Bovine Viral Diarrhea Research Articles

Development and Evaluation of Recombinant NS3 Protein-based ELISA for the Detection of Bovine Viral Diarrhea Virus (BVDV) Antibodies

Background: Bovine Viral Diarrhea (BVD) is an important infectious disease that has a significant economic impact on dairy farms. Early detection of antibodies against BVD virus within herds can help reduce economic losses resulting from impaired animal health and reproductive performance. However, commercial ELISA tests tend to be expensive and unaffordable for smallholder farmers in Thailand. This study aims to develop an in- house indirect ELISA for the detection of antibodies to BVD. Methods: Gene synthesis and codon optimization were performed prior to protein expression. The prepared recombinant NS3 protein was confirmed through western blot analysis. Assay validation involved a comparison with an indirect commercial ELISA using a set of field serum samples (n=497) as references to evaluate its diagnostic accuracy. Measurements for test agreement and assay repeatability were calculated to assess performance. Result: The area under the receiver operating characteristic (ROC) curve was 0.86, indicating good discrimination between BVDV-positive and negative animals. The kappa coefficient, with an identified optimal cut-off value, was 0.577, indicated moderate agreement between the two tests. Additionally, the assay exhibited acceptable repeatability, with coefficients of variations (CVs) of 8.8% and 15.1% for intra-assay and inter-assay variations, respectively. This developed ELISA demonstrates both discriminatory ability and repeatability, making it a valuable alternative tool for the serodiagnosis of BVDV infection, especially in low-resource settings.

Serosurvey and Associated Risk Factors for Bovine Viral Diarrhea Virus Infection in Dromedary Camels in Egypt

Bovine viral diarrhea (BVD) is a disease that affects ruminants globally, including camels, and causing significant financial losses. The epidemiology of BVD in camels in Egypt are not well understood. Thus, this study aimed to determine the prevalence of anti-BVD virus (BVDV) antibodies in camels and identify the potential variables associated with the infection. A total of 400 camel sera from three Egyptian governorates were examined using commercial ELISA kit. The total seroprevalence was 4.8% in examined camels and the BVDV seropositivity were more prevalent in camels from Giza governorate. The highest seropositivity was found in aged camels more than 8 years (OR = 8.62, 95%CI: 1.03–71.87), camels from herd size less than 30 (OR = 4.20, 95%CI: 0.89–19.78), previously aborted animals (OR = 5.98, 95%CI: 2.12–16.92), and in animals kept in contact with sheep or goats (OR = 7.48, 95%CI: 2.56–21.86). Consequently, the camels may be a significant source of BVD infection for other ruminant animals in the same herd due to their susceptibility to the viral infection.

Screening and selection of essential oils for an intranasal spray against bovine respiratory pathogens based on antimicrobial, antiviral, immunomodulatory, and antibiofilm activities.

The rise in antibiotic resistant pathogens associated with bovine respiratory disease (BRD) poses a serious challenge, particularly to the beef feedlot industry, as they currently depend on antibiotics to prevent BRD to mitigate the financial burden (approx. $1 billion annual loss) inflicted by BRD-associated high mortality and morbidity in feedlot cattle. Thus, there is an impetus need for the development of antimicrobial alternative strategies against BRD. This study aimed to screen and select candidate essential oils (EOs) for the development of an intranasal EO spray that can inhibit BRD pathogens and promote microbiota-mediated respiratory health. The effects of selected EOs (ajowan, cinnamon leaf, citronella, grapefruit, fennel, and thyme) on a bovine nasopharyngeal microbiota culture were evaluated using 16S rRNA gene sequencing. The microbiota culture was enriched by incubating nasopharyngeal swabs obtained from finishing beef heifers in brain heart infusion broth with and without EOs (0.025%, v/v). These EOs were then also evaluated for their immunomodulatory effects on bovine turbinate (BT) cells by analyzing the concentrations of 15 cytokines and chemokines in cell culture after 24 h incubation. The crystal violet assay was done to assess the antibiofilm activity of EOs against Escherichia coli UMN026 strain. Finally, 15 EOs were screened for their antiviral activity against the bovine viral diarrhea virus 1 (BVDV-1) using BT cells and a fluorescence-based method. Ajowan, fennel, and thyme resulted in a moderate reduction of overall nasopharyngeal microbiota growth with significant alterations of both alpha and beta diversity, and the relative abundance of predominant bacterial families (e.g., increasing Enterobacteriaceae and decreasing Moraxellaceae) compared to the control (p < 0.05). Co-incubation of BT cells with selected EOs resulted in minimal alterations in cytokine and chemokine levels (p > 0.05). Ajowan, thyme, fennel, and cinnamon leaf exhibited antibiofilm activity at concentrations of 0.025 and 0.05%. Reduction of BVDV-1 replication in BT cells was observed with thyme (strong), and ajowan and citronella (moderate) at 0.0125% concentration. Accordingly, ajowan, thyme, fennel, cinnamon leaf, and citronella EOs were selected for further development as an intranasal EO spray to prevent and control of BRD pathogens in feedlot cattle.

