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Amblyomma americanum
Amblyomma americanum
Amblyomma americanum
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Northeastern water tick
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Ixodida
Family: Ixodidae
Genus: Amblyomma
Species:
A. americanum
Binomial name
Amblyomma americanum
Red indicates where the species is normally found; Blue indicates other locations where the species has been reported
Synonyms

Acarus americanus Linnaeus, 1758

Amblyomma americanum, also known as the lone star tick, northeastern water tick, turkey tick, and cricker tick,[2] is a type of tick indigenous to much of the eastern United States and Mexico that bites painlessly and commonly goes unnoticed, remaining attached to its host for as long as seven days until it is fully engorged with blood. It bites aggressively, and its larvae may transfer themselves to skin from discarded clothing that is put back on.[3][4] The sexually dimorphic adult female lone star tick bears a silvery-white, somewhat star-shaped spot near the center of the posterior portion of its dorsal shield (scutum); adult males conversely have varied white streaks or spots around the margins of their shields.[3][5]

It is to this spot, not to Texas, that A. americanum owes the name lone star tick,[6][7][8] while it owes the name turkey tick to the wild turkeys that are a common host in its immature stages in some Midwestern U.S. states.[5] It is the primary vector of Ehrlichia chaffeensis, which causes human monocytic ehrlichiosis, and Ehrlichia ewingii, which causes human and canine granulocytic ehrlichiosis.[9] Its bite may also cause a human to develop alpha-gal syndrome, an allergy to non-catarrhine mammalian meat. Other disease-causing bacterial agents isolated from lone star ticks include Francisella tularensis, Rickettsia amblyommii, and Coxiella burnetti.[10]

The distribution of the lone star tick (Amblyomma americanum) in the United States

Range and habitat

[edit]

The lone star tick is widely distributed across the East, Southeast, and Midwest United States.[3][11] It lives in wooded areas, particularly in second-growth forests with thick underbrush, where white-tailed deer (the primary host of mature ticks) reside.[5][11][12] Lone star ticks can also be found in ecotonal areas (transition zones between different biomes) such as those between forest and grassland ecosystems.[11][12] The lone star tick uses thick underbrush or high grass to attach to its host by way of questing, that is, climbing up a blade of grass or to the edges of leaves, stretching its front legs forward, and—in response to stimuli from biochemicals such as carbon dioxide, heat, and vibration from movement—mounting a passing host as it brushes against the tick's legs.[13] Once attached to its host, the tick will move around and select a preferred feeding site.[5]

The tick has also been reported outside of its range in Canada, in areas of Southern Ontario, including in London, Wellington County, and the Region of Waterloo.[14]

Development

[edit]
Development of the lone star tick (A. americanum)

The tick follows the normal developmental stages of egg, larva, nymph, and adult. It is known as a three-host tick, meaning that it feeds from a different host during each of the larval, nymphal, and adult stages. The lone star tick attaches itself to a host by way of questing.[15] The eggs are laid on the ground, hatch, and the larvae wait for or actively seek a host (questing behavior). A larva feeds, detaches from its host, molts into a nymph when on the ground, and quests by crawling on the ground or waiting on vegetation. The nymph feeds and repeats the same process as the larva, but emerges having developed the anatomy of either an adult female or male. Adults quest similarly to nymphs. The female attaches only to a species of host for reproduction. The female engorges on blood, expanding greatly, then detaches and converts the blood meal into eggs, which are laid on the ground. Females of large species of Amblyomma engorge to a weight of 5 g and lay 20,000 eggs. The female dies after this single egg-laying. The male takes repeated small meals of blood and attempts to mate repeatedly whilst on the same host. Feeding times for larvae last 4–7 days, nymphs for 5–10 days, and adults for 8 to 20 days. The time spent molting and questing off the host can occupy the remainder of 6 to 18 months for a single tick to complete its lifecycle. The lifecycle timing is often expanded by diapause (delayed or inactivated development or activity) in adaptation to seasonal variation of moisture and heat. Ticks are highly adapted for long-term survival off the host without feeding and can extract moisture directly from humid air. However, survival is greatly reduced by excess heat, dryness, and lack of suitable hosts to which to attach. Survival on the host is also greatly reduced by grooming and by hypersensitive immune reactions in the skin against the feeding of the ticks.[citation needed]

Hosts

[edit]

The lone star tick is an aggressive, generalist feeder; it actively pursues blood meals and is not specific about the species of host upon which it feeds.[5] As already mentioned, A. americanum requires a separate animal or human host to complete each stage of its life cycle.[10] The lifecycle begins when the blood-engorged adult female tick drops from her host, depositing around 5,000 eggs a few days later, once she has reached a safe and suitable location, such as in mulch or leaf litter.[5] After an incubation period, larvae hatch from their eggs and undergo a quiescent (resting) period; this is followed by the pursuit of a host via questing.[5] After feeding for one to three days, the blood-engorged larva dislodges from its host to digest its blood meal and molt into a nymph. The nymph follows this same pattern, attaching to a new host via questing and dropping from the host after its blood meal to molt into an adult tick. The female adult tick dies shortly after depositing her eggs.[5]

