Tegument protein UL3 of bovine herpesvirus 1 suppresses antiviral IFN-I signaling by targeting STING for autophagic degradation.

Bovine herpesvirus 1 (BoHV-1) is a highly contagious pathogen which causes infectious bovine rhinotracheitis in cattle worldwide. Although it has the ability to evade the host's antiviral innate immune response and establish persistent latent infections, the mechanisms are not fully understood, especially the function of the tegument protein to escape innate immunity and participate in viral replication. In this study, we showed that overexpression of tegument protein UL3 facilitates BoHV-1 replication and suppresses the expression of type-I interferon (IFN-I) and IFN-stimulated genes. Then, STING was identified as the target by which UL3 inhibits the IFN-I signaling pathway, and STING was degraded through the UL3-induced autophagy pathway. Furthermore, overexpression of UL3 promotes the expression of the autophagy-related protein ATG101, thereby inducing autophagy. Further study showed that UL3 enhances the interaction between ATG101 and STING, and then the degradation of STING was reversed following ATG101 silencing in UL3-overexpressing cells during BoHV-1 infection. Our research results demonstrate a novel function of UL3 in regulating host's antiviral response and provide a potential mechanism for BoHV-1 immune evasion.

Integrated analysis of microRNA and messenger RNA expression profiles reveals functional microRNA in infectious bovine rhinotracheitis virus-induced mitochondrial damage in Madin-Darby bovine kidney cells.

BACKGROUND: Studies have confirmed that Infectious bovine rhinotracheitis virus (IBRV) infection induces mitochondrial damage. MicroRNAs (miRNAs) are a class of noncoding RNA molecules, which are involved in various biological processes and pathological changes associated with mitochondrial damage. It is currently unclear whether miRNAs participate in IBRV-induced mitochondrial damage in Madin-Darby bovine kidney (MDBK) cells. RESULTS: In the present study, we used high-throughput sequencing technology, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis to screen for mitochondria-related miRNAs and messenger RNAs (mRNAs). In total, 279 differentially expressed miRNAs and 832 differentially expressed mRNAs were identified in 6 hours (IBRV1) versus 24 hours (IBRV2) after IBRV infection in MDBK cells. GO and KEGG enrichment analysis revealed that 42 differentially expressed mRNAs and 348 target genes of differentially expressed miRNAs were correlated with mitochondrial damage, and the miRNA-mitochondria-related target genes regulatory network was constructed to elucidate their potential regulatory relationships. Among the 10 differentially expressed miRNAs, 8 showed expression patterns consistent with the high-throughput sequencing results. Functional validation results showed that overexpression of miR-10a and miR-182 aggravated mitochondrial damage, while inhibition of miR-10a and miR-182 alleviated mitochondrial damage. CONCLUSIONS: This study not only revealed the expression changes of miRNAs and mRNAs in IBRV-infected MDBK cells, but also revealed possible biological regulatory relationship between them. MiR-10a and miR-182 may have the potential to be developed as biomarkers for the diagnosis and treatment of IBRV. Together, Together, these data and analyses provide additional insights into the roles of miRNA and mRNA in IBRV-induced mitochondria damage.

Application of CRISPR/Cas9 for Rapid Genome Editing of Pseudorabies Virus and Bovine Herpesvirus-1.

The CRISPR/Cas9 system is widely used to manipulate viral genomes. Although Alphaherpesvirinae genomes are large and complicated to edit, in recent years several Pseudorabies virus (PRV) mutants have been successfully generated using the CRISPR/Cas9 system. However, the application of CRISPR/Cas9 editing on another member of alpha herpesviruses, bovine herpesvirus-1 (BHV-1), is rarely reported. This paper reports a rapid and straightforward approach to manipulating herpesviruses genome using CRISPR/Cas9. The recombinant plasmids contained the left and right arm of the thymidine kinase (TK) gene of PRV or of the glycoprotein I (gI) and glycoprotein E (gE) of BHV-1. Upon the cleavage of the TK or gIgE gene by Cas9 protein, this was replaced by the enhanced green fluorescence protein (eGFP) by homologous recombination. With this approach, we generated recombinant TK-/eGFP+ PRV and gIgE-/eGFP+ BHV-1 mutants and then proceeded to characterize their biological activities in vitro and in vivo. In conclusion, we showed that alpha herpesvirus, including PRV and BHV-1, can be rapidly edited using the CRISPR/Cas9 approach paving the way to the development of animal herpesvirus vaccines.

