Salmonellosis is a bacterial infection caused by Salmonella bacteria, which have 2 species, S. enterica and S. bongori and over 2400 serotypes.
Some of these serotypes are named.
In such cases, people often shorten the scientific name to include only the genus and serotype; for example, S. enterica, subspecies enterica, serotype Typhi is shortened to Salmonella Typhi.
Salmonellosis is usually transmitted through contaminated food or water and is typically caused by serotypes of the Salmonella enterica species.
All Salmonella bacteria are bacilli, which means rod-shaped bacteria.
Salmonella has flagella all over its surface, allowing it to move.
In humans, most cases are caused by the S. Enteritidis and S. Typhimurium serotypes.
Other serotypes of Salmonella enterica cause similar infections in other warm-blooded animals.
These include S. Gallinarum in poultry, S. Abortusovis in sheep, S. Choleraesuis in pigs, S. Dublin in cattle, and S. Arizonae in reptiles, among others.
All of these strains can also infect humans.
In humans, Salmonella is typically transmitted through the fecal-oral route, after infected feces come into contact with various foods including raw meat, poultry, eggs, unpasteurized milk, and crops.
Salmonella can also be present on the skin of reptiles and birds and be transmitted through contact with these animals.
When the bacteria are ingested, they travel through the digestive tract, invading and multiplying in intestinal cells.
Infected cells then release proinflammatory cytokines, causing an inflammatory response.
This results in gastroenteritis, or inflammation of the intestinal tract, causing abdominal pain and severe diarrhea.
The bacteria can also enter the blood, termed bacteremia, and cause enteric fever.
From there, they can make their way to other organs like the liver, lungs, heart, and bone to cause focal Salmonella infection.
These symptoms and signs usually arise in humans between 12 and 48 hours after ingestion of the bacteria and typically last for 4 to 7 days.
The Salmonella Typhimurium serotype can cause typhoid fever, which is characterized by similar symptoms including high fever, headache, abdominal pain, and either constipation or diarrhea.
Unlike most other Salmonella infections, typhoid fever can be life threatening and often requires antibiotic treatment.
In infected livestock, most adults have acute enteritis, with fever and severe diarrhea.
In horses, abdominal pain may lead to colic.
