Source of major German E. coli outbreak remains a mystery

A deadly E. coli outbreak in Germany remains unsolved despite more than 400 people falling ill and three deaths.

In August 2025, an outbreak caused by enterohemorrhagic E. coli (EHEC) was detected. Most cases occurred in the north and west of the country. Children younger than 10 years old were mainly affected, some developing hemolytic uremic syndrome (HUS), a serious systemic complication of E. coli infection, which can lead to kidney failure, brain damage and death.

The pathogen was identified as E. coli O45:H2. This type of E. coli is rare in Germany. From January 2015 to June 2025, it was only detected 13 times and these isolates are not genetically closely related to the outbreak strain.

German officials said the outbreak is very likely foodborne but despite extensive efforts, the specific sources of infection have not yet been identified. Investigations into the cause are ongoing. This includes surveying patients and their parents by phone, conducting a case-control study and analyzing shopping receipts. 

Past the peak
There are 199 confirmed illnesses, of which 53 are HUS cases. There are also nine probable and 220 possible outbreak cases. This means 428 infections are connected to the outbreak.

The previous total was 351 patients with 183 confirmed infections and 48 HUS cases.

Two confirmed cases have died: a 5-to 10-year-old patient with HUS and a 70- to 80-year-old female infected by E. coli. One probable case: a female patient older than 90 has also died.

Confirmed cases fell ill between Aug. 11 and Oct. 16. The median age of these cases is 4 with a range of less than 1 to 94 years old. All HUS patients are children. Authorities said the rate of reported cases appears to be slowing down.

The most affected states remain Mecklenburg-Vorpommern and Nordrhein-Westfalen. Nine of 16 federal states have four or more outbreak cases.

The Robert Koch Institute (RKI) received information on four travel-related outbreak cases. A U.S. woman had been in Mecklenburg-Vorpommern before falling sick, a child from the Netherlands had been shopping for food in Germany, a child living in Germany became ill in Italy, and a child from Luxembourg became ill with no evidence of exposure in Germany.

The incident is the largest since the E. coli O104 outbreak in 2011, which was associated with the consumption of fenugreek sprouts. The final case count in that outbreak was 4,075, including 908 HUS cases and 50 deaths in 16 countries.

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