Toxoplasma gondii: transmission, diagnosis and prevention

A mechanistic study of Toxoplasma gondii ROP18 inhibiting differentiation of C17.2 neural stem cells

Background

Congenital infection of Toxoplasma gondii is an important factor causing birth defects. The neural stem cells (NSCs) are found to be one of the target cells for the parasite during development of the brain. As a key virulence factor of the parasite that hijacks host cellular functions, ROP18 has been demonstrated to mediate the inhibition of host innate and adaptive immune responses through specific binding different host immunity related molecules. However, its pathogenic actions in NSCs remain elusive.

Results

In the present study, ROP18 recombinant adenovirus (Ad-ROP18) was constructed and used to infect C17.2 NSCs. After 3d- or 5d–culture in differentiation medium, the differentiation of C17.2 NSCs and the activity of the Wnt/β-catenin signaling pathway were detected. The results showed that the protein level of βIII-tubulin, a marker of neurons, in the Ad-ROP18-transfected C17.2 NSCs was significantly decreased, indicating that the differentiation of C17.2 NSCs was inhibited by the ROP18. The β-catenin level in the Ad-ROP18-transfected C17.2 NSCs was found to be lower than that in the Ad group. Also, neurogenin1 (Ngn1) and neurogenin2 (Ngn2) were downregulated significantly (P < 0.05) in the Ad-ROP18-transfected C17.2 NSCs compared to the Ad group. Accordingly, the TOP flash/FOP flash dual-luciferase report system showed that the transfection of Ad-ROP18 decreased the Wnt/β-catenin pathway activity in the C17.2 NSCs.

Conclusions

The inhibition effect of the ROP18 from T. gondii (TgROP18) on the neuronal differentiation of C17.2 NSCs was at least partly mediated through inhibiting the activity of the Wnt/β-catenin signaling pathway, eventually resulting in the downregulation of Ngn1 and Ngn2. The findings help to better understand potential mechanisms of brain pathology induced by TgROP18.

Ablation of an Ovarian Tumor Family Deubiquitinase Exposes the Underlying Regulation Governing the Plasticity of Cell Cycle Progression in Toxoplasma gondii

The Toxoplasma genome encodes the capacity for distinct architectures underlying cell cycle progression in a life cycle stage-dependent manner. Replication in intermediate hosts occurs by endodyogeny, whereas a hybrid of schizogony and endopolygeny occurs in the gut of the definitive feline host. Here, we characterize the consequence of the loss of a cell cycle-regulated ovarian tumor (OTU family) deubiquitinase, OTUD3A of Toxoplasma gondii (TgOTUD3A; TGGT1_258780), in T. gondii tachyzoites. Rather than the mutation being detrimental, mutant parasites exhibited a fitness advantage, outcompeting the wild type. This phenotype was due to roughly one-third of TgOTUD3A-knockout (TgOTUD3A-KO) tachyzoites exhibiting deviations from endodyogeny by employing replication strategies that produced 3, 4, or 5 viable progeny within a gravid mother instead of the usual 2. We established the mechanistic basis underlying these altered replication strategies to be a dysregulation of centrosome duplication, causing a transient loss of stoichiometry between the inner and outer cores that resulted in a failure to terminate S phase at the attainment of 2N ploidy and/or the decoupling of mitosis and cytokinesis. The resulting dysregulation manifested as deviations in the normal transitions from S phase to mitosis (S/M) (endopolygeny-like) or M phase to cytokinesis (M/C) (schizogony-like). Notably, these imbalances are corrected prior to cytokinesis, resulting in the generation of normal progeny. Our findings suggest that decisions regarding the utilization of specific cell cycle architectures are controlled by a ubiquitin-mediated mechanism that is dependent on the absolute threshold levels of an as-yet-unknown target(s). Analysis of the TgOTUD3A-KO mutant provides new insights into mechanisms underlying the plasticity of apicomplexan cell cycle architecture.

Replication by Toxoplasma gondii can occur by 3 distinct cell cycle architectures. Endodyogeny is used by asexual stages, while a hybrid of schizogony and endopolygeny is used by merozoites in the definitive feline host. Here, we establish that the disruption of an ovarian-tumor (OTU) family deubiquitinase, TgOTUD3A, in tachyzoites results in dysregulation of the mechanism controlling the selection of replication strategy in a subset of parasites. The mechanistic basis for these altered cell cycles lies in the unique biology of the bipartite centrosome that is associated with the transient loss of stoichiometry between the inner and outer centrosome cores in the TgOTUD3A-KO mutant. This highlights the importance of ubiquitin-mediated regulation in the transition from the nuclear to the budding phases of the cell cycle and provides new mechanistic insights into the regulation of the organization of the apicomplexan cell cycle.

Toxoplasma gondii RON4 binds to heparan sulfate on the host cell surface

Toxoplasma gondii rhoptry neck protein 4 (TgRON4) is a component of the moving junction, a key structure for host cell invasion. We previously showed that host cellular β-tubulin is a binding partner of TgRON4 in the invasion process. Here, to identify other binding partners of TgRON4 in the host cell, we examined the binding of TgRON4 to components of the host cell surface. TgRON4 binds to various mammalian cells, but this binding disappeared in glycosaminoglycan- and heparan sulfate-deficient CHO cells and after heparitinase treatment of mammalian cells. The C-terminal half of TgRON4 showed relatively strong binding to cells and heparin agarose. A glycoarray assay indicated that TgRON4 binds to heparin and modified heparin derivatives. Immunoprecipitation of T. gondii-infected CHO cell lysates showed that TgRON4 interacts with glypican 1 during Toxoplasma invasion. This interaction suggests a role for heparan sulfate in parasite invasion.

Knowledge and Practices of Toxoplasmosis among Clinical Laboratory Professionals: A Cross-Sectional Study in Durango, Mexico

Background: The aim of this study was to determine the level of knowledge and practices about toxoplasmosis in a sample of clinical laboratory professionals in Mexico. Methods: 192 clinical laboratory professionals were surveyed. They were asked about (1) Toxoplasma gondii; (2) clinical manifestations, diagnosis, treatment, and epidemiology of toxoplasmosis; and (3) their practices with respect to toxoplasmosis. Results: The range of animals infected by T. gondii was known by 44.8% of participants. Clinical aspects of toxoplasmosis were known by up to 44.3% of subjects. Correct answers about the interpretation of serological markers of T. gondii infection were provided by up to 32.8% of participants. A minority (32.2%) of participants knew about a high number of false positive results of anti-T. gondii IgM antibody tests. Most participants (90.1%) did not know what the anti-T. gondii IgG avidity test was. Up to 55.7% of participants provided incorrect answers about the interpretation of serology tests for the treatment of pregnant women. Common routes of T. gondii infection were known by <15% of participants. Most (84.4%) participants had not performed tests for detection T. gondii infection. Conclusions: Results indicate incomplete knowledge of T. gondii infection and toxoplasmosis and a limited practice of laboratory tests among the professionals surveyed.

