herpes simplex vs tabes dorsalis

herpes simplex

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

tabes dorsalis

noun
  • tabes of the back; a degeneration of the sensory neurons of the spinal cord carrying afferent information. 

  • neurosyphilis in the form of such degeneration. 

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