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Toxoplasma gondii & Human Phenotype

Compendium of Known Effects and Ongoing Research

gondii

The association between Toxoplasma and the psychosis continuum in a general population setting

September 4, 2018
Lindgren, M., Torniainen-Holm, M., Harkanen, T., Dickerson, F., Yolken, R. H., Suvisaari, J.
Schizophrenia Research 2018; 193: 329-335
Click for abstract
Toxoplasma gondii infection is associated with increased risk for psychosis. However, the possible association between T. gondii and psychotic-like symptoms in the general adult population is unknown. We investigated whether T. gondii is associated with psychotic-like symptoms and psychosis diagnoses using data from Health 2000, a large cross-sectional health survey of the Finnish general population aged 30 and above. Seropositivity to toxoplasma was defined as a cutoff of 50 IU/ml of IgG antibodies. Lifetime psychotic-like symptoms were identified with section G of the Composite International Diagnostic Interview, Munich version (M-CIDI). Symptoms were considered clinically relevant if they caused distress or help-seeking or there were at least three of them. Lifetime psychotic disorders were screened from the sample and were diagnosed with DSM-IV using SCID-I interview and information from medical records. All data were available for 5906 participants. We adjusted for variables related to T. gondii seropositivity (age, gender, education, region of residence, cat ownership, and C-reactive protein measuring inflammation) in regression models. We found that T. gondii seropositivity was significantly associated with clinically relevant psychotic-like symptoms (OR 1.77, p = 0.001) and with the number of psychotic-like symptoms (IRR = 1.55, p = 0.001). The association between toxoplasma and diagnosed psychotic disorders did not reach statistical significance (OR 1.45 for schizophrenia). In a large sample representing the whole Finnish adult population, we found that serological evidence of toxoplasma infection predicted psychotic-like symptoms, independent of demographic factors and levels of C-reactive protein. Toxoplasma infection may be a risk factor for manifestation of psychotic-like symptoms.

Tagged: antibodies, c-reactive protein, diseases, disorders, gondii, high-risk, individuals, infectious agents, metaanalysis, population, psychotic disorder, psychotic-like symptom, Schizophrenia, Toxoplasma gondii

Mental health

Toxoplasmosis, but not borreliosis, is associated with psychiatric disorders and symptoms

August 31, 2018

Schizophrenia Research 2018; 197: 603-604
Tagged: autism, etiology, gondii, incidence, infection hypothesis, Major depression, ocd, risk factors, Schizophrenia

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

Chronic Toxoplasma gondii infection induces anti-N-methyl-D-aspartate receptor autoantibodies and associated behavioral changes and neuropathology

February 12, 2018
Li, Y, Viscidi, R. P., Kannan, G., McFarland,R., Pletnikov, M. V., Severance,E. G., Yolken, R. H., Xiao, J. C.
Infection and Immunity 2018; 86: DOI: 10.1128/iai.00398-18
Click for abstract
Anti-NMDA receptor (NMDAR) autoantibodies have been postulated to play a role in the pathogenesis of NMDAR hypofunction, which contributes to the etiology of psychotic symptoms. Toxoplasma gondii is a pathogen implicated in psychiatric disorders and associated with elevation of NMDAR autoantibodies. However, it remains unclear whether parasite infection is the cause of NMDAR autoantibodies. By using mouse models, we found that NMDAR autoantibody generation had a strong temporal association with tissue cyst formation, as determined by MAGI antibody seroreactivity (r = 0.96; P < 0.0001), which is a serologic marker for the cyst burden. The presence of MAGI antibody response, but not T. gondii IgG response, was required for NMDAR autoantibody production. The pathogenic relevance of NMDAR autoantibodies to behavioral abnormalities (blunted response to amphetamine-triggered activity and decreased locomotor activity and exploration) and reduced expression of synaptic proteins (the GLUN2B subtype of NMDAR and PSD-95) has been demonstrated in infected mice. Our study suggests that NMDAR autoantibodies are specifically induced by persistent T. gondii infection and are most likely triggered by tissue cysts. NMDAR autoantibody seroreactivity may be a novel pathological hallmark of chronic toxoplasmosis, which raises questions about NMDAR hypofunction and neurodegeneration in the infected brain.

Tagged: Amphetamine, antibodies, autoantibody, behavioral abnormalities, chronic infection, Dopamine, encephalitis, expression, gondii, hos, immune-response, MAGI antibody, mice, neuropathology, nmda receptor, tissue cyst, Toxoplasma gondii

BehaviorMental 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

Toxoplasmosis, but not borreliosis, is associated with psychiatric disorders and symptoms MENTAL

February 12, 2018
Flegr, J., Horáček, J.
Schizophrenia Research 2018; 197: 603-604
Tagged: autism, etiology, gondii, infection hypothesis, Major depression, ncidence, ocd, risk factors, Schizophrenia

Mental health

Impact of ApoE genotypes variations on Toxoplasma patients with dementia

December 8, 2017
Yahya, R. S., Awad, S. I., El-Baz, H. A., Saudy,N., Abdelsalam, O. A., Al-Din, M. S. S.
Journal of Clinical Neuroscience 2017;39:184-188
Click for abstract
Background: Toxoplasma deprives host neuron cells from cholesterol and leads to its ability to potentiate dementia. ApoE intermediates neuronal transmission of cholesterol, which is a key constituent for axonal development, redesigning occasions that are important for education and synaptic arrangement, development of memory and repair of neuron. The aim of this work is to investigate the effect of ApoE genotypes on dementia associated with neurodegeneration in latent Toxoplasma gondii in elderly population. Methods: This study comprised: 133 patients with dementia (78 were positive for toxoplasma IgG and 55 were negative) and 95 subjects as control group without dementia (30 were positive for toxoplasma IgG and 65 were negative). All of them were subjected to a cognitive assessment, T. gondii seropositivity (ELISA) and determination of ApoE allelic forms (PCR). Results: The ApoE genotype distribution shows that the most predominant genotype is ApoE3/3 and the most widely recognized allele is E3. Both patients and control were further divided into Toxoplasma IgG positive group (n = 108) and Toxoplasma IgG negative group (n = 120). ApoE4 non carrier, ApoE 2/3 and ApoE 3/3 alleles have highly significant differences (P < 0.001) between dementia and non-dementia patients in Toxoplasma infected patients in comparison to non-infected ones. Conclusion: Toxoplasma positive patients have more risk to develop dementia regardless ApoE4 carriage. (C) 2017 Elsevier Ltd. All rights reserved.

