Bovine Herpesvirus Type Research Articles

The alphaherpesvirus gE/gI glycoprotein complex and proteases jointly orchestrate invasion across the host's upper respiratory epithelial barrier.

Herpes simplex virus type 1 (HSV-1) infections are a worldwide issue. More than three billion people are infected with HSV-1 globally. Although most infections with HSV-1 occur subclinically, severe symptoms and complications are numerous and can be life-threatening. Complications include encephalitis and blindness. Recently, HSV-1 infections have been associated with the development of Alzheimer's Disease. To date, no effective vaccines against HSV-1 are on the market. Pseudorabies virus (PRV) and bovine herpesvirus type 1 (BoHV-1) are two alphaherpesviruses of major veterinary importance. Although efforts have been made to eradicate these viruses from livestock animals, clinical problems still occur, resulting in great economic losses for farmers. It is evident that new insights into the pathogenesis of alphaherpesviruses are needed, to develop effective treatments and novel preventive therapies.

First detection and impact of bovine herpesvirus type 4 on dairy cattle reproduction in Thailand

Background and Aim: Postpartum reproductive tract infections pose significant challenges to dairy farms, leading to economic losses due to reduced fertility associated with uterine inflammation. In veterinary practice, numerous research groups have explored the underlying causes of subfertility in cows, including surveying endemic viral infections related to endometritis in local areas. This study investigated bovine herpesvirus 4 (BoHV-4) infection in Thai dairy herds and assessed its impact on endometritis and subsequent reproductive outcomes. Materials and Methods: The present study analyzed BoHV-4 DNA in various samples, including milk, blood, and endometrial tissue, from 44 Holstein-Friesian cows 21–47 days postpartum across five dairy herds in Central Thailand. BoHV-4 glycoprotein B and thymidine kinase DNA sequences were detected using the polymerase chain reaction (PCR) and nested PCR, with sequence comparisons made to GenBank data for phylogenetic analysis. The endometritis status was diagnosed through vaginal mucus examination and endometrial cytology, with reproductive performance monitored up to the subsequent calving. Results: BoHV-4 DNA was identified in blood and endometrial tissues (15.91%) but not in milk samples. Phylogenetic analysis revealed that the local BoHV-4 strains are similar to those identified in Brazil and Japan. Notably, the presence of BoHV-4 was correlated with reduced postpartum reproductive performance, particularly extending the interval from calving to the first service. Conclusion: Our findings underscore the importance of integrating BoHV-4 genomic surveys and uterine health assessments to refine reproductive management strategies within the dairy industry. Keywords: bovine herpesvirus-4, dairy cattle, endometritis, phylogenetic analysis, reproductive performance, Thailand.

Bovine Transcription Factor POU Class 2 Homeobox 1 (POU2F1/Oct1) Protein Promotes BoHV-1 Replication in MDBK Cells.

Bovine herpesvirus type 1 (BoHV-1) causes severe diseases in bovine species and great economic burden to the cattle industry worldwide. Due to its complex life cycle, many host factors that affect BoHV-1 replication remain to be explored. To understand the possible roles that the Oct1 cellular protein could play in this process, we first created Oct1-deficient MDBK cells using CRISPR/Cas9-mediated genome editing. Upon infection, the absence of Oct1 in MDBK cells significantly impacted BoHV-1 replication, a phenotype rescued by over-expressing the wild-type Oct1 protein in the deficient cells. We further found that the expression of all three classes of temporal genes, including essential and non-essential viral genes, were significantly reduced in Oct1 knockout MDBK cells, following both high and low multiplicity of infection. In summary, our findings confirm that the bovine Oct1 protein acts as a pro-viral factor for BoHV-1 replication by promoting its viral gene transcription in MDBK cells.

A Quadruple Gene-Deleted Live BoHV-1 Subunit RVFV Vaccine Vector Reactivates from Latency and Replicates in the TG Neurons of Calves but Is Not Transported to and Shed from Nasal Mucosa.

