Comparative Performance and Evaluation of Two Molecular Assays and Conventional Detection of Theileria annulata in Bovines

Abstract

Background: Theileria annulata is predominant and of utmost economical importance tick borne pathogen of bovines in the region which is routinely diagnosed based on the microscopic examination of Romanowsky stained thin blood smears. Present study was intended to evaluate and analyze the detection efficacy of a commercial polymerase chain reaction kit based assay in comparison to conventional PCR assay and classical microscopy for detection of T. annulata from blood samples of bovines from Punjab state. Methods: In this comparative study 360 bovine blood samples from various districts of agro-climatic zones in Punjab were first screened for T. annulata by Giemsa-stained thin blood smear (GSTBS) examination. The same panel of blood samples was tested for T. annulata by a commercial PCR kit Bovi-TheiDX Theileria annulata (Genext Genomics) (PCR1) and established conventional PCR assay targeting merozoite piroplasm surface antigen (Tams1) gene of T. annulata (PCR2). Result: Out of 360 samples screened, positivity of T. annulata by GSTBS was found to be 12.5% (45/360) with a sensitivity of 37.20% and specificity of 96.00% when compared with commercial kit (PCR1), the difference was statistically significant (p less than .0001). The detection prevalence by PCR1 29.70% (107/360) and PCR2 assay 33.90% (122/360) showed significant (p less than .0001) difference. The conventional PCR targeting the Tams1 gene (PCR2) was found to be more sensitive (84.6%) (p less than 0.001) than PCR1 (69.7%).