"Hostess" is a science fiction short story by American writer Isaac Asimov. It was first published in the May 1951 issue of Galaxy and reprinted in the 1969 collection Nightfall and Other Stories.
Humanity has spread out into the galaxy and made contact with four other intelligent non-human races. Harg Tholan, a medical doctor and researcher from the planet known as Hawkin's Planet arrives on Earth and visits Rose Smollett, a research biologist, and her husband Drake, ostensibly a police officer but in fact an agent of a secret government organization.
Dr. Tholan is researching a disease known as Inhibition Death, unknown on Earth. He describes his theory that a sixth, parasitic non-physical intelligence exists that lives in the minds of the humans and consequently is the reason that humans die of old age, whereas the four other life forms live indefinitely.
Drake, whose bureau already knows about this disease and the plans of the Hawkinsites, kills Tholan and disappears with the body, which is notable because the sixth intelligence is known to compel human beings to make themselves disappear.