Laboratory tests of the VetMAX BVDV Screening RT-PCR test system for detecting the genome of the bovine viral diarrhea virus by ThermoFisher

Relevance. Currently, BVD is widespread in almost all countries of the world with intensive livestock farming. The special relevance of the problem lies in the large economic damage that consists of a decrease in milk yield during the disease, the death of young animals from serous pneumonia, the loss of live weight gain in young animals, the loss of productivity and reproduction of animals and, as a result, abortions and stillbirths, the birth of non-viable calves, as well as preventive, quarantine and liquidation measures. An important link in preventing the spread of viral diarrhea in cattle remains the rapid conduct of laboratory research. One of the most technologically advanced diagnostic methods is real-time polymerase chain reaction.

Methods. The diagnostic significance of the VetMAX BVDV Screening (Thermo Fisher) RT-PCR test system was assessed by sensitivity, specificity, and precision in conditions of repeatability and reproducibility. To determine repeatability, 5 samples of PT-80 cell culture infected with the reference strain "Oregon 24" and 7 samples of PT-80 cell culture infected with Ressa isolate were studied in tenfold dilutions from 10^-1 to 10^-7, by one operator in three parallel studies on the same equipment. To determine reproducibility and sensitivity, 5 samples of PT-80 cell culture infected with the reference strain "Oregon 24" and 7 samples of PT-80 cell culture infected with «Ressa» isolate were studied in ten-fold dilutions from 10^-1 to 10^-7 , by three operators on different days on the same equipment.

To determine the specificity, studies were conducted on 3 samples that did not contain the virus of viral diarrhea — bovine adenovirus type 1 strain Bovina — 10, rhinotracheitis virus of cattle strain "Orenburg" and parainfluenza virus 3 strain ZKSM.

Results. After mathematical processing of the results of PCR formulation for the assessment of reproducibility, the following results were obtained: the coefficient of variation (CV) for the VetMAX BVDV Screening (Thermo Fisher) test system was from 1.0–4.0 %; the Coefficient of variation (CV) for the assessment of repeatability was 1–3 %. The specificity of the test systems VetMAX BVDV Screening (Thermo Fisher) was 100%. The VetMAX BVDV Screening (Thermo Fisher) test system is sensitive to detecting the genome of the bovine viral diarrhea virus. So when setting up PCR samples of the Ressa isolate in the 10^-7 dilution, the CT values were determined at 38.18–39.24 cycles, and the reference VD virus "Oregon 24" in the 10^–5 dilution at 37.85–39.45 amplification cycles.

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