Asian Longhorned Tick
Haemaphysalis longicornis · also called Longhorned tick, Bush tick, Cattle tick and Scrub tick · Last checked November 3, 2026.
The Asian longhorned tick is an invasive tick from eastern Asia, first detected in the US in 2017 and now found in many eastern states. It is small (unfed stages about the size of a sesame seed or smaller) and light reddish-tan to dark reddish. Females can lay eggs without mating, so thousands of ticks may be found at once on animals or in grass. USDA calls it a serious threat to livestock. CDC says it appears less attracted to humans than native ticks and that it is not yet known whether, or how often, it passes germs to people in the US. Official sources do not describe it as venomous. APHIS
On this page
Is the Asian longhorned tick dangerous?
CDC: in other countries, germs spread by these ticks can make people and animals seriously ill. In the US it is likely some ticks will be found to carry harmful germs, but it is not yet known if and how often they pass them to people. CDC
“With ongoing testing of ticks collected in the United States, it is likely that some ticks will be found to contain pathogens that can be harmful to people. However, we do not yet know if and how often these ticks are able to pass these pathogens along to people and make them ill.”
Bites and stings: Yes. CDC: found on pets, livestock, wildlife and people. Indiana Department of Health: feeds on pets, livestock, wildlife and people, but appears less attracted to humans than native ticks.
No official source we use states whether this animal is venomous. That does not mean it is harmless: do not handle it.
If someone is bitten or stung, call 911 or Poison Help at 1-800-222-1222.
How to identify an Asian longhorned tick
A photo or description can narrow it down, but cannot confirm what an animal is or that it is safe. Look from a distance and do not handle wild animals.
Size: Unfed stages about the size of a sesame seed or smaller; an engorged female is about the size of a pea. APHIS
Colors: Unfed: light reddish-tan to dark reddish, with brown dark markings; fed adult females: grey-green with yellowish markings; alabama: light brown. Pattern: University of Kentucky: brown body with no identifiable markings.
Key features
- Short mouthparts University of Kentucky Entomology Extension
- Can occur by the thousands on one animal or in grass CDC
Young
Larvae, nymphs and adults may be on the same animal; unfed stages are about sesame-seed size or smaller.
Where the Asian longhorned tick lives
- Native or listed
- Nonnative or not established
- No official record in our data
- 1–9
- 10–99
- 100–999
- 1,000+
State boundaries: U.S. Census Bureau, cartographic boundary file cb_2024_us_state_20m.
When it is active
USDA APHIS: generally active March to November, varying by year. University of Kentucky: active March-September in other eastern states; Kentucky seasonality still under study. APHIS
Too few open-licence records to chart by month: GBIF has only 29 records CC0 or CC BY human observations of this species in the US.
Habitat and habits
Habitat: Woodland areas and fields; grass and shrubs; on pets, livestock and wildlife. University of Kentucky Entomology Extension
Behavior: Aggressive feeders that can build up heavy infestations on single animals.
Diet: Blood: feeds on three hosts in its life (larva, nymph, adult), including pets, livestock, wildlife and people.
Young: US populations are parthenogenetic: a female lays up to about 2,000 eggs without mating; males are uncommon. The life cycle can be completed in about six months.
Legal status and reporting
Federal: Not an ESA species: the ECOS query for the genus Haemaphysalis returned no records. ECOS
Invasive status: Invasive pest (USDA APHIS); not normally found in the Western Hemisphere. APHIS
Report: USDA APHIS: if you think you've found one, seal it in a zip-top bag and give it to your veterinarian for identification. Indiana: report unusual ticks or large infestations to the Board of Animal Health (317-544-2400). Alabama: report unusual or heavy infestations to your veterinarian, Extension agent, diagnostic lab and the State Veterinarian's Office (334-240-7255). APHIS
Questions about the Asian longhorned tick
Asian longhorned tick diseases
In its home range it spreads germs that can make people and animals seriously ill (CDC). In the US, USDA says it has transmitted the cattle parasite Theileria orientalis Ikeda in the lab and the parasite has been found in field-collected ticks. Lab studies show it can carry the Rocky Mountain spotted fever bacteria, but these have not been found in wild ticks. USDA says it is not a competent vector of the Lyme disease or human anaplasmosis bacteria.