Preliminary molecular study for DIVA trial of antigenically characterized circulating bovine herpesvirus subtype 1.1 in Egypt.

Using marker vaccines to control bovine alphaherpesvirus-1 (BoHV-1) is a novel strategy for differentiation between infected and vaccinated animals (DIVA). In this study, multiplex real-time PCR targeting gD and gE genes was applied for BoHV-1 screening on 60 clinical samples from cattle with a history of vaccination, in some cases by US2-deleted marker vaccines, that were suffering from severe respiratory symptoms. Conventional PCR targeting the gC and US2 flanking region was done for molecular characterization and identification of the US2-deleted vaccine strain. Six samples were positive for BoHV-1 by both RT-PCR and conventional PCR. Surprisingly, a conventional PCR DIVA trial based on the US2 gene revealed that only one sample that exhibited the US2 gene was a wild virus, while others that did not exhibit the US2 gene were vaccine viruses. Phylogenetic characterization classifies the samples as BoHV-1.1. This finding reveals the circulation of vaccine virus in field-diseased animals, which threatens the eradication program.

Carnitine palmitoyl-transferase 1A is potentially involved in bovine herpesvirus 1 productive infection.

Bovine herpesvirus 1(BoHV-1) is an important bovine pathogen that causes great economic loss to cattle farms worldwide. The virus-productive infection in bovine kidney (MDBK) cells results in ATP depletion. The mechanisms are not well understood. Mitochondrial fatty acid ß-oxidation (FAO) is an important energy source in many tissues with high energy demand. Since carnitine palmitoyl-transferase 1 A (CPT1A) is the rate-limiting enzyme of FAO, we investigated the interactions between virus-productive infection and CPT1A signaling. Here, we found that virus-productive infection at the later stage significantly decreased CPT1A protein levels in all the detected cells, including MDBK, A549, and Neuro-2A cells, differentially altered the accumulation of CPT1A proteins in the nucleus and cytosol, and re-localized the protein in the nucleus. Etomoxir (ETO), an irreversible inhibitor of CPT1A, inhibited viral replication and partially interfered with the ability of BoHV-1 to alter CPT1A accumulation in the nucleus but not in the cytosol. Furthermore, ETO consistently reduced RNA levels of two viral regulatory proteins (bICP0 and bICP22) and protein expression of virion-associated proteins during productive infection, further supporting the important roles of CPT1A signaling in BoHV-1 productive infection. These data, for the first time, suggest that CPT1A is potentially involved in BoHV-1 productive infection.

Bovine herpesvirus-1 gE protein inhibits IFN-ß production to enhance replication by promoting MAVS ubiquitination and interfering with the interaction between IRF3 and CBP/p300.

Bovine herpesvirus-1 (BoHV-1) can infect all breeds of cattle and cause respiratory and genital tract diseases. In the process of viral infection, viruses can use their own proteins to suppress the innate immunity of the host and promote its replication; however, the mechanism by which BoHV-1 evades the innate immune response is not fully understood. In this study, we found that rabbits inoculated with the live gene deletion vaccine BoHV-1-△gI/gE/TK generated higher interferon-ß (IFN-ß) production in the serum, liver, lung and kidney than rabbits inoculated with wt BoHV-1, which led to milder lesions in the lung and kidney. We performed gene deletion and ectopic expression experiments on viral proteins and found that gE was the major protein that inhibited IFN-ß expression. Further studies showed that MAVS and IRF3 were the targets of gE, and the specific mechanism was that gE inhibited IFN-ß production by promoting MAVS ubiquitination and interfering with the interaction between IRF3 and CBP/p300. These results suggest a new way of BoHV-1 inhibition of IFN-ß production to evade the host innate immunity.

