Intracellular Protozoan Toxoplasma Gondii Research Articles

Seroprevalence and Risk Factors of Toxoplasma gondii Infection of Cattle and Goats in Farms of Hunan Province, China.

Background: Toxoplasmosis is one of the most widespread foodborne parasitic zoonoses caused by the obligate intracellular protozoan Toxoplasma gondii. Although a number of studies have reported on the seroprevalence and risk factors of T. gondii infection in ruminants in China, information about T. gondii infection in cattle in Hunan province of China is not available. Material and Methods: Sera of 985 cattle and 1147 goats were examined for the presence of specific antibodies against T. gondii using the indirect hemagglutination test. Some risk factors related to the presence of cats, herd size, gender, age, and geographical origin were determined using a binary logistic regression. Results: Specific IgG against T. gondii were detected in 8.3% (82/985) and 13.3% (153/1147) of the cattle and goats, respectively. Based on statistical analysis, the presence of cats and gender were considered important risk factors for T. gondii infection in cattle and goats in the farms in this study (P < 0.05). Conclusion: Our results provide a baseline for future prevention and control of T. gondii infection in cattle and goats in Hunan province, subtropical China. This is the first report of T. gondii seroprevalence in cattle in Hunan province, China.

Prevalence of Toxoplasma gondii Antibodies and Risk Factors in Two Sympatric Invasive Carnivores (Procyon lotor and Nyctereutes procyonoides) from Zgorzelec County, Poland.

The intracellular protozoan Toxoplasma gondii is distributed worldwide and infects many species of warm-blooded animals. Most mammals, including humans, can serve as intermediate hosts. This pathogen, with its zoonotic potential, causes toxoplasmosis, a condition that can range from subclinical to fatal in humans. It is therefore important to assess the occurrence of the pathogen, even if only indirectly through the detection of antibodies. Epidemiological data on the seroprevalence in wild animals, including invasive species, are rare in Poland. Therefore, we tested 197 wild raccoons (Procyon lotor) and 89 raccoon dogs (Nyctereutes procyonoides) from Zgorzelec County, southwestern Poland, for the presence of antibodies. Samples were collected between January 2019 and December 2020 and analysed using a commercial indirect modified agglutination test (MAT, cut-off 1:25). The statistical analysis revealed significant differences in seroprevalence between the two predatory species. Of the 197 surveyed raccoons, 96 (48.73%; 95% confidence interval (CI): 41.73-55.73%) tested positive, while 25 of the 89 raccoon dogs (28.09%; 95% CI: 18.70-37.48%) were positive. Regarding risk factors, body weight and sex influenced the presence of T. gondii antibodies in both the species, with a higher likelihood of seropositivity among heavier animals and females, respectively. For raccoon dogs, juveniles were more likely to be seropositive than adults at a given weight. Our results suggest that T. gondii infection is widespread in the regional raccoon and raccoon dog populations, indicating a high level of parasite circulation in the environment.

Prevalencija infekcije parazitom Toxoplasma gondii u svetu i Srbiji

Toxoplasmosis is one of the most widespread parasitic diseases caused by an obligate intracellular protozoan Toxoplasma gondii. It is estimated that one-third of the human population is infected with this parasite. In immunocompetent subjects, the infection is mostly asymptomatic or is presented with flu-like symptoms, but in fetuses and immunocompromised patients, the infection may even be life-threatening. The prevalence of T. gondii infection varies among different countries of the world (0.5 - 87.7%) and within different regions of the same country. In Africa, the prevalence is the highest (20.8 - 87.7%), in Asia is the lowest (0.5 - 82.6%), while in Europe, the prevalence of toxoplasmosis ranges from low in the North to moderate in the South of the continent (8.2% - 59.0%). The worldwide decline in the prevalence of T. gondii infection has been sustained over the past few decades. In Serbia, the prevalence of toxoplasmosis tended to increase from the 1960s to the 1980s followed by a dramatic decline after that period, as in the entire Europe. The most prominent decline in the prevalence of T. gondii infection was recorded in the period from 1988 to 2007 in the population of women of reproductive age from 86% to 32.5%. The decreasing tendency of the prevalence of toxoplasmosis in Serbia remains continuous even after that period, further confirmed by the latest results of research conducted in 2017 - 2018 in the population of blood donors in Belgrade (20.5%) and in the general population of Vojvodina during the 2008 - 2021 period (20%). Despite the encouraging epidemiological data that indicate the trend of continuous decline in the prevalence of toxoplasmosis in the world and our country, it is still necessary to conduct additional research to identify specific risk factors that contribute to the decrease in the prevalence of T. gondii infection in the population.

