chancroid vs herpes

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. 

herpes

noun
  • A viral infection, caused by Human alphaherpesvirus 1 and Human alphaherpesvirus 2, marked by painful, watery blisters in the skin or mucous membranes or on the genitals. 

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