Larval lone star ticks have been found attached to birds and small mammals, and nymphal ticks have been found on these two groups, as well as on small rodents.[5] Adult lone star ticks usually feed on medium and large mammals,[10] and are very frequently found on white-tailed deer.[4] Lone star ticks also feed on humans at any stage of development.[4]

Vector

[edit]

Like all ticks, it can be a vector of diseases including human monocytotropic ehrlichiosis (Ehrlichia chaffeensis), canine and human granulocytic ehrlichiosis (Ehrlichia ewingii), tularemia (Francisella tularensis), and southern tick-associated rash illness (STARI, possibly caused by the spirochete Borrelia lonestari).[16] STARI exhibits a rash similar to that caused by Lyme disease, but is generally considered to be less severe.[citation needed]

Though the primary bacterium responsible for Lyme disease, Borrelia burgdorferi, has occasionally been isolated from lone star ticks, numerous vector competency tests have demonstrated that this tick is extremely unlikely to be capable of transmitting Lyme disease. Some evidence indicates A. americanum saliva inactivates B. burgdorferi more quickly than the saliva of Ixodes scapularis.[17] Recently the bacteria Borrelia andersonii and Borrelia americana have been linked to A. americanum.[18][19]

In 2013, in response to two cases of severe febrile illness occurring in two farmers in northwestern Missouri, researchers determined the lone star tick can transmit the heartland virus.[20] Six more cases were identified in 2012–2013 in Missouri and Tennessee.[21]

Meat allergy

[edit]
Main article: Alpha-gal allergy

The bite of the lone star tick can cause a person to develop alpha-gal meat allergy, a delayed response to nonprimate mammalian meat and meat products.[22][23] The allergy manifests as anaphylaxis—a life-threatening allergic reaction characterized by constriction of airways and a drop in blood pressure.[22] This response is triggered by an IgE antibody to the mammalian oligosaccharide galactose-alpha-1,3-galactose (alpha-gal).[24] A study published in 2019 discovered alpha-gal in the saliva of the lone star tick.[25][26] As well as occurring in non-primate mammals, alpha-gal is also found in cat dander and in the drug cetuximab.[27][24] Allergic reactions to alpha-gal usually occur 3–6 hours after consuming red meat, unlike allergic reactions to other foods, whose onset following consumption is more or less immediate, making it more difficult to identify what caused the reaction.[22] Skin tests with standard meat test solutions are unreliable when testing for alpha-gal allergy, whereas skin tests with raw meat and/or pork kidney are more sensitive. Specific tests for determination of IgE to alpha-gal are available.[28]

See also

[edit]
  • Ticks of domestic animals
  • Surendra RS; Shahid Karim (2021). "Tick Saliva and the Alpha-Gal Syndrome: Finding a Needle in a Haystack". Frontiers in Cellular and Infection Microbiology. 11. doi:10.3389/fcimb.2021.680264. PMC 8331069. PMID 34354960.
  • Surendra RS; Choudhary S; Vorobiov J; Commins SP J; Shahid Karim (2024). "Tick bite-induced alpha-gal syndrome and immunologic responses in an alpha-gal deficient murine model". Frontiers in Immunology. 14. doi:10.3389/fimmu.2023.1336883. PMC 10882631. PMID 38390396.

References

[edit]
[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Amblyomma americanum

View on Grokipedia
from Grokipedia
Amblyomma americanum, commonly known as the lone star , is a of hard-bodied in the , widely recognized for its role as a vector of multiple tick-borne diseases in . Adult females are distinguished by a single iridescent white or cream-colored spot on their reddish-brown , while males are smaller and darker with ornate patterns. This three-host completes one generation per year, with larvae, nymphs, and adults actively seeking hosts across seasons. The lone star tick is primarily distributed across the eastern, southeastern, and south-central , with established populations from to the Atlantic coast and expanding northward into the Midwest and Northeast due to favorable habitats and host availability. It thrives in wooded, brushy, or grassy areas, particularly those with , which serve as key hosts for adults. Overwintering nymphs contribute to its persistence in northern ranges, up to coastal . A. americanum is an aggressive human-biting tick that transmits several pathogens, including Ehrlichia chaffeensis and Ehrlichia ewingii, causative agents of human ehrlichiosis. It is also associated with (), (STARI), and Heartland virus. Additionally, bites from this tick can induce , an allergic reaction to the carbohydrate alpha-gal found in , through sensitization via tick saliva. The tick's life cycle involves four stages—egg, , , and —with each parasitic stage feeding on a different host, ranging from small mammals and birds for larvae and nymphs to larger animals like deer, dogs, and humans for adults. Larvae peak in activity from June to August, nymphs from April to August, and adults from March to May, making year-round encounters possible in warmer regions. Its generalist feeding behavior and rapid questing enhance its significance.