Feline Toxoplasmosis: Tumor Necrosis Factor, Nitric Oxide, and Free Radicals in Seropositive Cats

Toxoplasma gondii is a cosmopolitan protozoan that causes disease in several species, including humans. In cats, these infections are usually asymptomatic, but in other species they can lead to high levels of inflammatory and cell damage markers, causing cellular damage. Therefore, the aim of this study was to measure levels of tumor necrosis factor (TNF-α), reactive oxygen species (ROS), and nitric oxide (nitrite/nitrate-NO_x) in the serum of cats seropositive for T. gondii. Initially, we investigated the presence of antibodies against T. gondii in cats in the city of Concordia, Santa Catarina, Brazil, with the use of indirect immunofluorescence (IFA), and found 30 cats seropositive for T. gondii and 30 seronegative cats. In this study, seropositive cats showed higher levels of TNF-α, ROS, and NO_x compared to seronegative cats. Although cats do not show clinical signs of disease, constant inflammatory response can cause cell damage, which over time may adversely affect the animal.

Toxoplasma gondii tachyzoite-extract acts as a potent immunomodulator against allergic sensitization and airway inflammation

Epidemiological and experimental studies have shown an inverse relationship between infections with certain parasites and a reduced incidence of allergic diseases. We and others have shown that infection with Toxoplasma gondii prevents the development of allergy in mice. To establish whether this beneficial effect could be recapitulated by soluble products of this parasite, we tested an extract derived from T. gondii tachyzoites. Immunization of BALB/c mice with tachyzoites lysate antigen (TLA) elicited mixed Th1/Th2 responses. When TLA was applied together with the sensitizing ovalbumin (OVA), the development of allergic airway inflammation was reduced, with decreased airway hyperresponsiveness associated with reduced peribronchial and perivascular cellular infiltration, reduced production of OVA-specific Th2 cytokines in lungs and spleens and reduced levels of serum OVA-specific IgG1 as well as IgE-dependent basophil degranulation. Of note, TLA retained its immunomodulatory properties, inducing high levels of IL-6, TNFα, IL-10 and IL-12p70 in bone marrow-derived dendritic cells after heat-inactivation or proteinase K-treatment for disruption of proteins, but not after sodium metaperiodate-treatment that degrades carbohydrate structures, suggesting that carbohydrates may play a role in immunomodulatory properties of TLA. Here we show that extracts derived from parasites may replicate the benefits of parasitic infection, offering new therapies for immune-mediated disorders.

A seroepidemiological survey of Toxoplasma gondii infection in referred dogs to Veterinary Hospital of Ahvaz, Iran

Toxoplasma gondii is an intracellular protozoan parasite, which is the cause of toxoplasmosis and can infect a wide variety of warm-blooded animals, including dogs and humans. The present study evaluated the seroprevalence of T. gondii infection in pet dogs in Ahvaz, southwest city of Iran, and investigated the related possible risk factors. A total of 180 serum samples were collected from dogs referred to Veterinary Hospital of Ahvaz. The samples were then tested by indirect enzyme-linked immunosorbent assay. The prevalence of T. gondii antibodies were 46.67%. Logistic regression and chi square tests were used for evaluating of risk factors. The positivity increased statistically significantly with dog’s gender (56% females and 39% males, P = 0.001), age (18% in <2 years old, 96% in ≥4 years old, P = 0.001) and place of living (47% outdoor dogs 38% house hold dogs, P = 0.025). However, no statistically significant association was found with dogs’ breed, deworming, food ingestion or contact with cats. Overall, the results showed a relatively high seroprevalence of T. gondii infection in dogs in southwest Iran (Ahvaz) and proved association of T. gondii prevalence rates with the dog’s age, gender and place of living.

Modulators of 14-3-3 Protein-Protein Interactions

Direct interactions between proteins are essential for the regulation of their functions in biological pathways. Targeting the complex network of protein–protein interactions (PPIs) has now been widely recognized as an attractive means to therapeutically intervene in disease states. Even though this is a challenging endeavor and PPIs have long been regarded as “undruggable” targets, the last two decades have seen an increasing number of successful examples of PPI modulators, resulting in growing interest in this field. PPI modulation requires novel approaches and the integrated efforts of multiple disciplines to be a fruitful strategy. This perspective focuses on the hub-protein 14-3-3, which has several hundred identified protein interaction partners, and is therefore involved in a wide range of cellular processes and diseases. Here, we aim to provide an integrated overview of the approaches explored for the modulation of 14-3-3 PPIs and review the examples resulting from these efforts in both inhibiting and stabilizing specific 14-3-3 protein complexes by small molecules, peptide mimetics, and natural products.

The P2X7 Receptor Mediates Toxoplasma gondii Control in Macrophages through Canonical NLRP3 Inflammasome Activation and Reactive Oxygen Species Production

Toxoplasma gondii (T. gondii) is the protozoan parasite that causes toxoplasmosis, a potentially fatal disease to immunocompromised patients, and which affects approximately 30% of the world’s population. Previously, we showed that purinergic signaling via the P2X7 receptor contributes to T. gondii elimination in macrophages, through reactive oxygen species (ROS) production and lysosome fusion with the parasitophorous vacuole. Moreover, we demonstrated that P2X7 receptor activation promotes the production of anti-parasitic pro-inflammatory cytokines during early T. gondii infection in vivo. However, the cascade of signaling events that leads to parasite elimination via P2X7 receptor activation remained to be elucidated. Here, we investigated the cellular pathways involved in T. gondii elimination triggered by P2X7 receptor signaling, during early infection in macrophages. We focused on the potential role of the inflammasome, a protein complex that can be co-activated by the P2X7 receptor, and which is involved in the host immune defense against T. gondii infection. Using peritoneal and bone marrow-derived macrophages from knockout mice deficient for inflammasome components (NLRP3^−/−, Caspase-1/11^−/−, Caspase-11^−/−), we show that the control of T. gondii infection via P2X7 receptor activation by extracellular ATP (eATP) depends on the canonical inflammasome effector caspase-1, but not on caspase-11 (a non-canonical inflammasome effector). Parasite elimination via P2X7 receptor and inflammasome activation was also dependent on ROS generation and pannexin-1 channel. Treatment with eATP increased IL-1β secretion from infected macrophages, and this effect was dependent on the canonical NLRP3 inflammasome. Finally, treatment with recombinant IL-1β promoted parasite elimination via mitochondrial ROS generation (as assessed using Mito-TEMPO). Together, our results support a model where P2X7 receptor activation by eATP inhibits T. gondii growth in macrophages by triggering NADPH-oxidase-dependent ROS production, and also by activating a canonical NLRP3 inflammasome, which increases IL-1β production (via caspase-1 activity), leading to mitochondrial ROS generation.

