Control of Theileria annulata in Iran.

Tropical theileriosis or Mediterranean Coast Fever - caused by Theileria annulata - is a disease of cattle widely distributed across southern Europe, north Africa and central Asia. Its distribution broadly corresponds with that of its main ixodid tick vectors Hyalomma excavatum and H. detritum (Fig. 1). 'Exotic' cattle (Bos taurus) are particularly susceptible with mortalities up to 40-80% in some areas, whereas indigenous cattle (B. indicus) generally suffer much lower mortalities (about 10%) confined mainly to calves. But because imported non-immune cattle are so susceptible, T. annulata represents a major constraint to livestock improvement programmes in many parts of the middle east and Asia. Cattle that recover from T. annulata infection generally show a solid, long-lasting immunity. For many years there have been programmes to protect cattle by inoculation with blood from sick animals, and more recently using live attenuated T. annulata vaccines prepared from cultured schizont-infected lymphoid cells. This article reviews a 14 year immunization programme against T. annulata in Iran.