What Is Salmonellosis?

Salmonella is a group of bacteria that can cause diarrheal illness in humans. Because many milder cases are not diagnosed or reported, the actual number of infections may be as many as a million cases a year in the United States. The infection is more common in the summer than winter. It is estimated that hundreds of persons die each year from salmonellosis.

Egg-associated salmonellosis is an important public health problem in the United States. The bacteria Salmonella enteritidis can be inside perfectly normal-appearing eggs, and if the eggs are eaten raw or undercooked, a person may become ill.

What are the symptoms?

People with Salmonella usually develop loose stools, fever, and abdominal cramps 12 to 72 hours after infection. The illness usually lasts 4 to 7 days, and most persons recover without treatment. However, in some persons the diarrhea may be so severe that the patient needs to be hospitalized. In these patients, the Salmonella infection may spread from the intestines to the blood stream, and then to other body sites and can cause death unless the person is treated promptly with antibiotics. The elderly, infants, and those with impaired immune systems are more likely to have a severe illness.

How is Salmonella treated?

Salmonella infections usually do not need treatment and resolve themselves in 5-7 days. Antibiotics are not usually necessary, unless the infection spreads from the intestines. Unfortunately, some Salmonella bacteria have become resistant to antibiotics.

How do people catch this disease?

Salmonella live in the intestinal tracts of humans and other animals, including birds. Salmonella can be transmitted to humans by eating foods contaminated with animal feces. Contaminated foods usually look and smell normal. Contaminated foods are often of animal origin, such as beef, poultry, milk, or eggs, but all foods, including vegetables may become contaminated. Food may also become contaminated by an infected food handler who forgot to wash his or her hands with soap after using the bathroom.

Salmonella may also be found in the feces of some pets, especially those with diarrhea, and people can become infected if they do not wash their hands after contact with these feces. Reptiles are particularly likely to harbor Salmonella and people should always wash their hands immediately after handling a reptile, even if the reptile is healthy.

What can be done to stop the spread of this disease?

Since foods of animal origin may be contaminated with Salmonella, people should not eat raw or undercooked eggs, poultry, or meat. Raw eggs may be unrecognized in some foods such as homemade hollandaise sauce, caesar and other salad dressings, tiramisu, homemade ice cream, homemade mayonnaise, cookie dough, and frostings. Poultry and meat, including hamburgers, should be well-cooked, not pink in the middle. Persons also should not consume raw or unpasteurized milk or other dairy products. Fruits and vegetables should be washed before consuming.

Cross-contamination of foods should be avoided.

Uncooked meats should be kept separate from produce, cooked foods, and ready-to-eat foods. Hands, cutting boards, counters, knives, and other utensils should be washed thoroughly after handling uncooked foods. Hands should be washed before handling any food, and between handling different food items.

People who have salmonellosis should not prepare food or pour water for others until they have been shown to no longer be carrying the Salmonella bacterium.

People should wash their hands after contact with animal feces. Since reptiles are particularly likely to have Salmonella, everyone should immediately wash their hands after handling reptiles.

References and Additional Information


Health Infectious Diseases