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Toxoplasma gondii & Human Phenotype

Compendium of Known Effects and Ongoing Research

bipolar disorder

Association between Toxoplasma gondii infection and psychiatric disorders in Zhejiang, Southeastern China

February 4, 2020
Chen, X. J., Chen, B., Hou, X. Q., Zheng, C. Q., Yang, X. J., Ke, J. Q., Hu, X., Tan, F.
Acta Tropica 2019, 192: 82 - 86
Click for abstract
Increased rates of exposure to Toxoplasma gondii have been found in patients with psychiatric disorders globally, but there is scarce information about the epidemiology of T. gondii infection in psychiatric patients in Zhejiang Province, Southeastern China. In a case-control survey, we measured IgG and IgM class antibodies against T. gondii in 798 patients from a public psychiatric hospital in the city of Wenzhou, Zhejiang Province, and in 681 non-psychiatric controls from the general population in the same region. Subjects in each group were matched by sex and age with an enzyme-linked immunoassay. Seroprevalence of anti-Toxoplasma IgG antibodies in psychiatric patients (13.3%, 106/798) was significantly higher than in the control population (9.4%, 64/681) (P = 0.022). Anti-Toxoplasma IgM antibodies were also significantly higher in the psychiatric patients (4.1%, 33/798) than in the control group (1.9%, 13/681) (P = 0.016). Additionally, we found significantly elevated seropositive rates of anti-Toxoplasma IgG and IgM in patients with schizophrenia, as well as those with bipolar disorder. The identification of specific anti-Toxoplasma antibodies in psychiatric patients may be useful for assessing infection and timely initiation of treatment.

Tagged: bipolar disorder, Toxoplasma gondii

Mental health

Lack of circulating toxoplasma gondii DNA in seropositive patients with bipolar or schizophrenia spectrum disorders

February 1, 2020
Galli, L., Del Grande, C. Rindi, L., Mangia, C., Mangano, V., Schiavi, E., Masci, I., Pinto, B., Kramer, L., Dell'Osso, L., Bruschi, F.
Psychiatry Research :2019, 173: 706 - 711
Click for abstract
Toxoplasmosis has been previously associated with an increased risk of having Schizophrenia or Bipolar disorder in several epidemiological studies. The aim of this observational, cross-sectional study was to examine the seroprevalence of Toxoplasma infection in a cohort of Italian psychiatric inpatients and to verify the presence of circulating Toxoplasma gondii DNA in the seropositive subjects. Sixty-three patients affected by bipolar or schizoaffective disorders according to DSM-5 criteria were enrolled. The presence of Toxoplasma infection was firstly examined using an indirect serological method (ELFA), and three different direct PCR-based methods were performed to detect circulating DNA in the seropositive patients. The seroprevalence of infection was 28.6%, with a significant association between higher age and the infection status. PCR, nested-PCR and Real-Time PCR revealed no positive samples for Toxoplasma gondii This result is in contrast with recent data from case-control studies that detected parasite genome in patients with different neuropsychiatric diagnosis without clinical evidence of acute toxoplasmosis. Our findings are to be interpreted with caution, because of the small sample size, the heterogeneity of enrolled patients and the observational nature of the study. Further studies are needed to better define the clinical features correlated to the seropositive status in neuropsychiatric patients.

Tagged: bipolar disorder, congenital, individuals, molecular diagnosis, nested pcr, pcr, population, risk factors, Rt-PCR, schizoaffective disorder, seroprevalence, Toxoplasma gondii, toxoplasmosis

Mental health

Toxoplasma gondii IgG associations with sleep-wake problems, sleep duration and timing

February 1, 2020
Corona, C. C. ,Zhang, M. Wadhawan, A., Daue, M. L., Groer, M. W., Dagdag, A., Lowry, C. A., Hoisington, A. J., Ryan, K. A., Stiller, J. W., Fuchs, D., Mitchell, B. D., Postolache, T. T.
Pteridines 2019, 30: 1 - 9
Click for abstract
Background: Evidence links Toxoplasma gondii (T. gondii), a neurotropic parasite, with schizophrenia, mood disorders and suicidal behavior, all of which are associated and exacerbated by disrupted sleep. Moreover, low-grade immune activation and dopaminergic overstimulation, which are consequences of T. gondii infection, could alter sleep patterns and duration. Methods: Sleep data on 833 Amish participants [mean age (SD) = 44.28 (16.99) years; 59.06% women] were obtained via self-reported questionnaires that assessed sleep problems, duration and timing. T. gondii IgG was measured with ELISA. Data were analyzed using multivariable logistic regressions and linear mixed models, with adjustment for age, sex and family structure. Results: T gondii seropositives reported less sleep problems (p < 0.005) and less daytime problems due to poor sleep (p < 0.005). Higher T. gondii titers were associated with longer sleep duration (p < 0.05), earlier bedtime (p < 0.005) and earlier mid-sleep time (p < 0.05). Conclusions: It seems unlikely that sleep mediates the previously reported associations between gondii and mental illness. Future longitudinal studies with objective measures are necessary to replicate our findings.

Tagged: bipolar disorder, gene-expression, igg, latent toxoplasmosis, mid sleep time, nitric oxide, Parkinson disease, risk factors, sleep duration, sleep timing, suicideattempts, Toxoplasma godnii, traffic accidents, tyrosine- hydroxylase

BehaviorMental health

Relationship between toxoplasmosis and obsessive compulsive disorder: A systematic review and meta-analysis

February 1, 2020
Nayeri Chegeni, T., Sarvi, S. Amouei, A. Moosazadeh, M. Hosseininejad, Z. Aghayan, S. A. Daryani, A.
PLoS Neglected Tropical Diseases 19, 13
Click for abstract
Background A few studies investigated the relationship between toxoplasmosis and mental disorders, such as obsessive compulsive disorder (OCD). However, the specific nature of the association between Toxoplasma gondii (T. gondii) infection and OCD is not yet clear. The aim of this study was to collect information on the relationship between OCD and toxoplasmosis and assess whether patients with toxoplasmosis are prone to OCD. Methods For the purpose of this study, 6 major electronic databases and the Internet search engine Google Scholar were searched for the published articles up to July 30(th), 2018 with no restriction of language. The inverse variance method and the random effect model were used to combine the data. The values of odds ratio (OR) were estimated at 95% confidence interval (CI). Results A total of 9 case-control and 3 cross-sectional studies were included in our systematic review. However, 11 of these 12 articles were entered into the meta-analysis containing 9873 participants, out of whom 389 were with OCD (25.96% positive for toxoplasmosis) and 9484 were without OCD (17.12% positive for toxoplasmosis). The estimation of the random effect model indicated a significant common OR of 1.96 [95% CI: 1.32-2.90]. Conclusion This systematic review and meta-analysis revealed that toxoplasmosis could be as an associated factor for OCD (OR = 1.96). However, further prospective investigations are highly recommended to illuminate the underlying pathophysiological mechanisms of T. gondii infection in OCD and to better investigate the relationship between OCD and T. gondii infection. Author summary Toxoplasma gondii (T. gondii) is an obligate neurotropic parasite that infected about 25-30% of the total human population in the developed and developing countries. The obsessive compulsive disorder (OCD) is a psychiatric disease that affects the income and quality of life. Some studies confirmed an association between infectious agents as the associated or protective factors specifying the development of psychiatry diseases. Among various pathogens associated with psychological disorders, most of the attention is on T. gondii, which has a life-long asymptomatic latent phase after a short acute stage in healthy individuals. The detrimental effect of T. gondii on immunocompromised people and pregnant women is an important concern for public health. The correlation between toxoplasmosis and OCD is still relatively understudied with a paucity of documented findings. The previous meta-analysis reviewed only two studies and reported a 3.4-fold greater chance of OCD. The results of our study presented stronger evidence of a positive relationship between toxoplasmosis and OCD. Eventually, our research team hopes to present an overview of what is known and encourage more intensive research to determine the real impact of this parasite on the occurrence of OCD that may contribute to the prevention of OCD worldwid

Tagged: antibodies, bipolar disorder, gondii infection, Schizophrenia, statement

Mental healthReviews

Is there any association between Toxoplasma gondii infection and depression? A systematic review and meta-analysis

January 31, 2020
Chegeni, T. N., Sharif, M., Sarvi, S., Moosazadeh, M., Montazeri, M., Aghayan, S. A., Balalami, N. J., Gholami, S., Hosseininejad, Z., Saberi, R., Anvari, D., Gohardehi, S., Daryani, A.
PLoS ONE 2019, 14
Click for abstract
Background Toxoplasma gondii (T. gondii) is an obligate intracellular opportunistic parasite that is the causative agent of toxoplasmosis. This parasite accounts for mental disorders; however, the relationship between T. gondii infection and depressive disorder is unclear. Regarding this, the present systematic review and meta-analysis was conducted to investigate the scientific evidence regarding the potential association between major depression disorder (MDD) and Toxoplasma infection. Methods For the purpose of the study, the articles related to the subject of interest were systematically searched in seven electronic databases. Special attention was given to the studies examining T. gondii seropositivity level in depressed patients and controls. Results The search process resulted in the identification of a total of 30 publications meeting the inclusion criteria and published up to April 2018 for the systematic review. Furthermore, 29 studies met the inclusion criteria to be entered into meta-analysis. Our meta-analysis involved the review of cross-sectional studies including 1657 depressed patients and 19565 individuals as controls and case-control studies entailing 1311 depressed cases and 6015 controls without depression. 1582 depressed people participated in cross-sectional studies whose results were reported as odds ratio (OR). In addition, the total number of participants was 15068 in this type of studies. Statistical analysis indicated that the pooled OR of the risk of anti-T. gondii IgG antibody in depressed individuals in case-control and cross-sectional studies was 1.15 (95% confidence interval (CI): 0.95-1.39). Conclusions As the findings of the reviewed articles indicated, toxoplasmosis is not a risk factor for MDD. However, it is necessary to perform further research to clarify the detailed association between T. gondii and dysthymia or mild and moderate depression. Furthermore, it is recommended to better investigate the effect of antibody titers on the relationship between depression and T. gondii infection.

