Do not miss reading this full story. It is fascinating — featuring rats with  “fatal feline attraction,” differences among countries in neuroticism which coincide with higher rates of toxoplasma infection in its pregnant women and much, much more.

The Economist

“IF AN alien bug invaded the brains of half the population, hijacked their neurochemistry, altered the way they acted and drove some of them crazy, then you might expect a few excitable headlines to appear in the press. Yet something disturbingly like this may actually be happening without the world noticing.

“Toxoplasma gondii is not an alien; it is a relative of that down-to-earth pathogen Plasmodium, the beast that causes malaria. It is common: in some parts of the world as much as 60% of the population is infected with it. And it can harm fetuses and people with AIDS, because in each case their immune systems cannot cope with it. For other people, though, the symptoms are usually no worse than a mild dose of flu. Not much for them to worry about, then. Except that there is a growing body of evidence that some of those people have their behaviour permanently changed.”

Source: The Economist, June 3, 2010