USDA Grant Helps Arkansas Researchers Track Invasive Tick

MADDIE JOHNSON

FAYETTEVILLE, ARKANSAS

Researchers with the University of Arkansas System Division of Agriculture have landed a $270,000 grant to map the spread of an invasive tick species in Arkansas.

The Asian longhorned tick, Haemaphysalis longicornis, was first identified in Arkansas in 2018, a year after it was confirmed in the United States. Scientists are unsure how the tick first entered the U.S., but the risk posed to producers is clear, says Emily McDermott, assistant professor of entomology with the Arkansas Agricultural Experiment Station.

The tick, often the size of a sesame seed, can pose devastating risks for cattle. With the ability to reproduce without a male, a single tick can lay up to 2,000 eggs, and hundreds of ticks can infest a single animal, leading to its death.

McDermott said it’s important to define exactly where this tick lives, as it’s been confirmed in the state but has likely not spread across Arkansas. She is hopeful that the U.S. Department of Agriculture’s financial support will aid in the team’s ability to do just that.

The team will enlist citizens throughout the state for help with this mapping. Researchers will start by surveying a 1.5-kilometer radius in Benton, Independence and Washington counties, three of the Arkansas counties where the tick has been identified. Within these boundaries, they will sample at least 20 percent of a herd of cattle. If no longhorned tick is found, researchers will expand their surveillance to an 8-kilometer radius, repeating their methods until they identify the presence of the tick or reach the state line. If a surveillance site does test positive for tick presence, secondary surveillance will begin expanding in rings from the area, drawing a more definite boundary for where the tick is distributed throughout the state.

All ticks collected from cattle, and those collected from the trapping that researchers will also conduct at each site, will then be tested for Theileria orientalis Ikeda genotype, a deadly parasite transmitted by the longhorned tick that was discovered for the first time in Arkansas just weeks ago, to assess the current risk of this threat.

Along with McDermott, the research team includes Jeremy Powell, veterinarian and animal science professor, and Kelly Loftin, extension entomologist and professor of medical and veterinary entomology, who serves as the principal investigator for the grant. The experiment station is the research arm of the University of Arkansas System Division of Agriculture, and the extension is the division’s outreach arm.

Division support for pilot data

The team first received a $15,000 internal animal health grant from the division before procuring the $270,000 USDA grant, which runs from July 2024 to June 2026.

The internal grant allowed preliminary data collection that confirmed a presence of the longhorned tick at the division’s Savoy and Batesville research locations in northwest and north-central Arkansas. Testing at the research station near Hope in the southwestern part of the state was negative.

Loftin said the presence of the tick in Batesville has increased considerably, illustrating its growing threat to the state’s cattle populations.

With these findings, the team went after further funding to address the fundamental question of their current work: how widespread is this tick?

Loftin said the research was inspired in part by mysterious sicknesses in animals that mirrored the symptoms associated with anaplasmosis, a tick-borne disease commonly found in Arkansas. Testing for anaplasmosis, however, came up negative.

Deadly parasite

Once the longhorned tick attacks an animal, it can transmit Theileria orientalis Ikeda, which can kill up to one in 20 infected cattle, according to the USDA.

The presence of the longhorned tick in the United States caused researchers to question whether it could be carrying and spreading this disease throughout Arkansas.

Loftin said their research on the tick heightens producers’ caution of ectoparasites, or parasites that live on the exterior of a host.“It seems like it’s getting to a point where ectoparasites are just as important as the internal parasites,” Loftin said.

Intervention for prevention

The team’s research proves to be timely, with Theileria orientalis Ikeda being identified in Boone County, its first case and death in the state, within the last two months, as reported by the Arkansas Cattlemen’s Association.

Powell said that while there is no drug approved by the Food and Drug Administration to treat Theileria, the team hopes to use its findings to enhance producers’ prevention efforts.

McDermott also said it’s easier to intervene and reduce tick presence when their population size is small, as they can reach high population sizes very quickly.

Powell added that this knowledge could help producers deter ticks through more effective methods of pasture mowing and parasiticide use.

“If we’re able to get a better handle on the prevalence and incidence of the tick, and then also test those ticks for Theileria, we would have a better idea to pass information along to the producers,” Powell said.  ∆

MADDIE JOHNSON: University of Arkansas