Tens of thousands of children are potentially at risk if the measles outbreak spreads beyond South West Wales, according to a public health expert.
Dr Meirion Evans from Cardiff University says he expects hundreds more cases to be confirmed in coming days and weeks.
Fresh measles cases have been reported in Powys and Cardiff. A public health expert warned tens of thousands of children could be at risk.
Public Health Wales has information and advice on measles - a highly-infectious viral illness which can have life-threatening complications.