Efficacy of H2O2 inactivated bovine virus diarrhoea virus (BVDV) type 1 vaccine in mice

BackgroundBovine viral diarrhea (BVD) is an acute febrile infectious disease caused by the bovine viral diarrhea virus (BVDV), which has brought huge economic losses to the world's cattle industry. At present, commercial inactivated BVDV vaccines may cause some adverse reactions during use. This study aims to develop a safer and more efficient inactivated BVDV vaccine.MethodsHere, we described the generation and preclinical efficacy of a hydrogen peroxide (H2O2) inactivated BVDV type 1 vaccine in mice, and administered it separately with commercial vaccine (formaldehyde inactivated) in mice to study its efficacy.ResultsThe BVDV type 1 IgG, IFN- γ, IL-4 and neutralizing antibody in the serum of the H2O2 inactivated vaccine group can be maintained in mice for 70 days. The IgG level reached its maximum value of 0.67 on the 42nd day, significantly higher than the commercial formaldehyde inactivated BVDV type 1 vaccine. IFN- γ and IL-4 reached their maximum values on the 28th day after immunization, at 123.16 pg/ml and 143.80 pg/ml, respectively, slightly higher than commercial vaccines, but the effect was not significant. At the same time the BVDV—1 neutralizing antibody titer reached a maximum of 12 Nu on the 42nd day post vaccination.ConclusionsThe H2O2 inactivated BVDV vaccine has good safety and immunogenicity, which provides a potential solution for the further development of an efficient and safe BVDV vaccine.

Monitoring swine virus transmission in embryos derived from commercial abattoir oocytes.

Pigs are pivotal in agriculture and biomedical research and hold promise for xenotransplantation. Specific-pathogen-free (SPF) herds are essential for commercial swine production and xenotransplantation research facilities. Commercial herds aim to safeguard animal health, welfare, and productivity, and research facilities require SPF status to protect immunocompromised patients. Somatic cell nuclear transfer (SCNT) embryos are the norm for producing cloned and genetically edited animals. Oocytes for embryo reconstruction are most conveniently sourced from commercial abattoirs with unclear disease statuses. However, research on viral clearance from donor oocytes during embryo reconstruction remains limited. SCNT has previously been shown to reduce the transmission of Porcine reproductive and respiratory syndrome virus, Bovine viral diarrhea virus, Porcine Circovirus type 2, and Porcine parvovirus. Still, it is lacking for other pathogens, including endogenous viruses. This project contains two preliminary studies investigating the polymerase chain reaction (PCR) assay detection of common swine viruses through the phases of producing parthenogenic and SCNT embryos. Exogenous pathogens detected in oocyte donor tissue or the oocyte maturation media were not detected in the produced embryos. Porcine endogenous retrovirus type C (PERVC) was not removed by parthenogenic embryo activation and was detected in 1 of the 2 tested SCNT embryos reconstructed using a PERVC-negative cell line. SCNT and parthenogenic embryo construction similarly reduced exogenous virus detection. SCNT embryo construction helped reduce endogenous virus detection. This project demonstrates the importance of screening embryos for endogenous viruses and shows the usefulness of parthenogenic embryos in future exogenous virus clearance studies.

The gut microbiota contributes to the infection of bovine viral diarrhea virus in mice.

