Around 60 million people in the US may be infected with T. gondii, which comes from eating undercooked, contaminated meat, drinking contaminated water, and coming into contact with cat feces. According to a new research study, the parasite responsible for toxoplasmosis – Toxoplasma gondii- may be attributed to around a fifth of schizophrenia cases in the US.
Most people are unaware they have the infection since those with healthy immune systems are able to stop the parasite causing illness. Previous studies have linked T. gondii infection to mental health conditions, such as increased chance of self-harm or suicide. More recently, studies have linked T. gondii to schizophrenia, so this study’s goal was to better understand the link between the two.
Researchers wanted to determine the number of schizophrenia cases attributable to T.gondii infection so they calculated the population attributable fraction. “In other words, we ask, if you could stop infections with this parasite, how many [schizophrenia] cases could you prevent?” explains Gary Smith, of the School of Veterinary Medicine at the University of Pennsylvania. After calculating the PAF fraction, Smith found that 21.4 percent, of around one fifth, of schizophrenia cases could be prevented by stopping T. gondii infections from occurring.
“By finding out how important a factor T. gondii infection is, this work might inform our attitude to researching the subject,” said Smith. “Instead of ridiculing the idea of a connection between T. gondii and schizophrenia because it seems so extraordinary, we can sit down and consider the evidence. Perhaps then we might be persuaded to look for more ways to reduce the number of people infected with toxoplasma.”