Ocular Lesions in Congenital Toxoplasmosis in Santa Isabel do Ivaí, Paraná, Brazil

We verified clinical and psychopedagogic aspects of congenital cases with ocular sequelae, 13 years after toxoplasmosis outbreak in Santa Isabel do Ivaí, and current seroprevalence of this zoonosis in pregnant women. Audiologic and ophthalmologic evaluations were performed in congenital cases, in addition to collection of clinical and psychopedagogic data. In pregnant women, current seroprevalence was observed. Among affected teenagers, 2 of 5 are behind in school grade, and 4 of 5 reported learning difficulties, requiring psychopedagogic monitoring, as well as ocular complaints. We observed predominance of small, scarred, dispersed, type II chorioretinal lesions (hypopigmented halo and hyperpigmented central area), and 1 case of ocular relapse. All patients presented normal audiologic assessment. Among 131 pregnant women, 62 (47.3%) were seronegative and 39 (29.8%) were IgG reactive. Only 1 reported acquiring infection during the outbreak. This is one of the few studies in Brazil showing the outcome of congenital toxoplasmosis, a decade after infection, in one of the world's largest outbreaks.

CCR5 Is Involved in Interruption of Pregnancy in Mice Infected with Toxoplasma gondii during Early Pregnancy

Toxoplasmosis can cause abortion in pregnant humans and other animals; however, the mechanism of abortion remains unknown. C-C chemokine receptor type 5 (CCR5) is essential for host defense against Toxoplasma gondii infection. To investigate the relationship between CCR5 and abortion in toxoplasmosis, we inoculated wild-type and CCR5-deficient (CCR5^-/-) mice with T. gondii tachyzoites intraperitoneally on day 3 of pregnancy (embryonic day 3 [E3]). The pregnancy rate decreased as pregnancy progressed in infected wild-type mice. Histopathologically, no inflammatory lesions were observed in the fetoplacental tissues. Although wild-type mice showed a higher parasite burden at the implantation sites than did CCR5^-/- mice at E6 (3 days postinfection [dpi]), T. gondii antigen was detected only in the uterine tissue and not in the fetoplacental tissues. At E8 (5 dpi), the embryos in infected wild-type mice showed poor development compared with those of infected CCR5^-/- mice, and apoptosis was observed in poorly developed embryos. Compared to uninfected mice, infected wild-type mice showed increased CCR5 expression at the implantation site at E6 and E8. Furthermore, analyses of mRNA expression in the uterus of nonpregnant and pregnant mice suggested that a lack of the CCR5 gene and the downregulation of tumor necrosis factor alpha (TNF-α) and CCL3 expression at E6 (3 dpi) are important factors for the maintenance of pregnancy following T. gondii infection. These results suggested that CCR5 signaling is involved in embryo loss in T. gondii infection during early pregnancy and that apoptosis is associated with embryo loss rather than direct damage to the fetoplacental tissues.

Review of toxoplasmosis in Morocco: seroprevalence and risk factors for toxoplasma infection among pregnant women and HIV- infected patients

Toxoplasmosis is a disease caused by a protozoal parasite: Toxoplasma gondii. This infection can cause severe illness when the organism is contracted congenitally or when it is reactivated in immunosuppressed people. In this paper we review for the first time prevalence and risk factors of T. gondii among pregnant women and HIV-infected adults in Morocco. A systematic review methodology was used to consult three databases: Pub Med, Science Direct and Google Scholar dated until 2015, regarding prevalence data and risk factors of infection among pregnant women and people living with HIV. Data collection and eligibility criteria were established in this paper. No statistical method was employed in this study. Our review resulted in a total of 6 publications meeting the inclusion criteria of prevalence and risk factors of toxoplasmosis in Morocco. Seropositive rates of T. gondii infection reach up to 51% in pregnant women. Risk factors that were reported included contact with soil, lack of knowledge about toxoplasmosis, and a low educational level. For HIV-infected adults, the limited data show a 62.1% prevalence rate of T. gondii .According to our review, there is still very little information on toxoplasmosis disease in pregnant women and HIV infected patients in Morocco. Further research on toxoplasmosis is needed to better ascertain the human disease burden in Morocco.

Environmental impacts of food consumption by dogs and cats

In the US, there are more than 163 million dogs and cats that consume, as a significant portion of their diet, animal products and therefore potentially constitute a considerable dietary footprint. Here, the energy and animal-derived product consumption of these pets in the US is evaluated for the first time, as are the environmental impacts from the animal products fed to them, including feces production. In the US, dogs and cats consume about 19% ± 2% of the amount of dietary energy that humans do (203 ± 15 PJ yr-1 vs. 1051 ± 9 PJ yr-1) and 33% ± 9% of the animal-derived energy (67 ± 17 PJ yr-1 vs. 206 ± 2 PJ yr-1). They produce about 30% ± 13%, by mass, as much feces as Americans (5.1 ± Tg yr-1 vs. 17.2 Tg yr-1), and through their diet, constitute about 25-30% of the environmental impacts from animal production in terms of the use of land, water, fossil fuel, phosphate, and biocides. Dog and cat animal product consumption is responsible for release of up to 64 ± 16 million tons CO2-equivalent methane and nitrous oxide, two powerful greenhouse gasses (GHGs). Americans are the largest pet owners in the world, but the tradition of pet ownership in the US has considerable costs. As pet ownership increases in some developing countries, especially China, and trends continue in pet food toward higher content and quality of meat, globally, pet ownership will compound the environmental impacts of human dietary choices. Reducing the rate of dog and cat ownership, perhaps in favor of other pets that offer similar health and emotional benefits would considerably reduce these impacts. Simultaneous industry-wide efforts to reduce overfeeding, reduce waste, and find alternative sources of protein will also reduce these impacts.

Toxoplasma gondii, a Foodborne Pathogen in the Swine Production Chain from a European Perspective

Toxoplasmosis is a foodborne zoonosis transmitted by Toxoplasma gondii, a cosmopolitan protozoan that infects humans through exposure to different parasite stages, in particular by ingestion of tissue cysts or tachyzoites contained in meat, primary offal (viscera), and meat-derived products or ingestion of environmental sporulated oocysts in contaminated food or water. The pig is an important species for infection: raw or undercooked pork consumption not subject to treatment able to inactivate the parasite represents a risk to consumers' health. Broadening knowledge of transmission ways and prevalence concerning this important pathogen in swine, together with a thorough acquaintance with hazard management are key elements to avoid T. gondii spreading within the swine production chain. This review aims to illustrate why toxoplasmosis should be regarded as a veterinary public health issue through a careful description of the parasite, routes of infection, and inactivation treatments, highlighting the main prevention lines from pig breeding to pork consumption.

The standardization of 5 immunoassays for anti-Toxoplasma immunoglobulin G(IgG)

BACKGROUND

Quantitative immunoassays to detect IgG antibodies are the most commonly used tests for diagnosing toxoplasmosis. We investigated the current state of standardization of quantitative immunoassays used to measure anti-Toxoplasma IgG levels.

METHODS

Four fully automated immunoassays (Architect i4000ISR, Immulite 2000 Xpi, Siemens; Liaison, DiaSorin; Cobas e601, Roche) and one manual immunoassay (ELISA classic Toxo IgG, Virion Serion) were performed on the following: individual patient serum samples, the WHO international standards, control samples, and calibrators provided by 5 immunoassay manufacturers. Statistical analysis was used to illustrate the results.

RESULTS

No perfect correlation (slope=1.0) was found between any 2 assays. Large differences in anti-Toxoplasma IgG titers were observed among the 5 immunoassays using serum samples from individual patients. Using IS 01/600 as a calibrator minimized the inter-assay variability of anti-Toxoplasma IgG values CONCLUSIONS: There is still significant effort needed towards standardization of anti-Toxoplasma IgG quantitative immunoassays.

