herpes vs herpes virus

herpes

noun
  • A viral infection, caused by Human alphaherpesvirus 1 and Human alphaherpesvirus 2, marked by painful, watery blisters in the skin or mucous membranes or on the genitals. 

herpes virus

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