Escherichia coli, or E. coli, is a common bacterium that lives in the intestines of most warm blooded animals, including humans. All of us have billions of E. coli bacteria in our guts. The overwhelming majority of strains are harmless or even beneficial to their hosts, as they generate vitamin K, an important micronutrient, and crowd out other, more dangerous bacteria. A few E. coli strains, however, are pathogens that can cause serious infections. Among the most potent of these is the O157:H7 strain, which is responsible for the outbreak traced to Godstone Farm.
O157:H7 infections cause diarrhoea, often with blood in the stools, and stomach cramps. These symptoms commonly last up to a week, and do not usually require treatment.Particulary severe infections, however, can cause haemolytic-uraemic syndrome, which leads to the destruction of red blood cells and kidney failure and can be fatal. Children under the age of 5 are particularly at risk, as are the elderly.
Both groups tend to have weak immune systems, and also have lower concentrations of beneficial microbes called bifidobacteria in their intestines, which can help to prevent and fight E. coliO175:H7 infections.Dehydration caused by severe diarrhoea is also more of a risk to health in the young and old. E. coli O157:H7 is usually transmitted as a food-borne illness, typically in beef. The strain is not harmful to cattle, and about 15 per cent of cattle are estimated to be infected with it.
The risk to humans comes if beef from infected cattle is contaminated with faeces or gut contents during slaughter or butchering. The bacteria can still be killed by full cooking, but undercooked beef can present an infection risk. The risk from mince is higher because it is more likely to be contaminated than prime cuts.
The bacteria can also be transmitted through contact with infected animals, as appears to have happened at Godstone Farm. This can happen when faeces containing E. coli O157:H7 get on to a person's hands, such as by petting an animal, and then into the mouth. O157:H7 infections are treated by anti-diarrhoeal medication and fluid replacement. Paracetamol (though not non-steroidal anti-inflammatories such as ibuprofen) can be used to control stomach pain. Antibiotics are not effective, and may worsen symptoms by killing beneficial gut bacteria that help to control the infection.
Source : What is E coli and why can it be deadly? - Times Online (http://www.timesonline.co.uk/tol/news/science/article6832844.ece)
For More Information:
Info : http://en.wikipedia.org/wiki/Escherichia_coli
Info : What is E.Coli O157:H7? (http://www.ericsecho.org/whatisec.htm)
Info : BBC News - Q&A: E. coli outbreak (http://www.bbc.co.uk/news/health-13600144)