Emergence and Variations in Disease Ecology of Tick-Borne Bovine Theileriosis in East India

Abstract

Bovine theileriosis is one of the economically important tick-borne disease (TBD) of bovine limiting livestock production in Eastern India. There has been a massive concern for livestock farmers owing to its involvement in heavy economic losses, often salient in nature, associated with multiple pathogens and difficulty in symptomatic diagnosis. Approximate estimates of annual losses due to these tick-borne diseases in India is about ₹4353.0 crore. The bovines in East India are reported to suffer from theileriosis by two species, i.e. Theileria annulata and Theileria orientalis. Report from AICRP on ADMAS Annual Report 2015-16, NIVEDI Bangalore suggest that highest outbreaks of theileriosis were from Jharkhand in the whole country and moderate reports of the outbreak from Eastern states of Odisha, West Bengal, and Assam. In Chhattisgarh state, the prevalence of theileriosis reported as high as 23.3 % in random samples cattle population. Species difference exists relative to clinical manifestations of tropical theileriosis with exotic cattle and their crosses. Yak is most susceptible animal as compared to Bos indicus, camel and buffalo are considered to be the natural hosts in which the parasite evolved and they may also act as carriers. Pathogenesis in bovine is related to different stages of the parasite in the host and causing damage to lymphoid and red blood cells. Clinical symptoms with a history of the tick infestation can be suggestive of theileriosis. However, definitive diagnosis required laboratory testing using Giemsa stained blood smears (GSBS). Though new modern diagnostic methods have developed, GSBS is the most common diagnostic method in practice. Treatment and control of TBDs can be achieved by the use of biological agents, genetic selection, chemotherapy, and vaccines. Tick control is another crucial strategy to limit TBDs, including theileriosis.