Bovine Herpesvirus Research Articles

Seroprevalence and associated risk factors of bovine herpesvirus 1 in smallholder dairy farms in two districts of Gondar zones, North-West Ethiopia

Bovine herpesvirus 1 (BoHV-1) is the infectious agent that causes infectious bovine rhinotracheitis (IBR), a disease affecting the reproductive and respiratory systems of cattle. Significant economic losses result from infectious bovine rhinotracheitis because of metritis, abortions, placenta retention, recurrent breeding, animal deaths, and losses from trade restrictions. Reports of the diseases have been made in southern, southwestern and in major cities that kept improved breed of dairy cows in Ethiopia with prevalence ranging from 28.5–67 %. However, there is insufficient information available regarding the frequency and spread of IBR in the northwest part of the nation. In northwest Ethiopia, a cross-sectional study was carried out to estimate seroprevalence of BoHV-1 and identify associated risk factors. Dairy farms and farm owners were chosen using a multistage cluster sampling technique, while dairy cattle were chosen using a simple random sample technique. Four hundred and thirty-one dairy cattle from 177 herds in the Debark and Lay-Armachiho districts in the North and Central Gondar zones, respectively, both in Northwestern Ethiopia, were selected to provide serum samples. Owners of dairy animals provided information via questionnaires. Using a competitive enzyme-linked immunosorbent assay (c-ELISA), anti-BoHV-1 antibodies were detected in serum samples. To identify risk factors, univariable and multivariable mixed effect logistic regression models were used. We calculated animal level and herd level seroprevalence of 72 % (95 % CI: 64.9–78.4 %) and 85.7 % (95 % CI: 79.8–90 %), respectively. Parity was associated with seroprevalence of BoHV-1; cows with higher parity had increased seroprevalence of BoHV-1. Bull mating [OR=3.13, (95 % CI: 1.74–5.64)] compared to AI and Debark district [OR=2.73 (95 % CI: 1.63–4.57)] compared to Lay-Armachiho district, were associated with seroprevalence of BoHV-1. The study had shown that BoHV-1 is circulating out of the major cities and also on dairy farms keeping local breeds of dairy cows in Gondar zones, North-West Ethiopia. This suggests need of attention in prevention and control of BoHV-1.

Impact of bovine herpesvirus-1 infection on fertility in dairy cattle

Bovine herpesvirus-1 (BoHV-1) is endemic in the UK dairy herd and can have an important negative impact on fertility. As well as being the cause of infectious pustular vulvovaginitis and infectious balanoposthitis, BoHV-1 can reduce conception rate following introduction of the virus in contaminated semen at the time of artificial insemination. Its ability to cause abortions, particularly in the last trimester, is well-documented and the incidence of abortions can be high following the introduction of infection to naïve herds. The impact of BoHV-1 on herd fertility will depend on the degree of herd immunity, route of infection and strain of BoHV-1. Vaccination has been shown to reduce spread of BoHV-1 within and between herds, and to significantly reduce the risk of abortion. In light of the cost of a single abortion, and the impact of BoHV-1 on milk yield, routine vaccination against BoHV-1 offers a cost-effective control strategy suitable for most UK dairy herds.

Seroprevalence and Associated Risk Factors of Infectious Bovine Rhinotracheitis (IBR) and Animal Owners' Knowledge, Attitude and Practice (KAP) Towards the Disease in Selected Districts of East Wollega Zone, Oromia Regional State, Ethiopia.

