The Iowa Department of Agriculture has confirmed the first known case of Theileriosis in an Iowa cattle herd. The disease, caused by the parasite Theileria orientalis Ikeda, was found in a herd in southeast Iowa and poses a serious threat to livestock health.
Theileriosis is spread by the Asian Longhorned Tick, an invasive species recently detected in the state. The parasite attacks red and white blood cells, leading to anemia, breathing problems, jaundice, and even death—especially in young cattle. The tick population is expected to increase during the summer months, particularly when cattle are first turned out to pasture.
Producers in southern Iowa—and eventually farther north—are being urged to keep a close eye on their herds for signs of tick infestation or illness. Symptoms may resemble anaplasmosis but tend to be more severe in calves. If illness or ticks are spotted, farmers should contact a veterinarian and have samples sent to the Iowa State Veterinary Diagnostic Lab.
Officials stress that basic insecticide ear tags aren’t enough to protect livestock from ticks. Producers are encouraged to use a combination of control methods, including backrubbers, pour-on treatments, and tick-specific insecticides. In heavy infestations, an avermectin-based pour-on may be the most effective solution.
While the disease is dangerous to cattle and other hoofed animals, there is no risk to humans.
For more information and prevention tips, visit the Iowa Department of Agriculture’s website.
