According to the U.S. Centers for Disease Control, this outbreak appears to be over. However, Salmonella remains an important cause of human illness in the United States.
A total of 907 people infected with the outbreak strains of Salmonella Poona were reported from 40 states.
A total of 204 ill people were hospitalized, and six deaths were reported from Arizona (1), California (3), Oklahoma (1), and Texas (1). Salmonella infection was not considered to be a contributing factor in two of the three deaths in California.
Epidemiologic, laboratory, and traceback investigations identified cucumbers imported from Mexico and distributed by Andrew & Williamson Fresh Produce as the likely source of the infections in this outbreak.
Two recalls of cucumbers that may be contaminated with Salmonella were announced in September 2015 as a result of this investigation: Andrew & Williamson Fresh Produce and Custom Produce Sales.
Investigation of illnesses that were reported after the peak of the outbreak in August and September 2015 did not identify an additional food linked to illness. The source of contamination for the cucumbers distributed by Andrew & Williamson Fresh Produce has not been identified.
Among people for whom information was available, illnesses started on dates ranging from July 3, 2015 to February 29, 2016. Ill people ranged in age from less than 1 year to 99, with a median age of 18. Forty-nine percent of ill people were children younger than 18 years. Fifty-six percent of ill people were female. Among 720 people with available information, 204 (28%) were hospitalized. Six deaths were reported.
WGS showed that isolates from ill people were closely related genetically. These results also included isolates from people who became ill in October, November and January after the outbreak’s peak. This close genetic relationship means that people in this outbreak were more likely to share a common source of infection, such as a contaminated food.
Several state health and agriculture departments collected and tested cucumbers from retail locations and isolated the outbreak strains of Salmonella Poona. Information indicated that these cucumbers were distributed by Andrew & Williamson Fresh Produce. Additionally, testing of cucumbers collected from the Andrew & Williamson Fresh Produce facility isolated the outbreak strains of Salmonella Poona.
WGS of Salmonella Poona isolates from ill people and from contaminated cucumbers distributed by Andrew & Williamson Fresh Produce showed that the strains were closely related genetically. This close genetic relationship provided additional evidence that ill people in this outbreak became ill from consuming cucumbers distributed by Andrew & Williamson.