East-West Divide: temperature and land cover drive spatial variation of Toxoplasma gondii infection in Eurasian otters (Lutra lutra) from England and Wales

Toxoplasma gondii, a zoonotic parasite of global importance, infects all endothermic vertebrates, with extensive health implications. The prevalence of this parasite is seldom monitored in wildlife. Here, a semi-aquatic species, the Eurasian otter (Lutra lutra) was used as a model to assess the potential effect of climate, land cover and biotic factors on T. gondii seroprevalence in British wildlife. The Sabin–Feldman cytoplasm-modifying dye test identified T. gondii antibodies in 25·5% of blood samples from otters found dead, mainly as road kill, in England and Wales, between 2004 and 2010. Otters in the east of England were more likely to be infected with T. gondii than those in western regions. Land cover and temperature are key determinants of T. gondii infection risk, with more infection in arable areas and lower infection where temperatures are higher. The probability of T. gondii infection increased with host age, reflecting cumulative exposure with time, but there was no association between T. gondii seroprevalence and cause of host death.

Mast cell activator compound 48/40 is not an effective adjuvant for UV-attenuated Toxoplasma gondii vaccine

Toxoplasma gondii (T. gondii, Tg) is a globally distributed parasitic protozoan causing different forms of toxoplasmosis in humans. Mast cells (MCs) play a role during T. gondii infection. Several studies suggest that MC activator compound 48/80 (C48/80) may be an effective vaccine adjuvant resulting in a potent and protective antigen-specific immune response against bacteria or virus infections. The present study was performed to determine whether C48/80 had adjuvant activity for ultraviolet (UV)-attenuated T. gondii vaccine to induce protective immune responses against T. gondii in mouse model. Kunming mice were divided into the following groups: naive mice, naive mice administrated with C48/80 intraperitoneal (i.p.) injection, mice infected by i.p. injection of 10⁴ T. gondii RH strain alone (Tg group), mice infected with 10⁴ RH tachyzoites plus C48/80 administration (Tg + C48/80), mice immunized with UV-Tg alone, and mice immunized with UV-Tg plus C48/80 administration (UV-Tg + C48/80). All the vaccinated mice were challenged with 10⁴ tachyzoites of T. gondii RH strain at the same time as the primary infection. The survival rates, liver histopathologies, liver parasite burdens, and mRNA expression levels of Th1 and Th2 cytokines in the livers and spleens detected by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) were compared among the aforementioned groups after primary infection or challenge infection. The results showed that, compared to the Tg group or Tg + C48/80 group, the UV-Tg + Tg group and UV-Tg + C48/80 + Tg group had significantly prolonged survival time, lower liver histopathological scores, decreased liver parasite burdens, and increased levels of Th1 and Th2 cytokines in the livers and spleens. There was no significant difference of survival time between the UV-Tg + Tg group and the UV-Tg + C48/80 + Tg group; however, the UV-Tg + C48/80 + Tg group showed higher parasite burden, more severe liver histopathology, and decreased IL-4 level compared to the UV-Tg + Tg group. These results indicate that C48/80 had no adjuvant activity for the immunization induced by UV-attenuated T. gondii vaccine.

Purification Toxoplasma gondii Tissue Cysts Using Percoll Gradients

The protozoan parasite Toxoplasma gondii is capable of infecting all warm-blooded animals and humans. Infectious, transmissible forms of the parasite include oocysts produced by the sexual cycle within the definitive feline host and tissue cysts that form Toxoplasma in the central nervous system and muscle during the asexual cycle within all chronically infected warm-blooded hosts. These tissue cysts are populated with slow-growing bradyzoites, which until recently have been thought to be dormant entities in the context of immune sufficiency. Reactivation to active growth during immune suppression is of critical clinical importance. However, little is known about tissue cysts or the bradyzoites they house, as the diversity of tissue cysts cannot be replicated in cell culture systems. This protocol for optimization of tissue cyst purification from the brains of infected mice using Percoll gradients provides an efficient means to recover in vivo-derived tissue cysts that can be applied to imaging, cell biological, biochemical, transcriptomic, and proteomic analyses. © 2017 by John Wiley & Sons, Inc.

Ultrasound-guided core needle biopsy of cervical lymph nodes in the diagnosis of toxoplasmosis

BACKGROUND

Our study investigates whether the histopathological features of toxoplasmic lymphadenitis (TL), specifically noncaseating microgranuloma and follicular hyperplasia, can be obtained by sonographic-guided core needle biopsy (CNB) of cervical lymph nodes.

METHODS

Thirty-two patients seen from June 2014 to March 2015 were positive for toxoplasma immunoglobulin M antibody. Among those patients, 21 underwent CNB of a cervical lymph node and were enrolled in this study. The pathologic findings were reviewed.

RESULTS

Twenty-nine lymph nodes in 21 patients were sampled. Eighteen of the 21 (86%) patients had a microgranuloma without caseating necrosis or giant cells, and all 21 (100%) patients had follicular hyperplasia.

CONCLUSIONS

The histologic findings of TL were detected by sonographic-guided CNB, which can be used as part of the first line of investigation in patients with unexplained cervical adenopathy. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 45:192-196, 2017.

Influenza M1 Virus-Like Particles Consisting of Toxoplasma gondii Rhoptry Protein 4

Toxoplasma gondii infections occur throughout the world, and efforts are needed to develop various vaccine candidates expressing recombinant protein antigens. In this study, influenza matrix protein (M1) virus-like particles (VLPs) consisting of T. gondii rhoptry antigen 4 (ROP4 protein) were generated using baculovirus (rBV) expression system. Recombinant ROP4 protein with influenza M1 were cloned and expressed in rBV. SF9 insect cells were coinfected with recombinant rBVs expressing T. gondii ROP4 and influenza M1. As the results, influenza M1 VLPs showed spherical shapes, and T. gondii ROP4 protein exhibited as spikes on VLP surface under transmission electron microscopy (TEM). The M1 VLPs resemble virions in morphology and size. We found that M1 VLPs reacted with antibody from T. gondii-infected mice by western blot and ELISA. This study demonstrated that T. gondii ROP4 protein can be expressed on the surface of influenza M1 VLPs and the M1 VLPs containing T. gondii ROP4 reacted with T. gondii-infected sera, indicating the possibility that M1 VLPs could be used as a coating antigen for diagnostic and/or vaccine candidate against T. gondii infection.

Toxoplasmosis seroprevalence in Iranian women and risk factors of the disease: a systematic review and meta-analysis

BACKGROUND

Toxoplasmosis is caused by an intracellular obligatory parasite, Toxoplasma gondii, and it has global distribution. The purposes of this systematic review and meta-analysis were to evaluate the seroprevalence of toxoplasmosis in Iranian pregnant women, and girls and women of childbearing age, and identify potentially preventable risk factors.

METHODS

Between November 2014 and February 2017, nine electronic databases that reported data on the T. gondii seroprevalence in Iranian women were searched. Our search resulted in 83 reports published from 1994 to 2017.