Tagged: antibodies, behavior, bipolar disorder, prevalence, psychiatric patients, risk factors, Schizophrenia, suicide

Mental health

Seroprevalence and molecular evaluation of Toxoplasma gondii in Schizophrenic patients hospitalized in Sistan and Baluchestan province, Southeast of Iran

January 31, 2020
Modrek, M. J., Hasanzadeh, R., Foroutan, M., Mirahmadi, H., Rahmati-Balaghaleh, M., Zarean, M.
Tropical Biomedicine 19, 36: 422 - 429
Click for abstract
Over one-third of the world's population are seropositive for Toxoplasma gondii. One of the important traits of T. gondii is its ability to alter and manipulating the behavior and personality of its intermediate host. The current study was aimed to determine the prevalence of acute and chronic toxoplasmosis in those persons suffer from schizophrenia using serological and molecular techniques. In this cross-sectional study, blood samples were taken from 118 Schizophrenia patients hospitalized in Sistan and Baluchestan province, southeast of Iran. IgM and IgG anti-Toxoplasma antibodies were measured using enzyme-linked immunosorbent assay (ELISA). Furthermore, the presence of parasite was evaluated using nested-PCR BI gene. Among 118 schizophrenic patients, 48 (40.67%), 4 (3.37%) and 14 (11.86%) were tested seropositive only for IgG, only for IgM and for both of IgG/IgM. So that, total prevalence was 66/118 (55.91%). All samples were also examined using nested-PCR and T. gondii DNA was found in 41 (34.74%) samples. Our study showed high seroprevalence of toxoplasmosis in southeast of Iran.

Tagged: bipolar disorder, blood-donors, infection, metaanalysis, Toxoplasma gondii

Mental health

Host-parasite interaction associated with major mental illness

January 29, 2020
Kano, S., Hodgkinson, C. A., Jones-Brando, L., Eastwood, S., Ishizuka, K., Niwa, M., Choi, E. Y., Chang, D. J., Chen, Y., Velivela, S. D., Leister, F., Wood, J., Chowdari,K., Ducci, F., Caycedo, D. A., Heinz, E., Newman, E. R., Cascella, N., Mortensen, P. B., Zandi, P. P., Dickerson, F., Nimgaonkar, V., Goldman, D., Harrison, P. J., Yolken, R. H., Sawa, A.
Molecular Psychiatry 2020, 25: 194 - 205
Click for abstract
Clinical studies frequently report that patients with major mental illness such as schizophrenia and bipolar disorder have comorbid physical conditions, suggesting that systemic alterations affecting both brain and peripheral tissues might underlie the disorders. Numerous studies have reported elevated levels of anti-Toxoplasma gondii (T. gondii) antibodies in patients with major mental illnesses, but the underlying mechanism was unclear. Using multidisciplinary epidemiological, cell biological, and gene expression profiling approaches, we report here multiple lines of evidence suggesting that a major mental illness-related susceptibility factor, Disrupted in schizophrenia (DISC1), is involved in host immune responses against T. gondii infection. Specifically, our cell biology and gene expression studies have revealed that DISC1 Leu607Phe variation, which changes DISC1 interaction with activating transcription factor 4 (ATF4), modifies gene expression patterns upon T. gondii infection. Our epidemiological data have also shown that DISC1 607 Phe/Phe genotype was associated with higher T. gondii antibody levels in sera. Although further studies are required, our study provides mechanistic insight into one of the few well-replicated serological observations in major mental illness.

Tagged: bipolar disorder, brain, catechol-o-methyltransferase, genetic, olfactory cells, risk faktor, Schizophrenia, toxoplasma gondii infection

Mental health

Association between Toxoplasma gondii infection and psychiatric disorders in Zhejiang, Southeastern China

April 1, 2019
Chen, X., Chen, B., Hou, X., Zheng, C., Yang, X., Ke, J., Hu, X., Tan, F.
Acta Tropica, 192, 82–86. doi:10.1016/j.actatropica.2019.02.001
Click for abstract
Increased rates of exposure to Toxoplasma gondii have been found in patients with psychiatric disorders globally, but there is scarce information about the epidemiology of T. gondii infection in psychiatric patients in Zhejiang Province, Southeastern China. In a case-control survey, we measured IgG and IgM class antibodies against T. gondii in 798 patients from a public psychiatric hospital in the city of Wenzhou, Zhejiang Province, and in 681 non-psychiatric controls from the general population in the same region. Subjects in each group were matched by sex and age with an enzyme-linked immunoassay. Seroprevalence of anti-Toxoplasma IgG antibodies in psychiatric patients (13.3%, 106/798) was significantly higher than in the control population (9.4%, 64/681) (P= 0.022). Anti-Toxoplasma IgM antibodies were also significantly higher in the psychiatric patients (4.1%, 33/798) than in the control group (1.9%, 13/681) (P= 0.016). Additionally, we found significantly elevated seropositive rates of anti-Toxoplasma IgG and IgM in patients with schizophrenia, as well as those with bipolar disorder. The identification of specific anti-Toxoplasma antibodies in psychiatric patients may be useful for assessing infection and timely initiation of treatment.

Tagged: bipolar disorder, china, psychiatric-disorder, Schizophrenia, Toxoplasma gondii

Mental health

Toxoplasma antibody titers in mania: A cross sectional study

August 31, 2018
Mangot, A. G., Shivakumar, V., Saini, V., Subbanna, M., Kalmady, S. V., Venkatasubramanian, G.
Journal of Krishna Institute of Medical Sciences University 2018; 7: 13-20
Click for abstract
Background: Recent studies have found a role of infectious agents, especially Toxoplasma gondii, in pathology of bipolar disorder - mania. Aim and Objectives: This study was conducted with the aim to find the prevalence of toxoplasma antibody titers in Indian patients with mania and to assess its specificity towards the clinical profile. Material and Methods: Thirty-four patients having mania were recruited who were psychotropic naive/free, along with 74 healthy controls. Psychopathology was assessed using structured assessment scales. Serum concentration of Toxoplasma IgG was measured using Diesse Enzywell Toxoplasma IgG immunoassay kit. Results: Mann-Whitney U test revealed that the toxoplasma antibody levels were significantly higher in the mania group than healthy controls (U = 766.5, z = 3.25, p = 0.001). Spearman correlation analyses did not reveal any significant correlation between toxoplasma antibody levels and age at onset (n = 0.19, p = 0.26) or YMRS scores (n = 0.15, p = 0.39). Discussion: The herein reported association could have potential implications in better understanding the pathophysiology of mania and its treatment. This is the first study to evaluate the association between toxoplasma titers and mania in India with only a few studies done elsewhere in the world.