Infectious bovine rhinotracheitis (IBR) is one of the most important diseases affecting production and productivity. Cross-sectional study was aimed at to determine the seroprevalence of IBR and associated risk factors, and animal owners' knowledge, attitude and practice towards the disease from April 2021 to June 2022. Accordingly, a total of 384 serum samples were collected from both crossbreed (70) and local breed (314) cattle from purposively selected districts of East Wollega zone of Western Ethiopia. Competitive enzyme-linked immunosorbent assay (ELISA) was used for testing glycoprotein antibodies (anti-gB) for bovine herpes virus-1 (BoHV-1) virus in collected serum, and the obtained data were analysed by multiple logistic regressions by using R software 3.62 version. However, questionnaire data were analysed for descriptive statistics by SPSS version 20.0 (IBM. Corp, 2011). The total prevalence of IBR in the study area was found to be 70.54% at herd and 80.47% at individual cattle level. The significant association (p ) was found for breed, age, body condition and herd size but not for district and sex as risk factors. The BoHV-1 virus seropositivity in adult animals increased significantly, with an odds ratio of 1.65 (95% CI 0.705-3.85) compared to young. Local breed cattle were 2.055 times more likely to test positive for IBR with an odds ratio of 0.77 (95% CI 0.23-2.22) compared to crossbreed cattle. The chances of cattle in medium herds testing positive for the BoHV-1 virus with an odds ratio of (1.78 95% CI 1.303-7.50) are greater than the chances of cattle in smaller herds testing positive. The survey results showed that 70% of animal owners identified IBR as a major challenge in animal production, whereas 35% mentioned long calving intervals. However, 92% of the participants were not informed about the level of knowledge and attitude regarding particular diseases such as IBR. This study showed that there is a high prevalence of IBR in cattle in the study area, and that owners have low awareness of the disease. Therefore, it is necessary to develop an immediate control system and conduct additional research on molecular detection to evaluate its effects on reproductive performance.

Stress Can Induce Bovine Alpha-Herpesvirus 1 (BoHV-1) Reactivation from Latency

Bovine alpha-herpesvirus 1 (BoHV-1) is a significant problem for the cattle industry, in part because the virus establishes latency, and stressful stimuli increase the incidence of reactivation from latency. Sensory neurons in trigeminal ganglia and unknown cells in pharyngeal tonsils are importantsites for latency. Reactivation from latency can lead to reproductive problems in pregnant cows, virus transmission to young calves, suppression of immune responses, and bacterial pneumonia. BoHV-1 is also a significant cofactor in bovine respiratory disease (BRD). Stress, as mimicked by the synthetic corticosteroid dexamethasone, reproducibly initiates reactivation from latency. Stress-mediated activation of the glucocorticoid receptor (GR) stimulates viral replication and transactivation of viral promoters that drive the expression of infected cell protein 0 (bICP0) and bICP4. Notably, GR and Krüppel-like factor 15 (KLF15) form a feed-forward transcription loop that cooperatively transactivates immediate early transcription unit 1 (IEtu1 promoter). Two pioneer transcription factors, GR and KLF4, cooperatively transactivate the bICP0 early promoter. Pioneer transcription factors bind silent viral heterochromatin, remodel chromatin, and activate gene expression. Thus, wepredict that these novel transcription factors mediate early stages of BoHV-1 reactivation from latency.

Cross-Reactive Immune Response of Bovine Coronavirus Spike Glycoprotein to SARS-CoV-2 Variants of Concern

The high variability observed in the clinical symptoms of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections has been attributed to the presence, in a proportion of infection-naive subjects, of pre-existing cross-reactive immune responses. Here, we demonstrate that the bovine coronavirus spike protein (BoS) may represent a source of protective immunity to SARS-CoV-2. Indeed, vaccination of BALB/c mice with a Bovine herpesvirus 4 (BoHV-4)-based vector expressing BoS induced both cell-mediated and humoral immune responses that cross-react with SARS-CoV-2 spike protein. Although the spike-specific antibodies induced by BoS did not neutralize SARS-CoV-2, the T lymphocytes activated by BoS were able to induce cytotoxicity of cells expressing spike proteins derived from several SARS-CoV-2 variants. These results demonstrate that immunization with BoS may represent a source of cross-reactive immunity to SARS-CoV-2, and that these cross-reactive immune responses may exert protective functions. These results contribute to deciphering the mechanisms responsible for lack or mildness of symptoms observed in many individuals upon SARS-CoV-2 infection and may open new ways for the development of new vaccines for coronaviruses.

