A systematic review of financial and economic assessments of bovine viral diarrhea virus (BVDV) prevention and mitigation activities worldwide

Exploring viral diversity and metagenomics in livestock: insights into disease emergence and spillover risks in cattle

Cattle have a significant impact on human societies in terms of both economics and health. Viral infections pose a relevant problem as they directly or indirectly disrupt the balance within cattle populations. This has negative consequences at the economic level for producers and territories, and also jeopardizes human health through the transmission of zoonotic diseases that can escalate into outbreaks or pandemics. To establish prevention strategies and control measures at various levels (animal, farm, region, or global), it is crucial to identify the viral agents present in animals. Various techniques, including virus isolation, serological tests, and molecular techniques like PCR, are typically employed for this purpose. However, these techniques have two major drawbacks: they are ineffective for non-culturable viruses, and they only detect a small fraction of the viruses present. In contrast, metagenomics offers a promising approach by providing a comprehensive and unbiased analysis for detecting all viruses in a given sample. It has the potential to identify rare or novel infectious agents promptly and establish a baseline of healthy animals. Nevertheless, the routine application of viral metagenomics for epidemiological surveillance and diagnostics faces challenges related to socioeconomic variables, such as resource availability and space dedicated to metagenomics, as well as the lack of standardized protocols and resulting heterogeneity in presenting results. This review aims to provide an overview of the current knowledge and prospects for using viral metagenomics to detect and identify viruses in cattle raised for livestock, while discussing the epidemiological and clinical implications.

Matrine and icariin can inhibit bovine viral diarrhoea virus replication by promoting type I interferon response in vitro

Introduction

Bovine viral diarrhoea virus (BVDV) can cause diarrhoea (BVD) in an animal herd, leading to heavy economic losses. There are limited drugs available for treating and controlling BVD. This research aims to investigate the antiviral and immunoregulatory effects of two traditional Chinese herb extracts against BVDV infection. The extracts are matrine and icariin, which have been proved to have immunostimulant and antiviral effects.

Material and Methods

A cell counting kit-8 assay was used to analyse the toxicity of matrine and icariin to Madin-Darby bovine kidney (MDBK) cells. The model of MDBK cells infected with BVDV was utilised to uncover the antiviral mechanism of matrine and icariin, which along with their immunoregulatory ability was evaluated by quantitative reverse-transcription PCR and ELISA.

Results

The results showed that matrine and icariin can significantly inhibit the gene expression level of the BVDV 5' untranslated region through various pathways. Both matrine and icariin can statistically upregulate the gene expression level of interferon alpha, interferon beta (IFN-β), toll-like receptor 3, retinoic acid-inducible gene I and interferon regulatory factor 3, and raise the concentration of IFN-β after BVDV infection.

Conclusion

This study proves that both matrine and icariin have inhibitory effects on BVDV replication by activating IFN production and the IFN signalling pathway. The finding is promising and should open up the possibility of larger-scale in vitro research followed by in vivo experiments evaluating matrine and icariin as therapeutic agents in BVD cases.

[Persistent form of bovine viral diarrhea]

The review provides an analysis of literature data on the persistent form of Bovine Viral diarrhea/Mucosal disease (BVD) and is focused on virus and host factors, including those related to immune response, that contribute the persistence of the virus. BVD is a cattle disease widespread throughout the world that causes significant economic damage to dairy and beef cattle. The disease is characterized by a variety of clinical signs, including damage to the digestive and respiratory organs, abortions, stillbirths and other failures of reproductive functions.

Seroprevalence of five diarrhea-related pathogens in bovine herds of scattered households in Inner Mongolia, China between 2019 and 2022

Bovine diarrhea is a multi-factorial disease and remains one of the biggest health problems in animal husbandry. The endemic trends of the main pathogens responsible for bovine diarrhea in Inner Mongolia have not been analyzed systematically before. Therefore, the purpose of this study was to estimate the prevalence of bovine diarrhea pathogens found in the scattered households of Inner Mongolia in China. Additionally, we assessed for differences in the prevalence of infection based on age and region, as well as determined local prevalence rates and the rates of mixed infections. Using a two-stage random sampling strategy, 3,050 serum samples were collected from 72 bovine herds in 11 leagues and cities in Inner Mongolia, and the positive rates of BVDV, BRV, BCoV, K99, and Mycobacterium paratuberculosis (M. paratuberculosis) antibodies in the samples were detected by ELISA to determine the epidemic trends and epidemic differences of the five pathogens in Inner Mongolia. The positive rates of antibodies based on serum samples were: BVDV, 18.79% (95% CI [17.44-20.22]); BRV, 12.39% (95% CI [11.27-13.61]); BCoV, 12.82% (95% CI [11.68-14.05]); K99, 13.80% (95% CI [12.62-15.07]); and M. paratuberculosis, 10.79% (95% CI [9.74-11.94]). The prevalence rates of BRV, BCoV and K99 at 0-2 months were significantly different from that at 2-6 months, 6-18 months and adult cattle (P < 0.05). The prevalence of BVDV and M. paratuberculosis was the highest in adult cattle, which was significantly different from that in other age groups (P < 0.05). Furthermore, obvious regional epidemiological differences among the five diseases were observed. There was a mixed infection of BRV+BCoV in each age stage, the highest mixed infection being BVDV+BRV+K99 at 0-2 months of age. Our results showed that the cattle of scattered households in the Inner Mongolia of China were endemicly infected with several important cattle pathogens. Most of the pathogens studied occurred between 0-2 months of age and were mixed infections, which greatly influences the health of the cattle and leads to economic loss. These findings are of practical significance for the future prevention and control of bovine diarrhea in the Inner Mongolia or other regions of China.

Integrative Transcriptomics and Proteomics Analysis Reveals Immune Response Process in Bovine Viral Diarrhea Virus-1-Infected Peripheral Blood Mononuclear Cells

Bovine viral diarrhea virus (BVDV) causes bovine viral diarrhea-mucosal disease, inflicting substantial economic losses upon the global cattle industry. Peripheral blood mononuclear cells (PBMCs) are the central hub for immune responses during host-virus infection and have been recognized as crucial targets for BVDV infection. In order to elucidate the dynamics of host-BVDV-1 interaction, this study harnessed RNA-seq and iTRAQ methods to acquire an extensive dataset of transcriptomics and proteomics data from samples of BVDV-1-infected PBMCs at the 12-h post-infection mark. When compared to mock-infected PBMCs, we identified 344 differentially expressed genes (DEGs: a total of 234 genes with downregulated expression and 110 genes with upregulated expression) and 446 differentially expressed proteins (DEPs: a total of 224 proteins with downregulated expression and 222 proteins with upregulated expression). Selected DEGs and DEPs were validated through quantitative reverse transcriptase-polymerase chain reaction and parallel reaction monitoring. Gene ontology annotation and KEGG enrichment analysis underscored the significant enrichment of DEGs and DEPs in various immunity-related signaling pathways, including antigen processing and presentation, complement and coagulation cascades, cytokine-cytokine receptor interaction, and the NOD-like receptor signaling pathway, among others. Further analysis unveiled that those DEGs and DEPs with downregulated expression were predominantly associated with pathways such as complement and coagulation cascades, the interleukin-17 signaling pathway, cytokine-cytokine receptor interaction, the PI3K-Akt signaling pathway, the tumor necrosis factor signaling pathway, and the NOD-like receptor signaling pathway. Conversely, upregulated DEGs and DEPs were chiefly linked to metabolic pathways, oxidative phosphorylation, complement and coagulation cascades, and the RIG-I-like receptor signaling pathway. These altered genes and proteins shed light on the intense host-virus conflict within the immune realm. Our transcriptomics and proteomics data constitute a significant foundation for delving further into the interaction mechanism between BVDV and its host.

First report of bovine viral diarrhea virus subgenotypes 1d and 1e in southern Chile

Bovine viral diarrhea virus (BVDV) affects cattle worldwide causing severe productive and economic loss. In this study, we investigated the subgenotypes of BVDV circulating in cattle samples from the Aysén region, an active cattle breeding area located in southern Chile. Partial amplification of the 5' untranslated region (UTR) was performed by polymerase chain reaction (PCR), and twelve samples were analyzed by Sanger sequencing and phylogenetic analysis. Eight samples were identified as belonging to Pestivirus bovis subgenotype 1e, three to 1-b, and one to 1-d. The phylogenetic analyses performed revealed a marked distance between these now-identified strains and those previously reported in the country. These findings support the need to continually expand the analysis of the variability of the viral phylogeny for the currently circulating BVDV strains and to update the vaccines recommended for this livestock area and surrounding areas.

Diagnosis of Ruminant Viral Diseases with Loop-Mediated Isothermal Amplification

Infectious diseases in livestock industry are major problems for animal health, food safety, and the economy. Zoonotic diseases from farm animals are significant threat to human population as well. These are notifiable diseases listed by the World Organization for Animal Health (OIE). Rapid diagnostic methods can help keep infectious diseases under control in herds. Loop-mediated isothermal amplification (LAMP) is a simple and rapid nucleic acid amplification method that is studied widely for detection of many infectious diseases in the field. LAMP allows biosensing of target DNA or RNA under isothermal conditions with high specificity in a short period of time. An untrained user can analyze results based on color change or turbidity. Here we review LAMP assays to diagnose OIE notifiable ruminant viral diseases in literature highlighting properties of LAMP method considering what is expected from an efficient, field usable diagnostic test.

