The Multnomah County Health Department is investigating a laboratory-confirmed cluster of Salmonella infections linked to a conference in Portland from June 23 to 26, 2015.

Salmonella bacteria (red)/National Institute of Allergy and Infectious Diseases (NIAID)
Salmonella bacteria (red)/National Institute of Allergy and Infectious Diseases (NIAID)

Health officials have tallied 53 people who became ill, including nine laboratory-confirmed cases. They were participants attending an Open Source Bridge Conference at the Eliot Center in downtown Portland.

The Health Department is working to identify the source of the Salmonella that caused the illness. This complex investigation includes determining the cause from about 100 different food dishes prepared through multiple catering sources and served over a four-day period to about 500 people.

Deputy Health Officer Dr. Jennifer Vines says there is no indication at this time that this outbreak spread beyond the conference participants.

“We believe this was an isolated event that did not occur beyond the conference,’’ said Vines. “We are monitoring illness in Oregon to assure that this is the case.” Other states and the Centers for Disease Control have also been informed.

Conference organizers are working with health officials to identify ill people and what they ate in the days before becoming ill. The public health investigation includes collecting survey information from 223 conference participants, and conducting laboratory testing of Salmonella from people affected. Information from the investigation is used to take steps that will prevent related illnesses from occurring.

Salmonella is a bacteria that causes people to develop diarrhea, fever and abdominal cramps. Most people start getting sick one to three days after infection, though that can vary from 12 hours to 7 days. It is common for people to be ill for four to seven days, and recover without treatment. The elderly, infants and people with an impaired immune system are more likely to have a severe illness.

Large outbreaks of Salmonellosis have been linked to produce like bean sprouts and cantaloupes, and to poultry and poultry products. As with all foodborne illnesses, outbreaks can also occur when there are breaches in good food-handling practices.

The Centers for Disease Control and Prevention estimate about 1.2 million cases of salmonella infection occur every year in the United States.

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