Bovine papular stomatitis virus as a vaccine vector for cattle.

Virus vectored vaccines are not available commercially for cattle even though compelling potential applications exist. Bovine papular stomatitis virus (BPSV), a highly prevalent parapoxvirus, causes self-limited oral lesions in cattle. Ability of virus to accommodate large amounts of foreign DNA, induce low level of antiviral immunity, and circulate and likely persist in cattle populations, make BPSV an attractive candidate viral vector. Here, recombinant BPSV were constructed expressing either Bovine herpesvirus 1 (BoHV-1) glycoprotein gD (BPSVgD), or gD and gB (BPSVgD/gB). Immunization of BPSV serologically-positive calves with BPSVgD or BPSVgD/gB induced BoHV-1 neutralization antibodies and provided protection for three of four animals following a high dose BoHV-1 challenge at day 70 pi. Results indicate BPSV suitability as a candidate virus vector for cattle vaccines.

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.

A Rapid Nucleic Acid Visualization Assay for Infectious Bovine Rhinotracheitis Virus That Targets the TK Gene.

Infectious bovine rhinotracheitis virus (IBRV) can cause various degrees of symptoms in the respiratory system, reproductive system, and whole body of cattle. It also can lead to persistent and latent infection in cattle, posing a challenge to timely control of infectious bovine rhinotracheitis (IBR) in farms and causing large financial losses in the global cattle industry. Therefore, the goal of this study was to establish a rapid, simple, and accurate method that can detect IBRV in order to facilitate the control and eradication of IBR in cattle. We combined recombinant polymerase amplification (RPA) with a closed vertical flow visualization strip (VF) and established an RPA-VF assay that targets the thymidine kinase (TK) gene to rapidly detect IBRV. This method (reaction at 42°C for 25 min) was able to detect a minimum of 3.8 × 101 copies/µL of positive plasmid and 1.09 × 101 50% tissue culture infective dose (TCID50) of the IBRV. This assay has high specificity for IBRV and does not cross-react with other respiratory pathogens in cattle. The concordance between the RPA-VF assay and the gold standard was 100%. In addition, this assay was also suitable for the detection of DNA from clinical samples extracted by a simple method (heating at 95°C for 5 min), which can achieve the rapid detection of clinical samples in the field. Overall, the present sensitivity, specificity, and clinical applicability assessments indicated that the RPA-VF assay we developed can be utilized as a quick and accurate on-site test for IBRV detection in farms. IMPORTANCE IBRV causes different degrees of clinical symptoms in cattle and poses a great threat to the cattle industry. The infection is persistent and latent, and the elimination of IBRV in infected herds is difficult. A rapid, simple, and accurate method to detect IBRV is therefore vital to control and eradicate IBR. Combining RPA with an VF, we established an RPA-VF assay for the rapid detection of IBRV, which can complete the test of clinical samples in 35 min. The assay shows good sensitivity, specificity, and clinical applicability and can be used as an on-site test for IBRV in farms.

NFAT5 Restricts Bovine Herpesvirus 1 Productive Infection in MDBK Cell Cultures.

