This common bacterial infection is spread through contaminated food or water and affects the intestinal tract. Learn more about prevention and treatment.
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.
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:
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.
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:
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.
Commonly infected foods include:
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.
Infection can also occur if people touch something that is contaminated and then put their fingers in their mouths.
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.
Factors that may increase your risk of salmonella infection include:
The body has many natural defenses against salmonella infection. For example, strong stomach acid can kill many types of salmonella bacteria. But some medical problems or medications can short-circuit these natural defenses.
Some medical problems or medications appear to increase your risk of catching salmonella by weakening your immune system. This interferes with your body's ability to fight infection and disease. Examples include:
Salmonella infection usually isn't life-threatening. However, in certain people — especially infants and young children, older adults, transplant recipients, pregnant women, and people with weakened immune systems — the development of complications can be dangerous.
If you can't drink enough to replace the fluid you're losing from diarrhea, you may become dehydrated. Warning signs include:
If salmonella infection enters your bloodstream (bacteremia), it can infect tissues throughout your body, including:
People who have had salmonella are at higher risk of developing reactive arthritis from salmonella infection. Also known as Reiter's syndrome, reactive arthritis typically causes:
The U.S. Department of Agriculture (USDA) oversees and updates inspection, sampling and testing programs for poultry and meat. The purpose is to cut the number of salmonella infections in the United States.
You can avoid getting salmonella and spreading bacteria to others in several ways, including safely preparing food, hand-washing, avoiding contamination, and not eating raw meat, dairy or egg products.
Preventive methods are especially important when preparing food or providing care for infants, older adults and people with weakened immune systems.
Washing your hands thoroughly can help prevent the transfer of salmonella bacteria to your mouth or to any food you're preparing. Wash your hands with soap and water for 20 seconds after you:
To prevent cross-contamination:
Homemade cookie dough, ice cream, mayonnaise, hollandaise sauce and eggnog all contain raw eggs. If you must consume raw eggs, make sure they've been pasteurized.
Be sure to cook food thoroughly and refrigerate or freeze food promptly.
Salmonella infection is usually diagnosed based on signs and symptoms.
Salmonella infection can be detected by testing a stool sample. However, most people have recovered from their symptoms by the time the test results return.
If your health care provider suspects that you have a salmonella infection in your bloodstream, testing a sample of your blood for the bacteria may be needed.
Most healthy people recover within a few days to a week without specific treatment. Preventing dehydration with adequate fluid intake can help you recover.
Because salmonella infection can cause dehydration, treatment focuses on replacing lost fluids and electrolytes — minerals that balance the amount of water in the body.
If dehydration is severe, emergency room care or hospitalization may be needed so that fluids can be delivered directly into a vein (intravenous).
In addition to advising you to drink plenty of fluids, your health care provider may recommend:
Antibiotics. Your health care provider may prescribe antibiotics to kill the bacteria. These are usually given if your provider suspects that salmonella bacteria have entered your bloodstream, your infection is severe or you have a weakened immune system.
Antibiotics are not helpful in most cases of salmonella infection. In fact, antibiotics may extend the period in which you carry the bacteria and can infect others. They can also increase your risk of getting infected again (relapse).
Even if you don't need medical attention for your salmonella infection, you need to take care not to become dehydrated, a common concern with diarrhea and vomiting.
If you make an appointment with your health care provider, here's some information to help you get ready.
You may want to bring a family member or friend along, if possible. Someone who goes with you may remember information you missed or forgot.
Before your appointment:
Some basic questions to ask include:
Don't hesitate to ask any other questions.
Your health care provider will need to know:
Being prepared to answer questions will help you make the most of your appointment time.