanum (Acari: Ixodidae) Survival in Connecticut and Maine, USA

“…In recent years, A. americanum has been expanding its range northward along coastal regions of the Northeast, establishing breeding populations in previously uninhabited areas [16][17][18][19]. It has been speculated that such populations are restricted to coastal areas, where winter weather conditions tend to be milder.…”

“…Amblyomma americanum is a nuisance tick species with aggressive host-seeking behavior, high population densities [15], and the known ability to overwhelm hosts [19]. In addition, their ability to cause human cases of ehrlichiosis, Bourbon virus infection, Heartland virus infection, southern tick-associated rash illness, spotted fever group rickettsia, tularemia, and red meat allergy makes them a species of concern [21, [32][33][34].…”

“…Breeding populations of A. americanum are currently established throughout Long Island, New York [16,17] as well as Prudence Island and smaller islands in Narragansett Bay, Rhode Island [17,18], and have been reported on Cape Cod and Martha's Vineyard, Massachusetts [17]. More recently, the first reproducing and established population in Connecticut was documented in Norwalk [19]. Their increasingly high densities in the Northeast in conjunction with their aggressive host-seeking behavior are cause for concern for host species, including humans.…”

Local and regional temporal trends (2013–2019) of canine Ehrlichia spp. seroprevalence in the USA

“…In humans, E. chaffeensis is the most commonly reported infection followed by E. ewingii, but sporadic infections with E. muris eauclarensis and "Panola Mountain Ehrlichia" have also been reported [11,12]. Changes in the number of Centers for Disease Control and Prevention (CDC)-reported confirmed and probable human ehrlichiosis cases [13] may be associated with the northward expansion of A. americanum and E. chaffeensis from their historical range in the southern USA [14], with newly established counties reported as far north as South Dakota and New Hampshire [15]. Trends for the other ehrlichiosis agents in humans and dogs are not known.…”