In informatics?, ...
In biology, a host is an organism who harbors a parasite?, providing nourishment and shelter. A cell can be host to a virus, an animal can be host to a parasitic worm, e.g., a nematode?. A primary host or definitive host is a host in which the parasite grows mature; a secondary host or intermediate host is a host that harbors the parasite only for a short transition period. For trypanosome?s, the cause of [sleeping sickness]?, humans are the primary host, while the [tsetse fly]? is the secondary host.