Bovine herpesvirus 1 (BoHV-1), an important bovine viral pathogen, causes severe disease in the upper respiratory tract and reproductive system. Tonicity-responsive enhancer-binding protein (TonEBP), also known as nuclear factor of activated T cells 5 (NFAT5), is a pleiotropic stress protein involved in a range of cellular processes. In this study, we showed that the knockdown of NFAT5 by siRNA increased BoHV-1 productive infection and overexpression of NFAT5 via plasmid transfection decreased virus production in bovine kidney (MDBK) cells. Virus productive infection at later stages significantly increased transcription of NFAT5 but not appreciably alter measurable NFAT5 protein levels. Virus infection relocalized NFAT5 protein and decreased the cytosol accumulation. Importantly, we found a subset of NFAT5 resides in mitochondria, and virus infection led to the depletion of mitochondrial NFAT5. In addition to full-length NFAT5, another two isoforms with distinct molecular weights were exclusively detected in the nucleus, where the accumulation was differentially affected following virus infection. In addition, virus infection differentially altered mRNA levels of PGK1, SMIT, and BGT-1, the canonical downstream targets regulated by NFAT5. Taken together, NFAT5 is a potential host factor that restricts BoHV-1 productive infection, and virus infection hijacks NFAT5 signaling transduction by relocalization of NFAT5 molecules in cytoplasm, nucleus, and mitochondria, as well as altered expression of its downstream targets. IMPORTANCE Accumulating studies have revealed that NFAT5 regulates disease development due to infection of numerous viruses, underlying the importance of the host factor in virus pathogenesis. Here, we report that NFAT5 has capacity to restrict BoHV-1 productive infection in vitro. And virus productive infection at later stages may alter NFAT5 signaling pathway as observed by relocalization of NFAT5 protein, reduced accumulation of NFAT5 in cytosol, and differential expression of NFAT5 downstream targets. Importantly, for the first time, we found that a subset of NFAT5 resides in mitochondria, implying that NFAT5 may regulate mitochondrial functions, which will extend our knowledge on NFAT5 biological activities. Moreover, we found two NFAT5 isoforms with distinct molecular weights were exclusively detected in the nucleus, where the accumulation was differentially affected following virus infection, representing a novel regulation mechanism on NFAT5 function in response to BoHV-1infection.

Recombinant BoHV-5 glycoprotein (rgD5) elicits long-lasting protective immunity in cattle.

BoHV-5 is a worldwide distributed pathogen usually associated with a lethal neurological disease in dairy and beef cattle resulting in important economic losses due to the cattle industry. Using recombinant gD5, we evaluated the long-duration humoral immunity of the recombinant vaccines in a cattle model. Here we report that two doses of intramuscular immunization, particularly with the rgD5ISA vaccine, induce long-lasting antibody responses. Recombinant gD5 antigen elicited tightly mRNA transcription of the Bcl6 and the chemokine receptor CXCR5 which mediate memory B cells and long-lived plasma cells in germinal centers. In addition, using an in-house indirect ELISA we observed higher and earlier responses of rgD5-specific IgG antibody and the upregulation of mRNA transcription of IL2, IL4, IL10, IL15, and IFN-γ in rgD5 vaccinated cattle, indicating a mixed immune response. We further show that rgD5 immunization protects against both BoHV -1 and -5. Our findings indicate that the rgD5-based vaccine represents an effective vaccine strategy to induce an efficient control of herpesviruses.

Characterization and phylogenetic analysis of bovine gammaherpesvirus 4 isolated in China, 2022.

Bovine gammaherpesvirus 4 (BoHV-4) is a common virus detected in bovine with respiratory disease worldwide. In this study, we identified and characterized a novel BoHV-4 strain, referred as HB-ZJK, in vaginal swabs collected from cattle in China, 2022. The long unique region (LUR) of HB-ZJK is 10,9811 bp in length. It shares 99.17% to 99.38% nucleotide identity to five BoHV-4 strains available in GenBank and the highest similarity was seen with BoHV-4V. test (JN133502.1) strain (99.38%). Mutations, insertions or deletions were observed mainly in HB-ZJK gB (ORF8), TK (ORF21), gH (ORF22), MCP (ORF25), PK (ORF36), gM (ORF39), and gL (ORF47) genes compared to its genomic coordinates. Phylogenetic analyses of gB and TK genes showed that HB-ZJK clustered with China 512 (2019), B6010 (2009), and J4034 (2009) strains, demonstrating that the isolated HB-ZJK belongs to genotype 1. This is the first report that has revealed a comprehensive genome profile of BoHV-4 strain in China. This study will provide foundation for epidemiological investigations of BoHV-4 and contribute to the molecular and pathogenic studies of BoHV-4.

