In late August 2017, the Centers for Disease Control and Prevention (CDC) announced that it was investigating an outbreak of Salmonella infections in 13 states that had sickened 37 people and led to 16 hospitalizations. The culprit? It was just a little thing: small turtles—those with shells less than 4 inches long—sold illegally by street vendors and at flea markets. It’s an extensive outbreak, given that the sale of small turtles as pets has been banned in the United States since 1975 because of the risk that they will transmit Salmonella.
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But Salmonella infections are not caused just by turtles. Backyard poultry, imported papayas, and microbiology labs have all been implicated in Salmonella outbreaks. As recently as July, a multistate outbreak of laboratory-associated Salmonella prompted the CDC to update their guidance for employers, clinicians, and teaching laboratories on avoiding Salmonella infections in those environments. Keep reading to find out why employers should be concerned about Salmonella infection and what the signs and symptoms are.
Sources of Salmonella
More than 1 million Americans each year develop salmonellosis, the bacterial infection caused by the various strains of Salmonella, and about 450 die. The disease causes diarrhea, fever, and abdominal cramps beginning from 12 to 72 hours after infection; the illness lasts about 4 to 7 days. Most victims recover without treatment, although some are hospitalized as a result of severe diarrhea. In patients who are that gravely affected by the disease, the infection can spread to the blood stream and other places in the body. Prompt treatment with antibiotics is required in those cases.
Most cases of salmonellosis result from the ingestion of contaminated food, like the four separate outbreaks associated with imported Maradol papayas in 2017, or the three-state outbreak associated with the consumption of Salmonella-contaminated eggs in 2016. Working with live animals is another common source of the disease, one that might affect employers in agriculture, zoos, and veterinary practices, as well as in research institutions. Most recently, however, the CDC is warning employers that operate microbiology laboratories to review their laboratory infection control practices.
Salmonella in Laboratories
Salmonella is present in many research laboratories, including clinical, commercial, and college and university teaching microbiology laboratories—where both staff and students may be exposed. The exposures are considered a public health problem, in addition to an occupational health problem, because the bacteria can sicken both people who work in laboratories and others who live in their households—even if they never visit the laboratory.
The 2017 outbreak, which occurred between March and June, sickened 24 people in 16 states. The strain identified in the outbreak, Salmonella Typhimurium, was closely genetically related to a strain that was identified in laboratory outbreaks in 2014 and 2011. After the 2011 outbreak, laboratory professionals developed guidelines for working safely with microorganisms in teaching laboratories—but many individuals who were sickened in the 2017 outbreak reported behavior that probably increased their risk of infection, including:
- Not wearing gloves or lab coats
- Not washing their hands
- Using the same writing utensils and notebooks outside the laboratory
Tomorrow we’ll look at CDC’s infection prevention recommendations for employees and students in microbiology laboratories.