HoBi-like Pestivirus Is Highly Prevalent in Cattle Herds in the Amazon Region (Northern Brazil)

Pestiviruses are globally distributed and cause substantial economic losses to the cattle industry. In Brazil, the country with the world's largest cattle population, pestivirus infections are well described in some regions, such as in the south, where a high frequency of BVDV-2 is described and contrasts with the high prevalence of HoBi-like pestivirus (HoBiPeV) in the northeast. However, there is a lack of information about pestiviruses in the Amazon Region, in northern Brazil, with a cattle population estimated at 55.7 million head, which has a significant impact on the international livestock market. Therefore, this study investigated the seroprevalence and genetic variability of ruminant pestiviruses in 944 bovine serum samples from four states in northern Brazil: Pará (PA), Amapá (AP), Roraima (RR), and Amazonas (AM). Our results showed that 45.4% of the samples were seropositive (19.8% for BVDV-1, 14.1% for BVDV-2, and 20.9% for HoBiPeV). All samples were tested by RT-qPCR, and three were positive and classified as HoBiPeV in a phylogenetic analysis. These serological and molecular results contrast with those from other regions of the world, suggesting that the northern Brazilian states have a high prevalence of all bovine pestiviruses including HoBiPeV.

Different Types of Vaccines against Pestiviral Infections: "Barriers" for "Pestis"

The genus Pestivirus of the family Flaviviridae mainly comprises classical swine fever virus (CSFV), bovine viral diarrhea virus 1 (BVDV-1), BVDV-2, border disease virus (BDV), and multiple new pestivirus species such as atypical porcine pestivirus (APPV), giraffe pestivirus, and antelope pestivirus. Pestiviruses cause infectious diseases, resulting in tremendous economic losses to animal husbandry. Different types of pestivirus vaccines have been developed to control and prevent these important animal diseases. In recent years, pestiviruses have shown great potential as viral vectors for developing multivalent vaccines. This review analyzes the advantages and disadvantages of various pestivirus vaccines, including live attenuated pestivirus strains, genetically engineered marker pestiviruses, and pestivirus-based multivalent vaccines. This review provides new insights into the development of novel vaccines against emerging pestiviruses, such as APPV and ovine pestivirus.

A new (old) bovine viral diarrhea virus 2 subtype: BVDV-2e

Bovine pestiviruses are members of the species Pestivirus A (bovine viral diarrhea virus 1, BVDV-1), Pestivirus B (BVDV-2) or Pestivirus H (HoBiPeV). To date, BVDV-2 isolates/strains have been classified into three subtypes (a-c) by phylogenetic analysis, and an additional subtype (d) has been proposed based on 5' untranslated region (UTR) secondary structures. In a previous study, we identified some BVDV-2 sequences in the GenBank database that could not be classified as subtype a, b or c by phylogenetic analysis of their genomes, UTRs or individual genes. Here, we performed a detailed study of these sequences and assessed whether they might represent a distinct BVDV-2 subtype. Initially, we collected 85 BVDV-2 complete/near-complete genomes (CNCGs) from GenBank and performed a "proof of equivalence" between phylogenetic analyses based on CNCGs and open reading frames (ORFs), which showed that ORFs may be reliably used as a reference target for BVDV-2 phylogeny, allowing us to increase our dataset to 139 sequences. Among these, we found seven sequences that could not be classified as BVDV-2a-c. The same was observed in the phylogenetic analysis of CNCGs and viral genes. In addition, the seven non-BVDV-2a-c sequences formed a distinct cluster in all phylogenetic trees, which we propose to term BVDV-2e. BVDV-2e also showed 44 amino acid changes compared to BVDV-2a-c, 20 of which are in well-defined positions. Importantly, an additional phylogenetic analysis including BVDV-2d and a pairwise comparison of BVDV-2e and BVDV-2d sequences also supported the difference between these subtypes. Finally, we propose the recognition of BVDV-2e as a distinct BVDV-2 subtype and encourage its inclusion in future phylogenetic analyses to understand its distribution and evolution.

A systematic review of the methods used to analyze the economic impact of endemic foot-and-mouth disease

Foot-and-mouth disease (FMD) has large economic consequences in livestock systems, which must be robustly assessed to support disease control policy. This study described and assessed methods used within economic analyses of FMD and its control in endemic contexts. A systematic literature search was conducted in six academic search engines. Studies were included if they applied an economic analysis to a context with endemic FMD, producing a result articulated as a monetary figure. Data collected from each article included country of study, animal population, geographical level of analysis, time horizon and type of economic analysis. Each study was scored using a quality assessment tool containing a checklist of 42 reporting criteria. Sixty-four articles were included, from 12,087 identified in the searches, describing results for 26 countries. Over half of the articles (56%) described economic impact of FMD retrospectively, often only accounting for a selection of direct costs at farm or household level. Median quality score calculated was 41% (range 8%-86%). Methods were generally poorly reported, confirming previously described difficulties in using published data to evaluate economic impact of endemic FMD. Few studies included disaggregation of public and private costs, or benefits, of FMD control, or accounted for economic or social influences of scale in vaccination programmes. Many of the studies included had gaps in both premise and methodology. If these analyses are used when planning and budgeting FMD control programmes in endemic contexts, there is a risk of inefficient resource allocation.

Estimating the Effect of a Bovine Viral Diarrhea Virus Control Program: An Empirical Study on the Performance of Dutch Dairy Herds

More and more European countries have implemented a bovine viral diarrhea virus (BVDV) control program. The economic effects of such programs have been evaluated in simulations, but empirical studies are lacking, especially in the final stage of the program. We investigated the economic (gross margin) and production effects (milk yield, somatic cell count, and calving interval) of the herds obtaining BVDV-free certification based on longitudinal annual accounting and herd performance data from Dutch dairy herds between 2014 and 2019, the final stages of the Dutch national BVDV-free program. This study was designed as a case-control study: two types of case herds were defined for two analyses. The case herds in the first analysis are herds where the BVDV status changed from “BVDV not free” to “BVDV free” during the study period. The not-free status refers to a herd that participated in the BVDV-free program but had not yet obtained the BVDV-free certification. In the second analysis, the case herds started participating in the Dutch BVDV-free program during the study period and obtained the BVDV-free certification. Control herds in both analyses were BVDV-free during the entire study period. Potential bias between the covariates of the two herd groups was reduced by matching case and control herds using the propensity score matching method. To compare the differences between case and control herds before and after BVDV-free certification, we used the time-varying Difference-in-Differences estimation (DID) methodology. The results indicate that there was no significant change in milk yield, somatic cell count, calving interval, and gross margin upon BVDV-free certification. There are several possible explanations for the non-significant effects observed in our study, such as the final stage of the BVDV control program, not knowing the true BVDV infection situation in case herds and not knowing if control measures were implemented in case herds prior to participating in the BVDV-free program. In our study, the effects of BVDV-free certification might have been underestimated, given that the Dutch BVDV control program became mandatory during the study period, and some of the case herds might have never experienced any BVDV infection. The results of this study suggest that in the final stage of the BVDV control program, the program may no longer have a clear benefit to the herd performance of participating dairy herds. When designing national programs to eradicate BVDV, it is therefore important to include incentives for such farms to motivate them to join the program.

[Genetic diversity and distribution of bovine pestiviruses (Flaviviridae: Pestivirus) in the world and in the Russian Federation]

The genus Pestivirus of the family Flaviviridae includes 11 species. Bovine pestiviruses are the causative agents of viral diarrhea/mucosal disease and include three genetically distinct species: pestivirus A (BVDV-1), B (BVDV-2), and H (BVDV-3). The number of BVDV-1 subtypes is 21, BVDV-2 - 4, and BVDV-3 - 4, which complicates the diagnosis of associated diseases, reduces the effectiveness of vaccination and control programs.We performed the search in the PubMed, Web of Science, Scopus, eLIBRARY.RU databases for articles published in 2000-2021.Pestivirus A is distributed everywhere, although the largest number of subtypes was found in cattle in Italy and China. The virus is widespread in the Central region of the Russia (subtypes 1a and 1m). In Siberia, eleven subtypes circulate among native and imported animals: 1a (5%), 1b (35%), 1c (5%), 1d (10%), 1f (20%), 1g, 1i (both 2.5%), 1j, 1k, 1p, and 1r (all for 5%). Pestivirus B subtype is more virulent, found less frequently and mainly in the North and South America, in some European countries, and in Asia. Three subtypes have been identified in Siberia: 2a (25%), 2b (10%), and 2c (5%). Pestivirus H circulates in Europe, Asia and South America. The main route of entry is contaminated biological products. In Russia, BVDV-3 of the Italian-Brazilian group (3a) was detected in 7 lots of fetal bovine serum.The role of the virus in the occurrence of respiratory diseases in calves, abortion, systemic infection and enteritis in calves and adult animals has been established. The source of the virus in such cases was a contaminated modified live vaccine.

