Standardization of an experimental disease model of Streptococcus zooepidemicus in the equine.

The research article focuses on creating a reliable experimental model of a disease in horses caused by the bacterium Streptococcus zooepidemicus. The researchers were successful in creating a consistent disease model and also studied how the disease impacts specific elements in hematology, serum chemical profiles, and different protein fractions.

Development of the Disease Model

• The researchers were aiming to create a reproducible experimental model of a horse disease caused by Streptococcus zooepidemicus. This bacterium can cause a variety of diseases in horses, including respiratory and joint infections.
• To create the model, they administered a challenge dose of the bacteria directly into the bloodstream of the horses.
• Specifically, they first introduced a dose of 1 X 10(10) colony-forming units (CFU) of the bacterium, followed 24 hours later with another dose of 1 X 10(8) CFU.
• This resulted in the horses developing a disease characterized by depression, fever, lack of appetite, abnormal lung sounds, inflammation of joints, significant lameness, and a slow deterioration of physical condition and thinness.

Study of Disease Impact

• Following the development of the disease model, the researchers then studied the effects of the disease on various hematological and serum chemical parameters.
• The disease did not appear to affect serum glucose, sodium, potassium, chloride, urea nitrogen, creatinine, uric acid, calcium, phosphorus, and the enzymes SGOT or SGPT.
• However, the disease resulted in a gradual drop in the level of alkaline phosphatase, an enzyme often associated with the liver and bones.
• The levels of serum iron also significantly decreased during the disease and remained low until the last day of the observation period (post-infection day, PID 13).

Changes in Protein Fractions and Predictive Factors

• On studying the protein fractions, the researchers observed a gradual decrease in the level of albumin, a type of protein that helps keep fluid from leaking out of blood vessels, amongst other functions.
• There were increases in the levels of alpha II, beta and gamma globulin, suggesting an immune response to the bacterial infection.
• The elevation of rectal temperatures and white blood cell counts corresponded well with clinical observations of the disease.
• The researchers concluded that serum iron levels could be a valuable predictor of the severity of clinical signs and often dropped before the onset of observable clinical signs and fever.