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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Rhondda Cynon Taf Council passed the motion of no confidence in Cwm Taf health board.
Increasing amounts of cloud will push in from the west this evening, along with some scattered showers.