Taxonomy and morphology

Taxonomy

Amblyomma americanum belongs to the domain Eukaryota, kingdom Animalia, phylum Arthropoda, class Arachnida, subclass Acari, order Ixodida, family Ixodidae, genus Amblyomma, and species americanum. This hard tick species is classified within the Ixodidae family, which encompasses over 700 described species of ixodid ticks known for their three-host life cycles and economic importance as vectors of disease. The species was first described by in 1758 under the Acarus americanus, later reclassified into the as understanding of evolved. Synonyms include the homotypic Haemalastor americanus (Kollar, 1832). Common names for A. americanum include the lone star , reflecting the distinctive white spot on the , as well as turkey and northeastern water in some regional contexts. Phylogenetically, A. americanum forms a monophyletic group within the Amblyomma and is closely related to the Amblyomma cajennense species complex, with A. maculatum serving as a to this based on analyses of mitochondrial and nuclear markers. Genetic studies using markers such as the mitochondrial 16S rRNA have revealed population divergence across North American ranges, indicating regional genetic structuring despite . Recent taxonomic confirmations have utilized molecular markers, including 16S rRNA sequencing, to verify the ' distinct status and differentiate it from invasive congeners like members of the A. cajennense complex that may overlap in distribution. These approaches have supported the stability of A. americanum's , with no major revisions since its placement in the Amblyomminae subfamily.

Physical characteristics

Amblyomma americanum exhibits distinct morphological features across its life stages, characteristic of the genus Amblyomma, with ornate patterns serving as key identification markers in adults. Adult females are reddish-brown and measure 3.0 to 5.6 mm in length when unfed, expanding dramatically to up to 15 mm when engorged with blood. Their scutum, a sclerotized dorsal shield, covers only the anterior one-third to half of the body and features an ornate pattern with a prominent iridescent white, star-like spot located posterior to the eyes, along with white enamel-like markings on the festoons—rectangular posterior extensions of the body. The mouthparts are long and visible from the dorsal view, including a hypostome with 3/3 dentition, consisting of three rows of three teeth each, which aids in host attachment. Adult males are slightly smaller, ranging from 3.2 to 5.0 mm in length, and also reddish-brown, but their extends over the entire dorsal surface, displaying white streaks across the body and marginal spots, with similar ornate white markings on the festoons. Like females, males possess long mouthparts with a 3/3 hypostome and lack significant engorgement. Sexual dimorphism is pronounced in A. americanum, with females being larger and having a partial that allows abdominal expansion during feeding, whereas males are fully sclerotized dorsally for mobility and mating. This difference in scutum coverage highlights the species' to reproductive roles, with females showing a visible genital aperture dorsally. Nymphs measure 1.5 to 3.0 mm and are light brown to reddish-brown, lacking the white markings of adults but retaining similar shorter mouthparts with toothed hypostomes; they possess spiracle plates posterior to the fourth pair of legs and leg structures adapted for questing. Larvae are even smaller, at 0.6 to 1.0 mm, pale in color, hexapod with six legs, and feature very short toothed mouthparts, spiracles, and basic leg tarsi without ornate patterns. Sensory structures in A. americanum include Haller's organ on the tarsus I of the first pair of legs, a chemosensory pit with thin- and thick-walled sensilla for detecting host cues such as odors, , and ; lateral eyes and additional chemoreceptors on the palps and legs further enhance across all stages.

Life history

Developmental stages

Amblyomma americanum undergoes a strictly three-host life cycle, progressing through four distinct developmental stages: , , , and , with each motile stage (, , ) requiring a from a different host to advance. The total life cycle typically spans 1-2 years in natural conditions, influenced by and environmental factors, with development accelerating in warmer southern regions compared to northern areas where cooler may extend the duration. In the egg stage, engorged adult females deposit clusters of 3,000–8,000 eggs in protected ground litter, often in spring, summer, or fall. Incubation requires 1-2 months under optimal temperatures of 25-30°C, though periods can range from 31 to over 60 days depending on ambient conditions; or quiescence may occur in eggs under adverse environmental stress, delaying hatching. Hatching yields six-legged larvae, known as seed ticks, which quest from low vegetation for hosts, primarily small mammals. Larvae feed for 3-5 days until engorged, then drop off to molt into nymphs over 9-27 days in a protected microenvironment. The nymph stage features eight legs and aggressive questing behavior from vegetation; feed for 4-6 days on medium-sized hosts before dropping to molt into adults, a process that may involve overwintering if conditions are unfavorable. Adults, also eight-legged, quest actively; males may feed minimally or not at all, while females feed for 8-12 days on large hosts, during which mating occurs on the host, after which engorged females detach and seek oviposition sites to initiate the next generation.

