Asian Longhorned Tick Guide for Cattle Producers

They Exploded Overnight: East Tennessee Producer Battles Asian Longhorned Tick Outbreak

Tue, 23 Jun 2026 18:29:19 GMT

When East Tennessee cattleman Travis Mundy walked through his pasture on a Saturday in early June, nothing looked out of place. He checked cattle up close, filled mineral and sprayed for flies the way he always does. By Monday, everything had changed. Within 48 hours, a healthy show heifer was dead and her pen mates were crawling with Asian longhorned ticks (ALHTs).

“We drove through them and that’s how we found her, just covered in ticks,” he recalls. “On Saturday, I had actually laid hands on her and never saw a tick or anything.”

Despite aggressive fly and parasite control, an outbreak of ALHTs killed two of Mundy’s high‑value embryo heifers and left neighboring producers with even greater losses. The fast‑spreading tick has turned routine parasite control into a high‑stakes battle.

“They explode overnight,” Mundy summarizes.

From tick free to covered in ticks and dead in 48 hours.

(Travis Mundy)

A “Perfect Storm” for Asian Longhorned Ticks

Mundy manages about 300 cows, mostly Angus, Simmental and SimAngus, spread across multiple farms in East Tennessee, about 30 miles north of Knoxville near Speedwell, Tenn.

“We’re spread out over about 10 or 11 miles, so these farms aren’t close,” he explains, emphasizing they are having tick problems in multiple locations.

This spring, the weather set up exactly the kind of conditions ticks love.

“We’ve had a drought, so we kind of let our pastures grow a little bit. We usually have them clipped before now, but we didn’t get any rain at all in May, so we kind of let them grow,” he explains. “We got 3 inches of rain Sunday and Monday; that was a perfect storm for the ticks — the wet weather, the high grass and the high humidity.”

Mundy delivered seven vials of ticks to the the University of Tennessee. There it was confirmed all ticks were the Asian Longhorned Ticks.

(Travis Mundy)

When he and his veterinarian started pulling samples and sending them to the University of Tennessee, the results were clear: They were ALHTs.

The Hidden Threat: 300 Ticks in a Single Ear

On May 5, Mundy lost a 5-month-old calf.

“We thought at first with the weather changes and heat it was pneumonia,” he explains.

But after he and his son started clipping some of the longer haired ones in that pasture, they found a lot of ticks. “They were covered in them under thick hair and there were 200 to 300 ticks in each ear,” he says. “We were in these cattle every day, like a feet away, and you might see one or two ticks, but you couldn’t see under all that hair.”

Around that same time, they started hearing of neighbors losing cattle with confirmed necropsy of Theileria. ALHTs carry Theileria orientalis, a protozoan parasite that infects red and white blood cells, causing anemia and, in severe cases, death. Bovine theileriosis is the disease caused by Theileria orientalis.

The outbreak hit some of Mundy’s most valuable genetics.

“All three of them were show heifers, and two of them were full sib embryo babies worth a lot of money,” he says.

What surprised him most was which animals went down first. “Those show heifers were probably the best-doing, fattest, best in shape,” he says. “You would think those ticks would get on the worst, poorest animal in there and kill her first, but that’s not what happened.”

His neighbors have fared worse. “A neighbor lost seven; another guy just in the edge of Virginia he lost 20-some,” Mundy adds, noting state necropsies there came back positive for Theileria.

The tick pressure isn’t isolated to a single pasture.

“It is in several pastures —four miles, two miles, 10 miles, they’re not even close, and every one of them — a couple worse than others, but they were all pretty bad,” he summarizes.

The infestation is so heavy that simply moving gates or clipping pastures can bring ticks onto people and pets. “You can walk to the gate to open the gate and you’ll have five or six crawling up your pant leg,” Mundy says. “I brought my dog with me, and I found like three on him. You just can’t keep them off either. It’s terrible.”

Control Efforts: What Helped and What Didn’t

Mundy was not ignoring parasite control before the outbreak. His program included:

Regular permethrin sprays
Pour-on and injectable dewormers
IGR mineral and garlic-based mineral products

“We spray permethrin at least two or three times a week for flies,” he says. “These heifers had been poured about the 10th of May. We poured them again that night, and the next morning a lot of the ticks were dead, and we gave them injectable dewormer also.”

He also feeds an IGR mineral for flies. “They say the garlic will help with ticks,” he says. “We feed free-choice mineral every year, and it didn’t stop them.”

He has moved quickly to add new tools:

Tick vaccine : “We ordered the tick vaccine,” he says. “All of our animals have had the first dose, and about half of them have had the second. Hopefully that tick vaccine will work and keep them from getting Theileria, and it helps kill the ticks too.”
New pour-on product ( Exzolt ): “Apparently in South America it’s working on ticks, so we’re gonna try it,” Mundy adds.

Still, Mundy says producers shouldn’t expect any single product to be a silver bullet, especially given AHLTs are asexual and they can have 2,000 eggs at a time without ever encountering a male. That reproductive shortcut is a major reason populations can explode in a single season once the tick establishes in an area.

Management Lessons: Pasture Height and Fly Tags

Looking back, Mundy says pasture management and fly tags will be key parts of his long-term strategy.

“They say the best thing you can do is keep your pastures clipped, because they thrive in that high grass,” he says, adding that neighbors with thinner, more closely grazed grass “don’t have any ticks.”

He’s also going back to an older tool many had abandoned — fly tags.

“A lot of people in this country quit using fly tags several years ago,” he explains. “We kind of got away from it. But I can tell you, we’ll fly tag from now on, for sure. I can’t help but think that if we would have had a fly tag in these cattle, their ears wouldn’t have been caked full of ticks.”

