Contagious equine metritis: effect of vaccination on control of the disease.

The research article presents an investigation into the impact of vaccination methods on controlling Contagious Equine Metritis (CEM) in mares. The study found that vaccination reduced the severity of the disease, despite there being clinical signs of CEM present.

Research methods

• The researchers used pony mares as subjects for this experiment, vaccinating them with killed CEM bacteria. The vaccination was administered via different routes – intravenously, subcutaneously, and intrauterinely, or a combination of these methods.
• After vaccination, the mares’ serum agglutinating antibody titers were observed. The titers fluctuated between 1:64 to 1:1,024, indicating a change in the concentration of antibodies against the bacteria.
• Following this, the mares were exposed to a 96-hour-old culture of CEM bacteria via the intrauterine route as a means to challenge the immune response. Both vaccinated and non vaccinated mares showed clinical signs of CEM.

Research findings

• The vaccinated mares displayed less severe clinical signs of CEM in comparison to non-vaccinated mares, showing that vaccination might reduce the severity of the disease. The bacteria were isolated from the exudate and uterine samples collected from the mares after exposure to the disease, suggesting that the bacteria were actively infecting the mares.
• Low titers of Intrauterine (IU) antibodies to CEM bacteria were observed in infected mares through various agglutination tests, including plate, tube and antiglobulin, and through an enzyme-linked immunosorbent assay.
• However, a high antibody titer was noted when passive hemagglutination test was used, indicating that this method of testing might be more sensitive or able to detect a broader range of antibodies against CEM bacteria.

Conclusion

• This study provides useful insights regarding the role of vaccination in managing CEM in mares and suggests that vaccinations may potentially offer a promising solution to control the disease. However, more research would be beneficial to further understand the varying results of the titer tests and assess the effectiveness of the vaccination in a broader context.