Reproduction and behavior

Mating in Amblyomma americanum occurs on the host after both males and s have partially fed, with s releasing sex pheromones from their genital operculum to attract males. These pheromones, including 2,6-dichlorophenol, are detected by males via chemoreceptors in Haller's organ on the forelegs, prompting males to locate and mount feeding s. Males may with multiple s, transferring spermatophores externally before resuming feeding, while a single suffices for . Following full engorgement, mated females detach from the host and seek protected ground sites, such as leaf litter or soil crevices, for oviposition, where they deposit 3,000–8,000 eggs in a single mass over 2–3 weeks. Females select sites with high relative (>85%) to optimize egg survival, using hygroreceptors in Haller's organ to assess microclimatic conditions during site choice. Post-oviposition, the female dies, exhibiting semelparous typical of ixodid ticks. Questing, the primary host-seeking behavior, involves A. americanum climbing vegetation tips and extending forelegs in an posture, waving them to detect hosts via carbon dioxide, heat, and odors sensed by Haller's organ. Questing height varies by life stage, with larvae and nymphs typically positioning at 0–50 cm above ground to target small mammals, while adults quest higher (50–100 cm or more) for larger hosts like deer. Activity is predominantly diurnal during spring and early summer, peaking midday under moderate temperatures (20–30°C), though questing decreases during extreme heat, shifting ticks to shaded refugia. Larvae and nymphs exhibit aggregation facilitated by assembly pheromones, such as those from and in , which promote clustering in humid microsites to enhance and molting synchronization. Unfed adults demonstrate extended longevity, surviving up to 25 months under conditions at 23–25°C and 95% relative , enabling overwintering and opportunistic feeding. In contrast, engorged females survive 1–2 months post-drop-off, focused solely on oviposition before death.

Distribution and ecology

Geographic range

Amblyomma americanum, commonly known as the lone star tick, is native to the eastern, southern, and , with its range spanning from westward to the Atlantic coast and northward from the to southern and . This distribution encompasses much of the Northeast, , and Midwest regions, where the tick is the most abundant human-biting in many areas. Historically, A. americanum was widespread across the in the mid-18th century, as documented in early naturalist reports, but its range contracted due to widespread and in the . By the late 1800s and early 1900s, it was firmly established in the southeastern states along the Atlantic and Gulf coasts, with limited presence further north. Since the 1990s, the tick has undergone significant northward expansion into the and Northeast, facilitated by milder winter temperatures associated with and the proliferation of as key hosts. This shift has resulted in established populations in previously marginal areas, with recent surveillance as of 2024 documenting expansion into and southern , and 2025 studies reporting ongoing colonization in southern and increasing appearances in . As of 2025, assessments highlight risks of establishment in new areas like , alongside continued spread into the Midwest and Northeast. Introduced populations of A. americanum outside the are rare and primarily confined to adjacent regions; records in northwestern exist, but many historical reports from and likely represent misidentifications with morphologically similar species within the cajennense species complex. The tick's northward and elevational limits are constrained by cold intolerance, with immature stages particularly vulnerable to prolonged exposure below -10°C, and by higher altitudes exceeding approximately 1,500 m, where suitable conditions diminish. Prevalence is notably highest in forested uplands such as the Ozark Mountains of and the , where habitat suitability supports dense populations; recent analyses indicate substantial increases in modeled suitable habitat in northern latitudes compared to the 1990s baseline, driven by .

Habitat preferences

Amblyomma americanum is a habitat generalist, commonly found in woodlands, grasslands, and urban edges, where it thrives in microhabitats such as leaf litter and tall grasses. This favors environments with dense vegetation and edge habitats between wooded areas and open fields, which provide suitable conditions for questing behavior. The species exhibits specific preferences, requiring high relative humidity levels exceeding 80% and moderate temperatures between 15°C and 30°C to maintain activity and survival. It avoids direct , instead utilizing shaded areas to minimize risk while questing on . Regarding and , A. americanum prefers loamy soils in oak-hickory forests, which support the leaf litter essential for protection and moisture retention. Seasonally, questing activity peaks in spring and summer, with nymphs and adults most active from to , while ticks overwinter in leaf litter to endure colder months. Recent research in south-central from 2025 has linked fine-scale distribution of A. americanum to factors such as canopy cover, , and the presence of leaf litter, highlighting positive associations with forested habitats. This study also notes urban , with ticks persisting in suburban yards amid increasing development. Ongoing range expansion has enabled A. americanum to colonize new habitats, including northern forests.

