Rosslyn Biggs, DVM, The Asian longhorned tick, Haemaphysalis longicornis, has successfully established itself in countries around the world. It likely entered the United States in 2010 on a human, pet or livestock animal. The tick was first identified on cattle in northeastern Oklahoma in summer 2024.
The Asian longhorned tick parasitizes multiple species, including humans, pets, livestock and wildlife such as birds. Relatively small compared to native ticks, it is a three-host tick that spends 90% of its life off the animal. Larva, commonly called seed ticks, feed on smaller animals. The nymph and adult stages then feed on larger animals including humans and cattle. The four most common animals this tick has been found on within the United States are dogs, white-tailed deer, raccoons and cattle.
The female tick can reproduce without mating and may lay 1,000 to 2,000 eggs at a time. A single female tick has the potential to create an established population in a newly introduced location within two to three weeks.
Severe infestations of the Asian longhorned tick in cattle can lead to death from the stress of excessive blood loss. Production losses, such as decreased milk production and slowed growth are substantial. The Asian longhorned tick has also been recognized as a vector for multiple diseases of both humans and animals, including viral, bacterial and protozoan agents.
In other countries, the tick is the primary vector of Theileria orientalis Ikeda genotype in cattle. The protozoal agent causes clinical signs similar to anaplasmosis-anemia, fever, lethargy, jaundice and death. The mortality rate for cattle infected with T. orientalis Ikeda genotype varies from 3% to 90%. T. orientalis Ikeda genotype has been identified in the United States, but as of this time not in Oklahoma.
Researchers at Oklahoma State University College of Veterinary Medicine are continuing their project to evaluate the status of the pathogenic T. orientalis genotype Ikeda and the Asian longhorned tick in cattle herds from Oklahoma and eastern bordering states. Preliminary results have detected Theileria orientalis genotype Chitose but not Ikeda. No Asian longhorned ticks have been identified. All ticks have either been Amblyomma americanum or Dermacentor species. Additional participation from across the state is needed and encouraged. Cattle producers are urged to take part during fall processing.
Eleven herds have submitted samples thus far, and an additional 20 to 40 farms have the opportunity to participate by submitting blood, ticks, or both. Each participating herd will provide five to 20 blood samples. Herds that test positive to T. orientalis will be followed up with once or twice during the study. Ticks will also be collected from the animals. Tick trapping may also be performed. A maximum of 15 ticks will be analyzed from each sample collection site. All samples will be tested at the Oklahoma Animal Disease Diagnostic Laboratory.
All sampling supplies, shipping labels, and testing are provided at no cost to producers. Samples may be collected by veterinarians or producers with a consulting herd veterinarian. Blood collections will process twice weekly with results emailed to the address on the submission form
and the consulting herd veterinarian. Anaplasma marginale testing will also be provided at no cost, (up to 20 samples per herd) if anaplasmosis is suspected in the herd.
For more information or to participate in the study please contact a member of the research team: Dr. Ruth Scimeca at ruth.scimeca@okstate.edu, Dr. Rosslyn Biggs at rosslyn.biggs@okstate.edu, or Dr. John Gilliam at john.gilliam@okstate.edu.
