bejel vs chancroid

bejel

noun
  • Endemic syphilis, a chronic disease of skin and tissue caused by infection by a subspecies of the spirochete Treponema pallidum. 

chancroid

noun
  • A sore characteristic of this infection. 

  • A sexually transmitted infection, caused by bacteria of species Haemophilus ducreyi, characterized by painful sores on the genitalia. 

How often have the words bejel and chancroid occurred in a corpus of books? (source: Google Ngram Viewer )