Tagged: alzheimers-disease, apoE, apolipoprotein-e, association, brain, cells, dementia, gondii, neurocognitive dysfunctions, Toxoplasma

Mental health

A critical assessment of the association between postnatal toxoplasmosis and epilepsy in immune-competent patients

December 8, 2017
Uzorka, J. W., Arend, S. M.
European Journal of Clinical Microbiology and Infectious Diseases 2017; 7:1111-1117
Tagged: africa, cryptogenic epilepsy, gondii, infection, toxocara, united-states

Mental health

Significance of chronic toxoplasmosis in epidemiology of road traffic accidents in Russian Federation

December 8, 2017
Stepanova, E. V., Kondrashin, A. V., Sergiev, V. P., Morozova, L. F., Turbabina, N. A., Maksimova, M. S., Brazhnikov, A. I., Shevchenko, S. B., Morozov, E. N.
PLoS ONE 2017;12: 10.1371/journal.pone.0184930
Click for abstract
Studies carried out in Moscow residents have revealed that the prevalence of chronic toxoplasmosis is very close to those in countries of Eastern and Central Europe. Our findings also demonstrated a statistically significant relationship between the rate of traffic accidents and the seroprevalence of chronic toxoplasmosis in drivers who were held responsible for accidents. The latter was 2.37 times higher in drivers who were involved in road accidents compared with control groups. These results suggest that the consequences of chronic toxoplasmosis (particularly a slower reaction time and decreased concentration) might contribute to the peculiarities of the epidemiology of road traffic accidents in the Russian Federation and might interfere with the successful implementation of the Federal Programme named "Increase road traffic safety" . Suggestions for how to address overcome this problem are discussed in this paper.

Tagged: behavior, gondii, human personality, humans, latent toxoplasmosis, Parasite, risk

Behavior

Prenatal toxoplasmosis antibody and childhood autism

October 2, 2017
Spann, M. N., Sourander, A., Surcel, H. M., Hinkka-Yli-Salomaki, S., Brown, A. S.
Autism Research 2017; 10: 769-777
Click for abstract
here is evidence that some maternal infections during the prenatal period are associated with neurodevelopmental disorders, such as childhood autism. However, the association between autism and Toxoplasma gondii (T. gondii), an intracellular parasite, remains unclear. The authors examined whether serologically confirmed maternal antibodies to T. gondii are associated with odds of childhood autism in offspring. The study is based on a nested case-control design of a large national birth cohort (N=1.2 million) and the national psychiatric registries in Finland. There were 874 cases of childhood autism and controls matched 1: 1 on date of birth, sex, birthplace and residence in Finland. Maternal sera were prospectively assayed from a national biobank for T. gondii IgM and IgG antibodies; IgG avidity analyses were also performed. High maternal T. gondii IgM antibody was associated with a significantly decreased odds of childhood autism. Low maternal T. gondii IgG antibody was associated with increased offspring odds of autism. In women with high T. gondii IgM antibodies, the IgG avidity was high for both cases and controls, with the exception of three controls. The findings suggest that the relationship between maternal T. gondii antibodies and odds of childhood autism may be related to the immune response to this pathogen or the overall activation of the immune system.

Tagged: antibody, autism, avidity, c-reactive protein, childhood, congenital toxoplasmosis, gondii, igg, infection, latent toxoplasmosis, rheumatoid-arthritis, risk, spectrum disorder, toxoplasmosis

Mental health

Toxoplasmosis, leptospirosis, and brucellosis seroepidemiology in veterinary medical students and their relation with unique health

January 4, 2017
Clazer, M., Rodrigues, G. V., Ferreira, B. P. M., Zaniolo, M. M., Correa, N. A. B., Fortes, M. S., Navarro, I. T., Chiderolli, R. T., de Freitas, J. C., Goncalves, D. D.
Semina-Ciencias Agrarias, 2017, 38: 1347-1359
Click for abstract
Toxoplasmosis, leptospirosis, and brucellosis are global zoonoses, with humans as accidental participants in their transmission cycles. The can also be considered occupational diseases, because certain professionals are at greater risk of contact and infection by such zoonoses. These three diseases have different epidemiological characteristics because of the distinct environmental, social, cultural, and economic conditions where these pathogens circulate. Because of the importance of these diseases and their associations with specific occupations, we performed a seroepidemiological survey of Toxoplasma, Leptospira, and Brucella antibodies, with an analysis of the association between positive serum and certain occupational and environmental variables, in students of a veterinary medicine course (1st, 2nd, 3rd, 4th, and 5th year) in a university in the northwestern region in the state of Parana, Brazil. From May to November 2014, blood samples were collected from 157 volunteers by professionals trained in nursing and biomedicine from the same university as the veterinary students. At the time of blood collection, the students did not present any clinical signs of the three diseases of interest. To detect anti-Toxoplasma gondii, anti-Leptospira spp., and anti-Brucella antibodies, indirect immunofluorescence test (IIF), microscopic agglutination test (MAT), fast agglutination test (a screening test), and enzyme-linked immunosorbent assay (ELISA) were performed. To determine variables associated with these infections, the students were interviewed to complete an epidemiological questionnaire with environmental, behavioral, and occupational information. The associations between these variables and infections were assess by chi-square or Fischer's exact tests, with a 5% significance level (a). Of the 157 serum samples analyzed, 29.29% reacted to Toxoplasma antigens, with titers ranging from 16 to 4096 by IIF, 1.27% to Leptospira antigens, with titers ranging from 100 to 800 by MAT using Hardjo and Wolffi serovars, and 0.63% to Brucella antigens by ELISA; however, no variables were found to be associated with infection with any of these pathogens. The results of this study show that one-third of the students in the veterinary medicine course were exposed to Toxoplasma gondii, Leptospira spp., and Brucella spp. at some stage in their lives; however, it is not possible to determine whether these infections were acquired at the university, because no associations between occupational risk variables and these infections were found. An understanding of the transmission of each etiological agent and methods to prevent infection is important to maintain low prevalence levels of these zoonotic diseases during the veterinary medicine course and extra-curricular internships, when there is increased exposure to these pathogens.

