Equine influenza: patterns of disease and seroprevalence in Thoroughbred studs and implications for vaccination.

This research focuses on evaluating the prevalence and patterns of Equine Influenza (EI) in Thoroughbred studs in Australia, and the impact of vaccination on disease detection and prevention.

Study Description and Aims

• The research was conducted in ten large Thoroughbred horse studs located in the upper Hunter Valley of New South Wales and in southeast Queensland, Australia.
• The study aimed to describe the EI epidemic among studs in the Special Restricted Area, referred to as Purple Zone, of New South Wales.
• Additionally, the intent was to estimate the level of EI presence (seroprevalence) among diverse groups of horses within these studs.
• The study also sought to examine signs of exposure to the EI virus among horses in ‘vaccinated’ studs in southeast Queensland that were assumed to have remained uninfected.

Serology Results and Implications for Vaccination

• Serology is the study of body fluids, like blood, to detect the presence of antibodies against viruses such as EI. The serology results from this study suggested reduced sensitivity of clinical surveillance in detecting infection in ‘vaccinated’ premises.
• This outcome indicates that the vaccination protocol may hamper the accurate detection of the EI virus among vaccinated horse populations. This can lead to a false impression of a disease-free environment while the virus may still be present.
• The researchers concluded that when considering vaccine efficacy, it’s important to not only evaluate the reduction in clinical disease but also take into account the infection and infectiveness rates. This approach would give a more comprehensive understanding of the vaccine’s effectiveness in controlling the disease in horse populations.

Impact on Future Vaccination Strategies

• The findings of this study can significantly influence future strategies for EI vaccination among horse herds. Understanding the limitations of current vaccination measures in accurately detecting disease incidence can help inform more effective management practices.
• Such knowledge can guide the modification of existing vaccination protocols to increase their sensitivity and specificity, thereby improving overall disease management in domestic horse populations.