Comparison of parasitological, serological and molecular diagnostic tests for detection of subclinical Trypanosomosis in two organised dairy herds

อังกฤษ

Buffaloes;Bubalus bubalis;Trypanosomosis;Diagnosis;Subclinical infection;TE-LAT;PCR assay

Trypanosomosis also known as 'Surra' caused by Trypanosoma evansi is of significant economic importance in livestock production. Diagnosis of subclinical infection and carrier state of disease is far difficult. Therefore, the present study was conducted to compare parasitological, serological and molecular diagnostic tests for detecting subclinical trypanosomosis in two dairy herds of Murrah buffalo (n=27) and crossbred cattle (n=22) in Hisar district of Haryana. Peripheral blood samples collected from all the animals were subjected to blood smear examination and DNA isolation for molecular detection by PCR, and like-wise serum samples were collected and subjected to latex agglutination test (TE-LAT) for T. evansi antigen detection. PCR products from positive samples were purified and sequenced for confirmation of T. evansi DNA. None of the animals in the two herds was found positive for T. evansi parasites by microscopic examination of thick blood smears. In buffalo farm, 29.62 percent samples each were found moderately and weak positive by TE-LAT, whereas PCR assay test yielded 40.74 percent samples positive for T. evansi DNA. In cattle farm, TE-LAT showed 18.18 percent, 31.89 percent and 9.09 percent samples to be strong, moderate and weak positive, whereas 50 percent samples were found PCR-positive for T. evansi DNA. Agreement among TE-LAT and PCR assay, as expressed by the kappa value, was found to be poor. To conclude, each test has its own merits and limitations. While TE-LAT is suitable for screening purpose, PCR assay confirms parasite in blood. For clinical diagnosis, results of laboratory diagnostic tests must, however, be correlated clinically before initiating the therapy.

[1] Gaurav Charaya (Lala Lajpat Rai University of Veterinary and Animal Sciences, Haryana (India). Department of Veterinary Medicine)
[2] Naresh Kumar Rakha (Lala Lajpat Rai University of Veterinary and Animal Sciences, Haryana (India). Department of Veterinary Medicine)
[3] Aman Kumar (Lala Lajpat Rai University of Veterinary and Animal Sciences, Haryana (India). Department of Animal Biotechnology)
[4] Akhil Kumar Gupta (Lala Lajpat Rai University of Veterinary and Animal Sciences, Haryana (India). Department of Veterinary Microbiology)
[5] Sushila Maan (Lala Lajpat Rai University of Veterinary and Animal Sciences, Haryana (India). Department of Animal Biotechnology)
[6] Ajit Singh (Lala Lajpat Rai University of Veterinary and Animal Sciences, Haryana (India). Department of Veterinary Microbiology)
[7] Parveen Goel (Lala Lajpat Rai University of Veterinary and Animal Sciences, Haryana (India))