Title : Identification of Hobi like pestivirus as a contaminant of the vaccine against peste des petits ruminants
Abstract:
Introduction and objective: Along with the success of developing biological products of new generation the traditional vaccines, as well as hyperimmune sera, remain as the main means of preventing viral diseases in animals. However, there is a potential threat of the dissemination of emergent infections in a case of insufficient control in the production of animal origin products. It has been already confirmed almost all around the world that pestiviruses are frequent contaminants of live modified vaccines and fetal serum, which induce infection in the organism of animals.
Hobi- like virus or Pestivirus H is one of the 11 main viral species of the genus Pestivirus in the Flaviviridae family. This virus was first identified in 2004 in a batch of bovine fetal serum. This research presents the results of the detection of the Hobi-like pestivirus in the virus vaccine against PPRV used for the vaccination of small ruminants in some farms of the Republic of Tajikistan.
Materials and methods: The studies were carried out in the laboratory of virology of the FSC VIEV. Serum samples of sheep and goats with symptoms of respiratory and reproductive failure from some regions of Republic of Tajikistan were tested by AGID. The vaccine strain of PPRV and strain “Oregon C24V” of BVDV was used as the control antigens. The total RNA was extracted by the commercial kit Syntol (Moscow, Russia) according to the manufacturer’s protocol. RT-PCR for the identification of N and F genes of PPRV and NS3 genes of BVDV was performed in accordance with the recommendations of the OIE Terrestrial Manual, 2013. Viruses were sequenced and phylogenetic analysis carried out using MEGA 7.0.
Results: It has been obtained a positive result when PPRV vaccine strain was used as an antigen. A precipitation line formed between the well with the PPR vaccine and the well with the field serum indicated the presence of antibodies to the PPR virus. In some cases, when examining blood serum samples from sheep and goats with a commercial virus vaccine against PPR, double precipitation lines were observed. In this stage of the study, it has been assumed that the vaccine against PPR contained two viruses. Consequently, we had tested the commercial vaccine used in the Republic of Tajikistan for the presence of contamination. The results of RT-PCR had shown that in addition to the PPR virus, the vaccine contains the genome of bovine viral diarrhea virus (BVDV). When sequencing the amplification products, it was determined that the detected virus belongs to the BVDV genotype 3 or the so-called Hobi-like pestivirus. The sequences of detected virus were deposited to GenBank under accession number KX900607