An Overview of One Health Concept Focusing on Toxoplasmosis.

The "One Health" concept is a universal approach to sustainably balancing and optimizing the health of humans, animals, and ecosystems. This approach is based on the health of humans, domestic and wild animals, and plants in a wider environment in which self-renewable ecosystems exist, with essential characteristics of integration, unifying and holistic perspective. Toxoplasmosis, one of the most common zoonotic infections in both terrestrial and oceanic ecosystems in the world, is an ideal model disease for the "One Health" approach. Toxoplasmosis is a zoonotic disease caused by the obligate intracellular pathogen protozoan Toxoplasma gondii. In the life cycle of T. gondii, the definitive host is domestic cats and felines, and the intermediate hosts are all mammals (including humans), birds and reptiles. The infected cats have primary importance and play a crucial role in the contamination of habitats in the ecosystems with T. gondii oocysts. Thus, ecosystems with domestic cats and stray cats are contaminated with cat feces infected with T. gondii oocytes. T. gondii positivity has been scientifically demonstrated in all warm-blooded animals in terrestrial and aquatic habitats. The disease causes deaths and abortions in farm animals, resulting in great economic losses. However, the disease causes great problems in humans, especially pregnant women. During pregnancy, it may have effects such as congenital infections, lesions in the eye and brain of the fetus, premature birth, intrauterine growth retardation, fever, pneumonia, thrombocytopenia, ocular lesions, encephalitis, and abortion. The mechanism of death and abortion of the fetus in a pregnant woman infected with T. gondii occurs as a result of complete disruption of the maternal immune mechanism. The struggle against toxoplasmosis requires the universal collaboration and coordination of the World Organization for Animal Health, the World Health Organization and the World Food Organization in the "One Health" concept and integrative approaches of all responsible disciplines. Establishing universal environmental safety with the prevention and control of toxoplasmosis requires the annihilation of the feces of the infected cats using suitable techniques firstly. Then routinely, the monitoring and treatment of T. gondii positivity in cats, avoiding contact with contaminated foods and materials, and development of modern treatment and vaccine options. Particularly, mandatory monitoring or screening of T. gondii positivity during the pregnancy period in humans should be done. It would be beneficial to replace the French model, especially in the monitoring of disease in humans. In this article, the ecology of toxoplasmosis was reviewed at the base of the "One Health" concept.

Canine Toxoplasma Gondii and Distemper Virus Co-Infection in a Dog with Neuro-ophthalmologic Signs from Córdoba, Argentina

Toxoplasmosis is caused by the globally distributed parasitic intracellular protozoan Toxoplasma gondii (phylum Apicomplexa, family Sarcocystidae). Domestic cats and other felids are the definitive hosts.

Seroepidemiological study of Toxoplasma gondii in equids in different European countries.

Toxoplasmosis, caused by the obligate intracellular protozoan Toxoplasma gondii, is a worldwide parasitic zoonosis. A cross-sectional study was carried out to determine the exposure to T. gondii in equids in Europe. Serum samples from 1399 equids (1085 horses, 238 donkeys, and 76 mules/hinnies) bred in four European countries (Italy, Spain, United Kingdom [UK], and Ireland) were collected during the period of 2013-2021. The overall seroprevalence of T. gondii was 18.9% (95% Confidence Interval [CI]: 16.9-21.0) by using the modified agglutination test (MAT) at a cut-off of 1:25. Seropositivity by country was 27.1% in Italy, 16.6% in Spain, 12.0% in UK and 7.0% in Ireland. Anti-T. gondii antibodies were detected in 12.8% of the horses, 43.7% of the donkeys, and in 28.9% of the mules/hinnies. A Generalized Estimating Equation (GEE) analysis was carried out to study the associations between seropositivity and explanatory variables related to individuals, herds, and management measures on these herds, selected based on the bivariate analysis. The risk for being seropositive for T. gondii was 5.3 and 2.7 times higher in donkeys and mules/hinnies than in horses, respectively. In addition, significantly higher seropositivity was observed in horses from herds that used disinfectants less than once a week (13.9%; p=0.038, odds ratio [OR]=1.6; 95% CI: 1.03-2.62) compared with those from herds that performed weekly disinfection of the facilities (9.4%). This is the first large-scale seroepidemiological study on T. gondii comprising horses, donkeys, and mules/hinnies in Europe and the first report of T. gondii exposure in horses from Ireland and UK. We found a widespread distribution of T. gondii among equid populations in different European countries. The seroprevalence found in these species, especially in donkeys and mules/hinnies, highlights the potential risk of human infection through the consumption of their raw/undercooked milk or meat.