Tagged: animals, antibodies, bovine brucellosis, brazil, brucella spp., gondii, high prevalence, humans, infection, leptospira spp., occupational disease, parana, state, Toxoplasma gondii, Zoonosis

Physical health

Schizophrenia and infections: The eyes have it

January 3, 2017
Torrey, E. F. ,Yolken, R. H.
Schizophrenia Bulletin 2017; 43: 247-252
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The visual tract is prominently involved in schizophrenia, as evidenced by perceptual distortions and a type of nystagmus found in many individuals affected. Genetic explanations for these abnormalities have been suggested. This study proposes an alternate explanation based on infection. Several infectious agents thought to be associated with some cases of schizophrenia are known to cause both infection of the fetus and abnormalities of the eye. Toxoplasma gondii is examined in detail, and rubella, cytomegalovirus, varicellazoster virus, and herpes simplex virus more briefly. Careful ophthalmic assessments, including funduscopy and direct examination of tissues for infectious agents, will clarify the role of such agents in ocular aspects of schizophrenia.

Tagged: adult schizophrenia, cat ownership, congenital toxoplasmosis, gondii, herpes-simplex-virus, infections, movement abnormalities, ocular, ocular toxoplasmosis, psychosis, risk factors, Schizophrenia, smooth-pursuit, toxoplasmosis

Mental health

No association between latent toxoplasmosis and multiple body measures in US adults

October 6, 2016
Berrett, A. N., Gale, S. D., Erickson, L. D., Brown, B. L., Hedges, D. W.
Folia Parasitologica 2016; 63: 034, 10.14411/Fp.2016.034
Click for abstract
Toxoplasma gondii (Nicolle et Manceaux, 1908) is an intracellular parasite that can cause ongoing latent infection persisting for the duration of a non-definitive host's life. Affecting approximately one-third of the world's population, latent toxoplasmosis has been associated with neuropsychological outcomes and a previous report suggested an association between latent toxoplasmosis and adult height. Given the large number of people with latent toxoplasmosis and its potential associations with human height, we sought to better understand the association between latent toxoplasmosis and human morphology by evaluating seropositivity for T. gondii and multiple body measures reported in the National Health and Nutrition Examination Survey III (NHANES III) and in the more recent continuous NHANES data sets from the United States Centers for Disease Control and Prevention for which data on T. gondii are available. In these analyses, latent toxoplasmosis was not associated with any of the body measures assessed in the NHANES datasets even after taking into account interactions between latent toxoplasmosis and testosterone suggesting that in these samples, latent toxoplasmosis is not associated with adult morphology including height.

Tagged: bmi, gondii, height, seroprevalence, testosterone, Toxoplasma gondii, united-states

Morphology

No association between current depression and latent toxoplasmosis in adults

October 6, 2016
Gale, S. D., Berrett, A. N., Brown, B., Erickson, L. D., Hedges, D. W.
Folia Parasitologica 2016; 63: DOI 10.14411/fp.2016.032
Click for abstract
Changes in behaviour and cognition have been associated with latent infection from the apicomplexan protozoan Toxoplasma gondii (Nicolle et Manceaux, 1908) in both animal and human studies. Further, neuropsychiatric disorders such as schizophrenia have also been associated with latent toxoplasmosis. Previously, we found no association between T. gondii immunoglobulin G antibody (IgG) seropositivity and depression in human adults between the ages of 20 and 39 years (n = 1 846) in a sample representative of the United States collected by the Centers for Disease Control as part of a National Health and Nutrition Examination Survey (NHANES) from three datasets collected between 1999-2004. In the present study, we used NHANES data collected between 2009 and 2012 that included subjects aged 20 to 80 years (n = 5 487) and used the Patient Health Questionnaire 9 (PHQ-9) to assess depression with the overall aim of testing the stability of the results of the prior study. In the current study, the seroprevalence of T. gondii was 13%. The percentage of subjects reporting clinical levels of depression assessed with the PHQ-9 was 8%. As before, we found no association between T. gondii IgG seroprevalence and depression (OR = 1.01, 95% CI = 0.81-1.25; p = 0.944) while controlling for sex, educational attainment, race-ethnicity, age, poverty-to-income ratio and cigarette smoking. We also found no positive associations between anti-T. gondii antibody titre and depression (OR = 1.00, 95% CI = 0.96-1.06; p = 0.868). Moreover, we found no association between T. gondii seroprevalence or antibody titre and suicidal ideation (seroprevalence: OR = 1.22, 95% CI =.85-1.75; p = 0.277, titre: OR = 1.05, 95% CI = 0.98-1.14; p = 0.177). Defining depression to also include subjects currently taking antidepressant medication even with non-elevated questionnaires did not find evidence of a positive association between latent toxoplasmosis and depression. In the present study, neither T. gondii seroprevalence nor anti-T. gondii antibody titre was positively associated with depression or suicidal ideation among subjects aged 20 to 80 years.

Tagged: antibody-titers, gondii, history, infection, major depressive disorder, metaanalysis, mood disorders, nhanes, Schizophrenia, suicide attempts, Toxoplasma gondii, women

Mental health

Assessment of Toxoplasma sweropositivity in children suffering from attention deficit hyperactivity disorder

January 4, 2016
Afsharpaiman, S., Khosravi, M. H., Faridchehr, M., Komijani, M., Radfar, S., Amirsalari, S., Torkaman, M., Shirbazoo, S.
Galen Medical Journal 2016; 5: 188-193
Click for abstract
Background: Toxoplasmosis, a protozoan infection caused by Toxoplasma gondii, is suggested to be a risk factor for many psychological disorders such as schizophrenia and depression. Attention deficit hyperactivity disorder (ADHD) is one of the most common psychiatric disorders among children. Previous studies have assessed the correlation between ADHD and infectious diseases like toxoplasmosis. So we aimed to investigate the possible correlation between Toxoplasma seropositivity and ADHD in children. Materials and Methods: In this cross-sectional study children with signs of ADHD were regarded as patients and underwent clinical assessments. Diagnosis of these patients was based on DSM-IV-TR system which was performed by a pediatric psychiatrist. Forty-eight Children without signs of ADHD or other psychic disorders were considered as control, and 48 patients were considered as case group. Parents were asked to answer a questionnaire including demographic, pregnancy and habitual questions. Blood samples were taken from all individuals and assessed for anti-Toxoplasma IgM and IgG antibodies. Results: Ninety-six male and female patients with a mean age of 8.12 years underwent analysis. Seropositivity rate for anti-T.gondii IgG antibody was 4.2% in the case and 2.1% in control individuals (P=0.92). Anti-T.gondii IgM antibodies were not found in control individuals while it was found in 2.1% of case individuals (P=0.74). There was no statistically significant association between seroprevalence of IgM (P=0.74) and IgG (P=0.92) antibodies and ADHD in study individuals. Conclusion: Our findings showed that the toxoplasmosis seropositivity has no significant difference between children with and without ADHD. Further studies are needed with a larger amount of individuals.

