crab louse vs herpes simplex

crab louse

noun
  • A parasitic insect, Pthirus pubis, that lives amongst the pubic hairs of humans and feeds on blood. 

herpes simplex

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

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