Recovery of contagious equine metritis organisms and development of lesions in experimental infection of mares.

This study reveals that out of 24 mares experimentally infected with contagious equine metritis, 23 caught the disease. The study tracked the progression of the disease and its ability to remain in different reproductive system locations over time, with a focus on the varying severity and type of inflammation.

Experimental Infection and Recovery of Organisms

• This research was primarily conducted through experimental infection of 24 mares with contagious equine metritis (CEM), a highly infectious disease in horses that affects the reproductive system.
• Among these, 23 were successfully infected with the disease using intrauterine inoculation, a method where the organisms causing CEM were directly introduced into the uterus of the mares.
• The study spanned a period of 2 to 116 days, during which the condition of the mares was intermittently assessed, with the mares being euthanized for precise examination.
• In the mares that were euthanized within 14 days after infection, the CEM organisms were found in the uterus, cervix, vagina, oviduct, and one clitoral sinus. Additionally, it was noticed that their endometrial folds were swollen, and there was a presence of 10-20 ml fluid in the uterus, indicating a significant infection.

Progression of the Disease

• As the experiment progressed, mares that were euthanized after 14 days showed a different pattern. The CEM organisms could be recovered from fewer locations – the ovarian surface (1 mare), oviduct (4 mares), uterus (2 mares), and the clitoral sinus (3 mares).
• This change in the recovery of organisms suggests a time-dependent variation in the disease’s ability to persist in different parts of the mares’ reproductive system.

Lesion Development and Inflammation

• The presence of CEM led to the development of severe endometritis and cervicitis initially which was determined to be acute. Endometritis is the inflammation of the uterus’s inner lining, while cervicitis is the inflammation of the cervix.
• Approximately 14 days into the infection, these conditions became more severe and were predominantly plasmacytic. This term implies that the inflammation was primarily caused by a type of white blood cell called plasma cells, indicating an immune response against the infection.
• The severity of the inflammation eventually declined but was persistent throughout the study