The Epidemiology and Control of Bovine Viral Diarrhoea Virus in Tropical Indonesian Cattle

This review aims to update the knowledge of the epidemiology of Bovine viral diarrhoea virus (BVDV) in Indonesia and Southeast Asia and provide a perspective on the control options for BVDV in the Indonesian cattle population in the future. Studies on BVDV in Indonesia, since its first report in that country, and the updated beef and dairy cattle industries are reviewed. In ten of 34 provinces, BVDV is endemic. The subgenotypes of BVDV-1a and BVDV-1c are predominant in Indonesian cattle. However, BVDV is currently not a priority disease to control in Indonesia. Cattle imports from Australia appear to be potentially the most significant source of transmission of BVDV into native cattle, but the control of BVDV conducted in the local quarantine facilities is currently not achieving the aim of controlling BVDV; thus, complementary measures are needed. With the small-scale nature of the vast majority of cattle breeding in the country, the control of BVDV in provinces in which cattle breeding is economically essential may need to be organised by regional and provincial governments. Gaps in our knowledge of BVDV are identified in this review, and strategies for the control of BVDV in Indonesia are discussed.

Lack of Fetal Protection against Bovine Viral Diarrhea Virus in a Vaccinated Heifer

The aim of the report was to present the circulation of BVDV (bovine viral diarrhea virus) in the cattle population and determine the cause of the failure of vaccination failure leading to the birth of the PI (persistently infected) calf. The case study was carried out at the BVDV-free animal breeding center and cattle farm, where the vaccination program against BVDV was implemented in 2012, and each newly introduced animal was serologically and virologically tested for BVDV. In this case, a blood sample was taken from a 9-month-old breeding bull. Positive RT-PCR and negative ELISA serology results were obtained. The tests were repeated at 2-week intervals, and the results confirmed the presence of the virus and the absence of specific antibodies, i.e., persistent infection. Additionally, sequencing and phylogenetic analysis were performed, and the BVDV-1d subgenotype was detected. The results of this study showed that pregnant heifers and cows that are vaccinated multiple times with the killed vaccine containing BVDV-1a may not be fully protected against infection with other subgenotypes of BVDV, including their fetuses, which can become PI calves.

Efficacy of oleandrin and PBI-05204 against bovine viruses of importance to commercial cattle health

Background

Bovine viral diarrhea virus (BVDV), bovine respiratory syncytial virus (BRSV). and bovine coronavirus (BCV) threaten the productivity of cattle worldwide. Development of therapeutics that can control the spread of these viruses is an unmet need. The present research was designed to explore the in vitro antiviral activity of the Nerium oleander derived cardiac glycoside oleandrin and a defined N. oleander plant extract (PBI-05204) containing oleandrin.

Methods

Madin Darby Bovine Kidney (MDBK) cells, Bovine Turbinate (BT) cells, and Human Rectal Tumor-18 (HRT-18) cells were used as in vitro culture systems for BVDV, BRSV and BCV, respectively. Cytotoxicity was established using serial dilutions of oleandrin or PBI-05204. Noncytotoxic concentrations of each drug were used either prior to or at 12 h and 24 h following virus exposure to corresponding viruses. Infectious virus titers were determined following each treatment.

Results

Both oleandrin as well as PBI-05204 demonstrated strong antiviral activity against BVDV, BRSV, and BCV, in a dose-dependent manner, when added prior to or following infection of host cells. Determination of viral loads by PCR demonstrated a concentration dependent decline in virus replication. Importantly, the relative ability of virus produced from treated cultures to infect new host cells was reduced by as much as 10,000-fold at noncytotoxic concentrations of oleandrin or PBI-05204.

Conclusions

The research demonstrates the potency of oleandrin and PBI-05204 to inhibit infectivity of three important enveloped bovine viruses in vitro. These data showing non-toxic concentrations of oleandrin inhibiting infectivity of three bovine viruses support further investigation of in vivo antiviral efficacy.

Modeling the Effect of Bovine Viral Diarrhea Virus in Australian Beef Herds

Bovine viral diarrhea virus (BVDV) is an economically important disease in Australian beef farming. The disease typically results in low-level production losses that can be difficult to detect for several years. Simulation modeling can be used to support the decision to control BVDV; however, current BVDV simulation models do not adequately reflect the extensive farming environment of Australian beef production. Therefore, the objective of this study was to develop a disease simulation model to explore the impact of BVDV on beef cattle production in south-east Australia. A dynamic, individual-based, stochastic, discrete-time simulation model was created to simulate within-herd transmission of BVDV in a seasonal, self-replacing beef herd. We used the model to simulate the effect of herd size and BVDV introduction time on disease transmission and assessed the short- and long-term impact of BVDV on production outputs that influence the economic performance of beef farms. We found that BVDV can become established in a herd after a single PI introduction in 60% of cases, most frequently associated with the breeding period. The initial impact of BVDV will be more severe in smaller herds, although self-elimination is more likely in small herds than in larger herds, in which there is a 23% chance that the virus can persist for >15 years following a single incursion in a herd with 800 breeders. The number and weight of steers sold was reduced in the presence of BVDV and the results demonstrated that repeat incursions exacerbate long-term production losses, even when annual losses appear marginal. This model reflects the short- and long-term production losses attributed to BVDV in beef herds in southeast Australia and provides a foundation from which the influence and economic utility of BVDV prevention in Australian beef herds can be assessed.

Learning and strategic imitation in modelling farmers' dynamic decisions on bovine viral diarrhoea vaccination

Considering human decision-making is essential for understanding the mechanisms underlying the propagation of real-life diseases. We present an extension of a model for pathogen spread that considers farmers' dynamic decision-making regarding the adoption of a control measure in their own herd. Farmers can take into account the decisions and observed costs of their trade partners or of their geographic neighbours. The model and construction of such costs are adapted to the case of bovine viral diarrhoea, for which an individual-based stochastic model is considered. Simulation results suggest that obtaining information from geographic neighbours might lead to a better control of bovine viral diarrhoea than considering information from trade partners. In particular, using information from all geographic neighbours at each decision time seems to be more beneficial than considering only the information from one geographic neighbour or trade partner at each time. This study highlights the central role that social dynamics among farmers can take in the spread and control of bovine viral diarrhoea, providing insights into how public policy efforts could be targeted in order to increase voluntary vaccination uptake against this disease in endemic areas.

Th17 cell differentiation induced by cytopathogenic biotype BVDV-2 in bovine PBLCs

Background

Bovine viral diarrhea virus (BVDV) is a major pathogen that causes bovine viral diarrhea/mucosal disease (BVD-MD), which has become a global infectious disease due to its wide spread and the lack of effective treatment. The process of BVDV infection is complex. Once infected, host immune cells are activated and modulated. As a major immune cell, peripheral blood lymphocyte cells (PBLCs) are the primary target of BVDV. In order to further understand the mechanism of BVDV- host interaction, the expression profiles of host lymphocytes mRNAs associated with BVDV infection were investigated by transcriptomic sequencing analysis.

Results

The transcriptomic sequencing analysis was performed on bovine PBLCs infected with CP BVDV-2 GS2018 after 12 h of infection. Gene expression profiling demonstrated that 1052 genes were differentially expressed in GS2018 infected PBLCs compared with the control group. Of these genes, 485 genes were up-regulated and 567 were down-regulated. The 19 differential expressed genes (DEGs) were selected for validation using quantitative real-time PCR and the results were consistent with the results of RNA-Seq. Gene ontology enrichment and KEGG pathway analysis showed that 1052 DEGs were significantly enriched in 16 pathways, including cytokine-cytokine receptor interaction, IL17, PI3K-Akt, MAPK and TNF signaling pathway. PPI network analysis showed that IL17A, IFN-γ and TNF-α interacted with various proteins and may play crucial roles in BVDV-2 infection. Of note, we confirmed that GS2018 induced Th17 cell differentiation in PBLCs and persistently increased the expression levels of IL17A. In turn, the replication of GS2018 was inhibited by IL17A.

Conclusion

In this study, the transcription changes of DEGs related to host immune responses in bovine PBLCs were caused by CP BVDV-2 infection. In particular, the effector molecules IL17A of Th17 cells were significantly up-regulated, which inhibited viral replication. These results will contribute to exploration and further understanding of the host immune response mechanism and interaction between host and BVDV-2.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-08194-w.

75 years of bovine viral diarrhea virus: Current status and future applications of the use of directed antivirals

Bovine viral diarrhea virus (BVDV) was first reported 75 years ago and remains a source of major financial and production losses in the North American cattle industry. Currently, control methods in North America primarily center around biosecurity and vaccination programs; however, despite high levels of vaccination, the virus persists in the cattle herd due at least in part to the often-insidious nature of disease and the constant viremia and viral shedding of persistently infected animals which act as a reservoir for the virus. Continued development of targeted antivirals represents an additional tool for the prevention of BVDV-associated losses. Currently, in vivo studies of BVDV antivirals are relatively limited and have primarily been directed at the RNA-dependent RNA polymerase which represents the viral target with the highest potential for commercial development. Additional live animal studies have explored the potential of exogenous interferon treatment. Future research of commercial antivirals must focus on the establishment and validation of in vivo efficacy for compounds with demonstrated antiviral potential. The areas which provide the most viable economic justification for the research and development of antivirals drugs are the fed cattle sector, outbreak control, and wildlife or animals of high genetic value. With further development, targeted antivirals represent an additional tool for the management and control of BVDV in North American cattle herds.

