More than 30 people have caught the E.coli vomiting bug in an outbreak in Surrey.
Normally, it only affects about 30 people in the country every year.
What is E.coli?
E.coli is a common bug which is found everywhere in the environment. Mostly, it helps people to stay healthy, providing the body with many vitamins.
But some strains - such as the 0157 strain, which caused problems in an outbreak in Wales in 2005 - can be deadly.
How can you get infected?
By handling raw meat, eating undercooked meat, drinking untreated milk or dairy products, direct contact with animals, or close contact with another infected person.
What are the symptoms?
The condition is described as a serious form of food poisoning and symptoms can range from mild diarrhoea to serious stomach cramps.
Most people shake off the bug in around a week with the help of antibiotics.
But in rare cases some patients suffer from a complication, which kills red blood cells and can cause kidney failure.
Children, because they are so small, and the elderly, because of their weakened immune system, are most at risk.
What can be done to stop infection?
A study held after a previous E.coli outbreak suggested that kids should get lessons in handling food.
It called for better training for people who work in slaughter houses, farms and butcher shops. It also said raw and cooked meats should be separated in kitchens.
Washing hands after handling food is also very important.