Theileria in Asian Longhorned Ticks: Threat to Cattle in Ohio

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Ohio’s Country Journal writer, Tim McDermott (Ohio State University Extension Educator) 03.31.24 published, “Asian longhorned ticks and Theileria in 2024.” McDermott warns of the increase of medically important tick species in Ohio and the growing risk to humans, companion animals, and livestock from transmission of pathogens. Just 20 years ago, Ohio was home to only one species of medically important tick, and by 2024 that number has grown to 5. 

The invasive Asian longhorned tick, first discovered in Ohio in 2020, transmits Theileria orientalis (a protozoa that infects red and white blood cells) to cattle with the first case documented in 2022. Tick infestation has also resulted in mortality of cattle from high numbers of ticks feeding upon individuals. The longhorned tick is documented in Franklin, Delaware, Ross, Gallia, Vinton, Jackson, Athens, Morgan, Monroe, Belmont, and Guernsey counties with positive cases of Theileria diagnosed in cattle in 8 counties (Crawford, Guernsey, Adams, Columbiana, Tuscarawas, Monroe, Belmont, and Harrison). 

Theileria causes increased heart rates and respiratory rates, anemia, jaundice, open females, and increased mortality. Though there is a test to diagnose Theileria in a suspected case, there is no approved treatment for this disease in the US.

For More Information:

Read Ohio’s Country Journal Article 

Read more LDA Articles on Asian Longhorned Tick