Benefit of Bovine Viral Diarrhoea (BVD) Eradication in Cattle on Pestivirus Seroprevalence in Sheep

Bovine viral diarrhoea virus (BVDV) and Border disease virus (BDV) are closely related pestiviruses of cattle and sheep, respectively. Both viruses may be transmitted between either species, but control programs are restricted to BVDV in cattle. In 2008, a program to eradicate bovine viral diarrhoea (BVD) in cattle was started in Switzerland. As vaccination is prohibited, the cattle population is now widely naïve to pestivirus infections. In a recent study, we determined that nearly 10% of cattle are positive for antibodies to BDV. Here, we show that despite this regular transmission of BDV from small ruminants to cattle, we could only identify 25 cattle that were persistently infected with BDV during the last 12 years of the eradication program. In addition, by determining the BVDV and BDV seroprevalence in sheep in Central Switzerland before and after the start of the eradication, we provide evidence that BVDV is transmitted from cattle to sheep, and that the BVDV seroprevalence in sheep significantly decreased after its eradication in cattle. While BDV remains endemic in sheep, the population thus profited at least partially from BVD eradication in cattle. Importantly, on a national level, BVD eradication does not appear to be generally derailed by the presence of pestiviruses in sheep. However, with every single virus-positive cow, it is necessary to consider small ruminants as a potential source of infection, resulting in costly but essential investigations in the final stages of the eradication program.

To Vaccinate or Not: Impact of Bovine Viral Diarrhoea in French Cow-Calf Herds

Bovine viral diarrhoea (BVD) remains an issue despite control programs implemented worldwide. Virus introduction can occur through contacts with neighbouring herds. Vaccination can locally protect exposed herds. However, virus spread depends on herd characteristics, which may impair vaccination efficiency. Using a within-herd epidemiological model, we compared three French cow-calf farming systems named by their main breed: Charolaise, Limousine, and Blonde d’Aquitaine. We assessed vaccination strategies of breeding females assuming two possible protections: against infection or against vertical transmission. Four commercial vaccines were considered: Bovilis^®, Bovela^®, Rispoval^®, and Mucosiffa^®. We tested various virus introduction frequency in a naïve herd. We calculated BVD economic impact and vaccination reward. In Charolaise, BVD economic impact was 113€ per cow over 5 years after virus introduction. Irrespective of the vaccine and for a high enough risk of introduction, the yearly expected reward was 0.80€ per invested euro per cow. Vaccination should not be stopped before herd exposure has been decreased. In contrast, the reward was almost nil in Blonde d’Aquitaine and Limousine. This highlights the importance of accounting for herd specificities to assess BVD impact and vaccination efficiency. To guide farmers’ vaccination decisions against BVD, we transformed this model into a French decision support tool.

Eradication of Bovine Viral Diarrhoea (BVD) in Cattle in Switzerland: Lessons Taught by the Complex Biology of the Virus

Bovine viral diarrhoea virus (BVDV) and related ruminant pestiviruses occur worldwide and cause considerable economic losses in livestock and severely impair animal welfare. Switzerland started a national mandatory control programme in 2008 aiming to eradicate BVD from the Swiss cattle population. The peculiar biology of pestiviruses with the birth of persistently infected (PI) animals upon in utero infection in addition to transient infection of naïve animals requires vertical and horizontal transmission to be taken into account. Initially, every animal was tested for PI within the first year, followed by testing for the presence of virus in all newborn calves for the next four years. Prevalence of calves being born PI thus diminished substantially from around 1.4% to <0.02%, which enabled broad testing for the virus to be abandoned and switching to economically more favourable serological surveillance with vaccination being prohibited. By the end of 2020, more than 99.5% of all cattle farms in Switzerland were free of BVDV but eliminating the last remaining PI animals turned out to be a tougher nut to crack. In this review, we describe the Swiss BVD eradication scheme and the hurdles that were encountered and still remain during the implementation of the programme. The main challenge is to rapidly identify the source of infection in case of a positive result during antibody surveillance, and to efficiently protect the cattle population from re-infection, particularly in light of the endemic presence of the related pestivirus border disease virus (BDV) in sheep. As a consequence of these measures, complete eradication will (hopefully) soon be achieved, and the final step will then be the continuous documentation of freedom of disease.

The Principles of the Voluntary Programme for the Control and Elimination of Bovine Viral Diarrhoea Virus (BVDV) From Infected Herds in Slovenia

In Slovenia, the control of bovine viral diarrhoea virus (BVDV) infections started in 1994. Since 2014, a voluntary programme has been running according to the national rules that prescribe the conditions for recognising, acquiring, and maintaining a BVDV-free status for an individual herd. The principle is based on periodical laboratory testing and preventive measures that need to be strictly implemented in a herd. Between 2014 and 2020, a total of 348 herds were included in BVDV antibody testing, and 25.0% of tested herds were detected to be BVDV antibody positive. To recognise the BVDV-free status of the herd, the breeder should provide two consecutive tests with intervals of at least 6 months in all animals in the age from 7 to 13 months, with negative results for BVDV antibodies in ELISA. The BVDV-free status of the herd can be maintained by implementing preventive measures and can be renewed each year with one laboratory test in the age group of animals from 7 to 13 months for antibodies in ELISA. During the 7 years of the voluntary programme, 236 herds were included in the detection of BVDV in individual herds by real-time RT-PCR method and the elimination of positive animals from herds. In 71 (31.3%) herds, at least one BVDV-positive animal was detected, with the identification of a total of 267 persistently infected (PI) animals, representing an average of 2.9% of tested animals. The cost of testing for an average herd, recognised as BVDV-negative, and maintaining its BVDV-free status within the implemented voluntary programme, was €97.64/year, while for the average positive herd, the laboratory costs for elimination of BVDV were €189.59/year. Only limited progress towards eradication at the national level has been achieved in Slovenia since 2014.

Overview of Slovenian Control Programmes for Cattle Diseases Not Regulated by the European Union

The European Union (EU) regulates the control of cattle diseases listed in categories A and B of the European Animal Health Law (AHL). However, no strict mandatory EU regulation exists for the control of other cattle diseases that are listed in categories C, D and E. Slovenia has five control programmes (CPs) for the latter cattle diseases: bovine viral diarrhoea (BVD), infectious bovine rhinotracheitis (IBR), enzootic bovine leukosis (EBL), bluetongue and anthrax. Two (IBR and BVD) are voluntary and the others (EBL, anthrax and bluetongue) are compulsory. The three compulsory CPs are funded by the government. All the CPs are run by the government and laboratory tests are performed by the National Veterinary Institute. The rules for the CPs are laid down in Slovenian legislation. In addition, there is a national directive for the control of salmonellosis. Both BVD and IBR are endemic and have CPs based on increased biosecurity, testing and culling or vaccination, financed by the animal owners. Slovenia has been officially free of EBL since 2005 and carries out surveillance based on serological testing of a representative number of herds and inspection of carcasses at slaughter or necropsy. Vaccination is the main disease control measure for anthrax (sporadic) and bluetongue (currently perceived free—vaccination since 2017). Lack of motivation of farmers to participate in voluntary disease CPs and to implement and follow strict biosecurity measures are the most pressing issues in improving the health status of Slovenian cattle. An overview of the existing CPs and the circumstances leading to their implementation are presented.

Individual-based model for the control of Bovine Viral Diarrhea spread in livestock trade networks

Bovine Viral Diarrhea (BVD) is a cattle disease that causes substantial financial losses, in particular to the dairy industry. Hence, several countries including Germany introduced compulsory disease control programs. For the case of Germany in particular, all animals had to be tested and persistently infected animals (PI animals) were removed from the population. The program was successful in reducing the number of PI animals, but was overtly expensive. Alternative approaches were therefore discussed to eliminate the remaining PI animals and alter the testing system in order to reduce costs. Contributing to these efforts, we developed an agent-based model that aimed to cover all relevant aspects of the disease biology and would allow to evaluate different control strategies. For the biological part of the infection spread, the model includes horizontal and vertical transmission, transient and persistent infections. Moreover, several control strategies including import of animals, trade restrictions, vaccination, as well as various testing schemes were included. The model was furthermore defined to be stochastic, event-driven and hierarchical, with cattle movements as the main route of spreading between farms. For the spread within farms, we included susceptible-infected-recovered (SIR) dynamics with an additional permanently infectious class. The interaction between the farms was described by a supply and demand farm manager mechanism governing the network structure and dynamics. Additionally, we carried out a sensitivity analysis of the input parameters to study the impact of extreme values on the model. Since the population size in the model is limited, we tested the influence of the initial population size on the model results. Our results showed that the model could accurately describe the dynamics of the disease in the presence and absence of disease control. Although we developed the model for the spread of BVD, it may be adapted to similar diseases of cattle and swine.

