Evidence of BVDV in Pigs from North Eastern Part of India- Genetic Profiling and Characterisation

Development of Freeze-dried Reagents based Multiplex PCR Assay for the Detection of Common and Emerging Abortion-causing Pathogens

Bovine abortion is economically one of the most devastating problems faced by dairy farmers. Apart from non-infectious causes, several infectious pathogens are responsible for abortions, which sometimes manifests as abortion storms. Vaccine against several pathogens is available, in spite of that, abortions cause huge economic losses for the dairy sector. Timely and accurate identification of the etiological agent helps in adopting the mitigation steps to control the damage caused. In addition to the common abortion-causing pathogens such as Brucella abortus, Bovine herpesvirus-1 (BHV-1), bovine viral diarrhea virus (BVDV), several emerging viral causes are being investigated for their possible role in abortion, either exclusively or as co-infection. Molecular methods are widely accepted for the identification of the involved pathogens. However, these assays require individual screening against each pathogen which is time-consuming and uneconomical, hence the multiplex format of PCR assays has been adopted by several laboratories. Multiplexing in real-time PCR is a sensitive and reliable technique, but it requires trained manpower and sophisticated equipment which is largely unavailable in regional disease diagnostic laboratories in India. Hence, in this study, a user-friendly, ready-to-use, gel-based RT-PCR multiplex assay was developed for simultaneous detection of three common pathogens (B. abortus, BHV-1, and BVDV) and two emerging pathogens; bluetongue virus (BTV) as a cause of abortions in bovine and Schmallenberg virus (SBV). After the standardization of the assay, a panel of 211 samples was screened. A high degree of concordance was observed which indicates the developed multiplex PCR assay is reliable and has the potential for screening at regional diagnostic laboratories.

Comprehensive analysis of lncRNA expression profiles in cytopathic biotype BVDV-infected MDBK cells provides an insight into biological contexts of host-BVDV interactions

Bovine viral diarrhea virus (BVDV) is the causative agent of bovine viral diarrhea-mucosal disease, which significantly affects the production performance of cattle, causing serious economic losses to the cattle industries worldwide. Up to now, some mechanisms involved in host–BVDV interaction are still not fully understood. The discovery of long non-coding RNAs (lncRNAs) has provided a new perspective on gene regulation in diverse biological contexts, particularly in viral infection and host immune responses. However, little is known about the profiles and functions of lncRNAs in host cells in response to BVDV infection. Here, we utilized Illumina sequencing to explore lncRNAs profiles in cytopathic (CP) biotype BVDV-infected MDBK cells to further reveal the potential roles of lncRNAs in BVDV infection and host–BVDV interaction with integrated analysis of lncRNAs and mRNA expression profiles. A total of 1747 significantly differentially expressed genes, DEGs (156 lncRNAs and 1591 mRNAs) were obtained via RNA-seq in BVDV-infected MDBK cells compared to mock-infected cells. Next, these DE lncRNAs and mRNAs were subjected to construct lncRNAs-mRNAs co-expression network followed by the prediction of potential functions of the DE lncRNAs. Co-expression network analysis elucidated that DE lncRNAs were significant enrichment in NOD-like receptor, TNF, NF-ĸB, ErbB, Ras, apoptosis, and fatty acid biosynthesis pathways, indicating that DE lncRNAs play important roles in host–BVDV interactions. Our data give an overview of changes in transcriptome and potential roles of lncRNAs, providing molecular biology basis for further exploring the mechanisms of host–BVDV interaction.

Bovine viral diarrhoea virus loses quasispecies diversity rapidly in culture

Bovine viral diarrhoea (BVD) is an important disease of cattle, with significant impacts on animal health and welfare. The wide host range of the causative pestiviruses may lead to formation of virus reservoirs in other ruminant or wildlife species, presenting a concern for the long-term success of BVD eradication campaigns. It is likely that the quasispecies nature of these RNA viruses contributes to their interspecies transmission by providing genetic plasticity. Understanding the spectrum of sequence variants present in persistently infected (PI) animals is, therefore, essential for studies of virus transmission. To analyse quasispecies diversity without amplification bias, we extracted viral RNA from the serum of a PI cow, and from cell culture fluid after three passages of the same virus in culture, to produce cDNA without amplification. Sequencing of this material using Illumina 250 bp paired-read technology produced full-length virus consensus sequences from both sources and demonstrated the quasispecies diversity of this pestivirus A genotype 1a field strain within serum and after culture. We report the distribution and diversity of over 800 SNPs and provide evidence for a loss of diversity after only three passages in cell culture, implying that cultured viruses cannot be used to understand quasispecies diversity and may not provide reliable molecular markers for source tracing or transmission studies. Additionally, both serum and cultured viruses could be sequenced as a set of 25 overlapping PCR amplicons that demonstrated the same consensus sequences and the presence of many of the same quasispecies variants. The observation that aspects of the quasispecies structure revealed by massively parallel sequencing are also detected after PCR and Sanger sequencing suggests that this approach may be useful for small or difficult to analyse samples.