Tagged: antibodies, attention deficit hyperactivity disorder, children, gondii, metaanalysis, population, risk factors, Schizophrenia, Toxoplasma gondii, toxoplasmosis

Mental health

Is there any role of latent toxoplasmosis in schizophrenia disease?

October 6, 2015
Karabulut, N., Bilgic, S., Gurok, M. G., Karaboga, F.
Journal of the Chinese Medical Association 2015; 78: 533-537
Click for abstract
Background: A large number of studies have hypothesized that Toxoplasma gondii is a potentially relevant etiological factor in some cases of schizophrenia. By contrast, some studies have disproved this association. The aim of this study was to investigate whether latent toxoplasmosis has any role in schizophrenia disease. Additionally, the association between T. gondii and subtypes of schizophrenia, and the impacts of toxoplasmosis on psychopathology were examined in the study. Methods: A total of 85 patients with schizophrenia and 60 healthy volunteers were included in this prospective study. Immunoglobulin G (IgG) antibody to T. gondii was examined by enzyme-linked immune-sorbent assay method. Results: Seropositivity rates were 43.5% for the patients with schizophrenia and 43.3% for the healthy controls (odds ratio: 1.008, 95% confidence interval: 0.517-1.964, p = 0.981). There was no significant difference in T gondii IgG positivity between the schizophrenia and control groups with respect to sex and age. The difference in seroprevalence of T gondii IgG antibodies among the schizophrenia subtypes was not statistically significant (p = 0.934). No significant difference was found in Positive and Negative Syndrome Subscales between Toxoplasma-infected and Toxoplasma-free patients. Conclusion: In the study area with a high prevalence of T gondii, no association between toxoplasmosis and schizophrenia was detected. These findings showed that toxoplasmosis has no role in the risk of schizophrenia disease.

Tagged: antibodies, gondii, Schizophrenia, Toxoplasma gondii, toxoplasmosis

Mental health

Toxoplasmosis: A threat to mothers and babies, but one that is preventable

May 28, 2015
Moore, S. C.
International Journal of Childbirth Education 2015; 30: 35-38
Click for abstract
The purpose of this article is to review definition, epidemiology, and pathophysiology of toxoplasmosis. Congenital toxoplasmosis is the focus because of its potential adverse effects on children. Transmission to fetus and diagnosis during pregnancy are discussed. Timing of prenatal as well as post-delivery treatment are summarized. Latent effects and additional diseases thought to be associated with toxoplasmosis are reviewed. Primary prevention is emphasized such as avoiding undercooked meat and contaminated fruits/vegetables; consuming only safe drinking water; and eliminating exposure to contaminated cat litter (dried feces) or soil. Secondary and tertiary prevention are addressed.

Tagged: congenital, gondii, infection, pregnancy, prevention, Schizophrenia, Toxoplasma gondii, toxoplasmosis

Mental healthReproduction

The influence of latent toxoplasmosis on women’s reproductive function: four cross-sectional studies

January 8, 2015
Kankova, S., Flegr, J., Calda, P.
Folia Parasitologica 2015; 62:
Click for abstract
Several studies have investigated the association between infection with Toxoplasma gondii (Nicolle et Manceaux, 1908), pregnancy and fertility, but the results of studies focused on the fertility are rather ambiguous. Here we report results of four new cross-sectional studies. The studies were performed in the General University Hospital, Prague (study A with n = 1 165, and study C with n = 317), in private clinics of the Centre of Reproductive Medicine, Prague (study B with n = 1 016), and in a population of Czech and Slovak volunteers from the Facebook page 'Guinea Pigs' willing to participate in various basic science studies (study D with n = 524). In studies A and B, the clinical records were used to assess the fertility problems, whereas in studies C and D, the women were asked to rate their fertility problems using a six-point scale. Pregnant T. gondii-infected women were older than T. gondii-free women (study A: 33.1 vs 31.2, P < 0.001; study B: 30.6 vs 29.6, P = 0.012) and more often used assisted reproductive technology to conceive (study A: 17.2% vs 12.4%, P = 0.041; study B: 13.4% vs 9.2%, P = 0.317). Pregnant T. gondii-infected primiparous women were older than T. gondii-free primiparas (study A: 31.1 vs 29.5, P < 0.001; study B: 29.7 vs 28.9, P = 0.064) and more often used assisted reproductive technology to conceive (study A: 24.7% vs 14.4%, P = 0.010; study B: 15.9% vs 15.5%, P = 0.888). T. gondii-infected women reported to take a longer time to conceive than T. gondii-free women (P = 0.015). They also claimed to have more fertility problems than T. gondii-free women (P < 0.0001). Our results suggest that 'asymptomatic' latent toxoplasmosis could be a more serious source of fertility problems and health-associated burden than more severe but far rarer congenital toxoplasmosis.

Tagged: age, asymptomatic toxoplasmosis, behavioral-changes, gender differences, gondii, hypothesis, infertility, manipulation hypothesis, mice, Parasite, psychiatric-disorders, Schizophrenia, sex ratio, testosterone, Toxoplasma gondii

Reproduction

Psychiatric disorders in Toxoplasma seropositive patients – CD8 connection

October 11, 2013
Bhadra, R., Cobb, D. A., Weiss, L. M., Khan, I. A.
Schizophrenia Bulletin 2013; 39: 485-489
Click for abstract
Although the highest numbers of studies linking an infectious agent with schizophrenia has involved the parasite Toxoplasma gondii, the mechanistic underpinnings of this correlation has remained unaddressed. Incidentally, CD8 T cells, which play a pivotal role in mediating long-term immunity to Toxoplasma, are downregulated in schizophrenia patients. Recent studies have demonstrated that CD8 response is also impaired during chronic toxoplasmosis in murine models. In light of these new findings, in this article, we discuss the potential role of CD8 T cells in causing altered mental status in Toxoplasma seropositive schizophrenia patients.

