Unvaccinated children going on holiday to Europe could be at risk of catching measles, experts have warned.
A new case of the contagious illness has been diagnosed during an outbreak in Newport and Torfaen, bringing the total number to 13.
The measles outbreak is being linked to one in Europe that has infected 14,000 people since the beginning of the year.
Public Health Wales (PHW) urged parents to ensure their children have both MMR jabs.
"The outbreak in Europe poses a real threat to children in Wales who are not vaccinated, both those travelling to the continent over the summer holidays and those who come into contact with visitors from other countries who have measles," said Dr Rhianwen Stiff, consultant in communicable disease control for PHW.
"In this outbreak, we've seen measles passed between strangers who spent very little time in the same place, which underlines how very contagious this infection can be."
Children with measles symptoms - which include a high temperature, cough, runny nose, red eyes (conjunctivitis), and a distinctive red rash - are advised to be kept at home.
PHW is also urging parents not to take children with symptoms to the GP surgery, A&E department or hospital, where they could put other people at risk, without calling ahead first.
A rolling programme of vaccination sessions has already been completed in schools across Newport in response to the outbreak, with 1,089 children receiving immunisation.
Adults born since 1970, who have never had measles or the MMR vaccine, are also urged to ensure they contact their surgery about vaccination, especially if they work with children.