Microbiological Profile of the Upper and Lower Respiratory Tract of Suckling and Weaned Dairy Calves with Acute Respiratory Disease

Bovine respiratory disease (BRD) is a significant global health issue in cattle farming, leading to substantial economic losses. This study analyzed the microbiological profiles of BRD outbreaks in nine dairy cattle herds in southern Brazil. We examined 36 biological samples, including 24 deep nasopharyngeal swabs (NS) and 12 lung tissue, from 29 suckling and 7 weaned heifer calves with acute BRD. PCR and RT-PCR techniques were used to partially amplify the genes of five viruses and four respiratory bacteria. A total of 8 different microorganisms, 4 viruses (bovine viral diarrhea virus, n = 5; bovine coronavirus, n = 3; bovine alphaherpesvirus 1, n = 3; and bovine parainfluenza virus 3, n = 2), and 4 bacteria (Pasteurella multocida, n = 16; Mycoplasma bovis, n = 8; Histophilus somni, n = 7; and Mannheimia haemolytica, n = 4) were identified in 29 (80.5%) samples. Seven samples (four lung tissue and three NS) were negative for all the microorganisms. Mixed infections were more common (62.1%) than single infections (37.9%). Bacterial nucleic acids were more commonly co-detected in NS than in lung tissue. Nucleic acids from a single pathogen were more frequently detected in lung tissues than in NS. M. bovis was the only bacterium detected in the lower respiratory tract. Understanding the microbiological profiles of the respiratory tracts of dairy calves with clinical signs of BRD is crucial for implementing effective biosecurity measures to prevent BRD in suckling and weaned dairy heifer calves.

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.

Assessing bull breeding soundness exam parameters following vaccination with modified-live or killed vaccine

Breeding bulls are often placed on a similar herd health plan and vaccinated for the same pathogens as the mature cow herd. The timing of the yearly vaccination is impacted by labor and time constraints with some bulls receiving vaccinations at the time of annual, complete breeding soundness exams or at the time of turnout prior to the breeding season. However, the potential impact of vaccination on spermatogenesis, if any, is unknown. Therefore, the study objective was to determine the impacts on normal sperm morphology through a complete spermatogenic cycle after vaccination of mature beef bulls against bovine herpesvirus 1 and bovine viral diarrhea virus using commercially available modified-live virus (MLV) or killed virus (KV) vaccine. Semen was collected from Bos taurus bulls (n = 11),which were randomly assigned prior to the first breeding soundness exam to vaccine treatment groups: 1) modified-live virus (MLVa); or 2) inactivated/killed virus (KVb). Breeding soundness exams were completed at days -7, 0, 5, 7, 17, 28, 61 following vaccination. No differences were found between vaccine treatment groups MLV and KV (P = 0.46) on the percentage of normal sperm over time (d = -7 through d = 61) as evaluated by two boarded theriogenologists. In conclusion, we found no detrimental effect of the administration of multivalent MLV or KV vaccines on percentage of normal sperm morphology of mature bulls over a 61 – day period.

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 broad-spectrum biological activities of Heracleum humile extracts: A first report of the antiviral, anti-cancer and chemical properties

The current work focused on researching the bioactive potential of ethyl acetate (EA), methanol (MeOH), and water extract of H. humile plant, specifically ethyl acetate, methanol extracts were acquired with maceration method, and water extract was obtained by the infusion method. The highest total phenolic ingredient was determined in the water extract, while the highest total flavonoid ingredient was found in the MeOH extract. The water extract displayed the most potent antioxidant activity in the assays used. The ethyl acetate extract showed the highest enzyme inhibition activity in Butyrylcholinesterase inhibition (BChE) and amylase assay. Antibacterial efficiency was analyzed using microdilution analysis. The minimum inhibitory concentration (MIC) amounts ranged from 125 to 500 μg/mL except for water extract. The antiviral potential of the extracts was assessed against Bovine herpes virus 1 (BoHV-1) (Cooper strain). Methanol extract showed more potent antiviral effect. Selectivity indices were calculated for ethyl acetate and methanol extract as 3.32 and 13.39, respectively. All extracts displayed Deoxyribonucleic Acid (DNA) protection activity at approximately 25%–35%. For cell viability evaluation, 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) test was performed against triple-negative human breast adenocarcinoma cells (MDA-MB-231) and Michigan Cancer Foundation-7 (MCF-7) cells. The most effective results were found in ethyl acetate extract at 48h. The 50% inhibitor concentrations (IC50) were determined for MDA-MB-231 and MCF-7 as 116.7 μg/mL and 247.9 μg/mL, respectively. Based on the bioactive compound content results, extracts of H. humile include valuable compounds that possess significant biological properties. In conclusion, these extracts could offer promising novel plant-derived therapeutics.