Tagged: behavior, cd8 t cells, cells, disease, Dopamine, exhaustion, gondii, infection, lymphocytes, oxoplasma, pd-1, receptors, risk factors, Schizophrenia

Mental health

Rhesus factor modulation of effects of smoking and age on psychomotor performance, intelligence, personality profile, and health in Czech soldiers

January 9, 2012
Flegr, J., Geryk, J., Volny, J., Klose, J., Cernochova, D.
Plos One 2012; 7: ARTN e49478 10.1371/journal.pone.0049478
Click for abstract
Background: Rhesus-positive and rhesus-negative persons differ in the presence-absence of highly immunogenic RhD protein on the erythrocyte membrane. This protein is a component of NH3 or CO2 pump whose physiological role is unknown. Several recent studies have shown that RhD positivity protects against effects of latent toxoplasmosis on motor performance and personality. It is not known, however, whether the RhD phenotype modifies exclusively the response of the body to toxoplasmosis or whether it also influences effects of other factors. Methodology/Principal Findings: In the present cohort study, we searched for the effects of age and smoking on performance, intelligence, personality and self-estimated health and wellness in about 3800 draftees. We found that the positive effect of age on performance and intelligence was stronger in RhD-positive soldiers, while the negative effect of smoking on performance and intelligence was of similar size regardless of the RhD phenotype. The effect of age on four Cattell's personality factors, i.e., dominance (E), radicalism (Q(1)), self-sentiment integration (Q(3)), and ergic tension (Q(4)), and on Cloninger's factor reward dependency (RD) was stronger for RhD-negative than RhD-positive subjects, while the effect of smoking on the number of viral and bacterial diseases was about three times stronger for RhD-negative than RhD-positive subjects. Conclusions: RhD phenotype modulates the influence not only of latent toxoplasmosis, but also of at least two other potentially detrimental factors, age and smoking, on human behavior and physiology. The negative effect of smoking on health (estimated on the basis of the self-rated number of common viral and bacterial diseases in the past year) was much stronger in RhD-negative than RhD-positive subjects. It is critically needed to confirm the differences in health response to smoking between RhD-positive and RhD-negative subjects by objective medical examination in future studies.

Tagged: abilities, cigarette-smoke, gondii, humans, latent toxoplasmosis, men, parasite toxoplasma, rh, risk, women

BehaviorCognitive functionsMotor functionsPersonality

Potential immunomodulatory effects of latent toxoplasmosis in humans

January 9, 2011
Flegr, J., Striz, I.
Bmc Infectious Diseases 2011; 11: Artn 274 10.1186/1471-2334-11-274
Click for abstract
Background: About 30% of the population worldwide are infected with the protozoan parasite Toxoplasma gondii. Latent toxoplasmosis has many specific behavioral and physiological effects on the human organism. Modified reactivity of the immune system has been suggested to play a key role in many of these effects. For example, the immunosuppression hypothesis explains the higher probability of the birth of male offspring observed in Toxoplasma-positive humans and mice by the protection of the (more immunogenic) male embryos against abortion. Methods: Here we searched for indices of immunosuppression in Toxoplasma-positive subjects by comparing clinical records of immunology outpatients. Results: Our cohort study showed that the male patients with latent toxoplasmosis had decreased and the Toxoplasma-positive women had increased leukocyte, NK-cell and monocyte counts in comparison with controls. The B-cell counts were reduced in both Toxoplasma-positive men and women. The difference between Toxoplasma-positive and Toxoplasma-negative subjects diminished with the decline of the specific Toxoplasma antibody titre (a proxy for the length of infection), which is consistent with the observed decreasing strength of the effect of latent toxoplasmosis on human reproduction. The prevalence of toxoplasmosis in 128 male patients was unusually low (10.9%) which contrasted with normal prevalence in 312 female patients (23.7%) and in general population Prague (20-30%). Conclusions: Latent toxoplasmosis has immunomodulatory effects in human and probably protects men against some classes of immunopathological diseases. The main limitation of the present study was the absence of the data on the immunoreactivity of immune cells subpopulations. Therefore further studies are needed to search for indices of immunosuppression in human using more specific markers.

Tagged: antibodies, behavioral-changes, communication, gender differences, gondii, hypothesis, mice, sex ratio, testosterone concentration, traffic accidents

Physical health

Autism spectrum disorders may be due to cerebral toxoplasmosis associated with chronic neuroinflammation causing persistent hypercytokinemia that resulted in an increased lipid peroxidation, oxidative stress, and depressed metabolism of endogenous and exogenous substances

October 19, 2010
Prandota J.
Research in Autism Spectrum Disorders 2010; 4: 119-155
Click for abstract
Worldwide, approximately 2 billion people are chronically infected with Toxoplasma gondii with largely yet unknown consequences. Patients with autism spectrum disorders (ASD) similarly as mice with chronic toxoplasmosis have persistent neuroinflammation, hypercytokinemia with hypermetabolism associated with enhanced lipid peroxidation, and extreme changes in the weight resulting in obesity or wasting. Data presented in this review suggest that environmental triggering factors such as pregnancy, viral/bacterial infections, vaccinations, medications, and other substances caused reactivation of latent cerebral toxoplasmosis because of changes in intensity of latent central nervous system T. gondii infection/inflammation and finally resulted in development of ASD. Examples of such environmental factors together with their respective biomarker abnormalities are: pregnancy (increased NO, IL-1 beta, TNF-alpha, IL-6, IL-10, prolactin: decreased IFN-gamma, IL-12), neuroborreliosis (increased IL-1 beta, sIL-1R2, TNF-alpha, IFN-gamma, IL-6, IL-10, IL-12, IL-18, transforming growth factor-beta 1 (TGF-beta 1)), vital infections (increased IL-1 beta, IL-6, IL-8, TNF-alpha, IFN-gamma/alpha/beta,TGF-beta 1), thimerosal (increased IL-5, IL-13; decreased IFN-gamma,TNF-alpha,IL-6, IL-12p70, NOS), and valproic acid (increased NO, reactive oxygen species; decreased TNF-alpha, IL-6, IFN-gamma). The imbalances in pro- and antiinflammatory processes could markedly hinder [lost defense mechanisms important for immune control of the parasite, such as the production of NO, cytokines, and reactive oxygen/nitrogen species, tryptophan degradation by indoleamine 2,3-dioxygenase and/or tryptophan 2,3-dioxygenase, limitation of the availability of intracellular iron to T gondii, and the mechanisms mediated by an IFN-gamma responsive gene family. These fluctuations could result in a recurrent profuse multiplication of T. gondii in the brain associated with persistent neuroinflammation, chronic overproduction of pro- and antiinflammatory cytokines, and NO causing increased oxidative stress, and significantly depressed activity of several enzymes including cytochrome P450 monooxygenase family responsible for metabolism of physiological substrates and xenobiotics, such as steroids, fatty acids, prostaglandins, drugs, pollutants, and carcinogens, finally leading to development of ASD. This reasoning may be supported by such abnormal metabolic events as: (1) patients with ASD have significantly decreased melatonin levels caused by marked deficit in acetylserotonin methyltransferase activity, possibly resulting from maternal and/or fetal/postnatal overproduction of NO, characteristic for this clinical entity; (2) thimerosal inhibited both insulin-like growth factor-1- and dopamine-stimulated methylation reactions, and depressed methionine synthase activity, the metabolic events important for promoting normal neurodevelopment; (3) valproic acid, a strong histone deacetylase inhibitor, have potent anti-T. gondii activity. Thus, patients with ASD should be tested for T. gondii infection. (C) 2009 Elsevier Ltd. All rights reserved