Bovine herpesvirus type 1 (BoHV-1) establishes lifelong latency in trigeminal ganglionic (TG) neurons following intranasal and ocular infection in cattle. Periodically, the latent virus reactivates in the TG due to stress and is transported anterogradely to nerve endings in the nasal epithelium, where the virus replicates and sheds. Consequently, BoHV-1 is transmitted to susceptible animals and maintained in the cattle population. Modified live BoHV-1 vaccine strains (BoHV-1 MLV) also have a similar latency reactivation. Therefore, they circulate and are maintained in cattle herds. Additionally, they can regain virulence and cause vaccine outbreaks because they mutate and recombine with other circulating field wild-type (wt) strains. Recently, we constructed a BoHV-1 quadruple mutant virus (BoHV-1qmv) that lacks immune evasive properties due to UL49.5 and glycoprotein G (gG) deletions. In addition, it also lacks the gE cytoplasmic tail (gE CT) and Us9 gene sequences designed to make it safe, increase its vaccine efficacy against BoHV-1, and restrict its anterograde neuronal transport noted above. Further, we engineered the BoHV-1qmv-vector to serve as a subunit vaccine against the Rift Valley fever virus (BoHV-1qmv Sub-RVFV) (doi: 10.3390/v15112183). In this study, we determined the latency reactivation and nasal virus shedding properties of BoHV-1qmv (vector) and BoHV-1qmv-vectored subunit RVFV (BoHV-1qmv sub-RVFV) vaccine virus in calves in comparison to the BoHV-1 wild-type (wt) following intranasal inoculation. The real-time PCR results showed that BoHV-1 wt- but not the BoHV-1qmv vector- and BoHV-1qmv Sub-RVFV-inoculated calves shed virus in the nose following dexamethasone-induced latency reactivation; however, like the BoHV-1 wt, both the BoHV-1qmv vector and BoHV-1qmv Sub-RVFV viruses established latency, were reactivated, and replicated in the TG neurons. These results are consistent with the anterograde neurotransport function of the gE CT and Us9 sequences, which are deleted in the BoHV-1qmv and BoHV-1qmv Sub-RVFV.

Investigation of the safety and protective efficacy of an attenuated and marker M. bovis-BoHV-1 combined vaccine in bovines.

Bovine respiratory disease (BRD) is one of the most common diseases in the cattle industry worldwide; it is caused by multiple bacterial or viral coinfections, of which Mycoplasma bovis (M. bovis) and bovine herpesvirus type 1 (BoHV-1) are the most notable pathogens. Although live vaccines have demonstrated better efficacy against BRD induced by both pathogens, there are no combined live and marker vaccines. Therefore, we developed an attenuated and marker M. bovis-BoHV-1 combined vaccine based on the M. bovis HB150 and BoHV-1 gG-/tk- strain previously constructed in our lab and evaluated in rabbits. This study aimed to further evaluate its safety and protective efficacy in cattle using different antigen ratios. After immunization, all vaccinated cattle had a normal rectal temperature and mental status without respiratory symptoms. CD4+, CD8+, and CD19+ cells significantly increased in immunized cattle and induced higher humoral and cellular immune responses, and the expression of key cytokines such as IL-4, IL-12, TNF-α, and IFN-γ can be promoted after vaccination. The 1.0× 108 CFU of M. bovis HB150 and 1.0 × 106 TCID50 BoHV-1 gG-/tk- combined strain elicited the most antibodies while significantly increasing IgG and cellular immunity after challenge. In conclusion, the M. bovis HB150 and BoHV-1 gG-/tk- combined strain was clinically safe and protective in calves; the mix of 1.0 × 108 CFU of M. bovis HB150 and 1.0 × 106 TCID50 BoHV-1 gG-/tk- strain was most promising due to its low amount of shedding and highest humoral and cellular immune responses compared with others. This study introduces an M. bovis-BoHV-1 combined vaccine for application in the cattle industry.

Investigation of the Optimal Immunization Dose and Protective Efficacy of an Attenuated and Marker M. bovis-Bovine Herpesvirus Type 1 Combined Vaccine in Rabbits.

Bovine respiratory disease (BRD) is one of the most common diseases in the cattle industry; it is a globally prevalent multifactorial infection primarily caused by viral and bacterial coinfections. In China, Mycoplasma bovis (M. bovis) and bovine herpesvirus type 1 (BoHV-1) are the most notable pathogens associated with BRD. Our previous study attempted to combine the two vaccines and conducted a preliminary investigation of their optimal antigenic ratios. Based on this premise, the research extended its investigation by administering varying vaccine doses in a rabbit model to identify the most effective immunization dosage. After immunization, all rabbits in other immunization dose groups had a normal rectal temperature without obvious clinical symptoms. Furthermore, assays performed on the samples collected from immunized rabbits indicated that there were increased humoral and cellular immunological reactions. Moreover, the histological analysis of the lungs showed that immunized rabbits had more intact lung tissue than their unimmunized counterparts after the challenge. Additionally, there appears to be a positive correlation between the protective efficacy and the immunization dose. In conclusion, the different immunization doses of the attenuated and marker M. bovis HB150 and BoHV-1 gG-/tk- combined vaccine were clinically safe in rabbits; the mix of 2.0 × 108 CFU of M. bovis HB150 and 2.0 × 106 TCID50 BoHV-1 gG-/tk- strain was most promising due to its highest humoral and cellular immune responses and a more complete morphology of the lung tissue compared with others. These findings determined the optimal immunization dose of the attenuated and marker M. bovis HB150 and BoHV-1 gG-/tk- combined vaccine, laying a foundation for its clinical application.

