Occurrence of infectious upper respiratory tract disease and response to vaccination in horses on six sentinel premises in northern Colorado.

The research paper examines how effectively horses in northern Colorado respond to vaccinations against infectious upper respiratory disease (IURD). The study reveals that horses may not produce detectable antibodies after vaccination, which means they might not be protected against diseases like influenza virus and equine herpesviruses (EHVs). Additionally, the study found poor serological response and suggested the need for alternative methods of protecting horses against common respiratory viruses.

Objective of the Research

• The research aimed to investigate the serological response (the level of antibodies present in the blood) of horses to vaccination against influenza virus (H3N8 and H7N7) and EHV in a realistic field setting.
• It also sought to evaluate the association among the vaccination status, serum antibody concentrations, and occurrences of IURD in the monitored horses. In essence, it aimed to understand whether vaccinations were effective in preventing IURD in horses.

Methodology

• The research team conducted the study on six locations in Colorado, where horses were vaccinated parenterally (administered somewhere other than the mouth and alimentary canal, such as intramuscular or subcutaneous administration) against influenza virus and EHV.
• The team then evaluated the serological response in these horses.
• Horses were closely monitored, and biological samples were collected from horses exhibiting clinical signs of IURD, as well as from control horses (those not displaying symptoms).

Findings

• Out of 173 horses, only 61 (35.3%) horses seroconverted (developed detectable antibodies in the blood as a response to vaccination) against EHV, 21 (12.1%) against influenza virus H7N7, and just 4 (2.3%) against influenza virus H3N8.
• The study identified outbreaks of IURD in the sampled horses, which were associated with the influenza virus H3N8 and Streptococcus equi infection.

Conclusion

• The research concluded a poor serological response to vaccination with conventional products, confirming that horses might not show detectable serological responses to conventional vaccination against common respiratory viruses.
• Because of this inadequate response, the conclusion suggests that alternate methods of protecting horses against common respiratory diseases should be sought, as the current conventional vaccinations may not be sufficient or effective.