Broad detection and quick differentiation of bovine viral diarrhea viruses 1 and 2 by a reverse transcription loop-mediated isothermal amplification test

For broad detection of pestivirus A (bovine viral diarrhea virus 1: BVDV1) and pestivirus B (BVDV2) by a reverse transcription loop-mediated isothermal amplification (RT-LAMP) test, the P25 primer set was designed using nucleotide sequences of 5'-UTR region of 1454 BVDVs. The base coverage of each primer against diverse BVDVs were more than 99% in each base position. The one step LAMP test with the P25 primer set could detect both BVDV1 (TK) and BVDV2 (KZ), but did not amplify 5 other bovine viruses. Detection limit of the LAMP test was 10³ copies of synthesized DNAs, and 10^-3 and 10^-4 dilutions of viral RNAs of TK and KZ strains, respectively, whereas that with current Aebischer's primer set was 10^-2 dilution and negative of these RNAs, respectively. All of the 63 viral RNA samples of persistently infected (PI) cattle, consisting of the 1a (12), 1b (31), 1c (11), and 2a (9) subgenotypes, were broadly detected with the P25, while only 65% of them were positive with Aebischer's primer set. The validation study showed that the RT-LAMP test with the P25 had 100% sensitivity and 100% specificity against that with updated Vilcek's PCR primers. Also, by using the P26 primer set which contained 3 species-specific primers, all 63 RNA samples were clearly distinguished from BVDV1 or BVDV2 by the typing RT-LAMP test. These results indicate that the one step RT-LAMP test using P25 or P26 primer sets would be useful for broad detection and rapid differentiation of BVDV1 and BVDV2.

Cryptosporidium spp. Infections in Combination with Other Enteric Pathogens in the Global Calf Population

Simple Summary

The factors “diagnostic”, “health status of the sampled animals”, and “geographical region” explained the majority of the variance of Cryptosporidium spp. (Crypto) prevalence in the global calf population across the literature. The chance of detecting bovine rotavirus (BRV), bovine coronavirus (BCoV), and enterotoxigenic Escherichia coli F5 (K99) (ETEC) in calves with diarrhoea was lower in the presence of Crypto compared to calves without Crypto. This may indicate an inhibition effect between BRV, BCoV, ETEC, and Crypto.

Abstract

The most common worldwide diarrhoea-causing agents in neonatal calves are Cryptosporidium spp. (Crypto), bovine rotavirus (BRV), bovine coronavirus (BCoV), and enterotoxigenic Escherichia coli F5 (K99) (ETEC). Crypto is a zoonotic pathogen of diarrhoea in humans, particularly for children and immunocompromised adults. Four weighted-stratified random-effect meta-analyses including meta-regression analyses were performed to calculate the worldwide mean prevalence of Crypto and associated concurrent infections with BRV, BCoV and ETEC, as well as their potential influencing factors. The meta-analysis incorporated 28 studies (56 substudies) in 17 countries that determined the presence or absence of concurrent infections with Crypto in the global calf population. Approximately half of all considered studies presented here were conducted in Europe independently of the type of infections with Crypto. Within Europe, the highest estimated mean Crypto-BRV prevalence was identified in Ireland (16.7%), the highest estimated mean Crypto-BCoV prevalence was detected in the United Kingdom (4.3%), and the highest estimated mean Crypto-ETEC prevalence across the literature was determined in Turkey (4.7%). The chance of detecting BRV, BCoV, and ETEC in calves with diarrhoea was 0.8 (confidence interval (CI): 0.6–1.0), 0.7 (CI: 0.5–1.0) and 0.6 (CI: 0.4–0.9) lower in the presence of Crypto compared to calves without Crypto. This may indicate an inhibitory effect between BRV, BCoV, ETEC, and Crypto in calves. The variance in the published prevalence across the literature can mainly be explained by the “diagnostic” factor (R² min–max: 0.0–40.3%), followed by the “health status of the sampled animals” (R² min–max: 1.4–27.3%) and “geographical region” (R² min–max: 5.9–23.6%).

Overview of Mitigation Programs for Non-EU-Regulated Cattle Diseases in Austria

Background: The non-mandatory regulation of animal diseases at the European Union (EU) level enables member states to implement mitigation programs based on their own country-specific conditions such as priority settings of the governments, availability of financial resources, and epidemiological situation. This can result in a heterogeneous distribution of mitigation activities and prevalence levels within and/or between countries, which can cause difficulties for intracommunity trade. This article aims to describe the past, current, and future mitigation activities and associated prevalence levels for four animal diseases, i.e., enzootic bovine leukosis (EBL), infectious bovine rhinotracheitis/infectious pustular vulvovaginitis (IBR/IPV), bovine viral diarrhea (BVD), and bluetongue disease (BT) for Austria. Over a period of 40 years (1978–2020), regulations concerning EBL, IBR/IPV, BVD, and BT were retraced to analyze the changes of legislation, focusing on sampling, testing, and mitigation activities in Austria, and were linked to the collected diagnostic testing results. The study results clearly demonstrate the adoption of the legislation by the Austrian governments in dependency of the epidemiological situations. Furthermore, our study shows that, related to the forthcoming Animal Health Law on April 21, 2021, Austria has a good initial situation to achieve disease-free status and/or free from infection status based on the current available epidemiological situation and previously implemented mitigation activities. The study results presented here are intended to contribute to a better comparison of the eradication status across European countries for cattle diseases by providing information about the mitigation activities and data of testing results over a period of 40 years.

Triazolopyrimidine Nuclei: Privileged Scaffolds for Developing Antiviral Agents with a Proper Pharmacokinetic Profile

Viruses are a continuing threat to global health. The lack or limited therapeutic armamentarium against some viral infections and increasing drug resistance issues make the search for new antiviral agents urgent. In recent years, a growing literature highlighted the use of triazolopyrimidine (TZP) heterocycles in the development of antiviral agents, with numerous compounds that showed potent antiviral activities against different RNA and DNA viruses. TZP core represents a privileged scaffold for achieving biologically active molecules, thanks to: i) the synthetic feasibility that allows to variously functionalize TZPs in the different positions of the nucleus, ii) the ability of TZP core to establish multiple interactions with the molecular target, and iii) its favorable pharmacokinetic properties. In the present review, after mentioning selected examples of TZP-based compounds with varied biological activities, we will focus on those antivirals that appeared in the literature in the last 10 years. Approaches used for their identification, the hit-to-lead studies, and the emerged structure-activity relationship will be described. A mention of the synthetic methodologies to prepare TZP nuclei will also be given. In addition, their mechanism of action, the binding mode within the biological target, and pharmacokinetic properties will be analyzed, highlighting the strengths and weaknesses of compounds based on the TZP scaffold, which is increasingly used in medicinal chemistry.

Practices and opinions of New Zealand veterinarians regarding control of bovine viral diarrhoea

AIMS

To explore recommendations that New Zealand veterinarians make for diagnosing and managing bovine viral diarrhoea (BVD) in cattle herds under different clinical scenarios and their opinions towards potential barriers and opportunities for implementing BVD control programmes in New Zealand.

METHODS

A cross-sectional survey of registered veterinarians in New Zealand was conducted in 2019. Respondents were asked about the approaches they would use to manage BVD under different clinical scenarios as well as their opinions on national BVD control. A subset of veterinarians completed a more in-depth survey providing additional free-text responses on a range of different BVD topics. Descriptive statistics were provided for all quantitative study variables and the free-text responses were also analysed to generate further insights into veterinarians' perceptions towards BVD management.

RESULTS

The cross-sectional survey was completed by 101 of an estimated 870 (11.6%) cattle veterinarians. Thirty-five veterinarians completed the in-depth survey. There was wide variation in the BVD diagnostic testing and vaccination protocols that respondents recommended under different clinical scenarios. Annual bulk milk BVD testing was perceived as a valuable tool for initiating BVD discussions with dairy farmers. Respondents indicated that beef farmers were more difficult to engage in BVD control largely due to the logistical challenges of yarding cattle at the appropriate times to implement interventions, with many farmers only contacting veterinarians after experiencing a BVD outbreak Most respondents (91/101; 90%) believed it was possible to eradicate BVD from New Zealand, but cited lack of farmer awareness and poor compliance with management recommendations as significant barriers. The measure with the most support for inclusion in a compulsory national eradication programme was requiring farmers to declare the status of their animals prior to sale while the least supported measure was requiring farmers to double fence boundaries to prevent nose-to-nose contact with neighbouring stock. Although respondents highlighted the need for farmers and industry to support any national eradication programme in order for it to be successful, there was also recognition that veterinarians could be more pro-active in engaging with farmers particularly in discussions around the economics of BVD.

CONCLUSIONS AND CLINICAL RELEVANCE

While the survey respondents appeared to be highly supportive of BVD control, it was perceived that financial and logistical barriers existed that could impede farmer engagement. Further extension efforts may be needed to ensure that veterinarians are presenting clear and consistent recommendations about BVD management to farmers.Abbreviations: BVD: Bovine viral diarrhoea; NAIT: National Animal Identification and Tracing System; PI: Persistently infected.