Investigation into the safety, and serological responses elicited by delivery of live intranasal vaccines for bovine herpes virus type 1, bovine respiratory syncytial virus, and parainfluenza type 3 in pre-weaned calves.

Despite the fact that pneumonia remains a leading cause of mortality and morbidity in pre-weaned calves, relatively little is known regarding the effects of the concurrent administration of intranasal pneumonia virus vaccines, particularly in calves with high levels of maternally derived antibodies. The objective of this study was to use a cohort of 40 dairy and dairy-beef female and male calves (27 females and 13 males) to determine serological responses to concurrent administration at 3 weeks of age (22 ± 4.85 days) of two commercially available intranasal (IN) vaccines for the viruses: bovine respiratory syncytial virus (BRSV), bovine herpes virus 1 (BoHV-1), and parainfluenza-3-virus (PI3-V). The study groups were as follows: (i) Bovilis IBR Marker Live only® (IO), (ii) Bovilis INtranasal RSP Live® only (RPO), (iii) Concurrent vaccination with Bovilis IBR Marker Live® & Bovilis Intranasal RSP Live® (CV), and (iv) a control group of non-vaccinated calves (CONT). The calves' serological response post-IN vaccination, clinical health scores, rectal temperatures, and weights were measured. Data were analyzed in SAS using mixed models and logistic regression. The CV calves had an average daily weight gain (ADG) of 0.74 (±0.02) kg, which was similar to CONT (0.77 ± 0.02 kg). Despite no significant differences in the antibody levels between study groups 3 weeks post-IN vaccination, following the administration of subsequent parenteral injections in the form of Bovilis Bovipast RSP®(antigens; inactivated BRSV, inactivated PI3-V, inactivated Mannheimia haemolytica) and Bovilis IBR Marker Live®, the antibody levels of the BRSV and PI3-V increased in both the CV and RPO study groups. Concurrent vaccination resulted in no increase in fever and no difference in health scores when compared to CONT.

Validation of Candidate Host Cell Entry Factors for Bovine Herpes Virus Type-1 Based on a Genome-Wide CRISPR Knockout Screen.

To identify host factors that affect Bovine Herpes Virus Type 1 (BoHV-1) infection we previously applied a genome wide CRISPR knockout screen targeting all bovine protein coding genes. By doing so we compiled a list of both pro-viral and anti-viral proteins involved in BoHV-1 replication. Here we provide further analysis of those that are potentially involved in viral entry into the host cell. We first generated single cell knockout clones deficient in some of the candidate genes for validation. We provide evidence that Polio Virus Receptor-related protein (PVRL2) serves as a receptor for BoHV-1, mediating more efficient entry than the previously identified Polio Virus Receptor (PVR). By knocking out two enzymes that catalyze HSPG chain elongation, HST2ST1 and GLCE, we further demonstrate the significance of HSPG in BoHV-1 entry. Another intriguing cluster of candidate genes, COG1, COG2 and COG4-7 encode six subunits of the Conserved Oligomeric Golgi (COG) complex. MDBK cells lacking COG6 produced fewer but bigger plaques compared to control cells, suggesting more efficient release of newly produced virions from these COG6 knockout cells, due to impaired HSPG biosynthesis. We further observed that viruses produced by the COG6 knockout cells consist of protein(s) with reduced N-glycosylation, potentially explaining their lower infectivity. To facilitate candidate validation, we also detailed a one-step multiplex CRISPR interference (CRISPRi) system, an orthogonal method to KO that enables quick and simultaneous deployment of three CRISPRs for efficient gene inactivation. Using CRISPR3i, we verified eight candidates that have been implicated in the synthesis of surface heparan sulfate proteoglycans (HSPGs). In summary, our experiments confirmed the two receptors PVR and PVRL2 for BoHV-1 entry into the host cell and other factors that affect this process, likely through the direct or indirect roles they play during HSPG synthesis and glycosylation of viral proteins.