Tagged: bipolar, bipolar disorder, depression, disease, Dopamine, fatal attraction, gondii infection, individuals, mania, psychosis, risk factors, Schizophrenia, seroprevalence, Toxoplasma

Mental health

Immunoglobulin sub-class distribution in bipolar disorder and schizophrenia: potential relationship with latent Toxoplasma Gondii infection

August 31, 2018
Bengoufa, H. D., Godin, O., Doukhan, R., Guen, E. L.,Daban-Huard, C. , Bennabi, M., Delavest, M., Lepine, J. P., Boukouaci, W., Laouamri,H., Houenou, J., Jamain, S., Richard, J. R. , Lecorvosier, P. , Yolken, R., Rajagopal, K., Leboyer, M., Tamouza, R.
Bmc Psychiatry 2018; 18
Click for abstract
Background: Immune dysfunction could play a significant role in the pathogenesis of bipolar disorder (BD) and schizophrenia (SZ), conditions with an underlying pro-inflammatory state. Studies on humoral immune responses (which reflects antibody mediated fight against pathogens) in schizophrenia and bipolar disorder are sparse and often providing contradictory results. The aim of this study was to assess humoral immunity in a group of stable bipolar disorder and schizophrenia patients compared to controls by determining total Immunoglobulins and IgG subclasses and to assess their association with latent Toxoplasma gondii and/or CMV infection. Methods: 334 subjects (124 BD, 75 SZ and 135 Healthy Controls [HC]) were included and tested for humoral immunity by determining the total immunoglobulins (IgG,A and M) and IgG subclasses (IgG1, IgG2, IgG3, IgG4) and their relationship with latent Toxoplasma gondii infection, an established risk factor for BD and SZ. Results: Although lower levels of IgG, IgG1, IgG2, IgG4 and IgA were found among BD as compared to HC and/or SZ, after adjustment for confounding variables, only low levels of IgG and IgG1 in BD remai- ned significant. Strikingly highest levels of antibodies to T. gondii (but not CMV) infection in BD and SZ were associated with lowest levels of IgG3 and IgG4 levels as compared to controls. Conclusions: Schizophrenia and bipolar disorder patients with latent T. gondii specific infection may be more vulnerable to changes in immuno-inflammatory processes than controls with similar latent infectious state. Simultaneous sequential immunological monitoring both in steady state and active disease phases in the same BD and SZ patients are warranted to understand the role of Toxoplasma gondii latency in these disorders.

Tagged: antibodies, association, bipolar disorder, cognitive deficits, gondii, humoral immunity, immunoglobulins, individuals, inflammation, metaanalysis, risk, scale, Schizophrenia, Toxoplasma gondii

Mental health

Are infectious agents involved in the pathogenesis of postpartum psychosis?

May 3, 2018
de Witte, L.D., Snijders, G., Litjens, M., Kamperman, A.M., Kushner, S.A., Kahn, R.S., Bergink, V.
Journal of Affective Disorders 2018; 229: 141-144
Click for abstract
Background: Since postpartum psychosis has been linked to activation of the immune system, it has been hypothesized that infectious agents may be involved in the pathogenesis of this disorder. We therefore investigated whether exposure to pathogens that can infect the central nervous system is increased in patients with postpartum psychosis. Methods: We measured the prevalence and titers of immunoglobulin G (IgG) and M (IgM) to herpes simplex virus type 1 (HSV-1) and 2 (HSV-2), Epstein-Barr virus (EBV), cytomegalovirus (CMV) and Toxoplasma Gondii (TG) in a cohort of patients with postpartum psychosis (n = 81) and compared these to matched postpartum controls. Results: We did not find significant differences in seroprevalence or antibody titers for any of these pathogens. Limitations: Limitations of this study include the indirect measurement of infectious disease and the cross-sectional design. Conclusion: Our results do not support the hypothesis that exposure to these neurotropic pathogens is involved in postpartum psychosis.

Tagged: bipolar disorder, depression, encephalitis, herpes-simplex, metaanalyses, risk factors, Schizophrenia, Toxoplasma gondii

Mental health

Toxoplasma gondii: Biological parameters of the connection to schizophrenia

February 12, 2018
Xiao, J. C. ,Prandovszky, E. , Kannan,G., Pletnikov, M. V. Dickerson, ,F. , Severance , E. G., Yolken, R. H.
Schizophrenia Bulletin 2018; 44: 983-992
Click for abstract
It is increasingly evident that the brain is not truly an immune privileged site and that cells of the central nervous system are sensitive to the inflammation generated when the brain is fighting off infection. Among the many microorganisms that have access to the brain, the apicomplexan protozoan Toxoplasma gondii has been one of the most studied. This parasite has been associated with many neuropsychiatric disorders including schizophrenia. This article provides a comprehensive review of the status of Toxoplasma research in schizophrenia. Areas of interest include (1) the limitations and improvements of immune-based assays to detect these infections in humans, (2) recent discoveries concerning the schizophrenia-Toxoplasma association, (3) findings of Toxoplasma neuropathology in animal models related to schizophrenia pathogenesis, (4) interactions of Toxoplasma with the host genome, (5) gastrointestinal effects of Toxoplasma infections, and (6) therapeutic intervention of Toxoplasma infections.

Tagged: attempts, bipolar disorder, complement c1q, congenital toxoplasmosis, immune activation, infection, microorganism, molecular-mechanisms, murine toxoplasmosis, pathogenesis, psychiatric-disorders, risk factors, suicide, tissue cyst formation

Mental health

Immunoglobulin sub-class distribution in bipolar disorder and schizophrenia: potential relationship with latent Toxoplasma Gondii infection

February 12, 2018
Hamdani,N. ,Bengoufa, D. , Godin, O., Doukhan, R.., Le Guen,E., Daban-Huard, C. , Bennabi, M. ,Delavest, M., Lepine, J. P., Boukouaci, W. , Laouamri, H. , Houenou,J., Jamain, S., Richard,J. R. , Lecorvosier, P. , Yolken,R. , Rajagopal, K. , Leboyer, M. , Tamouza, R.
BMC Psychiatry,10.1186/s12888-018-1821-9, Article Number 239
Click for abstract
Background: Immune dysfunction could play a significant role in the pathogenesis of bipolar disorder (BD) and schizophrenia (SZ), conditions with an underlying pro-inflammatory state. Studies on humoral immune responses (which reflects antibody mediated fight against pathogens) in schizophrenia and bipolar disorder are sparse and often providing contradictory results. The aim of this study was to assess humoral immunity in a group of stable bipolar disorder and schizophrenia patients compared to controls by determining total Immunoglobulins and IgG subclasses and to assess their association with latent Toxoplasma gondii and/or CMV infection. Methods: 334 subjects (124 BD, 75 SZ and 135 Healthy Controls [HC]) were included and tested for humoral immunity by determining the total immunoglobulins (IgG,A and M) and IgG subclasses (IgG1, IgG2, IgG3, IgG4) and their relationship with latent Toxoplasma gondii infection, an established risk factor for BD and SZ. Results: Although lower levels of IgG, IgG1, IgG2, IgG4 and IgA were found among BD as compared to HC and/or SZ, after adjustment for confounding variables, only low levels of IgG and IgG1 in BD remai- ned significant. Strikingly highest levels of antibodies to T. gondii (but not CMV) infection in BD and SZ were associated with lowest levels of IgG3 and IgG4 levels as compared to controls. Conclusions: Schizophrenia and bipolar disorder patients with latent T. gondii specific infection may be more vulnerable to changes in immuno-inflammatory processes than controls with similar latent infectious state. Simultaneous sequential immunological monitoring both in steady state and active disease phases in the same BD and SZ patients are warranted to understand the role of Toxoplasma gondii latency in these disorders.

Tagged: antibodies, association, bipolar disorder, cognitive deficits, gondii, humoral immunity, immunoglobulins, individuals, inflammation, metaanalysis, risk, scale, Schizophrenia, Toxoplasma gondii herpes-simplex-virus

Mental health

Neurophysiological changes induced by chronic Toxoplasma gondii infection

December 8, 2017
Tedford, E., McConkey, G.
Pathogens 2017; 6: Artn 19 10.3390/Pathogens6020019
Click for abstract
Although the parasite Toxoplasma gondii is one of the most pervasive neurotropic pathogens in the world, the host-parasite interactions during CNS infection and the consequences of neurological infection are just beginning to be unraveled. The chronic stages of infection have been considered dormant, although several studies have found correlations of infection with an array of host behavioral changes. These may facilitate parasite transmission and impact neurological diseases. During infection, in addition to the presence of the parasites within neurons, host-mediated neuroimmune and hormonal responses to infection are also present. T. gondii induces numerous changes to host neurons during infection and globally alters host neurological signaling pathways, as discussed in this review. Understanding the neurophysiological changes in the host brain is imperative to understanding the parasitic mechanisms and to delineate the effects of this single-celled parasite on health and its contribution to neurological disease

Tagged: alzheimers-disease, bipolar disorder, central-nervous-system, gene-expression, host-parasite interaction, immune system, infection, Neurophysiology, Toxoplasma gondii

BehaviorMental health

Toxoplasma gondii and schizophrenia: a review of published RCTs

October 2, 2017
Chorlton, S.D.
Parasitology Research 2017; 116: 1793-1799
Click for abstract
Over the last 60 years, accumulating evidence has suggested that acute, chronic, and maternal Toxoplasma gondii infections predispose to schizophrenia. More recent evidence suggests that chronically infected patients with schizophrenia present with more severe disease. After acute infection, parasites form walled cysts in the brain, leading to lifelong chronic infection and drug resistance to commonly used antiparasitics. Chronic infection is the most studied and closely linked with development and severity of schizophrenia. There are currently four published randomized controlled trials evaluating antiparasitic drugs, specifically azithromycin, trimethoprim, artemisinin, and artemether, in patients with schizophrenia. No trials have demonstrated a change in psychopathology with adjunctive treatment. Published trials have either selected drugs without evidence against chronic infection or used them at doses too low to reduce brain cyst burden. Furthermore, trials have failed to achieve sufficient power or account for confounders such as previous antipsychotic treatment, sex, age, or rhesus status on antiparasitic effect. There are currently no ongoing trials of anti-Toxoplasma therapy in schizophrenia despite ample evidence to justify further testing.

