[Survey on Toxoplasma gondii Infection in Depressed Patients and Genotype Identification in Guizhou Province]

To survey on Toxoplasma gondii infection in depressed patients in Guizhou Province and identify the genotype of T. gondii.

Enzyme-linked immunosorbent assay (ELISA) was applied to detect the T. gondii-specific antibodies IgG, IgM and circulating antigens (CAg) of T. gondii in 141 patients and 150 healthy subjects. The specific repeated DNA fragment (529 bp) of T. gondii was amplified by PCR. The genotype of T. gondii was determined by multiplex multilocus nested polymerase chain reaction-restriction fragment length polymorphism (Mn-PCR-RFLP).

ELISA showed that the positive rate of anti-T. gondii antibody in depressed patients and healthy subjects was 21.3%（30/141） and 7.3%（11/150）, respectively. The positive rate of IgG in depressed patients was 18.4% （26/141）, significantly higher than that in healthy subjects （7.3%, 11/150）（P<0.05）. The positive rate of IgM and CAg in depressed patients was both 1.4% （2/141）, while these were not found in healthy subjects. PCR revealed one patient positive for T. gondii, whose genotype was further identified to be Toxo DB #9（Chinese 1 type） by Mn-PCR-RFLP.

The positive rate of T. gondii is higher in depressed patients than in the healthy subjects in Guizhou Province. The genotype of T. gondii detected in one depressed patient is the Chinese 1 type.