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.

Molecular Characterisation of US6 (gD) and US8 (gE) Glycoprotein Genes Located on a Unique Short Region of Bovine Alphaherpesvirus-1 (BoAHV-1) Genome

Background: Bovine alphaherpesvirus type 1 (BoAHV-1) is a significant pathogen causing respiratory diseases and reproductive issues in cattle and buffaloes, resulting in substantial economic losses globally. This study provides a comprehensive analysis of the genetic characteristics of BoAHV-1 isolates from India, focusing on glycoprotein genes US6 (gD) and US8(gE). Methods: Ten archival isolates that were stored at the ICAR-NIVEDI BSL-2 facility were chosen, revived on MDBK cell lines and subjected for molecular characterization through PCR amplification of partial US6 (gD) and US8 (gE) gene. Genome alignment and phylogenetic analysis were performed by GeneTool and Mega 11. Result: Phylogenetic analysis of both genes revealed two cluster formation, BoAHV-1.1, BoAHV-1.2 in one cluster and BoAHV-5, Bubaline alphaherpesvirus (BuAHV-1) in another cluster. All ten isolates displayed close relation to BoAH 1.1. Seven isolates from each phylogenetic analysis showed 100% genome identity to vaccine strains from USA- Bovishield Gold MLV, Pyramid IBR MLV, Switzerland Cooper strain, ATCC Los Angeles strain, previously reported BoAHV 1.1 strains of India and Egypt. Genome identity of BoAHV-1.1 against BoAHV-1.2 was 97.70 to 98.70% for gD gene and 99.0 to 99.70% for gE gene respectively. The analysis highlights the higher genome identity among BoAHV-1 subtypes in the gE gene, suggesting its potential for developing more sensitive immunoassays for seroepidemiology. The developed assay could also be exploited for detecting BoAHV-5 infections. The findings contribute to the knowledge base essential for development of companion ELISA for implementing Differentiating Infected from Vaccinated Animals (DIVA) vaccination strategies.

102 Combination and individual vaccines for bovine viral diarrhea virus and infectious bovine rhinotracheitis effects on reproductive cyclicity and immune response

Abstract Vaccines are known to impact both the immune and reproductive systems. The objective of this research was to identify immunological and cyclic differences following vaccination for Bovine Viral Diarrhea Virus (BVDV) and/or Infectious Bovine Rhinotracheitis (IBR). Brahman cows (n = 15) were administered PGF2α to regress corpus lutea on d -3. Animals (d 0) were immunized (2mL, intramuscular injection) with one of three treatments: 1) Modified Live Vaccine (MLV) for BVDV and IBR (BVD+IBR; n = 5), 2) MLV for BVDV only (BVD; n = 5), or 3) sterile saline (CON; n = 5). Blood samples (30 mL/cow) were collected (d -3, 0, 2, 4, 6, 8, 10, and 14) and peripheral blood mononuclear cells (PBMC) were isolated. PBMC were incubated with propidium iodide and antibodies for specific surface cell markers (CD4, CD8, CD25, CD14, CD86, and CD335). An Amnis FlowSight flow cytometer determined cell type percentage. BVDV and IBR antibody concentrations were analyzed in serum samples (d -3, 0, and 14). Plasma samples (d 0, 2, 4, 6, 8, 10, and 14) were evaluated for interferon (IFN)-γ, interleukin (IL)-1α, IL-1β, IL-4, IL-6, IL-8, IL-10, IL-17A, macrophage inflammatory protein (MIP)-1α, MIP-1β, IL-36RA, interferon-gamma-induced protein (IP)-10, monocyte chemoattractant protein (MCP)-1, tumor necrosis factor (TNF) α, and vascular endothelial growth factor (VEGF) A concentrations by a MagPix multiplex machine using a MILLIPLEX Bovine Cytokine/Chemokine Magnetic Bead Panel. Progesterone (d 0, 2, 4, 6, 8, 10, and 14) and estradiol (d 0) concentrations were determined by RIA. Differences in antibody titers, PBMC populations, and cytokine concentrations were analyzed as repeated measures using PROC MIXED (SASv9.4). Forty percent of BVD+IBR animals experienced abnormal estrus cycles, but no BVD or CON animals did. There was a treatment effect on BVD titer concentration with BVD animals having greater titer concentrations than CON (P = 0.02) but similar concentrations to BVD+IBR (P = 0.18). There was a treatment by time interaction (P < 0.0001) on IBR titers with BVD+IBR animals having greater titer concentrations on d 14 compared with BVD and CON. Treatment had no effect on leukocyte populations (P ≥ 0.1409), but all populations differed over time (P ≤ 0.0045). Antigen presenting cells (CD14+) and natural killer cells (CD335+) were affected by a treatment and time interaction (P ≤ 0.0479). BVD animals had increased CD14+ cells on d 2, 4, 8, and 14 compared with CON, but CON had a greater CD335+ cell population compared with BVD and BVD+IBR on d 10. There tended to be or was a significant treatment by day interaction for IL-1α (P = 0.08), IL-1b (P = 0.03), IL-10 (P = 0.06), IFN-γ (P = 0.05), IP-10 (P = 0.02), MIP-1α (P = 0.02), MIP-1 b (P = 0.01), TNFα (P = 0.01), and VEGFA (P = 0.03). IL-1a, IL-10, IL-1b, and MIP-1 b increased in BVD+IBR from d 0 to 4 or 6 then decreased but not in CON or BVD. Increased VEGFA was observed in CON compared with BVD and BVD+IBR animals. Overall, BVD+IBR resulted in abnormal cycles and changes in cytokine concentrations and leukocyte populations. USDA is an equal opportunity provider and employer.