Bovine viral diarrhea virus (BVDV) is prevalent worldwide and causes significant economic losses. Gut microbiota is a large microbial community and has a variety of biological functions. However, whether there is a correlation between gut microbiota and BVDV infection and what kind of relation between them have not been reported. Here, we found that gut microbiota composition changed in normal mice after infecting with BVDV, but mainly the low abundance microbe was affected. Interestingly, BVDV infection significantly reduced the diversity of gut microbiota and changed its composition in gut microbiota-dysbiosis mice. Furthermore, compared with normal mice of BVDV infection, there were more viral loads in the duodenum, jejunum, spleen, and liver of the gut microbiota-dysbiosis mice. However, feces microbiota transplantation (FMT) reversed these effects. The data above indicated that the dysbiosis of gut microbiota was a key factor in the high infection rate of BVDV. It is found that the IFN-I signal was involved by investigating the underlying mechanisms. The inhibition of the proliferation and increase in the apoptosis of peripheral blood lymphocytes (PBL) were also observed. However, FMT treatment reversed these changes by regulating PI3K/Akt, ERK, and Caspase-9/Caspase-3 pathways. Furthermore, the involvement of butyrate in the pathogenesis of BVDV was also further confirmed. Our results showed for the first time that gut microbiota acts as a key endogenous defense mechanism against BVDV infection; moreover, targeting regulation of gut microbiota structure and abundance may serve as a new strategy to prevent and control the disease.IMPORTANCEWhether the high infection rate of BVDV is related to gut microbiota has not been reported. In addition, most studies on BVDV focus on in vitro experiments, which limits the study of its prevention and control strategy and its pathogenic mechanism. In this study, we successfully confirmed the causal relationship between gut microbiota and BVDV infection as well as the potential molecular mechanism based on a mouse model of BVDV infection and a mouse model of gut microbiota dysbiosis. Meanwhile, a mouse model which is more susceptible to BVDV provided in this study lays an important foundation for further research on prevention and control strategy of BVDV and its pathogenesis. In addition, the antiviral effect of butyrate, the metabolites of butyrate-producing bacteria, has been further revealed. Overall, our findings provide a promising prevention and control strategy to treat this infectious disease which is distributed worldwide.

Serosurvey and associated risk factors for bovine viral diarrhea virus infection in cattle in Egypt.

Bovine viral diarrhea virus (BVDV), is widely spread, poses a considerable risk of infection in the majority of dairy farms, causing respiratory, gastrointestinal, and reproductive problems. The aim of this study was to determine the seroprevalence and the risk variables associated with the seroprevalence of BVDV infection in cattle in four Egyptian governorates. A total of 680 blood samples were collected from cattle and examined for the presence of antibodies against BVDV using indirect ELISA (iELISA). Reproductive and management factors were considered, and epidemiological surveys were conducted. The total seroprevalence of BVDV in cattle was 18.24% (124/680) and it was significantly higher in females 19.66% (116/590), cattle older than 8years 22.14% (62/280), dairy animals 22.65% (94/514), introduction of new animals to herd 21.39% (89/416), breeding with artificial insemination 28.46% (74/260), animals with history of abortion 28.76% (49/357), or during lactation stage 23% (89/387). The present findings suggest that BVD is prevalent in Egyptian dairy cattle and has an impact on farm productivity and production. Therefore, older, lactating, and aborted animals should also be identified for the disease, pose a risk of infection, and be handled appropriately.

Coding-complete genomic sequence of bovine viral diarrhea virus isolated from a calf in Taiwan.

The coding-complete genomic sequence of a Taiwanese bovine viral diarrhea virus (BVDV) was sequenced. Phylogenetic analysis suggested that the Taiwanese isolate belonged to the 1b clade. This study will advance the understanding of BVDV genotypes in Southeast Asia and promote future studies on BVDV epidemiology in Taiwan.

Mitochondria-mediated ferroptosis contributes to the inflammatory responses of bovine viral diarrhea virus (BVDV) in vitro.