Host interactions

Amblyomma americanum exhibits a three-host life cycle, in which each developmental stage—larva, , and —feeds on a different host to complete engorgement and development. Larvae and nymphs are generalist feeders, primarily parasitizing small mammals such as mice and meadow voles, ground-frequenting birds, and reptiles including , allowing for broad host utilization during early stages. In contrast, adults show a bias toward larger mammals, with serving as the primary host, though they also feed on other medium to large mammals like and dogs. This stage-specific host specificity facilitates the tick's dispersal, as immature stages on migratory birds can contribute to long-distance transport. Upon locating a suitable host through questing , A. americanum attaches using its barbed hypostome, which is secured by a cement-like substance secreted from the salivary glands, forming a durable cone that anchors the mouthparts into the host's and resists dislodgement. Preferred attachment sites vary by host but commonly include areas with thin and high vascularity, such as the , ears, and region on mammals like deer and dogs. The feeding process is protracted, lasting several days to a week per stage, during which the tick slowly engorges by rupturing host capillaries and imbibing blood; contains anti-hemostatic factors to inhibit clotting and immunosuppressive components to modulate the host's , enabling prolonged attachment without rejection. Females, in particular, acquire a substantial , engorging to weights averaging around 0.63 g, which supports and egg production. Infestations by A. americanum can impose notable burdens on hosts, particularly , where hundreds of ticks may parasitize a single individual, leading to , in severe cases, and potential secondary infections at feeding sites. Hosts mitigate these impacts through grooming behaviors, such as and rubbing, which reduce attachment success and remove attached ticks, thereby limiting the number that complete engorgement. This host defense mechanism underscores the evolutionary pressures shaping the tick's salivary adaptations for evasion.

Medical significance

Transmitted pathogens

Amblyomma americanum, commonly known as the lone star tick, serves as a vector for several bacterial, viral, and other pathogens, primarily acquired during blood meals from infected hosts and transmitted to new hosts through bites. These pathogens are maintained through transstadial transmission, where they persist from larval to nymphal and adult stages within the tick, with minimal evidence of from female ticks to their eggs for most agents. Co-feeding transmission, where uninfected ticks acquire pathogens from infected ones feeding nearby on the same host, also contributes to pathogen spread among populations.

Bacterial Pathogens

The primary bacterial pathogens transmitted by A. americanum include species of Ehrlichia, Francisella, and Rickettsia. Ehrlichia chaffeensis, the causative agent of human monocytic ehrlichiosis, is efficiently acquired by larval and nymphal ticks feeding on infected white-tailed deer or other reservoir hosts and transmitted transstadially to subsequent life stages and hosts. Similarly, Ehrlichia ewingii, responsible for canine granulocytic ehrlichiosis and occasionally human infections, follows a comparable transstadial transmission pathway, with ticks acquiring the bacterium during feeding on infected canids. Francisella tularensis, the etiological agent of tularemia, can be transmitted by A. americanum nymphs and adults, though experimental studies indicate lower vector efficiency compared to other tick species like Dermacentor variabilis. Rickettsia amblyommatis, a member of the spotted fever group rickettsiae, is widely prevalent in A. americanum and capable of transstadial and co-feeding transmission, potentially contributing to mild rickettsial illnesses in humans.

Viral Pathogens

A. americanum transmits emerging bunyaviruses, including Heartland virus (HRTV) and Bourbon virus (BRBV). HRTV, associated with severe febrile illness, is acquired by ticks feeding on infected such as raccoons and transmitted transstadially, with studies demonstrating transstadial and co-feeding transmission, with evidence of transovarial passage in some experiments. BRBV, linked to acute and multi-organ failure, is similarly vectored by A. americanum, with evidence of horizontal and transstadial transmission in field-collected ticks from endemic areas like . These viruses highlight the tick's role in novel pathogen emergence, with detection rates in ticks varying by region but often below 1% in surveillance efforts.

Other Agents

A. americanum carries Borrelia lonestari, a spirochete considered the putative agent of (STARI), though its role remains unconfirmed due to challenges in culturing the bacterium; transmission occurs transstadially following acquisition from reservoir hosts like birds or small mammals. Protozoan pathogens are rarely associated with A. americanum, with occasional detections of Theileria cervi in ticks feeding on cervids, but no established human transmission. Pathogen prevalence in A. americanum varies regionally, particularly in the . Recent 2025 surveillance data indicate E. chaffeensis infection rates of 1-5% in ticks from southeastern states like and , with higher rates (up to 15%) in some localized hotspots; similar patterns hold for E. ewingii at 0-3%, while R. amblyommatis often exceeds 20-30% in the same populations. Viral prevalences remain low, with HRTV and BRBV detected in less than 1% of tested ticks, reflecting focal distribution tied to reservoir abundance. These rates underscore the tick's expanding threat as its range shifts northward.

