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In 2019, diarrhea cases occurred on cattle farms in Qionglai and Guang'an, Sichuan Province. Two out of 20 (10%) serum and nasal swab samples were positive when tested using a bovine viral diarrhea virus (BVDV) antigen-capture ELISA kit. Two non-cytopathic strains of BVDV were isolated and named QL1903 and GA190608, respectively. The nucleotide sequences of the genomes of the two isolates were 89.52% identical. Phylogenetic analysis based on the 5'-UTR sequence revealed that the BVDV isolate QL1903 belonged to BVDV subtype 1b, whereas isolate GA190608 clustered with strains HN1814, EN-19, and BJ09_26 in a separate branch, which has tentatively been classified as a new genetic subtype, \"1v\".

Bovine viral diarrhea virus (BVDV) is a major pathogen affecting livestock health in China. However, the current epidemiological status in yaks ( ), particularly in Qinghai Province, remains insufficiently understood. In the present study, a comprehensive serological and molecular investigation of BVDV in yaks was conducted across broad geographic areas of eight administrative regions including Yushu, Guoluo, Huangnan, Hainan, Haidong, Haixi, Haibei, and Xining in Qinghai Province. The results revealed widespread BVDV exposure in Qinghai yak, with an overall antibody prevalence of 84.52% (1158/1370) and substantial herd variation (12.00~98.07%). Active infections were confirmed through antigen detection, revealing prevalence ranging from 0.34% (Haixi) to 4.90% (Huangnan). Genetic characterization identified two circulating subgenotypes: BVDV-1a (n=3) and the predominant BVDV-1u (n=30), with the latter dominating across all regions. These results highlight the endemic circulation of BVDV in Qinghai yak populations and uncover unexpected genetic diversity, emphasizing the need for control measures to mitigate the adverse impacts of BVDV infection in yaks in high-altitude pastoral systems.

Bovine viral diarrhea virus (BVDV) is classified into two species, namely, Bovine viral diarrhea virus 1 and Bovine viral diarrhea virus 2 , and affects cattle worldwide, resulting in significant economic loss. The prevalence of BVDV-1 and BVDV-2 infections and its genotypes in Mongolian animals has not been studied. In this study, we surveyed BVDV infection in dairy cattle and yaks from Bornuur and Bulgan counties by RT-PCR, and the average infection rate in the sampling sites was 15.8 % and 20.0 %, respectively. In addition, molecular features of the 5’-UTR region of the BVDV genome in Mongolian cattle and yaks were identified as belonging to the subtypes BVDV-1a and BVDV-2a, respectively. Determining the prevalence, geographical distribution, and molecular diversity of BVDV-1 and BVDV-2 in various host species in Mongolia is important for further studies and process control programs.

Background Bovine viral diarrhea virus (BVDV) is a pervasive respiratory pathogen of economic concern for the cattle industry. Transplacental infection results in abortion or the establishment of a tolerant and persistent viral infection. Deletion viral genomes (DelVGs) are naturally occurring products of the viral replication process. These deletion viral genomic transcripts are generated with truncations of various sizes that severely impede or prevent self-replication. DelVGs have been implicated in the establishment of viral persistence. Methods We used a bioinformatic pipeline to discover the presence of BVDV DelVGs. These DelVGs were identified via analysis of Illumina MiSeq reads from 74 BVDV1 field isolates from two closely related subgenotypes and from an  in vitro  passage of a BVDV1a virus at two different multiplicities of infection (MOI). Results After the identification of DelVGs, we assessed their phylogenetic linkage to begin elucidating potential roles in the viral life cycle and persistence. BVDV1a viruses queried generate significantly more DelVGs, with 52% of 5’ and 3’ junctions occurring in the core/capsid (C) region and a major NS2-NS5B deletion species. In contrast, the BVDV1b viruses generated significantly fewer DelVGs, especially a reduction in C region deletions. In vitro  passaging of the BVDV1a Singer virus demonstrated that MOI significantly impacts the generation of DelVGs, with higher MOIs generating more DelVGs and a different deletion profile. Conclusions Here, we report that the BVDV1a and BVDV1b subgenotypes generate diverse species of DelVGs. These DelVGs may play key roles in BVDV evolution and the establishment of persistence during transplacental infection.

