Now "measles is bad" is considered wrong. "Measles" is a disease-- singular. There is no such thing as a measle!
I thought "Measles is bad" was wrong, but apparently it is indeed singular.
I looked it up and measles is bad is also right in English, it should be accepted
I reported it 10/10/19
Measles is plural in form, but usually used with a singular verb.
Thus 'measles is bad' is to be preferred.