The Asian Longhorned Tick Is Found on Dogs More Than Cattle

USDA records 179 detections on dogs against 73 on cattle. One female can found a population without mating, which is why a single treatment does not hold.

USDA surveillance has recorded the Asian longhorned tick on dogs more often than on cattle, 179 detections against 73, even though federal agencies file the species under cattle diseases. A single female can produce a population without ever mating, laying up to 2,000 eggs, which is why one missed tick can repopulate a treated property. No transmission of a human pathogen by this tick has been documented in the United States.

This tick arrived quietly, spread through suburban states, and is still being written about as a livestock problem. For anyone with a yard and a dog in the eastern United States, the more useful framing is what makes it different from the ticks already there, and why a single treatment does not hold.

It was here seven years before anyone noticed

Officials reported the first US detection outside a port inspection in November 2017, on a sheep in Hunterdon County, New Jersey. Retrospective examination of archived specimens then pushed the first known US collection back to August 2010, from a white-tailed deer in Tyler County, West Virginia.

Where it is now, and why the counts disagree

Three different numbers circulate, and each is defensible on its own terms.

The USDA report is the best sourced of the three. Its distribution is notable for being suburban rather than agricultural: New Jersey has it in all 21 counties and Delaware in all 3, with Virginia at 51 counties, West Virginia 35, North Carolina 34 and Pennsylvania 31.

USDA also separates established populations, meaning at least six ticks or two of three life stages in a single collection period, from single reported specimens. Those are different things, and most coverage treats them identically.

One tick can start an infestation

This is the biological fact that changes the control problem. Females reproduce parthenogenetically, meaning without a male, so a single fed female can found an entire population and lay up to 2,000 eggs.

What that looks like in practice was documented on an Ohio farm in 2021, where a five-year-old bull died of blood loss. Researchers collected almost 10,000 ticks in about 90 minutes and estimated more than a million across a pasture of roughly 25 acres.

What it means for people, and what it does not

Here the evidence needs to be stated carefully, because the topic attracts overstatement in both directions.

• No documented US transmission of a human pathogen by this tick. The CDC’s position is that it is not yet known if or how often these ticks pass pathogens to people.
• It is not a competent vector of Lyme disease. USDA states the ticks are not competent vectors of the bacteria causing Lyme, nor of Anaplasma phagocytophilum.
• Laboratory competence is not field transmission. The bacteria causing Rocky Mountain spotted fever have not been found in these ticks in nature.
• It does bite people. USDA surveillance records 131 human-positive submissions. It also appears less attracted to humans than native species; research found blacklegged ticks crawl toward a human host while these crawl away.
• The confirmed harm is to livestock. Theileria orientalis Ikeda, which causes anaemia and death in cattle, was detected in a Virginia herd in 2017, and US ticks transmitted it to cattle in laboratory conditions.

Both of the following are true and should be said together: this tick bites people, and no human disease transmission from it has been documented in this country.

Does normal tick treatment work on it

Yes, and that is not the same as saying a single treatment solves it. USDA states that regular tick treatments should be effective against the species. The complication is reproduction. As an Ohio State researcher put it, you cannot spray your way out of an Asian longhorned tick infestation; it requires an integrated approach, even though most available control agents do kill them. On the Ohio farm, ticks returned despite pesticide applications.

The practical conclusion is about intervals and coverage rather than chemistry. One surviving fed female re-founds the population without needing a mate, so treatment that leaves a refuge, or that is not repeated, gives the population a path back. Habitat work matters as much as product: keeping grass short, clearing brush at the yard edge, and reducing the wildlife hosts that carry ticks in. White-tailed deer are the single most common wild host in USDA’s data, at 175 detections.

For pricing and what a treatment programme involves, see tick control costs. Worth reading alongside that is the evidence on what yard tick spraying actually achieves, which found large reductions in tick numbers without a matching reduction in human illness, though with a measurable benefit for pets. For the general approach, see integrated pest management, and for the wildlife side, wildlife removal.

Telling it apart

It is small, reddish-brown and plain. Adults are around 2.5 mm, often smaller than a sesame seed, and pea-sized when engorged. The identifying feature is the absence of features: no white dot as on a female lone star tick, no ornate white pattern as on an American dog tick. A tiny, unmarked, uniformly reddish-brown tick found in a cluster on an animal is the signature, and the clustering matters, because parthenogenesis means large numbers can build on one host.

Frequently asked questions

Are Asian longhorned ticks dangerous to humans?

No human pathogen transmission by this tick has been documented in the United States. The CDC states it is not yet known whether or how often these ticks can pass pathogens to people, and notes the species appears less attracted to humans than native ticks. It does bite people, with 131 human-positive submissions in USDA surveillance.

Do Asian longhorned ticks carry Lyme disease?

USDA states they are not competent vectors of Borrelia burgdorferi, the bacterium that causes Lyme disease, nor of Anaplasma phagocytophilum. Being found in an area where Lyme occurs does not make this species a carrier of it.

What states have Asian longhorned ticks?

USDA’s most recent published national situation report confirms 21 states plus Washington DC across 285 counties, as of April 2025. CDC’s public map still shows 20 states as of April 2024, and Alabama cited 24 eastern states when confirming its first detection in April 2026. New Jersey and Delaware have it in every county.

Can one tick really start an infestation?

Yes. Females reproduce without mating and can lay up to 2,000 eggs, so a single fed female can found a population. On one Ohio farm researchers collected nearly 10,000 ticks in about 90 minutes and estimated more than a million across about 25 acres.

Does regular tick spray work on Asian longhorned ticks?

The chemistry works; the single-treatment model does not. USDA states regular tick treatments should be effective, while researchers who worked the Ohio infestation reported that you cannot spray your way out of it and that ticks returned despite applications. Because one surviving female can restart the population, retreatment intervals and complete coverage matter more than product choice.

Do Asian longhorned ticks bite dogs?

Frequently. Dogs are the most common domestic animal host in USDA surveillance, with 179 detections against 73 on cattle. Cats account for 33. Recent state first-detections in Alabama and Kansas were both on dogs.

What does an Asian longhorned tick look like?

Small, plain and reddish-brown, around 2.5 mm as an adult and often smaller than a sesame seed. It has none of the markings used to identify common US ticks: no white dot, no ornate pattern. Finding several unmarked small ticks clustered on one animal is the practical signal.

Sources

• USDA APHIS, National Haemaphysalis longicornis Situation Report, April 2025. tickapp.tamu.edu
• USDA APHIS, Asian Longhorned Tick. Last modified May 2026. aphis.usda.gov
• U.S. Centers for Disease Control and Prevention, Where Ticks Live, July 2025. cdc.gov
• Alabama Department of Agriculture and Industries, Asian Longhorned Tick Detected in Alabama, April 2026. agi.alabama.gov
• Ohio State University, An exotic tick that can kill cattle is spreading across Ohio, on research published in the Journal of Medical Entomology 60(5), 2023. news.osu.edu
• Theileria orientalis Ikeda Genotype in Cattle, Virginia, USA. Emerging Infectious Diseases 25(9), September 2019. cdc.gov
• Cornell University Integrated Pest Management, Asian Longhorned Tick. cals.cornell.edu