[userulluipeste]

We are lucky that mass epidemics that plagued humans so far didn't affect the brain. Affections like rabies, that require individuals biting each other, and which are the inspirational source of all those zombie fantasies, do not count. That is an attack vector easy to spot and manage. The scary scenario is the one like with this Sporothrix Brasiliensis fungus, which can spread by merely "sneezing out the infectious yeast", and then remain potent (outside a host) for "up to 10 weeks", plus (the cherry on top) -- "developing the disease three years after" the infection event. Any kind of pandemic is scary by the sheer magnitude of its reach, but one that would affect the brain? That would be another level of scary.

[curiousthought]

Toxoplasma gondii affects animal behavior, I don't think it's a stretch to think it (or something similar) could affect humans in some way we haven't measured yet.

[fipar]

I think it’s very common for parasites to affect their host’s behavior.

If you find this topic interesting, I recommend the book “Parasite Rex”

[bee_rider]

I think this is widely speculated already, right? It is just hard to measure human behavior. I mean one of the proposed effects on Wikipedia is a reduced aversion to cat urine. But obviously there is a correlation/causation question there, haha,