Tagged: antibodies, artemisinin, azithromycin, bipolar disorder, chronic, efficacy, infection, metaanalysis, mice, minocycline, Schizophrenia, Toxoplasma, treatment, trimethoprim

Mental health

From toxoplasmosis to schizophrenia via nMda dysfunction: peptide overlap between Toxoplasma gondii and N-Methyl-D-aspartate receptors as a potential Mechanistic Link.

October 2, 2017
Lucchese, G.
Frontiers in Psychiatry 2017; 8
Click for abstract
The present work aims at investigating how Toxoplasma gondii (T. gondii) infection may be linked to N-methyl-D-aspartate receptor (NMDAR) dysfunction in schizophrenia and related disorders and puts forward the hypothesis that immune responses against T. gondii may involve NMDARs. Indeed, the analysis of the protozoan proteome and NMDAR subunits for peptide commonalities shows a massive peptide overlap and supports the possibility that anti-T. gondii immune responses raised during active protozoan infection may cross-react with host NMDARs, determining disruption of neural circuits and cognitive deficits. In particular, the NMDA 2D subunit, which is mainly expressed in parvalbumin-positive interneurons, appears to be a hotspot for potential T. gondii-induced cross-reactive immune attacks.

Tagged: bipolar disorder, brain activity rat-brain antibodies, gamma oscillations, glun2d subunit, glutamate-receptor, hippocampal interneurons, immune crossreactivity, ketamine, n-methyl-d-aspartate receptors, neural oscillations, nmda 2d, parvalbumin-positive interneurons, peptide commonality, Schizophrenia, Toxoplasma gondii

Mental health

Relationship between Toxoplasma gondii seropositivity and acoustic startle response in an inner-city population

October 2, 2017
Massa, N. M., Duncan, E., Jovanovic, T., Kerley, K., Weng, L., Gensler, L., Lee, S. S., Norrholm, S., Powers, A., Almli, L. M., Gillespie, C. F., Ressler, K., Pearce, B. D.,
Brain Behavior and Immunity 2017; 61: 176-183
Click for abstract
Toxoplasma gondii (TOXO) is a neuroinvasive protozoan parasite that induces the formation of persistent cysts in mammalian brains. It infects approximately 1.1 million people in the United States annually. Latent TOXO infection is implicated in the etiology of psychiatric disorders, especially schizophrenia (SCZ), and has been correlated with modestly impaired cognition. The acoustic startle response (ASR) is a reflex seen in all mammals. It is mediated by a simple subcortical circuit, and provides an indicator of neural function. We previously reported the association of TOXO with slowed acoustic startle latency, an index of neural processing speed, in a sample of schizophrenia and healthy control subjects. The alterations in neurobiology with TOXO latent infection may not be specific to schizophrenia. Therefore we examined TOXO in relation to acoustic startle in an urban, predominately African American, population with mixed psychiatric diagnoses, and healthy controls. Physiological and diagnostic data along with blood samples were collected from 364 outpatients treated at an inner-city hospital. TOXO status was determined with an ELISA assay for TOXO-specific IgG. A discrete titer was calculated based on standard cut-points as an indicator of seropositivity, and the TOXO-specific IgG concentration served as serointensity. A series of linear regression models were used to assess the association of TOXO seropositivity and serointensity with ASR magnitude and latency in models adjusting for demographics and psychiatric diagnoses (PTSD, major depression, schizophrenia, psychosis, substance abuse). ASR magnitude was 11.5% higher in TOXO seropositive subjects compared to seronegative individuals (p = 0.01). This effect was more pronounced in models with TOXO serointensity that adjusted for sociodemographic covariates (F = 7.41, p = 0.0068; F = 10.05, p = 0.0017), and remained significant when psychiatric diagnoses were stepped into the models. TOXO showed no association with startle latency (t = 0.49, p = 0.63) in an unadjusted model, nor was TOXO associated with latency in models that included demographic factors. After stepping in individual psychiatric disorders, we found a significant association of latency with a diagnosis of PTSD (F = 5.15, p = 0.024), but no other psychiatric diagnoses, such that subjects with PTSD had longer startle latency. The mechanism by which TOXO infection is associated with high startle magnitude is not known, but possible mechanisms include TOXO cyst burden in the brain, parasite recrudescence, or molecular mimicry of a host epitope by TOXO. Future studies will focus on the neurobiology underlying the effects of latent TOXO infection as a potential inroad to the development of novel treatment targets for psychiatric disease.

Tagged: acoustic startle response, association, bipolar disorder, human personality, infection, latent toxoplasmosis, mental health, posttraumatic-stress-disorder, prepulse inhibition, ptsd, risk factors, Schizophrenia, substance use disorder, Toxoplasma gondii, united-states

Cognitive functionsMotor functions

Prevalence of Toxoplasma infection in first episode schizophrenia and bipolar disorder: Comparison between Toxoplasma seropositive and Toxoplasma seronegative groups.

October 2, 2017
Solanki, R.K., Singh, C., Mishra, V.
Indian Journal of Psychiatry 2017; 59: S212-S212
Tagged: bipolar disorder, Schizophrenia, Toxoplasma

Mental health

Systematic assessment of environmental risk factors for bipolar disorder: an umbrella review of systematic reviews and meta-analyses

May 11, 2017
Bortolato, B., Kohler, C.A., Evangelou, E., Leon-Caballero, J., Solmi, M., Stubbs, B., Belbasis, L., Pacchiarotti, I., Kessing, L.V., Berk, M., Vieta, E., Carvalho, A.F.
Bipolar Disorder 2017; 19: 84-96
Click for abstract
ObjectivesThe pathophysiology of bipolar disorder is likely to involve both genetic and environmental risk factors. In our study, we aimed to perform a systematic search of environmental risk factors for BD. In addition, we assessed possible hints of bias in this literature, and identified risk factors supported by high epidemiological credibility. MethodsWe searched the Pubmed/MEDLINE, EMBASE and PsycInfo databases up to 7 October 2016 to identify systematic reviews and meta-analyses of observational studies that assessed associations between putative environmental risk factors and BD. For each meta-analysis, we estimated its summary effect size by means of both random- and fixed-effects models, 95% confidence intervals (CIs), the 95% prediction interval, and heterogeneity. Evidence of small-study effects and excess of significance bias was also assessed. ResultsSixteen publications met the inclusion criteria (seven meta-analyses and nine qualitative systematic reviews). Fifty-one unique environmental risk factors for BD were evaluated. Six meta-analyses investigated associations with a risk factor for BD. Only irritable bowel syndrome (IBS) emerged as a risk factor for BD supported by convincing evidence (k=6; odds ratio [OR]=2.48; 95% CI=2.35-2.61; P<.001), and childhood adversity was supported by highly suggestive evidence. Asthma and obesity were risk factors for BD supported by suggestive evidence, and seropositivity to Toxoplasma gondii and a history of head injury were supported by weak evidence. ConclusionsNotwithstanding that several environmental risk factors for BD were identified, few meta-analyses of observational studies were available. Therefore, further well-designed and adequately powered studies are necessary to map the environmental risk factors for BD.

Tagged: aetiology, bipolar disorder, depression, mania, meta-analysis, mood disorder, psychiatry, Risk factor, systematic review

Mental healthReviews

Pathogen-mediated NMDA receptor autoimmunity and cellular barrier dysfunction in schizophrenia

May 9, 2017
Kannan, G., Gressitt, K.L., Yang, S., Stallings, C.R., Katsafanas, E., Schweinfurth, L.A., Savage, C.L.G., Adamos, M.B., Sweeney, K.M., Origoni, A.E., Khushalani, S., Bahn, S., Leweke, F.M., Dickerson, F.B., Yolken, R.H., Pletnikov, M.V., Severance, E.G.
Translational Psychiatry 2017; 7: 10.1038/tp.2017.162
Click for abstract
Autoantibodies that bind the N-methyl-D-aspartate receptor (NMDAR) may underlie glutamate receptor hypofunction and related cognitive impairment found in schizophrenia. Exposure to neurotropic pathogens can foster an autoimmune-prone environment and drive systemic inflammation leading to endothelial barrier defects. In mouse model cohorts, we demonstrate that infection with the protozoan parasite, Toxoplasma gondii, caused sustained elevations of IgG class antibodies to the NMDAR in conjunction with compromised blood-gut and blood-brain barriers. In human cohorts, NMDAR IgG and markers of barrier permeability were significantly associated with T. gondii exposure in schizophrenia compared with controls and independently of antipsychotic medication. Combined T. gondii and NMDAR antibody seropositivity in schizophrenia resulted in higher degrees of cognitive impairment as measured by tests of delayed memory. These data underscore the necessity of disentangling the heterogeneous pathophysiology of schizophrenia so that relevant subsets eligible for NMDAR-related treatment can be identified. Our data aid to reconcile conflicting reports regarding a role of pathological NMDAR autoantibodies in this disorder.

