Mind-Altering Parasite May Make Infected People More Attractive, Study Suggests
(www.sciencealert.com)
Scientifically it's called mutualism, and it happens all the time in nature, including in humans. The bacteria in your gut require you to live, and for you to live requires having those bacteria in your gut. And the bacteria in your gut effect your mind, including the decisions you make
https://en.wikipedia.org/wiki/Mutualism_(biology)