Causative agent
Escherichia coli (E. coli) is a bacterium that is commonly found in the gut of humans and warm-blooded animals. Most strains of E. coli are harmless. Some strains, however, such as Shiga toxin-producing E. coli (STEC), can produce powerful toxins and cause severe foodborne disease. The most recognised serogroup of STEC is E.coli O157:H7. Other uncommon strains e.g. E. coli O104:H4 may also cause serious disease as evidenced by the large-scale outbreak in Germany in 2011.
Clinical features
The STEC infection usually present with diarrhoea, often bloody diarrhoea, abdominal cramps and vomiting. In serious cases, the infection may lead to a life-threatening complication named haemolytic uraemic syndrome (HUS) which is a type of kidney failure. People of any age can become infected. Very young children and the elderly are more likely to develop severe illness, but even healthy older children and young adults can become seriously ill.
Mode of transmission
STEC is transmitted to humans primarily through consumption of contaminated foods, such as raw or undercooked ground meat products, contaminated fruits and vegetables, unpasteurised dairy products, contaminated water, and direct contact with animals or their environment. Direct person-to-person transmission through the oral-faecal route can also occur.
Incubation period
Can range from about 2-10 days, usually 3-4 days.
Management
Clinical management for STEC infection is usually supportive. Fluid and electrolyte replacement is important when there is severe diarrhoea. Patients with kidney failure may require specific supportive treatment and transfusion.
Prevention
Preventive measures for STEC infection are similar to those recommended for other foodborne diseases. Public are urged to observe good personal and food hygiene:
- Wash hands properly with liquid soap and water before eating or handling food, and after toilet or changing diapers.
- Cook food and boil water thoroughly before consumption. Most foodborne viruses and bacteria (including STEC) can be killed when food is cooked or reheated long enough at sufficient high temperature. When cooking or reheating, the core temperature of the food should reach at least 75℃.
- Young children, elderly people, pregnant women and persons with weakened immune systems should avoid eating high-risk food, e.g. unpasteurised milk, soft cheese, prepared or stored salads, and cold meats.
- Consult your doctor immediately if you have symptoms of STEC infection, particularly bloody diarrhoea.
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