Tagged: bipolar disorder, celiac-disease, glutamate-receptor, human-behavior, immune activation, increased prevalence, latent toxoplasmosis, lupus autoantibodies, S100B protein, Toxoplasma gondii

BehaviorMental health

Toxoplasma gondii seroprevalence in a cohort of Italian psychiatric inpatients with mood or psychotic disorders: a preliminary communication

May 4, 2017
Del Grande, C., Schiavi, E., Masci, I., Barbuti, M., Maccariello, G., Pinto, B., Massimetti, G., Bruschi, F. , Dell’Osso, L.
European Neuropsychopharmacology 2017; 27: 881-882
Tagged: bipolar disorder, metaanalysis, Schizophrenia

Mental health

Evidence of increased exposure to Toxoplasma gondii in individuals with recent onset psychosis but not with established schizophrenia

May 4, 2017
Yolken, R., Torrey, E.F., Dickerson, F.
PLOS Neglected Tropical Diseases 2017; 10.1371/journal.pntd.0006040
Click for abstract
AB A possible role for Toxoplasma gondii in the etiopathogenesis of schizophrenia is supported by epidemiological studies and animal models of infection. However, recent studies attempting to link Toxoplasma to schizophrenia have yielded mixed results. We performed a nested case-control study measured serological evidence of exposure to Toxoplasma gondii in a cohort of 2052 individuals. Within this cohort, a total of 1481 individuals had a psychiatric disorder and 571 of were controls without a psychiatric disorder. We found an increased odds of Toxoplasma exposure in individuals with a recent onset of psychosis (OR 2.44, 95% Confidence Interval 1.4-4.4, p < .003). On the other hand, an increased odds of Toxoplasma exposure was not found in individuals with schizophrenia or other psychiatric disorder who did not have a recent onset of psychosis. By identifying the timing of evaluation as a variable, these findings resolve discrepancies in previous studies and suggest a temporal relationship between Toxoplasma exposure and disease onset.

Tagged: antibodies, association, bipolar disorder, drugs, immunoglobulin-g, infections, metaanalysis, sample

Mental health

The association between immune markers and recent suicide attempts in patients with serious mental illness: A pilot study

March 23, 2017
Dickerson, F., Adamos, M., Katsafanas, E., Khushalani, S., Origoni, A., Savage, C., Schweinfurth, L., Stallings, C., Sweeney, K., Alaedini, A., Uhde, M., Severance, E., Wilcox, H. C., Yolken, R.
Psychiatry Research 2017;255:8-12
Click for abstract
Previous studies have identified elevations in markers of gastrointestinal inflammation in schizophrenia and mood disorders but studies have not measured the association between these markers and recent suicide attempts. We assessed 210 patients receiving treatment for schizophrenia, bipolar disorder, or major depression. We employed the Columbia Suicide Severity Rating Scale to identify recent and lifetime suicide attempts (actual, aborted, and interrupted). Psychiatric participants and a control group of 72 individuals without a psychiatric disorder had a blood sample drawn from which were measured specific markers of gastrointestinal inflammation and also C-Reactive protein (CRP). A total of 20 (10%) of psychiatric participants had a suicide attempt in the previous one month and 95 (45%) an attempt during their lifetime but not in the previous one month. The recent attempters had significantly elevated levels of antibodies to yeast mannan from Saccharomyces cerevisiae (ASCA), the food antigen gliadin, and bacterial lipopolysaccharide (LPS) compared with the non-psychiatric group when adjusting for demographic and clinical variables. These markers were not elevated in individuals with a past, but not recent, suicide attempt history. Our study indicates that there is evidence of gastrointestinal inflammation in some individuals who have had a recent suicide attempt.

Tagged: activation, attempted, biomarkers, bipolar disorder, celiac-disease, gastrointestinal, inflammation, inflammatory-bowel-disease, metaanalysis, psychiatric-disorders, rating-scale, Schizophrenia, sensitivity, suicide, Toxoplasma gondii

Mental health

Neurophysiological changes induced by chronic Toxoplasma gondii Infection.

March 13, 2017
Tedford, E., McConkey, G.
Pathogens. 2017; 6: 19-31
Click for abstract
Although the parasite Toxoplasma gondii is one of the most pervasive neurotropic pathogens in the world, the host-parasite interactions during CNS infection and the consequences of neurological infection are just beginning to be unraveled. The chronic stages of infection have been considered dormant, although several studies have found correlations of infection with an array of host behavioral changes. These may facilitate parasite transmission and impact neurological diseases. During infection, in addition to the presence of the parasites within neurons, host-mediated neuroimmune and hormonal responses to infection are also present. T. gondii induces numerous changes to host neurons during infection and globally alters host neurological signaling pathways, as discussed in this review. Understanding the neurophysiological changes in the host brain is imperative to understanding the parasitic mechanisms and to delineate the effects of this single-celled parasite on health and its contribution to neurological disease.

Tagged: alzheimers-disease, bipolar disorder, catecholamine, central-nervous-system, dendritic cells, dependent manner, DNA, Dopamine, gamma-interferon, gene-expression, glutamatergic, host-parasite interaction, immune system, infection, methylation, neuroimmune, Neurophysiology, parasitic, testosterone, Toxoplasma gondii

Mental health

Infection and inflammation in schizophrenia and bipolar disorder

January 3, 2017
Tanaka, T., Matsuda, T., Hayes, L. N., Yang, S. J., Rodriguez, K., Severance, E. G., Yolken, R. H., Sawa, A., Eaton, W. W.
Neuroscience Research 2017; 115: 59-63
Click for abstract
The present study investigated the relationship between exposure to infectious agents and inflammation markers in individuals with schizophrenia (SZ), bipolar disorder (BP), and controls without a psychiatric disorder. We measured plasma levels of antibodies and innate immune markers and correlated them with clinical symptoms and cognitive function. In both SZ and BP, we found an increase in soluble CD14, and in BP an increase in C-reactive protein, IgM class antibodies against cytomegalovirus (CMV), and IgG class antibodies against herpes simplex virus 2. Furthermore in BP, we observed a negative relationship between IgG antibodies against CMV and scores for cognitive function. (C) 2016 Elsevier Ireland Ltd and Japan Neuroscience Society. All rights reserved.

Tagged: agents, antibodies, antibody level, bipolar disorder, cognitive deficits, glial tnf-alpha, individuals, inflammation, markers, metaanalysis, neurocognition, recent-onset schizophrenia, Schizophrenia, synapses, Toxoplasma gondii

Mental health

Bipolar disorder with psychotic features and ocular toxoplasmosis

January 3, 2017
Del Grande, C., Contini, C., Schiavi, E., Rutigliano, G., Maritati, M., Seraceni, S., Pinto, B., Dell'Osso, L., Bruschi, F.
Journal of Nervous and Mental Disease 2017; 205: 192-195
Click for abstract
Recent evidence suggests the involvement of Toxoplasma gondii infection in the emergence of psychotic and affective disorders. In this report, we describe the case of a young Brazilian woman affected by recurrent ocular toxoplasmosis and presenting with a manic episode with psychotic features in the context of a diagnosis of Bipolar Disorder (BD), type I. We observed a relationship between ocular manifestations and the clinical course of bipolar illness, confirmed by molecular analyses (nested-PCR), as well as by the high level of T. gondii specific IgG. This case report is the first showing the presence of circulating parasite DNA at the time of occurrence of psychiatric symptoms, thus providing further support for a possible role of the parasite in the pathogenesis of some cases of BD.

Tagged: antibodies, bipolar disorder, gondii infection, individuals, metaanalysis, mood disorders, nested pcr, ocular toxoplasmosis, psychosis, rating-scale, retinochoroiditis, Schizophrenia, seropositivity, suicide attempts, toxoplasma gondii infection

Mental health

Suicide attempts and markers of immune response in individuals with serious mental illness

January 3, 2017
Dickerson, F., Wilcox, H. C., Adamos, M., Katsafanas, E., Khushalani, S., Origoni, A., Savage, C., Schweinfurth, L., Stallings, C., Sweeney, K., Yolken, R.
Journal of Psychiatric Research 2017; 87: 37-43
Click for abstract
Previous studies have identified elevations in antibodies to Toxoplasma gondii in individuals with a history of suicide attempts but studies have not measured the association between suicide attempts and a panel of antibody markers. We assessed 162 patients receiving treatment for schizophrenia, bipolar disorder, or major depression on the Columbia Suicide Severity Rating Scale for suicide attempt history and other clinical measures. All participants had a blood sample drawn from which were measured antibodies to Toxoplasma gondii and other neurotropic infectious agents. A total of 72 (44%) of participants had a lifetime suicide attempt; these individuals had elevated levels of IgM class antibodies to Toxoplasma gondii and Cytomegalovirus (CMV). We also found an association between the levels of these antibodies and the number of suicide attempts. There was a particularly strong odds of a suicide attempt history in individuals who had elevated levels of IgM antibodies to both Toxoplasma gondii and to CMV suggesting an additive risk associated with the antibodies. These findings remained significant when adjusting for current cigarette smoking and history of drug/alcohol use which were also associated with suicide attempts. We did not find an association between a suicide attempt history and IgG class antibodies to Toxoplasma gondii, CMV, or IgM or IgG antibodies to the Epstein Barr Virus or other antigens tested. The identification of blood-based antibody markers should provide for more personalized methods for the assessment and treatment, and ultimately prevention, of suicide attempts in individuals with serious mental illnesses. (C) 2016 Elsevier Ltd. All rights reserved.

