Toxoplasma gondii Research Papers - Academia.edu (original) (raw)

Many parasites induce characteristic changes in behavior of their hosts. In humans latent toxoplasmosis is associated with changes in personality profiles. It has been already shown that a decrease in superego strength is correlated with duration of toxoplasmosis in men. Here we studied changes in personality profiles with Cattell's 16 PF questionnaire in Toxoplasma-infected women. The changes were measured as differences in personality factors between Toxoplasma-infected subjects and uninfected controls of the same age. The low-rate changes were studied in 230 women diagnosed with acute toxoplasmosis during past 14 years. The results showed the correlation between duration of toxoplasmosis and level of factors G (high superego strength) and Q3 (high strength of self sentiment). The high-rate changes were estimated by measuring the correlation between level of Toxoplasma-antibody titers (which rapidly decline after the end of acute phase of toxoplasmosis) and personality factors in an experimental set of 55 young mothers with latent toxoplasmosis. Again, certain factors, namely A (affectothymia), F (surgence), G (high superego strength), H (parmia), and L (protension), correlated with the length of the infection. We suggest that the parasite induced the changes in the personality profiles of the women because of our observation of an increasingly different personality profile over time between women with latent infection and controls. The same evidence questions the view that women with a particular personality

- by Petr Kodym
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- Psychology, Biological Psychology, Cognitive Science, Personality

Equine protozoal myeloencephalitis (EPM) is a neurological disease caused by Sarcocystis neurona, an apicomplexan parasite. S. neurona is also associated with EPM-like diseases in marine and small mammals. The mechanisms of transmission and ability to infect a wide host range remain obscure; therefore, characterization of essential proteins may provide evolutionary information allowing the development of novel chemotherapeutics that target non-mammalian biochemical pathways. In the current study, two-dimensional electrophoresis and matrix-assisted laser desorption ionization-time of flight (MALDI-ToF) mass spectrometry were combined to characterize and identify an enolase protein from S. neurona based on peptide homology to the Toxoplasma gondii protein. Enolase is thought to be a vestigial, nonphotosynthetic protein resulting from an evolutionary endosymbiosis event of an apicomplexan ancestor with green algae. Enolase has also been suggested to play a role in parasite stage conversion for T. gondii. Characterization of this protein in S. neurona and comparison to other protozoans indicate a biochemical similarity of S. neurona enolase to other tissue-cyst forming coccidians that cause encephalitis.

- by Jeffrey Lakritz
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- Microbiology, Parasitology, Medical Microbiology, Toxoplasma gondii
- by nathalie courret
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- Microbiology, Parasitology, Zoology, Cytokines

Background: The infection caused by the parasite Toxoplasma gondii (T. gondii) is often asymptomatic or has mild symptoms. The infection can cause serious problems in pregnant women who acquire the infection during gestation and their fetuses are congenitally infected. Methods: We tested 64 amniotic fluid samples for the presence of T. gondii by using fluorescent PCR and DNA fragment analysis. Later we compared four different molecular biological methods for the detection of the presence of T. gondii on same frozen DNA samples. These methods are the conventional PCR, fluorescent PCR with DNA fragment analysis, quantitative real-time PCR with SYBRGreen I and with fluorescence energy transfer hybridization probe detection. We determined the detection limit of these methods. Results: The conventional PCR and quantitative real-time PCR with SYBRGreen I detection have the detection limit of 1000 parasites, followed by fluorescent PCR with the detection limit of 10 -100 parasites. The real-time PCR using fluorescence energy transfer hybridization probes can detect one parasite. This is the most sensitive and the fastest method. We detected 5 T. gondii positive samples with all methods from the studied 64 amniotic fluids. Conclusions: All studied molecular biological methods are suitable for the detection of congenital toxoplasmosis. The quantitative real-time PCR based methods are more sensitive, simple and easy to perform these are opening the avenue to find out the effect of the number of parasites on fetal abnormalities. D

- by B. Nagy
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- Molecular Biology, Toxoplasma, Toxoplasmosis, Toxoplasma gondii
- by Felix A. Ruiz
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- Electron Microscopy, Fluorescence Microscopy, Calcium, Toxoplasma

