Theileria orientalis genotype Ikeda: An Emerging Cattle Disease?

By Barry Whitworth, DVM

Theileria orientalis genotype Ikeda is a hemoprotozoan. A hemoprotozoan affects red blood cells and leukocytes. T. orientalis genotype Ikeda has been associated with severe bovine disease in Japan, New Zealand and Australia (Watts, Playford, & Hickey, 2016). In August 2017, the protozoan was found associated with illness and death in cattle at a ranch in Virginia (Oakes et al., 2019). These cattle displayed clinical signs of weakness and anemia. A preliminary diagnosis of anaplasmosis was given. Blood samples taken from the animals were tested for Anaplasma, Babesia and Leptospira. Results from the test revealed the cattle were all negative; however, a blood protozoan was detected. This protozoan was identified as T. orientalis genotype Ikeda (Oakes et. al, 2019). Since this original herd outbreak, other herds of cattle in Virginia and West Virginia have been found to be infected with the organism.

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