Characterization of the first bovine gammaherpesvirus 4 strain isolated from an aborted bovine fetus in Argentina

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.

Whole Genome Sequence-Based Analysis of Bovine Gammaherpesvirus 4 Isolated from Bovine Abortions

Bovine gammaherpesvirus 4 (BoGHV4) is a member of the Gammaherspivirinae subfamily, Rhadinovirus genus. Its natural host is the bovine, and it is prevalent among the global cattle population. Although the complete genome of BoGHV4 has been successfully sequenced, the functions of most of its genes remain unknown. Currently, only six strains of BoGHV4, all belonging to Genotype 1, have been sequenced. This is the first report of the nearly complete genome of Argentinean BoGHV4 strains isolated from clinical cases of abortion, representing the first BoGHV4 Genotype 2 and 3 genomes described in the literature. Both Argentinean isolates presented the highest nt p-distance values, indicating a greater level of divergence. Overall, the considerable diversity observed in the complete genomes and open reading frames underscores the distinctiveness of both Argentinean isolates compared to the existing BoGHV4 genomes. These findings support previous studies that categorized the Argentinean BoGHV4 strains 07-435 and 10-154 as Genotypes 3 and 2, respectively. The inclusion of these sequences represents a significant expansion to the currently limited pool of BoGHV4 genomes while providing an important basis to increase the knowledge of local isolates.

Molecular survey of selected viruses in Pudus (Pudu puda) in Chile revealing first identification of caprine herpesvirus-2 (CpHV-2) in South American ungulates

Viral diseases jeopardize the health of wildlife in Chile. However, this country lacks health surveillance programs that allow for defining preventive measures to tackle such diseases. The objective of this study was to determine the occurrence and the genetic diversity of pestivirus, herpesvirus and adenovirus in pudus from Chile. Blood samples from wild (n=34) and captive (n=32) pudus were collected between 2011 and 2019 and analyzed through consensus PCR. All the samples were negative to pestivirus and adenovirus. Herpesvirus was confirmed in four captive, and one wild pudu. All four zoo animals share the same sequence for both polymerase and glycoprotein genes. Both sequences share a 100% identity with caprine herpesvirus-2, classifying them in the same cluster as the Macavirus group. In turn, novel sequences of the polymerase and glycoprotein B genes were obtained from the wild pudu. Our study reports the first evidence of CpHV-2 infection in Chile and South American ungulate populations. Further research will be necessary to assess the pathogenicity of CpHV-2 in this species. It is also urgently recommended that molecular, serological and pathological screening should be conducted in Chilean wild and captive pudus to understand the impact of the herpesvirus on their populations.

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.

Mesenchymal Stem Cells in Embryo-Maternal Communication under Healthy Conditions or Viral Infections: Lessons from a Bovine Model

Bovine mesenchymal stem cells are a relevant cell population found in the maternal reproductive tract that exhibits the immunomodulation capacity required to prevent embryo rejection. The phenotypic plasticity showed by both endometrial mesenchymal stem cells (eMSC) and embryonic trophoblast through mesenchymal to epithelial transition and epithelial to mesenchymal transition, respectively, is essential for embryo implantation. Embryonic trophoblast maintains active crosstalk via EVs and soluble proteins with eMSC and peripheral blood MSC (pbMSC) to ensure the retention of eMSC in case of pregnancy and induce the chemotaxis of pbMSC, critical for successful implantation. Early pregnancy-related proteins and angiogenic markers are detected as cargo in EVs and the soluble fraction of the embryonic trophectoderm secretome. The pattern of protein secretion in trophectoderm-EVs changes depending on their epithelial or mesenchymal phenotype and due to the uptake of MSC EVs. However, the changes in this EV-mediated communication between maternal and embryonic MSC populations infected by viruses that cause abortions in cattle are poorly understood. They are critical in the investigation of reproductive viral pathologies.

Isolation and molecular characterization of bovine herpesvirus 4 from cattle in mainland China

Bovine herpesvirus 4 (BoHV-4) is one of the most important of the known viral respiratory and reproductive pathogens of both young and adult cattle. However, BoHV-4 has not been isolated or detected in mainland China prior to this study. In 2019, BoHV-4 strain 512 was isolated from cattle in Heilongjiang Province, China, using MDBK cells, and characterized by PCR, nucleotide sequence analysis, and transmission electron microscopy. Two other unknown herpesvirus strains, BL6010 and J4034, which were isolated from cattle in 2009 in China and stored at -70℃, were also propagated in MDBK cells and identified as BoHV-4 by PCR. Phylogenetic analysis based on partial nucleotide sequences of the thymidine kinase (TK) gene and glycoprotein B (gB) gene for the three isolates indicated that these three Chinese strains belong to BoHV-4 genotype 1. A preliminary virus neutralization test revealed that 64% of the 70 bovine sera (45/70) collected from Inner Mongolia Autonomous Region, China, had anti-BoHV-4 antibodies and that natural BoHV-4 infection occurred in cattle in China. Here, we report for the first time the isolation and molecular characterization of BoHV-4 from cattle in mainland China.

Genetic characterization of bovine herpesvirus 4 (BoHV-4) isolates from Argentine cattle suggests a complex evolutionary scenario

Bovine herpevsirus 4 (BoHV-4) is a gammaherpesvirus that has been associated with different clinical conditions in cattle. In Argentina, BoHV-4 was detected in diverse bovine samples. The aim of this study was to analyze the genetic relationship of 48 field BoHV-4 strains isolated from cattle in Argentina. According to thymidine kinase (tk) gene sequences, BoHV-4 isolates belong to genotypes 1, 2 and 3. Phylogenetic analyses confirmed the presence of the three previously described viral genotypes. However, some of the studied isolates presented conflicting phylogenetic signals between the studied markers. This suggests a complex evolutionary background, that is a history of recombination, incomplete lineage sorting (deep coalescence) or a combination of these, which requires further study. These potential events make difficult the diagnosis of BoHV-4 from clinical samples of cattle and may pose a significant problem for the control of the virus in the herds.