[Detection of bovine pestiviruses by a multiplex real-time polymerase chain reaction.]

INTRODUCTION

Pestiviruses are the cause of reproductive problems, diseases of the gastrointestinal and respiratory tracts of animals. Three species are important for cattle: Pestivirus A, B, and H. Fast and reliable methods of differentiation of these pathogens are currently needed. Aims and objectives of the study: the development of multiplex real time PCR for the simultaneous detection and differentiation of three viruses.

MATERIAL AND METHODS

The nucleotide sequences of the conserved regions of the 5´-UTR genes of pes tivirusesA, B, and H served as a target.

RESULTS

The reaction showed high specificity, sensitivity, reproducibility and was able to detect virus RNA at a concentration of not less than 0.6-1.2 lg TCID_50/cm³. Cross-reactions with other pestiviruses wer e not observed. Real time PCR confirmed the results obtained previously in RT-PCR with gel electrophoresis detection. In a parallel study of 1823 biological samples, the results of the two reactions were completely consistent. Pestivirus spp. was detectedin 76 samples, Pestivirus A was present in 73 samples, Pestivirus B - in 3 samples, and Pestivirus H was not detected.

DISCUSSION

A two-step real time PCR was developed for the simultaneous detection and differentiation of three pestiviruses. Modified pan primers of S. Vilcek et al. were used for the first reaction, and primers and probes of our own design were used for virus typing, which resulted in high reaction efficiency.

CONCLUSION

On the big dairy farms for livestock maintenance, there are favorable conditions for the circulation of pathogenic viruses. In this situation, rapid diagnostic methods are needed to quickly identify of several viruses. Real-time triplex analysis can be recommended as the rapid method for mass epidemiological studies, as well as for screening fetal calf serum used for virus cultivation in medicine and veterinary practice.

Induction of Robust and Specific Humoral and Cellular Immune Responses by Bovine Viral Diarrhea Virus Virus-Like Particles (BVDV-VLPs) Engineered with Baculovirus Expression Vector System

Bovine viral diarrhea virus (BVDV) is an important animal pathogen that affects cattle. Infections caused by the virus have resulted in substantial economic losses and outbreaks of BVDV are reported globally. Virus-like particles (VLPs) are promising vaccine technology largely due to their safety and strong ability to elicit robust immune responses. In this study, we developed a strategy to generate BVDV-VLPs using a baculovirus expression vector system (BEVS). We were able to assemble BVDV-VLPs composed of dimerized viral proteins E2 and E^rns, and the VLPs were spherical particles with the diameters of about 50 nm. Mice immunized with 15 μg of VLPs adjuvanted with ISA201 elicited higher levels of E2-specific IgG, IgG1, and IgG2a antibodies as well as higher BVDV-neutralizing activity in comparison with controls. Re-stimulation of the splenocytes collected from mice immunized with VLPs led to significantly increased levels of CD3⁺CD4⁺T cells and CD3⁺CD8⁺T cells. In addition, the splenocytes showed dramatically enhanced proliferation and the secretion of Th1-associated IFN-γ and Th2-associated IL-4 compared to that of the unstimulated control group. Taken together, our data indicate that BVDV-VLPs efficiently induced BVDV-specific humoral and cellular immune responses in mice, showing a promising potential of developing BVDV-VLP-based vaccines for the prevention of BVDV infections.

Prevalence of Worldwide Neonatal Calf Diarrhoea Caused by Bovine Rotavirus in Combination with Bovine Coronavirus, Escherichia coli K99 and Cryptosporidium spp.: A Meta-Analysis

Multiple enteropathogens such as bovine rotavirus (BRV), bovine coronavirus (BCoV), Escherichia coli K99 (ETEC) and Cryptosporidium spp. (Crypto) are the most common causes of calf diarrhoea during the first 30 days of animal age. Three weighted-stratified random-effects meta-analyses were performed to calculate the worldwide prevalence of mixed infections of the causative agents (i.e., BRV-BCoV, BRV-ETEC, BRV-Crypto) and their potential influencing factors. The meta-analysis covered 41 studies (94 sub-studies) in 21 countries that determined the presence or absence of mixed infections in global calf populations. The highest worldwide estimated pooled prevalence was identified for BRV-Crypto (6.69%), followed by BRV-BCoV (2.84%), and BRV-ETEC (1.64%). The chance of detecting BCoV in calves with diarrhoea was 1.83 higher in the presence of BRV compared to calves without BRV, whereby an inhibition effect (odds ratio: 0.77) was determined between BRV and Crypto infections. The diagnostic methods were identified as a significant influencing factor in the detection of all considered mixed infections, while the other analysed factors differed in relation to their effect on prevalence. In contrast to BRV-BCoV, the prevalence of BRV-ETEC and BRV-Crypto mixed infections followed the course of individual ETEC and Crypto prevalence related to the age class of the sampled animals.

Effect of calf age on bovine viral diarrhea virus tests

Bovine viral diarrhea virus (BVDV) causes significant economic loss in cattle. Detection of persistently infected (PI) animals is an important control measure, but persistence of maternal antibodies may result in false-negative test results. We assessed the sensitivity and specificity of 2 antigen ELISAs (Idexx BVDV Ag/Serum Plus and BVDV PI X2) and a reverse-transcription real-time PCR (RT-rtPCR; Idexx RealPCR BVDV) assay for detecting PI calves. Ear notch samples were collected from 1,030 calves ~3, 10, 24, and 38 d old (days 3, 10, 24, and 38). All day 38 samples were tested using 2 antigen ELISAs and RT-rtPCR, and any calf that tested positive by any of these tests was blood sampled at ~100 d old (day 100) for antigen and antibody testing by ELISA; samples collected on days 3, 10, and 24 were tested using the antigen ELISAs and PCR. Calves were defined as PI if they were test-positive on day 38 by either ELISA or PCR and were antigen-positive on day 100. Twenty-six calves were PCR BVDV test-positive and one was BVDV PI X2 ELISA-positive at day 38. Five calves were defined as PI, and all tested positive by ELISAs and RT-PCR assay on days 3, 10, and 24. The sensitivity and specificity were 100% for both antigen ELISAs and 96.7% and 100%, respectively, by RT-rtPCR. Test results were not affected by calf age, suggesting that testing for PI calves can be undertaken at any age.

Prevalence of bovine abortion, calf mortality, and bovine viral diarrhea virus (BVDV) persistently infected calves among pastoral, peri-urban, and mixed-crop livestock farms in central and Northwest Ethiopia

Background

Bovine Viral Diarrhea virus (BVDV) is one of important diseases of cattle worldwide causing economic losses to the cattle industry primarily due to increased premature culling and decreased reproductive performance. The virus can cross the placenta during early pregnancy and result in the birth of persistently infected (PI) calves that are efficient transmitters of BVDV and serving as the primary reservoirs for BVDV. Relatively few studies have focused on understanding BVDV seroprevalence, virus detection, genotyping and its distribution in Africa. Most BVDV research in Ethiopia has involved serologic surveys in adult cattle, rather than the identification of PI calves, despite their role in viral shedding and recurring infections. A cross-sectional study was undertaken in three different livestock production systems of Ethiopia with the objective to estimate the prevalence of bovine abortion, calf mortality, and BVDV persistently infected calves.

Results

Ear notch samples (882) collected from calves in 349 households were tested for BVDV antigen using antigen capture enzyme-linked immunosorbent assay (ACE). All samples tested were negative for BVDV antigen. The overall animal level crude abortion and calf mortality prevalence were 4.0% (95% CI: 2.9–5.2) and 9.2% (95% CI: 7.7–11.0) respectively. The lower BVDV PI prevalence may be due to a lower effective contact rate between cattle reared in small-scale extensive production systems in Ethiopia.

Conclusions

This is the first report of BVDV Ag test in Ethiopia and no PI was detected in calves in the study areas. Since BVDV is a disease of great economic importance, this study finding must be interpreted with care since absence of evidence is not evidence of absence and even a single BVDV infected animal can serve as source of infection and contribute to the persistent spread of the virus. Greater attention needs to be given to screening for PI animals through testing large number of animals and culling positive animals. Hence, future research should focus on regions and production systems with high BVDV seroprevalence followed by antigen ELISA or BVDV real-time PCR to detect persistently infected and acutely viremic animals.

