EHEC outbreak: 9 European countries report cases of haemolytic uraemic syndrome and enterohaemorrhagic E. coli infections
Austria, Denmark, Germany, the Netherlands, Norway, Spain, Sweden, Switzerland and the United Kingdom have reported cases of haemolytic uraemic syndrome (HUS) and/or bloody diarrhoea. HUS, which can lead to kidney failure, is a complication of an infection by particular Escherichia coli bacteria, enterohaemorrhagic E. coli (EHEC), which can cause haemorrhagic colitis with bloody diarrhoea. While most E. coli bacteria are harmless, the EHEC group can produce toxins, known as Shigatoxins or verotoxins, which damage blood cells and the kidneys. EHEC bacteria that produce these toxins belong to the so-called Shigatoxin-producing E. coli (STEC) or verocytotoxin-producing E.coli (VTEC).
As of 30 May 2011, 400 cases of HUS and 843 cases of EHEC infection (1243 in total) were reported to WHO. Most of these were in Germany, where there were 373 cases of HUS and 796 of EHEC.
To date, all cases but two were reported in people who had travelled to or been in northern Germany during the incubation period for the disease. One laboratory-confirmed case of EHEC infection and HUS with no apparent link to Germany or to other known cases was reported in Denmark, and in Norway there was a case where the patient had a visitor from Germany.
As of 30 May 2011 in Germany, 61% of reported EHEC cases were in women and girls, and 88% in people aged 20 years or older. The corresponding figures for HUS cases were both 88%.
Investigations under way
Epidemiological, microbiological, food-safety and trace-back investigations are continuing, to create a better understanding of the epidemiology of the outbreak and to try to identify the source, as no definitive source has yet been confirmed.
Remaining alert for symptoms
EHEC infections can cause bloody diarrhoea and abdominal pain. People who develop these symptoms and who are in or have recently visited Germany, particularly northern Germany, should seek medical advice urgently and tell their doctors about their travel to Germany.
The complication of HUS can cause acute kidney failure and can develop after the diarrhoea has resolved. Treatment with anti-diarrhoeal products or antibiotics is not usually recommended, as these may worsen the situation.
Recommendations and precautionary measures
Regular hand washing, particularly before food preparation or consumption and after toilet contact, is highly recommended, particularly for people who care for small children or are immunocompromised, as the bacterium can be passed from person to person, as well as through food, water and direct contact with animals.
WHO does not recommend any restrictions in travel to or trade with Germany.
HUS is a life-threatening disease that can lead to acute renal failure (uraemia), haemolytic anaemia, and a low platelet count (thrombocytopenia). It affects children predominantly but not exclusively. HUS results from EHEC infection, and it is estimated that up to 10% of EHEC-affected patients may develop HUS, with a mortality rate of up to 5%.
Overall, HUS is the most common cause of acute renal failure in young children. It can cause neurological complications (such as seizure, stroke and coma) in 25% of patients and chronic renal sequelae, usually mild, in around 50% of survivors.
EHEC is a severe strain of E. coli bacterium that is commonly found in the gut of animals, mainly ruminants. EHEC produces toxins, known as Shigatoxins or verotoxins, which damage blood cells and the kidneys. EHEC bacteria that produce these toxins are known as STEC or VTEC. The name Shigatoxins refers to their similarity to the toxins produced by Shigella dysenteriae. These toxins can cause severe foodborne diseases.
EHEC is transmitted to humans primarily through consumption of contaminated foods, such as raw or undercooked ground-meat products and raw milk, fresh produce, contaminated water, direct contact with animals or contact with infected people. It is destroyed by thorough cooking of foods until all parts reach a temperature of 70 oC or higher.
Symptoms of disease include abdominal cramps and diarrhoea, which may be bloody. Fever and vomiting may also occur. Most patients recover within 10 days, although in a few cases (particularly in young children and the elderly), the infection may lead to a life-threatening disease, such as HUS.
Preventive measures for EHEC infections are similar to those recommended for other foodborne diseases, including basic good food-hygiene practice.