The Centers for Disease Control and Prevention (CDC) is investigating the source of an E.coli outbreak that is spreading across the Midwest.
As of August 17, 29 illnesses, 10 hospitalizations, and zero deaths have been reported, according to the latest investigation. To avoid getting sick, health experts recommend washing all foods and countertops well and cooking meat thoroughly.
“This outbreak is associated with a particular subtype of E. coli that can cause abdominal pain, vomiting, and bloody diarrhea. If someone believes they have contracted this infection, they should seek medical attention to have it confirmed and for supportive care,” said Dr. Amesh Adalja a senior scholar at the Johns Hopkins University Center for Health Security and an infectious disease expert.
In an update posted on August 19, CDC officials reported that 22 of the 26 people interviewed by health officials had recently eaten at Wendy’s the week before they became ill. Officials said most sick people reported eating a sandwich with romaine lettuce at the restaurant. Wendy’s is taking precautionary measures and removing the romaine lettuce being used for sandwiches in that region, according to the CDC. Salads are not being affected because they use a different type of romaine lettuce.
CDC officials stressed that they are not advising people to stop eating at Wendy’s restaurants or to stop eating romaine lettuce. Most strains of E. coli are harmless, however, certain strains can produce a toxin called Shinga toxin.
Approximately 265,000 STEC infections occur in the United States each year. According to the CDC, STEC causes an estimated 3,600 hospitalization and 30 deaths annually. It typically takes a few weeks for a case to be linked back to an outbreak. Many cases likely go unreported in an outbreak since many people with E.coli infections do not seek medical care.
The food source behind the current outbreak is unknown and it may take several weeks before the food source is identified, says Adalja. Sometimes the source of an E.coli outbreak is never identified, says Dr. Nupur Garg, an emergency physician in North Haven, CT. Contaminated produce and meat are the typical sources of E.coli outbreaks, Garg added.
“The ultimate source is usually fecal contamination of some food product. This could be some sort of vegetable, ground beef, or a fruit,” says Adalja.
Parvathy Sukumaran 