Tagged: abnormalities, abnormality, acid, acids, aktivity, autism, autistic spectrum disorders, availability, beta, biomarker, brain, cell-mediated-immunity, central-nervous-system, cerebral, Cerebral toxoplasmosis, change, changes, chronic, chronic neuroinflammation, chronic toxoplasmosis, clinical, congenital cytomegalovirus-infection, consequence, consequences, control, could, cytochrome, cytochrome p450, cytokine, cytokines, data, defense, defense-mechanisms, deficit, degradation, depressed enzyme activities, development, disorder, disorders, drug, drugs, environmental, environmental factors, enzyme, enzymes, event, events, example, families, family, fluctuation, fluctuations, gene, gene families, gene family, gondii, gondii infection, growth, growth-factor-beta, hepatic drug-metabolism, herpes-simplex-virus, histone, histone deacetylase, hypercytokinemia, hypermetabolic state, il-1, il-10, il-12, il-13, il-6, immune, immune irregularities, important, infection, infections, inhibitor, insulin-like, intensity, interferon-inducing agents, intracellular, iron, latent, level, limitation, lipid, lipid-peroxidation, maternal, mechanism, mechanisms, medication, melatonin, metabolism, methionine, methylation, methyltransferase, methyltransferase aktivity, mice, multiplication, nervous, nervous system, neurodevelopment, nf-kappa-b, nitric oxide, nitric-oxide synthase, obesity, or, overproduction, oxidative stress, oxygen, p-450-dependent monooxygenase systems, Parasite, patient, patients, people, persistent, pregnancies, pregnancy, proces, prolactin, prostaglandins, reaction, reactivation, review, species, spectrum, spectrum disorders, spektra, steroids, stress, substrate, systém, t, tgf-beta, tnf-alpha, Toxoplasma, Toxoplasma gondii, toxoplasmosis, tryptophan, tumor-necrosis-factor, vaccination, vital, weight, xenobiotics

Mental health

Possible role of toxoplasmosis in patients with first-episode schizophrenia

October 19, 2010
Tanyuksel, M., Uzun, O., Araz, E., Koru, O., Babur, C.
Turkish Journal of Medical Sciences 2010; 40: 399-404
Click for abstract
Aim: To determine the possible relationship between toxoplasmosis and patients with first-episode schizophrenia (FES) Materials and methods: Seventy-three subjects with FES (15-54 years old; mean. 23.4 years) and 40 healthy individuals (20-54 years old, mean: 30.3 years) were enrolled in the study Most of the FES patients (90.4%) and the control individuals (95 0%) were male Specific IgG and IgM antibodies to Toxoplasma gondii were investigated by enzyme-linked immunosorbent assay (ELISA), and the total amount of antibodies was investigated with the Sabin-Feldman dye test (SFDT) Results: Compared to the control individuals, study subjects had significantly more toxoplasmosis-like symptoms and more cats in the household; they were less likely to live in apartments and more likely to live in ground-floor houses They did consume more uncooked meat, unpasteurized goat's milk, and chicken eggs; had more contact with soil; and were living less often in urban areas and more often in rural areas. Serum samples from 32 (43 8%) and 25 (34.2%) of 73 patients with FES were seropositive for T gondii when tested by ELISA IgG and SFDT, respectively Out of 40 serum samples from control subjects, 13 (32 5%) and 15 (37.5%) were found positive for T gondii by ELISA IgG and SFDT, respectively In patients with FES, 17 (68%) out of 25 who were SFDT-positive were also positive by ELISA IgG test, while 15 out of 48 (31 3%) SFDT-negative serums were positive by ELISA IgG In the control group, 11 out of 15 SFDT-positive serum samples (73 3%) were also positive by ELISA IgG test, while 2 out of 25 SFDT-negative serum samples were positive by ELISA IgG Conclusion: The present study shows that toxoplasmosis might be associated with first-episode schizophrenia. More studies are needed to prove the association between T gondii infection and patients suffering from schizophrenia

Tagged: antibodies, antibody, area, assay, cat, cats, chicken, contact, control, egg, eggs, elisae, enzyme-linked immunosorbent assay, Fe, gondii, gondii infection, group, house, igg, igm, IgM antibodies, individual, individuals, infection, Ireland, male, meat, method, methods, milk, old, patient, patients, positive, psychosis, relationship, Sabin Feldman dye test sample, samples, Schizophrenia, sera, serum, serum sample, soil, symptoms, t test, Toxoplasma gondii, toxoplasmosis, year

Mental health

Modulation of immunity in mice with latent toxoplasmosis-the experimental support for the immunosuppression hypothesis of Toxoplasma-induced changes in reproduction of mice and humans

January 8, 2010
Kankova, S., Holan, V., Zajicova, A., Kodym, P., Flegr, J.
Parasitology Research 2010; 107: 1421-1427
Click for abstract
The immunosuppression hypothesis suggests that the increased sex ratio in mice and women with latent toxoplasmosis, retarded embryonic growth in the early phases of pregnancy, prolonged pregnancy of Toxoplasma-infected women, and increased prevalence of toxoplasmosis in mothers of children with Down syndrome can be explained by the presumed immunosuppressive effects of latent toxoplasmosis. Here, we searched for indices of immunosuppression in mice experimentally infected with Toxoplasma gondii. Our results showed that mice in the early phase of latent infection exhibited temporarily increased production of interleukin (IL)-12 and decreased production of IL-10. In accordance with the immunosuppression hypothesis, the mice showed decreased production of IL-2 and nitric oxide and decreased proliferation reaction (synthesis of DNA) in the mixed lymphocyte culture in the early and also in the late phases of latent toxoplasmosis. Since about 30% of the world population are latently infected by T. gondii, the toxoplasmosis-associated immunosuppression might have serious public health consequences.

