East coast fever in cattle is caused by

Answer: Option A

East coast fever in cattle is caused by Theileria.
East Coast fever, also known as theileriosis, is a disease of cattle that occurs in Africa and is caused by the protozoan parasite Theileria parva.
This disease was first reported in southern Africa, south of the Zambezi river, in 1902. It became known as East Coast fever after it was determined that the disease had originated in cattle imported from the East Coast of Africa.