Infection of Toxoplasma gondii linked to Neurological Disorders

Toxoplasma gondii is found in almost every country in the world.   It is most common in species of carnivores, insectivores, rodents, and other animals.  It is widespread throughout the human population and infection of this parasite can lead to neurological issues.  Toxoplasma gondii is an intracellular parasite of muscle and intestinal tissues (Pedersen 2012).  The two main stages in Toxoplasma gondii are sexual reproduction, which occurs only in cats and felines, and asexual reproduction which occurs in intermediate hosts.  This means that a cat is the only definitive host for this parasite.  Only inside a cat can the parasite produce oocysts or infective eggs.  A cat becomes infected with this parasite by ingesting a Toxoplamsa gondii infected rat. The parasite travels from the ingested animal into the intestinal ducts of the cat.  The parasite then attaches to the lining of the intestinal wall and produces oocysts which will eventually infect the muscles and brain of its next victim.  The oocysts are transferred into intermediate hosts when feces from an infected cat are ingested (Pedersen 2012).  When a second intermediate host becomes infected with the Toxoplasma gondii parasite, specifically a rat, the parasite alters the rat’s neurochemical pathways in the brain to disable its innate behavior to fear their predator, the cat. This makes it easy for the parasite to get into the cat since the rat will be an easy target for prey. 

             Toxoplasma gondii is extremely dangerous to all intermediate hosts including humans.  Researchers have found links between T.gondii infection and physiological disorders.  In a study done by E. Fuller Torrey in 2003, a correlation was found between T.gondii infection and schizophrenia (Pedersen 2012).  It was discovered that Toxoplasma infected pregnant women were more likely to give birth to schizophrenic children (Pedersen 2012).  T.gondii infection was also linked to neuroticism in both men and women.  The reasoning behind these psychological abnormalities is that immune response created in reaction to this parasite produces high levels of cytokines.  High levels of cytokines are associated with depression and the tendency to experience negative emotional states (Pedersen 2012).  These cytokines pass through the blood-brain barrier and alter the chemical neurotransmitter pathways, disrupting our way of thinking.   Toxoplasma gondii is a parasite that can manipulate behavior and ultimately cause insanity. 

Bibliography

Pedersen, Marianne G. "Toxoplasma Gondii Infection and Self-directed Violence in MothersToxoplasma Gondii and Self-directed Violence." Arch Gen Psychiatry (2012): n. pag. PubMed.gov.