Toxoplasma gondii is a parasite that can cause serious damage to people with weakened immune systems and pregnant women. Since its definitive host is the common house cat, there is great involvement of this animal in its transmission. A recent study however explores the implications of Toxoplasma in schizophrenia development in humans, a theory that scientists have been tacking for years.

Exposure to Toxoplasma is commonly addressed in regards to women who become pregnant, because they need to be tested for the presence of this parasite in their bodies. If a woman has encountered the parasite prior to becoming pregnant, then her baby and her are not in danger.

However, in the event that she becomes contaminated with the parasite during the pregnancy, there are serious risks to the outcome of the fetus. In about 55% of cases the disease is asymptomatic, and the fetus is safe. But out of the remaining 45% who do present symptoms, 30% of fetuses are born with severe abnormalities such as hydrocephalus and 9% of them die.

Aside from pregnant women, the parasite is also very dangerous for people who have weakened immune systems, such as those who are battling other major diseases at the moment of infection or those who are undergoing chemotherapy or suffer from AIDS. They are basically incapable of fighting the parasite and it goes rampant all throughout the body.

In these patients, it may cause severe neurological disorders like chronic encephalitis, if the parasite travels to the brain or extremely extensive damage to the eye, that can lead to blindness, if the parasite develops there.

The are two ways for humans to get contaminated with Toxoplasma gondii. The first involves a cat, most likely a pet,that is contaminated with the parasite and that sheds eggs along with the feces. Then, humans get contaminated by ingesting the eggs, by putting their unwashed hands in their mouth after cleaning the kitty litter.

There is also the possibility that the eggs are transported by an insect, such as a fly, from the kitty litter box on food or kitchenware. Another common contamination route is that involving public sandboxes that are uncovered and therefore may be contaminated with stray cat feces.

Despite the myth that Toxoplasmosis can only be transmitted by cats, the most common way people become contaminated requires no direct contact between humans and cats. The parasite can be transmitted through contaminated meet that is insufficiently cooked. The meat itself becomes contaminated when the animal it came from ingests the parasite eggs or more likely, contaminated meet itself.

It is only when the cat ingests the uncooked contaminated meet that it becomes infected with the parasite. This is why the Center for Disease Control and Prevention (CDC) advises that people do not feed raw meet to their cats and that pet cats are kept indoors, especially when the owners are pregnant women.

Furthermore, litter boxes should be covered when they are not being used, and the kitty litter should be changed daily. Pregnant women are advised to avoid cleaning litter boxes themselves, in possible.

Lately, there has been extensive research concerning the link between Toxoplasma and mental disorders in humans, particularly schizophrenia and bipolar disorder. This has been triggered by the discovery that that the parasite has the capacity of affecting the behavior of contaminated individuals.

The latest study was conducted by the Stanley Medical Research Institute and the team of scientists aimed to look deeper into the link of schizophrenia and Toxoplasmosis. And so, they studied over 2000 National Alliance for the Mentally Ill surveys that date back from 1982 and found that more than 50% of the families of patients with mental disorders had owned cats when the patients were in their childhood.

They cross-referenced these findings with two other studies and they noticed similar results. This study however does not directly link the parasite to the mental illnesses. It has used the ownership of cats as a possible relation tot the parasite, since they were unable to test the people who took the surveys for Toxoplasmosis.

There are other studies though that have identified a very close relationship between Toxoplasma and several mental disorders. For the moment, the patho-physiological path of this connection has not yet been established, but it does constitute the basis of future research that scientists plan to conduct.

Image Source: washingtonpost.com