Overview
Salmonella infection (salmonellosis) is a common bacterial disease that affects the intestinal tract. Salmonella bacteria typically live in animal and human intestines and are shed through stool (feces). Humans become infected most frequently through contaminated water or food.
Some people with salmonella infection have no symptoms. Most people develop diarrhea, fever and stomach (abdominal) cramps within 8 to 72 hours after exposure. Most healthy people recover within a few days to a week without specific treatment.
In some cases, diarrhea can cause severe dehydration and requires prompt medical attention. Life-threatening complications also may develop if the infection spreads beyond the intestines. The risk of getting salmonella infection is higher with travel to countries without clean drinking water and proper sewage disposal.
Symptoms
Salmonella infection is usually caused by eating raw or undercooked meat, poultry, and eggs or egg products or by drinking unpasteurized milk. The incubation period — the time between exposure and illness — can be 6 hours to 6 days. Often, people who have salmonella infection think they have the stomach flu.
Possible signs and symptoms of salmonella infection include:
Diarrhea
Stomach (abdominal) cramps
Fever
Nausea
Vomiting
Chills
Headache
Blood in the stool
Signs and symptoms of salmonella infection generally last a few days to a week. Diarrhea may last up to 10 days, but it may take several months before bowels return to usual stool habits.
A few varieties of salmonella bacteria result in typhoid fever, a sometimes deadly disease that is more common in developing countries.
When to see a doctor
Most people don’t need to seek medical attention for salmonella infection because it clears up on its own within a few days.
However, if the affected person is an infant, young child, older adult or someone with a weakened immune system, call a health care provider if illness:
Lasts more than a few days
Is associated with high fever or bloody stools
Appears to be causing dehydration, with signs such as such as urinating less than usual, dark-colored urine and having a dry mouth and tongue
Causes
Salmonella bacteria live in the intestines of people, animals and birds. Most people are infected with salmonella by consuming food or water that has been contaminated by feces.
Infected food and water
Commonly infected foods include:
Raw meat, poultry and seafood. Feces may get onto raw meat and poultry during the butchering process. Seafood may be contaminated if harvested from contaminated water.
Raw or undercooked eggs. While an egg’s shell may seem to be a perfect barrier to contamination, some infected chickens produce eggs that contain salmonella before the shell is even formed. Raw eggs are used in homemade versions of foods such as mayonnaise and hollandaise sauce.
Unpasteurized dairy products. Unpasteurized milk and milk products — sometimes called raw milk — may be contaminated with salmonella. The pasteurization process kills harmful bacteria, including salmonella.
Fruits and vegetables. Some fresh produce, particularly imported varieties, may be irrigated in the field or washed during processing with water contaminated with salmonella. Contamination can also occur in the kitchen, when juices from raw meat and poultry come into contact with uncooked foods, such as salads.
Improperly handled food
Many foods become contaminated when prepared by people who don’t wash their hands thoroughly after using the toilet or changing a diaper or after handling contaminated food.
Infected surfaces
Infection can also occur if people touch something that is contaminated and then put their fingers in their mouths.
Infected pets and other animals
Animals and pets, especially birds and reptiles, may carry salmonella bacteria on their feathers, fur or skin or in their feces. Some pet foods may be contaminated with salmonella and can infect animals.
Source: www.mayoclinic.org
