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More Asian Longhorn Tick detections in Illinois

A cow/calf specialist with the University of Illinois Extension says the Asian longhorn tick has been confirmed in three more Illinois counties.  

Dr. Teresa Steckler tells Brownfield the invasive species has been discovered in Jefferson, Marion, and Wayne Counties.

“This tick will congregate on animals.”  She says, “There’ll be hundreds of thousands of ticks on animals. It’s parthenogenic, so it does not need a male to reproduce. So, you can start out with one tick, and within a few years, you could have thousands of ticks.”

She says the ticks can become so numerous that cases of livestock death have been reported in other states.

“Guys are going to have to pay much more attention to their livestock.”  She says, “Infestations of these particular ticks can lead to unfortunate death, as we’ve seen already in certain states, whether that’s due to an allergic reaction to the bite or just too much blood loss.”

Steckler says Asian longhorn ticks prefer wet, swampy areas.  She says producers should keep herds clear of those areas and consult their veterinarian to develop an up-to-date parasite management plan.

“The ticks can just really make these animals uncomfortable.”  She says, “And for the Asian longhorn tick, it can carry the disease-causing agent for theileria and cause theileriosis. So, in some instances, some cattle may not survive the infection, but there’s no treatment.”

Asian longhorn ticks were confirmed in Illinois in Hamilton and Morgan Counties in 2024 and Clay and Pope Counties in 2025. Producers can submit suspect tick samples to their local Extension office for proper identification.

Brownfield spoke with Steckler at the 2026 Heart of America Grazing Conference in Effingham, Illinois.

AUDIO: Dr. Teresa Steckler – U of I Extension