Over the past three turbulent decades, research has profoundly reshaped our understanding of chronic Toxoplasma gondii infection-traditionally regarded as harmless in immunocompetent individuals-unveiling its surprising impact on human health, performance, and behavior. This review emphasizes the effects of chronic Toxoplasma infection on physical and mental health, cognitive performance, and behavioral changes, highlighting key findings from studies investigating these domains, with a particular focus on both ultimate and proximate mechanisms underlying the observed effects. To this end, the primary focus will be on human studies; however, animal model studies will also be thoroughly considered when necessary and appropriate, to provide context and additional important information. Research demonstrates that chronic Toxoplasma infection may contribute to a broad spectrum of physical health issues. Ecological studies have revealed correlations between toxoplasmosis prevalence and increased morbidity and mortality from various conditions, including cardiovascular diseases, neurological disorders, and certain cancers. Large-scale cross-sectional studies have further shown that infected individuals report a higher incidence of numerous health complaints and diagnosed diseases, suggesting a significant impact on overall physical well-being. In addition to physical health, lifelong Toxoplasma infection (subclinical toxoplasmosis) has been implicated in cognitive impairments and behavioral changes. Studies have reported associations between infection and poorer performance in areas such as reaction time, processing speed, working memory, and executive function. Many of these behavioral changes likely relate to worsened health and a shift towards a "fast life history strategy." These cognitive deficits can have significant implications for daily functioning and performance. Furthermore, the role of Toxoplasma infection in the development or exacerbation of mental health disorders has been extensively investigated. Meta-analyses, ecological studies, and large-scale observational studies have demonstrated associations between Toxoplasma infection and an increased risk of disorders such as schizophrenia and obsessive-compulsive disorder. While the precise mechanisms underlying these associations remain under investigation, research suggests that neuroinflammation and alterations in neurotransmitter systems are likely to play a role. Far from being harmless, subclinical toxoplasmosis is increasingly recognized as a hidden factor influencing human health, behavior, and cognitive performance-with implications that extend well beyond the individual to public health at large. Further research is warranted to elucidate the complex interplay between Toxoplasma infection, host physiology, and the development of various physical, cognitive, behavioral, and mental health conditions.

• Klíčová slova
• OCD, RhD, Rhesus D antigen, autism, evolution, intelligence, manipulation hypothesis, mental health, parasite, schizophrenia, subclinical toxoplasmosis, testosterone,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Latent infection with Toxoplasma gondii (Nicolle et Manceaux, 1908) has been repeatedly correlated with behavioural and physiological changes in both humans and animals. While classically regarded as a parasite transmitted via ingestion or vertical (transplacental) transmission, accumulating evidence suggests that sexual transmission may also contribute to its epidemiology. This review explores the hypothesis that some behavioural effects of toxoplasmosis - especially those related to attraction, sexual activity, and mate choice - may have evolved to facilitate sexual transmission of the parasite. We summarise findings from animal models and human studies that show modified sexual preferences, altered sexual activity, enhanced attractiveness in infected individuals, and elevated prevalence of T. gondii in groups exhibiting high sexual activity or non-traditional sexual behaviour patterns. Particular attention is given to the role of testosterone, which may mediate both behavioural changes and reproductive consequences, such as shifts in offspring sex ratios and fertility outcomes. Direct detection of the parasite in semen and evidence of transmission through insemination in non-human species further support the plausibility of this route. The observed behavioural effects may also intersect with mechanisms previously thought to enhance predation risk, such as altered fear responses to felid odours. Taken together, these findings point to the possibility that sexual transmission, while likely secondary in humans, may have played a more substantial role in the evolutionary history and current ecology of T. gondii than previously appreciated. This perspective also provides an alternative interpretative framework for understanding the broad spectrum of phenotypic changes associated with latent toxoplasmosis. Further interdisciplinary research is required to clarify the relative contribution of sexual transmission to the parasite's life cycle and to assess its implications for public health and theory of host-parasite coevolution.

