Retrospective genome analysis of a live vaccine strain of bovine viral diarrhea virus

Abstract

-A live bovine viral diarrhea (BVDV) vaccine, marketed as a derivate of the Oregon C24V strain, was used between the end of the 1960s and the beginning of the 1990s in Central Europe. Since laboratory investigations of mucosal disease cases in vaccinated animals suggested recombinations between the vaccine and wild type variants of BVDV, and recombinational nucleotide sequences seemed distinct from BVDV Oregon C24V, the aim of the present retrospective study was to analyze the genomes of pre-registration (termed here BVDV-Xpre) and of marketed (BVDV-X) batches of the vaccine. The results of the complete genome analysis of BVDV-Xpre confirmed that the original virus strain used at the start of the vaccine production was Oregon C24V. Surprisingly, the analysis of the complete nucleotide sequence of the BVDV-X marketed vaccine revealed that this strain belongs to the BVDV 1b subgroup, with a 93.7% nucleotide sequence homology to BVDV reference strain Osloss. The homology to BVDV Oregon C24V was significantly lower (77.4%), and a thorough sequence scanning showed that the genome of BVDV-X had not derived from Oregon C24V. These data indicate the very likely scenario that a strain different to Oregon C24V was picked up during the in vitro or in vivo passages for vaccine development. Despite of the virus-switch, the BVDV-X vaccine continuously maintained its innocuity and efficacy, as proven by the regular quality testing data, and the presence of the foreign virus remained unnoticed over many years. The results of this work emphasize that the contamination of commercially available live vaccines with exogenous BVDV strains is a real risk factor, and a unequivocal analysis, including molecular methods, is needed to verify their authenticity. bovine viral diarrhea virus / vaccine / strain switch / control

A 45-Nucleotide Insertion in the NS2 Gene is Responsible for the Cytopathogenicity of a Bovine Viral Diarrhoea Virus Strain

“…These cases occurred after vaccination with a live attenuated vaccine, termed here for ethical reasons BVDV-X [22]. The NS2-3 genes of the vaccine virus and of the MD isolates were found to be identical.…”

“…Therefore, research activity was focused on BVDV-X. The complete nucleotide sequence of the marketed vaccine virus BVDV-X was determined, and sequence analysis did not reveal further genetic changes contributing to the cytopathogenicity of BVDV-X [24]. Furthermore, expression studies revealed that the insertion induces NS2-3 cleavage [22].…”

“…The complete nucleotide sequence of the marketed vaccine virus BVDV-X was determined, and sequence analysis did not reveal further genetic changes contributing to the cytopathogenicity of BVDV-X [24]. Furthermore, expression studies revealed that the insertion induces NS2-3 cleavage [22]. In order to determine the role of this insertion in cytopathogenicity of BVDV-X, the aims of this study were: (i) construction of a full-length infectious cDNA clone of BVDV-X and characterisation of the recovered virus; (ii) deletion of the insertion in context of the full-length clone to prove that the insertion-negative mutant virus switches to the ncp phenotype.…”

Molecular investigation of bovine viral diarrhea virus infection in yaks (Bos gruniens) from Qinghai, China

“…Surprisingly, four yaks from two counties were infected with BVDV-1b strains that were closely related to sequences from a BVDV vaccine Vedevac, with strong support in both the 5′UTR and N pro phylogenies. Vedevac was found as the main virus strain in batches of BVDV vaccine Oregon C24V in Hungary, and it was likely to have been picked up accidently during passages of the original Oregon C24V for vaccine development between the 1960s and 1990s [33]. In China, the Oregon C24V vaccine has been distributed to different laboratories as a reference strain for BVDV, but it has never been used for vaccination against BVDV in yaks in this region.…”

Cytopathic bovine viral diarrhea viruses (BVDV): emerging pestiviruses doomed to extinction

“…2) which we found in bovine cells prepared in Kenya with local serum [10]. Thus, it would come as no surprise if many laboratories working with cell cultures of ruminants unwittingly propagate pestiviruses (see, e.g., [4, 7, 62, 96], and unpublished observation). The taxonomy of pestiviruses is constantly changing, partly because of the discovery of new pestiviruses, but also because the criteria for the allocation of species status and division in subgroups within a given species (Fig.…”