Salmonella are bacteria that cause intestinal illness (salmonellosis) in humans, usually because they have eaten contaminated food. Salmonella bacteria normally live in the intestinal tracts of animals and birds. Contaminated foods are often of animal origin, such as beef, poultry, milk or eggs. But all foods, including fruits and vegetables, can become contaminated. Approximately 6,000 to 12,000 cases of Salmonella are reported in Canada each year. Because many milder cases are not diagnosed or reported, or are believed to be the "stomach flu," the actual number of infections is estimated to be many times more. Young children, seniors and those with weakened immune systems from diseases such as AIDS, or as a result of some cancer treatments, are the most vulnerable. The disease is more common in summer than in winter.

Typical symptoms include the sudden onset of headache, abdominal pain, diarrhea, fever, nausea and sometimes vomiting. Dehydration, especially among infants or in the elderly, may be severe. Although deaths are uncommon, the infection is more dangerous when it occurs in young children, the elderly, the debilitated and those with weakened immune systems. In these persons, the infection may spread from the intestines to the bloodstream and then to other body sites. Prompt treatment with antibiotics is important at this stage.

Persons with diarrhea usually recover completely, although it may be several months before their bowel habits are entirely normal. A small number of persons who are infected with Salmonella will go on to develop pain in their joints, irritation of the eyes and painful urination. This is called Reiter's syndrome. It can last for months or years, and can lead to chronic arthritis, which is difficult to treat. Antibiotic treatment does not make a difference in whether or not the person develops arthritis.

Symptoms start from 6 - 72 hours after exposure to Salmonella, average 12 - 36 hours.

Contaminated foods, such as raw meat, poultry and eggs that have not been cooked properly, are the most common source of the disease. Contaminated foods usually look and smell normal. Many raw foods of animal origin are frequently contaminated, but fortunately thorough cooking kills Salmonella. Not washing fresh fruits and vegetables before eating them, as well as not thoroughly cleaning work surfaces used to prepare raw meat and other foods in the kitchen can also expose you to Salmonella. Food can also be contaminated by food handlers who do not thoroughly wash their hands with soap after handling raw meat or after using the bathroom.

Persons with Salmonella infection shed the organism in their stool. Therefore, person-to-person transmission can also occur by the fecal-oral route through improper handwashing. Food may also become contaminated by the unwashed hands of an infected foodhandler who forgot to wash their hands with soap after using the bathroom.

Salmonella can be found in the feces of some pets, especially those with diarrhea. Exotic pets, such as snakes, turtles and reptiles, may carry Salmonella even when healthy. People can become infected if they do not wash their hands after contact.

Persons infected with Salmonella continue to shed the bacteria in their stool throughout the course of the infection, usually several days to several weeks. A person may be a carrier of the bacteria for months, especially in children. Depending on the type of Salmonella, approximately 1% of infected adults and 5% of children under the age of 5 shed the organism in their stool for up to 1 year.

Because many different illnesses cause the same symptoms as Salmonella, the only way to diagnose it is through laboratory tests on the stools of infected people.

Once Salmonella has been identified, further testing can determine the type of Salmonella and the appropriate antibiotics to use in treatment. For uncomplicated cases, there is no specific treatment except rehydration and electrolyte replacement with oral rehydration solution.

Antibiotics may not eliminate the carrier state and may lead to resistant strains or more severe infections. However, infants under 2 months of age, the elderly, the debilitated, those with sickle cell disease, persons infected with HIV or persons with continued high fever or other symptoms should be given antibiotic therapy. In adults, ciprofloxacin is highly effective but its use is not approved for children; ampicillin or amoxicillin may also be used.

• Thorough handwashing is the best prevention. Make sure hands are properly washed with soap and water after using the toilet, or before preparing foods (especially poultry and raw meats); be particularly careful with foods prepared for infants, elderly or immune compromised persons.
• Contaminated foods may look and smell normal. Thoroughly cook foods to destroy the bacteria.
• Do not eat raw or undercooked eggs, poultry or meat. Remember raw eggs are contained in 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. If you are served undercooked food in a restaurant, send it back.
• Prevent cross contamination in the kitchen:
  • use separate cutting boards for foods of animal origin (raw meats) and other foods.
  • carefully clean all cutting boards, countertops and utensils with soap and hot water after preparing raw food of animal origin.
• Avoid raw or unpasteurized milk and other dairy products. Mother's milk is the safest food for infants.
• Thoroughly wash fruits and vegetables before eating them.
• When buying and storing groceries, keep meats separate from fruits, vegetables, cooked foods and ready-to-eat foods.
• Because bacteria grow quickly at room temperature, go directly home from grocery shopping and refrigerate or freeze food immediately.
• Always defrost food in the refrigerator, in cold water or in the microwave, never at room temperature. Set your refrigerator to 4 degrees C (40 degrees F) and your freezer to -18 degrees C (0 F).
• Wash your hands before handling any food. Be sure to wash your hands, cutting boards, counters, knives and other utensils after preparing uncooked foods.
• Wash your hands after contact with animal feces, for example, after changing the kitty litter or scooping up after your dog.
• Since reptiles can have Salmonella, always wash your hands after handling them. Reptiles, including turtles, are not appropriate pets for children and should not be in the same house as an infant.
• Infected children, health care workers or foodhandlers should be excluded from daycare/work until 24 hours after diarrhea stops; proper hygiene and handwashing habits should be stressed for carriers who have no symptoms.
• If you are diagnosed with Salmonella, be sure that you or your doctor informs the local Public Health Department. If many cases occur at the same time, it may mean that a restaurant or a particular food item has a problem that needs to be corrected.