Outbreak Investigation Updates by Date
Posted September 13, 2019 at 4:00 PM ET
This outbreak appears to be over. Shiga toxin-producing Escherichia coli (STEC) is an important cause of illness in the United States. Find more information about steps you can take to reduce your risk of infection on the E. coli and Food Safety web page.
CDC, public health and regulatory officials in several states, the U.S. Food and Drug Administrationexternal icon (FDA), and the Canadian Food Inspection Agency are investigating a multistate outbreak of E. coli O103 and E. coli O121 infections.
Public health investigators are using the PulseNet system to identify illnesses that may be part of this outbreak. PulseNet is the national subtyping network of public health and food regulatory agency laboratories coordinated by CDC. DNA fingerprinting is performed on E. coli bacteria isolated from ill people by using techniques called pulsed-field gel electrophoresis (PFGE) and whole genome sequencing (WGS). CDC PulseNet manages a national database of these DNA fingerprints to identify possible outbreaks. WGS gives a more detailed DNA fingerprint than PFGE. WGS performed on bacteria isolated from ill people showed that the bacteria were closely relatedly genetically. This means that people in this outbreak are more likely to share a common source of infection.
As of July 12, 2019, a total of 21 people infected with the outbreak strains of E. coli O103 (6 people), E. coli O121 (13 people), or both (2 people) have been reported from 7 states. A list of the states and the number of confirmed cases in each can be found on the Map of Reported Cases page.
Illnesses started on dates from March 18, 2019, to June 18, 2019. Ill people range in age from 6 to 79 years, with a median age of 25. Fifty-two percent of ill people are female. Of 17 people with information available, 8 (47%) have been hospitalized. No deaths and no cases of hemolytic uremic syndrome, a type of kidney failure, have been reported.
Illnesses that occurred after June 22, 2019, might not yet be reported due to the time it takes between when a person becomes ill with E. coli and when the illness is reported. This takes an average of two to three weeks.
Investigation of the Outbreak
Epidemiologic and traceback information indicate that ground bison produced by Northfork Bison Distributions, Inc., is the likely source of this outbreak.
In interviews, ill people answered questions about the foods they ate and other exposures in the week before they became ill. Of 9 people with available information, 6 (67%) people reported that they ate or maybe ate ground bison. Ill people ate ground bison in burgers from several different restaurants or prepared ground bison at home.
Regulatory officials collected records from the restaurants where ill people ate ground bison. These records showed that the ground bison produced by Northfork Bison Distributions, Inc., was sold in several restaurants where ill people ate ground bison.
On July 16, 2019, Northfork Bison Distributions, Inc. in Saint-Leonard, Quebec, Canada, recalled ground bison and bison patties (referred to as Bison Burgers and/or Buffalo Burgers) produced between February 22, 2019, and April 30, 2019. Consumers should not eat, and restaurants and retailers should not serve or sell, recalled ground bison products.
CDC will provide more information as it becomes available.