The Toxoplasma effector GRA28 promotes parasite dissemination by inducing dendritic cell-like migratory properties in infected macrophages

Upon pathogen detection, macrophages normally stay sessile in tissues while dendritic cells (DCs) migrate to secondary lymphoid tissues. The obligate intracellular protozoan Toxoplasma gondii exploits the trafficking of mononuclear phagocytes for dissemination via unclear mechanisms. We report that, upon T.gondii infection, macrophages initiate the expression of transcription factors normally attributed to DCs, upregulate CCR7 expression with a chemotactic response, and perform systemic migration when adoptively transferred into mice. We show that parasite effector GRA28, released by the MYR1 secretory pathway, cooperates with host chromatin remodelers in the host cell nucleus to drive the chemotactic migration of parasitized macrophages. During invivo challenge studies, bone marrow-derived macrophages infected with wild-type T.gondii outcompeted those challenged with MYR1- or GRA28-deficient strains in migrating and reaching secondary organs. This work reveals how an intracellular parasite hijacks chemotaxis in phagocytes and highlights a remarkable migratory plasticity in differentiated cells of the mononuclear phagocyte system.

4-Arylthiosemicarbazide Derivatives as Toxoplasmic Aromatic Amino Acid Hydroxylase Inhibitors and Anti-inflammatory Agents.

Approximately one-third of the human population is infected with the intracellular cosmopolitan protozoan Toxoplasma gondii (Tg), and a specific treatment for this parasite is still needed. Additionally, the increasing resistance of Tg to drugs has become a challenge for numerous research centers. The high selectivity of a compound toward the protozoan, along with low cytotoxicity toward the host cells, form the basis for further research, which aims at determining the molecular targets of the active compounds. Thiosemicarbazide derivatives are biologically active organic compounds. Previous studies on the initial preselection of 58 new 4-arylthiosemicarbazide derivatives in terms of their anti-Tg activity and selectivity made it possible to select two promising derivatives for further research. One of the important amino acids involved in the proliferation of Tg and the formation of parasitophorous vacuoles is tyrosine, which is converted by two unique aromatic amino acid hydroxylases to levodopa. Enzymatic studies with two derivatives (R: para-nitro and meta-iodo) and recombinant aromatic amino acid hydroxylase (AAHs) obtained in the E. coli expression system were performed, and the results indicated that toxoplasmic AAHs are a molecular target for 4-arylthiosemicarbazide derivatives. Moreover, the drug affinity responsive target stability assay also confirmed that the selected compounds bind to AAHs. Additionally, the anti-inflammatory activity of these derivatives was tested using THP1-Blue™ NF-κB reporter cells due to the similarity of the thiosemicarbazide scaffold to thiosemicarbazone, both of which are known NF-κB pathway inhibitors.

Toxoplasma gondii DNA methyltransferases regulate parasitic energy metabolism

The intracellular protozoan Toxoplasma gondii results in serious diseases such as encephalitis, and retinochoroiditis in immunocompromised patients. The interconversion between tachyzoites and bradyzoites under the host's immune pressure results in the interchange of acute infection and chronic infection. We previously reported two functional DNA methyltransferases (DNMT) in Toxoplasma gondii named TgDNMTa and TgDNMTb. In this research, proteomics analysis for T. gondii tachyzoites of ME49 WT, dnmta knockout (ME49-∆Tgdnmta), and dnmtb knockout (ME49-∆Tgdnmtb) strains, revealed 362 significantly regulated proteins for ME49-∆Tgdnmta, and 219 for ME49-∆Tgdnmtb, compared with the proteins of ME49 WT. TgDNMTa down regulated three glycolytic enzymes, one gluconeogenic enzyme and four pyruvate metabolic enzymes. Furthermore, TgDNMTb up regulated two proteins in the tricarboxylic acid (TCA) cycle. Glucose metabolic flux detection showed that TgDNMTa inhibited the glycolysis pathway, while TgDNMTb promoted the tricarboxylic acid (TCA) cycle so as to promote parasite's proliferation. These findings demonstrated that the functions of Toxoplasma gondii DNA methyltransferases extended beyond DNA methylation to the regulation of parasitic energy metabolism.

