Toxoplasma gondii Infection and Self-directed Violence in MothersToxoplasma Gondii and Self-directed Violence.
CONTEXT Two studies based on clinical samples have found an association between Toxoplasma gondii infection and history of suicide attempt. To our knowledge, these findings have never been replicated in a prospective cohort study. OBJECTIVE To examine whether T gondii-infected mothers have an increased risk of self-directed violence, violent suicide attempts, and suicide and whether the risk depends on the level of T gondii IgG antibodies. DESIGN Register-based prospective cohort study. Women were followed up from the date of delivery, 1992 to 1995 until 2006. SETTING Denmark. PARTICIPANTS A cohort of 45 788 women born in Denmark whose level of Toxoplasma-specific IgG antibodies was measured in connection with child birth between 1992 and 1995. MAIN OUTCOME MEASURES Incidence rates of self-directed violence, violent suicide attempts, and suicide in relation to T gondii seropositivity and serointensity. RESULTS T gondii-infected mothers had a relative risk of self-directed violence of 1.53 (95% CI, 1.27-1.85) compared with noninfected mothers, and the risk seemed to increase with increasing IgG antibody level. For violent suicide attempts, the relative risk was 1.81 (95% CI, 1.13-2.84) and for suicide, 2.05 (95% CI, 0.78-5.20). A similar association was found for repetition of self-directed violence, with a relative risk of 1.54 (95% CI, 0.98-2.39). CONCLUSION Women with a T gondii infection have an increased risk of self-directed violence.
[Show abstract] [Hide abstract] ABSTRACT: A recent study performed on 1.3 million patients showed a strong association between being bitten by a cat and probability of being diagnosed with depression. Authors suggested that infection with cat parasite Toxoplasma could be the reason for this association. A cross sectional internet study on a non-clinical population of 5,535 subjects was undertaken. The subjects that reported having been bitten by a dog and a cat or scratched by a cat have higher Beck depression score. They were more likely to have visited psychiatrists, psychotherapists and neurologists in past two years, to have been previously diagnosed with depression (but not with bipolar disorder). Multivariate analysis of models with cat biting, cat scratching, toxoplasmosis, the number of cats at home, and the age of subjects as independent variables showed that only cat scratching had positive effect on depression (p = 0.004). Cat biting and toxoplasmosis had no effect on the depression, and the number of cats at home had a negative effect on depression (p = 0.021). Absence of association between toxoplasmosis and depression and five times stronger association of depression with cat scratching than with cat biting suggests that the pathogen responsible for mood disorders in animals-injured subjects is probably not the protozoon Toxoplasma gondii but another organism; possibly the agent of cat-scratched disease – the bacteria Bartonella henselae.0Comments 0Citations
- "The oocystes of the parasite contained in feces of infected cats can survive in soil for many months; therefore, human infection can occur not only by direct contact with soil or consumption of unwashed vegetables, but also by soil on the paws and fur of both dogs and outdoor cats. Several studies have shown that Toxoplasma – infected subjects have higher levels of depression , anxiety  and a higher risk of suicide [5, 6] . It was suggested that decreased concentration of tryptophan and consequently serotonin – a part of the general defense of an organism against various infections – could be the reason for depression and possibly also for the increased rate of suicide in Toxoplasma-infected subjects . "
[Show abstract] [Hide abstract] ABSTRACT: The microbiome of the built environment (MoBE) is a relatively new area of study. While some knowledge has been gained regarding impacts of the MoBE on the human microbiome and disease vulnerability, there is little knowledge of the impacts of the MoBE on mental health. Depending on the specific microbial species involved, the transfer of microorganisms from the built environment to occupant's cutaneous or mucosal membranes has the potential to increase or disrupt immunoregulation and/or exaggerate or suppress inflammation. Preclinical evidence highlighting the influence of the microbiota on systemic inflammation supports the assertion that microorganisms, including those originating from the built environment, have the potential to either increase or decrease the risk of inflammation-induced psychiatric conditions and their symptom severity. With advanced understanding of both the ecology of the built environment, and its influence on the human microbiome, it may be possible to develop bioinformed strategies for management of the built environment to promote mental health. Here we present a brief summary of microbiome research in both areas and highlight two interdependencies including the following: (1) effects of the MoBE on the human microbiome and (2) potential opportunities for manipulation of the MoBE in order to improve mental health. In addition, we propose future research directions including strategies for assessment of changes in the microbiome of common areas of built environments shared by multiple human occupants, and associated cohort-level changes in the mental health of those who spend time in the buildings. Overall, our understanding of the fields of both the MoBE and influence of host-associated microorganisms on mental health are advancing at a rapid pace and, if linked, could offer considerable benefit to health and wellness.0Comments 1Citation
- "In immunosuppressed patients and during pregnancy its effects can be devastating. In immunocompetent hosts " latent " T. gondii infection has been associated with mental illness  and suicide  . Even in individuals with no evidence of mental illness, T. gondii seropositivity has been associated with gender-specific trait impulsivity and ag- gression  . "
[Show abstract] [Hide abstract] ABSTRACT: Although Toxoplasma gondii (T. gondii) infection is relevant to many psychiatric disorders, the fundamental mechanisms of its neurobiological correlation with depression are poorly understood. Here, we show that reactivation of chronic infection by an immunosuppressive regimen caused induction of depressive-like behaviors without obvious sickness symptoms. However, the depression-related behaviors in T. gondii-infected mice, specifically, reduced sucrose preference and increased immobility in the forced-swim test were observed at the reactivation stage, but not in the chronic infection. Interestingly, reactivation of T. gondii was associated with production of interferon-gamma and activation of brain indoleamine 2, 3-dioxygenase, which converts tryptophan to kynurenine and makes it unavailable for serotonin synthesis. Furthermore, serotonin turnover to its major metabolite, 5-hydroxyindoleacetic acid, was also enhanced at the reactivation stage. Thus, enhanced tryptophan catabolic shunt and serotonin turnover may be implicated in development of depressive-like behaviors in mice with reactivated T. gondii.0Comments 1Citation
- "As a mood disorder , depression is characterized by loss of interest, pleasure, cognitive function, sleep, appetite, and energy . Retrospective studies have referred to T. gondii seroprevalence in psychiatric disorders such as schizophrenia, bipolar mood disorder , and self-directed violence  . However, the causal link between T. gondii and bipolar disease is controversial, with some studies showing that T. gondii seroprevalence is not associated with major depressive disorder, generalized-anxiety disorder, or panic disorder . "