Asian Longhorned Ticks Discovered in Berrien County

This is the first detection of Asian longhorned ticks in Michigan

LANSING, Mich. — Today, the Michigan Department of Agriculture and Rural Development (MDARD) is reporting the first detection of the Asian longhorned tick (ALHT) in the state. Two ALHT nymphs were found through routine tick surveillance efforts, which were being conducted at Grand Mere State Park in Berrien County by Calvin University. The specimens were sent to the U.S. Department of Agriculture's National Veterinary Services Laboratories and confirmed as ALHT on June 11, 2025. While the tick poses a potential disease risk to all mammals and birds, the impact to livestock (specifically cattle) is a major concern. Owners are urged to work with their veterinarian to treat their animals for ticks, perform regular tick checks, and keep pastures and lawns mowed and clear of brush to help keep their animals safe and healthy.

"This discovery highlights the value of the contributions from our academic partners and the necessity of our continued collaboration to protect animal health throughout Michigan," said State Veterinarian Dr. Nora Wineland, DVM, MS, DACVPM. "By knowing this species of tick is in our state, we will increase our educational outreach to producers, animal owners, and animal health professionals so we can all do our part to safeguard animal and public health."

"Calvin research students have been studying the ecology and distribution of ticks in West Michigan since 2020. The students worked with our close partners at Michigan State University and collaborating state agencies to initially identify these ticks as nymphal longhorned ticks," said William Miller, Ph.D., CWB (Certified Wildlife Biologist), and Assistant Professor of Biology at Calvin University. "Since the longhorned tick is an agricultural pest of concern, our research team is continuing surveillance in the region to identify the potential distribution of the species, which will help to define the risk it poses to livestock."

How did the ALHT get here?

While native to east Asia, the ALHT (Haemaphysalis longicornis) was first detected in New Jersey in 2017. Since then, it has spread to 21 other states in the eastern United States including Indiana and Ohio. The ticks can be transported through the movement of animals, people, equipment, etc.

MDARD will continue to take a One Health approach to respond to this detection and work with academic partners, local health departments, and other state and federal agencies to conduct additional surveillance around the state.

What does it look like?

ALHTs are light brown in color and can easily be mistaken for other tick species. 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 or even smaller.

What are the health risks?

ALHTs 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.

Even though this tick is not known to carry Lyme disease, they are capable of causing tickborne diseases affecting humans and animals, such as: Rocky Mountain spotted fever, heartland virus, and Powassan virus. However, those diseases have not been confirmed outside of a laboratory setting in the United States. ALHTs collected in other parts of the country have been found to carry Theileria orientalis, one of the pathogens that cause bovine theileriosis which is a reportable animal disease.

Since female ALHTs can reproduce without mating and lay up to 2,000 eggs at a time, the ticks have been known to form large infestations on one animal, causing stress and reducing its growth and production. A severe infestation can even kill an animal due to blood loss.

What can I do?

For domestic animals, taking preventative measures and being vigilant are the best ways to protect against ALHTs and any other species of tick. Some of these strategies include:

• Having regular tick treatments. Contact your veterinarian for more information about tick prevention for your animals.
• Performing a tick check. Look around their eyes, ears, limbs, tail, and toes for any ticks. If a tick is found, safely remove it as quickly as possible.
• Practicing tick prevention on pastures and lawns. Keep tall grass trimmed back along buildings and property edges, mow lawns, remove brush and leaf litter, and create mulch barriers to help make spaces tick safe.
• Sending in ticks for identification. If you find an unusual-looking tick and/or think you have found on ALHT, please send it in to the Michigan Department of Health and Human Services. Instructions can be found on Michigan's Emerging Diseases website.

Overall, if you have any questions regarding the health of your animals, please consult your veterinarian.

Where can I learn more?

To learn more about the ALHT, where they have been found in the United States, and general preventative strategies, please visit the U.S. Department of Agriculture's website or MDARD's website.

For more on ticks and tickborne diseases in Michigan as well as instructions for submitting ticks for identification, visit the Emerging Diseases website.

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