RESULTS

The results showed that the pooled estimation for the prevalence of T. gondii using a random-effect model was 43% (95% confidence interval (CI) = 38-48%) in pregnant women and 33% (95% CI = 23-43%) in girls and the childbearing age groups. There was a significant association between the T. gondii seroprevalence with age and the gestational age of conception in pregnant women and those who had contact with cats in both groups.

CONCLUSIONS

This is the first comprehensive systematic review of T. gondii infection seroprevalence in Iranian women, which showed a high prevalence of Toxoplasma infection. Around 57% of pregnant women and 67% of girls and the childbearing age groups were seronegative and thus were susceptible to infection and should be monitored.

Toxoplasma gondii AP2IX-4 Regulates Gene Expression during Bradyzoite Development

Toxoplasma gondii is a single-celled parasite that persists in its host as a transmissible tissue cyst. How the parasite converts from its replicative form to the bradyzoites housed in tissue cysts is not well understood, but the process clearly involves changes in gene expression. Here we report that parasites lacking a cell cycle-regulated transcription factor called AP2IX-4 display reduced frequencies of tissue cyst formation in culture and in a mouse model of infection. Parasites missing AP2IX-4 lose the ability to regulate bradyzoite genes during tissue cyst development. Expressed in developing bradyzoites still undergoing division, AP2IX-4 may serve as a useful marker in the study of transitional forms of the parasite.

Toxoplasma gondii is a protozoan parasite of great importance to human and animal health. In the host, this obligate intracellular parasite persists as a tissue cyst that is imperceptible to the immune response and unaffected by current therapies. The tissue cysts facilitate transmission through predation and give rise to chronic cycles of toxoplasmosis in immunocompromised patients. Transcriptional changes accompany conversion of the rapidly replicating tachyzoites into the encysted bradyzoites, and yet the mechanisms underlying these alterations in gene expression are not well defined. Here we show that AP2IX-4 is a nuclear protein exclusively expressed in tachyzoites and bradyzoites undergoing division. Knockout of AP2IX-4 had no discernible effect on tachyzoite replication but resulted in a reduced frequency of tissue cyst formation following alkaline stress induction—a defect that is reversible by complementation. AP2IX-4 has a complex role in regulating bradyzoite gene expression, as the levels of many bradyzoite mRNAs dramatically increased beyond those seen under conditions of normal stress induction in AP2IX-4 knockout parasites exposed to alkaline media. The loss of AP2IX-4 also resulted in a modest virulence defect and reduced cyst burden in chronically infected mice, which was reversed by complementation. These findings illustrate that the transcriptional mechanisms responsible for tissue cyst development operate across the intermediate life cycle from the dividing tachyzoite to the dormant bradyzoite.

IMPORTANCEToxoplasma gondii is a single-celled parasite that persists in its host as a transmissible tissue cyst. How the parasite converts from its replicative form to the bradyzoites housed in tissue cysts is not well understood, but the process clearly involves changes in gene expression. Here we report that parasites lacking a cell cycle-regulated transcription factor called AP2IX-4 display reduced frequencies of tissue cyst formation in culture and in a mouse model of infection. Parasites missing AP2IX-4 lose the ability to regulate bradyzoite genes during tissue cyst development. Expressed in developing bradyzoites still undergoing division, AP2IX-4 may serve as a useful marker in the study of transitional forms of the parasite.

Protective immunity against toxoplasmosis in mice induced by single-dose immunization with rSAG1/2 protein released from poly(lactide-co-glycolide) microparticles

Triphasic sustained release of tachyzoite chimeric protein, rSAG1/2, from poly(lactide-co-glycolide) (PLG)-encapsulated rSAG1/2 (PLG-rSAG1/2) microparticles (MPs) is a promising characteristic for developing a single-dose vaccine against Toxoplasma gondii in domestic animals. In the present study, we aimed to evaluate whether single immunization with PLG-rSAG1/2 MPs in BALB/c mice would achieve effective immunity and protection against T. gondii. Peritoneal immunization of mice with a single dose of PLG-rSAG1/2 MPs enhanced serum IgG titers and lymphocyte proliferation in a triphasic model over a long 12-week period. In addition, 12 weeks after immunization, significant production of IFN-γ was also monitored in mice vaccinated with one dose of PLG-rSAG1/2 MPs. More importantly, the immunity induced by one dose of PLG-rSAG1/2 MPs protected 70% of mice (14/20) against a lethal subcutaneous challenge of 1 × 10⁴ live tachyzoites of T. gondii (RH strain). In conclusion, a single dose of PLG-rSAG1/2 MPs capable of sustaining triphasic release of rSAG1/2 protein induces long-lasting triphasic immunity against T. gondii in mice. Our data indicate the feasibility of PLG-rSAG1/2 MPs to be developed as a single-dose vaccine against T. gondii for potential use in domestic animals.

A Systematic Review of In vitro and In vivo Activities of Anti-Toxoplasma Drugs and Compounds (2006-2016)

The currently available anti-Toxoplasma agents have serious limitations. This systematic review was performed to evaluate drugs and new compounds used for the treatment of toxoplasmosis. Data was systematically collected from published papers on the efficacy of drugs/compounds used against Toxoplasma gondii (T. gondii) globally during 2006-2016. The searched databases were PubMed, Google Scholar, Science Direct, ISI Web of Science, EBSCO, and Scopus. One hundred and eighteen papers were eligible for inclusion in this systematic review, which were both in vitro and in vivo studies. Within this review, 80 clinically available drugs and a large number of new compounds with more than 39 mechanisms of action were evaluated. Interestingly, many of the drugs/compounds evaluated against T. gondii act on the apicoplast. Therefore, the apicoplast represents as a potential drug target for new chemotherapy. Based on the current findings, 49 drugs/compounds demonstrated in vitro half-maximal inhibitory concentration (IC50) values of below 1 μM, but most of them were not evaluated further for in vivo effectiveness. However, the derivatives of the ciprofloxacin, endochin-like quinolones and 1-[4-(4-nitrophenoxy) phenyl] propane-1-one (NPPP) were significantly active against T. gondii tachyzoites both in vitro and in vivo. Thus, these compounds are promising candidates for future studies. Also, compound 32 (T. gondii calcium-dependent protein kinase 1 inhibitor), endochin-like quinolones, miltefosine, rolipram abolish, and guanabenz can be repurposed into an effective anti-parasitic with a unique ability to reduce brain tissue cysts (88.7, 88, 78, 74, and 69%, respectively). Additionally, no promising drugs are available for congenital toxoplasmosis. In conclusion, as current chemotherapy against toxoplasmosis is still not satisfactory, development of well-tolerated and safe specific immunoprophylaxis in relaxing the need of dependence on chemotherapeutics is a highly valuable goal for global disease control. However, with the increasing number of high-risk individuals, and absence of a proper vaccine, continued efforts are necessary for the development of novel treatment options against T. gondii. Some of the novel compounds reviewed here may represent good starting points for the discovery of effective new drugs. In further, bioinformatic and in silico studies are needed in order to identify new potential toxoplasmicidal drugs.

