March 2025
Update on Theilieria in the Midwest
By Dr. Gregg A. Hanzlicek
KSVDL has diagnosed Theileria orientalis Ikeda in multiple Missouri and Arkansas operations over the last year.
Although there have been several cases of T. orientalis Ikeda in Kansas, all cases involved cattle imported from the eastern U.S. and not home-raised cattle.
The primary insect vector, Asian longhorned tick, has recently been discovered in an Oklahoma county across the state line from Labette, County Kansas.
Several parasitologists and entomologists have suggested that portions of Kansas possess the climate and vegetation conducive to this tick’s survival.
Positive 2025 Theileria orientalis Ikeda herds identified through testing at KSVDL:
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Bubble size = relative number of positive animals