The objective of this study was to compare reproductive protection in cattle against bovine viral diarrhea virus (BVDV) and bovine herpesvirus 1 (BoHV-1) provided by annual revaccination with multivalent modified-live viral (MLV) vaccine or multivalent combination viral (CV) vaccine containing temperature-sensitive modified-live BoHV-1 and killed BVDV when MLV vaccines were given pre-breeding to nulliparous heifers. Seventy-five beef heifers were allocated into treatment groups A (n=30; two MLV doses pre-breeding, annual revaccination with MLV vaccine), B (n=30; two MLV doses pre-breeding, annual revaccination with CV vaccine) and C (n=15; saline in lieu of vaccine). Heifers were administered treatments on days 0 (weaning), 183 (pre-breeding), 366 (first gestation), and 738 (second gestation). After first calving, primiparous cows were bred, with pregnancy assessment on day 715. At that time, 24 group A heifers (23 pregnancies), 23 group B heifers (22 pregnancies), and 15 group C heifers (15 pregnancies) were commingled with six persistently infected (PI) cattle for 16days. Ninety-nine days after PI removal, cows were intravenously inoculated with BoHV-1. All fetuses and live offspring were assessed for BVDV and BoHV-1. Abortions occurred in 3/23 group A cows, 1/22 group B cows, and 11/15 group C cows. Fetal infection with BVDV or BoHV-1 occurred in 4/23 group A offspring, 0/22 group B offspring, and 15/15 group C offspring. This research demonstrates efficacy of administering two pre-breeding doses of MLV vaccine with annual revaccination using CV vaccine to prevent fetal loss due to exposure to BVDV and BoHV-1.

The SD0803 strain of the bovine viral diarrhea virus (BVDV) was isolated from a piglet in China in 2008 and has been classified as a novel subgenotype of BVDV-1. To describe the molecular features of this novel subgenotype, we sequenced and characterized the complete genome of the SD0803 virus. The genome is 12,271 bp in length and contains 5′ and 3′ untranslated regions (UTRs) that flank an open reading frame (ORF) encoding a 3,898-amino-acid polypeptide. The full-length genome of the SD0803 strain shares 78.8 % to 83.3 % identity with those of other BVDV-1 strains, 70.0 % to 70.7 % identity with those of BVDV-2 strains, and less than 67.6 % identity with those of other pestiviruses. The highest level of shared identity was 83.3 % between the complete SD0803 genome and that of the ZM-95 strain of BVDV-1. Phylogenetic analysis of the 5′ UTR and the coding sequence for the N-terminal protease fragment of the SD0803 polyprotein indicated that the SD0803 virus is a member of the novel subgenotype BVDV-1q, isolates of which have been identified recently in dairy cattle and camels in China.

Bovine viral diarrhea virus (BVDV) is a worldwide spreading pestivirus affecting cattle and other ruminants; however, there have been few reports on epidemiologic investigation of BVDV in eastern China. In this study, bulk tank milk from 36 herds of dairy cattle in eastern China was submitted to serological investigations, 77.8% of herds was BVDV antibody positive. Individual animal status in two herds was further investigated collecting blood samples, the positive ratio was 49.74% and 24.64%, and the average positive ratio of calves, heifers, and lactating cows was 15.94%, 40.16%, and 41.7%, respectively. Moreover, clinical survey was carried out among 8170 dairy cattle from 36 herds, for diarrhea syndrome, respiratory problems and reproductive failure, and pathogens of all clinical cattle were further investigated. The results showed that BVDV was one of the main pathogen, which infected animals combining with various other viruses. Then, nine BVDV strains were isolated; phylogenetic analysis showed that BVDV subtypes currently circulating in eastern China were BVDV 1a and BVDV 1c. In addition, out of 377 cows tested, the 1.86% detected positive to the BVDV antigen. This study provided the foundation of further study on vaccination and control strategies of BVDV in eastern China.