Towards an Integrated Approach for Monitoring Toxoplasmosis in Southern Italy.

Simple SummaryToxoplasmosis is a significant public health issue worldwide, caused by the intracellular protozoan Toxoplasma gondii. It has a heteroxenous life cycle in which felines act as definitive reservoirs and a wide range of warm-blooded animals, including humans, act as intermediate hosts. Due to the complex life cycle, monitoring, prevention and control of this parasite are very difficult. A thorough analysis of the epidemiology of T. gondii in humans, animals and food as well as the risk factors associated with the infection are needed to plan adequate control strategies in a given geographical area. Based on this, an integrated approach for monitoring toxoplasmosis was developed and conducted in an endemic area of southern Italy. The main tasks of this approach were based on the following strategies: parasitological and risk factor analysis for T. gondii in livestock farms, serological and molecular monitoring in meat-producing livestock at slaughterhouses, hospital discharge records (HDRs) analysis and outreach activities. The findings of this study confirmed the spread of T. gondii infection in southern Italy with high prevalence values in ruminants and the need of valid control strategies based on comprehensive and transdisciplinary actions according to the One Health approach.Toxoplasmosis is a widespread worldwide zoonotic infection caused by the intracellular protozoan Toxoplasma gondii. This protozoan infection is considered one of the most important food-borne parasitic zoonoses globally. Beyond its impact on public health, toxoplasmosis has also important veterinary implications, because it causes miscarriage or congenital malformations in livestock with negative economic impacts. An integrated monitoring programme aimed to deepen the epidemiological data on toxoplasmosis and to identify the risk factors that may favour T. gondii infections in animals and humans was conducted in an endemic area of southern Italy. The monitoring activities were based on the following tasks: (i) parasitological analysis and risk factors for T. gondii in livestock (sheep, goat, cattle and water buffalo) farms; (ii) serological and molecular monitoring at slaughterhouse in meat-producing livestock; (iii) analysis of hospital discharge records (HDRs); (iv) outreach activities (information, dissemination and health education) to farmers, vet practitioners and school-age children. The present study confirmed a very high seroprevalence of T. gondii infection in livestock farms (e.g., up to 93.1% in sheep farms) in southern Italy and highlighted the potentially significant public health risk in this area.

Integrin-dependent migratory switches regulate the translocation of Toxoplasma-infected dendritic cells across brain endothelial monolayers

Multiple cellular processes, such as immune responses and cancer cell metastasis, crucially depend on interconvertible migration modes. However, knowledge is scarce on how infectious agents impact the processes of cell adhesion and migration at restrictive biological barriers. In extracellular matrix, dendritic cells (DCs) infected by the obligate intracellular protozoan Toxoplasma gondii undergo mesenchymal-to-amoeboid transition (MAT) for rapid integrin-independent migration. Here, in a cellular model of the blood–brain barrier, we report that parasitised DCs adhere to polarised endothelium and shift to integrin-dependent motility, accompanied by elevated transendothelial migration (TEM). Upon contact with endothelium, parasitised DCs dramatically reduced velocities and adhered under both static and shear stress conditions, thereby obliterating the infection-induced amoeboid motility displayed in collagen matrix. The motility of adherent parasitised DCs on endothelial monolayers was restored by blockade of β1 and β2 integrins or ICAM-1, which conversely reduced motility on collagen-coated surfaces. Moreover, parasitised DCs exhibited enhanced translocation across highly polarised primary murine brain endothelial cell monolayers. Blockade of β1, β2 integrins, ICAM-1 and PECAM-1 reduced TEM frequencies. Finally, gene silencing of the pan-integrin-cytoskeleton linker talin (Tln1) or of β1 integrin (Itgb1) in primary DCs resulted in increased motility on endothelium and decreased TEM. Adding to the paradigms of leukocyte diapedesis, the findings provide novel insights in how an intracellular pathogen impacts the migratory plasticity of leukocytes in response to the cellular environment, to promote infection-related dissemination.