Tagged: barr-virus infection, biomarkers, bipolar disorder, cytomegalovirus-infection, immunoglobulin-m antibodies, psychological autopsy, rating-scale, risk factors, Schizophrenia, suicide, toll-like receptors, Toxoplasma, toxoplasma gondii infection

Mental health

Infectious and immunogenetic factors in bipolar disorder

January 3, 2017
Oliveira, J., Oliveira-Maia, A. J., Tamouza, R., Brown, A. S., Leboyer, M.
Acta Psychiatrica Scandinavica 2017; 136:409-423
Click for abstract
Objective: Despite the evidence supporting the association between infection and bipolar disorder (BD), the genetic vulnerability that mediates its effects has yet to be clarified. A genetic origin for the immune imbalance observed in BD, possibly involved in the mechanisms of pathogen escape, has, however, been suggested in recent studies. Method: Here, we present a critical review based on a systematic literature search of articles published until December 2016 on the association between BD and infectious/immunogenetic factors. Results: We provide evidence suggesting that infectious insults could act as triggers of maladaptive immune responses in BD and that immunogenetic vulnerability may amplify the effects of such environmental risk factors, increasing susceptibility to subsequent environmental encounters. Quality of evidence was generally impaired by scarce attempt of replication, small sample sizes and lack of high-quality environmental measures. Conclusion: Infection has emerged as a potential preventable cause of morbidity in BD, urging the need to better investigate components of the host-pathogen interaction in patients and at-risk subjects, and thus opening the way to novel therapeutic opportunities.

Tagged: antagonist gene polymorphism, bipolar disorder, borna-disease virus, immunogenetics, infection, inflammation, korean population, manic-depressive disorders, mood disorders, necrosis-factor-alpha, population-based cohort, retrovirus-w family, severe mental illness, toxoplasma gondii infection

Mental health

Temporal cognitive decline associated with exposure to infectious agents in a population-based, aging cohort

October 29, 2016
Nimgaonkar, V. L., Yolken, R. H., Wang, T. X., Chang, C. C. H., McClain, L., McDade, E., Snitz, B. E., Ganguli, M
Alzheimer Disease & Associated Disorders 2016; 30: 216-222
Click for abstract
Background:Numerous cross-sectional studies have related exposure to neurotropic infectious agents with cognitive dysfunction in older adults, however, the temporal sequence is uncertain.Methods:In a representative, well-characterized, population-based aging cohort, we determined whether the temporal trajectories of multiple cognitive domains are associated with exposure to cytomegalovirus (CMV), Herpes Simplex virus, type 1 (HSV-1), Herpes Simplex virus, type 2 (HSV-2), or Toxoplasma gondii (TOX). Complex attention, executive functions, memory, language, and visuospatial function were assessed annually for 5 years among consenting individuals. Study entry IgG antibody titers indexing exposure to each infectious agent were examined in relation to slopes of subsequent temporal cognitive decline using multiple linear regressions adjusted for potential confounders.Results:The IgG levels for HSV-2 were significantly associated with baseline cognitive domain scores (N=1022 participants). Further, the IgG levels for HSV-2, TOX, and CMV, but not HSV-1 were significantly associated with greater temporal cognitive decline that varied by type of infection.Conclusions:Exposure to CMV, HSV-2, or TOX is associated with cognitive deterioration in older individuals, independent of general age-related variables. An increased understanding of the role of infectious agents in cognitive decline may lead to new methods for its prevention and treatment.

Tagged: aging, antibodies, bipolar disorder, CMV, cognition, community, cytomegalovirus, disease, Epidemiology, herpes virus, impairment, persistent infection, Schizophrenia, simplex-virus type-1, Toxoplasma gondii, viral-infections

Cognitive functions

The known and missing links between Toxoplasma gondii and schizophrenia

October 6, 2016
Elsheikha, H.M., Busselberg, D., Zhu, X.Q.
Metabolic Brain Disease 2016; 31: 749-759.
Click for abstract
Toxoplasma gondii, an intracellular protozoan parasite, has a striking predilection for infecting the Central Nervous System and has been linked to an increased incidence of a number of psychiatric diseases. Several in vitro and in vivo studies have shown that T. gondii infection can affect the structure, bioenergetics and function of brain cells, and alters several host cell processes, including dopaminergic, tryptophan-kynurenine, GABAergic, AKT1, Jak/STAT, and vasopressinergic pathways. These mechanisms underlying the neuropathology of latent toxoplasmosis seem to operate also in schizophrenia, supporting the link between the two disorders. Better understanding of the intricate parasite-neuroglial communications holds the key to unlocking the mystery of T. gondii-mediated schizophrenia and offers substantial prospects for the development of disease-modifying therapies.

Tagged: bipolar disorder, c-reactive protein, cell-cultures, central-nervous-system, Dopamine, host-pathogen, infected mice, interaction, interferon-gamma, long-term potentiation, mental illness, obsessive-compulsive disorder, oxidative stress, psychosis, Schizophrenia, Toxoplasma gondii

Mental health

Toxoplasma gondii infection in schizophrenia and associated clinical features

October 6, 2016
Esshili, A., Thabet, S., Jemli, A., Trifa, F., Mechri, A., Zaafrane, F., Gaha, L., Juckel, G., Babba, H., Jrad, B. B. H.
Psychiatry Research 2016; 245: 327-332
Click for abstract
The belief that latent toxoplasmosis is asymptomatic has been questioned, in particular due to the repeated highlighted link between the Toxoplasma gondii infection and an increased incidence of schizophrenia. However, to understand this relationship, the effect of infection with Toxoplasma gondii on the severity of schizophrenia has been poorly studied. Our work focused on comparing the prevalence of Toxoplasma infection between schizophrenic patients and healthy controls, as well as comparing the clinical features and the demographic characteristics between Toxoplasma-seronegative and Toxoplasma-seropositive patients with schizophrenia. The rate of IgG antibody in the schizophrenia patients was 74.8% compared 53.8% in controls. Patients with schizophrenia had a significantly higher mean of serum IgG antibodies to T. gondii compared to controls. The seropositive male patients had a higher age of disease onset, a higher BPRS score, a greater negative PANSS score and a lower GAF score than the seronegative male patients. These results suggest a higher severity of clinical symptoms in the male patients with schizophrenia. This study provides further evidence to the hypothesis that exposure to Toxoplasma may be a risk factor for schizophrenia. Moreover, toxoplasmosis in men with schizophrenia may lead to more severe negative and cognitive symptoms and a less favorable course of schizophrenia.

Tagged: adult, bipolar disorder, bprs, childhood, gaf, gender differences, male gender, metaanalysis, nervous-system infection, onset of schizophrenia, onset schizophrenia, risk, s congenital toxoplasmosis, sans, Schizophrenia, serum igg, sex-differences, Toxoplasma gondii

Mental health

Reciprocal moderation by Toxoplasma gondii seropositivity and blood phenylalanine – tyrosine ratio of their associations with trait aggression

October 6, 2016
Mathai, A. J., Lowry, C. A., Cook, T. B., Brenner, L. A., Brundin, L., Groer, M. W., Peng, X. Q., Giegling, I., Hartmann, A. M., Konte, B., Friedl, M. Fuchs, D. Rujescu, D. Postolache, T. T.
Pteridines 2016; 27: 77-85.
Click for abstract
We previously reported that trait aggression, proposed as an endophenotype for suicidal behavior, is positively associated with Toxoplasma gondii (T. gondii) seropositivity in females, but not in males. Additionally, older males seropositive for T. gondii had lower scores on measures of trait aggression, including self-aggression. Trait aggression may be influenced by dopaminergic signaling, which is known to be moderated by gender and age, and potentially enhanced in T. gondii positives through the intrinsic production of dopamine by the microorganism. Therefore, we investigated associations between trait aggression and interactions between T. gondii enzyme-linked immunoabsorbant assay (ELISA) IgG titer-determined seropositivity and high-performance liquid chromatography-(HPLC-) measured blood levels of dopamine precursors phenylalanine (Phe), tyrosine (Tyr), and their ratio in a sample of 1000 psychiatrically healthy participants. Aggressive traits were assessed using the questionnaire for measuring factors of aggression (FAF), the German version of the Buss-Durkee hostility questionnaire. We found that 1) the decrease in trait aggression scores in T. gondii-positive older males was only present in individuals with a low Phe:Tyr ratio, and 2) that there was a positive correlation between Phe: Tyr ratio and total aggression and selected subscales of aggression in T. gondii-positive males, but not in T. gondii-negative males. These findings point toward a gender-specific reciprocal moderation by Phe: Tyr ratio and T. gondii seropositivity of their associations with aggression scores, and lead to experimental interventions geared to manipulating levels of dopamine precursors in selected T. gondii positive individuals with increased propensity for aggression.

