Adams County Residents Warned About Invasive Asian Longhorned Tick This Spring

A public health advisory published March 26 put Adams County residents on notice about the Asian longhorned tick (Haemaphysalis longicornis), an invasive species that has been establishing itself across Ohio since 2021 and is now active enough to warrant a spring warning for homeowners, outdoor workers, hikers, and pet owners throughout the county.

The tick is reddish in color and, when unfed, can be about the size of a sesame seed or even smaller, making it easy to overlook after a walk through tall grass or a day working in the field. It is also easily confused with other ticks more familiar to Adams County residents, such as the American dog tick, which adds another layer of difficulty to early detection.

What makes this species particularly alarming for a county built on agriculture is its reproductive capacity. Female Asian longhorned ticks can reproduce without mating and lay up to 2,000 eggs, which allows them to quickly establish large populations. In 2021, the presence of these ticks reached a critical point on a southeastern Ohio farm, where tens of thousands of ticks were blamed for the deaths of three cattle. Livestock may become heavily infested, leading to decreased production, aborted or stillbirths, and death; the ticks may also transmit bovine theileriosis, causing potentially fatal anemia in cattle.

For Adams County farmers with cattle, sheep, or horses, that threat is not abstract. The species has been reported on more than two dozen host species, including sheep, goats, horses, cattle, chickens, dogs, cats, and humans. Although it varies by year, Asian longhorned ticks are generally active from March to November, meaning the window of risk opens now and runs through fall harvest.

The advisory outlines several practical steps for avoiding contact and catching ticks early. Wearing long sleeves and tucking pant legs into socks when moving through brushy areas or tall grass forms a basic physical barrier. Using tick repellents and wearing long sleeves and pants can help reduce the risk of encountering these ticks. After any time outdoors, check pets and family members carefully, paying attention to the scalp, behind the ears, and under the arms. If a tick is found, use fine-tipped tweezers, grasp as close to the skin as possible, and pull with steady, even pressure. Twisting or jerking the tick can cause the mouthparts to break off and remain in the skin.

Reporting unusual tick finds matters beyond individual households. Ohio State University researchers are asking residents to assist by sending any ticks they find to the university; instructions are available by emailing ticks@osu.edu. This kind of resident reporting has already proven critical: Ohio State researchers first received a call about the 2021 Monroe County cattle deaths from a local farmer. Entomologists use submitted specimens to track how far the species has spread across the state.

Ohio State tick researcher Dr. Risa Pesapane has been direct about the long-term picture: "They are going to spread to pretty much every part of Ohio and they are going to be a long-term management problem. There is no getting rid of them." For a county where pasture land, creek bottoms, and public trails bring people and animals into regular contact with tick habitat, that prognosis makes spring preparation all the more urgent.