Isolation of BVDV-1a, 1m, and 1v strains from diarrheal calf in china and identification of its genome sequence and cattle virulence

Abstract

Bovine viral diarrhea virus (BVDV) is an important livestock viral pathogen responsible for causing significant economic losses. The emerging and novel BVDV isolates are clinically and biologically important, as there are highly antigenic diverse and pathogenic differences among BVDV genotypes. However, no study has yet compared the virulence of predominant genotype isolates (BVDV-1a, 1b, and 1m) in China and the emerging genotype isolate BVDV-1v. The serological relationship among these genotypes has not yet been described. In this study, we isolated three BVDV isolates from calves with severe diarrhea, characterized as BVDV-1a, 1m, and novel 1v, based on multiple genomic regions [including 5-untranslated region (5′-UTR), Npro, and E2] and the phylogenetic analysis of nearly complete genomes. For the novel genotype, genetic variation analysis of the E2 protein of the BVDV-1v HB-03 strain indicates multiple amino acid mutation sites, including potential host cell-binding sites and neutralizing epitopes. Recombination analysis of the BVDV-1v HB-03 strain hinted at the possible occurrence of cross-genotypes (among 1m, 1o, and 1q) and cross-geographical region transmission events. To compare the pathogenic characters and virulence among these BVDV-1 genotypes, newborn calves uninfected with common pathogens were infected intranasally with BVDV isolates. The calves infected with the three genotype isolates show different symptom severities (diarrhea, fever, slowing weight gain, virus shedding, leukopenia, viremia, and immune-related tissue damage). In addition, these infected calves also showed bovine respiratory disease complexes (BRDCs), such as nasal discharge, coughing, abnormal breathing, and lung damage. Based on assessing different parameters, BVDV-1m HB-01 is identified as a highly virulent strain, and BVDV-1a HN-03 and BVDV-1v HB-03 are both identified as moderately virulent strains. Furthermore, the cross-neutralization test demonstrated the antigenic diversity among these Chinese genotypes (1a, 1m, and 1v). Our findings illustrated the genetic evolution characteristics of the emerging genotype and the pathogenic mechanism and antigenic diversity of different genotype strains, These findings also provided an excellent vaccine candidate strain and a suitable BVDV challenge strain for the comprehensive prevention and control of BVDV.

Pestivirus A Bovine viral diarrhea virus type 1 species genotypes circulating in China and Turkey.

“…Subsequently, the genotype BVDV-1.19 (1g), with a mean divergence value in the genus of 3.5 bp, was renamed 1.20, and the genotypes BVDV-1.20 (1l or x), BVDV-1.21 (1u), BVDV-1.22 (1k), and BVDV-1.23, with a divergence in the genus higher than 5 bp, were renamed as 1.22, 1.23, 1.24, and 1.25. Details of the computing of divergence values (exceeding limit value 9 for genotype determination) based on 5′-UTR secondary structure sequence alignment of BVDV-1 bovine strains EN-6, T4-32, T4-31-2, GA190608, BJ09_26, HY-3, and HN1626, HB-03, XH-1, MF-3 and one goat strain JS12/02, reported as genotype 1o or 1v isolated from China ( Mao et al , 2016 ; Deng et al , 2020 ; Shi et al , 2020 ; Tian et al , 2021 ; Zhu et al , 2022 ; strain T6-18, reported as genotype 1w isolated from China ( Deng et al , 2020 ), strains TY8723, TR-Erz-Pst8, TRElz-4-2021, TR-Elz-Pst16, IRTV1, and IR-Shiraz-322, reported as genotype 1a, 1l, or 1v, isolated from Turkey and Iran ( Oguzoglu et al , 2019 ; Timurkan and Aydin, 2019 ; clustered according to PNS method as 1.7.3, 1.19, and 1.21, respectively are presented in Supplementary Material 1 .…”

“…While genotype 1.19 (1w) constituted a separate group in the species, reported in China more recently in 2017 ( Deng et al , 2020 ), the Chinese group of strains reported as 1v ( Deng et al , 2020 ; Tian et al , 2021 ; Zhu et al , 2022 ) and those reported as 1o and considered as 1v ( Shi et al , 2020 ; was related to genotype 1.7 (1o) and constituting a new sub genotype (1.7.3). This corresponded to the observation made by Shi et al (2020) , who reported nine Pestivirus A isolates as putative new 1o sub genotype, based on phylogenetic analysis of partial 5′-UTR and Npro sequences.…”

“…The virus nucleotide sequences, with different geographical origin from different host species or contaminants of biological products, were obtained from the DDBL/EMBL/GenBank DNA database ( Table 1 ). The majority of the tested virus sequences originated from strains isolated from cattle ( Bos taurus ) from China ( n = 29) ( Deng et al , 2020 ; Shi et al , 2020 ; Tian et al , 2021 ; Zhu et al , 2022 ; from Turkey ( n = 25) ( Oguzoglu et al , 2019 ; Timurkan and Aydin, 2019 ; and from Iran ( n = 5). In addition, two strains were isolated in small ruminants ( Capra hircus ) from China ( Mao et al , 2016 ).…”

Immune evasion strategies of bovine viral diarrhea virus

“…The cp BVDV is characterized by the constructive expression of NS3, while ncp BVDV strains produce a fusion of NS2 and NS3 proteins named NS2-3 ( Darweesh et al., 2015 ). BVDV infection causes variable symptoms including growth retardation, hemorrhaging, respiratory and gastrointestinal disorders, reproductive failures, persistent infection, and lethal mucosal disease (MD) ( Mirosław et al., 2022 ; Zhu et al., 2022 ).…”

Diagnosis of bovine viral diarrhea virus: an overview of currently available methods

“…This classification accurately reproduces the subtyping of all the 118 BVDV-1 and 88 BVDV-2 complete/near-complete genomes (CNCGs) from GenBank (Mucellini et al, 2023). BVDV is classified into three genotypes, BVDV-1 (Pestivirus A), BVDV-2 (Pestivirus B), and BVDV-3 (Pestivirus H or HoBi-like virus), in which BVDV-1 currently contains at least 22 subtypes (1a-1v) and BVDV-2 contains at least 4 subtypes (2a-2d) (de Oliveira et al, 2021;Zhu et al, 2022). The single ORF encodes a large polyprotein that is post-translationally cleaved into four structural proteins (C, E rns , E1, E2) and eight non-structural proteins (N pro , p7, NS2, NS3, NS4A, NS4B, NS5A, NS5B) in ncp BVDV isolates (Chi et al, 2022).…”