Tick-Borne Disease Threatens US Cattle

REDFIELD, Iowa (DTN) -- While relatively new to the United States, Theileria orientalis has begun spreading quickly, leaving infected cattle herds in several states. The disease is spread by the Asian longhorned tick, which is arriving in areas carrying the protozoa and infecting naive animals. "There are several genotypes of Theileria orientalis, but the one we are most concerned with in the cattle industry is the Ikeda genotype," said Craig Payne, University of Missouri director of Veterinary Medical Extension and Continuing Education. "Sometimes this disease will be mistaken for anaplasmosis." A diagnostic test will reveal differently. Payne said a misdiagnosis could mean Theileria has been circulating in a herd longer than thought. The first diagnosis of Theileria was in a Virginia cow-calf herd in 2017. DISEASE SYMPTOMS Cattle with Theileria show lethargy, anemia and difficulty breathing. Payne explained that the protozoa infects red blood cells. "These infected cells are ...