Associated diseases

Amblyomma americanum, the lone star tick, serves as a vector for several pathogens that cause significant human and animal diseases, primarily in the central and eastern United States. These include bacterial infections like and , as well as emerging viral illnesses such as Heartland and Bourbon viruses. Transmission occurs through tick bites, with symptoms often appearing 1-2 weeks post-exposure, and early treatment is crucial for bacterial cases to prevent severe complications. Human monocytic ehrlichiosis (HME), caused by and transmitted by A. americanum, presents with acute symptoms including high fever, severe , muscle aches (), chills, and fatigue. A occurs in about 20-30% of cases but typically spares the palms and soles. In the , HME accounts for approximately 2,000 confirmed cases annually as of 2019, with overall incidence exceeding 2,000 reports per year in recent years (data as of 2025), concentrated in the South and Midwest. Mortality is less than 1% when treated promptly with antibiotics like , though untreated cases can lead to organ failure. Tularemia, resulting from Francisella tularensis vectored by A. americanum among other means, most commonly manifests as the ulceroglandular form, characterized by a skin ulcer at the bite site and swollen lymph nodes. Inhalation of contaminated aerosols poses an additional transmission risk, potentially causing pneumonic with respiratory symptoms. Nationally, a mean of 205 cases were reported annually from 2011-2022, ranging from 149 to 314, with recent showing cases increasing to 220 in 2024 and further cases in 2025 (as of November 2025); higher burdens occur in states like and . Southern tick-associated rash illness (STARI) is linked to A. americanum bites and features a characteristic expanding red rash resembling the of , often appearing within 7 days of exposure. Accompanying symptoms may include fever, , , and joint pain, but the condition is typically self-limiting without long-term sequelae. Its remains unclear, though evidence suggests involvement of tick saliva components rather than a specific . Emerging viral diseases transmitted by A. americanum include Heartland virus disease, first identified in 2009, which causes fever, profound fatigue, , , and muscle aches, with more than 60 cases reported in the as of 2022, primarily in the Midwest and South, and additional cases identified through 2025. Bourbon virus infection, discovered in 2014, presents similarly with fever, , and elevated liver enzymes, and has been fatal in several of the fewer than 10 confirmed cases, mostly in the central . In animals, A. americanum transmits ewingii and E. chaffeensis, causing canine ehrlichiosis in dogs, which manifests as fever, lethargy, anorexia, and bleeding tendencies; serve as key reservoirs for these pathogens. Epidemiologically, diseases from A. americanum are rising due to the 's expanding range driven by and habitat alterations, with tick-borne illness reports increasing over 20% annually in recent years. In , tick-borne diseases surged tenfold from 1990 to 2017, and a 2025 study mapped hotspots, revealing A. americanum prevalence in southern regions, informing targeted surveillance. Prevention focuses on avoiding habitats, applying 20-30% repellents to skin and to clothing, and performing thorough tick checks and prompt removal after outdoor activities.

Alpha-gal syndrome

Alpha-gal syndrome (AGS) is an IgE-mediated allergic condition primarily induced by bites from the lone star tick, Amblyomma americanum, in which the tick's saliva introduces the carbohydrate galactose-alpha-1,3-galactose (alpha-gal) into the human bloodstream, triggering hypersensitivity to this glycan found in non-primate mammalian meats. The mechanism involves the production of specific IgE antibodies against alpha-gal, leading to a delayed anaphylactic response typically occurring 3-6 hours after ingestion of red meat, distinguishing it from typical immediate food allergies. This delayed onset is attributed to the digestion time required for alpha-gal-containing proteins to release the carbohydrate, allowing IgE cross-linking on mast cells and basophils. Symptoms of AGS manifest as , , gastrointestinal distress (such as , , and ), and in severe cases, following consumption of mammalian meats like , , and lamb, but reactions do not occur with or , which lack alpha-gal. These symptoms can also extend to mammalian-derived products, including , in some cases, and certain medications like or . In the United States, AGS prevalence is estimated at up to 450,000 cases as of 2025, with incidence rising in correlation with the expanding range of A. americanum, particularly in the southeastern, midwestern, and mid-Atlantic regions where seroprevalence exceeds 10% in high-risk areas like and . Diagnosis relies on a clinical history of delayed reactions post-red meat ingestion combined with tick exposure, confirmed by skin prick testing or serum-specific IgE levels to alpha-gal (typically >0.1 kU/L indicating ). Management centers on strict avoidance of alpha-gal-containing foods and products, with patients advised to carry epinephrine auto-injectors for use during reactions. Recent 2025 reviews highlight emerging desensitization approaches, such as oral with gradual exposure under medical supervision, though these remain investigational and are not yet standard. Ongoing research gaps include identifying the precise salivary proteins from A. americanum that facilitate alpha-gal transfer and determining long-term remission rates, as some patients experience symptom resolution after years of avoidance and no further bites.

