Asian Longhorned Tick Poses Pet Concerns

Spring has sprung, and with warming weather, the bugs come out ready to make a meal of our pets. If you plan to spend any time outside, it’s not too early to think about ticks, those creepy crawly spider cousins that bug pets and spread disease. I’ve written about tick-borne diseases before. Here in Texas, we have pets (and people!) diagnosed with Lyme disease, Rocky Mountain Spotted Fever, and/or ehrlichiosis. Yes, some folks end up with a combination of illnesses. There are other diseases ticks carry, and I recently learned about a new invasive tick species. The Asian longhorned tick (Haemaphysalis longicornis) poses additional risks.

How did the Asian longhorned tick get to America? Officially reported first in 2017, it appeared outside a quarantine facility on a sheep farm in New Jersey. It hasn’t yet reached Texas, but may soon. It looks similar to other tick species and has the ability to transmit many bacterial, viral, and protozoal pathogens that can make humans and animals sick.

Kathryn Duncan, DVM, PhD, DACVM, parasitology field specialist with Merck Animal Health, graciously agreed to answer my questions about this new risk to our pets. She says this tick most likely entered our country through imported or shipped animals. (This is NOT a sponsored post and I am not being compensated for sharing this important information.)

Three life stages of the Asian longhorned tick. Photo: Matt Bertone, NC State Extension

What to Know About the Asian Longhorned Tick

Dr. Duncan says this tick feeds on the blood of dogs, cats, livestock, and people, just like other ticks. “It’s not picky when choosing a host,” she says.

Asian longhorned ticks can develop significant infestations because the female does not require a male to reproduce. Males are rare. Females reproduce in a process called parthenogenesis, and lay up to 2,500 eggs at once, during late spring to early summer. Eggs hatch in late summer to early fall.

“A large population of this tick can develop quickly,” she says. In fact, the CDC reports that a single animal may host up to a thousand ticks at one time.

This tick has three life stages: 6-legged larva, 8-legged nymph, and the adult. It must eat during each life stage to mature to the next. Following the meal, it falls off of its host, molts, and searches for a new host. The tick “quests” for a victim by lurking on grass tips or leaves, legs reaching out to snag a host. Longhorned tick larvae may quest in groups of 50-100 on a single grass blade.

Each tick bite damages the skin as they feed. So just imagine hundreds or a thousand of these tiny vampires on a single animal, and the pain and distress they cause your pet. “They create wounds that may become secondarily infected, and transmit pathogens,” says Dr. Duncan.

Close-up Haemaphysalis longicornis on leaves.

Where in the US is the Asian Longhorned Tick?

After its introduction in New Jersey, it has spread down the eastern coast and as far west as Arkansas and Missouri. Currently, it appears in 18 states in America. “We expect it to establish in many other states in the future,” says Dr. Duncan.

She says the environmental factors, such as temperature and humidity, directly affect a tick’s ability to thrive. Availability of hosts also determines where you find ticks, as they are always in search of their next meal.

“With the changes in our environment, tick researchers have already shown the changes in tick distribution. We see some ticks that were restricted to the southeastern US now as far north as Maine. And when the Asian longhorned tick was introduced in the US, researchers took information about this tick’s preferred habitat and modeled that to our climate in the US. They showed this tick is likely able to establish in almost all of the US.”

She concludes that ALL pet owners should pay attention to tick concerns, since you find them in every region of the US. “Certain areas can be notoriously famous for their tick populations, such as northeastern, upper midwestern, southeastern, and south central US.”

TIcks like dog ears.

Diseases Asian Longhorn Ticks Transmit

We’re fortunate that the United States has not yet confirmed any disease transmission to people, dogs, or cats from this tick. However, Dr. Duncan notes that theileriosis due to Theileria orientalis Ikeda (transmitted by this tick) has been diagnosed in cattle in the US.

In other countries, “This tick transmits many disease agents, such as Anaplasma, Ehrlichia, Borrelia, Rickettsia, Babesia, SFTSV (severe fever with thrombocytopenia syndrome virus), and more. In experimental studies, this tick can transmit the agent of Rocky Mountain Spotted fever.” Some good news from these experimental studies also showed Asian longhorn ticks don’t effectively transmit the causative agent of Lyme disease (Borrelia burgdorferi).

“Even though ticks have been in our environment for many, many years, the threat of ticks is growing. The introduction of another tick species is a perfect example of this,” says Dr. Duncan.

Many ticks can parasitize a single dog, and cause great discomfort and potential for disease.

How to Protect Pets and People from Asian Longhorned Ticks

Use the same protections as for other kinds of ticks and parasites. For instance, avoid tick environments such as woods and tall grass, and keep lawns mowed short. Dr. Duncan admits that offers challenges with this tick, though. “We all enjoy being outside and the Asian longhorned tick has been found in backyards, which is somewhat unique for a tick.”

Removing ticks promptly reduces the opportunity for disease transmission. But finding them all proves difficult, particularly with thickly furred pets, especially with a species that can number in the hundreds on a single host. Veterinary-recommended year-round tick control products offer the best prevention and protection for our pets. There are many tick preventive products available, so ask your veterinarian for a recommendation.

Where Do You Live?

If you live in an endemic region known to host the Asian longhorned tick, ask your veterinarian about Bravecto® Chews for dogs and Bravecto® topical for cats or Bravecto Plus® for cats (from Merck Animal Health). These currently are the only products with FDA-approval for the control of the Asian longhorned tick.

“Many efficacy and safety studies are required before FDA will grant approval, so pet owners and veterinarians can feel assured when they use these products,” says Dr. Duncan. Pet owners have their own human-specific tick repellent products. NOTE: Human tick repellent products are NOT safe to use on pets)

Dr. Duncan says researchers continue to collect these ticks from the environment and hosts to test them for pathogens, to improve knowledge of any disease risks from the Asian longhorn tick. “As research continues, we will hopefully have more to share so everyone can be prepared.”

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Amy Shojai, CABC is a certified cat & dog behavior consultant, a consultant to the pet industry, and the award-winning author of 35+ pet-centric books and Thrillers with Bite! Oh, and she loves bling!