Blood Groups in Man By Dr. R. R. Race and Dr. Ruth Sanger. Pp. xv + 290. (Oxford: Blackwell Scientific Publications, Ltd., 1950.) 30s. net.

Human Blood Groups

OFFARM 123 E reservorio principal de Toxoplasma gondii es el gato doméstico (Felis catus), que por medio de los ooquistes que elimina con las heces, disemina la infección en el medio ambiente pudiendo transmitirla a multitud de animales, al hombre o incluso a pájaros y peces. La infección causada por este parásito pasa, en el hombre sano, casi inadvertida, pero no sucede lo mismo en individuos inmunodeprimidos en los que puede llegar a provocar la muerte. También el contraer la toxoplasmosis durante el embarazo entraña para la mujer, y principalmente para su feto, daños que pueden ser fatales pudiendo ocasionar abortos espontáneos o daños irreversibles en el sistema nervioso central del neonato. A pesar de los riesgos tan elevados que supone el contraer la toxoplasmosis para estos grupos y de que un individuo se pueda infectar después de una trasfusión sanguínea, ésta no es una enfermedad de declaración obligatoria.

돼지의 Toxoplasmosis의 진료

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.

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Toxoplasmosis – A Global Threat. Correlation of Latent Toxoplasmosis with Specific Disease Burden in a Set of 88 Countries

The highly prevalent parasite Toxoplasma gondii manipulates its host's behavior. In infected rodents, the behavioral changes increase the likelihood that the parasite will be transmitted back to its definitive cat host, an essential step in completion of the parasite's life cycle. The mechanism(s) responsible for behavioral changes in the host is unknown but two lines of published evidence suggest that the parasite alters neurotransmitter signal transduction: the disruption of the parasite-induced behavioral changes with medications used to treat psychiatric disease (specifically dopamine antagonists) and identification of a tyrosine hydroxylase encoded in the parasite genome. In this study, infection of mammalian dopaminergic cells with T. gondii enhanced the levels of K+-induced release of dopamine several-fold, with a direct correlation between the number of infected cells and the quantity of dopamine released. Immunostaining brain sections of infected mice with dopamine antibody showed intense staining of encysted parasites. Based on these analyses, T. gondii orchestrates a significant increase in dopamine metabolism in neural cells. Tyrosine hydroxylase, the rate-limiting enzyme for dopamine synthesis, was also found in intracellular tissue cysts in brain tissue with antibodies specific for the parasite-encoded tyrosine hydroxylase. These observations provide a mechanism for parasite-induced behavioral changes. The observed effects on dopamine metabolism could also be relevant in interpreting reports of psychobehavioral changes in toxoplasmosis-infected humans.

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The Neurotropic Parasite Toxoplasma Gondii Increases Dopamine Metabolism

Objective
To perform a meta-analysis on studies reporting prevalence of Toxoplasma gondii (T. gondii) infection in any psychiatric disorder compared with healthy controls. Our secondary objective was to analyze factors possibly moderating heterogeneity.

Method
A systematic search was performed to identify studies into T. gondii infection for all major psychiatric disorders versus healthy controls. Methodological quality, publication bias, and possible moderators were assessed.

Results
A total of 2866 citations were retrieved and 50 studies finally included. Significant odds ratios (ORs) with IgG antibodies were found in schizophrenia (OR 1.81, P < 0.00001), bipolar disorder (OR 1.52, P = 0.02), obsessive–compulsive disorder (OR 3.4, P < 0.001), and addiction (OR 1.91, P < 0.00001), but not for major depression (OR 1.21, P = 0.28). Exploration of the association between T. gondii and schizophrenia yielded a significant effect of seropositivity before onset and serointensity, but not IgM antibodies or gender. The amplitude of the OR was influenced by region and general seroprevalence. Moderators together accounted for 56% of the observed variance in study effects. After controlling for publication bias, the adjusted OR (1.43) in schizophrenia remained significant.

Conclusion
These findings suggest that T. gondii infection is associated with several psychiatric disorders and that in schizophrenia reactivation of latent T. gondii infection may occur.

Beyond the association. Toxoplasma gondii in schizophrenia, bipolar disorder, and addiction: systematic review and meta‐analysis

Toxoplasma gondii, a cosmopolitan protozoan parasite, is known to induce behavioural alterations in rodents and may exert an effect on human personality and behaviour. The mechanism of parasite-induced alterations in host behaviour has not been described, but it was hypothesized that development of Toxoplasma tissue cysts in the brain could affect the dopaminergic neuromodulatory system. In this study, we tested the effect of latent Toxoplasma infection on mouse behaviour associated with activity of the dopaminergic system, i.e. locomotion in a novel environment and exploration test. Additionally, we examined the behavioural response of Toxoplasma-infected mice to a selective dopamine uptake inhibitor, GBR 12909. In both genders, Toxoplasma infection decreased locomotion in the open field. Infected females displayed an increased level of exploration in the holeboard test. GBR 12909 induced suppression in holeboard-exploration in the infected males, but had an opposite effect on the controls. These results suggest an association between Toxoplasma gondii infection and changes in the dopaminergic neuromodulatory system.

