Public Health Wales have published more details of the number of cases of measles in an outbreak centred on Swansea.
The data shows that the number of cases has risen rapidly in February and March.
It also shows that children aged between 10 and 14 years old are the most at risk.
2013 is expected to be the worst year for measles in the UK for the past two decades. Read more about the illness and how it is treated.
If the Government's top adviser on immunisation thinks the risk of an emergency in England is a possibility, I believe him.