Immunogenicity and protection efficacy of enhanced fitness recombinant Salmonella Typhi monovalent and bivalent vaccine strains against acute toxoplasmosis

ABSTRACT The proficiency of Salmonella Typhi to induce cell-mediated immunity has allowed its exploitation as a live vector against the obligate intracellular protozoan Toxoplasma gondii. T. gondii vaccine research is of great medical value due to the lack of a suitable toxoplasmosis vaccine. In the present work, we integrated T. gondii antigen into a growth-dependent chromosome locus guaBA of S. Typhi CVD910 strain to form recombinant S. Typhi monovalent CVD910-SAG1 expressed T. gondii SAG1 antigen and monovalent CVD910-GRA2 expressed T. gondii GRA2 antigen. Furthermore, a low-copy stabilized recombinant plasmid encoding SAG1 antigen was transformed into CVD910-GRA2 to form bivalent CVD910-GS strain. An osmolarity-regulated promoter was also incorporated to control the gene transcription, whereas clyA export protein was included to translocate the antigen out of the cytoplasm. Both CVD910-GRA2 and CVD910-GS displayed healthy growth fitness and readily expressed the encoded T. gondii antigens. When administered in vivo, CVD910-GS successfully induced both humoral and cellular immunity in the immunized BALB/c mice, and extended mice survival against virulent T. gondii. In particular, the mice immunized with bivalent CVD910-GS presented the highest titers of IgG, percentages of CD4+ T, CD8+ T, B cells and memory T cells, and total IgG+ memory B cells as compared to the CVD910-GRA2 and control strains. The CVD910-GS group also generated mixed Th1/Th2 cytokine profile with secretions of IFN-ɣ, IL-2 and IL-10. This study demonstrated the importance of enhancing live vector fitness to sustain heterologous antigen expression for eliciting robust immune responses and providing effective protection against pathogen.

Devitalization of the immune mapped protein 1 undermines the intracellular proliferation of Toxoplasma gondii

The intracellular protozoan Toxoplasma gondii infects approximately one-third of the world's population as well as various animals, causing toxoplasmosis. However, there remains a need to define the functions of newly identified genes of T. gondii. In the present study, a novel molecule, immune mapped protein 1 of T. gondii (TgIMP1), was devitalized by CRISPR/Cas9 system to investigate the phenotypic changes of the parasite. We found that the virulence of ΔTgIMP1 knockout strain was reduced in comparison with wild-type GT1 tachyzoites, showing a statistically decreased plaque in HFF cells and a significantly prolonged survival period of mice (P < 0.05). Moreover, the data of phenotype analyses in vitro showed a different level of the intracellular proliferation and the subsequent egress between ΔTgIMP1 and wild-type GT1 strain (P < 0.05); while no statistically significant difference was detected during the process of attachment or invasion. These results suggested that TgIMP1 is closely associated with the intracellular proliferation of this parasite.

TOXOPLASMA GONDII STIMULATES THE BEHAVIOURAL CHANGES OF RODENTS: UPDATED EVIDENCE

In recent years, there have been an increased number of reports in the literatures on animal behavioural changeslinked with intracellular protozoan Toxoplasma gondii. Evidence for animal behavioural changes with Toxoplasmagondii infection comes from experimental tests on animal models such as mice and rats. These studies describethe important mechanisms of behavioural changes which involving neuromodulator and neurotransmitter level.Furthermore, behavioural changes also have been identified in human as well as animal models that may also playa role in development of schizophrenia in humans

Resveratrol as a Therapy to Restore Neurogliogenesis of Neural Progenitor Cells Infected by Toxoplasma gondii.

The intracellular protozoan Toxoplasma gondii may cause congenital toxoplasmosis and serious brain damage in fetus. However, the underlying mechanism of neuropathogenesis in brain toxoplasmosis remains unclear. For this study, neural progenitor cells (NPCs) were obtained from embryo telencephalons (embryonic day 13) and induced to proliferation in the presence of growth factors (GFs). For gathering insights into the biological effects of resveratrol (RSV) on neurogenesis, this study aimed to investigate effects of RSV concentrations (0.1 to 100μM) on proliferation, migration and differentiation of NPCs infected by T. gondii. T. gondii infection increased the presence of cells in Sub G1 phase, reducing the global frequency of undifferentiated cells in S and G2/M phases of cell cycle and reduced cell viability/mithochondrial activity of infected NPCs. Moreover T. gondii stimulated neural migration and gliogenesis during neutral differentation. However, the treatment with RSV stimulated cell proliferation, restored cellular viability of infected NPCs and exerted an inhibitory effect on gliogenesis of infected NPCs favorecing neuronal maturation during toxoplasmosis infection. Thus, we have successfully to demonstrated that RSV is promising as therapeutic for congenital toxoplasmosis.