BACKGROUND: Bovine viral diarrhea virus (BVDV) is one of the most important pathogens in cattle. Previously, BVDV sub-genotypes of 1b, 1c, 1d, and 1 m were detected in China. However, isolation of BVDV type 1a from cattle has not been reported in China. In 2010, twenty nasal swabs and blood samples were collected from the cattle suspected BVDV infection in Henan province, China. A BVDV isolate was isolated using cell culture, and the pathogenesis of the virus isolate was studied. METHODS: Virus isolation was performed on MDBK cells. The virus identification was conducted by RT-PCR, neutralization test and immunofluorescence assay. In order to determine the genotype of the newly isolated virus, the 5′ un-translated region (5′UTR) of the virus isolate was cloned, sequenced and phylogenetically analyzed. To evaluate the virulence of the virus isolate, four BVDV sero-negative calves were intranasally inoculated with the virus suspension. Rectal temperatures and clinical signs were recorded daily. Blood samples were analyzed for changes in white blood cell counts, and tissue samples were taken for histopathology analysis. RESULTS: A new isolate of bovine viral diarrhea virus (BVDV), named HN01, was isolated from the nasal swabs using MDBK cell culture. The HN01 strain caused cytopathic effect (CPE) in MDBK cell cultures after two passages. The virus specifically reacted to BVDV1-specific monoclonal antibody in an immunofluorescence assay. A fragment of 288 bp of genome from this isolate was amplified by the RT-PCR. Phylogenetic analysis of 5′UTR indicated that the virus was BVDV 1a. In the pathogenesis study, four calves experimentally infected with the BVDV strain developed depression, cough and other clinical signs. Calves showed high temperature over 40°C, and white blood cell counts dropped more than 40%. CONCLUSIONS: A new subgenotype 1a strain of BVDV was firstly isolated from dairy cattle in China. The experimental infection showed that the virus was moderate pathogenic to cattle and can be used as a BVDV challenge virus to evaluate the efficacy of BVDV vaccines in the target animals.

A part of the nucleotide sequence of the 5' untranslated region (5'UTR) and Erns region, and the genomic regions encoding for Npro, Core, and E2 of So-like isolates and IS25CP/01 strain which belong to bovine viral diarrhea virus genotype 1 (BVDV-1) were determined and genetic comparisons were made with sequences of other BVDV subgenotypes. Phylogenetic analysis using the 5'UTR and Npro revealed that So-like isolates and IS25CP/01 branched into independent phylogenetic branch. So-like isolates were clustered with Korean BVDV strains taken from DDBL/EMBL/GenBank in the 5'UTR. An additional two amino acid residues were found at the C terminal of the Core region of IS25CP/01. The similarity of amino acid sequence of E2 of So-like isolates and IS25CP/01 to the BVDV-1 reference strain NADL were 78.0-78.5 and 79.0, respectively. Cross-neutralization tests showed significant antigenic differences between So-like isolates and the others (Antigenic similarity (R) value: 2.2-8.8), and IS25CP/01 and the others (R value: 1.6-8.8). So-like viruses and IS25CP/01 differed from the thirteenth subgenotypes (1a-1m) reported by Jackova et al. (2007) and were classified as new genetic subtypes, BVDV-1n (So-like) and 1o (IS25CP/01).

Sequence-based genotyping was recently used to distinguish between the BVDV-1 and BVDV-2 species of the bovine viral diarrhoea virus ( BVDV ). Quite recently, a new putative species, BVDV-3, was also detected. The phylogenetic analysis of the 5′-untranslated region (UTR) and Npro region has revealed at least 17 distinct subtypes for BVDV-1 to date. The aim of this study was to further investigate the genetic heterogeneity of BVDV-1 in Italy, by analysing 173 virus sequences from isolates collected over an 18-year period (1997–2014). Viral RNA was extracted from the original biological samples identified as BVDV-1-positive. Reverse transcription (RT) and polymerase chain reaction (PCR) assays targeting a 288-base pair (bp) region of the 5′-UTR and a 428-bp region encoding the autoprotease Npro were performed, and the RT-PCR products were sequenced. The phylogenetic analysis of the 5′-UTR and Npro sequences re-confirmed the circulation of ten out of eleven subtypes previously discovered in Italy. Interestingly, four isolates differed significantly from all of the bovine pestiviruses identified so far, thereby providing evidence for the circulation of three novel subtypes that have not been documented so far. The growing number of reports on BVDV-1 heterogeneity, including the recent findings reported herein, raises concern related to the emergence and spread of new BVDV variants, with possible implications for animal health and disease control. This global issue needs to be addressed with the highest priority.