gonorrhea vs syphilis

gonorrhea

noun
  • A sexually transmitted infection caused by Neisseria gonorrhoeae, a species of bacteria (the gonococcus) that affects the mucous membrane of the genital and urinary tracts. 

syphilis

noun
  • A disease spread via sexual activity, caused by the bacterium Treponema pallidum. 

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