Detection of Intestinal Pathogens in River, Shore, and Drinking Water in Lima, Peru

Water quality management is an ongoing struggle for many locations worldwide. Current testing of water supplies can be time-consuming, expensive, and lack sensitivity. This study describes an alternative, easy-to-use, and inexpensive method to water sampling and testing at remote locations. This method was employed to detect a number of intestinal pathogens in various locations of Lima, Peru. A total of 34 PCR primer pairs were tested for specificity and high-yield amplification for 12 different pathogens using known DNA templates. Select primers for each pathogen were then tested for minimum detection limits of DNA. Water samples were collected from 22 locations. PCR was used to detect the presence of a pathogen, virulence factors, or differentiate between pathogenic species. In 22 water samples, cholera toxin gene was detected in 4.5% of samples, C. perfringens DNA was detected in 50% of samples, E. histolytica DNA was detected in 54.5% of samples, Giardia intestinalis DNA was detected in 4.5% of samples, Leptospira spp. DNA was detected in 29% of samples, and T. gondii DNA was detected in 31.8% of samples. DNA from three pathogens, C. perfringens, E. histolytica, and T. gondii, were found in residential samples, which accounted for 10 out of 22 samples.

Reexamining Chronic Toxoplasma gondii Infection: Surprising Activity for a "Dormant" Parasite

PURPOSE OF REVIEW

Despite over a third of the world's population being chronically infected with Toxoplasma gondii, little is known about this largely asymptomatic phase of infection. This stage is mediated in vivo by bradyzoites within tissue cysts. The absence of overt symptoms has been attributed to the dormancy of bradyzoites. In this review, we reexamine the conventional view of chronic toxoplasmosis in light of emerging evidence challenging both the nature of dormancy and the consequences of infection in the CNS.

RECENT FINDINGS

New and emerging data reveal a previously unrecognized level of physiological and replicative capacity of bradyzoites within tissue cysts. These findings have emerged in the context of a reexamination of the chronic infection in the brain that correlates with changes in neuronal architecture, neurochemistry, and behavior that suggest that the chronic infection is not without consequence.

SUMMARY

The emerging data driven by the development of new approaches to study the progression of chronic toxoplasma infection reveals significant physiological and replicative capacity for what has been viewed as a dormant state. The emergence of bradyzoite and tissue cyst biology from what was viewed as a physiological "black box" offers exciting new areas for investigation with direct implications on the approaches to drug development targeting this drug-refractory state. In addition, new insights from studies on the neurobiology on chronic infection reveal a complex and dynamic interplay between the parasite, brain microenvironment, and the immune response that results in the detente that promotes the life-long persistence of the parasite in the host.

Influence of Toxoplasma Gondii Infection on Symptoms and Signs of Premenstrual Syndrome: A Cross-sectional Study

Infection with Toxoplasma gondii in brain may cause some symptoms that resemble those in women with premenstrual syndrome. To determine the association of T. gondii infection with symptoms and signs of premenstrual syndrome, we examined 489 women aged 30-40 years old. Sera of participants were analyzed for the presence of anti-Toxoplasma IgG and IgM antibodies using enzyme-linked immunoassays (EIA) and T. gondii DNA by polymerase chain reaction (PCR). Anti-T. gondii IgG antibodies were found in 38 (7.8%) of the women studied. Anti-T. gondii IgM antibodies were found in 13 (34.2%) of the 38 IgG seropositive women. Logistic regression showed two variables associated with seropositivity to T. gondii: presence of diarrhea (odds ratio [OR] = 6.10; 95% confidence interval [CI]: 1.37-27.85; P = 0.01) and weight gain (OR = 2.89; 95% CI: 1.37-6.07; P = 0.005), and two variables associated with high (>150 IU/ml) levels of IgG against T. gondii: presence of diarrhea (OR = 7.40; 95% CI: 1.79-30.46; P = 0.006) and abdominal inflammation (OR = 3.38; 95% CI: 1.13-10.10; P = 0.02). Positivity to EIA IgG and PCR was positively associated with obesity and negatively associated with joint pain by bivariate analysis. Our study for the first time reveals a potential association of T. gondii infection with clinical manifestations of premenstrual syndrome.

The efficacy of herbal medicines against Toxoplasma gondii during the last 3 decades: a systematic review

The objective of the current study was to systematically review papers discussing the efficacy of medicinal herbs against Toxoplasma gondii. Data were systematically collected from published papers about the efficacy of herbs used against T. gondii globally from 1988 to 2015, from PubMed, Google Scholar, ISI Web of Science, EBSCO, Science Direct, and Scopus. Forty-nine papers were included in the current systematic review reporting the evaluation of medicinal plants against T. gondii globally, both in vitro and in vivo. Sixty-one plants were evaluated. Most of the studies were carried out on Artemisia annua. The second highest number of studies were carried out on Glycyrrhiza glabra extracts. RH and ME49 were the predominant parasite strains used. Additionally, Swiss-Webster and BALB/c mice were the major animal models used. Alcoholic and aqueous extracts were used more than other types of extracts. Natural compounds mentioned here may be developed as novel and more effective therapeutic agents that improve the treatment of toxoplasmosis due to their lower side effects, higher availability, and better cultural acceptance compared with those of the chemical drugs that are currently being used.

Seroprevalence of Toxoplasma gondii infection among childbearing age women in Kerman city, southeastern Iran

This cross-sectional study aims to determine the prevalence of IgM and IgG anti-T. gondii antibodies and the associated risk factors among childbearing age women referring to counseling centers before marriage in Kerman city, southeast of Iran. Totally, 300 serum samples were collected from women referred to Central Laboratory for Marriage Consultation in Kerman city were screened for IgG and IgM anti-T. gondii antibodies by enzyme linked immunosorbent assay (ELISA). Out of the 300 serum samples, 38 (12.6 %) tested seropositive for anti-T. gondii antibodies; 31 (10.3 %) samples tested seropositive for only IgG antibody, 1 (0.33 %) tested seropositive for both IgM and IgG and 6 (2.0 %) were positive for IgM antibody alone. Statistical analyses also indicated that seroprevalence of anti-T. gondii antibodies increased with age (p < 0.05). Moreover, some risk factors such as, living in rural regions, contact with cats, raw/half-cooked meat consumption, and agricultural activities were significantly (p < 0.05) related to T. gondii seropositivity. The findings revealed that more than three-quarters of the childbearing age women studied in the present investigation are susceptible to infection during pregnancy. Thus, by adopting correct and improved practices we can improve their living conditions, and prevent infection and awareness and control of pathogens associated with disease is recommended.

