cockroach vs helminth

cockroach

noun
  • A black or brown straight-winged insect of the order Blattodea. 

  • A Tutsi. 

  • A person from New South Wales. 

  • A person or a member of a group of people regarded as undesirable and rapidly procreating. 

helminth

noun
  • A parasitic worm; a fluke, tapeworm, or nematode. 

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