Bovine viral diarrhea virus (BVDV) belongs to the family Flaviviridae and includes two biotypes in cell culture: cytopathic (CP) or non-cytopathic (NCP) effects. Ferroptosis is a non-apoptotic form of programmed cell death that contributes to inflammatory diseases. However, whether BVDV induces ferroptosis and the role of ferroptosis in viral infection remain unclear. Here, we provide evidence that both CP and NCP BVDV can induce ferroptosis in Madin-Darby bovine kidney cells at similar rate. Mechanistically, biotypes of BVDV infection downregulate cytoplasmic and mitochondrial GPX4 via Nrf2-GPX4 pathway, thereby resulting in lethal lipid peroxidation and promoting ferroptosis. In parallel, BVDV can degrade ferritin heavy chain and mitochondrial ferritin via NCOA4-mediated ferritinophagy to promote the accumulation of Fe2+ and initiate ferroptosis. Importantly, CP BVDV-induced ferroptosis is tightly associated with serious damage of mitochondria and hyperactivation of inflammatory responses. In contrast, mild or unapparent damage of mitochondria and slight inflammatory responses were detected in NCP BVDV-infected cells. More importantly, different mitophagy pathways in response to mitochondria damage by both biotypes of BVDV are involved in inflammatory responses. Overall, this study is the first to show that mitochondria may play key roles in mediating ferroptosis and inflammatory responses induced by biotypes of BVDV in vitro.IMPORTANCEBovine viral diarrhea virus (BVDV) threatens a wide range of domestic and wild cattle population worldwide. BVDV causes great economic loss in cattle industry through its immunosuppression and persistent infection. Despite extensive research, the mechanism underlying the pathogenesis of BVDV remains elusive. Our data provide the first direct evidence that mitochondria-mediated ferroptosis and mitophagy are involved in inflammatory responses in both biotypes of BVDV-infected cells. Importantly, we demonstrate that the different degrees of injury of mitochondria and inflammatory responses may attribute to different mitophagy pathways induced by biotypes of BVDV. Overall, our findings uncover the interaction between BVDV infection and mitochondria-mediated ferroptosis, which shed novel light on the physiological impacts of ferroptosis on the pathogenesis of BVDV infection, and provide a promising therapeutic strategy to treat this important infectious disease with a worldwide distribution.

Bovine viral diarrhoea viruses from New Zealand belong predominantly to the BVDV-1a genotype

Aim To determine which genotypes of bovine viral diarrhoea virus (BVDV) circulate among cattle in New Zealand. Methods Samples comprised BVDV-1-positive sera sourced from submissions to veterinary diagnostic laboratories in 2019 (n = 25), 2020 (n = 59) and 2022 (n = 74) from both beef and dairy herds, as well as archival BVDV-1 isolates (n = 5). Fragments of the 5′ untranslated region (5′ UTR) and glycoprotein E2 coding sequence of the BVDV genome were amplified and sequenced. The sequences were aligned to each other and to international BVDV-1 sequences to determine their similarities and phylogenetic relationships. The 5′ UTR sequences were also used to create genetic haplotype networks to determine if they were correlated with selected traits (location, type of farm, and year of collection). Results The 5′ UTR sequences from New Zealand BVDV were closely related to each other, with pairwise identities between 89% and 100%. All clustered together and were designated as BVDV-1a (n = 144) or BVDV-1c (n = 5). There was no evidence of a correlation between the 5′ UTR sequence and the geographical origin within the country, year of collection or the type of farm. Partial E2 sequences from New Zealand BVDV (n = 76) showed 74–100% identity to each other and clustered in two main groups. The subtype assignment based on the E2 sequence was the same as based on the 5′ UTR analysis. This is the first comprehensive analysis of genomic variability of contemporary New Zealand BVDV based on the analysis of the non-coding (5′ UTR) and coding (E2) sequences. Conclusions and clinical relevance Knowledge of the diversity of the viruses circulating in the country is a prerequisite for the development of effective control strategies, including a selection of suitable vaccines. The data presented suggest that New Zealand BVDV are relatively homogeneous, which should facilitate eradication efforts including selection or development of the most suitable vaccines.

