malaria vs protozoal infection

malaria and protozoal infection both are nouns.

Word	Noun	Adjective	Verb	Adverb
malaria	Yes	No	No	No
protozoal infection	Yes	No	No	No

As nouns, protozoal infection is a hypernym of malaria; that is, protozoal infection is a word with a broader meaning than malaria:

malaria: an infective disease caused by sporozoan parasites that are transmitted through the bite of an infected Anopheles mosquito; marked by paroxysms of chills and fever
protozoal infection: any infection caused by a protozoan

malaria (noun)	protozoal infection (noun)
an infective disease caused by sporozoan parasites that are transmitted through the bite of an infected Anopheles mosquito; marked by paroxysms of chills and fever	any infection caused by a protozoan