"Ring Around the Rosey" comes instantly to mind.
"Since the 20th century, the rhyme has often been associated with the Great Plague which happened in England in 1665, or with earlier outbreaks of the Black Death in England. Interpreters of the rhyme before the Second World War make no mention of this; by 1951, however, it seems to have become well established as an explanation for the form of the rhyme that had become standard in the United Kingdom. Peter and Iona Opie, the leading authorities on nursery rhymes, remarked:
The invariable sneezing and falling down in modern English versions have given would-be origin finders the opportunity to say that the rhyme dates back to the Great Plague. A rosy rash, they allege, was a symptom of the plague, and posies of herbs were carried as protection and to ward off the smell of the disease. Sneezing or coughing was a final fatal symptom, and "all fall down" was exactly what happened.
The line Ashes, Ashes in colonial versions of the rhyme is claimed to refer variously to cremation of the bodies, the burning of victims' houses, or blackening of their skin, and the theory has been adapted to be applied to other versions of the rhyme. In its various forms, the interpretation has entered into popular culture and has been used elsewhere to make oblique reference to the plague."