Relationship between Toxocara canis infection and schizophrenia

Objective To investigate the seropositivity rate for anti-Toxocara IgG antibodies in patients with schizophrenia and to assess its association with schizophrenia along with some risk factors for toxocariasis, eosinophilia and the presence of other intestinal parasites. Methods Serological examination of 90 schizophrenic patients and 45 healthy controls was carried out by using commercial Toxocara canis IgG ELISA kit for the detection of anti-Toxocara antibodies. Also, eosinophils in peripheral blood and the presence of other intestinal parasites were investigated. Results Seropositivity for T. canis was detected in 21 (23.3%) out of 90 schizophrenic patients and in one subject (2.2%) of 45 healthy controls (p< 0.01). When seropositive and seronegative schizophrenic patients were compared with respect to sex, residence, owning dogs / cats, history of geophagia, there was no significant differences between them (p> 0.05). In contrast, when they were compared with respect to raw food intake and personal hygiene, the differences were statistically significant (p< 0.05). Eosinophilia in peripheral blood was detected in 61.9% of seropositive schizophrenic patients and in 24.6% of seronegative schizophrenic patients (p< 0.01). Of 21 schizophrenic patients with positive serology, 47.6% had at least one intestinal parasite comparing to 20.3% in patients with negative serology (p< 0.05). Conclusion: There might be a causal relationship between toxocariasis and schizophrenia. Either Toxocara may be a possible etiologic agent of schizophrenia or the schizophrenic patients may be at high risk for Toxocara infection.