Expression of apoptosis-related genes at different stages of BoHV-1 and 5 infection of bovine neural tissue.

Bovine alphaherpesviruses (BoHV) 1 and 5 share many genetic and structural characteristics; however, they differ in their ability to cause encephalitis. Previous research suggests that this difference might be caused by a differential modulation of apoptosis. In this study, we analyzed the mRNA expression of Bax, Bcl-2, Fas and caspases 3 and 8 in neural tissue sections of BoHV-1 and BoHV-5 experimentally-infected cattle. Overall, Fas and caspase 3 mRNA was up-regulated during BoHV-5 acute infection, latency, and reactivation. Conversely, caspase 3 mRNA levels increased only in the olfactory cortex during BoHV-1 acute infection, and it was down-regulated during reactivation, while Fas was only up-regulated during BoHV-1 acute infection and latency. Moreover, Bax/Bcl-2 ratio was lower than 1 during BoHV-1 acute infection except in the trigeminal ganglion, whereas many brain regions exhibit a ratio higher than 1 during BoHV-5 acute infection and reactivation. In summary, our findings suggest that during acute infection and reactivation, BoHV-5 induces a pro-apoptotic condition that could partially justify its increased ability to cause neurological damage.

Assessment of Rapid MinION Nanopore DNA Virus Meta-Genomics Using Calves Experimentally Infected with Bovine Herpes Virus-1.

Bovine respiratory disease (BRD), which is the leading cause of morbidity and mortality in cattle, is caused by numerous known and unknown viruses and is responsible for the widespread use of broad-spectrum antibiotics despite the use of polymicrobial BRD vaccines. Viral metagenomics sequencing on the portable, inexpensive Oxford Nanopore Technologies MinION sequencer and sequence analysis with its associated user-friendly point-and-click Epi2ME cloud-based pathogen identification software has the potential for point-of-care/same-day/sample-to-result metagenomic sequence diagnostics of known and unknown BRD pathogens to inform a rapid response and vaccine design. We assessed this potential using in vitro viral cell cultures and nasal swabs taken from calves that were experimentally challenged with a single known BRD-associated DNA virus, namely, bovine herpes virus 1. Extensive optimisation of the standard Oxford Nanopore library preparation protocols, particularly a reduction in the PCR bias of library amplification, was required before BoHV-1 could be identified as the main virus in the in vitro cell cultures and nasal swab samples within approximately 7 h from sample to result. In addition, we observed incorrect assignment of the bovine sequence to bacterial and viral taxa due to the presence of poor-quality bacterial and viral genome assemblies in the RefSeq database used by the EpiME Fastq WIMP pathogen identification software.

Bovine Herpesvirus-1 Glycoprotein M Mediates the Translocation to the Golgi Apparatus and Packaging of VP8.

VP8, the most abundant tegument protein of bovine herpesvirus-1 (BoHV-1), plays an important role in viral replication. According to our previous studies, VP8 localizes to the Golgi apparatus of BoHV-1-infected cells where it can be packaged into the virus; however, Golgi localization of VP8 does not occur outside of the context of infection. The goal of this study was to identify the viral factor(s) involved in the tropism of VP8 towards the Golgi. VP8 was found to interact with glycoprotein M (gM), and the VP8 and gM domains that are essential for this interaction were identified. VP8 and gM colocalized to the Golgi apparatus in BoHV-1-infected cells. In cells co-transfected with VP8- and gM-encoding plasmids, VP8 was also found to be localized to the Golgi, suggesting gM to be sufficient. The localization of VP8 to the Golgi was lost in cells infected with a gM deletion mutant, and the amount of VP8 incorporated into mature virus was significantly reduced. However, with the restoration of gM in a revertant virus, the localization to the Golgi and the amount of VP8 incorporated in the virions were restored. These results indicate that gM plays a critical role in VP8 subcellular localization to the Golgi and packaging into mature virions.