A serological survey of toxoplasmosis in pigs in Ghana was carried out between October 1997 and April 1998 in the three ecological zones of Ghana: the Coastal Savannah, the Forest Belt and the Guinea Savannah. Antibody against Toxoplasma gondii was measured in pig serum using a microplate-ELISA which had a sensitivity and specificity of 90.2 and 92.3%, respectively when compared with IFAT. A national seroprevalence of 39% was obtained in pigs, with the ecological distribution being 43.9, 30.5 and 42.5% for the Coastal Savannah, the Forest Belt and the Guinea Savannah, respectively. The age of the animal, the breed, the environmental conditions and the management practices appeared to be the major determinants of prevalence of antibodies against T. gondii. The prevalence of anti-T. gondii antibodies was found to increase with age (P B0.05). Pigs from the two Savannah zones had a significantly higher (PB0.05) antibody prevalence than those sampled from the Forest belt. Antibody prevalence (46.8%) in crossbreed pigs was significantly higher (PB 0.05) than that of the exotic Large White breed (38.8%).

- by su abdullah
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- Ghana, Toxoplasma, Toxoplasma gondii, Biological Sciences

Toxoplasma gondii is an obligate intracellular parasite, able to disseminate into deep tissues and cross biological barriers, reaching immunoprivileged sites such as the brain and retina. In order to investigate whether the parasite uses leukocyte trafficking to disseminate throughout the host, the adhesive potential to extracellular matrix components, the expression of adhesion molecules and the in vivo migration of murine macrophages infected with RH strain of T. gondii were investigated. Cellular adhesion to fibronectin, laminin and collagen IV decreased after 24 h of T. gondii infection. However, the decrease in adhesion of infected macrophages observed at early infection was reversed after 48 h. Moreover, decreased adhesion was dependent on active penetration, since heat-killed parasites were unable to reproduce it. Expression of integrins aL, a4 and a5 chains was downmodulated early postinfection, but a progressive regain of expression was observed after 12 h of infection. Expression of b2, av and a4 integrins by peritoneal macrophages at late infection was also gradually reestablished. The assessment of in vivo migration of infected macrophages labeled with the fluorescent dye 5-chloromethylfluorescein diacetate showed a 48-h delay in migration to cervical lymph nodes when compared to LPS pre-stimulated macrophages. Furthermore, cells that migrate to distal lymph nodes were loaded with live parasites. Taken together, these results provide insights about T. gondii escape from the host immune response, placing the macrophage as a "Trojan horse", contributing to parasite dissemination and access to immunoprivileged sites.

- by Flávia Ribeiro-gomes
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- Microbiology, Immunology, Immune response, Medical Microbiology

Toxoplasmosis is a neglected tropical disease with a global distribution that is estimated to infect one third of the world’s human population. This study was a comparison of ELISA and rapid Immunochromatographic tests (ICT) in diagnosis of toxoplasmosis in Port Harcourt Nigeria. Eight hundred patients grouped in four categories from three Health Care Centres were randomly sampled after due ethical approval was obtained. Samples were analysed using Toxo IgG-IgM rapid test (ICT) and Enzyme linked Immunosorbent Assay (ELISA) technique. Socio Demo graphic Data were obtained using well-structured questionnaires. The seroprevalence of toxoplasmosis based on ICT was 28.1% while that of ELISA was 34.5% both significant (P < 0.05) with a relative risk of 0.815. The diagnostic parameters of ICT versus ELISA IgG were sensitively 46.7% specificity 81.7% positive predictive value (PPV) 57.3%, Negative predictive value (NPV) 74.4 with a diagnostic efficiency of 69.6% Cohen Kappas indicate goo...

- by AUSTIN E. Abah
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- Differential Psychology, Toxoplasmosis, Toxoplasma gondii, Diagnosis

The l)eroxidase-antiperoxidase immunolfistocllemical tecimique was employed to stain fi~rmalin fixed, paraffin embedded tissue sections from three cases of enceplmlitis caused by Toxoplasma gondii. We studied two cases of congenital infection and one case of acquired toxoplasmosis occurring in an immunoconapromised host. The peroxidase-antiperoxidase method was exquisitely sensitive and highly specific and stained both the encysted and tachyzoite forms of the organism, as well as allowing for easy identification of infected cells. In two cases of necrotizing encel~halitis--4me congenital, the other acqtfired--widespread dis-

- by J. Remington
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- Toxoplasma, Toxoplasmosis, Toxoplasma gondii, Peroxidase

