Comparison of different PCR protocols and respective primer sets from pool of TAMS 1 gene for diagnosis of calf theileriosis from semi arid India.

The polymorphic nature of Theileria annulata merozoite surface antigen (TAMS 1) attributes to limitation in PCR based detection of various T. annulata genotypes present in different geographical domains across the globe. Multiple reports of failure of detection of tropical theileriosis using classical N516/517 primer set in the studied area were noticed. Hence, three single PCR protocols using N516/517, TAMS F/R and NTA F/R primer sets encoding different portions of TAMS 1 gene and two nested protocols, using combinations of these three primers, were compared to find out the most suitable primer set for diagnosis of calf theileriosis in studied area. The studied area constitutes the semi-arid theileriosis endemic area of Northern India. The various PCR protocols were tested on 75 clinically confirmed cases of calf theileriosis. Alongside, 25 confirmed theileriosis negative blood samples and DNA of other haemoprotozoa were also tested for specificity of these primer sets. Results revealed that the primer set NTA F/R to be more suitable in detecting the circulating T. annulata genotypes in the studied area in comparison to the classical N516/517 primer set. None of the primers gave false positive amplification with negative samples and/or DNA of other haemoprotozoa.