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Toxoplasma gondii & Human Phenotype

Compendium of Known Effects and Ongoing Research

novelty seeking

Presence of Toxoplasma gondii infection in brain as a potential cause of risky behavior: a report of 102 autopsy cases

February 1, 2020
Samojlowicz, D. Twarowska-Malczynska, J. Borowska-Solonynko, A. Poniatowski, L. A. Sharma, N. Olczak, M.
European Journal of Clinical Microbiology and Infectious Diseases 2019, 38: 305 - 317 Toxoplasma gondii Toxoplasmosis Brain Risky behavior Alcohol Mental health Drivers cerebral toxoplasmosis decreased level novelty seeking dopamine parasite host schizophrenia personality depression strategies
Click for abstract
Toxoplasmosis was linked to impairment in brain function, encompassing a wide range of behavioral and neuropsychiatric changes. Currently, the precise localization of Toxoplasma gondii in the human brain is limited and the parasite DNA was not found in population-based screening of autopsy cases. The aim of proposed study was to identify the presence of parasite DNA within the brain and its association with risky behavior and alcohol consumption in postmortem examination. Preliminarily, 102 cases with certain circumstances of death at time of forensic autopsy was included. Due to high risk of bias, the females were excluded from the analysis and final study group consists 97 cases divided into three groups: risky behavior, inconclusively risky behavior, and control group. The obtained tissue samples for Nested PCR covered four regions of the brain: symmetric left/right and anterior/posterior horns of lateral ventricles comprising lining ependyma and hippocampus. The second type of material comprised blood evaluated for antibodies prevalence using ELISA and alcohol concentration using HS-GC-FID. Analysis demonstrated 16.5% prevalence concerning the parasite DNA presence in examined brain tissue samples without specific distribution and association with age at death or days after death until an autopsy was performed. Results have shown correlation between occurrence of risky behavior leading to death and higher proportions of positive parasite DNA presence within the brain. Correlation was not observed between parasite DNA presence and excessive alcohol consumption. Conducted screening demonstrated correlation between parasite DNA presence in the brain with risky behavior and provided new information on possible effects of latent toxoplasmosis.

Tagged: alcohol, brain, Cerebral toxoplasmosis, decreased level, depression, health, host, mental, novelty seeking, Parasite, personality, risky behavior, Schizophrenia, Toxoplasma gondii, toxoplasmosis

BehaviorMental healthPersonality

Economic holobiont: Influence of parasites, microbiota and chemosignals on economic behavior

September 3, 2018
Houdek, P.
Frontiers in Behavioral Neuroscience 2018; 12
Click for abstract
The article is a perspective on utilization of microorganisms and chemosignals in studying human economic behavior. Research in biological roots of economic development has already confirmed that parasitic pressure influenced the creation and development of cultural norms and institutions. However, other effects of microorganisms on human groups and individual decision-making and behavior are heavily understudied. The perspective discusses how parasitic infections, sexually transmitted organisms and microbiota (i.e., "human holobiont") could causally influence risk-seeking behavior, impulsivity, social dominance, empathy, political views and gender differences. As a case study, the parasite Toxoplasma gondii and its influence on economic preferences, personal characteristics and human appearance are examined. I also briefly review how chemosignals influence decision-making, particularly in the social preferences domain. I mention some predictions that arise from the paradigm of economic holobiont for the economic science. The conclusion summarizes limitations of the discussed findings and the stated speculations.

Tagged: chemosignaling, decreased level, economics, family ties, fatal attraction, gender differences, gut-brain axis, latent toxoplasmosis, master possible influence, microbiota, novelty seeking, parasites, personality-traits, risk preferences, social preferences, time preferences, Toxoplasma gondii, toxoplasma gondii infection

Behavior

Toxoplasma gondii seropositivity and substance use in US adults

February 12, 2018
Berrett, A. N., Gale, S. D., Erickson,L. D., Thacker, E. L., Brown, B. L., Hedges, D. W.
Folia Parasitologica 2018; 65: 011
Click for abstract
The intracellular parasite Toxoplasma gondii (Nicolle et Manceaux, 1908) infects humans resulting in acute toxoplasmosis, an infection that in immunocompetent people is typically mild but results in persistent latent toxoplasmosis. In that T. gondii appears to affect dopamine synthesis and because addicting drugs affect midbrain dopamine transmission, latent toxoplasmosis could influence substance use. Using both the third and continuous National Health and Nutrition Examination Surveys from the US Centers for Disease Control and Prevention, we used logistic regression to test for associations between T. gondii seropositivity and subject self-report of having ever used tobacco, alcohol, marijuana, cocaine, heroin, or methamphetamine. In the third NHANES dataset, which included data for tobacco, alcohol, marijuana and cocaine, T. gondii seropositivity was associated with a reduced likelihood of self-reported marijuana (OR = 0.71 [95% CI: 0.58; 0.87]; p = 0.001) and cocaine use (OR = 0.72 [95% CI: 0.56; 0.91]; p = 0.006). In the continuous National Health and Nutrition Examination Surveys dataset, which included data for all six substances, T. gondii seropositivity was associated with a reduced likelihood of self-reported tobacco (OR = 0.87 [95% CI: 0.76; 1.00]; p = 0.044), marijuana (OR = 0.60 [95% CI: 0.50; 0.72]; p < 0.001), heroin (OR = 0.60 [95% CI: 0.42; 0.85]; p = 0.005) and methamphetamine use (OR = 0.54 [95% CI: 0.38; 0.77]; p = 0.001). We observed interactions between sex and T. gondii seropositivity in the prediction of self-reported use of tobacco and alcohol. Further, T. gondii seropositivity appeared to remove the protective effect of education and economic status against self-reported cigarette smoking. These findings suggest that T. gondii seropositivity may be inversely associated with some but not all types of substance use in US adults.