Enhanced immune response with baculovirus-expressed BoHV-1 glycoprotein D in vaccine development

Bovine herpesvirus 1 (BoHV-1), a significant pathogen in the alpha-herpesvirus subfamily, primarily infects cattle and causes the upper respiratory disease known as infectious bovine rhinotracheitis (IBR). In silico studies evaluated the BoHV-1 D protein to be non-allergenic, non-toxic, and highly antigenic, highlighting its potential as an antigen for vaccine development. Therefore, this study aimed to evaluate the efficacy of a subunit vaccine using the ectodomain of glycoprotein D (gD34–380) as an antigen. The truncated gD was successfully cloned and expressed in both Escherichia coli (E. coli, termed EgD) and baculovirus (termed BgD) systems, with expected molecular weights of 65 kDa and 50 kDa, respectively. For the vaccine formulation, the gD proteins were used either alone or in combination with in-house inactivated BoHV-1. Vaccination of mice and bovines showed that baculovirus-expressed gD34–380 accelerated the antibody response. Moreover, the BgD-vaccinated group also showed significantly higher neutralizing antibody levels against BoHV-1 than the control group (p<0.0001). In conclusion, our study found that BgD from BoHV-1 can increase the immune response and enhance vaccine efficacy.

Research progress on the structure and function of the main glycoproteins of bovine infectious rhinotracheitis virus

Research progress on the structure and function of the main glycoproteins of bovine infectious rhinotracheitis virus

482 Using growth implants in suckling beef calves enhanced vaccine response against Infectious Bovine Rhinotracheitis

482 Using growth implants in suckling beef calves enhanced vaccine response against Infectious Bovine Rhinotracheitis

Transcriptomic analysis reveals bovine herpesvirus 1 infection regulates innate immune response resulted in restricted viral replication in neuronal cells

BackgroundBovine herpesvirus 1 (BoHV-1) is a major pathogen that affects the global bovine population, primarily inducing respiratory and reproductive disorders. Its ability to establish latent infections in neuronal cells and to reactivate under certain conditions poses a continual threat to uninfected hosts. In this study, we aimed to analyze the replication characteristics of BoHV-1 in neuronal cells, as well as the effects of viral replication on host cell immunity and physiology. MethodsUsing the Neuro-2a neuronal-origin cell line as a model, we explored the dynamics of BoHV-1 replication and analyzed differential gene expression profiles post-BoHV-1 infection using high-throughput RNA sequencing. ResultsBoHV-1 demonstrated restricted replication in Neuro-2a cells. BoHV-1 induced apoptotic pathways and enhanced the transcription of interferon-stimulated genes and interferon regulatory factors while suppressing the complement cascade in Neuro-2a cells. ConclusionsDifferent from BoHV-1 infection in other non-highly differentiated somatic cells result in viral dominance, BoHV-1 regulated the innate immune response in neuronal cells formed a “virus-nerve cell” relative equilibrium state, which may account for the restricted replication of BoHV-1 in neuronal cells, leading to a latent infection. These findings provide a foundation for further research into the mechanism underlying BoHV-1-induced latent infection in nerve cells.

