April 18, 2024


Missouri, US cattle producers urged to watch for symptoms in animals associated with protozoal organism




Cattle producers in Missouri, the United States, should watch for signs of disease associated with Theileria orientalis (ikeda), a protozoal organism recently detected in the state, according to the University of Missouri's director of Veterinary Extension, Craig Payne.


This organism, which primarily affects cattle, causes disease by infecting red blood cells. The immune system attacks the infected cells, resulting in anemia.


First discovered in 2017 in the US, it has been found in nine US states, including Missouri. Payne said that as of March 1, there were six counties in Missouri where cattle have tested positive.


With mild infections, cattle may show elevated temperature, depression and pale mucous membranes. With severe infections, they can show severe depression and the mucous membranes around eyes and the vulva appear jaundiced with a yellow tinge.


Pregnant animals may abort and animals will lose body condition. Payne noted that most infected cattle never show symptoms, and death loss rates are typically less than 5%.


The main route of transmission of the disease is through the Asian longhorned tick. Blood-contaminated equipment can also transfer the organism from infected to uninfected animals. Up to 10% of calves born to infected animals may carry the organism.


Once transmitted, symptoms appear in one to eight weeks.


Infected animals will become lifelong carriers of the organism but are unlikely to show symptoms of disease again. Culling these chronic carriers from a herd may be warranted if disease prevalence is low, said Payne.


He stated there are currently no vaccines available to prevent the disease.


- Beef Magazine

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