Comparison of bovine viral diarrhea virus detection methods: Results of an international proficiency trial

Bovine viral diarrhea virus (BVDV), one of the most important infectious cattle diseases globally, is being combated in multiple countries. The main source for virus transmission within herds and especially to unaffected cattle farms are life-long persistently infected (PI), immunotolerant animals. Therefore, the early identification of PI calves is a major pillar of disease control programs. In addition, rapid and reliable virus identification is necessary to confirm the causative agent in acute clinical cases. Here, we initiated an international interlaboratory proficiency trial in order to evaluate BVDV detection methods.Four ear notch samples and four sera were provided to the participating veterinary diagnostic laboratories (n = 40). Two of the ear notches and two sera contained BVDV and two ear notches and one serum were negative for pestiviruses. The remaining serum was positive for the ovine border disease virus (BDV). The sample panel was analyzed by an ERNS-based ELISA for antigen detection, diverse real-time RT-PCR (RT-qPCR) assays and/or virus isolation. Occasionally, additional typing of the virus strains was performed by sequencing or specific antibody staining of the obtained cell culture isolates. While the antigen ELISA allowed reliable BVDV diagnostics, infectious virus could be isolated only in just under half of the attempts (43.33%). RT-qPCR enabled the sensitive detection of pestiviruses, though an impact of the extraction method on the resulting quantification cycle values was observed. In general, subsequent typing of the detected virus strains is required to differentiate BVDV from BDV infections.In conclusion, for BVDV identification in clinical cases or in the context of disease control, RT-qPCR methods or ERNS antigen ELISAs should be preferentially used.

A multiplex real-time fluorescence-based quantitative PCR assay for calf diarrhea viruses.

Calf diarrhea is a significant condition that has a strong effect on the cattle industry, resulting in huge economic losses annually. Bovine torovirus (BToV), bovine enterovirus (BEV), bovine norovirus (BNoV), bovine coronavirus (BCoV), bovine rotavirus (BRV), and bovine viral diarrhea virus (BVDV) are key pathogens that have been implicated in calf diarrhea. Among these viruses, there remains limited research on BToV, BEV, and BNoV, with no available vaccines or drugs for their prevention and control. Although commercial vaccines exist for BCoV, BRV, and BVDV, the prevalence of these diseases remains high. To address this issue, we developed a multiplex real-time fluorescence quantitative PCR method for detecting BToV, BEV, BNoV, BCoV, BRV, and BVDV. This method can be used to effectively monitor the prevalence of these six viruses and serve as a reference for future prevention and control strategies. In this study, we specifically designed primers and probes for the BNoV Rdrp, BEV 5'UTR, BToV M, BCoV N, BRV NSP5, and BVDV 5'UTR genes. This method was determined to be efficient, stable, and sensitive. The lowest detectable levels of plasmids for BNoV, BEV, BToV, BRV, BCoV, and BVDV were 1.91 copies/μL, 96.0 copies/μL, 12.8 copies/μL, 16.4 copies/μL, 18.2 copies/μL, and 65.3 copies/μL, respectively. Moreover, the coefficients of variation for all six detection methods were < 3%; they also exhibited a strong linear relationship (R2 ≥ 0.98), and an amplification efficiency of 90%-110%. A total of 295 fecal and anal swabs were collected from calves with diarrhea in Guangdong, China. The positive rates for BToV, BEV, BNoV, BCoV, BR, and BVDV were determined to be 0.34% (1/295), 6.10% (18/295), 0.68% (2/295), 1.36% (4/295), 10.85% (32/295), and 2.03% (6/295), respectively. Notably, BEV and BRV exhibited the highest prevalence. Additionally, this study identified the occurrence of BToV and BNoV in Guangdong for the first time. In summary, this study successfully established an effective method for detecting several important bovine viruses; ultimately, this holds strong implications for the future development of the cattle industry.

"Fading out" - genomic epidemiology of the last persistently infected BVDV cattle in Germany.

