An E. coli outbreak linked to undercooked burgers at restaurants in four states has sickened at least 11 people, according to the Centers for Disease Control and Prevention (CDC). As health officials try to determine which cases may be part of the outbreak, they’ll be asking those who became ill to remember what they ate during the past week.
E. coli symptoms, which include diarrhea that is sometimes bloody and abdominal cramping, usually take about three days after exposure to develop but can take as long as eight days. Many people tend to think that the thing that made them sick was the last thing they ate before they started having symptoms, but that’s often not the case.
Outbreak investigations have two parts, identifying all of the people who are part of the outbreak and determining the source. Bacteria strains have their own genetic fingerprint, so the E. coli strain in this outbreak has a different fingerprint than the E.coli strain that caused the Trader Joe’s/Glass Onion salad outbreak or the Federico’s outbreak which both happened last fall.
A lab test called a pulsed field gel electrophoresis (PFGE) performed on a stool sample identifies the bacterial fingerprint. Health departments in different states can post and view these fingerprint images on a special network to see which cases are a match. That’s how they’ve determined the 11 cases identified so far in this outbreak. If you want to know if you’re illness is part of an outbreak, you have to submit a stool sample for testing.
The second piece of the investigation is the identifying the source. This is accomplished by interviewing those who became ill and having them complete a detailed food history. Foods that are repeatedly identified are potential sources. In this outbreak, rare hamburgers served at different restaurants were identified by all 11 people. This suggested that the meat was contaminated when it arrived at the restaurants. Authorities then did traceback investigation to discover if there was a common supplier. In this case, the answer was yes, Wolverine Packing Company of Detroit which yesterday issued a recall for 1.8 million pounds of meat that was distributed nationwide.
Given the size and scope of the recall it’s likely that more illnesses will be reported. And, because the recall was not issued until yesterday, some people who ate contaminated beef may not be sick until next week. If you have symptoms, see a doctor and mention your possible exposure to E.coli as antibiotic treatment makes E.coli infections worse.