All your brain cells are belong to us. 
The hypothesis presented in the Atlantic article is that the parasite changes rat behavior: consequences for humans are side effects.
The article points out that the effects are modest over the population, though they may affect certain individuals in a more pronounced way.
There may be unknown parasites whose primary goal is to affect human behavior.
The parasite is very subtle, causing us to use effect (meaning “cause to happen” when used as a verb) when we mean affect (meaning “influence or change.”)
I just finished reading the linked article, and all I have to say is that this is a real catastrophe.
You can’t have both the parasites, why don’t you take the blood parasites.
I think you have a really poor understanding of what goes on in the UK. There is lots of random violence, street crime and anonymous sex. Much of this can be attributed to its irresponsible drinking culture.
:smack: Great, something else to worry about.
Consider it a type of aversion therapy - if eventually you have too much to worry about, you won’t be able to worry about anything. 
It seems unlikely that this particular parasite would cause people to like cats more, though it’s an interesting idea. It causes mice to be attracted to cats because it needs the mouse to be eaten by a cat to continue it’s life cycle. The chemicals it uses to influence mice brains don’t necessarily cause the same behavioral effects in humans, though they may cause some other unknown changes.
It’s not just Toxoplasma gondii that is possibly affecting human behavior either. We have a lot of different micro-organisms living inside us, and molecules they release into the blood stream may find their way to the brain. There was a recent study that found implanting gut flora from an obese mouse to a normal mouse caused the fit mouse to become obese and develop metabolic disorders. So it’s possible the bacteria from an obese mouse were influencing the mouse to overeat for their own benefit.
If microbes have been influencing me for all my life, couldn’t those things also be said to be part of my person? Is there really a clear line on what is part of your “real” personality and what is not? If messenger molecules from bacteria I’ve had for a long time influence my decisions, is that really so different just because the source has different DNA than the rest of my cells? If I change suddenly because of a brain parasite, I could say that’s not a part of the real me, but personality and personhood aren’t very clear concepts in the first place.
A parasite that causes random anonymous sex?
Here, kitty kitty…
(and yes, I’ve watched Trainspotting).