Bovine viral diarrhea virus (BVDV) is one of the most important cattle pathogens worldwide, causing major economic losses and animal welfare issues. Disease eradication programs have been implemented in several countries, including Germany where an obligatory nationwide control program is in force since 2011. As molecular epidemiology has become an essential tool to understand the transmission dynamics and evolution of BVDV, 5' untranslated region (UTR) sequences are generated from viruses present in persistently infected animals since the beginning of the BVDV control program. Here, we report the results of the sequence-based subtyping of BVDV strains found from 2018 through 2022 in calves born in Germany. In 2018, 2019 and 2020, BVDV-1d and-1b were the dominant subtypes and cases were spread throughout the area that was not yet officially declared BVDV-free at that time. In addition, BVDV-1a, -1e, -1f and -1h could rarely be detected. From 2021 onwards, subtype 1d clearly took over the dominance, while the other subtypes could be gradually nearly eliminated from the cattle population. The eradication success not only results in a drastic reduction of cases, but also in a marked reduction of strain diversity. Interestingly, before vaccination has been banned in regions and farms with a disease-free status, two live-vaccine virus strains were repeatedly detected in ear tissue samples of newborn calves (n = 14) whose mothers were immunized during gestation. The field-virus sequences are an important basis for molecular tracing and identification of potential relationships between the last outbreaks in the final phase of the German BVDV eradication program, thereby supporting classic epidemiological investigations. Furthermore, the monitoring of the composition of virus subtypes in the cattle population helps to maintain effective diagnostic methods and control measures and is an early warning system for the introduction of new pestiviruses in the naïve cattle population.

The impact of bovine viral diarrhoea virus on fertility in cattle and the protective effect of vaccination

Bovine viral diarrhoea virus (BVDV) infection is associated with significant reproductive losses in cattle through the detrimental impact of both persistent and transient infection on breeding females and males. The pathology within the reproductive tract is well described, although the mechanisms that lead to reproductive failure have yet to be fully unravelled. Prolonged shedding of virus following acute infection of bulls in both the peri- and post-pubertal periods has been observed, although the significance of this in relation to reproductive failure and the spread of infection has yet to be fully explored for the UK situation. Infection and recovery lead to an immune state in the female that is protective against breeding failure and generation of persistently infected calves. Vaccination using either of the two vaccines licensed for the control of BVDV infection in breeding cattle in the UK has been shown to be protective against fetal infection. In the UK where regional and herd level eradication of BVDV is progressing against a background of endemic infection, vaccination would appear to offer stopgap mitigation against reinfection until such times as national eradication is achieved.

Herd‐Level Modeling of Bovine Viral Diarrhea Virus (BVDV) Transmission in Cattle Herds in Southern Chile: Linking Within and Between‐Herd Dynamics

Bovine viral diarrhea (BVD) represents a serious threat to the cattle sector in Chile, indicating the need for a regionally defined control program. Ex-ante evaluations of program options using simulation modeling have proven to be a successful approach in providing decision‐makers with relevant supporting insights in that respect. Given the complexity of bovine viral diarrhea virus (BVDV) infection dynamics, simulation of BVD spread in a metapopulation requires detailed consideration of both within and between herd transmission dynamics. The aims of the study are (i) to investigate the dynamics of BVDV transmission in cattle herds in southern Chile by linking a within‐herd transmission model (WHM) that accounts for the BVDV’s unique characteristics with a between‐herd model (BHM) that meets the demands for further regional control strategy evaluation; (ii) to suggest and discuss criteria for evaluation of the model approach and plausibility for later research and for support decision‐making. This resulted in bringing forth a modeling rationale for complex disease spread simulation in metapopulations. BHM simulations under this approach show outcomes that agree with BVDV’s known situation in Chile; dairy herds prevalence at endemic equilibrium reaches and maintains 75%, which agrees with estimations of BVDV active infection in dairy herds in southern Chile (77%). For the entire herd population, the infection always reaches endemic levels with a large proportion of infected herds (median = 60%), where herd prevalence was higher in the dairy herd class than in the remaining categories. Transmission probability variation affects the new infections picked, prevalence at endemic levels, and the velocity in which the infection spreads between herds. The fact that the presented approach was able to model a complex infection dynamic such BVDV, with sufficient confidence, provides evidence that this approach can be used to explore mitigation strategies to control BVDV in southern Chilean herds.