References

  1. https://tickapp.tamu.edu/home/tick-identification/lone-star-tick/
  2. https://www.cdc.gov/ticks/data-research/facts-stats/lone-star-tick-surveillance.html
  3. https://stacks.cdc.gov/view/cdc/25414
  4. https://www.cdc.gov/heartland-virus/causes-and-spread/index.html
  5. https://www.cdc.gov/mmwr/volumes/72/wr/mm7230a2.htm
  6. https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=6943
  7. https://edis.ifas.ufl.edu/publication/IN1017
  8. https://www.sciencedirect.com/science/article/pii/S1877959X23000079
  9. https://pubmed.ncbi.nlm.nih.gov/20380295/
  10. https://pmc.ncbi.nlm.nih.gov/articles/PMC7780746/
  11. https://pmc.ncbi.nlm.nih.gov/articles/PMC6885135/
  12. https://www.cdc.gov/dpdx/ticks/index.html
  13. https://pmc.ncbi.nlm.nih.gov/articles/PMC9235321/
  14. https://www.scielo.br/j/rimtsp/a/WPJXzX5CzrJJb6pFQp6dTwy/
  15. https://www.lsuagcenter.com/articles/page1666644685323
  16. https://link.springer.com/article/10.1007/BF00355031
  17. https://pmc.ncbi.nlm.nih.gov/articles/PMC8352541/
  18. https://onlinelibrary.wiley.com/doi/10.1111/j.1948-7134.2013.12011.x
  19. https://www.pa.gov/agencies/dep/programs-and-services/integration/vector-management/ticks/lone-star-tick
  20. https://www.researchgate.net/publication/281421536_Diapause_and_quiescence_as_two_main_kinds_of_dormancy_and_their_significance_in_life_cycles_of_mites_and_ticks_Chelicerata_Arachnida_Acari_Part_2_Parasitiformes
  21. https://entomology.mgcafe.uky.edu/ef618
  22. https://wwwnc.cdc.gov/eid/article/25/8/18-1293_article
  23. https://pmc.ncbi.nlm.nih.gov/articles/PMC5536051/
  24. https://pubmed.ncbi.nlm.nih.gov/5449398/
  25. https://academic.oup.com/aesa/article-abstract/62/3/628/24159
  26. https://mdc.mo.gov/discover-nature/field-guide/ticks
  27. https://pmc.ncbi.nlm.nih.gov/articles/PMC7677832/
  28. https://bioone.org/journals/systematic-and-applied-acarology/volume-26/issue-12/saa.26.12.9/Questing-behavior-of-adult-iAmblyomma-americanum-iL-in-a/10.11158/saa.26.12.9.short
  29. https://bioone.org/journals/journal-of-medical-entomology/volume-40/issue-4/0022-2585-40.4.395/Meteorologically-Mediated-Diurnal-Questing-of-iIxodes-scapularis-i-and-iAmblyomma/10.1603/0022-2585-40.4.395.short
  30. https://digitalcommons.odu.edu/context/biology_fac_pubs/article/1093/viewcontent/SonenshineTickPheromonesTickControl_OCR_OPT.pdf
  31. https://pmc.ncbi.nlm.nih.gov/articles/PMC10496434/
  32. https://academic.oup.com/jme/article/44/5/732/972497
  33. https://pmc.ncbi.nlm.nih.gov/articles/PMC4596614/
  34. https://pubmed.ncbi.nlm.nih.gov/36482230/
  35. https://ehp.niehs.nih.gov/doi/10.1289/EHP5668
  36. https://knowledgeconnection.mainehealth.org/cgi/viewcontent.cgi?article=1225&context=jmmc
  37. https://academic.oup.com/jme/advance-article-abstract/doi/10.1093/jme/tjaf154/8294046
  38. https://www.igb.illinois.edu/article/study-identifies-hotspots-disease-carrying-ticks-illinois
  39. https://pubmed.ncbi.nlm.nih.gov/41223718/
  40. https://ysph.yale.edu/news-article/lone-star-ticks-nitrogen-dioxide-pollution-and-dementia-care-study-highlight-october-2025-research-roundup/
  41. https://www.sciencedirect.com/science/article/pii/S1877959X1830298X
  42. https://bmcecolevol.biomedcentral.com/articles/10.1186/1471-2148-13-267
  43. https://pubmed.ncbi.nlm.nih.gov/8699473/
  44. https://link.springer.com/article/10.1007/s10493-019-00460-7
  45. https://profiles.wustl.edu/en/publications/landscape-physiognomy-influences-abundance-of-the-lone-star-tick-
  46. https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-025-06661-x
  47. https://www.theguardian.com/us-news/2025/jun/29/lone-star-ticks-increase-climate-crisis
  48. https://www.cell.com/trends/parasitology/fulltext/S1471-4922%2822%2900258-6
  49. https://ticksafety.com/tick-identification/lone-star-tick/
  50. https://academic.oup.com/jme/article/60/5/978/7207981
  51. https://www.mdpi.com/2075-4450/15/9/709
  52. https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecs2.4369
  53. https://medical-entomology.inhs.illinois.edu/files/2023/06/20230612_INHS-MEL_Tick-Cards.pdf
