Dr Marion Lyons of Public Health Wales says with 20 new cases of measles daily in Wales at the moment a death would not be surprising.
An investigation is underway on Friday to find out if a 25 year-old man from Port Tennant near Swansea died from the virus.
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Wales have qualified for the Euro 2016 quarter finals after beating Northern Ireland 1-0 in Paris.
A rally has been held in Cardiff following the EU referendum to show support to migrant communities.
It's 0-0 at half time in Paris as Wales face Northern Ireland in the last 16 of Euro 2016.