Toxoplasma gondii is known to have a complex life cycle and infect almost all kinds of warm-blooded animals around the world. The brain of the host could be persistently infected by cerebral cysts, and a variety of psychiatric disorders such as schizophrenia and suicide have been reported to be related with latent toxoplasmosis. The infected animals showed fear reduction and a tendency to be preyed upon. However, the mechanism of this “parasites manipulation” effects have not been elucidated. Here, we reviewed the recent infection prevalence of toxoplasmosis and the evidence of mental and behavioral disorders induced by T. gondii and discussed the related physiological basis including dopamine dysregulation and gamma-aminobutyric acid (GABA) pathway and the controversial opinion of the necessity for cerebral cysts existence. Based on the recent advances, we speculated that the neuroendocrine programs and neurotransmitter imbalance may play a key role in this process. Simultaneously, studies in the evaluation of the expression pattern of related genes, long noncoding RNAs (lncRNAs), and mRNAs of the host provides a new point for understanding the mechanism of neurotransmitter dysfunction induced by parasite manipulation. Therefore, we summarized the animal models, T. gondii strains, and behavioral tests used in the related epigenetic studies and the responsible epigenetic processes; pinpointed opportunities and challenges in future research including the causality evidence of human psychiatric disorders, the statistical analysis for rodent-infected host to be more vulnerable preyed upon; and identified responsible genes and drug targets through epigenetics.

Toxoplasma gondii (T. gondii) is widely spread around the world, which can cause serious harm to immunosuppressed patients. Currently, the commercial test kits are poor at assessing T. gondii infection and vaccine effectiveness, making an urgent need to exploit effective enzyme-linked immunosorbent assay with great performance to compensate for this deficiency. Here, the TgIMP1 recombinant protein was expressed in E. coli BL(21) cells. The TgIMP1 was purified with affinity chromatography and the reactivity was retained with anti-TgIMP1 antibodies. The TgIMP1 was then used to develop an indirect ELISA (IMP1-iELISA) and the reaction conditions of IMP1-iELISA were optimized. As a result, the cut-off value was determined to be 0.2833 by analyzing the OD_450nm values of forty T. gondii-negative sera. The coefficient of variation of 6 T. gondii-positive sera within and between runs were both less than 10%. The IMP1-iELISA was non-cross-reactive with the sera of cytomegalovirus, herpes virus, rubella virus, Cryptosporidium spp., Theileria spp., Neospora spp. and Plasmodium spp.. Furthermore, the sensitivity and specificity of IMP1-iELISA were 98.9% and 96.7%, respectively, based on testing 150 serum samples. The results suggest that this IMP1-iELISA is specific, sensitive, repeatable and can be applied to the detection of T. gondii infections in the medical and health industries.