Escherichia coli, usually shortened to E. coli, is commonly found in the intestines of people and warm-blooded animals. WHO explains that most strains are harmless. Some strains produce Shiga toxins and can cause severe foodborne disease; these are called Shiga toxin-producing E. coli, or STEC.
How is STEC different from harmless E. coli?
The term E. coli covers many strains. Finding the name in a report or article does not automatically mean the strain causes severe disease. STEC strains are distinguished by their production of Shiga toxins. WHO identifies O157:H7 as an important STEC serotype, while noting that other serotypes also cause sporadic illness and outbreaks.
What symptoms does WHO describe?
STEC illness can cause abdominal cramps and diarrhoea that may progress to bloody diarrhoea. Fever and vomiting can also occur. WHO gives an incubation range of 3–8 days, with a median of 3–4 days. Most patients recover within 10 days.
Symptoms alone cannot show which organism caused an illness. Bloody diarrhoea or severe abdominal cramps require medical care, according to WHO.
Why are young children highlighted?
A small proportion of people with STEC infection develop haemolytic uraemic syndrome, or HUS. WHO states that this life-threatening complication occurs particularly in young children and older people.
HUS is characterized by acute kidney failure, haemolytic anaemia and a low platelet count. WHO estimates that up to 10% of people with STEC infection may develop HUS. That estimate describes groups of patients and cannot predict the risk for a particular child.
What does WHO say about antibiotics?
WHO states that antibiotics are not part of treatment for STEC disease and may possibly increase the risk of HUS. This point is specific to suspected or confirmed STEC disease; it should not be generalized to every bacterial infection.
Families should not start, stop or change prescription medicines on the basis of this page. Bloody diarrhoea and severe abdominal pain need professional assessment so the clinician can consider the possible cause and appropriate care.
How can people be exposed?
WHO identifies contaminated food as a primary route. Examples include raw or undercooked ground meat, raw milk, and raw vegetables or sprouts contaminated with faecal material. Cross-contamination can occur through meat, surfaces and kitchen utensils during food preparation.
Waterborne spread has been reported through contaminated drinking water and recreational water. Person-to-person spread can occur through the faecal-oral route. WHO also identifies direct contact with farm animals as a risk factor. Children may excrete the organism for longer than adults even when symptoms are no longer obvious.
Does thorough cooking help?
STEC is sensitive to heat. WHO says food should be cooked thoroughly so that all parts reach at least 70 degrees Celsius. Heating methods such as cooking or pasteurization are effective ways to eliminate STEC from contaminated food.
Cooking one item does not prevent contamination of ready-to-eat food through unwashed hands, surfaces or utensils. Food safety therefore involves the whole preparation sequence.
What are WHO’s five keys to safer food?
- Keep clean.
- Separate raw and cooked food.
- Cook thoroughly.
- Keep food at safe temperatures.
- Use safe water and raw materials.
WHO also recommends careful washing of fruits and vegetables, particularly when they will be eaten raw. Vulnerable groups including small children should avoid raw or undercooked meat, raw milk and products made from raw milk.
Why does handwashing matter?
WHO recommends regular handwashing before preparing or eating food and after using the toilet. It highlights handwashing for people caring for small children, older people or people with weakened immune systems because STEC can spread through food, water, animal contact and person-to-person contact.
Why are several prevention routes listed?
WHO’s account shows that STEC prevention is broader than avoiding one food. Contamination can occur during production, through water, during food preparation, through animal contact or between people. Keeping clean, separating raw and cooked items, cooking thoroughly, controlling temperature and using safe water address different points along those routes.
Public-health control also operates before food reaches a household. WHO describes hygiene education for workers, controls during farming and slaughter, food-safety standards and surveillance as parts of prevention. Household measures reduce exposure but cannot identify the source of an individual illness or confirm that a particular product caused it.
When should medical care be sought?
WHO specifically advises medical care for bloody diarrhoea or severe abdominal cramps. Prompt assessment is also appropriate when a child is becoming less responsive, cannot keep fluids down, urinates much less than usual, appears dehydrated or is otherwise worsening. Collapse, breathing difficulty, seizure or other signs of critical illness require emergency care.
What does the incubation period mean?
WHO gives a 3–8 day incubation range, with a median of 3–4 days. The incubation period is the interval between exposure and the beginning of symptoms. It can help public-health teams investigate possible sources, but it cannot identify a particular food or contact by itself.
Because several exposures may occur during that interval, assumptions based on the most recent meal can be misleading. Laboratory and outbreak investigations use additional information to identify the organism and any shared source.
Why can children remain relevant to transmission after symptoms improve?
WHO reports that an asymptomatic carrier state can occur and that STEC may be excreted for longer in children than in adults. A child may therefore appear better while infection-control questions remain relevant, particularly in households and group settings.
Requirements for returning to childcare or school depend on local public-health rules and the individual situation. Families should follow instructions from the clinician or health authority managing the case rather than relying on a general duration from this page.
References
- World Health Organization. E. coli, 7 February 2018. Source reviewed 4 October 2026.