If you are interested in this subject, Carl Zimmer wrote a great book that has all sorts of examples of parasites that control their host: "Parasite Rex: Inside the Bizarre World of Nature's Most Dangerous Creatures"

https://www.amazon.com/Parasite-Rex-Bizarre-Dangerous-Creatu...

The inverse correlation between parasitic infections and autoimmune disease is interesting and is explored in Parasitic worms and inflammatory diseases, P. Zaccone et. al. [1].

In parts of the world, for example USA, Canada, Australia, Europe, other locations, serious parasitic infection are now not common. The immune system, which co-evolved with parasites over millions of years appears to turn on our own bodies because of the lack of parasites to attack. This hypothesis (the hygiene hypothesis) is investigated in the cited paper.

I referred to serious parasitic infections above because virtually everyone host some benign parasites such as the Demodex mite, a microscopic mite that lives on our eye lashes. See [2].

Finally, let me recommend Parasite Rex... by Carl Zimmer. [3]

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1618732/

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3884930/

[3] https://www.amazon.com/Parasite-Rex-Bizarre-Dangerous-Creatu...

I'd also recommend Upstream Color, which has an almost more creatively baroque yet strangely logical plot.

Maybe mix it with this:

http://www.amazon.com/Parasite-Rex-Bizarre-Dangerous-Creatur...

We are safe not just thanks to reason in our social behaviour, but also our hygiene:

http://www.amazon.com/Parasite-Rex-Bizarre-Dangerous-Creatur...

I thought that anyone who has raised a cat knows that animals are jerks (playing with bleeding mice for hours and all), but I was shocked by the added layer of terribleness from parasites in almost all species.