Six cases of the infection have been reported since the beginning of July, with two new cases in Pembrokeshire in the last week.
The new cases – one probable and one confirmed – are in addition to four cases previously reported in Swansea, Neath Port Talbot and Powys.
All cases have links to festivals in England, leading Public Health Wales to urge people not to attend big events without checking they and their children are up to date with MMR vaccination.
Sion Lingard, Consultant in Health Protection for Public Health Wales, said: “After not seeing cases of measles in Wales for some time, we’re concerned at six cases being reported in just over a month. It is important that those that have not received two doses of the MMR vaccine get vaccinated so that they are protected from this preventable disease.
“People who are not vaccinated not only risk catching measles themselves, but could also pass it to babies too young to have received MMR and who are at risk of serious complications.
“Anyone who has a rash that could be measles is urged not to attend events where unvaccinated people could be present, but to seek advice from their GP. Do not attend A&E or your GP surgery without calling first as if you do have measles, you could pass it to others in the waiting room.”
Measles is a serious and highly contagious viral disease that can cause complications and can even prove fatal. The illness starts with cold or flu-like symptoms, followed by a rash after 2-4 days.
Crowds of people provide the perfect environment for infectious diseases like measles to circulate, but two doses of the safe and effective MMR vaccine offers protection.
Many people who catch measles will have a fever, cough, red eyes, and blocked nose and feel generally unwell. The blotchy rash appears a few days later beginning on the face and spreading downwards to the rest of the body over several days.
If you have not received two doses of MMR and attend large events where hundreds of people are present, you are at risk of contracting measles. People around you may not have any symptoms, but could still be infectious.
Vaccination is free on the NHS by arranging an appointment with your GP, and it’s never too late to catch up on missed doses.
Children should receive their first dose of the vaccine at 12 months of age and the second at around three years and four years of age, but older children and adults can receive the vaccination at any time.