Práticas de biosseguridade associadas com infecção do vírus da diarreia viral bovina em rebanhos leiteiros no Brasil

ABSTRACT: This study determined the association between biosecurity practices and the status of bovine viral diarrhea virus (BVDV) in dairy production systems. Approximately 280 herds were screened for BVDV virus detection. Following the screening, 68 herds were selected to identify individual BVDV PI animals using an ear notch biopsy and ELISA-antigen. All offspring of the last generation were tested, and the maternal lineage of positive cases was examined. A questionnaire on BVDV biological risk assessment was completed. A multiple correspondence analysis (MCA) was conducted to determine the association between herds with or without BVDV circulation and biosecurity practices. The MCA revealed that farms with virus circulation lacked knowledge about the disease and wrongly perceived their herds as protected, while farms without virus circulation were aware of the disease but considered their herds unprotected. Vaccination practices differed between positive and negative herds, with positive herds using vaccines only for reproductive diseases and negative herds vaccinating for respiratory and reproductive issues. Biosecurity practices such as frequent visitation, contact between animals of different ages, and annual introduction of new animals were linked to viral circulation, while virus-free herds implemented measures like controlled visitation, no contact between different age groups, and quarantine. Lastly, herds with virus circulation acquired pregnant females without prior testing. This study emphasized the crucial role of biosecurity practices in controlling BVDV in dairy herds. It highlighted the sharper risk perception and better application of biosecurity practices in negative herds compared to BVDV-positive herds.

Antiviral activity of bovine type III interferon against bovine viral diarrhea virus is greatly reduced in bovine turbinate cells due to limited expression of IFN lambda receptor 1 (IL-28Rα).

The antiviral activity of recombinant bovine interferon lambda 3 (bovIFN-λ3) against bovine viral diarrhea virus (BVDV) has been demonstrated in vitro in Madin-Darby bovine kidney cells (MDBK) and in vivo in cattle. However, anti-BVDV activity of bovIFN-λ3 has not been studied in bovine respiratory tract epithelial cells, supposedly a primary target of BVDV infection when entering the host by the oronasal route. Here we investigated the anti-BVDV activity of bovIFN-λ3 in bovine turbinate-derived primary epithelial cells (BTu) using BVDV infection and immunoperoxidase staining, TCID50, RT-qPCR, DNA and transcriptome sequencing, and transfection with plasmids containing the two subunits, IL-28Rα and IL-10Rβ that constitute the bovIFN-λ3 receptor. Our immunoperoxidase staining, RT-qPCR, and TCID50 results show that while BVDV was successfully cleared in MDBK cells treated with bovIFN-λ3 and bovIFN-α, only the latter, bovIFN-α, cleared BVDV in BTu cells. Preincubation of MDBK cells with bovIFN-λ3 before BVDV infection was needed to induce optimal antiviral state. Both cell types displayed intact type I and III IFN signaling pathways and expressed similar levels of IL-10Rβ subunit of the type III IFN receptor. Sequencing of PCR amplicon of the IL-28Rα subunit revealed intact transmembrane domain and lack of single nucleotide polymorphisms (SNPs) in BTu cells. However, RT-qPCR and transcriptomic analyses showed a lower expression of IL-28Rα transcripts in BTu cells as compared to MDBK cells. Interestingly, transfection of BTu cells with a plasmid encoding IL-28Rα subunit, but not IL-10Rβ subunit, established the bovIFN-λ3 sensitivity showing similar anti-BVDV activity to the response in MDBK cells. Our results demonstrate that the sensitivity of cells to bovIFN-λ3 depends not only on the quality but also of the quantity of the IL-28Rα subunit of the heterodimeric receptor. A reduction in IL-28Rα transcript expression was detected in BTu as compared to MDBK cells, despite the absence of spliced variants or SNPs. The establishment of bovIFN-λ3 induced anti-BVDV activity in BTu cells transfected with an IL-28Rα plasmid suggests that the level of expression of this receptor subunit is crucial for the specific antiviral activity of type III IFN in these cells.

