April 04, 2007

Toxoplasma Gondii ("Cat Parasite") Schizophrenia Link Studied

Exposure of pregnant women to several infectious agents -- including influenza, sexually transmitted diseases, and Rubella -- have been associated with the later development of schizophrenia. Several studies have been reported in the past month investigating the link between one such infectious agent in a pregnant mother - a common protozoan infection of Toxoplasma gondii - and the baby's later development of schizophrenia.

Toxoplasma gondii is commonly known as a 1-celled parasite carried by cats. But people can acquire it from eating undercooked meat as well as from contact with gardening soil and litterboxes used by cats. Infection by this virus is called "toxoplasmosis". Once it is inside of us either by ingestion (swallowing it) or by inhalation (breathing it in), it lives inside our infected cells.

PsychiatryMatters.MD reports about one study in Denmark which showed that newborn babies with high levels of an antibody, called immunoglobulin G (IgG), specific to T. gondii, had an increased risk (1.79 times greater) of developing schizophrenia. These high levels of the antibodies were not seen in the babies that later developed other schizophrenia-like disorders or affective disorders.

The investigators of this study do not know at what stage of pregnancy the mother had contracted the infection, although lack of a different antibody, IgM, indicates that an infection during the first trimester of pregnancy was not the cause.

The authors discuss that either the mother's own antibodies to the parasitic infection may be the cause of the baby's later development of schizophrenia by affecting the fetus' developing central nervous system, or, the cause might be the effect of the infection itself in the developing baby.

They write:

"T. gondii is a plausible candidate to cause a persistent neuropsychiatric disease such as schizophrenia for a variety of reasons. It is neurotropic, affects both neurons and glia, is known to directly affect neurotransmitters, affects cognitive function, and is inhibited in cell culture by some antipsychotics and mood stabilizers."

Read the full article: Maternal T. gondii infection 'risk factor for early-onset schizophrenia'
Source Abstract: Early Infections of Toxoplasma gondii and the Later Development of Schizophrenia (Biol Psychiatry 2007; 61: 688-693)

Other recent study abstracts:

Related Reading:
Infections as a causal factor in schizophrenia

Scientists: stronger link between cat virus and schizophrenia

Cat Parasite Linked to Schizophrenia

Pregnancy, Cats and Schizophrenia


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