07/24/2025
To be clear, the tick itself is not the problem for these cattle. The tick is transmitting a protozoan parasite called Theileria orientalis which causes a disease with symptoms similar to bovine anaplasmosis (anemia, weakness, jaundice). Prevention focuses on eliminating tick populations because the tick spreads the parasite from host to host (including domestic animals, wild animals, birds, and humans), and we do not have an effective vaccine for the parasite. Additionally, animals that survive the infection often become carriers of the parasite, so they have to be culled otherwise they can retransmit parasites to the tick and back to the herd. Theileria orientalis has been known in the US for several years, but it has only now become a big problem here in the south. It is not a new disease. The spread of the ticks has been encouraged further into the country by trade and transport of animals, and the strain of Theileria that is predominantly occurring in the US is a particularly lethal one. In other countries where less-lethal strains of Theileria are more common, it's likely that the cattle/wild animals there have some immunity to Theileria organisms due to prior exposure. Also, those countries have approved pesticides that are known to kill this type of tick, which we do not use or have approval for.
Tl;dr: a protozoan parasite carried by ticks is becoming more common in Arkansas cattle as the ticks establish populations here. The most effective method we have is to stop the spread of the ticks to prevent any more populations being established either in the wild or on farms, but the US FDA currently does not have any approved pesticides for use against this tick. Infected animals need to be tested and isolated, and possibly culled. Farms where infection has occurred need to be treated for ticks. Longhorned tick infestations and infections with Theileria orientalis are currently being monitored.
This video has some great information, but it needs a little more detail so that way people can apply it to their own livestock and determine the appropriate risk prevention to take.
Source: USDA Animal and Plant Health Inspection Service