Subunit vaccine based on glycoprotein B protects pattern animal guinea pigs from tissue damage caused by infectious bovine rhinotracheitis virus.

Infectious bovine rhinotracheitis (IBR) is caused by Bovine herpesvirus type 1 (BoHV-1), which seriously threatens the global cattle industry. Only vaccination to improve immunity is the most direct and effective means to prevent IBR. Attempts are being made to use subunit vaccines, deleted or recombinant viral vaccines to reduce or eradicate IBR. For investigating the immunological characteristics of glycoprotein B subunit vaccine in pattern animal guinea pigs, the partial glycoprotein B (gB) of BoHV-1 with dominant antigenic characteristic was selected. A recombinant prokaryotic expression vector pET-32a-gB with the truncated gB gene was constructed, expressed, identified and the purified proteins were used to immunize guinea pigs. The immune effect of the subunit vaccine was assessed by monitoring clinical symptoms, viral load, antibody secretion, and histopathological changes. The results indicated that guinea pigs immunized with the gB subunit vaccine produced high levels of anti-gB antibodies and virus-neutralizing antibodies. The gB subunit vaccine significantly reduced viral shedding and lung tissue damage after IBRV challenge. The animals inoculated the gB subunit vaccine also had less virus reactivation. Its protective effect on viral shedding and tissue damage was similar to that of inactivated BoHV-1 vaccine. This work is a proof-of-concept study of subunit vaccine-induced protection against BoHV-1. And it is expected to be a candidate vaccine for the prevention of IBR.

Recombinant Bovine Herpesvirus Type I Expressing the Bovine Viral Diarrhea Virus E2 Protein Could Effectively Prevent Infection by Two Viruses.

Bovine respiratory disease complex (BRDC) is a comprehensive disease in cattle caused by various viral and bacterial infections. Among them, bovine herpesvirus type I (BoHV-1) and bovine viral diarrhea virus (BVDV) play important roles and have caused huge financial losses for the cattle industry worldwide. At present, vaccines against BRDC include trivalent attenuated BoHV-1, BVDV-1, and BVDV-2 live vaccines, BoHV-1 live attenuated vaccines, and BoHV-1/BVDV bivalent live attenuated vaccines, which have limitations in terms of their safety and efficacy. To solve these problems, we optimized the codon of the BVDV-1 E2 gene, added the signal peptide sequence of the BoHV-1 gD gene, expressed double BVDV-1 E2 glycoproteins in tandem at the BoHV-1 gE gene site, and constructed a BoHV-1 genetics-engineered vectored vaccine with gE gene deletion, named BoHV-1 gE/E2-Linker-E2+ and BoHV-1 ΔgE. This study compared the protective effects in BoHV-1, BoHV-1 ΔgE, BoHV-1 gE/E2-Linker-E2+, and BVDV-1 inactivated antigen immunized guinea pigs and calves. The results showed that BoHV-1 gE/E2-Linker-E2+ could successfully induce guinea pigs and calves to produce specific neutralizing antibodies against BVDV-1. In addition, after BoHV-1 and BVDV-1 challenges, BoHV-1 gE/E2-Linker-E2+ can produce a specific neutralizing antibody response against BoHV-1 and BVDV-1 infections. Calves immunized with this type of virus can be distinguished as either vaccinated animals (gE-) or naturally infected animals (gE+). In summary, our data suggest that BoHV-1 gE/E2-Linker-E2+ and BoHV-1 ΔgE have great potential to prevent BVDV-1 or BoHV-1 infection.

In-Depth Temporal Transcriptome Profiling of an Alphaherpesvirus Using Nanopore Sequencing.

