Three strains of the FMD virus (A, O, and SAT 2) were recognised as causes of the FMD circulating in Egypt. The aims of this study were to trace the FMDV isolates from outbreaks in Egypt to understand their epidemiology and evolution and to understand the situation of the vaccine strains compared with the circulating serotypes. A meta-analysis was carried out by using the data available for FMD outbreaks in Egypt from GenBank and the World Reference Laboratory for Foot-and-Mouth Disease (WRLFMD); a comparison was done with both data sets for the three serotypes. MEGA-X was used for the evolution analysis, through constructions of phylogenetic trees for all sequences recorded in GenBank for each serotype in different Egyptian outbreaks in different years and also within the same year. Additionally, nucleotide substitution rate, molecular clock, and mean evolutionary rates were estimated for the three serotypes to understand and compare their evolution. Absence of some records of certain serotype outbreaks from the WRLFMD database was noted as were subsequent missing appropriate vaccine programmes. Genetic variation was recorded among the virus isolates within the same years and also the vaccine strain was associated with up to 26 amino acid substitutions. The evolution rate of the SAT2 strain was the highest of the circulating strains. SAT2 had high amino acid substitution per year at an important immunogenic site (130–170), serotype A had less, and serotype O the least. The need for different strategies for vaccine serotype selection is indicated.

The purpose of this study was to determine the effects of vitamin C supplementation on blood oxidative stress biomarkers and antibody response to vaccination in calves. Thirty-four clinically healthy 2 week old Japanese Black calves were randomly assigned to two groups. Seventeen calves formed the VC group which received 1,000 mg of vitamin C daily from 2 to 8 weeks of age, and the other 17 calves of the control group did not receive supplementation. All calves received an inactivated Histophilus somni vaccine at 4 and 8 weeks of age. Blood samples were taken at 2, 4, 8 and 12 weeks of age. The concentration of the serum reactive oxygen metabolites (d-ROMs), and the oxidative stress index (OSI), which is calculated from the d-ROMs and biological antioxidant potential, were significantly lower at 8 weeks of age in the VC group than in the control group (P < 0.05). The antibody titres to H. somni in the VC group were significantly higher than those in the control group at 12 weeks of age after the second vaccination (P < 0.05). Vitamin C supplementation to calves may reduce oxidative stress and enhance the antibody production after vaccination with H. somni.

Swine DNA viruses have developed unique mechanisms for evasion of the host immune system, infection and DNA replication, and finally, construction and release of new viral particles. This article reviews four classes of DNA viruses affecting swine: porcine circoviruses, African swine fever virus, porcine parvoviruses, and pseudorabies virus. Porcine circoviruses belonging to the Circoviridae family are small single-stranded DNA viruses causing different diseases in swine including poly-weaning multisystemic wasting syndrome, porcine dermatitis and nephropathy syndrome, and porcine respiratory disease complex. African swine fever virus, the only member of the Asfivirus genus in the Asfarviridae family, is a large double-stranded DNA virus and for its propensity to cause high mortality, it is currently considered the most dangerous virus in the pig industry. Porcine parvoviruses are small single-stranded DNA viruses belonging to the Parvoviridae family that cause reproductive failure in pregnant gilts. Pseudorabies virus, or suid herpesvirus 1, is a large double-stranded DNA virus belonging to the Herpesviridae family and Alphaherpesvirinae subfamily. Recent findings including general as well as genetic classification, virus structure, clinical syndromes and the host immune system responses and vaccine protection are described for all four swine DNA virus classes.

Canine parvovirus (CPV) disease is one of the most threatening to domestic and wild dogs. A total of 132 clinical samples were isolated from domestic dogs with diarrhoea from Henan, Hubei, Jiangsu, and Anhui provinces from 2016 to 2017, and 56 were positive for CPV-2 by PCR. A phylogenetic tree was constructed for the isolate sequences incorporating 53 non-Chinese reference strains. VP2 sequences showed the strains mainly to be new CPV-2a/2b and CPV-2c genotypes. The Ala5Gly, Phe267Tyr, Ser297Ala, Tyr324Ile, Gln370Arg, Asn426Asp or Asn426Glu, and Thr440Ala sites in the VP2 protein antigenic region were found to have high mutation rates. The VP2 tertiary structural model shows that the change at these mutation points is a factor for the changes in the protein structure. Significant differences between the Central Chinese strains and others were found, indicating that evolution is geographically related and extended in major regions. The homology between the identified strains confirmed their relationship. Phylogenetic analysis indicated that the common genotypes in the same clusters differ slightly in homology and evolutionary history. This epidemiological study enriches the available data and serves as an important reference for studies on the evolution of CPV and selection of vaccines in China.

