herpes vs venereal disease

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. 

venereal disease

noun
  • Any of several contagious diseases, such as syphilis and gonorrhea, contracted through sexual intercourse. 

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