Cat Parasites & Mental Illness

According to the U.S. Centers for Disease Control and Prevention, 60 million Americans are thought to be infected with toxoplasmosis, which is caused by a parasite found in, among other things, cats. Most of those who contract the parasite won't know anything about it, because the infection is usually harmless. But recent studies have shown it can lead to an increased risk of developing a mental illness.

  1. Causes of Toxoplasmosis

    • Toxoplasmosis is caused by the Toxoplama gondii parasite, which can be found in cat faeces, cat litter or soil that is contaminated with cat feces. It has also been found in undercooked or raw meat and raw cured meat, such as Parma ham, according to the UK's National Health Service (NHS).

      Toxoplasmosis cannot be passed through human-to-human contact, except between a pregnant woman to her unborn child. Children born with this condition have congenital toxoplasmosis, according to the NHS.

    Toxoplasmosis Symptoms

    • There are few symptoms when someone becomes infected with toxoplasmosis. In 80 percent of cases, the infection causes no symptoms because a healthy immune system is strong enough to keep the parasite from causing illness, so it lives harmlessly in the body for life, according to the NHS. In a few cases, the parasite causes flu-like symptoms, including muscle aches, a fever of 100.4 degrees F or higher, tiredness, nausea and a sore throat.

    Schizophrenia Link

    • A 2008 study carried out on U.S. military personnel by researchers from Walter Reed Army Institute of Research and Johns Hopkins Children Center found that out of 180 of those with schizophrenia, 7 percent had been infected by toxoplasma before their diagnosis. This was compared with 5 percent of 532 healthy recruits.

      While the difference is small, the researchers believed the ability to explain a small portion of the 2 million cases in the United States may offer clues to the disease and possible treatments. This could include treating schizophrenic with anti-parasitic drugs.

    Expert Insight

    • Robert Yolken, M.D., a neurovirologist at John Hopkins Children's Center who helped conduct the research says, "Our findings reveal the strongest association we've seen yet between infection with this very common parasite and the subsequent development of schizophrenia."

      Yolken adds that this is the first study to show a parasite infection can precede the onset of schizophrenia. Other studies have confirmed the link between schizophrenia and the presence of toxoplasma antibodies.

    Schizophrenia Symptoms

    • Those with schizophrenia experience a wide range of symptoms of mental illness, including hallucinations (seeing things that are not there) and delusions (believing things that are not true).

      Around one in 100 people experience an acute schizophrenic episode at least once in their lifetime. The condition usually starts between 15 to 30 years of age for men and 25 to 30 years of age for women. Misconceptions about the illness include the idea that sufferers are violent or have a dual personality.