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Introduction
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Publications
Publications (63)
Disgust plays a significant role in pathogen protection, with research highlighting the distinct contributions of various sensory modalities to the complex disgust reaction. In our study, 113 participants touched 6 hidden objects, rating their tactile disgust, fear, and object characteristics. Participants also completed the Disgust Scale-Revised,...
Introduction: Latent toxoplasmosis, affecting approximately one-third of people worldwide, was once thought to be asymptomatic. However, studies in the last three decades have revealed that it can cause significant psychological and behavioral changes in humans. The observation that the behavioral impacts of toxoplasmosis manifest in opposite direc...
This paper advocates for considering disgust as a primary emotional system within Panksepp’s Affective Neuroscience framework, which has the potential to improve the efficacy of psychotherapy with obsessive-compulsive disorder, hypochondriasis, and emetophobia. In 2007, Toronchuk and Ellis provided comprehensive evidence that DISGUST system, as the...
The emotion of disgust protects individuals against pathogens, and it has been found to be elevated during pregnancy. Physiological mechanisms discussed in relation to these changes include immune markers and progesterone levels. This study aimed to assess the association between steroids and disgust sensitivity in pregnancy. Using a prospective lo...
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 b...
Toxoplasma gondii is one of the most widespread parasites in the human population globally. Several modes of its transmission have been proposed: some are well-researched and confirmed, others remain unconfirmed. One unconfirmed hypothesis pertains to potential transmission of Toxoplasma gondii via oral sex (fellatio) in humans. A recent study foun...
The emotion of disgust protects individuals against pathogens, and it has been found that during pregnancy, it is elevated. Physiological mechanisms discussed in relation to these changes include immune markers and progesterone levels. The aim of this study is to assess the association between steroids and disgust in pregnancy. In a sample of 179 p...
One proposal for the persistence of homosexuality in the human population is the sexually antagonistic gene hypothesis, which suggests that the lower fertility of homosexual individuals, especially men, may be compensated by higher fertility of their relatives of the opposite sex. To test this hypothesis, we have collected data from 7,312 heterosex...
One-third of humanity harbors a lifelong infection with Toxoplasma gondii . This parasite undergoes sexual reproduction in cats and asexual reproduction in any warm-blooded intermediate hosts. The cycle progresses as cats ingest these hosts, containing the parasite’s tissue cysts. Such infections can alter behaviors in both animals and humans, pote...
Considered a part of the behavioral immune system, disgust functions as a protective mechanism against po- tential pathogen threat. There is evidence that disgust sensitivity varies depending on immunological and hor- monal changes, including those occurring during the menstrual cycle or pregnancy. Although some studies indicate that disgust is ele...
Human populations, especially European, are polymorphic in the RHD gene. A significant fraction of their members carries two copies of a mutated (deleted) allele, which results in their Rh-negative blood type. Theoretically, this polymorphism should be unstable. Carriers of the less frequent allele are penalized by reduced fertility because of the...
Human populations, especially European, are polymorphic in the RHD gene. A significant fraction of their members carries two copies of a mutated (deleted) allele, which results in their Rh-negative blood type. Theoretically, this polymorphism should be unstable. Carriers of the less frequent allele are penalized by reduced fertility because of the...
The behavioral immune system, with disgust as its motivational part, serves as the first line of defense in organisms’ protection against pathogens. Laboratory studies indicate that disgust sensitivity adaptively adjusts to simulated environmental threat, but whether disgust levels similarly change in response to real-life threats, such as a pandem...
Elevated levels of nausea and vomiting in pregnancy (NVP) and disgust sensitivity have been observed in the first trimester and both are thought to have a protective function for the mother and her fetus. Their aetiology is not clear, however, with previous studies attributing elevated NVP and disgust to various factors including endocrine changes,...
Disgust is an essential part of the behavioral immune system, protecting the individual from infection. According to the Compensatory Prophylaxis Hypothesis (CPH), disgust sensitivity increases in times of immunosuppression, potentially including pregnancy. We aimed to replicate a previous study observing longitudinal changes in disgust sensitivity...
Background
A recent study focusing on dietary predictors of nausea and vomiting in pregnancy (NVP) found that women with higher levels of partner support, and those who had used oral contraception (OC) when they met the father, both tended to report less severe NVP compared with previous non-users or those with less supportive partners. We provide...
Introduction
Considered a part of the behavioral immune system (BIS), disgust sensitivity is expected to be adjusting as a response to the actual level of the environmental health risks.
Methods
In this preregistered study, we tested the hypothesis that disgust sensitivity would be higher during the COVID-19 pandemic compared to the pre-pandemic p...
