Investigations on First Confirmed Outbreak of Ovine Theileriosis (Theileria luwenshuni) from Maharashtra State, India

Abstract

Background: Clinical theileriosis of small ruminants is tick-borne disease caused by Theileria lestoquardi, Theileria uilenbergi and Theileria luwenshuni. Theileria annulata, the causative agent of bovine tropical theileriosis in cattle, can also infect sheep but does not cause any significant illness. It is one of the economically important diseases. There are no reports of ovine clinical theileriosis from Maharashtra state and there is paucity of information on its epidemiology. This paper reports first confirmed outbreak of ovine theileriosis based on clinical signs, microscopic examination, PCR and sequencing in the Maharashtra State of India. Methods: Whole blood samples from 22 ailing sheep were collected and subjected to hematological examination. Blood smears stained with Leishman’s stain were examined under 100X objective of the microscope. The blood samples from sheep found positive by microscopic method were subjected to PCR detection of 18S rRNA gene of hemoprotozoa and then for nucleotide sequencing and sequence analysis.Conclusion: Samples from 14 out of 22 sheep were found positive for piroplasms of Theileria spp by light microscopy. All positive samples were further confirmed by PCR detection of 18S rRNA gene of hemoprotozoa. PCR amplification yielded expected product of 1750 bp for all samples. BLAST and phylogenetic analysis of one sample revealed high sequence homology with T. luwenshuni reported from India and other countries. Characteristic clinical signs like fever, progressive anaemia, laboured breathing, lymphadenopathy, debility and non-responsiveness to antibiotic therapy were recorded. The animals responded to specific treatment against theileriosis. It is the first ever confirmed report of ovine theileriosis in Maharashtra state of India and hence reported.