chancroid vs genital herpes

chancroid

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

  • A sore characteristic of this infection. 

genital herpes

noun
  • A genital infection caused by herpes simplex viruses (mostly HHV2 but also HHV1). 

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