By Samantha Bartlett

A parasites of red blood cells in cattle has been diagnosed in Kansas. Theileria orientalis Ikeda, detected in Virginia in 2017, has now been identified in 16 states within the U. S. One case in Kansas involved calves that were purchased on the East coast and imported into Kansas. The primary vector is the Asian long-horned tick, a newer invasive species, that has been found in neighboring states including Missouri, Arkansas, and Oklahoma. The disease can be spread through multi-use needles and, of course, the Asian long-horned tick. 

Theileria orientalis is a protozoal parasite that affects red and white blood cells. The parasite causes a condition known as theileriosis with symptoms similar to those of anaplasmosis. Thes include anemia, jaundice, and weakness. T. orientalis is not classified as reportable and there are no known human health risks from the parasite. 

However, the disease caused by T. orientalis can cause significant economic impact for cattle producers secondary to mortality, reduced productivity and increased veterinary costs. It is important to monitor herds for symptoms and call veterinarians as soon as they are noticed to achieve prompt diagnosis and begin management protocols. 

T. orientalis Ikeda has moved steadily across the country and is confirmed in 16 states. The disease mostly affects calves and pregnant heifers and can achieve up to 5 percent mortality rate in an infected herd. Cattle that recover from infection are likely to become chronic carriers and potential disease reservoirs. Infected ticks can remain in pastures for up to two years once introduced.