Tagged: aggressive personality traits, amino-acids, bipolar disorder, cytokine alterations, depressive symptoms, Dopamine, electroconvulsive-therapy, personality changes, phenylalanine, release, self-directed violence, seropositivity, serum, suicidal-behavior, Toxoplasma gondii, tyrosine

BehaviorPersonality

Infection and characterization of Toxoplasma gondii in human induced neurons from patients with brain disorders and healthy controls

October 3, 2016
Passeri E, Jones-Brando, L Bordon, C Sengupta, S Wilson, AM Primerano, A Rapoport, JL Ishizuka, K Kano, S Yolken, RH Sawa, A
Microbes and Infection 2016; 18: 153-158
Click for abstract
Toxoplasma gondii is a protozoan parasite capable of establishing persistent infection within the brain. Serological studies in humans have linked exposure to Toxoplasma to neuropsychiatric disorders. However, serological studies have not elucidated the related molecular mechanisms within neuronal cells. To address this question, we used human induced neuronal cells derived from peripheral fibroblasts of healthy individuals and patients with genetically-defined brain disorders (i.e. childhood-onset schizophrenia with disease-associated copy number variations). Parasite infection was characterized by differential detection of tachyzoites and tissue cysts in induced neuronal cells. This approach may aid study of molecular mechanisms underlying individual predisposition to Toxoplasma infection linked to neuropathology of brain disorders

Tagged: antibodies, bipolar disorder, brain, cells, conversion, cysts, diseases, disorders, fibroblasts, functional-neurons, induced neuronal cells, risk, Schizophrenia, tachyzoites, Toxoplasma gondii

Physical health

Toxoplasma gondii-A gastrointestinal pathogen associated with human brain diseases

October 3, 2016
Severance, E. G., Xiao, J., Jones-Brando, L., Sabunciyan, S., Li, Y., Pletnikov, M., Prandovszky, E., Yolken, R.
In: Cryan JF, Clarke G, eds. Gut Microbiome and Behavior 2016: pp. 143-163. (International Review of Neurobiology).
Click for abstract
Serious psychiatric disorders such as schizophrenia, bipolar disorder, and major depression are important causes of mortality and morbidity worldwide. While these are primarily diseases involving altered brain functioning, numerous studies have documented increased rates of gastrointestinal inflammation and dysfunction in many individuals with these disorders. Toxoplasma gondii is an apicomplexan protozoan intracellular parasite with a widespread distribution in both developed and developing countries. Toxoplasma organisms enter the ecosystem through the shedding of oocysts by Toxoplasma-infected felines. In almost all cases of postnatal human infection, Toxoplasma enters its hosts through the intestinal tract either by the ingestion of oocysts or by the consumption of meat from food animals which themselves were infected by Toxoplasma oocysts. It had previously been thought that most cases of Toxoplasma infection in immune competent children and adults were inapparent and asymptomatic. However, recent studies cast doubt on this concept as exposure to Toxoplasma has been associated with a range of acute and chronic symptoms. Of particular note has been the finding of an increased rate of a range of neurological and psychiatric disorders associated with serological evidence of Toxoplasma exposure. A role of Toxoplasma infection in brain diseases is also supported by the consistent finding of altered cognition and behavior in animal models of infections. Much of the attention relating to the role of Toxoplasma infection in neuropsychiatric disorders has focused on the brain, where Toxoplasma tissue cysts can persist for extended periods of time. However, recent discoveries relating to the role of the gastrointestinal tract in cognition and behavior suggest that Toxoplasma may also increase susceptibility to human brain diseases through immune activation, particularly involving the gastrointestinal mucosa. The study of the pathways relating to the pathobiology and immunology of Toxoplasma infection may provide insights into the pathogenesis of a range of human neuropsychiatric disorders as well as into cognitive functioning in otherwise healthy individuals.

Tagged: agents, antibodies, bipolar disorder, individuals, infection, inflammatory-bowel-disease, risk factors, Schizophrenia, self-directed violence, united-states

Cognitive functionsMental health

Exposure to perinatal infections and bipolar disorder: A systematic review

May 24, 2016
Barichello, T., Badawy, M., Pitcher, M. R., Saigal, P., Generoso, J. S., Goularte, J. A., Simoes, L. R., Quevedo, J., Carvalho, A. F.
Curr Mol Med 2016; 16: 106-118
Click for abstract
Bipolar disorder (BD) is a debilitating psychiatric disorder and a growing global public health issue. Notwithstanding BD has been conceptualized as a neuroprogressive illness, there are some evidences to suggest a role for neurodevelopmental pathways in the patho-etiology of this disorder. Evidences on the associations between perinatal infections and risk for bipolar disorder have been inconsistent across studies. Here, we performed a systematic review of observational studies on the relationship between exposure to perinatal pathogens and bipolar disorder. A computerized literature search of the PubMed, Embase, and PsyINFO databases till January 31st, 2015 was performed. Twenty-three studies ultimately met inclusion criteria. Studies investigated exposure to several pathogens namely Cytomegalovirus (CMV), Epstein-Barr Virus (EBV), Herpes simplex virus-1 (HSV-1), Herpes simplex virus-2 (HSV-2), Human herpesvirus 6 (HHV-6), Toxoplasma gondii, Influenza, and Varicella zoster virus (VZV). Overall, studies provided mixed evidences. Thus, contrary to schizophrenia, the role of perinatal infections as risk factors for BD remain inconclusive. Larger studies with a prospective design would be necessary to elucidate the role of previous exposure to infectious agents as a potential risk factor for BD.

Tagged: antibodies, bipolar disorder, cerebrospinal fluid, cognitive impairment, cytomegalovirus, herpes, herpes-simplex encephalitis, individuals, influenza, maternal infection, metaanalysis, psychiatric patients, Schizophrenia, systematic review, Toxoplasma gondii, toxoplasma gondii infection

Mental healthReproductionReviews

Mental Health Disorders Associated with Foodborne Pathogens

January 4, 2016
Bolton, D. J., Robertson, L. J.
Journal of Food Protection 2016, 79: 2005-2017
Click for abstract
Human infections with foodborne pathogenic organisms are relatively well described in terms of their overt physical symptoms, such as diarrhea, abdominal cramps, vomiting, fever, and associated sequelae. Indeed, some of these are key for diagnosis and treatment, although it should be noted that, for some foodborne pathogens, the physical symptoms might be more diffuse, particularly those associated with some of the foodborne parasites. In contrast, the impact of these pathogens on mental health is less well described, and symptoms such as depression, anxiety, and general malaise are usually ignored when foodborne infections are recorded. Despite this, it is generally accepted that there are several psychiatric disorders of unknown etiology that may be associated with microbial pathogens. Depression, autism, hypochondriasis and anxiety, schizophrenia, and Tourette syndrome probably have multiple contributing causes, among which foodborne pathogens may play a decisive or contributory role, possibly sharing pathophysiological pathways with other environmental triggers. This review focuses on foodborne parasites and bacterial pathogens. Some foodborne parasites, such as metacestodes of Taenia soliunz and tissue cysts (bradyzoites) of Toxoplasma gondii, may affect mental health by directly infecting the brain. In contrast, bacterial infections and other parasitic infections may contribute to mental illness via the immune system and/or by influencing neurotransmission pathways. Thus, cytokines, for example, have been associated with depression and schizophrenia. However, infectious disease models for psychiatry require a more complete understanding of the relationship between psychiatric disorders and microbial triggers. This article reviews the current state of knowledge on the role of foodborne parasitic and bacterial pathogens in mental illness and identifies some of the gaps that should be addressed to improve diagnosis and treatment of mental health issues that are not solely related to psychiatric factors.