Asian longhorned tick diseases in humans
CDC says it is not yet known if and how often these ticks pass germs to people in the US. Indiana's health department says there is no evidence they have transmitted pathogens to people in the US, and Tennessee lists no known human diseases in the US. For an emergency, call 911 or Poison Help at 1-800-222-1222.
Asian longhorned tick symptoms in humans
CDC says it is not yet known whether these ticks make people ill in the US. For an emergency, call 911 or Poison Help at 1-800-222-1222.
Asian longhorned tick diseases in dogs
The official sources checked name no specific dog disease from this tick in the US. CDC says it has been found on pets, and Alabama's first detection was on a dog. USDA says to give a suspected tick to your veterinarian for identification.
Asian longhorned tick map
USDA maintains the official map of where longhorned ticks have been found (CDC). CDC's list as of April 12, 2024 names 20 states. Alabama added a detection in April 2026 and says it has been reported in 24 eastern states.
Asian longhorned tick nymph
USDA says the unfed stages other than adult females are very small, about the size of a sesame seed or smaller. Alabama says larvae, nymphs and adults may be found on the same animal.
Asian longhorned tick tennessee
Yes. CDC lists Tennessee among the states where it has been found, and the Tennessee Department of Health says it was recently found in eastern Tennessee and lists no known human diseases in the US.
Sources
- Asian Longhorned Ticks. USDA Animal and Plant Health Inspection Service (APHIS). archived copy, captured October 18, 2026; checked November 3, 2026.
Quoted passages (4)
“Other unfed stages of the tick are very small, about the size of a sesame seed, or even smaller.”
“Although it varies by year, Asian longhorned ticks are generally active from March to November.”
“Asian longhorned ticks (Haemaphysalis longicornis) are invasive pests that pose a serious threat to livestock in the United States.”
“If you think you've found an Asian longhorned tick, seal it in a zip-top bag and give it to your veterinarian for identification.”
- Where Ticks Live. CDC. archived copy, captured September 28, 2026; checked November 3, 2026.
Quoted passages (2)
“With ongoing testing of ticks collected in the United States, it is likely that some ticks will be found to contain pathogens that can be harmful to people. However, we do not yet know if and how often these ticks are able to pass these pathogens along to people and make them ill.”
“Thousands of ticks may be found at a time in grass or shrubs or on an animal.”
- Haemaphysalis longicornis (Asian longhorned tick). Indiana Department of Health. dateModified 2026-10-01; checked November 3, 2026.
Quoted passages (3)
“These ticks attach to and feed on three different animal or human hosts during their lifetimes (once as larvae, once as nymphs, and once as adults).”
“They are aggressive feeders and feed on a variety of host species, including pets, livestock, wildlife, and people”
“ALHT females can reproduce without needing to mate (parthenogenesis) and can lay up to 2,000 eggs at a time.”
- Ticks and Disease in Kentucky (EF618). University of Kentucky Entomology Extension. Revised 3/26; checked November 3, 2026.
Quoted passages (2)
“Mouthparts are short.”
“Habitat: Woodland areas and fields.”
- Asian Longhorned Tick Detected in Alabama. Alabama Department of Agriculture and Industries. April 23, 2026; checked November 3, 2026.
Quoted passages (1)
“Larvae, nymphs, and adults may be present on the same animal.”
- USFWS ECOS species report: Scientific Name like 'Haemaphysalis%' (ESA listing status). U.S. Fish and Wildlife Service (ECOS). database queried November 3, 2026; checked November 3, 2026.
- Vector-Borne Diseases. Tennessee Department of Health. archived copy, captured August 6, 2026; checked November 3, 2026.
- GBIF.org occurrence records, human observations licensed CC0 1.0 or CC BY 4.0 only, accessed November 3, 2026. The datasets behind these counts are listed on our Sources page.
- State boundaries: U.S. Census Bureau, cartographic boundary file cb_2024_us_state_20m.