Coexistence of Multiple Theileria annulata Genotypes Circulating in Neonatal Calves in Semi-arid India

background: Knowledge of local isolates and strains is a prerequisite for the development of either effective mass vaccination strategy or a suitable molecular marker-based diagnostic tool. objective: The pathogenesis of Bovine tropical theileriosis (BTT), caused by Theileria annulata in susceptible ruminants, is known to vary depending upon the nature of isolate and strain involved. Therefore, RFLP and sequencing-based characterization of Indian isolates of T. annulata were attempted using TAMS gene. methods: In the present study, TAMS 1 gene of T. annulata was amplified from 25 naturally infected calves from the BTT endemic semi-arid zone of Northern India. The amplified products were then digested with three restrictions enzymes viz., Taq I, Rsa I, and Alu I to find out the variations in pattern of restriction digests, so as to have an idea about the various isolates of T. annulata present in the studied area. Around 14 samples covering all the variants (from the PCR-RFLP patterns) were sequenced and submitted in NCBI (MH277607-MH277620). results: Coexistence of 4 variant genotypes was detected upon in-silico analysis of RFLP and sequence variations. conclusions: The nucleotide variations alongside the chromatogram analysis revealed point mutations leading to presence of noticeable genetic diversity among the isolates.