The objective of this study was to evaluate the efficacy of a modified-live virus (MLV) porcine reproductive and respiratory syndrome virus (PRRSV) vaccine against a heterologous PRRSV-2 challenge in late-term pregnancy gilts under experimental conditions. Eighteen gilts were randomly assigned to vaccinated-challenged, unvaccinated-challenged, and unvaccinated-unchallenged groups (n = 6 gilts per group). Pregnant gilts in the vaccinated-challenged and unvaccinated-unchallenged groups were able to carry their pregnancies to full term and farrowed after 114 to 115 days of gestation. In contrast, pregnant gilts in the unvaccinated-challenged group did not reach full term and farrowed early, after 104 to 108 days of gestation. Pregnant gilts vaccinated with the PRRSV-2 MLV vaccine exhibited a reduction in PRRSV-2 viremia. At the time of challenge with PRRSV-2, vaccinated gilts had relatively low levels of neutralizing antibody titers (≤ 1:16 titer), whereas the number of interferon-γ-secreting cells (IFN-γ-SC) was consistently at protective levels (IFN-γ-SC, ≥ 150 per million). Induction of cell-mediated immunity, as measured by PRRSV-2-specific IFN-γ-SC, correlated with a reduction in PRRSV-2 viremia. Duration of immunity was a minimum of 19 wk. Taken together, the results presented here suggest that vaccination of gilts with a PRRSV-2 MLV vaccine can protect against a heterologous PRRSV-2 challenge and improve the reproductive performance of late-term pregnancy gilts.

Bovine respiratory disease complex is etiologically complex and usually involves co-infection by several agents, including bovine parainfluenza virus-3 (BPIV-3), bovine respiratory syncytial virus (BRSV), and bovine coronavirus (BCoV). Traditionally, vaccines have been tested in seronegative calves infected with a single in vitro-passaged agent, often with little disease, resulting in unvaccinated subjects. To overcome the potential problem of attenuation coincident with in vitro culture of the viruses, cocktails of field isolates of BPIV-3s and BCoVs were passaged in the lungs of neonatal colostrum-deprived calves. Lung lavage fluids were used as inocula, alone and in combination with in-vivo passaged BRSV, and aerosolized into a trailer containing conventionally reared 9-week-old weaned Holstein calves with decayed, but still measurable, maternal antibodies. Calves developed acute respiratory disease of variable severity. Upon necropsy, there were characteristic gross and histologic lesions in the respiratory tract, associated immunohistochemically with BPIV-3, BRSV, and BCoV. In-vivo passage of viruses is an alternative to in vitro culture to produce inocula to better study the pathogenesis of infection and more rigorously and relevantly assess vaccine efficacy.

A prospective study of 65 research beagles kept in a rabies-free environment was undertaken to determine the duration of immunity after they received licensed rabies vaccines. The eventual goal was to extend mandated rabies booster intervals to 5 or 7 years and help reduce the risk of vaccine-associated adverse events. Three groups of dogs were vaccinated with 1 of 2 commercial rabies vaccines or saline at 12 and 15 weeks of age. Beginning 5 years 5 months later, vaccinated and unvaccinated dogs were challenged with virulent rabies virus and observed for 90 days over a series of 3 trials. Humoral and cellular immune responses were examined by serology and flow cytometry. Brain tissue from all challenged dogs was tested for rabies virus. Challenge trial 1 was confounded due to insufficiently virulent virus. In trials 2 and 3 virulent challenge provided 100% mortality in controls. Vaccinate survival was 80% (4/5) after 6 years 7 months, 50% (6/12) after 7 years 1 month, and 20% (1/5) after 8years 0 months. Antibody responses 12 days post-challenge correlated strongly with survival. In a separate non-challenge trial, administration of either a recombinant or a killed rabies vaccine demonstrated memory antibody responses 6 years 1 month after initial vaccination compared with unvaccinated controls. Our data demonstrated that i) duration of immunity to rabies in vaccinated dogs extends beyond 3 years; ii) immunologic memory exists even in vaccinated dogs with serum antibody titer < 0.1 IU/mL; and iii) non-adjuvanted recombinant rabies vaccine induces excellent antibody responses in previously vaccinated dogs 14 days after administration.