Molecular characterization of Theileria orientalis causing fatal infection in crossbred adult bovines of South India

The disease condition attributed to have been caused by Theileria orientalis is generally benign. However, it is also thought that the parasite, at least some strains of it, can cause fatal disease. The present communication deals with the clinical signs, postmortem lesions and diagnosis of a fatal disease due to T. orientalis which caused mortality in crossbred adult bovines of South India. High body temperature, lacrimation, nasal discharge, swollen lymph nodes and haemoglobinuria were the symptoms observed. The postmortem lesions observed were punched out ulcers in abomasum, enlargement of spleen, massive pulmonary oedema, frothy exudates in trachea, epicardial and endocardial haemorrhage and haemorrhagic duodenitis. Peripheral blood smear examination revealed rod shaped Theileria sp. organisms. Polymerase chain reaction that amplify the T. orientalis specific P32/33 gene, followed by cloning and sequencing, revealed maximum homology with Narathiwat (Thailand) and Jingole –1 (Indonesia) isolates which were positioned as isolate type 7 of T. orientalis.

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► Theileria orientalis causing death in crossbred adult bovines of South India.
► Postmortem lesions – abomasal ulcers, pulmonary oedema, haemorrhage in heart.
► Rod shaped T. orientalis organisms in blood smear.
► Sequence analysis of P32/33 gene reveals T. orientalis type 7.