June 26, 2023
Protect Your Cattle from Asian Longhorned Ticks and Theileriosis
Management of tick populations key to slowing parasite
Contact: Shelby Crouch

The Asian Longhorned tick (ALT), which was first discovered in the United States in 2017 has now be found in 19 states including Virginia. Currently, there are 38 Virginia counties with established ALT populations. As ALT populations have increased, a concern for the health of livestock in affected areas has increased as well. ALT is a vector for the parasite Theileria orientalis Ikeda which can cause theileriosis in livestock, including cattle.

“When cattle develop theileriosis, signs of anemia, fever, jaundice, difficulty breathing and lethargy can be present,” said Dr. Charles Broaddus, VDACS State Veterinarian. “As there is no cure, treatment should focus on supportive measures including stress reduction, nutritional supplementation and above all, prevention in the form of tick control.”

Once symptoms of theileriosis manifest, testing is an important step to confirm the presence of Theileria orientalis. Dr. Kevin Lahmers of the Virginia-Maryland College of Veterinary Medicine (VMCVM) has been leading research on this new pathogen, and Virginia Tech Animal Laboratory Services (ViTALS) at VMCVM has developed a PCR test for Theileria orientalis and Anaplasma marginale. This is performed on whole blood in EDTA in live animals but can be run on fresh spleen as well. Samples can be submitted directly to ViTALS vitals.vetmed.vt.edu or through VDACS lab services. Dr. Lahmers can be reached at klahmers@vt.edu or 540.231.4320.

Dr. Lahmers noted, “The VMCVM is happy to partner with VDACS to work together to address this important emerging disease that has hit our region.”

As there is no approved treatment in the U.S., controlling ALT populations is the best management option. Virginia Cooperative Extension has developed the following methods to manage ALT populations:

• Regularly inspect cattle for ticks. As ALT is very small, a thorough inspection is required.
• During inspections, pay close attention to cattle that appear lethargic or anemic, have low weight, or have patchy hair.
• Inspect all newly purchased cattle before adding to a herd.
• Submit tick samples to your local extension agent for species confirmation.
• Consider using pesticide-impregnated ear-tags.
• Use backrubbers and siderubbers charged with appropriate pesticides in high traffic areas.
• For treatment in areas of high tick concentrations, use direct pour-on treatments.
• Treat all animals in a herd for ticks at the same time.
• Consider keeping pastures mowed shorter.
• Consider keeping cattle out of wooded areas.
• Check any pets or working animals that are in contact with herds.

Click here for more management practices. Remember to always act in accordance with labeling when using any pesticide product.

The USDA has authorized theileriosis to be included on the list of diseases eligible for their Livestock Indemnity Program. Please contact your local USDA Farm Service Agency for more information about this program.

Currently there are no movement restrictions of Virginia cattle across state lines and this disease represents no threat to human health.

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