acquired immune deficiency syndrome vs crab louse

acquired immune deficiency syndrome

noun
  • An infectious disease, caused by HIV, that causes the gradual degeneration of the body's immune system. 

crab louse

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

How often have the words acquired immune deficiency syndrome and crab louse occurred in a corpus of books? (source: Google Ngram Viewer )