Source of major German E. coli outbreak remains a mystery

A deadly outbreak of E. coli 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 under the age of 10 have been primarily affected, with 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 detected only 13 times and these isolates are not genetically closely related to the outbreak strain.

German authorities have said the outbreak was most likely foodborne, but despite considerable efforts, the specific sources of the infection have not yet been identified. Investigations into the cause are ongoing. This includes a telephone survey of patients and their parents, conducting a case-control study and analyzing purchase receipts.

Past the summit
There are 199 confirmed cases, including 53 cases of HUS. There are also nine probable cases and 220 possible cases. This means that 428 infections are linked to the outbreak.

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

Two confirmed cases died: a patient aged 5 to 10 years old with HUS and a woman aged 70 to 80 years old infected with E. coli. A probable case: a patient over 90 years old also died.

The confirmed cases fell ill between August 11 and October 16. The median age of these cases is 4 years with a range of less than 1 to 94 years. All HUS patients are children. Officials said the rate of reported cases appeared to be slowing.

The most affected states remain Mecklenburg-Western Pomerania and Nordrhein-Westfalen. Nine of the 16 federal states have at least four cases of epidemics.

The Robert Koch Institute (RKI) has received information on four travel-related outbreak cases. An American woman had traveled to Mecklenburg-Vorpommern before becoming ill, a child from the Netherlands was shopping in Germany, a child living in Germany became ill in Italy, and a child from Luxembourg became ill without any evidence of exposure in Germany.

This is the largest incident since the E. coli O104 in 2011, associated with the consumption of fenugreek shoots. The final number of cases in this outbreak was 4,075, including 908 HUS cases and 50 deaths in 16 countries.