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The role of dopamine in Toxoplasma-induced behavioural alterations in mice: an ethological and ethopharmacological study

Gender differences in behavioural changes induced by latent toxoplasmosis

The RhD protein which is the RHD gene product and a major component of the Rh blood group system carries the strongest blood group immunogen, the D-antigen. This antigen is absent in a significant minority of the human population (RhD-negatives) due to RHD deletion or alternation. The origin and persistence of this RhD polymorphism is an old evolutionary enigma. Before the advent of modern medicine, the carriers of the rarer allele (e.g. RhD-negative women in the population of RhD-positives or RhD-positive men in the population of RhD-negatives) were at a disadvantage as some of their children (RhD-positive children born to pre-immunized RhD-negative mothers) were at a higher risk of foetal or newborn death or health impairment from haemolytic disease. Therefore, the RhD-polymorphism should be unstable, unless the disadvantage of carriers of the locally less abundant allele is counterbalanced by, for example, higher viability of the heterozygotes. Here we demonstrated for the first time that among Toxoplasma-free subjects the RhD-negative men had faster reaction times than Rh-positive subjects and showed that heterozygous men with both the RhD plus and RhD minus alleles were protected against prolongation of reaction times caused by infection with the common protozoan parasite Toxoplasma gondii. Our results suggest that the balancing selection favouring heterozygotes could explain the origin and stability of the RhD polymorphism. Moreover, an unequal prevalence of toxoplasmosis in different countries could explain pronounced differences in frequencies of RhD-negative phenotype in geographically distinct populations.

/pdf/toxoplasma-and-reaction-time-role-of-toxoplasmosis-in-the-3nqdsa29ze.pdf

Toxoplasma and reaction time: role of toxoplasmosis in the origin, preservation and geographical distribution of Rh blood group polymorphism

OBJECTIVES: Toxoplasma gondii, a parasitic protozoan, infects about 30-60% of people worldwide Toxoplasma is known to induce behavioral changes and an increase of dopamine in mice The presence of anti- Toxoplasma antibodies (latent toxoplasmosis) is also a risk factor for schizophrenia Latent toxoplasmosis in men (male soldiers) is associated with lower novelty seeking As the novelty seek- ing is supposed to negatively correlate with level of dopamine, the observed effect was interpreted as indirect evidence of increased dopamine levels in subjects with toxoplasmosis However, it is also possible that the observed effect was caused by association of both novelty seeking and Toxoplasma infection with a third factor, eg size of place of residence METHODS: Personality profile of 290 blood donors (205 men and 85 women) were measured by Cloninger's TCI (Temperament and Character Inventory) and their blood samples were assayed for the presence of anti-Toxoplasma antibodies Dif- ference between Toxoplasma-infected and Toxoplasma-free subjects was tested with ANCOVA method with gender, size of place of residence, and age as covari- ates RESULTS: The present analysis revealed that lower novelty seeking was associ - ated with latent toxoplasmosis both in men and women The effect of infection on novelty seeking remained significant even after adjustment for size of place of residence (p<00�) CONCLUSION: Decreased novelty seeking in Toxoplasma-infected subjects have been already confirmed in three independent populations (male soldiers and male and female blood donors) These findings suggest that the local inflamma - tion-induced increase in dopamine in the brain of infected subjects can represent a missing link between toxoplasmosis and schizophrenia

/pdf/decreased-level-of-novelty-seeking-in-blood-donors-infected-4b7uqeqdci.pdf

Decreased level of novelty seeking in blood donors infected with Toxoplasma.

Toxoplasma is parasite of cats that uses any warm-blooded animals as intermediate hosts. It is known to induce shifts in behavior, physiology and even morphology of its intermediate hosts, including humans. The lower second to fourth digit ratio (2D:4D ratio) in infected man and women, and higher height in infected man suggest that sex steroid hormones like testosterone could play a role in these shifts. Here, we searched for another indirect indication for a higher postnatal testosterone level, i.e. increased perceived dominance and masculinity in infected men. We showed portrait pictures of 89 male students of which 18 were Toxoplasma-infected to 109 female students. When we statistically corrected for age, men with latent toxoplasmosis were perceived as more dominant (p=0.009) and masculine (p=0.052). These results support the idea that the higher level of testosterone could be responsible for at least some of the toxoplasmosis-associated shifts in human and animal behavior.

Higher perceived dominance in Toxoplasma infected men : a new evidence for role of increased Level of testosterone in toxoplasmosis-associated changes in human behavior

A. Skallová

Papers

The role of dopamine in Toxoplasma-induced behavioural alterations in mice: an ethological and ethopharmacological study

Gender differences in behavioural changes induced by latent toxoplasmosis

Toxoplasma and reaction time: role of toxoplasmosis in the origin, preservation and geographical distribution of Rh blood group polymorphism

Decreased level of novelty seeking in blood donors infected with Toxoplasma.

Higher perceived dominance in Toxoplasma infected men : a new evidence for role of increased Level of testosterone in toxoplasmosis-associated changes in human behavior