From the Center for Disease Control and Prevention (CDC)
Every year, Salmonella is estimated to cause one million foodborne illnesses in the United States, with 19,000 hospitalizations and 380 deaths. Most persons infected with Salmonella develop diarrhea, 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.
What is Salmonella?
Salmonella is a bacteria that makes people sick. It was discovered by an American scientist named Dr. Salmon, and has been known to cause illness for over 125 years.
Most people infected with Salmonella develop diarrhea, fever, and abdominal cramps between 12 and 72 hours after infection. The illness usually lasts 4 to 7 days, and most individuals recover without treatment. In some cases, 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. In these cases, Salmonella 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 Common is Salmonella Infection?
CDC estimates that approximately 1.2 million illnesses and approximately 450 deaths occur due to non-typhoidal Salmonella annually in the United States. Read more key Salmonella statistics.
There are many different kinds of Salmonella bacteria. Salmonella serotype Typhimurium and Salmonellaserotype Enteritidis are the most common in the United States3. Salmonella infections are more common in the summer than winter. Learn more about Salmonella serotypes.
Who is at Highest Risk for Salmonella Infection?
Children are at the highest risk for Salmonella infection. Children under the age of 5 have higher rates of Salmonella infection than any other age group. Young children, older adults, and people with weakened immune systems are the most likely to have severe infections.
Are there Long-Term Consequences to a Salmonella Infection?
People with diarrhea due to a Salmonella infection usually recover completely, although it may be several months before their bowel habits are entirely normal.
A small number of people with Salmonella develop pain in their joints. This is called reactive arthritis. Reactive arthritis can last for months or years and can lead to chronic arthritis, which can be difficult to treat. Antibiotic treatment of the initial Salmonella infection does not make a difference in whether or not the person develops arthritis. People with reactive arthritis can also develop irritation of the eyes and painful urination.
Diagnosis and treatment
How Can Salmonella Infections Be Diagnosed?
Diagnosing salmonellosis requires testing a clinical specimen (such as stool or blood) from an infected person to distinguish it from other illnesses that can cause diarrhea, fever, and abdominal cramps. Once Salmonella is identified in the specimen, additional testing can be done to further characterize the Salmonella.
Steps in Laboratory Testing and Reporting Salmonella
- Laboratory scientists identify Salmonella infection by culturing a patient’s sample. If Salmonella bacteria grow, then the diagnosis is confirmed, or in laboratory-terms, “culture confirmed.”
- Clinical diagnostic laboratories report the test results to the treating clinician and submit Salmonella isolates to state and territorial public health laboratories for serotyping and DNA fingerprinting.
- The public health laboratories report the results to CDC’s Laboratory-based Enteric Disease Surveillance and toPulseNet
- The public health laboratories forward atypical serotypes to CDC’s National Salmonella Reference Laboratory for more characterization or confirmation.
Serotype: group within a single species of microorganisms, such as bacteria or viruses, which share distinctive surface chemical structures
Culture: Growing bacteria, viruses, and other living matter in a specific environment, such as a petri dish coated with nutrients to encourage growth
Salmonella are divided into serotypes according to structures on the bacteria’s surface. Serotyping is used in outbreak investigations to link cases of illness with similar bacteria and track them to the source (example: a contaminated food or an infected animal). Some serotypes are only found in one kind of animal or in a single place. Others are found in many different animals and all over the world. Some serotypes can cause especially severe illnesses when they infect people; most typically cause milder illnesses.
Serotyping has played an important role in the understanding the epidemiologic and molecular characterization of Salmonella for decades. Today, modern genetic subtyping methods provide scientists with additional information to understand common serotypes and identify, investigate, and trace outbreaks.
Quick Tips for Preventing Salmonella
- Cook poultry, ground beef, and eggs thoroughly. Do not eat or drink foods containing raw eggs, or raw (unpasteurized) milk.
- If you are served undercooked meat, poultry or eggs in a restaurant, don’t hesitate to send it back to the kitchen for further cooking.
- Wash hands, kitchen work surfaces, and utensils with soap and water immediately after they have been in contact with raw meat or poultry.
- Be particularly careful with foods prepared for infants, the elderly, and the immunocompromised.
- Wash hands with soap after handling reptiles, birds, or baby chicks, and after contact with pet feces.
- Avoid direct or even indirect contact between reptiles (turtles, iguanas, other lizards, snakes) and infants or immunocompromised persons.
- Don’t work with raw poultry or meat, and an infant (e.g., feed, change diaper) at the same time.
- Mother’s milk is the safest food for young infants. Breastfeeding prevents salmonellosis and many other health problems.
More About Prevention
There is no vaccine to prevent salmonellosis. Because 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 homemade 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. Produce should be thoroughly washed.
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 touching uncooked foods. Hand should be washed before handling food, and between handling different food items.
People who have salmonellosis should not prepare food or pour water for others until their diarrhea has resolved. Many health departments require that restaurant workers with Salmonella infection have a stool test showing that they are no longer carrying the Salmonella bacterium before they return to work.
People should wash their hands after contact with animal feces. Because reptiles are particularly likely to have Salmonella, and it can contaminate their skin, everyone should immediately wash their hands after handling reptiles. Reptiles (including turtles) are not appropriate pets for small children and should not be in the same house as an infant. Salmonella carried in the intestines of chicks and ducklings contaminates their environment and the entire surface of the animal. Children can be exposed to the bacteria by simply holding, cuddling, or kissing the birds. Children should not handle baby chicks or other young birds. Everyone should immediately wash their hands after touching birds, including baby chicks and ducklings, or their environment.
Some prevention steps occur everyday without you thinking about it. Pasteurization of milk and treatment of municipal water supplies are highly effective prevention measures that have been in place for decades. In the 1970s, small pet turtles were a common source of salmonellosis in the United States, so in 1975, the sale of small turtles was banned in this country. However, in 2008, they were still being sold, and cases of Salmonella associated with pet turtles have been reported. Improvements in farm animal hygiene, in slaughter plant practices, and in vegetable and fruit harvesting and packing operations may help prevent salmonellosis caused by contaminated foods. Better education of food industry workers in basic food safety and restaurant inspection procedures may prevent cross-contamination and other food handling errors that can lead to outbreaks. Wider use of pasteurized egg in restaurants, hospitals, and nursing homes is an important prevention measure. In the future, irradiation or other treatments may greatly reduce contamination of raw meat.