Any organism that can only replicate within a host.
a parasite that is incapable of existing independently of living tissues.
a parasite that, in nature, can grow and multiple only on or in living organisms
Organism that can survive only on or in living tissues.
An organism that is incapable of living as a saprophyte and must live as a parasite. ( 15)
An obligate parasite is an organism that cannot live independently of its host. For example, a virus is an obligate parasite because it cannot reproduce outside a host cell.