Resposta anamnéstica contra o vírus da diarreia viral bovina e herpesvírus bovino tipo 1 em novilhas Holandesas jovens vacinadas com quatro diferentes formulações comerciais

ABSTRACT: This study evaluated the vaccine-induced serological response after administering four commercial formulations containing Bovine Viral Diarrhea Virus (BVDV) type-1, BVDV-2, and Bovine Herpesvirus type 1 (BoHV-1) to young heifers with circulating maternal antibody titers. The study also determined the anamnestic response to vaccinations after the complete metabolization of maternal antibodies when the calves reached six months. Eighty-seven Holstein heifers were selected and randomly distributed into four experimental groups based on the vaccine administered. The four vaccine-based experimental groups were as follows: vaccine A (n = 22), vaccine B (n = 22), vaccine C (n = 24), and vaccine D (n = 19), given on the 60th, 90th, and 180th day of life, respectively. Virus-neutralization (VN) tests were performed at baseline (day 60) and 30 days after administering the second (day 120) and third doses (day 210). We analyzed the effect of vaccine group (P ≤ 0.001), day of vaccination (P ≤ 0.001), and group versus vaccine day interaction (P ≤ 0.001) for antibody titers produced against BVDV-1, BVDV-2, and BoHV-1 using the PROC MIXED method (Statistical Analysis System -SAS 9.4). Antibody titers against BVDV-1, BVDV-2, and BoHV-1 were similar at baseline and on day 60 of life. The mean antibody titers were constant and persisted against BVDV-1 in heifers immunized with vaccines A and C. Heifers immunized with vaccine A alone had a similar effect against BVDV-2. Regarding BoHV-1, the antibody titers decreased between days 60 and 210 in groups B, C, and D. The antibody titer for heifers in group A also decreased between days 60 and day 120, and an intense increase in titers was observed on day 210. After being immunized with formulations B, C, and D, the frequency of animals with titers above protective levels for BVDV-1, BVDV-2, and BoHV-1 was very low or null. Indicators of anamnestic response were observed in heifers vaccinated with formulation A only. Therefore, it can be concluded that passive immunity negatively interferes with antibody production after vaccination.

Infectious bovine rhinotracheitis: Unveiling the hidden threat to livestock productivity and global trade.

An infectious disease called infectious bovine rhinotracheitis (IBR) can lead to a number of disorders affecting cattle's respiratory system. The disease is caused by bovine alphaherpesvirus type 1 (BoAHV-1). Based on antigenic and genetic characteristics, BoAHV-1 strains are divided into subtypes 1.1, 1.2a, 1.2b, and 1.3. IBR is currently widespread throughout the world, with the exception of a few nations that have achieved eradication. The most significant characteristic of this illness is that, after a clinical or subclinical infection, the virus typically establishes a latent condition that can later be reactivated in the presence of stress, immunosuppressive conditions/substances, or other diseases. Primarily, the virus spreads by direct or indirect contact between animals. It may also be transmitted via the reproductive system, causing infectious balanoposthitis or vulvovaginitis. Most virus subtypes are associated with reproductive failure, such as fetal or embryonic resorption and abortions. The virus may also be transmitted through semen, which could lead to genital transfer. Bovine herpesvirus type 1 (BoHV-1) infection produces a variety of lesions. Lesion in the mucosal surface usually consists of white necrotic material. Regular methods for diagnosing BoHV-1 infections include isolation in cell culture, enzyme linked immunosorbent assay, virus neutralisation test, and methods based on identification of nucleic acids, like PCR. The interplay of several host, pathogen, environmental, and management factors affects the spread of IBR. Through its impacts on health and fitness, IBR can lead to production losses. In order to minimize the severity of clinical signs and stop the infection from spreading, the veterinarian may advise that sick or at-risk animals be placed under immediate isolation and vaccinated (such as intranasal vaccination, including the use of both killed and live attenuated virus vaccines) as soon as an IBR diagnosis is obtained.

An intrinsic network of polar interactions is responsible for binding of UL49.5 C-degron by the CRL2KLHDC3 ubiquitin ligase.