Women with red hair color, i.e., 1–9% of female Europeans, tend to be the subject of various stereotypes about their sexually liberated behavior. The aim of the present case–control study was to explore whether a connection between red hair color and sexual behavior really exists using data from 110 women (34% redheaded) and 93 men (22% redheaded)....
Objectives
Toxoplasma gondii is a widely prevalent protozoan parasite in human populations. This parasite is thought to be primarily transmitted through undercooked meat and contamination by cat feces. Here, we seek to determine if Toxoplasma gondii cysts can be found within human semen.
Methods
We used a mixture of histological and immunofluoresc...
Background: A recent study focusing on dietary predictors of nausea and vomiting in pregnancy (NVP) found that women with higher levels of partner support, and those who had use oral contraception (OC) when they met the father, both tended to report less severe NVP compared with previous non-users or those with less supportive partners. We provide...
According to the Compensatory Prophylaxis Hypothesis (CPH), disgust may be considered a part of the behavioral immune system, adjusting as a function of immunocompetence. Early pregnancy involves modulation of a complex network of various immune-related factors, but only a few studies so far have focused on disgust sensitivity in pregnant women in...
Life-long infection with Toxoplasma , which affects 30% of the human population, has specific behavioral effects. The stress-coping hypothesis explains why the toxoplasmosis-associated behavioral changes go in opposite directions in men and women. It suggests that toxoplasmosis impairs the health of humans, which results in chronic stress. Men and...
Regarding the fact that gay men leave less offspring than straight men, it is appropriate to raise a question by which means is male homosexuality maintained in a population and what could eventually be its evolutionary role. The aim of this paper is to summarize theories that try to explain male homosexuality within the framework of evolution. Fur...
Human populations, especially European, are polymorphic in the RHD gene. A significant fraction of their members carry no copy of the coding section of RHD gene, which results in their Rh-negative blood type. Theoretically, this polymorphism should be unstable. Carriers of the less frequent allele are penalized by reduced fertility because of the i...
Toxoplasma gondii is a widely prevalent protozoan parasite in human populations. This parasite is thought to be primarily transmitted through undercooked meat and contamination by cat feces. Here, we demonstrate that Toxoplasma gondii cysts can be found within human semen, thus suggesting a potential for sexual transmission. We visualized Toxoplasm...
Women with red hair colour, i.e., 1–9% of female Europeans, tend to be the subject of various stereotypes about their sexually liberated behaviour. The aim of the present case-control study was to explore whether a connection between red hair colour and sexual behaviour really exists using data from 110 women (34% redheaded) and 93 men (22% redhead...
According to the congruency hypothesis, relationship satisfaction is predicted by the congruency (or non-congruency) between current use of oral contraceptives (OC) and their use during relationship formation. This is based on reports that OC may alter women’s mate preferences, so that attraction to their partner may have changed in non-congruent w...
Latent infection of the globally spread parasite Toxoplasma gondii in humans has been associated with changes in personality and behavior. Numerous studies have investigated the effect of toxoplasmosis on depression, but their results are inconsistent. Our study focused on the effect of latent toxoplasmosis on depression in men and women in associa...
Human populations, especially European, are polymorphic in the RHD gene. A significant fraction of their members carries two copies of a mutated (deleted) allele, which results in their Rh-negative blood type. Theoretically, this polymorphism should be unstable. Carriers of the less frequent allele are penalized by reduced fertility because of the...
Numerous recent studies show that vitamin D deficiency potentiates various chronic physical and psychiatric disorders and diseases. It has been shown that a similar range of disorders is also associated with latent infection with Toxoplasma gondii (Nicolle et Manceaux, 1908). For instance, among cancer, diabetes and schizophrenia patients, we find...
Background
About a third of people in the world are infected with Toxoplasma gondii. This parasite has been found in the reproductive organs and semen of males of many animal species as well as humans. The effects of toxoplasmosis on sperm count, motility, and morphology were confirmed in rats. A higher prevalence of toxoplasmosis has been observed...
Maintenance of genetic polymorphism remains one of the big questions of evolutionary biology, which for a long time tended to be explained by balancing selection. This explanation was later criticized, but now is again accepted as an important mechanism in evolution. Human blood group systems seem affected by balancing selection especially strongly...
Toxoplasmosis is one of the most widespread human parasitoses in developed countries. Sexual transmission has been confirmed in several animal species, and indirect evidence suggests that it may occur in humans. We compared the seropositivity to Toxoplasma gondii in couples who visited the Center for Assisted Reproduction in Prague from June 2016 t...
About 1–2% of European population are redheaded, meaning they synthesize more pheomelanin than eumelanin, the main melanin pigment in humans. Several mutations could be responsible for this phenotype. It has been suggested that corresponding mutations spread in Europe due to a founder effect shaped either by a relaxation of selection for dark, UV‐p...
