Comparison of antibody and antigen response to intranasal and intramuscular EHV-1 modified-live vaccination in healthy adult horses.

The research article is about a study that compares the antibody and antigen responses in horses after receiving intranasal and intramuscular vaccinations for EHV-1 with a standard EHV-1 modified-live vaccine. The study found that intramuscular vaccination was more effective in triggering immunity.

Introduction and Purpose of the Study

• The researchers wanted to investigate the efficiency of intranasal and intramuscular vaccinations for Equine herpesvirus-1 (EHV-1), a common and often fatal infectious disease in horses.
• The primary objective was to evaluate whether an intranasal EHV-1 modified-live vaccine (MLV) could induce a measurable systemic and/or mucosal immune response.

Methodology

• The study was conducted with 24 healthy adult horses, divided into three groups. Eight horses received the EHV-1 MLV intranasally, another eight received the vaccine intramuscularly, and the remaining group of eight acted as unvaccinated controls for comparison.
• The presence of EHV-1-specific antibodies (total IgG, IgG4/7, IgG1, and IgA) in blood and nasal secretions were measured at three time points: before vaccination, and 14 and 30 days after vaccination. This assessment was intended to measure the immune response triggered by the vaccination.
• In addition, nasal secretions and whole blood samples were tested for the presence of EHV-1 DNA before and 5 days after vaccination to determine any viral infections rising from the vaccination.

Findings and Conclusion

• EHV-1 was detected in nasal secretions of only three horses in the first 48 hours after intranasal administration of the vaccine.
• An increase in the total EHV-1 IgG and IgG4/7 antibodies in blood serum was noted only in those horses that received the intramuscular vaccination.
• There were no significant differences in the antibody values at 14- and 30-days post-vaccination compared to the initial values in horses administered the vaccine intranasally.
• The findings suggest that the intramuscular usage of EHV-1 MLV, as recommended by the manufacturer, is more effective for inciting an immune response.
• The results indicate that the intranasal route of vaccination doesn’t seem to encourage an increase in systemic or nasal antibodies, thereby rendering it suboptimal for vaccinating adult horses with pre-existing antibodies against EHV-1.