In this work, a long-read sequencing (LRS) technique based on the Oxford Nanopore Technology MinION platform was used for quantifying and kinetic characterization of the poly(A) fraction of bovine alphaherpesvirus type 1 (BoHV-1) lytic transcriptome across a 12-h infection period. Amplification-based LRS techniques frequently generate artefactual transcription reads and are biased towards the production of shorter amplicons. To avoid these undesired effects, we applied direct cDNA sequencing, an amplification-free technique. Here, we show that a single promoter can produce multiple transcription start sites whose distribution patterns differ among the viral genes but are similar in the same gene at different timepoints. Our investigations revealed that the circ gene is expressed with immediate-early (IE) kinetics by utilizing a special mechanism based on the use of the promoter of another IE gene (bicp4) for the transcriptional control. Furthermore, we detected an overlap between the initiation of DNA replication and the transcription from the bicp22 gene, which suggests an interaction between the two molecular machineries. This study developed a generally applicable LRS-based method for the time-course characterization of transcriptomes of any organism.

Genetic characterization of upper respiratory tract virome from nonvaccinated Egyptian cow-calf operations.

Bovine respiratory disease (BRD) is the costliest complex disease affecting the cattle industry worldwide, with significant economic losses. BRD pathogenesis involves several interactions between microorganisms, such as bacteria and viruses, and management factors. The present study aimed to characterize the nasal virome from 43 pooled nasal swab samples collected from Egyptian nonvaccinated cow-calf operations with acute BRD from January to February 2020 using metagenomic sequencing. Bovine herpesvirus-1 (BHV-1), first detection of bovine herpesvirus-5 (BHV-5), and first detection of bovine parvovirus-3 (BPV-3) were the most commonly identified in Egyptian cattle. Moreover, phylogenetic analysis of glycoprotein B revealed that the BHV-1 isolate is closely related to the Cooper reference strain (genotype 1.1), whereas the BHV-5 isolate is closely related to the reference virus GenBank NP_954920.1. In addition, the whole-genome sequence of BPV-3 showed 93.02% nucleotide identity with the reference virus GenBank AF406967.1. In this study, several DNA viruses, such as BHV-1 and first detection BHV-5, and BPV-3, were detected and may have an association with the BRD in Egyptian cattle. Therefore, further research, including investigating more samples from different locations to determine the prevalence of detected viruses and their contributions to BRD in cattle in Egypt, is needed.

Bovine Herpesvirus 1 Invasion of Sensory Neurons by Retrograde Axonal Transport Is Dependent on the pUL37 Region 2 Effector.

Following exposure and replication at mucosal surfaces, most alphaherpesviruses invade the peripheral nervous system by retrograde axonal transport and establish lifelong latent infections in the peripheral ganglia. Reactivation of ganglionic infections is followed by anterograde axonal transport of virions back to body surfaces where viral replication results in disease that can range from moderate to severe in presentation. In the case of bovine herpesvirus 1 (BoHV-1), replication in the epithelial mucosa presents as infectious bovine rhinotracheitis (IBR), a respiratory disease of significant economic impact. In this study, we provide a live-cell analysis of BoHV-1 retrograde axonal transport relative to the model alphaherpesvirus pathogen pseudorabies virus (PRV) and demonstrate that this critical neuroinvasive step is conserved between the two viruses. In addition, we report that the BoHV-1 pUL37 tegument protein supports processive retrograde motion in infected axons and invasion of the calf peripheral nervous system. IMPORTANCE A molecular and cellular understanding of the retrograde axonal transport process that underlies the neuroinvasive properties of the alphaherpesviruses is established from studies of herpes simplex virus and pseudorabies virus. The degree to which this phenotype is conserved in other related viruses has largely not been examined. We provide a time-lapse analysis of the retrograde axonal transport kinetics of bovine herpesvirus 1 and demonstrate that mutation of the pUL37 region 2 effector affords a strategy to produce live-attenuated vaccines for enhanced protection of cattle.