A commenter suggested, not unreasonably, that the oft-repeated tale that Americans during the Great War not only took to calling sauerkraut “liberty cabbage,” but that they also renamed German measles “liberty measles,” sounds like a parody.
But from a website of the Schuylkill Haven, PA historical society, a news clipping from a local newspaper:
LIBERTY MEASLES BROKE OUT HERE
Schuylkill Haven was captured by the German measles this week and as a result some sixty to seventy five school children are prevented from attending school. … A month or so ago it will be remembered that a similar rash or disease was reported at several of the U. S. Army cantonments. The physicians diagnosed the disease as German measles but the soldiers would have nothing that had a German name to it so they styled the disease “Liberty” measles and that is what the disease is to be called in Schuylkill Haven henceforth.
Liberty measles are much less contagious than measles or scarlet fever. …
Schuylkill Haven was founded in the 18th Century by a German and all five individuals mentioned by name in the news story have German surnames, so I wouldn’t rule out that the reporter was having some subversive deadpan fun at the expense of the anti-German mania sweeping the country.
But this was a serious article about a local public health problem affecting children.