  54. https://forestgeo.si.edu/landscape-physiognomy-influences-abundance-lone-star-tick-amblyomma-americanum-ixodida-ixodidae
  55. https://pmc.ncbi.nlm.nih.gov/articles/PMC10654644/
  56. https://bioone.org/journals/journal-of-parasitology/volume-86/issue-5/0022-3395%282000%29086%255B1156%253AHAASAO%255D2.0.CO%253B2/Host-Associations-and-Seasonal-Activity-of-Amblyomma-americanum-Acari/10.1645/0022-3395%282000%29086%5B1156:HAASAO%5D2.0.CO%3B2.short
  57. https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-025-06999-2
  58. https://pmc.ncbi.nlm.nih.gov/articles/PMC12481979/
  59. https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-024-06142-7
  60. https://extension.missouri.edu/publications/ipm1032
  61. https://www.sciencedirect.com/science/article/pii/S1877959X23000432
  62. https://pmc.ncbi.nlm.nih.gov/articles/PMC5947171/
  63. https://www.merckvetmanual.com/integumentary-system/ticks/ixodid-ticks
  64. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0131292
  65. https://pmc.ncbi.nlm.nih.gov/articles/PMC10784775/
  66. https://www.annualreviews.org/doi/pdf/10.1146/annurev.en.41.010196.000245
  67. https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2025.1520665/full
  68. https://pubmed.ncbi.nlm.nih.gov/14765684/
  69. https://wwwnc.cdc.gov/eid/article/24/11/18-0451_article
  70. https://pubmed.ncbi.nlm.nih.gov/40300591/
  71. https://www.nature.com/articles/s41598-023-40397-x
  72. https://pmc.ncbi.nlm.nih.gov/articles/PMC9729426/
  73. https://pmc.ncbi.nlm.nih.gov/articles/PMC8805489/
  74. https://www.cdc.gov/lyme/about/about-southern-tick-associated-rash-illness.html
  75. https://www.liebertpub.com/doi/full/10.1089/vbz.2023.0009
  76. https://pmc.ncbi.nlm.nih.gov/articles/PMC8086404/
  77. https://www.cdc.gov/tularemia/causes/index.html
  78. https://www.ncbi.nlm.nih.gov/books/NBK441966/
  79. https://rarediseases.org/rare-diseases/human-monocytic-ehrlichiosis-hme/
  80. https://extension.entm.purdue.edu/publichealth/diseases/tick/monocytic.html
  81. https://emedicine.medscape.com/article/235839-overview
  82. https://www.news-medical.net/health/Epidemiology-of-Ehrlichiosis.aspx
  83. https://health.maryland.gov/phpa/pages/tularemia.aspx
  84. https://aldf.com/tularemia/
  85. https://www.cdc.gov/mmwr/volumes/73/wr/mm735152a1.htm
  86. https://www.sciencedirect.com/science/article/pii/S2667114X23000043
  87. https://www.floridahealth.gov/diseases-and-conditions/southern-tick-rash-illness/index.html
  88. https://extension.entm.purdue.edu/publichealth/diseases/tick/stari.html
  89. https://aldf.com/southern-tick-associated-rash-illness-stari/
  90. https://www.cdc.gov/heartland-virus/hcp/clinical-diagnosis/index.html
  91. https://my.clevelandclinic.org/health/diseases/25084-heartland-virus-disease
  92. https://journals.lww.com/pidj/fulltext/2023/05000/comprehensive_review_of_emergence_and_virology_of.18.aspx
  93. https://sebsnjaesnews.rutgers.edu/2023/07/lone-star-ticks-acari-ixodidae-infected-with-bourbon-virus-in-new-jersey/
  94. https://www.cdc.gov/ehrlichiosis/pdfs/fs-ehrlichiosisvet-508.pdf
  95. https://www.sciencedirect.com/science/article/abs/pii/S0304401710002852
  96. https://outdoor.wildlifeillinois.org/articles/ticks-in-illinois-the-rising-risk-of-ehrlichiosis
  97. https://www.researchgate.net/publication/394342822_Spatial_distribution_and_clustering_of_medically_important_tick_species_in_Illinois_Implications_for_tick-borne_disease_risk
  98. https://pmc.ncbi.nlm.nih.gov/articles/PMC10859966/
  99. https://health.ri.gov/tick-borne-diseases
  100. https://portal.ct.gov/-/media/caes/documents/publications/fact_sheets/entomology/repellentfactsheetnewformat2015pdf.pdf
  101. https://pmc.ncbi.nlm.nih.gov/articles/PMC8331069/
  102. https://pmc.ncbi.nlm.nih.gov/articles/PMC9484563/
  103. https://pmc.ncbi.nlm.nih.gov/articles/PMC8974695/
  104. https://www.cdc.gov/alpha-gal-syndrome/about/index.html
  105. https://pmc.ncbi.nlm.nih.gov/articles/PMC7737235/
  106. https://pmc.ncbi.nlm.nih.gov/articles/PMC8344025/
  107. https://pmc.ncbi.nlm.nih.gov/articles/PMC6980324/
  108. https://www.ccjm.org/content/92/5/311
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