Abstract
To determine the nationwide status of persistent BVDV infection in different bovine species in China and compare different test methods, a total of 1379 serum samples from clinical healthy dairy cattle, beef cattle, yaks (Bos grunniens), and water buffalo (Bubalus bubalis) were collected in eight provinces of China from 2010 to 2013. The samples were analyzed using commercial antibody (Ab) and antigen (Ag) detection kits, and RT-PCR based on the 5’-UTR and Npro gene sequencing. Results showed that the overall positive rates for BVDV Ab, Ag and RT-PCR detection were 58.09% (801/1379), 1.39% (14/1010), and 22.64% (146/645), respectively, while the individual positive rates varied among regions, species, and farms. The average Ab-positive rates for dairy cattle, beef cattle, yaks, and water buffalo were 89.49% (298/333), 63.27% (248/392), 45.38% (236/520), and 14.18% (19/134), respectively, while the Ag-positive rates were 0.00% (0/116), 0.77% (3/392), 0.82% (3/368), and 5.97% (8/134), respectively, and the nucleic acid-positive rates detected by RT-PCR were 32.06% (42/131), 13.00% (26/200), 28.89% (52/180), and 19.40% (26/134), respectively. In addition, the RT-PCR products were sequenced and 124 5’-UTR sequences were obtained. Phylogenetic analysis of the 5’-UTR sequences indicated that all of the 124 BVDV-positive samples were BVDV-1 and subtyped into either BVDV-1b (33.06%), BVDV-1m (49.19%), or a new cluster, designated as BVDV-1u (17.74%). Phylogenetic analysis based on Npro sequences confirmed this novel subtype. In conclusion, this study revealed the prevalence of BVDV-1 in bovine species in China and the dominant subtypes. The high proportion of bovines with detectable viral nucleic acids in the sera, even in the presence of high Ab levels, revealed a serious threat to bovine health.
Highlights
Bovine viral diarrhea virus (BVDV) is a single-stranded positive-sense RNA virus that is a member of the genus Pestivirus [1] and mainly affects cattle, resulting in fever, diarrhea, leucopenia, reduction in milk yield and reproductive problems [2], or no clinical symptoms, but immunosuppression [3]
It is difficult to determine the exact extent of the BVDV epidemic among different bovine species in China due to the variety of detection tests, sampling methods, species, and locations in individual reports
The positive ratio of neutralization Ab in water buffalo averaged 17.25% in some areas [34]. These results demonstrated a high and variable seroprevalence of BVDV-1 among Chinese bovine species
Summary
Bovine viral diarrhea virus (BVDV) is a single-stranded positive-sense RNA virus that is a member of the genus Pestivirus [1] and mainly affects cattle, resulting in fever, diarrhea, leucopenia, reduction in milk yield and reproductive problems [2], or no clinical symptoms, but immunosuppression [3]. The BVDV genome contains a single open reading frame (ORF) encoding a polyprotein that is processed co- and post-transnationally into mature viral proteins. This ORF is flanked with 5’- and 3’- untranslated regions (UTRs). Based on the phylogenetic analysis of partial sequences from the 5’-UTR, the N-terminal autoprotease (Npro) or envelope glycoprotein (E2) region of the genome of this virus is usually divided into two distinct genetic species, namely BVDV-1 and BVDV-2. BVDV-2 was reported to be related to severe hemorrhagic disease, resulting in high mortality, in Canada [20], while BVDV-1 varies in virulence, as most BVDV-1 viruses only cause asymptomatic infection [21]. Recognition of the variability of BVDV field strains is crucial when designing a successful control or eradication scheme at the herd level [6]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
