[henry quirk]

"But there are cases where the parasite isn't just feeding off of, or damaging us, but actively controlling our behavior. Toxoplasmosis makes mice unafraid of cats, and seems to cause increased risk-taking in humans as well."

I reckon such invasions are the exception not the rule. And if not: I reckon we'll incorporate such bugs into ourselves, turn them useful, to our advantage (as multi-cellulars did with gut flora).

#

"In the days following an exposure to the flu virus--before symptoms take hold and when the host is the most contagious--humans have been shown to become significantly more social than they normally would be, presumably to unwittingly spread the virus."

I suspect such folks were sociable types to begin with. Misanthropes like me probably aren't moved much by vira or other micro-opportunists.

#

"So-called "lesser" creatures neurologically control us on a regular basis."

'Influence', sure; 'control' mebbe not so much.