September 12, 2025, 2:05 am | Read time: 8 minutes
In May 2011, a severe health emergency was declared in Germany. Nearly 4,000 people fell ill, and 53 lost their lives.1 The cause: certain bacteria—Enterohemorrhagic E. coli (EHEC for short)—that produce toxins and can cause acute intestinal inflammation. What you should know about the symptoms, transmission, and causes.
The Actual Role of Escherichia coli in the Body
The bacterium Escherichia coli (E. coli) plays important roles in the human gut, such as breaking down nutrients or protecting against pathogens. However, if it enters the body outside the digestive tract, it becomes an indicator of fecal contamination, such as in drinking water or food. Especially in people with weakened immune systems—such as infants or the elderly—E. coli bacteria can cause serious infections, including urinary tract infections, wound infections, peritonitis, gallbladder or lung infections, meningitis, or even sepsis.
In contrast, EHEC bacteria naturally occur in the intestines of ruminants like cattle, sheep, or deer. They can produce highly potent cell toxins that can lead to severe health issues in humans. These specific bacteria belong to the group of Shiga toxin- or Verotoxin-producing Escherichia coli (STEC/VTEC). Even a small amount is enough to trigger an infection—sometimes with drastic outcomes.2
What Happened in 2011?
The EHEC outbreak in 2011 is considered the most severe in Germany to date. For the first time, infections occurred on such a scale that not only was the national health system heavily challenged, but it also drew international attention—particularly due to the unusually high number of HUS cases. More on that later. Fenugreek seeds from Egypt, used for sprout production, are considered the likely trigger. How exactly they became contaminated with the pathogen could not be clearly determined in retrospect.
Symptoms: How an EHEC Infection Manifests
An EHEC infection can be completely asymptomatic—but it can also cause serious symptoms. Typically, the first signs appear two to ten days after infection. Common symptoms include watery diarrhea, nausea, vomiting, and abdominal pain. Fever is rare.
In some patients, the condition worsens: The diarrhea becomes bloody, the abdominal pain more intense, and occasionally, fever occurs. These severe forms primarily affect young children, the elderly, or people with weakened immune systems.
In about five to ten percent of symptomatic patients, the so-called hemolytic-uremic syndrome (HUS) develops a few days after the onset of diarrhea. This leads to the destruction of red blood cells, acute kidney function impairment, and blood clotting disorders—a life-threatening condition that mainly affects children.3
How EHEC is Transmitted
Transmission occurs primarily fecal-oral—that is, through the mouth after the bacteria have landed on food, hands, or objects. EHEC usually enters the environment through the feces of infected animals and can then reach humans in various ways. Even a few pathogens are enough to cause illness in the human body.
Animal Feces and Contaminated Food
Infection often occurs through the consumption of raw or insufficiently heated foods from raw milk and raw sausage products, vegetables, fruits, or seeds. Contact with ruminants—such as petting animals in a petting zoo—can also lead to transmission, even if the animals appear healthy. Smear infections via contaminated surfaces, toys, or kitchen utensils are also possible.4
Smear Infections
EHEC smear infections are possible through objects like kitchen utensils, contaminated surfaces, or directly from person to person. There is a risk of infection, especially for young children, in direct contact with animals: When petting, the bacteria can be transferred from hands to mouth.
Contaminated Water
There is also a risk of EHEC infection when swimming in lakes, as the bacteria can be present in contaminated water and ingested through the mouth. They can thrive particularly well in natural waters. In chlorinated swimming pools, however, infection is considered unlikely.
Why Children Are Particularly at Risk
Children are among the most at-risk groups for an EHEC infection. Their immune systems and organs are still developing, making them more sensitive to the toxins released by the pathogens. Complications like the hemolytic-uremic syndrome (HUS) occur much more frequently in them than in adults. Therefore, at the first signs such as severe abdominal pain or unusual bowel movements, medical advice should be sought immediately.
Complications: When EHEC Leads to HUS
If the toxins produced by EHEC bacteria spread beyond the intestines in the body, HUS can develop. The toxins primarily attack the walls of small blood vessels found throughout the body. HUS is therefore a condition that can affect multiple organs simultaneously. Typically, the disease first and most severely affects the kidneys and the gastrointestinal tract. But the brain and nerves, the pancreas, and the skeletal and heart muscles can also be affected.
As a result, serious long-term effects can develop, including high blood pressure or chronic kidney damage. In some children, insulin-dependent diabetes is also possible. Only in rare cases does permanent kidney damage remain, requiring ongoing dialysis.
Prevention: How to Avoid Infection
EHEC bacteria are resilient and can remain active in the environment for a long time. Since even the smallest amounts are enough to trigger an infection, consistent hygiene is the most important protection.
The following measures are considered particularly effective for prevention:
- Careful hand hygiene after contact with animals, such as in petting zoos or on farms–especially for young children, before they eat or put their hands in their mouths
- Thorough handwashing with soap—before eating, after using the toilet, and before and after preparing food
- If possible, avoid close contact with infected persons—especially among siblings
- Strict kitchen and food hygiene, especially with raw animal products
Special precautions are also required in the home environment of infected individuals:
- Thorough handwashing is essential after changing the diapers of infected children
- People with EHEC and their household members may only return to community facilities like daycares or schools once cleared by their treating doctors
- Infected individuals should use a separate toilet if possible
- Those working in food processing or communal catering may only resume work once no pathogens are detectable in their stool5
Causes and Symptoms of Food Poisoning
Meningitis: Causes, Symptoms and Treatment Options
How Can EHEC Be Treated?
There is currently no specific therapy for EHEC infection. Medical treatment, therefore, aims to stabilize the body and prevent complications.
The focus is on compensating for fluid and electrolyte losses—either by drinking or, if necessary, through infusions. Early intravenous fluid administration can help prevent or limit kidney damage. In severe cases, hospitalization is required.
If HUS occurs, kidney function is supported with medication. If that is not sufficient, dialysis may be necessary. Additionally, affected patients receive blood transfusions as needed to replace missing red blood cells, platelets, or plasma.
Current Situation in Germany
Recently, two children in the Oberhavel district (Brandenburg) contracted EHEC and required hospital treatment. Both were diagnosed with hemolytic-uremic syndrome (HUS)—a serious complication that can occur especially in childhood EHEC infections. Both are now showing significant improvement in their health.
A connection with the current EHEC outbreak in Mecklenburg-Vorpommern is being investigated. Since mid-August, a total of 16 confirmed cases have been registered there, including 13 children and three adults. HUS complications also occurred in five of the infected children. Additionally, investigations are underway for 28 other suspected cases. Furthermore, 44 people are under observation who may have come into contact with the pathogen in Mecklenburg-Vorpommern.6
The exact causes of the outbreak have not yet been clarified. The pathogen strain has been identified, but specific sources of infection are still being investigated.