pertussis vs infectious disease

pertussis and infectious disease both are nouns.

Word	Noun	Adjective	Verb	Adverb
pertussis	Yes	No	No	No
infectious disease	Yes	No	No	No

As nouns, infectious disease is a hypernym of pertussis; that is, infectious disease is a word with a broader meaning than pertussis:

pertussis: a disease of the respiratory mucous membrane
infectious disease: a disease transmitted only by a specific kind of contact

Other hypernyms of pertussis include respiratory disease, respiratory disorder, respiratory illness.

pertussis (noun)	infectious disease (noun)
a disease of the respiratory mucous membrane	a disease transmitted only by a specific kind of contact