Cattle disease carried by ‘self-cloning’ ticks has been identified in another Kentucky county

A disease carried by an invasive tick species has been found in a cow in Barren County, and state officials continue to alert farmers about this new threat to the state’s cattle industry.

This is the second confirmed case of Theileria orientalis Ikedia, an illness spread by the Asian Longhorned tick, in Kentucky cattle, the Kentucky Department of Agriculture said in a news release Tuesday.

The 12-year-old Barren County beef cow had jaundice and rapid breathing as a result of Theileria, a protozoan that “infects red and white blood cells causing severe anemia in cattle as well as abortions, stillbirths, weakness, reluctance to walk, and death,” according to the agriculture department. The cow in Barren County did not die.

But there isn’t a vaccine or “approved effective treatment” for cattle who contract Theileria, and those that are infected can become carriers that spread the disease to other cattle in the herd. The state said this makes “prevention and biosecurity imperative.”

The illness is not a threat to human health, and meat from infected cattle is safe to eat if it has been cooked to the proper temperature, the state said.

Sales of cattle and calves total more than $1 billion a year in Kentucky, according to the 2017 agricultural census, making the cattle industry the third-largest agricultural cash producer in the state, behind grain and poultry products. Barren County, where the most recent case of Theileria was identified, ranked sixth in the state for cattle sales in 2017 and first for milk production.

“Protecting the health of our livestock is a top priority of the Kentucky Department of Agriculture and the Office of the State Veterinarian,” Agriculture Commissioner Ryan Quarles said in the release. “We are working closely with agriculture producers to protect our herds across the state, and contain these cases.”

In August, a beef breed bull in Fleming County died as a result of Theileria infection. The Agriculture Department said then that another beef bull in Hart County had died as a result of the illness, but on Tuesday, the department said further testing determined that bull did not have Theileria.

“As Theileria orientalis Ikeda is a newly detected pathogen in the United States, research into advancing diagnostic testing for this pathogen is ongoing,” Dr. Katie Flynn, the Kentucky state veterinarian, said in the release.

The state veterinarian is conducting free blood testing for Theileria, and the state said affected farms and owners will be kept confidential.

“Results are available to producers. Information gathered will be used to create maps that depict the spread of the ALT (Asian longhorned tick) and Theileria across Kentucky,” the news release stated.

To submit tick samples for identification or cattle blood samples for testing, farmers should contact the Office of the State Veterinarian at statevet@ky.gov or call 502-573-0282.

Farmers are encouraged to take measures to keep ticks off their livestock, such as keeping pastures mowed, keeping cows out of wooded areas and checking cattle for ticks regularly. Acaricides, or chemicals that kill ticks and mites, can be applied with ear tags, or poured or rubbed onto the backs of livestock.

The state said long-acting treatments such as ivermectin, moxidectin and eprinomectin “have shown to be effective in tick control in field research trials.” Producers should also use a clean needle for every injection to help keep blood-borne illnesses from spreading and get a veterinarian involved if an animal is weak or lethargic, the agriculture department said.

Aside from livestock, the Asian Longhorned tick also can attach itself to wildlife, birds, cats, dogs and humans, sometimes in large numbers. The ticks, which are known for their ability to “clone” themselves, were first found in the United States in New Jersey in 2017, and they were found to have spread into Kentucky in 2020.

“This tick is an aggressive biter and frequently builds intense infestations on domestic hosts that can cause stress, reduced growth and severe blood loss,” Jonathan Larson, UK extension entomologist, said in a 2020 news release. “One reason for their rapid buildup is that the female ticks can lay eggs without mating.

“It only takes a single fed female tick to create a population of ticks. Potentially, thousands can be found on an animal.”

Herald-Leader reporter Bill Estep contributed to this report.