chlamydia vs herpes simplex

chlamydia

noun
  • Any of several common, often asymptomatic, sexually transmitted diseases caused by the microorganism Chlamydia trachomatis. 

  • Any of various coccoid microorganisms of the genus Chlamydia that are pathogenic to humans and other animals. 

herpes simplex

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

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