title: Decreased level of novelty seeking in blood donors infected with Toxoplasma.
abstract: OBJECTIVE
  Toxoplasma gondii, a parasitic protozoan, infects about 30 - 60% of people worldwide. Toxoplasma is known to induce behavioral changes and an increase of dopamine in mice. The presence of anti-Toxoplasma antibodies (latent toxoplasmosis) is also a risk factor for schizophrenia. Latent toxoplasmosis in men (male soldiers) is associated with lower novelty seeking. As the novelty seeking is supposed to negatively correlate with level of dopamine, the observed effect was interpreted as indirect evidence of increased dopamine levels in subjects with toxoplasmosis. However, it is also possible that the observed effect was caused by association of both novelty seeking and Toxoplasma infection with a third factor, e.g. size of place of residence.
  
  
  METHODS
  Personality profile of 290 blood donors (205 men and 85 women) were measured by Cloninger's TCI (Temperament and Character Inventory) and their blood samples were assayed for the presence of anti-Toxoplasma antibodies. Difference between Toxoplasma-infected and Toxoplasma-free subjects was tested with ANCOVA method with gender, size of place of residence, and age as covariates.
  
  
  RESULTS
  The present analysis revealed that lower novelty seeking was associated with latent toxoplasmosis both in men and women. The effect of infection on novelty seeking remained significant even after adjustment for size of place of residence (p<0.01).
  
  
  CONCLUSIONS
  Decreased novelty seeking in Toxoplasma-infected subjects have been already confirmed in three independent populations (male soldiers and male and female blood donors). These findings suggest that the local inflammation-induced increase in dopamine in the brain of infected subjects can represent a missing link between toxoplasmosis and schizophrenia.
authors.affiliation: Department of Parasitology, Charles University, Vinicná 7, Prague 128 44, Czech Republic.
authors.forename: Anna
authors.initials: A
authors.lastname: Skallová
authors.forename: Martina
authors.initials: M
authors.lastname: Novotná
authors.forename: Petra
authors.initials: P
authors.lastname: Kolbeková
authors.forename: Zdenka
authors.initials: Z
authors.lastname: Gasová
authors.forename: Vladimír
authors.initials: V
authors.lastname: Veselý
authors.forename: Miluska
authors.initials: M
authors.lastname: Sechovská
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Flegr
mesh_terms: D000328:Adult; D000913:Antibodies, Protozoan / Q000032:analysis; D001782:Blood Donors / Q000523:psychology*; D004797:Enzyme-Linked Immunosorbent Assay; D005106:Exploratory Behavior / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010556:Personality Tests; D012201:Reward; D014123:Toxoplasmosis / Q000276:immunology / Q000523:psychology*
chemical_list: D000913:Antibodies, Protozoan