An outbreak of ischaemic teat necrosis in a dairy herd in Taranaki, New Zealand

ABSTRACT Case History In spring 2021, on a seasonally calving, pastorally based, Taranaki dairy farm, 12 first-calving heifers (≤ 30 days post-calving) developed similar dry, red to black, crusting lesions on the medial aspect of the teat udder junction extending down the medial teat. Some cows had multiple teats affected. Treatment was initially unrewarding and did not slow the progression of the disease. Overall, 8/12 cows recovered, and 4/12 cows were culled, with three of the cows culled after a teat sloughed and the fourth after surgical amputation of a teat. Outbreaks of the same condition, on the same farm but affecting fewer animals, occurred in spring 2022 (n = 6) and spring 2023 (n = 3). Clinical Findings An initial scab-like or crusting lesion progressed to resemble a thick eschar consisting of very dry and hard dead tissue. The unaffected areas of the teat felt normal but immediately under the dead tissue, there was a warm, firmer area consistent with an inflammatory reaction. Removing the scab led to profuse bleeding, with no visible bed of granulation underneath the scab. There was no leaking of milk in those cows that lost a teat, and no smell to the lesions themselves. Serology and virology ruled out the involvement of bovine alphaherpesvirus (BoHV-2) bovine gammaherpesvirus (BoHV-4), orthopoxviruses (cowpox) and parapoxviruses (pseudocowpox). Histopathology of an affected and surgically amputated teat showed multifocal erosion and ulceration of the epidermis, covered by a thick serocellular crust. In areas of ulceration, there were numerous neutrophils, and the dermis was expanded by granulation tissue with variable numbers of neutrophils, eosinophils, and lymphocytes around small blood vessels. Diagnosis Based on the similarity of the history, presentation, and histopathological changes to those described for a novel disease reported in the UK, a diagnosis of ischaemic teat necrosis (ITN) was made. Clinical Relevance If ITN is an emerging condition in New Zealand and becomes as prevalent as it has in the UK, clinicians will be confronted with a significant new welfare problem in dairy cows. Anecdotally, there have been reports of other ITN outbreaks in New Zealand, and the Ministry for Primary Industries would be interested in collating reports from other New Zealand veterinarians.

Identification and phylogenetic analysis of bovine herpesvirus 4 isolated from aborted bovine foetuses in Türkiye.

Bovine herpesvirus 4 (BoHV-4) is responsible for reproductive disorders and abortions in cattle. The aim of this study was to investigate the potential role of BoHV-4 in abortions in dairy cows when the possible aetiological cause could not be determined in Türkiye. The study also provided the molecular characterization of BoHV-4 strains based on the gB gene. In this study, foetuses (n = 188) and serum (n = 50) were retrospectively used for PCR and indirect ELISA assays, respectively. In addition, foetuses with BoHV-4 were tested for the isolation of the BoHV-4 strain in MDBK cell culture. The BoHV-4 gB gene was detected in the brain, liver, lung, kidney, and spleen tissues of three foetuses out of 188 aborted foetuses. The BoHV-4 strain was isolated from the kidney of one foetus in MDBK cell culture. The three aborted foetuses were from different cows in the same herd in 2021. On this dairy farm, the BoHV-4 seroprevalence rate in cattle with a history of abortion was 96% (48/50). Phylogenetic analysis revealed that the detected strains belong to genotype II. The present study shows that the impact of BoHV-4 on abortions in cattle should not be ignored. It can therefore be informative to focus on BoHV-4 in routine laboratory diagnostics for abortions without a proven aetiology or in cattle herds that have previously been infected with BoHV-4.