Frequency of bovine viral diarrhea virus (BVDV) in Argentinean bovine herds and comparison of diagnostic tests for BVDV detection in bovine serum samples: a preliminary study

Bovine viral diarrhea (BVD) is a major worldwide disease with negative economic impact on cattle production. Successful control programs of BVD require the identification and culling of persistently infected (PI) animals with bovine viral diarrhea virus (BVDV). A variety of diagnostic tests are available to detect BVDV, but no comparison has been performed among those tests in Argentina. Sera collected from 2864 cattle, belonging to 55 herds from three Argentinean provinces, were analyzed by nested RT-PCR (RT-nPCR) to detect BVDV for diagnostic purposes. Additionally, this study evaluated the agreement of the RT-nPCR along with virus isolation, antigen-capture ELISA, and real-time RT-PCR for BVDV detection in archived bovine serum samples (n = 90). The RT-nPCR was useful for BVDV detection in pooled and individual serum samples. BVDV was detected in 1% (29/2864) of the cattle and in 20% (11/55) of the herds. The proportion of BVDV-positive sera was not statistically different among the tests. In addition, comparisons showed high agreement levels, with the highest values between both RT-PCR protocols. The frequency of BVDV infection at individual and herd level was lower than the reported values worldwide. Since follow-up testing was not performed, the frequency of PI cattle was unknown. Also, this study demonstrated that the four diagnostic tests can be used reliably for BVDV identification in individual serum samples. Further epidemiologically designed studies that address prevalence, risk factors, and economic impact of BVDV in Argentina will be necessary to implement effective control programs.

Selection for Favorable Health Traits: A Potential Approach to Cope with Diseases in Farm Animals

Disease is a global problem for animal farming industries causing tremendous economic losses (>USD 220 billion over the last decade) and serious animal welfare issues. The limitations and deficiencies of current non-selection disease control methods (e.g., vaccination, treatment, eradication strategy, genome editing, and probiotics) make it difficult to effectively, economically, and permanently eliminate the adverse influences of disease in the farm animals. These limitations and deficiencies drive animal breeders to be more concerned and committed to dealing with health problems in farm animals by selecting animals with favorable health traits. Both genetic selection and genomic selection contribute to improving the health of farm animals by selecting certain health traits (e.g., disease tolerance, disease resistance, and immune response), although both of them face some challenges. The objective of this review was to comprehensively review the potential of selecting health traits in coping with issues caused by diseases in farm animals. Within this review, we highlighted that selecting health traits can be applied as a method of disease control to help animal agriculture industries to cope with the adverse influences caused by diseases in farm animals. Certainly, the genetic/genomic selection solution cannot solve all the disease problems in farm animals. Therefore, management, vaccination, culling, medical treatment, and other measures must accompany selection solution to reduce the adverse impact of farm animal diseases on profitability and animal welfare.

Introduction and elimination of Bovine Viral Diarrhoea Virus in a commercial beef herd: a case study

Routine Bovine Viral Diarrhoea Virus (BVDV) monitoring of a commercial beef herd in southern New South Wales over a 10-year period provided an opportunity to assess the impact of the introduction of BVDV on that herd. BVDV antibody testing provided strong evidence that the herd was initially free of BVDV (2009-2011). Testing from 2012 suggested BVDV had been introduced into the herd and this was confirmed in 2015 with the identification of persistently infected (PI) animals. Having become established in the herd, the owners then set out to eliminate BVDV from the herd. Antigen testing aimed at identifying PI animals revealed BVDV was already absent from the herd. Subsequent antibody testing confirmed that the herd was now free from BVDV. Despite the incursion of BVDV in this herd, there was little measurable impact on reproductive performance (pregnancy rates), although suspected increased calf losses from birth to calf marking were reported. This is the first time such self-clearance has been documented as part of a longitudinal study under Australian conditions.

A survey of biosecurity measures and serological status for bovine viral diarrhoea virus and bovine herpesvirus 1 on dairy cattle farms in north-west and north-east Spain

BACKGROUND

Biosecurity is a key measure to reduce and prevent the introduction of diseases to farms and minimise spread of diseases within a herd. The aim of the study was to characterise the current application of biosecurity measures on dairy cattle farms in Spain along with their bovine viral diarrhoea and infectious bovine rhinotracheitis status.

METHODS

Data on biosecurity measures for 124 dairy herds were collected using a questionnaire. The sanitary status of these farms for bovine viral diarrhoea and infectious bovine rhinotracheitis was also assessed using antibody ELISA. Data were analysed using multiple correspondence analysis and a two-step cluster analysis.

RESULTS

Three main clusters of farms were identified: clusters 1 and 2 included herds of small and intermediate sizes. These, particularly cluster 1, showed the most deficiencies in the control of vehicles and visitors. However, laboratory tests were always performed on purchased animals. Cluster 3 had the largest herd sizes, with somewhat better biosecurity control of vehicles and visitors. However, farms in this cluster also purchased the most animals, sometimes without testing, and hired external workers more often.

CONCLUSION

The study indicated that, in the study population, there are serious shortcomings in the application of biosecurity measures on dairy farms, exposing them to disease transmission. This survey also highlights regional and herd size-related differences in the implementation of biosecurity. Collecting data is an important first step to identification of specific weaknesses in different farm typologies, and an adequate follow-up is needed to ensure that measures are implemented correctly on farms.

Veterinarians' Knowledge, Attitudes and Practices Associated with Bovine Viral Diarrhoea Virus Control and Prevention in South-East Australia

Simple Summary

Bovine Viral Diarrhoea Virus is a disease of cattle that causes production losses. Despite the virus being widespread across Australia, there are no government or industry-led programs to mitigate the impacts or eliminate Bovine Viral Diarrhoea Virus. Veterinarians were surveyed about their knowledge, attitudes and recommended practices regarding Bovine Viral Diarrhoea Virus and its control. We found that veterinarians’ knowledge of Bovine Viral Diarrhoea Virus in their region is limited, and their attitudes and recommendations for controlling the virus do not always align with those of producers. For example, veterinarians are concerned about the welfare and potential for disease spread associated with control measures involving persistently infected cattle, including a previously undocumented practice in which producers administer blood from persistently infected cattle into naïve cattle as a form of vaccination. This study highlights that a greater understanding of producers’ and veterinarians’ values is needed before Bovine Viral Diarrhoea Virus control could be implemented at a regional or country level.

Abstract

In Australia, the responsibility and associated costs for the control and prevention of Bovine Viral Diarrhoea Virus (BVDV) rest solely with producers. Veterinarians provide producers with farm-specific options for BVDV management and support BVDV control and elimination in their region. We surveyed veterinarians to determine their knowledge, attitudes and practices (KAP) associated with BVDV control in south-east Australia. We found that veterinarians’ recommendations do not always align with producers’ control measures. Veterinarians were uncertain about BVDV prevalence and the proportion of producers using BVDV control measures in their regions. Veterinarians generally promoted biosecurity and vaccination, and were concerned about the welfare and additional disease risks associated with persistently infected (PI) cattle. Veterinarians highlighted concerns about disease risks associated with a previously undocumented practice in which producers collect blood from PI cattle to administer to BVDV naïve cattle; termed “vampire vaccination” in this study. A greater understanding of the burden, impact and economics of BVDV is needed to align veterinarians’ and producers’ KAP to improve BVDV management on farms, and more appreciation of veterinarians’ and producers’ values is needed before BVDV control could be implemented at a regional or country level.

Prevalence and risk factors of bovine viral diarrhea in Colombian cattle

Background and Aim:

Bovine viral diarrhea virus (BVDV) is present in most cattle-raising countries around the world, and it has a negative economic impact in cattle herds. In Colombia, previous studies have estimated the prevalence of BVDV in specific locations. The aim of this study was to estimate the prevalence of BVDV in cattle herds located at several municipalities across the country and to identify the associated risk and protective factors.

Materials and Methods:

A cross-sectional study was carried out to investigate the prevalence of BVDV in Colombian cattle populations at farm and animal-levels. A total of 387 herds and 8110 animals located in seven different departments were included in this study.

Results:

An animal- and farm-level prevalence of 36% and 69%, respectively, were estimated. A high variation for the farm-level prevalence was found among the municipalities studied. Moreover, seropositive cattle to the infectious bovine rhinotracheitis virus (odds ratio (OR)=2.38, p=0.0479) and Neospora caninum (OR=3.15, p=0.0122) were more likely to be seropositive for BVDV, while the practice of burning dead animals at the farm was identified as a protective factor (OR=0.17, p=0.014).

Conclusion:

The prevalence of BVDV varied more at farm-level compared to animal-level. Two risk factors and one protective factor were identified. The results of the current study are essential to understand the epidemiology of BVDV in Colombia, and to formulate strategies in the region to mitigate the impact of this virus on the productive and reproductive indicators of cattle farms at the regional level.

Fetal Lymphoid Organ Immune Responses to Transient and Persistent Infection with Bovine Viral Diarrhea Virus

Bovine Viral Diarrhea Virus (BVDV) fetal infections occur in two forms; persistent infection (PI) or transient infection (TI), depending on what stage of gestation the fetus is infected. Examination of lymphoid organs from both PI and TI fetuses reveals drastically different fetal responses, dependent upon the developmental stage of the fetal immune system. Total RNA was extracted from the thymuses and spleens of uninfected control, PI, and TI fetuses collected on day 190 of gestation to test the hypothesis that BVDV infection impairs the innate and adaptive immune response in the fetal thymus and spleen of both infection types. Transcripts of genes representing the innate immune response and adaptive immune response genes were assayed by Reverse Transcription quatitative PCR (RT-qPCR) (2^−ΔΔCq; fold change). Genes of the innate immune response, interferon (IFN) inducible genes, antigen presentation to lymphocytes, and activation of B cells were downregulated in day 190 fetal PI thymuses compared to controls. In contrast, innate immune response genes were upregulated in TI fetal thymuses compared to controls and tended to be upregulated in TI fetal spleens. Genes associated with the innate immune system were not different in PI fetal spleens; however, adaptive immune system genes were downregulated, indicating that PI fetal BVDV infection has profound inhibitory effects on the expression of genes involved in the innate and adaptive immune response. The downregulation of these genes in lymphocytes and antigen-presenting cells in the developing thymus and spleen may explain the incomplete clearance of BVDV and the persistence of the virus in PI animals while the upregulation of the TI innate immune response indicates a more mature immune system, able to clear the virus.

