title: Comparative evaluation of polymerase chain reaction assay with microscopy for detection of asymptomatic carrier state of theileriosis in a herd of crossbred cattle.
abstract: OBJECTIVE
  This study aims to develop and to standardize a polymerase chain reaction (PCR) assay that will diagnose clinical as well as carrier state of the disease and to compare the results with conventional microscopy technique.
  
  
  METHODS
  A herd of crossbred cattle with the previous history of theileriosis in village Lahli, district Rohtak, Haryana, was selected for this study. A total of 29 blood samples were collected randomly from cows including five clinically ill cattle. Blood smears from all animals and lymph node biopsy smears from animal with swollen lymph nodes were examined microscopically after conventional Giemsa staining. Phenol chloroform isoamyl alcohol method was used for extracting DNA from blood. Previously published primers targetingcytochrome bgene sequence ofTheileria annulatawere used in the PCR assay that was standardized to use in the laboratory.
  
  
  RESULTS
  Out of 29 samples tested,18 (62.06%) were found positive for theileriosis by PCR assay, whereas only 10 (34.48%) samples were detected positive by conventional microscopic technique using Giemsa staining method.
  
  
  CONCLUSIONS
  On the basis results of comparative studies, it can be concluded that PCR assay is a more sensitive than microscopic examination for detection of theileriosis. This can be attributed to the ability of PCR assay to detect small amounts of genomic DNA ofT. annulataor low parasitemia in cows. Therefore, PCR assay can serve as a more sensitive tool to detectTheileriafor detection of theileriosis even in asymptomatic carrier cattle which is important for the implementation of successful control programs.
authors.affiliation: Department of Veterinary Medicine, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, Haryana, India.
authors.forename: Gaurav
authors.initials: G
authors.lastname: Charaya
authors.affiliation: Department of Veterinary Medicine, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, Haryana, India.
authors.forename: N K
authors.initials: NK
authors.lastname: Rakha
authors.affiliation: Department of Animal Biotechnology, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, Haryana, India.
authors.forename: Sushila
authors.initials: S
authors.lastname: Maan
authors.affiliation: Department of Animal Biotechnology, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, Haryana, India.
authors.forename: Aman
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Teaching Veterinary Clinical Complex, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, Haryana, India.
authors.forename: Tarun
authors.initials: T
authors.lastname: Kumar
authors.affiliation: Department of Veterinary Medicine, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, Haryana, India.
authors.forename: Ricky
authors.initials: R
authors.lastname: Jhambh
keywords: Carrier state; Giemsa staining; Theileria annulata; cytochrome b; polymerase chain reaction assay; theileriosis