ABSTRACT
Bovine alphaherpesvirus 1 (subtypes 1.1, 1.2a, and 1.2b), type 5 (subtypes 5a, 5b, and 5c), and bubaline herpesvirus 1 (BuHV-1) induce highly, though not fully cross-reactive serological responses. Most types and subtypes of these viruses circulate particularly in countries of the southern hemisphere, notably Brazil and Argentina. Therefore, the detection of infected animals is important in defining prevention and control strategies, particularly when flocks are destined for international trade. Identification of infected herds is most often achieved by assays that detect antibodies, such as enzyme immunoassays (ELISAs). However, to date, no ELISA has been evaluated in its capacity to detect antibodies to these alphaherpesviruses. Here, an ELISA was developed to detect antibodies to all currently recognized BoAHV-1, BoAHV-5, and BuAHV-1 types/subtypes, and its sensitivity and specificity were determined. Six hundred bovine sera were screened in serum neutralization tests (SN) against the seven viruses. ELISAs prepared with each of the viruses were compared to SN. Subsequently, a combined assay with multiple antigens LISA was prepared by mixing five viral antigens, chosen for their highest sensitivity in the preparative assays. In comparison to SN, the mAgELISA sensitivity was 96.5% with 96.1% specificity (κ = 0.93; PPV = 95.0%; NPV = 97.3%). The findings reveal that the mAgELISA developed here is highly suitable for the detection of antibodies, comparable in sensitivity and specificity to that of SN when performed with all known types and subtypes of bovine and bubaline alphaherpesviruses.
ABSTRACT
Bubaline alphaherpesvirus 1 (BuHV1) is a member of the family Herpesviridae, subfamily Alphaherpesvirinae, genus Varicellovirus. To date, no full genome sequence of BuHV has been published. Here, we report the complete genome sequence of bubaline alphaherpesvirus 1 (BuHV1) strain b6 (BuHV1-b6), isolated from a water buffalo (Bubalus bubalis) in 1972 in Australia. The virus was multiplied in MDBK cells, and the DNA was extracted and subjected to high-throughput sequencing. The reads were aligned and combined into a single genome sequence, with bovine alphaherpesvirus 5 (BoHV5) strain SV507/99 (accession number NC005261) as a reference. The BuHV1-b6 genome is a linear double-stranded DNA molecule, 137,452 bp long, with a GC content of 76.8%. The genome consists of two unique sequences: a long, or UL, sequence (103,818 bp) and a short, or US, sequence (9,586 bp), with the latter being flanked by inverted IR and TR elements of 12,024 bp each. The arrangement is typical of herpesvirus genomes of the D-type. The overall sequence has a 92.2% similarity at the nucleotide level to the reference BoHV5 strain. Our report provides a significant landmark in the history of herpesviruses, represented by the genome sequence of this 44-year-old virus isolate.
Subject(s)
Buffaloes/virology , DNA, Viral/genetics , Genome, Viral/genetics , Varicellovirus/genetics , Animals , Australia , Base Sequence , Cattle , Cell Line , Dogs , High-Throughput Nucleotide Sequencing , Madin Darby Canine Kidney Cells , Sequence Analysis, DNA , Varicellovirus/classification , Varicellovirus/isolation & purificationABSTRACT
An experimental oil-adjuvanted, inactivated vaccine against bovine herpesvirus type 1 (BHV-1.1), was produced and evaluated in its capacity to induce neutralizing antibodies against bovine herpesvirus type 1 (BHV-1, subtypes 1.1 and 1.2) and bovine herpesvirus type 5 (BHV-5). Cattle were vaccinated and revaccinated 90 days later. Antibodies were measured at days 0, 30, 90, 120, 180, 270 and 450 days after the first dose of vaccine (DPV). Antibody titres to BHV-1.1 and BHV-1.2 were significantly higher than to BHV-5 throughout the experiment. While all calves seroconverted to BHV-1.1 and BHV-1.2 after the first dose of vaccine, only two out of 23 (8,7 percent) calves seroconverted to BHV-5. However, after the booster injection all animals seroconverted to the three virus types. At 450 DPV, 79 percent (15/19 cattle) and 84 percent (16/19) were still positive for antibodies to BHV 1.1 and BHV 1.2, whereas 50 percent (10/19) of the calves remained seropositive for BHV-5. It was concluded that although a potent BHV-1 vaccine may induce crossreactive neutralizing antibodies to BHV-5, the levels of such antibodies are significantly lower and of shorter duration than antibodies to BHV-1.1 or BHV-1.2