Seroprevalence and Risk Factors of Toxoplasma gondii Infection in Farmed Raccoon Dogs (Nyctereutes procyonoides) in China

Toxoplasma gondii, an obligate intracellular apicomplexan parasite, can infect homoiothermal vertebrate animals, including raccoon dogs (Nyctereutes procyonoides). Regretfully, data on T. gondii infection in raccoon dogs were limited in China. Therefore, to investigate the seroprevalence and to evaluate risk factors for T. gondii infection in raccoon dogs, a total of 1181 raccoon dog blood samples were collected from Jilin and Shandong provinces, China, from September to December 2014. The antibodies of T. gondii were examined using the modified agglutination test. Overall, the seroprevalence of T. gondii infection was 8.64% in the examined raccoon dogs. The prevalences of T. gondii infection were different among cities (ranging from 2.96% in Yantai to 17.62% in Qingdao), genders (female: 7.58%; male: 9.22%), and ages (young: 8.53%; subadult: 7.71%; adult: 7.73%). Region was considered as an important risk factor for T. gondii infection in this study. This is the first report of T. gondii infection in raccoon dogs in China, providing baseline information for prevention and control of T. gondii infection in raccoon dogs in Jilin and Shandong provinces, China.

Disseminated toxoplasmosis Toxoplasma gondii in a wild Florida manatee Trichechus manatus latirostris and seroprevalence in two wild populations

Marine mammals are important indicators for ecosystem health and serve as sentinel species for infectious agents including zoonoses. Histological examination of tissues from a stranded Florida manatee Trichechus manatus latirostris revealed protozoal cysts in the cerebrum and intrahistiocytic tachyzoites in the liver and caudal mesenteric lymph node. Disseminated Toxoplasma gondii infection was confirmed by immunohistochemistry and sequencing of the nuclear ribosomal internal transcribed spacer region of formalin-fixed tissues. The lack of baseline information on Florida manatees' exposure to this pathogen prompted a study into the seroprevalence of T. gondii in 2 separate geographic habitats in Florida, USA, during the winters from 2011-2014. Serum was collected during routine health assessments of 44 apparently healthy manatees from Crystal River (n = 26) on the west central coast of Florida and Brevard County (n = 18) on the east coast of Florida. Serum was screened for detection of T. gondii immunoglobulin G (IgG) antibodies via the modified agglutination test. Two animals from Crystal River from 2011 and 2012 (7.7%) and one animal from Brevard County from 2011 (5.6%) tested positive for T. gondii antibodies. Overall seroprevalence for T. gondii was low in the 2 sampled populations and may reflect a low seroprevalence or animal susceptibility. However, continued monitoring of this pathogen in aquatic ecosystems is warranted due to both possible anthropogenic sources and zoonotic potential.

Evaluation of immune responses induced by rhoptry protein 5 and rhoptry protein 7 DNA vaccines against Toxoplasma gondii

Infection with the protozoan parasite Toxoplasma gondii is widespread, and the organism can cause congenital infections in humans. The horizontal transmission of Toxoplasma is even more common than congenital. An effective vaccine strategy brings the prospect of improving Toxoplasma disease control. Rhoptry protein 5 (ROP5) and ROP7 are potential stimulators of humoral and cellular immune responses. In this study, we constructed a multi-antigenic DNA vaccine expressing ROP5 and ROP7 of T. gondii and compared the protective efficacy to single-gene vaccines and control groups. BALB/c mice were immunized intramuscularly three times. The levels of IgG antibodies and cytokines in mice immunized with the multi-antigenic DNA vaccine (pROP5/ROP7) were significantly higher than those in the control mice. Mice vaccinated with pROP5/ROP7 showed a longer survival time (16 days) than single-gene-immunized mice (11 and 12 days, respectively) or control mice (8 days) after a challenge with 1 × 10(4) tachyzoites of RH strain of T. gondii. Furthermore, after intragastric infection with 20 cysts of PRU strain of T. gondii, the number of brain cysts in mice immunized with pROP5/ROP7 was only 25% of the number in control mice. Our results showed that a DNA vaccine encoding ROP5 and ROP7 significantly enhanced protection against T. gondii challenge.

Recombinant canine adenovirus type-2 expressing TgROP16 provides partial protection against acute Toxoplasma gondii infection in mice

We previously demonstrated that the survival time of BALB/c mice challenged with Toxoplasma gondii RH strain was prolonged by immunising the mice with a eukaryotic vector expressing the protein ROP16 of T. gondii. Building upon previous findings, we are exploring improved vaccination strategies to enhance protection. In this work, a novel recombinant canine adenovirus type 2 expressing ROP16 (CAV-2-ROP16) of T. gondii was constructed and identified to express ROP16 in Madin-Darby canine kidney cells (MDCK) cells by western blot (WB) and indirect immunofluorescence (IFA) assays. Intramuscular immunisation of BALB/c mice with CAV-2-ROP16 was performed to evaluate the humoral and cellular immune responses. This vaccination triggered significant humoral and cellular responses, including ROP16-stimulated lymphoproliferation (P<0.05). Compared to control groups, the CAV-2-ROP16 immunised mice had high production of IFN-γ, IL-2 and IL-12 (P<0.05), with a predominance of IgG2a production, but not IL-10 (P>0.05), revealing that a predominant Th1-type response had developed. The cell-mediated cytotoxic activity with high levels of IFN-γ and TNF-α was significantly increased in both CD4⁺ and CD8⁺ T-cell compartments in the mice immunised with CAV-2-ROP16 (P<0.05), compared to three control groups. In addition, when immunised mice were challenged with the RH strain of T. gondii, they showed a significantly increased survival rate (25%) 80days post infection compared with control mice that all died within seven days (P<0.05). The 25% protection rate elicited by the recombinant virus CAV-2-ROP16 has not been achieved in the field of anti-T. gondii vaccination until now. Our work presents the successful use of recombinant virus CAV-2-ROP16 in vaccination protocols to protect against intraperitoneal challenge with the virulent RH strain of T. gondii. This system was shown to be extremely efficient in eliciting humoral and cellular immune responses that led to a significant improvement in survival time in mice.

Toxoplasma gondii seroprevalence in the Portuguese population: comparison of three cross-sectional studies spanning three decades

BACKGROUND

Toxoplasma gondii is an obligate intracellular protozoan infecting up to one-third of the world's population, constituting a life threat if transmitted from mother to child during pregnancy. In Portugal, there is a lack of knowledge of the current epidemiological situation, as the unique toxoplasmosis National Serological Survey was performed in 1979/1980.

METHODS

We studied the seroprevalence trends in the Portuguese general population over the past 3 decades, by assessing chronological spread cross-sectional studies, with special focus on women of childbearing age, by age group, region and gender.

RESULTS

The T. gondii overall seroprevalence decreased from 47% in 1979/1980 to 22% (95% CI 20% to 24%) in 2013. Generally, we observed that the prevalence of T. gondii IgG increased significantly with age and it decreased over time, both in the general population and in the childbearing women (18% prevalence in 2013).

CONCLUSIONS

The scenario observed for the latter indicates that more than 80% of childbearing women are susceptible to primary infection yielding a risk of congenital toxoplasmosis and respective sequelae. Since there is no vaccine to prevent human toxoplasmosis, the improvement of primary prevention constitutes a major tool to avoid infection in such susceptible groups.

