Onset of diarrhea and pyrexia and time to detection of Salmonella enterica subsp enterica in feces in experimental studies of cattle, horses, goats, and sheep after infection per os.

This research paper focuses on the timing of detection and onset of symptoms such as diarrhea and pyrexia in animals including cattle, horses, goats, and sheep after they consume food contaminated with Salmonella enterica. It reveals that current methods to identify such infections, based on their appearance within three days of hospital admission, are unreliable due to the varied timeframes in which these symptoms may appear.

Research Method

• A meta-analysis was conducted using 43 studies found in online databases. These studies provided data on cattle, horses, goats, and sheep that had been experimentally infected with Salmonella enterica through oral intake.
• From these studies, the researchers noted the time taken for the presence of Salmonella to be detected in the animals’ feces, and the onset of symptomatic manifestations such as diarrhea and pyrexia (fever).
• The researchers used an Analysis of Covariance to examine the relationships among these variables, looking at selectively distinctive elements such as the host species, age, Salmonella serovar (a subclass/variation of the species), and magnitude of the infecting dose.

Results

• The time to detect Salmonella in feces extended from a half-day to four days since infection.
• The onset of diarrhea and pyrexia varied significantly. Diarrhea was observed between 0.33 to 11 days post-infection, and fever from 0.27 to 5 days.
• A correlation was found between the onset of diarrhea and the host age and Salmonella serovar.
• There were no other significant relationships identified.

Conclusions

• The study concluded that using the time to detect Salmonella in feces as a marker for hospital-acquired infections is not reliable. This is because a standard 3-day criterion can erroneously classify the source of infection (hospital versus community).
• Relying on clinical signs such as the onset of diarrhea and fever to initiate fecal sampling, can increase the risk of environmental contamination and spread within the hospital (nosocomial spread) as these symptoms may only manifest several days after the organism has already been excreted in the feces.