The question is very simple, really: Could Toxoplasma gondii help your country win the World Cup?

Before we dismiss this idea, look at the observations/data here (and elsewhere...some I have linked here).

Toxo can be found in almost every type of mammal, from rats to humans. The overall goal of the parasite is to end up in a feline stomach, which is the only place it can reproduce. In other mammals, humans for example, the parasite heads for the brain. It is estimated that nearly 1/3 of the human population has a latent Toxo infection, with individual countries having infection rates varying from 6% (Korea) to 92% (Ghana).

Studies have also shown behavioral changes in humans, including slower reaction times and a sixfold increased risk of traffic accidents among infected males.

OK, back to soccer:

Countries with greater incidence of this parasitic infection in their populations tend to win more world cups than those without. The article, written by a Stanford University neuroscientist, goes on to try out various rationales for such a correlation, ranging from increased testosterone to increased dissent of authority — all symptoms of a Toxo infection.

Now we just need to find a parasite that causes an inability to referee properly, and we'll have this whole World Cup business all sorted out."