Bovine herpesvirus type 1 (BoHV-1) is a pathogen of cattle responsible for infectious bovine rhinotracheitis. The BoHV-1 UL49.5 is a transmembrane protein that binds to the transporter associated with antigen processing (TAP) and downregulates cell surface expression of the antigenic peptide complexes with the major histocompatibility complex class I (MHC-I). KLHDC3 is a kelch domain-containing protein 3 and a substrate receptor of a cullin2-RING (CRL2) E3 ubiquitin ligase. Recently, it has been identified that CRL2KLHDC3 is responsible for UL49.5-triggered TAP degradation via a C-degron pathway and the presence of the degron sequence does not lead to the degradation of UL49.5 itself. The molecular modeling of KLHDC3 in complexes with four UL49.5 C-terminal decapeptides (one native protein and three mutants) revealed their activity to be closely correlated with the conformation which they adopt in KLHDC3 binding cleft. To analyze the interaction between UL49.5 and KLHDC3 in detail, in this work a total of 3.6 μs long molecular dynamics simulations have been performed. The complete UL49.5-KLHDC3 complexes were embedded into the fully hydrated all-atom lipid membrane model with explicit water molecules. The network of polar interactions has been proposed to be responsible for the recognition and binding of the degron in KLHDC3. The interaction network within the binding pocket appeared to be very similar between two CRL2 substrate receptors: KLHDC3 and KLHDC2.

GARP and EARP are required for efficient BoHV-1 replication as identified by a genome wide CRISPR knockout screen.

The advances in gene editing bring unprecedented opportunities in high throughput functional genomics to animal research. Here we describe a genome wide CRISPR knockout library, btCRISPRko.v1, targeting all protein coding genes in the cattle genome. Using it, we conducted genome wide screens during Bovine Herpes Virus type 1 (BoHV-1) replication and compiled a list of pro-viral and anti-viral candidates. These candidates might influence multiple aspects of BoHV-1 biology such as viral entry, genome replication and transcription, viral protein trafficking and virion maturation in the cytoplasm. Some of the most intriguing examples are VPS51, VPS52 and VPS53 that code for subunits of two membrane tethering complexes, the endosome-associated recycling protein (EARP) complex and the Golgi-associated retrograde protein (GARP) complex. These complexes mediate endosomal recycling and retrograde trafficking to the trans Golgi Network (TGN). Simultaneous loss of both complexes in MDBKs resulted in greatly reduced production of infectious BoHV-1 virions. We also found that viruses released by these deficient cells severely lack VP8, the most abundant tegument protein of BoHV-1 that are crucial for its virulence. In combination with previous reports, our data suggest vital roles GARP and EARP play during viral protein packaging and capsid re-envelopment in the cytoplasm. It also contributes to evidence that both the TGN and the recycling endosomes are recruited in this process, mediated by these complexes. The btCRISPRko.v1 library generated here has been controlled for quality and shown to be effective in host gene discovery. We hope it will facilitate efforts in the study of other pathogens and various aspects of cell biology in cattle.

Comprehensive diagnosis of abortion in cattle

Abstract. Abortion is one of the most common factors that has an extremely negative eff ect on the reproductive capacity of cattle, resulting in signifi cant economic losses. Abortions can be caused by infectious and non-infectious agents. Diagnosis of abortion is a diffi cult task, since only about 40% of abortions are diagnosed as infectious, and the remaining 60% - as unknown etiology. The goal was to establish the infectious etiology of abortion using complex diagnostics. The research was carried out in the laboratories of "Center of Veterinary Diagnostics" LLC (Kyiv). The selection of samples for research was carried out in the section hall of the LLC "Center of Veterinary Diagnostics" during the autopsy. The material for the study was a fetus and a vaginal smear from an aborted cow. Abortion occurred at 4 months of pregnancy. To establish the etiology, the following research methods were used: patho-anatomical, bacteriological, histological and molecular genetic (PCR-RT). Autolysis, light gray foci ≤ 2 mm in diameter in the lungs, and multiple light gray foci ≤ 1 mm in diameter in the liver were the main pathological fi ndings. The main pathohistological changes detected were focal myocarditis, intranuclear inclusion bodies in hepatocytes, multifocal coagulation necrosis in the lungs and liver, and diff use interstitial nephritis. Bacteriological culture was negative. DNA of infectious bovine rhinotracheitis virus (IBRV) and DNA of bovine herpesvirus type 4 (BHV-4) was isolated from the examined samples of fetal tissues and vaginal smear by PCR-RT. Using a comprehensive study, infectious agents and changes characteristic of the infectious process were identifi ed. On the basis of the obtained results, the etiology of the abortion was established as co-infection of IBRV and BHV-4. Complex diagnostics provides an opportunity to establish a cause-and-eff ect relationship between the identifi ed infectious agent and pathological changes in the fetus and the etiology of abortion. The results of a set of studies provide information on the manifestation of herpesvirus co-infection and complement the existing knowledge that can be used in the diagnosis of abortions in cows. Key words: abortion, cattle, IBRV, BHV-4, coinfection, PCR-RT, pathohistology, diagnosis.