Congenital central toxoplasmic chorioretinitis - case study.

Congenital toxoplasmosis is a globally spread infectious disease caused by transplacental transmission of an intracellular parasitic protozoan Toxoplasma gondii. The infection can cause serious multi-organ complications, and in the case of vertical transmission, can lead up to fetal death - depending on the stage of pregnancy at the time of infection and the overall condition of the mothers immune system. Chorioretinitis, hydrocephalus and intracranial calcifications are a typical triad of symptoms associated with the disease. Toxoplasmic chorioretinitis in particular is the most common ocular manifestation. If the central retina is affected, it can cause a severe impairment of central visual acuity or lead up to blindness in the child. Prenatal screening of this disease is presently voluntary in the Czech Republic. This article reports on a case study of a toxoplasmic chorioretinitis in a newborn child observed from the active stage and the development of the affected retina over time. Further is also reported on the diagnostics and the treatment of multi-organ complications which occurred in this patient. Ophthalmologic examination was performed after diagnosis of hydrocephalus, which revealed severe changes of retina. Hydrocephalus was then properly treated. An overview of the diagnostic and therapeutic methods and the screening options available in the Czech Republic compare with other countries is also presented in the report. Key words: congenital toxoplasmosis, chorioretinitis, multi-organ complications, screening, hydrocephalus.

Immunization With a DNA Vaccine Cocktail Encoding TgPF, TgROP16, TgROP18, TgMIC6, and TgCDPK3 Genes Protects Mice Against Chronic Toxoplasmosis.

Toxoplasmosis is a zoonotic disease caused by the intracellular protozoan Toxoplasma gondii; and a major source of infection in humans is via ingestion of T. gondii tissue cysts. Ultimately, the goal of anti-toxoplasmosis vaccines is to elicit a sustainable immune response, capable of preventing formation of the parasite tissue cysts—or, at least, to restrain its growth. In this study, we formulated a cocktail DNA vaccine and investigated its immunologic efficacy as a protection against the establishment of T. gondii cysts in the mouse brain. This multicomponent DNA vaccine, encoded the TgPF, TgROP16, TgROP18, TgMIC6, and TgCDPK3 genes, which play key roles in the pathogenesis of T. gondii infection. Results showed that mice immunized via intramuscular injection three times, at 2-week intervals with this multicomponent DNA vaccine, mounted a strong humoral and cellular immune response, indicated by significantly high levels of total IgG, CD4+ and CD8+ T lymphocytes, and antigen-specific lymphocyte proliferation when compared with non-immunized mice. Immunization also induced a mixed Th1/Th2 response, with a slightly elevated IgG2a to IgG1 ratio. The increased production of proinflammatory cytokines gamma-interferon, interleukin-2, and interleukin-12 (p < 0.0001) correlated with increased expression of p65/RelA and T-bet genes of the NF-κB pathway. However, no significant difference was detected in level of interleukin-4 (p > 0.05). The number of brain cysts in immunized mice was significantly less than those in non-immunized mice (643.33 ± 89.63 versus 3,244.33 ± 96.42, p < 0.0001), resulting in an 80.22% reduction in the parasite cyst burden. These findings indicate that a multicomponent DNA vaccine, encoding TgPF, TgROP16, TgROP18, TgMIC6, and TgCDPK3 genes, shows promise as an immunization strategy against chronic toxoplasmosis in mice, and calls for a further evaluation in food-producing animals.

