September 1, 2020
As of August 31, 2020, a total of 1,012 people infected with the outbreak strain of Salmonella Newport have been reported from 47 states. A list of the states and the number of cases in each can be found on the Map of Reported Cases page.
Illnesses started on dates ranging from June 19, 2020, to August 11, 2020. Ill people range in age from less than 1 to 102 years, with a median age of 40. Fifty-seven percent of ill people are female. Of 581 ill people with information available, 136 hospitalizations have been reported. No deaths have been reported.
Illnesses might not yet be reported due to the time it takes between when a person becomes ill and when the illness is reported. This takes an average of 2 to 4 weeks. Please see the Timeline for Reporting Cases of Salmonella Infection for more details.
Whole genome sequencing analysis of 732 bacterial isolates from ill people did not predict any antibiotic resistance in 730 isolates; one isolate had predicted resistance to ampicillin, and one isolate had predicted resistance to tetracycline. Standard antibiotic susceptibility testing of seven clinical isolates by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory showed no resistance. This resistance does not affect the choice of antibiotic used to treat most people.
Whole genome sequencing analysis shows that an outbreak of Salmonella Newport infections in Canadaexternal icon is related genetically to this outbreak in the United States. This means that people in both of these outbreaks are likely to share a common source of infection.
Investigation of the Outbreak
Epidemiologic and traceback pdf icon[PDF – 1 page] information indicates that red onions are a likely source of this outbreak. Due to the way onions are grown and harvested, other onion types, such as, white, yellow, or sweet yellow, are also likely to be contaminated.
In interviews, ill people answered questions about the foods they ate and other exposures in the week before they became ill. Ninety percent of people reported eating onions or foods likely containing onions in the week before their illness started. Of the 154 people who were asked what types of onions they ate, 103 (67%) ate red onions, 96 (62%) ate white onions, and 86 (56%) ate yellow onions. Most ill people reported eating more than one type of onion.
Many ill people were identified as part of illness clusters. An illness cluster is defined as two or more people who do not live in the same household who report eating at the same restaurant location, attending a common event, or shopping at the same location of a grocery store in the week before becoming ill. Investigating illness clusters can provide critical clues about the source of an outbreak. If several unrelated ill people ate or shopped at the same location of a restaurant or store within several days of each other, it suggests that the contaminated food item was served or sold there.
Thirty-four illness clusters have been identified in 13 states. Information was collected on 23 of the 34 clusters at restaurants and grocery stores. Information from these clusters shows that many ill people ate red onions and other types of onions. Investigations conducted by states and FDA determined that all 23 restaurants and grocery stores served or sold red, yellow, or white onions. Seventeen of the 23 (74%) served red onions, 13 (57%) served yellow onions, and 10 (43%) served white onions.
The traceback information collected from several of these illness clusters identified Thomson International, Inc., of Bakersfield, California, as a likely source of red onions. Due to the way onions are grown and harvested, other onion types, such as white, yellow, or sweet yellow, are also likely to be contaminated. Traceback is ongoing to determine if other onions are linked to the outbreak.
On August 1, 2020, Thomson International, Inc. voluntarily recalledexternal icon red, yellow, white, and sweet yellow onions because they may be contaminated with Salmonella.
Other companies have also recalled onions or foods made with recalled onions. See the full list of recalled products.
Consumers, restaurants, and retailers should not eat, serve, or sell recalled onions supplied by Thomson International, Inc., or any foods made with recalled onions.
CDC will provide updates when more information is available.