Toxoplasma gondii is a tiny organism that lives inside cells. It might well live inside your cells — the parasite is thought to infect up to 50 percent of the world’s population, along with cats and many other animal species.
This is worrying, because many researchers believe that T. gondii infection, or toxoplasmosis, can alter human behavior. Among other organs, the parasite infects the brain, and it has been blamed for making people more impulsive, and more prone to mental illness, including schizophrenia. The idea of ‘behavioral’ toxoplasmosis has driven a huge amount of research and media interest. But in a new PLoS ONE paper, Duke University researchers Karen Sugden et al. suggest that there may be nothing to worry about after all. They report that toxoplasmosis is associated with essentially no behavioral abnormalities in humans.
Sugden et al. examined the Dunedin Longitudinal Study, a sample of over 1,000 people born in New Zealand in 1972-73 and followed up from birth. Sugden et al. tested the participants blood samples, taken at age of 38, for antibodies against T. gondii. Of 837 people who gave blood samples, 28% tested positive, indicating that they were infected with the parasite.