Age-related prevalence of toxoplasmosis among pregnant women in Hatay: Estimation depending on model

Toxoplasmosis, caused by the obligate intracellular protozoan Toxoplasma gondii, is a common parasitic infection affecting approximately one-third of the world population. T.gondii infections are usually acquired by ingesting raw or insufficiently cooked meat and from unwashed fruits and vegetables contaminated with soil or water with cat feces. Primary infection acquired during pregnancy can cause severe congenital abnormalities in the fetus such as neurologic and ocular malformations, abortion, or stillbirth according to the degree of infection. The aim of this study was to estimate the prevalence and rate of seroconversion of T.gondii IgG antibodies in a selected population of pregnant women in Hatay by using a mathematical model. T.gondii-specific serological screening test results of 11.564 pregnant women who have attended the Private Antakya Mosaic Obstetrics and Gynecology Hospital between 01.04.2009 and 31.04.2016 were analysed in the study. The prevalence of T.gondii-specific IgG antibodies in the studied population were found as 48.70% (95% CI, 0.48-0.50). The prevalence of T.gondii-specific IgG antibodies were increased linearly with age in our study population. The relationship between age and prevalence was statistically significant (p< 0.001). The age-specific rate of seroconversion was estimated as 0.8% for T.gondii infection in pregnant women. It was observed that the rate of T.gondii-specific IgG antibodies decreased from 55.12% (95% Cl, 0.52-0.57) detected in 2009 to 42.22% (95% Cl, 0.37-0.46) in 2016. The estimated number of cases carrying the risk of primer T.gondii infection was calculated as 69 in the study population. Our results have suggested that the prevalence of T.gondii-specific antibodies is high among pregnant women in Hatay. Early maternal diagnosis and treatment methods may reduce the risk of transplacental transmission during pregnancy. The on time diagnosis can only be achieved with prenatal serological screening. The knowledge of the incidence and prevalence of toxoplasma infection in pregnant women plays a crucial role in estimating the burden of the disease and evaluating the effectiveness of the public health protection policies including screening programmes. Expanding of training activities, drawing attention to hygiene, taking nutritional precautions and increasing awareness of toxoplasmosis in pregnant women are important to prevent congenital toxoplasmosis or minimize the disease.

A Report of Two Cases with Different Clinical Presentation of Cerebral Toxoplasmosis in HIV-Infected Bulgarian Patients

Toxoplasmosis is a disease caused by an obligate intracellular protozoan Toxoplasma gondii. In immunocompetent adults, infection can occur subclinically, or with lymphadenitis. In HIV-infected individuals with severe immune suppression, Toxoplasma gondii can cause severe disease with invasion of the gray and white matter of the brain, the retina, the lungs, the heart and the skeletal muscles. Toxoplasmosis is the most common opportunistic infection of the central nervous system in patients with acquired immunodeficiency syndrome (AIDS). The clinical presentation of cerebral toxoplasmosis in the majority of these patients includes headaches, focal neurological deficits, and seizures. In this article, we report two cases with different presentation of cerebral toxoplasmosis in the setting of an HIV infection.

A Novel Secreted Protein, MYR1, Is Central to Toxoplasma's Manipulation of Host Cells.

ABSTRACTThe intracellular protozoan Toxoplasma gondii dramatically reprograms the transcriptome of host cells it infects, including substantially up-regulating the host oncogene c-myc. By applying a flow cytometry-based selection to infected mouse cells expressing green fluorescent protein fused to c-Myc (c-Myc–GFP), we isolated mutant tachyzoites defective in this host c-Myc up-regulation. Whole-genome sequencing of three such mutants led to the identification of MYR1 (Myc regulation 1; TGGT1_254470) as essential for c-Myc induction. MYR1 is a secreted protein that requires TgASP5 to be cleaved into two stable portions, both of which are ultimately found within the parasitophorous vacuole and at the parasitophorous vacuole membrane. Deletion of MYR1 revealed that in addition to its requirement for c-Myc up-regulation, the MYR1 protein is needed for the ability of Toxoplasma tachyzoites to modulate several other important host pathways, including those mediated by the dense granule effectors GRA16 and GRA24. This result, combined with its location at the parasitophorous vacuole membrane, suggested that MYR1 might be a component of the machinery that translocates Toxoplasma effectors from the parasitophorous vacuole into the host cytosol. Support for this possibility was obtained by showing that transit of GRA24 to the host nucleus is indeed MYR1-dependent. As predicted by this pleiotropic phenotype, parasites deficient in MYR1 were found to be severely attenuated in a mouse model of infection. We conclude, therefore, that MYR1 is a novel protein that plays a critical role in how Toxoplasma delivers effector proteins to the infected host cell and that this is crucial to virulence.