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

Toxoplasma gondii (Nicolle et Manceaux, 1908), an intracellular parasite that causes toxoplasmosis, infects a third of the human population. Latent toxoplasmosis has been linked to altered immune responses, including elevated proinflammatory cytokines. In early pregnancy, the immune system adapts to balance inflammation and foetal tolerance. This study assessed whether pregnant women in the first trimester infected with Toxoplasma gondii have different cytokine levels than uninfected women. This study also examined whether women with discordant test results for toxoplasmosis represent a distinct group or a mixed group composed of infected women with unusually low levels of anti-Toxoplasma antibodies and uninfected women with high levels of cross-reacting antibodies. We measured 18 cytokines (IL-1β, IL-1ra, IL-2, IL-4, IL-7, IL-9, IL-17A, Eotaxin, FGF basic, G-CSF, IFN-γ, IP-10, MCP-1, MIP-1α, MIP-1β, PDGF-BB, RANTES, TNF-α) in 78 pregnant women, classified as Toxoplasma-positive, Toxoplasma-negative or Toxoplasma-discordant (negative by IgG ELISA, positive by complement fixation test [CFT]). Using exploratory factor analysis, we identified two factors, the first explaining 29.6% and the second 24.9% of the total variability in cytokine concentrations. Toxoplasma-positive women scored significantly higher in the second factor, primarily associated with cytokines linked to Th1-driven inflammation and cellular immunity. Specifically, these women exhibited elevated levels of IL-1β, IL-1ra, IL-2, FGF basic and PDGF-BB compared to Toxoplasma-negative women. This finding suggests that pregnant women with latent toxoplasmosis experience some degree of chronic inflammation. Additionally, our results indicate that Toxoplasma-discordant women are likely Toxoplasma-negative individuals with detectable anti-Toxoplasma IgM antibodies. However, as this study focused on pregnant women, further research is necessary to validate these conclusions in broader populations.

• Klíčová slova
• Toxoplasma gondii, cytokines, immunity, pregnancy,
• MeSH
• cytokiny krev   MeSH
• dospělí MeSH
• latentní infekce * MeSH
• lidé MeSH
• mladý dospělý MeSH
• parazitární komplikace těhotenství * imunologie   diagnóza   MeSH
• protilátky protozoální krev   MeSH
• sérologické testy MeSH
• těhotenství MeSH
• Toxoplasma imunologie   MeSH
• toxoplazmóza * diagnóza   imunologie   MeSH
• zánět * imunologie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladý dospělý MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cytokiny MeSH
• protilátky protozoální 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

BACKGROUND: Toxoplasmosis is becoming a global health hazard as it infects 30-50% of the world human population. Clinically, the life-long presence of the parasite in tissues of a majority of infected individuals is usually considered asymptomatic. However, a number of studies show that this 'asymptomatic infection' may also lead to development of other human pathologies. AIMS OF THE STUDY: The purpose of the study was to collect available geoepidemiological data on seroprevalence of toxoplasmosis and search for its relationship with mortality and disability rates in different countries. METHODS AND FINDINGS: Prevalence data published between 1995-2008 for women in child-bearing age were collected for 88 countries (29 European). The association between prevalence of toxoplasmosis and specific disease burden estimated with age-standardized Disability Adjusted Life Year (DALY) or with mortality, was calculated using General Linear Method with Gross Domestic Product per capita (GDP), geolatitude and humidity as covariates, and also using nonparametric partial Kendall correlation test with GDP as a covariate. The prevalence of toxoplasmosis correlated with specific disease burden in particular countries explaining 23% of variability in disease burden in Europe. The analyses revealed that for example, DALY of 23 of 128 analyzed diseases and disease categories on the WHO list showed correlations (18 positive, 5 negative) with prevalence of toxoplasmosis and another 12 diseases showed positive trends (p<0.1). For several obtained significant correlations between the seroprevalence of toxoplasmosis and specific diseases/clinical entities, possible pathophysiological, biochemical and molecular explanations are presented. CONCLUSIONS: The seroprevalence of toxoplasmosis correlated with various disease burden. Statistical associations does not necessarily mean causality. The precautionary principle suggests however that possible role of toxoplasmosis as a triggering factor responsible for development of several clinical entities deserves much more attention and financial support both in everyday medical practice and future clinical research.

• MeSH
• asymptomatické nemoci epidemiologie   MeSH
• dopravní nehody statistika a číselné údaje   MeSH
• hrubý domácí produkt MeSH
• internacionalita * MeSH
• kvalitativně upravené roky života MeSH
• lidé MeSH
• prevalence MeSH
• sebevražda statistika a číselné údaje   MeSH
• séroepidemiologické studie MeSH
• toxoplazmóza krev   epidemiologie   mortalita   přenos   MeSH
• vlhkost MeSH
• zeměpis MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH