Larry Niven's "Smut Talk": Sentient bacteria of alien origin!

This is not among Niven's better stories.

Full story text can be downloaded here.

Story summary.
Draco Tavern, located somewhere in Siberia, is a kind of meeting place of sentient alien visitors to earth; entry of humans is heavily restricted by earth governments.

One fine day, you have the staff falling sick, & many aliens visitors suddenly going away. This happened a couple of days after an alien ship came.

Turns out human authorities have learned of a new species of sentient alien visitors unregistered till now. They are parasitic, in the form of fast multiplying bacterial colonies, & take control of the minds of hosts.

They were brought to earth via an alien male host bribed by bacteria of giving sexual pleasure through his long trip - presumably by directly simulating affected mind!

They have began spreading on earth at a speed that makes their hosts very sick.

Finally a treaty is worked out that they don't take over a host without his permission, & to restrict their colony size to something that doesn't threaten the host's life - in spite of the option to kill off the colonizers with antibiotics. In return, they will fix many life processes within host - basically improving the host! This was the part I found most difficult to believe - negotiations with parasites whose benefits are doubtful.

Final act is a female human volunteer asking to be infected. Via a human male host. And this infecting will happen through sexual intercourse between the two.

Fact sheet.
Smut Talk, short story, review
First published: Playboy (US), January 2000
Rating: C