Tagged: gondii, manipulation., sex ratio, strains, virulence, women

Reproduction

Schizophrenia and toxoplasmosis

October 26, 2009
Dion, S., Barbe, P. G., Leman, S., Camus, V., Dimier-Poisson, I.
M S-Medecine Sciences 2009; 25: 687-691.
Click for abstract
Schizophrenia and toxoplasmosis Schizophrenia is one of the most severe and disabling psychiatric disease that affects about 1% of the adult worldwide population. Aetiology of schizophrenia is still unknown but genetic and environmental factors are suspected to play a major role in its onset. Recent epidemiologic studies indicate that infectious agents may contribute to some cases of schizophrenia. In particular, several epidemiological, behavioural and neurochemical studies suggested the existence of an association between schizophrenia and post history of primo-infection by the Toxoplasma gondii. However, they are some limitations for this hypothesis among which the lack of correlation between the geographic distribution of both diseases and of direct evidence for the presence of the parasite in schizophrenic patients. Nevertheless the identification of physiopathological mechanisms related to the parasite could provide a better comprehension to the outcome of schizophrenia. Studies on the link between toxoplasmosis and schizophrenic may provide interesting data for the diagnosis and the development of new treatments for this disorder.

Tagged: 1st-episode, antibodies, Dopamine, Epidemiology, gondii, high-risk, infection, mental-disorders, metaanalysis, psychosis

Mental health

Higher prevalence of toxoplasmosis in victims of traffic accidents suggest increased risk of traffic accident in Toxoplasma-infected inhabitants of Istanbul and its suburbs.

October 26, 2009
Kocazeybek, B., Oner, Y. A., Turksoy, R., Babur, C., Cakan, H., Sahip, N., Unal, A., Ozaslan, A., Kilic, S., Saribas, S., Asian, M., Taylan, A., Koc, S., Dirican, A., Uner, H. B., Oz, V., Ertekin, C., Kucukbasmaci, O., Torun, M. M.
Forensic Science International 2009; 187: 103-108
Click for abstract
Reflexes of drivers who have toxoplasmosis have been shown to deteriorate from the actions of the parasitic cysts. The cysts can change the level of the neurotransmitters such as dopamine in the brain and by doing so extend the muscle response time and change personality profiles. In this Study, we aimed to determine the frequency of the latent toxoplasmosis (LT) in the driver population who were either injured or died in traffic accidents reported in Istanbul and its suburbs. We compared the results with a control group and discussed the relationship between the LT and the traffic accidents. We included 218 (89.7%) non-fatal, 25 (10.3%) fatal cases in our study as study groups. A total 243 subjects, 234 (96%) male, 9 (4%) female (who were alcohol negative) compared with 191 (95.5%) male and 9 (4.5%) female Subjects (control group) who had a traffic accident before but no history of toxoplasmosis were studied. Serologic tests, enzyme immunoassay (EIA) for IgG and IgM, and microimmunoflorescence (MIF) for IgG were used as the reference test, the Sabin-Feldman Dye test (SFDT) was used. According to serologic test results, LT seroprevalence in the study groups was 130 (53.5%) and in the control group 56 (28%) (p < 0.0001). A LT was present in 126 out of 234 (53.8%) males in the study groups, and 54 out of 191 (28.3%) males in the control group (p < 0.0001). In the 31-44 year age group, there was a significant difference with regard to toxoplasmosis between the study subjects and control groups (p < 0.0001). This difference was statistically very significant in (recent and former) cases with middle-aged men (31 44 years old). The results of this retrospective study Suggest that LT in drivers, especially those who are between 31 and 44 years might increase the risk for getting involved in a car accident. In a prospective study, Toxoplasma positive and negative subjects can be monitored before they are involved in a traffic accident to clarify the cause and result relationship. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

Tagged: antibodies, behavior, decreased level, Dopamine, forensic science, gondii, latent toxoplasmosis, mice, novelty seeking, personality, pregnant women, Schizophrenia, traffic accidents

Behavior

Psychosis may be associated with toxoplasmosis

October 26, 2009
Zhu S.
Medical Hypotheses 2009; 73: 799-801.
Click for abstract
Many parasites induce characteristic changes in their host. The effect of Toxoplasma gondii infection on the cerebrum and neuropsychiatric patients has been increasingly emphasized in recent years. T gondii has a high affinity for brain tissue where tachyzoites may form tissue cysts and persist for a life long time. Some psychiatric symptoms such as schizophrenia and mental retardation may be induced by the infection of T gondii. Furthermore, experiments demonstrated that some antipsychotics and mood stabilizers used to treat psychosis displayed the function of inhibiting T. gondii replication. Investigations from various regions in China in psychotic patients support the hypotheses that psychosis may be linked to T gondii infection. (C) 2009 Elsevier Ltd. All rights reserved.

Tagged: agents, behavior, Dopamine, gondii, host, infection, parasitosis, rats, risk, Schizophrenia

Mental health

Increased incidence of traffic accidents in Toxoplasma-infected military drivers and protective effect RhD molecule revealed by a large-scale prospective cohort study

January 9, 2009
Flegr, J., Klose, J., Novotná, M., Berenreitterová, M., Havlíček, J.
Bmc Infectious Diseases 2009; 9: Artn 72 10.1186/1471-2334-9-72
Click for abstract
Background: Latent toxoplasmosis, protozoan parasitosis with prevalence rates from 20 to 60% in most populations, is known to impair reaction times in infected subjects, which results, for example, in a higher risk of traffic accidents in subjects with this life-long infection. Two recent studies have reported that RhD-positive subjects, especially RhD heterozygotes, are protected against latent toxoplasmosis-induced impairment of reaction times. In the present study we searched for increased incidence of traffic accidents and for protective effect of RhD positivity in 3890 military drivers. Methods: Male draftees who attended the Central Military Hospital in Prague for regular entrance psychological examinations between 2000 and 2003 were tested for Toxoplasma infection and RhD phenotype at the beginning of their 1 to 1.5-year compulsory military service. Subsequently, the data on Toxoplasma infection and RhD phenotype were matched with those on traffic accidents from military police records and the effects of RhD phenotype and Toxoplasma infection on probability of traffic accident was estimated with logistic regression. Results: We confirmed, using for the first time a prospective cohort study design, increased risk of traffic accidents in Toxoplasma-infected subjects and demonstrated a strong protective effect of RhD positivity against the risk of traffic accidents posed by latent toxoplasmosis. Our results show that RhD-negative subjects with high titers of anti-Toxoplasma antibodies had a probability of a traffic accident of about 16.7%, i.e. a more than six times higher rate than Toxoplasma-free or RhD-positive subjects. Conclusion: Our results showed that a common infection by Toxoplasma gondii could have strong impact on the probability of traffic accident in RhD negative subjects. The observed effects could provide not only a clue to the long-standing evolutionary enigma of the origin of RhD polymorphism in humans (the effect of balancing selection), but might also be the missing piece in the puzzle of the physiological function of the RhD molecule.

