 They were surprised to find that it looked like a giant iridovirus, which are icosahedral viruses that infect insects, fish, and frogs.Knowing this paved the way for the discovery of mamavirus because scientists knew to look for other giant viruses.It was originally isolated from "Acanthamoeba polyphaga", but subsequent work has involved "Acanthamoeba castellanii" ("Acanthamoeba castellanii mamavirus", ACMV).