The Gulf Coast tick, Amblyomma maculatum, is an emerging tick of both medical and veterinary concern in Ohio, as it can transmit Rickettsia parkeri (which causes spotted fever rickettsiosis in humans) and Hepatozoon americanum (which causes American canine hepatozoonosis in dogs). Gulf Coast tick infestations can also result in Gotch ear in livestock, which is characterized by swelling and drooping of the ear and can even result in necrosis. These ticks were first detected in Ohio in 1990. Since then, established populations have been found in at least three separate counties. This fact sheet contains information about the Gulf Coast tick, including its identification, geographical distribution, life cycle, and the pathogens it transmits. It also contains guidance on how to best prevent tick bites and what to do in the case of a tick bite. This information is pertinent to all Ohioans who spend time outdoors, and/or own companion animals and livestock.
Identification
Gulf Coast ticks are small- to medium-sized ticks, with adults having ornate markings on their reddish-brown bodies. Adult Gulf Coast ticks are about 3–7 millimeters long and 2– 4 millimeters wide (Hooker, et al., 1912). A plate called the scutum covers the entire back of adult males, featuring ornate, whitish markings (Fig. 1). The scutum of a female Gulf Coast tick only covers half of its back and is similarly ornately decorated with whitish lines (Fig. 1). After taking a blood meal, both males and females are larger and may appear grey. All adult ticks have eight legs. Nymphal Gulf Coast ticks are also eight-legged but are much smaller—around the size of a poppy seed (1.33 millimeters long x 0.75 millimeters wide when unfed) (Hooker, et al., 1912). Larval Gulf Coast ticks are six-legged and smaller than 1 millimeter wide (Hooker, et al., 1912). Notably, adult Gulf Coast ticks can be easily mistaken for the American dog tick (Dermacentor variabilis) due to their similar appearance (Fig. 2). Both ticks have dark, reddish-brown bodies and ornate markings on their scutum (The University of Rhode Island, 2025). However, Gulf Coast ticks have long and slender mouthparts, whereas the mouthparts on American dog ticks are shorter and stouter.
Distribution and Spread
Gulf Coast ticks have only recently been detected in Ohio. Since around the year 2000, this tick has expanded dramatically across the Eastern United States (The University of Rhode Island, 2025; Centers for Disease Control and Prevention, 2025a; Sabet, et al., 2023). They are commonly found in the Southeast and Great Plains regions, with small and isolated populations across the Mid-Atlantic, Midwest, and Northeast United States (The University of Rhode Island, 2025; Centers for Disease Control and Prevention, 2025; Sabet, et al., 2023). In Ohio, established populations of Gulf Coast ticks are in three counties (Butler, Hamilton, and Franklin) and they have been reported in at least 17 other Ohio counties (Fig. 3).
Life Cycle, Activity, and Preferred Habitat
Gulf Coast ticks have a 2-year life cycle (Fig. 4) with four life stages:
- Egg
- Larva
- Nymph
- Adult
Their seasonality, abundance, and activity vary greatly by life stage and location (Teel, et al., 2010). In Ohio, the seasonal distribution and abundance of the different life stages of the Gulf Coast tick is not well understood. However, adults are commonly found in the warm summer months while immature life stages (larva and nymph) occur in fall and spring.
Gulf Coast ticks, like all ticks, feed exclusively on the blood of vertebrates (e.g., birds and mammals). They seek out and feed on a different host during each life stage. Adults are generalist feeders and can be found on a variety of larger mammals, whereas larval and nymphal ticks are typically found on birds and smaller mammals (Teel, et al., 2010). Gulf Coast ticks are commonly found in grassland prairies dominated by grasses and shrubs, with little to no tree cover. They can also be found in recently disturbed habitats with shrubs and long grasses (early successional habitats) (Teel, et al., 2010).
Effects on Humans and Animals, Including Pathogen Transmission
When Gulf Coast ticks bite livestock, the bite can cause extensive damage, like inflammation, edema, abscess, predisposition to anemia, and secondary infection (Teel, et al., 2010). Infestations have been known to result in a condition called Gotch ear, seen most often in ruminants (Edwards, 2011). This is a condition of the ear, resulting in lesions at the site of the tick bite, as well as crusting, balding, reddening of the skin, and drooping or curling of the ear. In extreme cases, it can even lead to total loss of the ear (Edwards, 2011). Gotch ear is commonly associated with the Gulf Coast tick, but no known pathogen is associated with this condition—it is the result of mechanical damage associated with tick feeding (Edwards, 2011).