The Safety and Protective Efficacy Evaluation of an Attenuated M. bovis-BoHV-1 Bivalent Vaccine in Rabbits.

Bovine respiratory disease (BRD) is a global prevalent multifactorial infection primarily caused by viral and bacterial coinfections. In China, Mycoplasma bovis (M. bovis) and bovine herpesvirus type 1 (BoHV-1) are the predominant pathogens associated with BRD. Our previous study involved the development of attenuated M. bovis HB150 and BoHV-1 gG-/tk- vaccine strains, which were thoroughly assessed for their safety profiles and protective efficacy in cattle. In this study, we applied a combination of vaccines in varying ratios and used a rabbit model to determine the safety and protective efficacy. We used PCR/RT-PCR to detect the postimmunization and challenge shedding of M. bovis and BoHV-1. Additionally, we measured antibody titers and the expression of IFN-β and TNF-α to evaluate the humoral and cellular immune responses, respectively. Furthermore, we performed a histopathological analysis to assess lung damage. Our study provides evidence of the safety and effectiveness of the bivalent M. bovis-BoHV-1 vaccine in rabbits, particularly when applying a combination of 1.0 × 108 CFU of M. bovis HB150 and 1.0 × 106 TCID50 of the BoHV-1 gG-/tk- strain. The bivalent vaccine significantly enhanced both the long-term antibody immune response and cellular protection against the M. bovis and BoHV-1 challenge. These findings provide a valuable model for the potential application in cattle.

Total and pathogen-specific serum Immunoglobulin G concentrations in neonatal beef calves, Part 1: Risk factors.

Maternal antibodies, delivered to the calf via colostrum, are crucial to prevent calfhood diseases and death. However, knowledge regarding the factors influencing this transfer of total and specific Immunoglobulin G (IgG) against common enteric and respiratory disease pathogens under current production conditions is sparse. The objectives of this study were to determine risk factors influencing total and pathogen-specific immunoglobulin G (IgG) concentrations against Escherichia coli (E. coli), bovine Rotavirus (BRoV), Cryptosporidium parvum (C. parvum), Bovine Viral Diarrhea Virus type 1 and 2 (BVDV), Parainfluenza Virus Type 3 (PI-3), Bovine Respiratory Syncytial Virus (BRSV), and Bovine Herpesvirus type 1 (BHV-1) in the serum of newborn beef calves. A total of 420 serum samples were collected from 1- to 7-day-old beef calves born on 6 farms in Alberta, Canada. Samples were analyzed by radial immunodiffusion for total IgG concentration and by enzyme-linked immunosorbent assays for pathogen-specific IgG concentrations against E. coli, BRoV, C. parvum, BVDV, PI-3, BRSV, and BHV-1. Multivariable multilevel linear and logistic regression models were built to evaluate dam- and calf-level risk factors associated with total and pathogen-specific IgG concentrations, failed transfer of passive immunity (FTPI; serum IgG < 10g/L), and inadequate transfer of passive immunity (ITPI; serum IgG < 24g/L). Farm was included as a random effect in all models to account for clustering at the herd level. Of the 420 calves included in this study, 5% (n=20) and 18% (n=75) of calves had FTPI and ITPI, respectively. Receiving colostrum intervention (i.e., being fed colostrum or colostrum product by either bottle or tube) was the most consistent risk factor for low total IgG concentration and significantly increased the odds of FTPI (Odds ratio (OR): 6.1, 95% CI: 2.0-18.9) and ITPI (OR: 4.8, 95% CI: 2.1-10.8). Calves born to cows consistently had higher pathogen-specific IgG concentrations (P<0.0001), compared to calves born from heifers, and calves born to vaccinated dams had significantly higher BRoV, BVDV, and BHV-1-specific IgG concentrations. Interestingly, E.coli-specific IgG concentrations were associated with dam vaccination only in cows but not in heifers, which was likely due to differing vaccination strategies used. This study highlights the need to review and refine protocols with respect to dam vaccination and colostrum intervention on cow-calf operations.

