The CDC, FDA, Department of Agriculture and state public-health officials are working together to determine the cause of an ongoing salmonella outbreak that has affected people in 42 states.

As of Friday, 399 cases of infection were reported between Sept. 3 and Dec. 31, with most illnesses beginning after Oct. 1. Eighteen percent of patients were hospitalized.

Salmonella 101

Salmonella is a group of bacteria that can cause diarrheal illness in humans. The microscopic bacteria pass from the feces of people or animals to other people or animals.

Most patients develop diarrhea, fever and abdominal cramps 12 to 72 hours after infection. The illness usually lasts 4 to 7 days, and most patients recover without treatment.

In some patients, however, the diarrhea may be so severe that hospitalization is required, and the infection may spread from the intestines to the bloodstream, and then to other body sites. In such cases, death can occur if the patient fails to receive a prompt course of antibiotics. The elderly, infants and those with impaired immune systems are more likely to have a severe illness. Some salmonella bacteria have become resistant to antibiotics, largely as a result of their use to promote the growth of food animals—a practice organic consumers decry.

Patients with diarrhea usually recover completely, although it may be several months before their bowel habits are entirely normal. A small number develop joint pain, eye irritation and painful urination—a condition known as Reiter’s syndrome. It can last for months or years and can lead to chronic arthritis that’s difficult to treat.

Progress Report

Agencies are working to identify the specific contaminated product—probably a food or foods—responsible for this outbreak. Outbreaks from a widely distributed contaminated product may cause illnesses across the United States, and the identity of the contaminated product is often not readily apparent.

In outbreaks like this one, identification of the contaminated product requires conducting detailed standardized interviews with individuals who were ill, as well as with non-ill members of the public, to compare foods they recently ate and other exposures.

Preventing Infection

There is no vaccine to prevent salmonella infection. You can, however, take preventive steps:

  • Don’t 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. If you are served undercooked meat, poultry or eggs in a restaurant, don’t hesitate to send your plate back to the kitchen for further cooking.
  • Don’t 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. Hands should be washed before handling food and between handling different food items.
  • Those infected with salmonella should not prepare food or pour water for others until their diarrhea has resolved. Many health departments require restaurant workers with salmonella infection to have a stool test showing they no longer carry the bacterium before they return to work.
  • Be particularly careful with foods prepared for infants, the elderly and the immunocompromised. Don’t work with raw poultry or meat and an infant (e.g., feeding, changing diapers) at the same time. Mother’s milk is the safest food for young infants. Breastfeeding prevents salmonella infection and many other health problems.
  • Wash your hands after contact with animal feces. Because reptiles are particularly likely to have salmonella, which can contaminate their skin, people should wash their hands immediately after handling reptiles. Reptiles (including turtles) are not appropriate pets for small children and should not be in the same home as an infant.
  • Salmonella carried in the intestines of chicks and ducklings contaminates their environment and the animal’s entire surface area. 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. Wash hands immediately after touching birds, including baby chicks and ducklings, or their environment.

Editor’s Note: We last reported on salmonella in August. For information on the summer outbreak linked to jalapeño and serrano peppers (and originally blamed on tomatoes), click here.

Photo courtesy of the CDC