Theileria parasite infections are the greatest impediment to the development of live stock industry in developing countries. Theileria annulata causes bovine tropical theileriosis in North African, West African, South European and most Asian countries including India, China and Southern Russia. Bovine tropical theileriosis is being controlled by eliminating ticks by using acaricides and by schizont cell culture vaccine in many countries.

Bovine theileiosis caused by T. sergenti is less pathogenic of Theileria species and has been reported to cause anaemia in cattle in Japan, Korea and some of the other East Asian countries. Antigenic and genetic diversities of different isolates were observed. Major piroplasm surface antigen has been used now with a considerable degree of success in immunising cattle.