Identification, production and assessment of two Toxoplasma gondii recombinant proteins for use in a Toxoplasma IgG avidity assay

The IgG avidity assay is an important tool in the management of suspected toxoplasmosis in pregnant women. This study aimed to produce new Toxoplasma gondii recombinant proteins and to assess their usefulness in an IgG avidity assay. Toxoplasma positive and negative serum samples were used, the former were categorized into low (LGA) and high (HGA) IgG avidity samples. Immunoblots were performed on 30 T. gondii cDNA clones to determine the reactivity and IgG avidity to the expressed proteins. Two of the clones were found to have diagnostic potential and were analyzed further; AG12b encoded T. gondii apical complex lysine methyltransferase (AKMT) protein and AG18 encoded T. gondii forkhead-associated (FHA) domain-containing protein. The His-tagged recombinant proteins, rAG12b and rAG18, were expressed and tested with LGA and HGA samples using an IgG avidity western blot and ELISA. With the IgG avidity western blot, rAG12b identified 86.4% of LGA and 90.9% of HGA samples, whereas rAG18 identified 81.8% of both LGA and HGA samples. With the IgG avidity ELISA, rAG12b identified 86.4% of both LGA and HGA samples, whereas rAG18 identified 77.3% of LGA and 86.4% of HGA serum samples. This study showed that the recombinant antigens were able to differentiate low avidity and high avidity serum samples, suggesting that they are potential candidates for use in the Toxoplasma IgG avidity assay.

Toxoplasma gondii Infection Potentiates Cognitive Impairments of Alzheimer's Disease in the BALB/c Mice

This study tests the hypothesis that in chronic Toxoplasma gondii infection communication among immune cells promotes neuroinflammation through cytokine networks and potentiate cognitive impairments in BALB/c mice with Alzheimer's disease (AD). The animal model of Toxoplasma infection was established by the intraperitoneal inoculation of 20-25 tissue cysts from the Tehran strain of T. gondii . We injected amyloid-beta 1-42 peptide (Aβ_1-42, 1 and 2 μl) into the hippocampus of BALB/c mice to establish an animal model of AD. The behavioral experiments such as spatial learning and memory were performed using the Morris water maze test. The mRNA levels of TNF-α, IL-1β, IFN-γ, and inducible nitric oxide synthase (iNOS) were examined by real-time PCR. We found that T. gondii infection caused AD-like symptoms and impaired learning and memory functions of the infected BALB/c mice. We also found that in Toxoplasma infection + Aβ_1-42 (1 μl) group, T. gondii infection could potentiate AD in infected mice receiving subdoses of Aβ_1-42 (1 μl) and caused considerable impairment in learning and memory functions similar to AD group. Comparison of the results demonstrated that mRNA levels of IL-1β, TNF-α, IFN-γ, and iNOS significantly (P < 0.001) increased in T. gondii + Aβ_1-42 (1 μl) in comparison with the other tested groups. The obtained results showed that chronic T. gondii infection communication among immune cells promotes neuroinflammation through cytokine networks and induces pathological progression of AD in the mice brain, whereas the presence of neuroanatomical Toxoplasma tissue cysts in the brain could also affect the behavioral functions in T. gondii -infected mice.

Seroprevalence and Spatial Distribution of Toxoplasmosis in Sheep and Goats in North-Eastern Region of Pakistan

Toxoplasmosis is a protozoan disease that is caused by Toxoplasma gondii in livestock and humans. Due to its medical and veterinary importance, it is essential to study the seroprevalence of T. gondii infection among humans and animals in various parts of the world. The major objective of this study was to determine the seroprevalence and spatial distribution of toxoplasmosis in small ruminants (sheep and goats) of north-eastern region, Pakistan. A total of 1,000 animals comprising of sheep (n=470) and goats (n=530) were examined for T. gondii infection by using ELISA. An epidemiological data was collected in the form of questionnaire. A surface has been generated by using method of interpolation in Arc GIS with the help of IDW (inverse distance weight). The results showed higher seroprevalence of T. gondii in goats (42.8%) as compared to sheep (26.2%). The seroprevalence was higher in females as compared to males in all examined ruminants. Similarly, there is a wide variation in the seroprevalence of T. gondii in different breeds of sheep and goats showing higher seroprevalence in Teddy (52.8%) and Damani breed (34.5%) of goat and sheep's, respectively. The geographical and spatial distribution of T. gondii shows that it is widely distributed in different parts of the north-eastern region of Pakistan. Our results suggest widespread environmental contamination with T. gondii oocysts. It suggests us that small ruminants could be a potentially important source of T. gondii infection if their infected meat is consumed undercooked.

The impact of socioeconomic factors on the efficiency of voluntary toxoplasmosis screening during pregnancy: a population-based study

BACKGROUND

Congenital toxoplasmosis is associated with severe complications. German state health insurance covers rubella, but not toxoplasmosis, immunity screening. We analysed the effect of socioeconomic factors on the efficiency of private toxoplasmosis screening during pregnancy.

METHODS

Toxoplasmosis and rubella screening data (n = 5402 mothers) were collected within the population-based Survey of Neonates in Pomerania (SNiP).

RESULTS

At the first-trimester screening, 34.4 % (88.1 %) of expecting mothers were immune to toxoplasmosis (rubella). Susceptibility for toxoplasmosis (rubella) was observed in 39.6 % (8.9 %) and 25.8 % (2.95 %) were not tested. Data on a 2(nd) screening were available in a subgroup of women with negative immunity showing less than 45 % participation rate. Active toxoplasmosis (no rubella) infection was observed in 0.3 % (n = 17) of pregnant women. A multiple logistic regression model (AIC = 719.67; AUC = 0.725) revealed that the likelihood of participating in a second toxoplasmosis screening increased among women with a good level of education and a steady partnership and decreased with paternal unemployment and the absence of breastfeeding. The highest probability of non-participation in toxoplasmosis screening was found among women with temporal burden and family responsibilities. A cost-benefit analysis showed that covering general screening for toxoplasmosis with health insurance saved costs.

CONCLUSION

Toxoplasmosis carried a substantial risk of infection during pregnancy. Although increased socioeconomic status was positively associated with the participation in toxoplasmosis screening, this was not the case when pregnant women had strong temporal burden and family responsibilities. This data supports the need for toxoplasmosis screening among pregnant women as a general healthcare benefit covered by insurance.

Investigation of false positives associated with loop-mediated isothermal amplification assays for detection of Toxoplasma gondii in archived tissue samples of captive felids

Toxoplasma gondii is a ubiquitous protozoan parasite that infects humans and many different animals, including felids. Many molecular and serologic tests have been developed for detection of T. gondii in a wide range of hosts. Loop-mediated isothermal amplification (LAMP) is a field-friendly technique that lacks the practical drawbacks of other molecular and serologic tests, and LAMP assays have been successfully developed for detection of T. gondii in fresh tissue samples. In the current study, both a previously published and a de-novo designed LAMP assay were compared to a quantitative real-time (q)PCR assay, for the detection of T. gondii in archived formalin-fixed, paraffin-embedded (FFPE) tissue samples from captive wildlife. The LAMP assays produced conflicting results, generating both false positives and false negatives. Furthermore, the LAMP assays were unable to positively identify samples with low levels of parasites as determined by qPCR and histopathology. Therefore, these LAMP assays may not be the most suitable assays for detection of T. gondii in archived FFPE and frozen tissue samples.