E. coli outbreak investigation underway, several cases reported in Mesa County

Mesa County Public Health (MCPH) in coordination with the Colorado Department of Public Health and Environment (CDPHE) and the Centers for Disease Control and Prevention (CDC) are investigating an outbreak of Shiga toxin-producing E. coli (STEC) cases. As of October 22, 2024, 26 cases have been reported in Colorado, including several in Mesa County. One person in Mesa County has died in connection to the outbreak. This is an active investigation and more cases may emerge.

While the specific source of contamination is still under investigation, early information from the Food and Drug Administration indicates the onions on McDonald’s Quarter Pounders may be a source of this outbreak. Fresh-slivered onions are primarily used on Quarter Pounder hamburgers and not other menu items. USDA is also looking into the beef patties on the Quarter Pounder hamburgers. Based on case interviews and supplier information, McDonald’s has temporarily stopped producing the item in some states, including Colorado.

What is Mesa County Public Health doing

Our agency is working closely with CDPHE and CDC to monitor the situation. Our epidemiologists are conducting interviews of Mesa County residents who have tested positive for STEC, which includes gathering information about what they ate, where they ate, and if anyone else they know is also sick. Our Environmental Health team conducted investigations at specific restaurants and is working with restaurant management to ensure safety protocols are in place.

“We have local experts on hand with an efficient system in place to handle these situations. This helps with the speed of investigations to help prevent additional people from becoming sick,” said Erin Minnerath, Deputy Director at Mesa County Public Health. “The system remains in place for residents in Mesa County to have food that’s safe to eat.”

STEC background

Symptoms of STEC infections may include mild non-bloody diarrhea, bloody diarrhea, abdominal cramps, nausea, and vomiting. Symptoms typically begin three to four days after exposure but can begin between one to ten days. In some adults and young children, STEC infection may lead to hemolytic uremic syndrome (HUS), a potentially life-threatening complication. 

What consumers can do

• Reach out to your healthcare provider if you are experiencing STEC symptoms. 
• Do not prepare food for others while experiencing diarrhea.
• Practice good hand hygiene.

For more information

• Local updates: Sign up for health alerts from Mesa County Public Health on our website.
• Colorado updates: Learn about the state-level response and cases from the CDPHE website.
• Multi-state updates: Learn about the multi-state response and cases from the CDC website.