Toxoplasmosis is a parasitic disease widespread in the temperate zone. The definitive hosts of Toxoplasma gondii, which causes the disease, are cats. All warm-blooded vertebrates, including humans, can be intermediate hosts. A person is usually infected by ingesting oocysts, e.g. by consuming along with vegetables some contaminated soil, by drinkin...
About 1-2% of European population are redhaired, meaning they synthesize more pheomelanin than eumelanin, the main melanin pigment. Several mutations could be responsible for this phenotype. It has been suggested that corresponding mutations spread in Europe due to a founder effect shaped either by a relaxation of selection for dark, UV-protective...
Toxoplasmosis affects about one third of human population worldwide. It has a wide range of effects on the health, immunity, behaviour, and both prenatal and postnatal outcomes of infected hosts, including humans. Among these effects, stage of infection-specific shifts in secondary sex ratio were described about ten years ago both in humans and in...
The results of previous studies overwhelmingly suggest that RhD positive heterozygotes express better health status than Rh positive homozygous, especially in RhD negative subjects. This also applies to pregnant women. According to the Trivers-Willard hypothesis, women in better physical condition should have a male-skewed sex ratio. The aim of the...
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 t...
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 imm...
Background: Maternal age, parity and fetal sex are each known to affect obstetric and birth outcomes. The objective of the present study was to investigate the influence of the combination of maternal age, parity and fetal sex on outcomes of pregnancies. The aim of the study was to analyze the influence of maternal age on perinatal outcomes in both...
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 immunocompete...
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 populati...
About 30-50% of the world human population are infected with the protozoan parasite Toxoplasma gondii (Nicolle et Manceaux, 1908). Latent toxoplasmosis has many specific behavioural and physiological effects on the human body and influences the course of pregnancy, including secondary sex ratio of children of infected mothers. It was suggested that...
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 (...
Background
Toxoplasmosis, one of the most common zoonotic diseases worldwide, can induce various hormonal and behavioural alterations in infected hosts, and its most common form, latent toxoplasmosis, influences the course of pregnancy. Autoimmune thyroid diseases (AITD) belong to the well-defined risk factors for adverse pregnancy outcomes. The ai...
Introduction: Latent toxoplasmosis, a zoonosis caused by protozoan Toxoplasma gondii, is the most widespread human parasitosis in developed countries (prevalence 2080%). Upon infection, T. gondii stays in human organism lifelong. It has been linked to several autoimmune diseases, including autoimmune thyroid disease (AITD). The aim of our study wa...
Toxoplasmosis, a zoonosis caused by a protozoan, Toxoplasma gondii, is probably the most widespread human parasitosis in developed countries. Pregnant women with latent toxoplasmosis have seemingly younger fetuses especially in the 16th week of gestation, which suggests that fetuses of Toxoplasma-infected mothers have slower rates of development in...
Cortisol, along with other hormones of hypothalamo-pituitary-adrenal axis, belongs to one of the main factors influencing psychological and pathognomic factors, intelligence, and memory.
The aim of our study was to review a large battery of psychological, performance, IQ and memory tests as to their relation with cortisol, testosterone and estrogen...
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 immunos...
RhD-positive subjects are protected against toxoplasmosis-associated impairment of psychomotor performance. Here we searched for RhD-positivity-associated maternal protection against the effects of toxoplasmosis.
In the present retrospective cohort study, we analysed data from 785 (139 RhD-negative) Toxoplasma-free and 194 (27 RhD-negative) Toxopla...
The sex ratio may be influenced by many factors, such as stress and immunosuppression, age of parents, parity and sex of preceding siblings. In animal systems, parasitism often changes the sex ratio of infected hosts, which can increase the probability of their transmission. The most common human protozoan parasite in developed countries, Toxoplasm...
The boy-to-girl ratio at birth (secondary sex ratio) is around 0.51 in most populations. The sex ratio varies between societies and may be influenced by many factors, such as stress and immunosuppression, age, primiparity, the sex of the preceding siblings and the socioeconomic status of the parents. As parasite infection affects many immunological...
The purpose of this study was to confirm that women with latent toxoplasmosis have developmentally younger fetuses at estimated pregnancy week 16 and to test four exclusive hypotheses that could explain the observed data.
In the present retrospective cohort study we analysed by the GLM (general linear model) method data from 730 Toxoplasma-free and...
Intracellular parasite Toxoplasma gondii (TG) is considered to be an infectious agent, which plays a role in the aetiology and pathogenesis of some cases of shizophrenia. TG infection-related cognitive dysfunction is considered as an element of vulnerability for the development of some schizophrenia subtypes. The hypothesis that links TG infection...