herpes simplex vs sexually transmitted disease

herpes simplex

noun
  • A viral disease caused by Human herpesvirus 1 or Human herpesvirus 2 in genus Simplexvirus. 

sexually transmitted disease

noun
  • Any of various diseases that are usually contracted through sexual contact. 

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