The Michigan Department of Agriculture and Rural Development (MDARD) announced today the first-ever detection of the Asian longhorned tick (ALHT) in Michigan. Two ALHT nymphs were identified through routine surveillance at Grand Mere State Park in Berrien County, marking a significant new concern for animal health in the state.
The discovery was made by Calvin University researchers conducting tick surveillance and subsequently confirmed on June 11, 2025, by the U.S. Department of Agriculture’s National Veterinary Services Laboratories.
While the Asian longhorned tick poses a potential disease risk to all mammals and birds, the primary concern for Michigan officials is its impact on livestock, particularly cattle. Owners are strongly advised to collaborate with their veterinarians on tick treatment plans, conduct regular tick checks on their animals, and maintain pastures and lawns by keeping them mowed and clear of brush to mitigate risk.
“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,” stated State Veterinarian Dr. Nora Wineland. “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.”
William Miller, Ph.D., Assistant Professor of Biology at Calvin University, explained the role of their research. “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 and collaborating state agencies to initially identify these ticks as nymphal longhorned ticks.” He added, “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 It Arrived
Native to East Asia, the Asian longhorned tick ( Haemaphysalis longicornis) was first identified in the United States in New Jersey in 2017. Since then, it has spread to 21 other states in the eastern U.S., including neighboring Indiana and Ohio. The ticks can spread through the movement of animals, people, and equipment.
MDARD stated they are committed to a “One Health” approach in response to this detection, working collaboratively with academic partners, local health departments, and other state and federal agencies to conduct further surveillance across Michigan.
Identification and Potential Risks
Asian longhorned ticks are light brown and can be easily confused with other tick species. While adult females can swell to the size of a pea when engorged with blood, other life stages are much smaller, comparable to a sesame seed or even smaller.
These ticks have been found on a wide range of domestic animals, including sheep, goats, dogs, cats, horses, cattle, and chickens, as well as wildlife. They have also been found on humans.
Although not known to carry Lyme disease, ALHTs are capable of transmitting various tickborne diseases that affect both humans and animals, such as Rocky Mountain spotted fever, heartland virus, and Powassan virus.
A significant concern with the Asian longhorned tick is its ability to reproduce asexually, with female ALHTs laying up to 2,000 eggs at a time without mating. This can lead to massive infestations on a single animal, causing stress, reducing growth and production, and in severe cases, even death due to blood loss.
What You Can Do
For domestic animals, preventative measures and vigilance are crucial in protecting against ALHTs and other tick species. Recommended strategies include:
Regular tick treatments: Consult your veterinarian for guidance on appropriate tick prevention for your animals.
Performing tick checks: Thoroughly inspect animals 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, especially along buildings and property edges. Mow lawns, remove brush and leaf litter, and consider creating mulch barriers to help create tick-safe spaces.
Sending in ticks for identification: If you encounter an unusual-looking tick or suspect you have found an ALHT, send it to the Michigan Department of Health and Human Services. Instructions are available on Michigan’s Emerging Diseases website.
For any questions regarding the health of your animals, always consult your veterinarian.
For more information on the Asian longhorned tick, its distribution in the United States, and general preventative strategies, visit the U.S. Department of Agriculture’s website or MDARD’s website.
Photo courtesy MDARD.