Tagged: gondii, humans, latent toxoplasmosis, risk, testosterone

Behavior

Sex-dependent toxoplasmosis-associated differences in testosterone concentration in humans

January 9, 2008
Flegr, J., Lindová, J., Kodym, P.
Parasitology 2008; 135: 427-431
Click for abstract
Several lines of indirect evidence suggest that subjects with latent infection of the coccidian parasite Toxoplasma gondii have a higher concentration of testosterone than uninfected controls. Here, we searched for direct evidence of latent toxoplasmosis-associated differences in testosterone concentration among a Population of 174 female and 91 male students screened for Toxoplasma infection. We have found Toxoplasma-infected men to have a higher concentration of testosterone and Toxoplasma -infected women to have a lower concentration of testosterone than Toxoplasma -free controls. The opposite direction of the testosterone shift in men compared to women can explain the observed gender specificity of behavioural shifts in Toxoplasma- infected subjects.

Tagged: 2nd, 4th digit ratio, androgens, behaviour, complement-fixation, Dopamine, gender, gondii, hormones, human-behavior, infection, latent toxoplasmosis, manipulation., parasites, Toxoplasma

BehaviorPhysical health

Neurophysiological effect of the Rh factor. Protective role of the RhD molecule against Toxoplasma-induced impairment of reaction times in women

January 9, 2008
Flegr, J., Novotná, M., Lindová, J., Havlíček, J.
Neuroendocrinology Letters 2008; 29: 475-481
Click for abstract
BACKGROUND: The biological function of RhD protein, a major component of the Rh blood group system, is largely unknown. No phenotypic effect of RhD protein, except its role in hemolytic disease of newborns and protective role against Toxoplasma-induced impairment of reaction times in men, has been described. METHODS: Here we searched for a protective effect of RhD positivity against Toxoplasma-induced prolongation of reaction times in a set of 110 male and 226 female students of the Faculty of Science tested for latent toxoplasmosis and concentration of testosterone in saliva. RESULTS: RhD-positive subjects have been confirmed to be less sensitive to the influence of latent toxoplasmosis on reaction times than Rh-negative subjects. While a protective role of RhD positivity has been demonstrated previously in four populations of men, the present study has shown a similar effect in 226 female students. Our results have also shown that the concentration of testosterone in saliva strongly influences (reduces) reaction times (especially in men) and therefore, this factor should be controlled in future reaction times studies. CONCLUSIONS: The observed effects of RhD phenotype could provide not only a clue to the long-standing evolutionary enigma of the origin of RhD polymorphism in humans (the effect of balancing selection), differences in the RhD+ allele frequencies in geographically distinct populations (resulting from geographic variation in the prevalence of Toxoplasma gondii), but might also be the missing piece in the puzzle of the physiological function of the RhD molecule.

Tagged: balancing selection, behavioral-changes, blood antigen, blood group system., complement-fixation, evolution, gondii, heterozygous advantage, humans, latent toxoplasmosis, Parasite, psychomotor performance, Rhesus factor, testosterone

Cognitive functionsMotor functions

Meta-analysis of three case controlled studies and an ecological study into the link between cryptogenic epilepsy and chronic toxoplasmosis

October 29, 2007
Palmer, B. S.
Seizure-European Journal of Epilepsy 2007;16: 657-663
Click for abstract
A meta-analysis was performed on three case controlled studies which examined the relationship between latent toxoplasmosis gondii infection in the immunocompetent host and cryptogenic epilepsy. Further comparison was also made by examining the seroprevalence of toxoplasmosis rates for 17 various countries, cities or regions against the prevalence rates for epilepsy in those regions. Results: The results for the meta-analysis showed a Log-odds ratio of 4.8 which approximates to a similar relative risk, (Cl 2.6 to 7.8), with Cl for all three studies being above 1. Seroprevalence rates for toxoplasmosis and prevalence rates of epilepsy showed a strong association (p < 0.001). Discussion: The prevalence of toxoplasmosis is an important factor in the prevalence of epilepsy with a probable link in the cryptogenic epilepsies. An area with a reduced burden of toxoplasmosis will also have a reduced burden of epilepsy. Neuropathophysiology findings from various studies show a common physical relationship of microglial nodule formation in Toxoplasma gondii infection and epilepsy. This analysis raises the possibility that one of the many causes of epilepsy may be an infectious agent, or that cryptogenic epilepsy may be a consequence of Latent toxoplasmosis infection. This raises the possibility that public health measures to reduce toxoplasmosis infection may also result in a reduction in epilepsy.

Tagged: brazil, ecological study, encephalitis, Epidemiology, epilepsy, gondii, microglial nodule, microglial nodules, pathophysiology, population, pregnant women, prevalence, seroprevalence, Sweden, Toxoplasma gondii, toxoplasmosis

Mental health

Rats, cats, people and parasites: the impact of latent toxoplasmosis on behaviour

November 7, 2001
Webster, J. P.
Microbes and Infection 2001; 3: 1037-1045
Click for abstract
The manipulation hypothesis states a parasite may alter host behaviour for its own benefit, often by enhancing its transmission rate through the food chain. This paper reviews studies on the potential impact of one parasite, Toxoplasma gondii, on host behaviour, both on rodents, where altered responses may be proposed to benefit the parasite, and humans, where altered responses may arise as a side-effect of infection with no current adaptive significance. (C) 2001 Editions scientifiques et medicales Elsevier SAS.

Tagged: behaviour, congenital toxoplasmosis, gondii, infections, manipulation., mice, mouse, Parasite, personality, prevalence, rattus-norvegicus, toxoplasmosis, transmission, wild brown-rats

BehaviorMental health

Topics

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  • Cognitive functions 64
  • Mental health 439
  • Morphology 6
  • Motor functions 10
  • Personality 36
  • Physical health 134
  • Reproduction 36
  • Reviews 40
  • Sensory functions 3
  • Uncategorized 2

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  • Mortality Patterns of Toxoplasmosis and Its Comorbidities in Tanzania: A 10-Year Retrospective Hospital-Based Survey February 6, 2020
  • The role of latent toxoplasmosis in the aetiopathogenesis of schizophrenia–the risk factor or an indication of a contact with cat? February 6, 2020
  • The Association between Toxoplasma gondii Infection and Risk of Parkinson’s Disease: A Systematic Review and Meta-Analysis February 6, 2020

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