Total and pathogen-specific serum Immunoglobulin G concentrations in neonatal beef calves, Part 2: Associations with health and growth.

The association of poor transfer of passive immunity (TPI) with negative health outcomes is extensively researched in dairy calves. However, few field studies have examined the effect of total and particularly pathogen-specific Immunoglobulin G (IgG) concentrations on pre-weaning health and growth of beef calves. Hence, the objective of this study was to determine the association of total and pathogen-specific IgG concentrations against selected pathogens associated with neonatal calf diarrhea (NCD) and bovine respiratory disease (BRD) and the odds of pre-weaning treatments, mortality, and the growth of newborn beef calves. A total of 420 serum samples from 1- to 7-day old beef calves born on 6 farms in Alberta, Canada, were available for this observational study. Serum samples were analyzed by radial immunodiffusion for total IgG concentration and by enzyme-linked immunosorbent assays for pathogen-specific IgG concentrations against Escherichia coli (E. coli), bovine Rotavirus (BRoV), Cryptosporidium parvum (C. parvum), Bovine Viral Diarrhea Virus (BVDV), Parainfluenza Virus Type 3 (PI-3), Bovine Respiratory Syncytial Virus (BRSV), and Bovine Herpesvirus Type 1 (BHV-1). Data about the individual dam- and calf-level risk factors, calf treatments, mortality, and birth and weaning weights were collected. Multivariable multilevel logistic and linear regression models were built to evaluate the association of total and pathogen-specific IgG concentrations with the odds of mortality and average daily gain (ADG), respectively, while their association with the odds of pre-weaning treatment was established by univariable logistic regression analysis. The odds of calves with IgG concentrations <10g/L of getting treated (OR 7.9, 95 % CI 2.7-23.7) and dying (OR: 18.5, 95 % CI: 3.7-93.4) were higher than for their counterparts (P<0.0001). Calves with IgG concentrations <24g/L also had higher odds of dying (OR: 10.1, 95 % CI: 2.6-40.2) and had lower ADG (-0.09kg, SE: 0.03, P<0.002) than calves with IgG concentrations ≥24g/L. Higher BVDV-specific IgG concentration was protective against mortality (OR: 0.97, 95 % CI: 0.96-0.99, P<0.001). This study highlights the negative association of inadequate TPI with health and growth of beef calves and thus, the need to refine protocols for dam vaccination and colostrum intervention in cow-calf operations to meet these higher IgG targets.

A Novel Quadruple Gene-Deleted BoHV-1-Vectored RVFV Subunit Vaccine Induces Humoral and Cell-Mediated Immune Response against Rift Valley Fever in Calves.

Rift Valley fever virus (RVFV) is considered to be a high biodefense priority based on its threat to livestock and its ability to cause human hemorrhagic fever. RVFV-infected livestock are also a significant risk factor for human infection by direct contact with contaminated blood, tissues, and aborted fetal materials. Therefore, livestock vaccination in the affected regions has the direct dual benefit and one-health approach of protecting the lives of millions of animals and eliminating the risk of severe and sometimes lethal human Rift Valley fever (RVF) disease. Recently, we have developed a bovine herpesvirus type 1 (BoHV-1) quadruple gene mutant virus (BoHV-1qmv) vector that lacks virulence and immunosuppressive properties due to the deletion of envelope proteins UL49.5, glycoprotein G (gG), gE cytoplasmic tail, and US9 coding sequences. In the current study, we engineered the BoHV-1qmv further by incorporating a chimeric gene sequence to express a proteolytically cleavable polyprotein: RVFV envelope proteins Gn ectodomain sequence fused with bovine granulocyte-macrophage colony-stimulating factor (GMCSF) and Gc, resulting in a live BoHV-1qmv-vectored subunit vaccine against RVFV for livestock. In vitro, the resulting recombinant virus, BoHV-1qmv Sub-RVFV, was replicated in cell culture with high titers. The chimeric Gn-GMCSF and Gc proteins expressed by the vaccine virus formed the Gn-Gc complex. In calves, the BoHV-1qmv Sub-RVFV vaccination was safe and induced moderate levels of the RVFV vaccine strain, MP12-specific neutralizing antibody titers. Additionally, the peripheral blood mononuclear cells from the vaccinated calves had six-fold increased levels of interferon-gamma transcription compared with that of the BoHV-1qmv (vector)-vaccinated calves when stimulated with heat-inactivated MP12 antigen in vitro. Based on these findings, we believe that a single dose of BoHV-1qmv Sub-RVFV vaccine generated a protective RVFV-MP12-specific humoral and cellular immune response. Therefore, the BoHV-1qmv sub-RVFV can potentially be a protective subunit vaccine for cattle against RVFV.