Tagged: autistic spectrum disorders, bacteria, bipolar disorder, chronic-fatigue-syndrome, foodborne pathogens, gastrointestinal symptoms, induced sickness behavior, intestinal microbiota, irritable-bowel-syndrome, maternal exposure, mental health, mood disorders, parasites, toxoplasma gondii infection

Mental health

The correlation between Toxoplasma gondii infection and prenatal depression in pregnant women

January 4, 2016
Shiadeh, M. N., Rostami, A., Pearce, B. D., Gholipourmalekabadi, M., Newport, D. J., Danesh, M., Mehravar, S., Seyyedtabaei, S. J.
European Journal of Clinical Microbiology & Infectious Diseases 2016; 35: 1829-1835
Click for abstract
Previous studies have demonstrated that latent toxoplasmosis is associated with neuropsychiatric disorders. We evaluated the correlation between Toxoplasma gondii infection and prenatal depression. In this case-control study, we enrolled 116 depressed pregnant women and 244 healthy controls. The Edinburgh Postpartum Depression Scale (EPDS) was used to evaluate the depression symptom severity in study participants. All participants were screened for the anti-Toxoplasma IgG by enzyme-linked immunosorbent assay. Seroprevalence of T. gondii did not significantly differ between the depressed pregnant women and healthy controls (OR = 1.4; 95 % CI = 0.9-2.19; P = 0.142). T. gondii IgG titer was significantly higher in depressed women (18.6 +/- 10.9 IUs) than those in the control group (13.6 +/- 8.1 IUs) (z = -5.36, P < 0.001). The T. gondii-positive depressed women showed a positive correlation of T. gondii IgG titer with the EPDS scores (r = 0.52; P < 0.01). The mean EPDS score was also significantly higher in the T. gondii-positive depressed women (20.7 +/- 2.7) compared with the controls (18.36 +/- 2.7) (P < 0.001). The results obtained from the current study revealed that T. gondii infection might affect susceptibility to depression and severity of depressive symptoms in pregnant women, particularly in those patients who have high antibody titers. Further study is required to fully elucidate the characteristics and mechanisms of this association.

Tagged: bipolar disorder, individuals, metaanalysis, mood disorders, personality, postnatal depression, risk factors, sample, Schizophrenia, seropositivity

Mental health

“Latent” infection with Toxoplasma gondii: Association with trait aggression and impulsivity in healthy adults

October 9, 2015
Cook, T. B., Brenner, L. A., Cloninger, C. R., Langenberg, P., Igbide, A., Giegling, I., Hartmann, A. M., Konte, B., Friedl, M., Brundin, L., Groer, M. W., Can, A., Rujescu, D., Postolache, T. T.
Journal of Psychiatric Research 2015; 60: 87-94
Click for abstract
Background: Latent chronic infection with Toxoplasma gondii (T. gondii), a common neurotropic pathogen, has been previously linked with suicidal self-directed violence (SSDV). We sought to determine if latent infection with T gondii is associated with trait aggression and impulsivity, intermediate phenotypes for suicidal behavior, in psychiatrically healthy adults. Methods: Traits of aggression and impulsivity were analyzed in relationship to IgG antibody seropositivity for T gondii and two other latent neurotropic infections, herpes simplex virus 1 (HSV1) and cytomegalovirus (CMV). One thousand community-residing adults residing in the Munich metropolitan area with no Axis I or II conditions by SCID for DSM-IV (510 men, 490 women, mean age 53.6 +/- 15.8, range 20-74). Plasma samples were tested for IgG antibodies to T. gondii, HSV-1 and CMV by ELISA. Self-reported ratings of trait aggression scores (Questionnaire for Measuring Factors of Aggression [FAF]) and trait impulsivity (Sensation-Seeking Scale-V [SSS-V]) were analyzed using linear multivariate methods. Results: T gondii IgG seropositivity was significantly associated with higher trait reactive aggression scores among women (p < .01), but not among men. T. gondii-positivity was also associated with higher impulsive sensation-seeking (SSS-V Disinhibition) among younger men (p < .01) aged 20-59 years old (median age = 60). All associations with HSV-1 and CMV were not significant. Conclusions: Aggression and impulsivity, personality traits considered as endophenotypes for SSDV, are associated with latent T gondii infection in a gender and age-specific manner, and could be further investigated as prognostic and treatment targets in 7: gondii-positive individuals at risk for SSDV.

Tagged: aggression, bipolar disorder, c-reactive protein, impulsivity, indirect hostility, major depressive disorder, midbrain periaqueductal gray, personality, personality-disorders, self-destructive behavior, sensation seeking, suicidal-behavior, Toxoplasma gondii, young adults

Behavior

Treatment with anti-toxoplasmic activity (TATA) for Toxoplasma positive patients with bipolar disorders or schizophrenia: A cross-sectional study

October 9, 2015
Fond, G., Boyer, L., Gaman, A., Laouamri, H., Attiba, D., Richard, J. R., Delavest, M., Houenou, J., Le Corvoisier, P., Charron, D., Krishnamoorthy, R., Oliveira, J., Tamouza, R., Yolken, R., Dickerson, F., Leboyer, M., Hamdani, N.
Journal of Psychiatric Research 2015; 63: 58-64.
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Objective: The association between Toxoplasma gondii seropositivity and respectively Bipolar Disorder (BD) and Schizophrenia/Schizoaffective disorder (SZ) is one of the most studied link between one pathogen and psychiatric disorders. The aim of the present study was thus to retrospectively determine if the administration of an antipsychotic and/or a mood stabilizer having known in vitro Anti-Toxoplasmic Activity (TATA+) was associated with a better clinical outcome in a population of 152 BD or 114 SZ patients and seropositive for T gondii infection compared to patients receiving a treatment without anti-toxoplasmic activity (TATA-). Methods: This multicenter study was conducted in an academic public hospital during a 3-years period between 2009 and 2011. All consecutive inpatients and outpatients with SZ or BD diagnosis with a stable treatment for more than 4 weeks were recruited. socio-demographic and clinical characteristics measured with validated scales as well as a serological status for toxoplasmic infection were included. Treatments were classified according to their in vitro antitoxoplasmic activity. A multivariate model was used to determine the clinical characteristics that were significantly different between patients receiving a treatment with no antitoxoplasmic activity compared to others. Results: BD patients with positive serum antibodies against T gondii presented more lifetime depressive episodes (p = 0.048) after adjustment forage, sex and sociodemographic characteristics when treated by drug having no anti-toxo activity, compared to patients having received drugs with anti-toxo activity. A significant difference was not found in BD toxonegative patients and in SZ toxopositive or toxonegative patients. Conclusions: It seems to be of importance to consider prescribing a drug with a clear anti-toxoplasmic activity (TATA+) for BD patients seropositive to T. gondii, in particular valproate that was found as the mood stabilizer with the highest antitoxoplasmic activity. Prospective randomized controlled trials are warranted to confirm this preliminary data.

Tagged: agents, antipsychotic drugs, bipolar disorder, depression, drugs, gondii infection, individuals, metaanalysis, mood stabilizer, onset, rating-scale, Schizophrenia, suicide attempts, Toxoplasma gondii, validity, valproate

Mental health

Cognitive deterioration among bipolar disorder patients infected by Toxoplasma gondii is correlated to interleukin 6 levels

October 6, 2015
Hamdani, N., Daban-Huard, C., Lajnef, M., Gadel, R., Le Corvoisier, P., Delavest, M., Carde, S., Lepine, J. P., Jamain, S., Houenou, J., Galeh, B., Richard, J. R., Aoki, M., Charron, D., Krishnamoorthy, R., Yolken, R., Dickerson, F., Tamouza, R., Leboyer, M.
Journal of Affective Disorders 2015; 179: 161-166
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Background: Cognitive deficits are present in a large majority of Bipolar Disorder (BD) patients and known to be a marker of bad prognosis. Because, these deficits encompass several domains and no specific medical treatment seems to be effective, it is important to better understand the mechanisms underlying cognitive deterioration. As Toxoplasma gondii is known to induce the synthesis of pro-inflammatory cytokines such as IL-6, we will explore here the possible role of T. gondii in the cognitive decline observed in BD. Methods: 42 euthymic BD patients and 36 controls were assessed for episodic verbal memory using the CVLT and for working memory and verbal ability using the WAIS Ill. Patients and controls were also screened for seropositivity to I gondii and evaluated for the levels of IL-fl transcripts. Results: The seropositivity for I gondii was significantly higher in BD patients as compared to controls (p-0.005). The cognitive deterioration index (Dl) was higher in BD patients (p=5.10 ') and correlated to high IL-6 mRNA expression only among those infected by T gondii (rho-0.43, p-0.01). Among deteriorated patients (defined by scores above 0.10 according to Weschler's definition), the IL-6 mRNA expression was twice greater (p=0.01). Limitations: Our results are to be interpreted with caution because of our small sample size and the cross-sectional design. Conclusions: A long-term exposure to inflammation, measured here with IL-6 mRNA expression in T. gonciii infected BD may alter cognitive functioning. IL-6 could thus be a useful predictive marker of cognitive deterioration in BD and may help to design personalized treatment.

Tagged: antibodies, association, bipolar disorder, cognitive deterioration, exposure, il-6, impairment, individuals, Major depression, risk, Schizophrenia, simplex-virus type-1, t. gondii, traffic accidents

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