A few scientific studies in the past years have discovered a parasite in cats called the "Toxoplasma" parasite. The mind-altering tricks of the Toxoplasma parasite, behind the disease, reverse the mouses instinctive fear of cat urine - instead making them attracted to pheromones it contains. Toxoplasma is known to influence the personality and behavior of infected men and women too. Research also suggests a mind-altering effect in people – one study found that sufferers have an increased tendency to be involved in car accidents due to slow reaction times, another has linked schizophrenia to the disease.
Upto 15-20% of people in the US are infected with this toxoplasma parasite, almost every one of those people do not know they're infected. It can slow a humans reaction time down by 15-30%. So if you're min-maxing in WoW and are finding your reaction skills just aren't as quick as other people, you may just be infected with the toxoplasma parasite.