His producer-to-producer advice for preparation is straightforward: Clip grass, vaccinate, worm early and fly tags.

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Be Aware: Dangerous Asian Longhorned Tick Continues Migrating West

Wed, 18 Jun 2025 14:42:46 GMT

The Asian Longhorned Tick (ALHT) poses a serious threat to cattle health. ALHTs carry Theileria, which is a protozoan parasite that infects red and white blood cells. It can lead to anemia and, in some cases, death.

ALHTs are native to eastern Asia, eastern China, Japan, the Russian Far East and Korea but were introduced to Australia, New Zealand and western Pacific Islands. In other countries, it can also be called a bush tick, cattle tick or scrub tick.

In the U.S., ALHT was first detected in New Jersey in 2017. Since then, it has spread to more than 20 states with recent confirmations in Illinois , Michigan and Iowa .

According to USDA’s Animal and Plant Health Inspection Service (APHIS) ALHTs are known to carry pathogens, which can cause disease and may also cause distress to the host from their feeding in large numbers. For example, a dairy cow may have a 25% decrease in milk production after becoming a host.

A female can reproduce without a mate and lay up to 2,000 eggs at a time. This can cause great stress on a heavily infested animal and result in reduced growth and production. A severe infestation can kill the animal from excessive blood loss.

Asian longhorned tick life stages and relative actual size.

(Photos of unfed ticks by Centers for Disease Control. Photos of engorged ticks by Jim Occi, Rutgers, Center for Vector Biology.)

What does it look like?

Unfed ALHTs range from a light reddish-tan to a dark red with brown, dark markings. While the adult female grows to the size of a pea when full of blood, other stages of the tick are very small — about the size of a sesame seed.

Adult females are a grey-green with yellowish markings. Male ticks are rare.

APHIS reports it only takes a single tick to create a population in a new location.

The above photos are of a AHLT engorged (on the left) and an adult AHLT not engorged.

(New Jersey Department of Agriculture)

ALHTs need warm-blooded hosts to feed and survive. They have been found on various species of domestic animals — such as sheep, goats, dogs, cats, horses, cattle and chickens — and wildlife. The tick has also been found on people.

What are the health risks?

APHIS says ALHTs are not known to carry Lyme disease, but they can cause tickborne diseases affecting humans and animals such as:

Rocky Mountain spotted fever
Heartland virus
Powassan virus

APHIS says those diseases have not been confirmed outside of a laboratory setting in the U.S. In addition, U.S. ALHT populations can transmit U.S. Theileria orientalis Ikeda strain (Cattle theileriosis) in the laboratory.

In an Iowa State University release , Grant Dewell, Extension beef veterinarian and associate professor, says cattle affected by Theileriosis will show signs of lethargy, anemia and difficulty breathing. They may develop ventral edema, exercise intolerance, jaundice and abortions.

“Although signs of Theileriosis are similar to anaplasmosis, younger animals and calves often display more severe signs compared to mature cows and bulls,” he says. “Due to anemia from both tick infestation and Theileria, the risk of death can be elevated. If cattle producers suspect either Theileria or ALHT, have a veterinarian collect appropriate samples and submit them to a veterinary diagnostic lab.”

According to an Oklahoma State University press release , under laboratory conditions ALHT is a competent vector of numerous pathogens that can cause disease in humans, including Rickettsia rickettsii (Rocky Mountain Spotted Fever), Heartland Virus and Powassan Virus.

In “ Clinical Infectious Diseases, ” Bobbi Pritt, MD, MSC, with the division of clinical microbiology at the Mayo Clinic in Rochester, Minn., reported a human bite that occurred in New York in 2019. She says though the report of a human bite isn’t surprising, it proves the invasive longhorned tick continues to bite hosts in its newest location.

“This is extremely worrisome for several reasons,” she writes. “One reason is Asian longhorned ticks can carry several important human pathogens, including the potentially fatal severe fever with thrombocytopenia syndrome (SFTS) virus and Rickettsia japonica, which cases Japanese spotted fever. While these pathogens have yet to be found in the United States, there is a risk of their future introduction.”

Also, Pritt says several other human pathogens have been detected in the ticks, but it’s not clear if the ALHT species are able to transmit them to humans. They include Anaplasma, Ehrlichia, Rickettsia, and Borrelia species. Lyme disease is caused by Borrelia burgdorferi bacteria.

She warns the organisms are present in states where ALHTs have been found and that it’s possible the tick — known to be an aggressive biter— might be able to transmit Heartland virus given its close relationship to SFTS virus.

How to Tackle Ticks

According to APHIS, various strategies effectively mitigate tick populations on hosts and in the environment.

Regular tick treatments should be effective against ALHTs. Consult your veterinarian or agriculture extension agent about which products to use.
Check your livestock for ticks regularly.
Safely remove ticks from people and pets as quickly as possible. If you think you’ve found an ALHT, seal it in a zip-top bag and give it to your veterinarian for identification.
Habitat modifications can help prevent ticks on feedlots and pastures. This may include mowing grass, removing trees, reducing shade by thinning trees, understory removal and placing mulch barriers.
Apply acaricide using label instructions to tick habitats, such as woodland edges and grassy patches, during times when ticks are most actively seeking hosts. Although it varies by year, ALHTs are generally active from March to November. Consult your state and local regulations for approved acaricides.

“Cattle producers should aggressively control external parasites this summer,” Dewell summarizes. “Insecticide ear tags alone are not enough to control ticks. Consider incorporating a back rubber or regularly applying a pour-on during the summer. Pyrethroid-based products are also available that include a tick control label. If an increase in tick infestations is observed, an avermectin pour-on may be the best intervention.”

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