Gulf Coast ticks are the primary vector of the human pathogen Rickettsia parkeri, which causes a type of spotted fever rickettsiosis (cdc.gov/other-spotted-fever/about) (Centers for Disease Control and Prevention, 2024; Centers for Disease Control and Prevention, 2025b). This bacterial pathogen is transmitted through a tick bite and can result in an eschar (ulcerated, necrotic lesion) at the site of the tick bite. Symptoms of infection include fever, rash, muscle aches, and headaches several days after the appearance of the eschar.
Gulf Coast ticks are also the primary vector of the canine pathogen Hepatozoon americanum, which causes American canine hepatozoonosis (Ewing & Panciera, 2003). This protozoan pathogen is primarily transmitted to dogs when the dog consumes an infected tick when grooming itself. Infection with this pathogen can result in severe lethargy and death in dogs.
How can I protect myself?
- Prevent tick bites (Note 1).
- Remove biting ticks immediately (Note 2).
- Record the date of the bite and save the tick in rubbing alcohol, hand sanitizer, a sealed bag, or in the freezer.
- If symptoms develop, seek medical attention.
- Consider submitting your tick for identification to your local health department or sending a photo to TickSpotters (web.uri.edu/tickencounter/tickspotters/submit).
How Can I Protect My Companion Animals/Livestock from Gulf Coast Ticks?
Many effective tick prevention products are available to protect companion animals. Work with your veterinarian to find the best tick-protection product that fits your budget and your pet’s tolerance and lifestyle. Check companion animals for ticks after spending time outdoors. When treating livestock, use a product specifically labeled for tick control and follow all withdrawal times before the animals or their products enter the food supply to ensure they are not contaminated with pesticide residues. For all animal applications, make sure to read, understand, and follow the label guidance. The label is the law.
The College of Food, Agricultural, and Environmental Sciences at The Ohio State University has created a Knowledge Exchange landing site titled Welcome to the Bite Site (kx.osu.edu/bite) with information on ticks, mosquitoes, and other blood-feeding arthropods.
Links
About other spotted fever rickettsioses
(cdc.gov/other-spotted-fever/about)
Find the repellent that is right for you
(epa.gov/insect-repellents/find-repellent-right-you)
How to do a tick check: Tips for you and your pet
(web.uri.edu/tickencounter/ticksmart/tick-prevention-and-protection-videos/how-to-do-a-tick-check-2)
Ohio Department of Health: Estimated distribution of Gulf Coast ticks in Ohio map
(odh.ohio.gov/know-our-programs/zoonotic-disease-program/media/gulf-coast-tick-distribution-map)
Permethrin general fact sheet
(npic.orst.edu/factsheets/PermGen.html)
TickSpotters
(web.uri.edu/tickencounter/tickspotters)
Welcome to the Bite Site: Your guide to ticks, mosquitoes, and other biting pests
(kx.osu.edu/bite)
References
Centers for Disease Control and Prevention. (n.d.). Public health image library (PHIL).
phil.cdc.gov
Centers for Disease Control and Prevention. (2025a). Where ticks live.
cdc.gov/ticks/about/where-ticks-live.html
Centers for Disease Control and Prevention (2025b). Tickborne diseases of the United States.
cdc.gov/ticks/hcp/data-research/tickborne-disease-reference-guide
Centers for Disease Control and Prevention. (2024). About other spotted fever rickettsioses.
cdc.gov/other-spotted-fever/about/index.html
Edwards, K. T. (2011). Gotch ear: a poorly described, local, pathologic condition of livestock associated primarily with the Gulf Coast tick, Amblyomma maculatum. Veterinary Parasitology, 183(1–2), 1–7.
DOI: 10.1016/j.vetpar.2011.09.038
Ewing, S. A., & Panciera, R. J. (2003). American canine hepatozoonosis. Anim Health Res Rev., 4(1), 27–34.
DOI: 10.1079/ahrr200348
Hooker, W. A., Bishopp, F. C., Wood, H. P., & Hunter, W. D. (1912). The life history and bionomics of some North American ticks. U. S. Department of Agriculture, Bureau of Entomology.
Sabet, A., Ward, S. F., & Pesapane, R. (2023). Amblyomma maculatum (Gulf Coast tick). Trends in Parasitology, 39(11), 971–972.
doi.org/10.1016/j.pt.2023.08.005
Teel, P. D., Ketchum, H. R., Mock, D. E., Wright, R. E., & Strey, O. F. (2010). The Gulf Coast tick: a review of the life history, ecology, distribution, and emergence as an arthropod of medical and veterinary importance. Journal of Medical Entomology, 47(5): 707–722.
DOI: 10.1603/me10029
The University of Rhode Island. (2025). Gulf Coast tick.
web.uri.edu/tickencounter/species/gulf-coast-tick