Toxoplasma gondii is a bit overrated in my opinion. Unless your immune system is compromised or you're pregnant, there's no scientific proof that there's immediate danger from it. And if your immune system is weak or you're pregnant, you have a good excuse to make someone else clean the cat litter ;-)

Also my behavior is influenced by a lot of things outside my control: Genes, hormones, antidepressants[1]... what do I care if a parasite adds to the mix?

[1] While I can control my intake, I can't control the side-effects.

The claim is not that there is an immediate danger. The claim is that there is a subtle, bad influence.

The article itself seems to be talking more about the perceived sense of self is, and how that might be affected by organisms that replace our existing organisms.

The title led me to believe it might be something more like the gondii situation mention.

There is perhaps an association between gondii and schizophrenia. Here is one meta analysis[1]

"The results suggest that individuals with schizophrenia have an increased prevalence of antibodies to T. gondii. This association is consistent with other epidemiological studies as well as with animal studies."

[1] http://schizophreniabulletin.oxfordjournals.org/content/33/3...