EHEC:Sprouts trigger a crisis ten years ago

In the midst of the corona pandemic, the EHEC crisis has almost been forgotten. But there was great excitement and concern when, from May 2011, bloody diarrheal diseases began to appear, especially in northern Germany. Thousands get sick, 53 people die.

When the Berlin Robert Koch Institute (RKI) received frequent reports of diarrheal diseases due to EHEC infections at the beginning of May 2011, it didn't seem unusual at first. On average, around 1,000 people are infected with the germ every year. But it quickly becomes clear that this pathogen is more aggressive than others. Some of the diseases are very severe, and an unusually large number of patients suffer from a complication, haemolytic uraemic syndrome (HUS), which is associated with the destruction of blood cells and damage to the kidneys. In retrospect, the RKI dates the beginning of the disease wave to May 8th - on this day a woman from Lower Saxony fell ill due to an infection with the intestinal germ.

EHEC:An intestinal germ that produces toxins

EHEC means Enterohemorrhagic Escherichia coli. These are Escherichia coli bacteria that form cell toxins. EHEC germs always find their way into the human body - mostly through contaminated food. In most cases, the bacteria cause mild to severe diarrhea. However, these toxins can also cause serious, possibly even fatal diseases in humans. HUS can develop as a result of infection - a condition that causes blood clotting disorders and red blood cell destruction, leading to acute kidney failure.

Many young women are among those affected

More and more infections are being reported in May 2011, especially in Hamburg and Schleswig-Holstein. What is atypical is that there are many young women among those affected. Usually, however, EHEC tends to affect small children. On May 21, the Robert Koch Institute informed the Federal Office for Risk Assessment (BfR) and the Federal Office for Consumer Protection and Food Safety (BVL) about the increase in the number of diseases. Just one day later, the wave of diseases reached its peak:On this day, 161 new EHEC infections and 63 new HUS cases were reported. Shortly thereafter, the first deaths occur.

Cucumbers, lettuce and tomatoes suspected of being EHEC

Experts are puzzled about the cause of the bloody diarrhea. The usual suspects like raw meat and milk are quickly ruled out. When surveying the sick, it is noticeable that many of those affected remember that they had eaten lettuce before the infection. Tomatoes and cucumbers are also mentioned as possible sources of infection with the pathogen. On May 25th, there was a bang:RKI and BfR warn in a joint statement against the consumption of raw tomatoes, cucumbers and lettuce - especially in northern Germany. The next day, the Hamburg Hygiene Institute even found what they were looking for and tracked down EHEC pathogens on Spanish cucumbers. But the cucumber trail is wrong.

Studies at the BfR quickly show that the EHEC pathogens on the cucumbers are not of the same O104:H4 type as the bacteria responsible for the massive outbreak. But which foods are instead responsible for the diseases?

Patients with severe neurological disorders

More and more people are getting sick, especially in Hamburg. Some HUS patients suffer from severe neurological disorders and there is no specific treatment. "The hospital capacities were completely exhausted. All the beds were occupied because it went so quickly," former RKI President Reinhard Burger recalls the situation in the Hanseatic city. There are diseases not only in northern Germany, but also in other regions of Germany, in Scandinavia and even in the USA.

Sprouts as the cause - but where does the pathogen come from?

EHEC investigators in the federal states and at the Federal Institute for Risk Assessment meticulously collect delivery data for more than 90 foods, from Lollo Rosso salad to rosemary and sprouts. The next big bang follows on June 5th:The Lower Saxony Ministry of Health warns against the consumption of sprouts and refers to the evaluation of the flow of goods:There is a trail from the sick to a company in the Uelzen district. On June 10, proof of the suspicion was provided:for the first time, the aggressive bacteria of type O104:H4 were discovered in sprouts delivered to North Rhine-Westphalia, which came from an organic farm in Bienenbüttel. A family rescued the pack from the trash after two family members contracted EHEC.

The authorities then advise against eating raw sprouts, and earlier recommendations for cucumbers, tomatoes and lettuce are cancelled. But many questions remain unanswered - above all, how the pathogen got on or in the sprouts. Was fertilization the cause? Sewage sludge, polluted drinking water or even terrorism? The pathogen is not found in any of the samples taken by the investigators at the organic farm on the edge of the Lüneburg Heath. The EHEC germ is also never detected in an unopened pack of sprouts.

Cases in France bring crucial clue

When infections caused by the pathogen of type O104:H4 also occur in France, the EHEC investigators succeed in further narrowing down the suspicious food. Persons who had fallen ill near Bordeaux had eaten sprouts produced from three different types of seed at a French children's home. Fenugreek seeds from Egypt have now been identified as the cause of the wave of infections, because they were the only ones to be found both in the sprout mixture consumed in France and in the sprout mixtures of the horticultural farm in Lower Saxony, as the BfR writes in review of the outbreak.

For the EHEC investigators it is clear:Fenugreek seeds produced in Egypt in the winter of 2008/2009 are the link between the cases of the disease in Germany and France. Partial quantities of this batch were used for sprout production both in Bienenbüttel and in France.

Fenugreek seeds from Egypt identified as the cause

Now everything goes very quickly. At the beginning of July, the EU imposed an import ban on fenugreek seeds from Egypt. The dangerous pathogens got onto the seed there "with a high degree of probability". European authorities and even the World Health Organization (WHO) now advise against eating raw sprouts. On July 21, BfR, BVL and RKI limit the consumption recommendation to raw consumption of fenugreek seeds from Egypt and sprouts made from them.

Almost 3,000 EHEC and 855 HUS diseases

On July 26, the RKI officially declared the largest EHEC outbreak in Germany to date to be over:No new diseases have been reported from the federal states for three weeks now. The authorities registered a total of 3,842 cases of illness, 2,987 EHEC and 855 HUS diseases. Nationwide, 35 people have died as a result of HUS disease and another 18 from EHEC. It is not only the largest EHEC outbreak in the history of the Federal Republic - based on the number of HUS cases, the authorities are even talking about the largest outbreak worldwide.

Origin of the pathogen is still unknown

Where and how the seeds came into contact with the outbreak pathogen is still a mystery - as is where the pathogen originated and whether there might be an animal reservoir for it, as the RKI says. "Nobody knows if O104:H4 will come back one day."

The consumer organization Foodwatch does not consider the EHEC crisis to be fully resolved. Only a good ten percent of the cases of illness could have been traced back, the organization criticized in 2013:"At least 87 percent of all reported EHEC cases were filed without clarifying the cause of infection," the RKI confirmed.

False cucumber warning:Claim for damages against Hamburg

The EHEC outbreak not only had consequences for the company in Bienenbüttel, which from then on was fighting for survival. The crisis is also affecting many farmers, because sales of cucumbers, lettuce, tomatoes and other types of vegetables have at times plummeted drastically due to the false warning. The EU Commission puts the loss of income in the European Union alone at more than 800 million euros. The city of Hamburg is faced with a claim for damages from a Spanish vegetable trader:he is demanding 2.3 million euros from the city for the wrong cucumber warning. The dispute ended in 2017 with a settlement, as a result of which the city paid a mid-six-figure sum.