Problems of cattle health improvement and protection of population against viral diarrhoea under current conditions of animal husbandry

The article presents the dynamics of the prevalence of bovine viral diarrhoea virus (BVDV) in livestock enterprises of the Ural region in the period 2018-2023. Retrospective and operational analysis of monitoring data showed that the epizootic situation was consistently tense. The share of unfavourable livestock enterprises ranged from 18.2% to 33.3%. The cumulative infection rate in different age groups of cattle ranged from 2.3% to 23.3%. Clinical symptoms of acute course of BVDV-infection in examined cattle were registered in 10.9% of cases; persistent form of BVDV-infection - in 16.5% of cases; subclinical course of BVDV-infection and latent form - in 73.6% of cases. Phylogenetic analysis of BVDV isolates obtained from animal biosamples showed that 81.8% of isolates belong to the Cp-biotype of BVDV, 18.2% of isolates - to the Ncpbiotype of BVDV. It has been established that the intensity of pathogen eradication decreases in livestock enterprises when the regulations of specific prophylaxis are violated, as evidenced by the increase in the number of animals carrying BVDV by 4%; calves with diseases caused by BVDV infection - by 2.5%; cows and heifers with reproductive losses - by 5.7%.

First evaluation of the impact of a targeted subunit vaccine against bovine viral diarrhea virus in feedlot cattle.

Bovine respiratory disease (BRD) is a serious health and economic problem in the beef industry, which is often associated with transportation and caused by different pathogens. In this study, we evaluated the effect of a novel subunit targeted vaccine against bovine viral diarrhea virus (BVDV) in feedlot cattle, a major viral agent of BRD. The core of this novel vaccine is the fusion of the BVDV structural glycoprotein, E2, to a single-chain antibody, APCH, together termed, APCH-E2. The APCH antibody targets the E2 antigen to the major histocompatibility type II molecule (MHC-II) present in antigen-presenting cells. To evaluate the vaccine, 2,992 animals were randomly allocated into two groups, control group (N = 1,491) and treatment group (N = 1,501). Animals of both groups received the routine sanitary plan: two doses of clostridial, respiratory, and rabies vaccines. Animals within the treatment group also received two doses of a targeted subunit vaccine against BVDV. Serum samples were taken on the day of the first inoculation (T0) and 90 d later (T90). Viral circulation was monitored using an anti-P80 ELISA (virus-specific) and immune response was evaluated by anti-E2 ELISA (detects virus and vaccine immune responses). Only animals treated for respiratory disease were considered positive cases of BRD. Results demonstrate that the control group had significantly more animals treated for BRD cases compared to the treatment group (5.9% vs. 3.7%, P = 0.02). The control group had a greater number of animals positive for anti-P80 antibodies and significantly fewer animals positive for anti-E2 antibodies compared to the treatment group (69% vs. 61% and 71% vs. 99%, respectively, P = 0.003), consistent with natural viral circulation within this group. The treatment group, conversely, had fewer animals positive for anti-P80 antibodies and a greater number of animals positive for anti-E2 antibodies, consistent with a robust vaccine-induced antibody response and a reduction of the BVDV circulation within this group. The data indicate the new subunit targeted vaccine induced greater anti-E2 antibodies and reduced the amount of BVD virus circulation within the treatment group leading to a fewer number of animals needing to be treated for BRD.

Combining a lateral flow immunoassay with triplex loop-mediated isothermal amplification for the concurrent identification of three bovine diarrhea syndrome viruses.

Numerous viruses, such as the bovine rotavirus (BRV), the bovine parvovirus (BPV), and the bovine viral diarrhea virus (BVDV), can cause bovine viral diarrhea syndrome. The global livestock industry has been subjected to significant consequences due to this condition. This results in considerable losses and hinders the production of crucial resources such as meat and milk, which are indispensable for sustaining the world's population. It is crucial to develop a quick and precise way of simultaneously detecting BVDV, BRV, and BPV, as they often occur together in mixed infections. A triplex loop-mediated isothermal amplification-lateral flow dipstick (LAMP-LFD) assay that can concurrently detect all three viruses was introduced in this study. The amplification process involved 30 minutes of incubation at 65 °C. The limits of detection (LODs) for BVDV, BRV, and BPV were 2.62 × 101 copies per μL, 2.43 × 101 copies per μL, and 2.50 × 101 copies per μL, respectively. The triplex LAMP-LFD assay was further evaluated in 156 anal swab samples, and the results were in agreement with the results of fluorescence quantitative PCR (qPCR) in more than 99% of the cattle. This assay is expected for the quick identification of triplex viruses in the field because it has high sensitivity and specificity and doesn't depend on laboratory equipment or conditions.