(NEXSTAR) — An invasive tick that can prove fatal for cattle has spread to a new state, officials have confirmed.
The Asian longhorned tick, which was first detected in the U.S. in 2017, was found in Maine earlier this summer, University of Maine and state conservation officials said this week. This marks the furthest north the invasive species has been found.
As of September 2025, the tick has been able to spread to nearly two dozen states.
Here’s what to know.
What is the Asian longhorned tick?
While invasive, the Asian longhorned tick looks relatively similar to any native tick you may be familiar with.
Before the tick has fed, it will have a light reddish-tan or dark reddish appearance, the U.S. Department of Agriculture explains. At this stage, they may be smaller than a sesame seed. After feeding, the tick — primarily females, as males are rare — can grow to the size of a pea, appearing gray-green with yellow markings.
Female Asian longhorned ticks are able to lay eggs without mating, making it “a successful invader of new geographic regions.”
Where has the Asian longhorned tick been found?
Since first being detected in the U.S. in 2017, the Asian longhorned tick has made its way into nearly two dozen states.
According to the U.S. Department of Agriculture, as of April 2025, the tick has been reported in Arkansas, Delaware, Connecticut, Georgia, Illinois, Indiana, Kentucky, Maryland, Massachusetts, Missouri, New Jersey, New York, North Carolina, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, Tennessee, Virginia, and West Virginia.
And, like in Maine, the tick has recently spread to Michigan, USDA officials confirmed earlier this year.
Is the Asian longhorned tick dangerous?
Research has found that the ticks may carry pathogens, including the bacteria that cause Rocky Mountain spotted fever (RMSF). Spread through bites by infected ticks, RMSF commonly causes fever, headaches, nausea, vomiting, stomach or muscle pain, a lack of appetite, and a rash, the Centers for Disease Control and Prevention explain.
Asian longhorned ticks in the U.S., however, have not been found to carry this bacterium.
For livestock, the Asian longhorned tick can be a serious threat.
“These ticks can be so high on a single cow that they can actually result in so much blood loss that the animal can die from that,” Dr. Jonathan Cammack, Assistant Professor at OSU and State Extension Specialist for Livestock, Entomology, and Parasitology, previously told Nexstar’s KFOR. Their ability to reproduce — a female can lay up to 2,500 eggs on a single animal — can worsen the situation.
Regular tick treatments are considered to be effective against the Asian longhorned tick, according to the USDA. If you suspect your livestock or pet may have been exposed to the invasive tick, you should contact your veterinarian.
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