Here’s an article from the June 4 1932 edition of the Toronto Daily Star describing the latest case counts for common diseases.
May 1932 appears to have been a bad month for mumps!
The reduced incidence of diphtheria might have been related to another article that appeared in the same paper:
Diphtheria vaccine was invented in 1923. Today, about 84% of the world is vaccinated, which is grimly ironic, given the current world situation.