Invasive Tick Species Spreading In VA, CDC Says: What To Know

VIRGINIA — A winter-hardy species of exotic tick that researchers think killed three otherwise healthy cattle in Ohio, has been found in Virginia and 18 other states. Cattle producers have been warned to watch for the tick, which has been confirmed in 38 Virginia counties.

In addition to Virginia, Asian longhorned ticks have been found in Arkansas, Connecticut, Delaware, Georgia, Indiana, Kentucky, Maryland, Massachusetts, Missouri, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, and West Virginia, according to the Centers for Disease Control and Prevention.

The Virginia Department of Agriculture and Consumer Sciences said the increasing numbers of the longhorn ticks raise a concern for the health of livestock. "ALT is a vector for the parasite Theileria orientalis Ikeda which can cause theileriosis in livestock, including cattle," the agency said.

“When cattle develop theileriosis, signs of anemia, fever, jaundice, difficulty breathing and lethargy can be present,” said Dr. Charles Broaddus, VDACS state veterinarian. “As there is no cure, treatment should focus on supportive measures including stress reduction, nutritional supplementation and above all, prevention in the form of tick control.”

Once symptoms of theileriosis show, testing is an important step to confirm the presence of the parasite. Dr. Kevin Lahmers of the Virginia-Maryland College of Veterinary Medicine, has been leading research on this new pathogen, and Virginia Tech Animal Laboratory Services (ViTALS) at VMCVM has developed a PCR test for Theileria orientalis and Anaplasma marginale.. This is performed on whole blood in EDTA in live animals but can be run on fresh spleen, as well.

Samples can be submitted directly to ViTALS vitals.vetmed.vt.edu or through VDACS lab services. Dr. Lahmers can be reached at klahmers@vt.edu or 540.231.4320.

Because there is no approved treatment in the U.S., controlling Asian longhorned tick populations is the best management option, experts said. Virginia Cooperative Extension has these tips to manage ALT populations:

• Regularly inspect cattle for ticks. As ALT is very small, a thorough inspection is required.
• During inspections, pay close attention to cattle that appear lethargic or anemic, have low weight, or have patchy hair.
• Inspect all newly purchased cattle before adding to a herd.
• Submit tick samples to your local extension agent for species confirmation.
• Consider using pesticide-impregnated ear-tags.
• Use backrubbers and siderubbers charged with appropriate pesticides in high traffic areas.
• For treatment in areas of high tick concentrations, use direct pour-on treatments.
• Treat all animals in a herd for ticks at the same time.
• Consider keeping pastures mowed shorter.
• Consider keeping cattle out of wooded areas.
• Check any pets or working animals that are in contact with herds.

The CDC said Asian longhorn ticks, first reported in the United States in 2017, appear to be less attracted to human skin than well-known native ticks, such as the blacklegged tick, lone star tick, and the American dog tick. The agency warned, however, that the germs spread by tick bites have made people and animals seriously ill in other countries.

Researchers at Ohio State University concluded that a 2021 infestation of Asian longhorned ticks was behind the deaths of three cattle, including a previously healthy adult bull who died of severe blood loss from tick bites, according to a news release.

The bull was 5 years old and “enormous,” Risa Pesapane, the senior author of the paper published in the Journal of Medical Entomology and an assistant professor of preventive medicine at Ohio State, said in a news release.

“To have been taken down by exsanguination by ticks, you can imagine that was tens of thousands of ticks on one animal,” said Pesapane.

The ticks feed mainly on deer and raccoons but have also been found on dogs and cats, cattle sheep, goats, horses, squirrels, rabbits, skunks, opossums and groundhogs.

The tiny brown ticks are about the size of a sesame seed in some stages and pea size when engorged. Females reproduce asexually and can lay up to 2,000 eggs at a time. Their offspring can do the same.

“There are no other ticks in North America that do that. So they can just march on, with exponential growth, without any limitation of having to find a mate,” Pesapane said. “Where the habitat is ideal, and anecdotally it seems that unmowed pastures are an ideal location, there’s little stopping them from generating these huge numbers.”

Researchers estimated there were about 1 million longhorned ticks in the pasture of about 25 acres where the cattle that died had been grazing. A pesticide application in 2021 eradicated the ticks, but they returned a year later.

“The good news about the ticks, though, is that most tick control agents that we currently have seemed to kill them,” Pesapane said. “Still, managing them is not easy because of how numerous they are and how easily they can come back.”

Pesticide applications have limits, though. Asian longhorned ticks hide easily in vegetation, and unless the pesticide is applied directly to the insect, they’re likely to survive.

The best recourse is to target them early in the growing season when adults become active again, but before they lay eggs.

“But for a variety of reasons, I tell people you cannot spray your way out of an Asian longhorned tick infestation — it will require an integrated approach,” Pesapane said.

She added, “There is no getting rid of them.”

If you think you’ve found an Asian longhorned tick, remove it from the animal or person as soon as possible, the CDC advised. Save the ticks in rubbing alcohol in a jar or resealable bag, and contact your local health department for more guidance.