• Klíčová slova
• manipulation, parasite manipulation., review, sexual behaviour, sexually transmitted diseases, testosterone, toxoplasmosis,
• MeSH
• interakce hostitele a parazita * MeSH
• lidé MeSH
• sexuální chování MeSH
• Toxoplasma * fyziologie   MeSH
• toxoplazmóza * přenos   parazitologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

In this article, I recount the journey of discovering the effects of latent toxoplasmosis on human psychology, behaviour, morphology, and health as I observed it from the closest perspective over the past 30+ years, during which our laboratory has been intensely focused on this research. I trace how we moved from the initial observations of differences between infected and uninfected individuals in certain personality traits to the systematic study of similar differences in behaviour, both in the laboratory and in everyday life, as well as in physiological and even morphological traits. This eventually led us to investigate the causal relationships behind these observed associations and their molecular basis. I describe some of the unexpected discoveries our research revealed - whether it was the impact of toxoplasmosis on the human sexual index, the prenatal and postnatal development, the sexual preferences and behaviour, the modulatory effect of blood Rh factor on toxoplasmosis, or the discovery of sexual transmission of toxoplasmosis. In exploring whether the toxoplasmosis-associated effects were merely side effects of an ongoing latent infection, we gradually uncovered that seemingly asymptomatic toxoplasmosis has profound (and certainly not positive) effects on the mental and physical health of infected individuals. The article also includes three separate boxes that discuss some key methodological challenges we encountered along the way, such as how to distinguish the effect of infection from mere statistical association, or how to differentiate parasitic manipulation from a simple side effect.

• Klíčová slova
• Rh factor, Toxoplasma, behaviour, chronic toxoplasmosis, dopamine, manipulation, mental health, morbidity, parasite., personality, physical health, schizophrenia, sex ratio, testosterone,
• MeSH
• dějiny 20. století MeSH
• dějiny 21. století MeSH
• lidé MeSH
• sexuální chování MeSH
• toxoplazmóza * psychologie   patofyziologie   parazitologie   MeSH
• zvířata MeSH
• Check Tag
• dějiny 20. století MeSH
• dějiny 21. století MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• historické články MeSH
• přehledy MeSH

One-third of humanity harbors a lifelong infection with Toxoplasma gondii, and probably about 80% are infected with human cytomegalovirus (CMV). This study aims to delineate the associations between toxoplasmosis and cognitive abilities and compare these to the associations with CMV. We evaluated the cognitive performance of 557 students, who had been examined for Toxoplasma and CMV infections, using intelligence, memory, and psychomotor tests. The results indicated cognitive impairments in seropositive individuals for both pathogens, with variations in cognitive impact related to sex and the Rh factor. Specifically, Toxoplasma infection was associated with lower IQ in men, whereas CMV was predominantly associated with worse performance by women when testing memory and reaction speeds. Analysis of the antibody concentrations indicated that certain Toxoplasma-associated cognitive detrimental effects may wane (impaired intelligence) or worsen (impaired reaction times) over time following infection. The findings imply that the cognitive impairments caused by both neurotropic pathogens are likely due to pathological changes in the brain rather than from direct manipulative action by the parasites.

• Klíčová slova
• Rh factor, behavior, cognition, cytomegalovirus, intelligence, manipulation hypothesis, memory, parasite, psychomotor performance, toxoplasmosis,
• MeSH
• cytomegalovirové infekce * imunologie   epidemiologie   MeSH
• Cytomegalovirus * imunologie   MeSH
• dospělí MeSH
• kognice * MeSH
• krevní skupiny - systém Rh-Hr imunologie   MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• průřezové studie MeSH
• sexuální faktory MeSH
• Toxoplasma * imunologie   MeSH
• toxoplazmóza * psychologie   imunologie   epidemiologie   komplikace   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• krevní skupiny - systém Rh-Hr MeSH