Between 20% and 60% of the population of most countries are infected with the protozoan Toxoplasma gondii. Subjects with clinically asymptomatic life-long latent toxoplasmosis differ from those who are Toxoplasma free in several behavioural parameters. Case-control studies cannot decide whether these differences already existed before infection or whether they were induced by the presence of Toxoplasma in the brain of infected hosts. Here we searched for such morphological differences between Toxoplasma-infected and Toxoplasma-free subjects that could be induced by the parasite (body weight, body height, body mass index, waist-hip ratio), or could rather correlate with their natural resistance to parasitic infection (fluctuating asymmetry, 2D[ratio ]4D ratio). We found Toxoplasma-infected men to be taller and Toxoplasma-infected men and women to have lower 2D[ratio ]4D ratios previously reported to be associated with higher pre-natal testosterone levels. The 2D[ratio ]4D ratio negat...

- by Jaroslav Flegr
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- Parasitology, Fluctuating asymmetry, Innate immunity, Toxoplasmosis

Mice models of toxoplasmosis using ocular instillation of tachyzoites, were limited to explore ocular pathology using optical microscopy and ultrastructural examination. Here we investigated possible correlations between behavioral changes assessed by hippocampal-dependent tasks and associated hippocampal pathology using tachyzoites from type I RH strain. Tachyzoites were instilled in ocular conjunctive of BALB/c adult female mice model. BALB/c mice were submitted to the hippocampal-dependent elevated plus maze task (EPM), before and after instillation of 10 µl of an infected suspension containing 1.6 x 10 6 parasites/mL. Control animal received equal volume of saline in the left eye. Two-tail, t-tests revealed significant differences between pre-and post-inoculation EPM results, with an increase in the time spent in closed arms and a reduction in the time spent in open arms, a reduction in the distance traveled, and an increase in immobile time in infected subjects. In contrast, no-significant differences were detected between pre-and post-instillation in the EPM outcomes in control mice. Microglia activation and sparse clusters formation of activated microglia and cell death were observed in the subiculum and entorhinal cortex of infected mice. Taken together, neuropathological and behavioral changes suggest that ocular instilled tachyzoites from type I RH strain in BALB/c mouse may be a reliable experimental model to investigate host immune response in toxoplasmosis.

- by Daniel G Diniz and +1
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- Toxoplasma gondii, Mice

As part of conservation efforts between 1997 and 2001, more than 25% (332 animals) of the endangered Hawaiian monk seal (Monachus schauinslandi) population was sampled in the northwestern Hawaiian Islands. Serum samples were tested for antibodies to viruses, bacteria, and parasites known to cause morbidity and mortality in other marine mammal species. Antibodies were found to phocine herpesvirus-1 by using

- by John Reif
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- Zoology, Toxoplasma, Communicable Diseases, Toxoplasma gondii

The association among anthropogenic environmental disturbance, pathogen pollution and the emergence of infectious diseases in wildlife has been postulated, but not always well supported by epidemiologic data. Specific evidence of coastal contamination of the marine ecosystem with the zoonotic protozoan parasite, Toxoplasma gondii, and extensive infection of southern sea otters (Enhydra lutris nereis) along the California coast was documented by this study. To investigate the extent of exposure and factors contributing to the apparent emergence of T. gondii in southern sea otters, we compiled environmental, demographic and serological data from 223 live and dead sea otters examined between 1997 and 2001. The T. gondii seroprevalence was 42% (49/116) for live otters, and 62% (66/107) for dead otters. Demographic and environmental data were examined for associations with T. gondii seropositivity, with the ultimate goal of identifying spatial clusters and demographic and environmental r...

