Studies on experimental enteric salmonellosis in ponies.

This research paper explores the clinical, bacteriological, serological, and haematological effects of Salmonella typhimurium on adult ponies, comparing them with control subjects.

Study Design and Participants

• The study focused on the results of 13 adult ponies that were orally inoculated with Salmonella typhimurium, a bacterial pathogen known for causing foodborne illness.
• These results were compared with two control ponies that were not infected and four others that were infected accidentally.

Observations and Results

• Clinical responses observed in the inoculated ponies included fever (pyrexia) lasting four days and a reduction in white blood cells (neutropenia) during the first five days after inoculation. This was then followed by an increase in white blood cells (neutrophilia).
• The fever and neutropenia appeared to be associated with the highest shedding of salmonella organisms in the rectal feces of the ponies.
• The researchers also noticed changes in the character of the feces 1-2 days after inoculation, which seems correlated with the serological (blood) response to the infection.
• All the infected ponies showed serological responses except one.
• During the postmortem (necropsy) examination, 14 ponies had positive cultures of salmonella in the colon. Interestingly, half of these had negative salmonella cultures in their rectal feces.

Additional Observations

• The researchers also carried out serological studies on 43 healthy horses. This showed a correlation between the horse’s age and its salmonella agglutination (clumping) titre – a measurement of the body’s immune response to the infection. This suggests that older horses may have stronger immune responses to Salmonella typhimurium, though the study does not specify the direction of this correlation.