Humans infected by Toxoplasma gondii express no specific symptoms but manifest higher incidence of many diseases, disorders and differences in personality and behavior. The aim of this study was to compare the political beliefs and values of Toxoplasma-infected and Toxoplasma-free participants. We measured beliefs and values of 2315 responders via an online survey (477 Toxoplasma-infected) using the Political Beliefs and Values Inventory (PI34). This study showed Toxoplasma-infected and Toxoplasma-free participants of our cross-sectional study differed in three of four factors of PI34, scoring higher in Tribalism and lower in Cultural liberalism and Anti-Authoritarianism. We found sex differences in political beliefs associated with Toxoplasma infection. Infected women scored higher in tribalism and lower in cultural liberalism, compared with the Toxoplasma-free control group, while infected men scored higher in economic equity. These results fit with sexual differences in behavior and attitude observed after toxoplasmosis infection. Controlling for the effect of worse physical health and mental health had little impact, suggesting that impaired health did not cause these changes. Rather than adaptation to prevalence of parasites, as suggested by parasite-stress theory, the differences might be side-effects of long-term mild inflammatory reaction. However, to get clear picture of the mild inflammation effects, more research focused on different infectious diseases is needed.

• Klíčová slova
• Toxoplasma gondii, infectious diseases, manipulation hypothesis, parasite threat, pathogen avoidance, political beliefs, stress,
• MeSH
• lidé MeSH
• osobnost MeSH
• průřezové studie MeSH
• sexuální chování MeSH
• Toxoplasma * MeSH
• toxoplazmóza * komplikace   epidemiologie   parazitologie   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Toxoplasmosis is one of the world's most prevalent zoonoses. The causative agent, Toxoplasma gondii (Nicolle et Manceaux, 1908) is a facultative heteroxenic, polyxenic apicomplexan protist. There are several potential pathways of transmission within and between host species. Most infections with T. gondii result from close contact with pets/cats, ingestion of tissue cysts in undercooked meat of infected animals, and oocysts from food or water contaminated by feline faeces. Recently, epidemiological studies have shown that T. gondii infection plays a prominent role in the pathogenesis of several psychiatric disorders. This report reviews the association between T. gondii infection and patients with psychiatric disorders, particularly schizophrenia, depressive disorders and bipolar disorders.

• Klíčová slova
• bipolar disorders, depressive disorders, mental disorders, schizophrenia, toxoplasmosis,
• MeSH
• duševní poruchy * komplikace   MeSH
• kočky MeSH
• lidé MeSH
• oocysty MeSH
• Toxoplasma * MeSH
• toxoplazmóza zvířat * komplikace   epidemiologie   MeSH
• zoonózy MeSH
• zvířata MeSH
• Check Tag
• kočky MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Statistically, the concentration of antibodies against parasites decreases with the duration of infection. This can result in false-negative outcomes of diagnostic tests for subjects with old infections. When a property of seronegative and seropositive subjects is compared under these circumstances, the statistical tests can detect no difference between these two groups of subjects, despite the fact that they differ. When the effect of the infection has a cumulative character and subjects with older infections are affected to a greater degree, we may even get paradoxical results of the comparison - the seropositive subjects have, on average, a higher value of certain traits despite the infection having a negative effect on those traits. A permutation test for the contaminated data implemented, e.g. in the program Treept or available as a comprehensibly commented R function at https://github.com/costlysignalling/Permutation_test_for_contaminated_data, can be used to reveal and to eliminate the effect of false negatives. A Monte Carlo simulation in the program R showed that our permutation test is a conservative test - it could provide false negative, but not false positive, results if the studied population contains no false-negative subjects. A new R version of the test was expanded by skewness analysis, which helps to estimate the proportion of false-negative subjects based on the assumption of equal data skewness in groups of healthy and infected subjects. Based on the results of simulations and our experience with empirical studies we recommend the usage of a permutation test for contaminated data whenever seronegative and seropositive individuals are compared.