Knowledge, attitudes and management of bovine viral diarrhoea virus among eastern Australian cattle producers: results from a 2013 cross-sectional study

Bovine viral diarrhoea virus (BVDV) is an economically significant disease affecting the Australian cattle industry, with losses stemming from decreased production and reproductive performance and control costs. However, these losses can be difficult to appreciate, particularly in endemic regions. Overall, there is a variable but high herd-level seroprevalence in Australia. Despite a potentially high financial burden of the disease, the onus for control ultimately falls on producers and strategies employed will vary between regions. A cross-sectional study, using a postal survey, was conducted in 2013 to evaluate the BVDV knowledge, attitudes and management practices utilised by Australian cattle producers. A total of 192 producers participated in the study, and results indicate that knowledge and attitudes towards disease risk are variable and can be improved. Producer knowledge of how persistently infected (PI) animals are produced was higher than that of disease outcomes or transmission pathways. Implementation of biosecurity practices was limited, with approximately half of respondents employing quarantine procedures for introduced stock and only 2% indicating they would antigen test introduced stock for BVDV. Approximately a third (36%) of producers reported engaging in BVDV control, with the majority of these using vaccination strategies over deliberate exposure to a PI. Knowledge of and engagement with BVDV control was positively influenced by the producer relationships with veterinarians. Findings from this study suggest that building on education and delivering a consistent message among stakeholders would likely improve producer awareness and understanding in relation to BVDV and support decision making in BVDV management.

From Beef to Bees: High-Throughput Kinome Analysis to Understand Host Responses of Livestock Species to Infectious Diseases and Industry-Associated Stress

Within human health research, the remarkable utility of kinase inhibitors as therapeutics has motivated efforts to understand biology at the level of global cellular kinase activity (the kinome). In contrast, the diminished potential for using kinase inhibitors in food animals has dampened efforts to translate this research approach to livestock species. This, in our opinion, was a lost opportunity for livestock researchers given the unique potential of kinome analysis to offer insight into complex biology. To remedy this situation, our lab developed user-friendly, cost-effective approaches for kinome analysis that can be readily incorporated into most research programs but with a specific priority to enable the technology to livestock researchers. These contributions include the development of custom software programs for the creation of species-specific kinome arrays as well as comprehensive deconvolution and analysis of kinome array data. Presented in this review are examples of the application of kinome analysis to highlight the utility of the technology to further our understanding of two key complex biological events of priority to the livestock industry: host immune responses to infectious diseases and animal stress responses. These advances and examples of application aim to provide both mechanisms and motivation for researchers, particularly livestock researchers, to incorporate kinome analysis into their research programs.

Modulation of Toll-like receptor-mediated innate immunity in bovine intestinal epithelial cells by lactic acid bacteria isolated from feedlot cattle

The ability of lactobacilli isolated from feedlot cattle environment to differentially modulate the innate immune response triggered by Toll-like receptors (TLRs) activation in bovine intestinal epithelial (BIE) cells was evaluated. BIE cells were stimulated with Lactobacillus mucosae CRL2069, Lactobacillus acidophilus CRL2074, Lactobacillus fermentum CRL2085 or Lactobacillus rhamnosus CRL2084 and challenged with heat-stable pathogen associated molecular patterns (PAMPs) from enterotoxigenic Escherichia coli (ETEC) to induce the activation of TLR4 or with polyinosinic:polycytidylic acid (poly(I:C)) to activate TLR3. Type I interferons, cytokines, chemokines and negative regulators of TLR signalling were studied by RT-PCR. L. mucosae CRL2069 significantly reduced the expression of interleukin (IL)-8 and monocyte chemoattractant protein (MCP)-1 in BIE cells in the context of TLR3 activation. L. mucosae CRL2069 also reduced the expression of tumour necrosis factor-α, IL-β, MCP-1, and IL-8 in heat-stable ETEC PAMPs-challenged BIE cells. In addition, reduced expressions of IL-6, MCP-1, and IL-8 were found in BIE cells stimulated with L. rhamnosus CRL2084, although its effect was significantly lower than that observed for the CRL2069 strain. The reduced levels of pro-inflammatory factors in BIE cells induced by the CRL2069 and CRL2085 strains was related to their ability of increasing the expression of TLR negative regulators. L. mucosae CRL2069 significantly improved the expression of A20-binding inhibitor of NFκ-B activation 3 (ABIN-3), interleukin-1 receptor-associated kinase M (IRAK-M) and mitogen-activated protein kinase 1 (MKP-1) while L. rhamnosus CRL2084 augmented ABIN-3 expression in BIE cells. The results of this work suggest that among the studied strains, L. mucosae CRL2069 was able to regulate TLR3-mediated innate immune response and showed a remarkable capacity to modulate TLR4-mediated inflammation in BIE cells. The CRL2069 strain induce the up-regulation of three TLR negative regulators that would influence nuclear factor kB and mitogen-activated protein kinases signalling pathways while reducing the expression of pro-inflammatory cytokines and chemokines. Therefore, L. mucosae CRL2069 is an interesting immunobiotic candidate for the protection of the bovine host against TLR-mediated intestinal inflammatory damage.

Genetic Diversity of Bovine Pestiviruses Detected in Backyard Cattle Farms Between 2014 and 2019 in Henan Province, China

Bovine pestiviruses include Pestivirus A (BVDV-1), Pestivirus B (BVDV-2), and Pestivirus H, which was originally called HoBi-like pestivirus. We conducted an epidemiological investigation for pestiviruses circulating in backyard cattle farms in central China. RT-PCR assays and sequences analysis were conducted on 54 nasal swabs, 26 serum samples, and three lung samples from cattle with respiratory infections and identified 29 pestivirus strains, including 24 Pestivirus A and five Pestivirus H strains. Phylogenetic analysis based on partial 5'-UTR and Npro sequences showed that the genotypes of 24 Pestivirus A strains included Pestivirus A 1b (six isolates), Pestivirus A 1m (six isolates), Pestivirus A 1q (two isolates), Pestivirus A 1u (one isolates), and Pestivirus A 1o (nine isolates, a putative new sub-genotype). In addition, a single Pestivirus H agenotype included all five Pestivirus H strains. This study revealed extensive genetic variations within bovine pestivirus isolates derived from cattle in backyard farms in Central China, and this epidemiological information improves our understanding of the epidemics of bovine Pestiviruses, as well as will be useful in designing and evaluating diagnostic methods and developing more effective vaccines.

The Use of Meta-Analysis for the Measurement of Animal Disease Burden: Losses Due to Clinical Mastitis as an Example

The literature contains an extensive panel of studies focusing on the costs of animal diseases. The losses of an agriculture holding can be influenced by many factors since farming is a complex system and diseases are closely interrelated. Meta-analysis can be used to detect effects (i.e., change in clinical mastitis losses here) across studies and to identify factors that may influence those effects. This includes the external validity of the published study results with regard to the input parameters and the internal validity of the study, particularly how other diseases related to the target disease were accounted for. Mixed-effect meta-regressions were performed to estimate the mean clinical mastitis losses per case across the literature and to elucidate to what extent clinical mastitis losses are influenced by (i) general factors, such as etiology; (ii) the types of losses that contribute to the total mastitis losses; and (iii) prices. In total, 82 observations from nine studies were included in the meta-analysis to assess mean clinical mastitis losses per case. The multivariate meta-regression showed that etiology significantly influenced the clinical mastitis loss per case. The mean loss was determined to be €224 per case for all published etiologies. In detail, mean losses equalled €457 and €101 per case of clinical mastitis due to gram-negative and gram-positive bacteria, respectively, and €428 and €74 per case of clinical mastitis due to Escherichia coli and Staphylococcus aureus, respectively. Additionally, the mean loss obtained depended on whether diagnostic costs and reduced feed intake in cases of mastitis were included in the clinical mastitis loss calculation. The monetary values of labor cost, drug cost and culling cost, as well as treatment price (all included), significantly influenced the clinical mastitis losses per case. All other tested moderators were not associated with mastitis losses, highlighting the need for more standardized economic studies, for both methods and ways results are presented, and suggesting that the mastitis losses assessed in the literature cannot be extrapolated (limited external validity). Although meta-analyses are useful to overview the burden of diseases across studies, their ability to summarize extensive literature with various economic assessments is limited. These limitations in loss assessments also suggest the need to focus on management strategies rather than on pure monetary estimations of disease costs, at least for production diseases at the farm level.