Tagged: addiction, alcohol, Cocaine, decreased level, Dopamine, drug use, heroin, hypothesis, impulsivity, infection, marijuana, methamphetamine, novelty seeking, receptor, Schizophrenia, seroprevalence, tobacco, toxoplasmosis

Behavior

Toxoplasmosis as a cause for behaviour disorders – overview of evidence and mechanisms

October 19, 2010
Fekadu A, Shibre T, Cleare AJ.
Folia Parasitologica 2010; 57: 105-113
Click for abstract
Background - There is growing interest in the role of microbial agents in the causation of psychiatric disorders. The neurotropic protozoan parasite Toxoplasma gondii is one of the main candidates and has been associated with various psychiatric conditions, including schizophrenia. Methods - A narrative review of the literature from the main medical databases (Medline, PubMed, PsycINFO), Google Scholar and Google using combinations of applicable terms. Results - T. gondii affects the brain in both the acute and the latent stages of infection causing apparent brain pathologies in infected rodents and both immuno-compromised and immuno-competent humans. In immuno-competent individuals, behavioural disorders are primarily related to the latent stages of the illness. Behavioural/mental disorders that include schizophrenia, mood disorders, personality changes and cognitive impairments may be related to infection with T gondii. Evidence for a behavioural effect of T gondii comes from observational reports in animal models and controlled behavioural analysis in humans. Indirect clues of infection also come from raised seroprevalence or serotitres of antitoxoplasma antibodies among those with mental disorders. The pathophysiologic mechanism through which T gondii may exert its effect is not clear, but direct impact on the brain and changes in neuroimmunomodulation, neurotransmission and some gene-environment interactions are postulated. Conclusion - There is evidence supporting a potential role of T gondii infection in the onset of some behavioural disorders. Confirmation of such a role would prove a significant breakthrough in the search for the aetiology, treatment and prevention of behavioural disorders, such as schizophrenia. However, the associations remain preliminary.

Tagged: 1st-episode schizophrenia, agents, antibodies, behavioural disorder, decreased level, gondii infection, individuals, mental-health surveys, mood, mood disorders, novelty seeking, personality changes, review, risk, Schizophrenia, Toxoplasma gondii, toxoplasmosis

Mental healthReviews

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

Epidemiological evidences from China assume that psychiatric-related diseases may be associated with Toxoplasma gondii infection

January 4, 2007
Zhu, S., Guo, M. F., Feng, Q. C., Fan, J. M.,
Neuroendocrinology Letters, 2007, 28: 115-120
Click for abstract
In recent years, the effect of Toxoplasma gondii infection on psychiatric-related aspects has been increasingly recognized. T gondii has a high affinity for brain tissue where tachyzoites may form tissue cysts and persist life long. In recent years, 15 serological surveys about T gondii infection and psychiatric diseases have been carried out in different areas in China. Studies showed that the prevalence of antibodies against T gondii in psychotic patients was much higher than in normal persons; statistically differences were significant. Studies also reported that raising cats or enjoying the habit of eating raw or under cooked meet were potential risk factors for the infection of T gondii. The epidemiological and serological evidence support the hypothesis that some psychiatric diseases such as schizophrenia or mental retardation might be linked to T gondii infection.

Tagged: 1st-episode schizophrenia, antibodies, behavior, cats, host, novelty seeking, parasites, personality changes, psychiatric-related disease, rattus-norvegicus, toxoplasmosis

Mental health

Can the common brain parasite, Toxoplasma gondii, influence human culture?

October 30, 2006
Lafferty, K.D.
Proceedings of the Royal Society B-Biological Sciences 2006; 273: 2749-2755.
Click for abstract
The latent prevalence of a long-lived and common brain parasite, Toxoplasma gondii, explains a statistically significant portion of the variance in aggregate neuroticisin among populations, as well as in the 'neurotic' cultural dimensions of sex roles and uncertainty avoidance. Spurious or non-causal correlations between aggregate personality and aspects of climate and culture that influence T gondii transmission could also drive these patterns. A link between culture and T gondii hypothetically results from a behavioural manipulation that the parasite uses to increase its transmission to the next host in the life cycle: a cat. While latent toxoplasmosis is usually benign, the parasite's subtle effect on individual personality appears to alter the aggregate personality at the population level. Drivers of the geographical variation in the prevalence of this parasite include the effects of climate on the persistence of infectious stages in soil, the cultural practices of food preparation and cats as pets. Some variation in culture, therefore, may ultimately be related to how climate affects the distribution of T gondii, though the results only explain a fraction of the variation in two of the four cultural dimensions, suggesting that if T gondii does influence human culture, it is only one among many factors.

Tagged: antibodies, decreased level, Dopamine, infection, masculinity, nations, neuroticism, novelty seeking, personality, personality changes, population, pregnant women, prevalence, risk factors, uncertainty avoidance

BehaviorPersonality

Topics

  • Behavior 105
  • 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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Recent articles

  • 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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