• Klíčová slova
• Case-control studies, Epidemiology, Randomisation tests, Sensitivity, Serology, Specificity, Toxoplasma,
• MeSH
• biologie * metody   MeSH
• individualizovaná medicína * metody   MeSH
• lidé MeSH
• mutační analýza DNA * metody   normy   MeSH
• senzitivita a specificita MeSH
• software * MeSH
• studie případů a kontrol MeSH
• výpočetní biologie metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUNDS: The prevalence of toxoplasmosis is higher in schizophrenics than in the general population. It has been suggested that certain symptoms of schizophrenia, including changes in olfactory functions, are in fact symptoms of toxoplasmosis that can be easily detected in schizophrenics only due to the increased prevalence of toxoplasmosis in this population. Schizophrenics have impaired identification of odors and lower sensitivity of odor detection, however, no information about these parameters of non-schizophrenic Toxoplasma-infected subjects is available. METHODS: Here we searched for differences in olfactory functions between 62 infected and 61 noninfected non-schizophrenic subjects using the case-controls experimental design. RESULTS: The infected men scored better than the non-infected controls in the standard odor-identification test. The infected women rated all smells as more intensive while the infected men rated nearly all smells as less intensive. Infected women rated the pleasantness of the smell of the cat urine as higher than the non-infected women and the opposite was true for the men-in contrast, higher pleasantness of odor in infected men and lower in infected women were observed and described in the 2011 study. Toxoplasmosis, Rh, and toxoplasmosis-Rh interaction were not associated with the rated pleasantness of the smell of other stimuli. However, our sample contained only 17 Rh negative men and 30 Rh negative women. Therefore, all results concerning the main effects of Rh factor and the interaction with Rh factor must be considered only preliminary. CONCLUSIONS: Our results suggest that latent toxoplasmosis is associated with changes in the olfactory functions in humans; however, the observed changes differ from those observed in schizophrenics.

• MeSH
• dospělí MeSH
• kočky MeSH
• krevní skupiny - systém Rh-Hr metabolismus   MeSH
• lidé MeSH
• mladý dospělý MeSH
• moč MeSH
• odoranty MeSH
• schizofrenie metabolismus   parazitologie   patofyziologie   MeSH
• studie případů a kontrol MeSH
• Toxoplasma patogenita   MeSH
• toxoplazmóza metabolismus   patofyziologie   MeSH
• zvířata MeSH
• Check Tag
• dospělí MeSH
• kočky MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• krevní skupiny - systém Rh-Hr MeSH

BACKGROUND: Toxoplasma, a protozoan parasite of cats, infects many species of intermediate and paratenic hosts, including about one-third of humans worldwide. After a short phase of acute infection, the tissue cysts containing slowly dividing bradyzoites are formed in various organs and toxoplasmosis proceeds spontaneously in its latent form. In immunocompetent subjects, latent toxoplasmosis was considered asymptomatic. However, dozens of studies performed on animals and humans in the past twenty years have shown that it is accompanied by a broad spectrum of specific behavioural, physiological and even morphological changes. In human hosts, the changes often go in the opposite direction in men and women, and are mostly weaker or non-existent in Rh-positive subjects. METHODS: Here, we searched for the indices of lower endurance of the infected subjects by examining the performance of nearly five hundred university students tested for toxoplasmosis and Rh phenotype in two tests, a weight holding test and a grip test. RESULTS: The results confirmed the existence of a negative association of latent toxoplasmosis with the performance of students, especially Rh-negative men, in these tests. Surprisingly, but in an accordance with some already published data, Toxoplasma-infected, Rh-positive subjects expressed a higher, rather than lower, performance in our endurance tests. DISCUSSION: Therefore, the results only partly support the hypothesis for the lower endurance of Toxoplasma infected subjects as the performance of Rh-positive subjects (representing majority of population) correlated positively with the Toxoplasma infection.

• MeSH
• fyzická vytrvalost * MeSH
• imunoglobulin G krev   MeSH
• imunoglobulin M krev   MeSH
• krevní skupiny - systém Rh-Hr krev   MeSH
• lidé MeSH
• mladý dospělý MeSH
• protilátky protozoální krev   MeSH
• síla ruky * MeSH
• Toxoplasma imunologie   MeSH
• toxoplazmóza patofyziologie   MeSH
• Check Tag
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• imunoglobulin G MeSH
• imunoglobulin M MeSH
• krevní skupiny - systém Rh-Hr MeSH
• protilátky protozoální MeSH

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.

• Klíčová slova
• Toxoplasma gondii, chemosignaling, economics, microbiota, parasites, risk preferences, social preferences, time preferences,
• Publikační typ
• časopisecké články MeSH