Research shows spending your childhood with the feline companions may be a risk factor for developing schizophrenia and other mental illnesses. The culprit is a single-celled parasitic organism called Toxoplasma gondii.

Toxoplasmosis is the disease caused by T. gondii or commonly known as Toxo. The organism is present in various birds and mammals, but it has a unique relationship with cats. It is found in feces of cats and it also helps them prey on rodents (rodents infected with Toxo lose their fear of cats).

According to Center for Disease Control, although the parasite is found all over the world, as many as 60 million people in the United States are thought to be infected with T. gondii.

Accidental ingestion of cat’s fecal matter can infect humans. This can occur while gardening or changing the cat’s litter boxes. Not washing hands properly after these activities or eating unwashed fruits and vegetables can also lead to risk of infection. Other than cats, eating raw or uncooked meat, poultry and seafood can also pose a threat.

Normally a healthy person’s immune system can prevent the parasite from causing any disease but it can pose serious health risks such as birth defects and miscarriages to pregnant women and people with compromised immune systems. Studies have also reported a link between Toxo and mental disorders.

In this study published in the June edition of Schizophrenia Research, a comparison of two studies was conducted in which a link was discovered between developing schizophrenia in later life and owning cats. The results indicate that owning a cat could lead to a greater risk of developing mental illness.

Authors E Fuller Torrey, Wendy Simmons and Robert H Yolken said, “Cat ownership in childhood had been reported in three studies to be more common in families where the child was later diagnosed with serious mental illness such as schizophrenia.”

In another study, published in Acta Psychiatrica Scandinavica journal, AL Sutterland and his fellow researchers from Academic Medical Center in Amsterdam, reviewed some 50 studies to establish a link between Toxo and mental disorders. Their results showed that people infected with T. gondii were twice as likely to develop schizophrenia.

Cats can excrete many millions of T. gondii eggs, which have the ability to lay dormant in water and soil for many years afterwards. Outdoor cats and feral cats pose a greater risk of infection than household cats. But this doesn’t mean that cats have to be abandoned as pets. Some simple precautions can be taken to prevent infection and still keep those lovable felines around the house. These precautions are:

  • Wash all unpeeled fruits and vegetables thoroughly.
  • Do not drink unpasteurized milk, especially goat milk.
  • Freezing meat below zero for several days can help reduce infection chance.
  • Properly cook meat and poultry at safe temperatures.
  • Clean utensils, dishes, knives, chopping boards and hands with hot soapy water after contact with raw meat, poultry, seafood, fruits or vegetables.
  • Wash hands thoroughly after gardening or cleaning litter boxes. Using gloves during these activities is preferable.
  • Keep sandboxes covered when not in use.
  • Do not let children come near litter boxes.
  • Do not feed the cat raw or uncooked meat. Litter boxes should be cleaned daily. Keep the pet away from stray cats.
  • Pregnant women should not handle or clean litter boxes. If they must, use gloves and wash hands thoroughly afterwards.