Mind Toxoplasma gondii

Published on September 24th, 2012 | by No Artificial

Common Parasite Can Change Your Personality

The infectious parasite carried by cats may cause personality changes and even mental illness.

About 40 percent of the world’s population is infected with Toxoplasma gondii, including about 22.5 percent Americans older than 12 years old.
Human contamination generally occurs when people eat raw or undercooked meat that has cysts containing the parasite, unwashed fruits or vegetables from contaminated soil, or when they come into contact with the T. gondii eggs while cleaning a cat’s litterbox, gardening, or playing in a sandbox, for instance. The parasite is known to be dangerous to pregnant women as it can cause disability, brain damage or abortion of the unborn child.
Of those who are infected, very few have physical symptoms. However, it now appears that even a hidden infection can result in mental and behavioral changes that can be just as devastating.

In a new study conducted by Jaroslav Flegr, the professor of parasitology at Charles University in Prague, Czech Republic, researchers analyzed participants for Toxoplasma gondii infection and had them complete a personality questionnaire. They found that both men and women infected with the parasite were more extroverted and less conscientious than the infection-free individuals. According to a study published in the May/June issue of the European Journal of Personality, these personality changes are thought to result from Toxoplasma gondii’s influence on brain chemicals.

“Toxoplasma manipulates the behavior of its animal host by increasing the concentration of dopamine and by changing levels of certain hormones,” explained study author.

The Czech scientists have begun to unpick Toxoplasma gondii’s effects on behaviour in the mid-1990s, discovering that infected people showed different personality traits to non-infected people – and that the differences depended on sex. Infected men were more likely to be aggressive, jealous and suspicious, while women became more outgoing and showed signs of higher intelligence.

Professor Flegr claims that his most important finding was in 2001 – and it showed, he says, that people who were infected by T.Gondii, but not showing symptoms, were 2.7 times more likely than uninfected people to be involved in a car accident as a driver or pedestrian.

If Flegr is right, this common parasite may change our response to frightening situations, our trust in others, how outgoing we are, and even our preference for certain scents. And that’s not all. He also believes that the organism contributes to mental disorders such as schizophrenia. When you add up all the different ways it can harm us, says Flegr, “Toxoplasma might even kill as many people as malaria, or at least a million people a year.”

Furthermore, the new research led by Michigan State University, which has been published in the August issue of The Journal of Clinical Psychiatry, revealed that if you are positive for the parasite, you are seven times more likely to attempt suicide.

While the scientists call for further studies focusing on the biological mechanisms of the parasite and how it may affect people’s behavior, people should cook their meat through and wash their fruits and vegetables to avoid spreading or contracting the parasite.

Scientific American

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