Mae Prif Swyddog Meddygol Cymru, Dr Frank Atherton, wedi rhybuddio am y bygythiadau iechyd sy'n wynebu Cymru o ganlyniad i gynnydd mewn ymgyrchoedd gwrth-frechu a'r gorddefnydd o wrthfiotigau.
The Chief Medical Officer for Wales Dr Frank Atherton has warned of the health threats facing Wales from the rise in anti-vaccination campaigns and antibiotic overuse.