INFECTIOUS BOVINE RHINOTRACHEITIS: A BRIEF OVERVIEW

Infectious bovine rhinotracheitis (IBR) is a disease of viral etiology, the causative agent of which is a member of the herpesvirus family - bovine herpesvirus type 1 (BHV-1). The infection is widespread, and only some countries have been able to obtain the status of IBR -free territories. The main negative consequences affecting the country's economy are a decrease in the reproductive and productive properties of livestock, as well as the death of the animal. Clinical symptoms of the disease are fever, cough, abortion, conjunctivitis. Sources of infection are sick cattle, in whose secretions from mucous membranes, abortive materials, and exudates DNA of BHV-1 can be detected. The virion, upon penetration into target tissues, rapidly replicates, causing lysis of infected cells. The genome of the virus encodes about 70 proteins, some of which can prevent the detection of infected cells by T cells, and the spread of infection into a latent form completely complicates the situation with IBR. Due to the fact that the virus is characterized by reactivation when the animal is under stressful conditions, continuous circulation of the pathogen among the herd is inevitable. Various commercial diagnostic tests based on serology and genetic engineering methods are used to diagnose BHV-1. In order to prevent IBR, animals are immunized with vaccines that are used in the pharmaceutical market. At the same time, research is being conducted to create new biological products that can protect cattle from disease.

Evidence of a Protein-Coding Gene Antisense to the UL5 Gene in Bovine Herpesvirus I.

Bovine herpesvirus type 1 (BoHV-1) is an important agricultural pathogen that infects cattle and other ruminants worldwide. Though it was first sequenced and annotated over twenty years ago, the Cooper strain, used in this study, was sequenced as recently as 2012 and is currently said to encode 72 unique proteins. However, tandem mass spectrometry has identified several peptides produced during active infection that align with the BoHV-1 genome in unannotated regions. One of these abundant peptides, "ORF M", aligned antisense to the DNA helicase/primase protein UL5. This study characterizes the novel transcript and its protein product and provides evidence to support the existence of homolog protein-coding genes in other Herpesviruses.

Association of different microbes and pathogenic factors in cases of infectious bovine keratoconjunctivitis in cattle from Eastern Kazakhstan.

Infectious bovine keratoconjunctivitis (IBK) causes a significant economic loss to cattle industries in many countries, including Kazakhstan. Although Moraxella bovis is recognized as an etiologic agent of IBK, other bacterial and viral agents have been suspected to play a role in the pathogenesis of this disease. This study aimed to evaluate samples collected from the eyes of IBK-affected cattle in Eastern Kazakhstan at different stages of IBK for the presence of Mor. bovis, Moraxella bovoculi, Mycoplasma bovis, Mycoplasma bovoculi, and Bovine Herpes Virus Type 1 (BHV-1) and to characterize Mor. bovoculi pilA gene sequence diversity from Mor. bovoculi positive samples. Individual ocular swabs (n = 168) were collected from cattle that had clinical signs of IBK during the summer of 2022 on farms in the Abay region of Kazakhstan. Eye lesion scores (1, 2, and 3) were assigned depending on the degree of ocular damage. Infectious bovine keratoconjunctivitis-associated organisms were detected using a multiplex real-time polymerase chain reaction assay. The Mor. bovoculi pilA gene was sequenced from Mor. bovoculi positive samples. Mycoplasma bovis and BHV-1 were not detected in any of the collected samples. Mycoplasma bovoculi was identified in the majority of samples overall, usually in mixed infection with Moraxella spp. Moraxella bovoculi was detected in 76.2% of animals and predominated in animals with eye lesion scores 2 and 3. Mycoplasma bovoculi was detected only in association with Mor. bovis and/or Mor. bovoculi in animals with eye lesion scores 2 and 3. Moraxella bovis was found in 57.7% of animals and was always identified in association with another organism. Sequencing of the pilA gene in 96 samples from Mor. bovoculi positive samples identified five PilA groups. The majority belonged to PilA group A. However, three new PilA groups were identified and designated PilA groups N, O, and P. The results indicate a high prevalence of Myc. bovoculi and Mor. bovoculi in eyes of cattle with IBK on livestock farms in Eastern Kazakhstan. Additional novel Mor. bovoculi PilA groups were identified.