- by C. Kreuder and +3
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- Microbiology, Zoology, Spatial Analysis, Aging

D'Amore, E., Falcone, E., Busani, L. and Tollis, M., 1997. A serological survey of feline immunode¢ciency virus and Toxoplasma gondii in stray cats. Veterinary Research Communications, 21 (5), 355^359

- by Eliane Falcone
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- Toxoplasma, Veterinary, Toxoplasma gondii, Cats
- by Roy Melendez
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- Toxoplasma gondii, Biological Sciences

Different transmission routes, including the ingestion of undercooked meat, can result in Toxoplasma gondii infection in humans. The development of effective prevention strategies is hampered by a lack of quantitative information on the contamination level of different types of meat. Therefore, we developed a method for detection and quantification of T. gondii. The method involved preparation of crude DNA extract from hundred gram samples of meat, magnetic capture of T. gondii DNA and, quantitative real-time PCR targeting the T. gondii 529-bp repeat element. The detection limit of this assay was approximately 230 tachyzoites per 100 g of meat sample. There was a linear relation between the number of parasites added to the samples and Cp-values. Results obtained with the PCR method were comparable to bioassay results for experimentally infected pigs, and to serological findings for sheep. In addition, the T. gondii in 50% of the positive sheep samples could be genotyped by sequencing of the GRA6 gene, after isolation of the gene by magnetic capture. Two subtypes of GRA6 type II were identified in the 16 samples from sheep. For seven samples, the identification of T. gondii as type II was confirmed by microsatellite typing. The PCR method can be used as an alternative to bioassay for detection and genotyping of T. gondii, and to quantify the organism in meat samples of various sources.

- by Hein Sprong
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- Microbiology, Toxoplasma, Industrial Biotechnology, Food Microbiology

The discovery of Toxoplasma gondii independently by Nicolle and Manceaux (1908) and Splendore (1908) was to open a "Pandora's Box" that has led research on this parasite into a number of scientific disciplines. In the 100 years since its discovery, the mystery surrounding T. gondii and its interrelationship with humans has continued to provide a stimulating source of material in many areas of research, resulting in the publication of almost 20,000 papers and a number of books. This flood of diverse information shows no sign of abating, with an average of 10 papers per week appearing in PubMed. Herein, it is impossible to do more than provide a very superficial comment on what has become a massive body of scientific information. T. gondii has many unique features and seems to be the "exception to almost every rule" thus acting as a focus for research in disciplines from epidemiology to immunology to human behaviour to cell biology to human disease. In this review a number of the historical advances will be mentioned and combined with a description of the basic biology of the parasite.

- by David Ferguson
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- History, Medical Microbiology, Toxoplasma, Toxoplasmosis

We compared a new assay for Toxoplasma IgM on the Access™ analyzer (Beckman Coulter, Inc., Chaska, MN, USA), a random access instrument based on the principle of paramagnetic particle enzyme immunoassay with an enzyme-linked immunosorbent assay (ELISA) (Zeus Scientific, Inc., Raritan, NJ, USA) and an immunofluorescent assay (IFA) (Gull Laboratories, Inc., Salt Lake City, UT, USA). Four hundred fresh, unfrozen clinical samples from pregnant women (n ϭ 154), HIV positive patients (n ϭ 41), and patients in whom infection with Toxoplasma gondii was suspected (n ϭ 200) were collected and assayed over a three month period. The specificity of the Access assay was compared to the consensus results. Results that were discrepant between the ELISA and IFA were resolved using a third IFA (Zeus). Once resolved, the specificity for the Access assay, the Zeus ELISA and the Gull IFA were 99.22%, 97.91%, and 99.45%, respectively. We conclude that the Access assay specificity is comparable to consensus results, minimizing false positive results; and because it is a random access instrument, it may be preferable over batch methods.

- by Amin Mohammad
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- Microbiology, Medical Microbiology, Toxoplasma gondii, Clinical Sciences

Toxoplasma gondii undergoes stage conversion between the rapidly dividing tachyzoite that is responsible for acute toxoplasmosis and the slowly replicating, encysted bradyzoite stage. This process of tachyzoite-bradyzoite interconversion is central to the pathogenesis and longevity of infection. Recent research has identified several stage-specific genes and proteins. However, despite recent advances in the understanding of Toxoplasma cell biology, more research is necessary to elucidate the complex events occurring during tachyzoite-bradyzoite interconversion. Here, a brief summary of this process is provided and a new method to characterize gene expression during interconversion is introduced.

- by Russell Lyons
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- Genetics, Toxoplasma, Cell Biology, Gene expression

Loop-mediated isothermal amplification (LAMP) method amplifies DNA with high specificity, sensitivity and rapidity. In this study, we used a conserved sequence in the 200-to 300-fold repetitive 529 bp gene of Toxoplasma gondii to design primers for LAMP test. Detection limit of T. gondii LAMP assay with the primers is 1 pg/lL of T. gondii DNA, which was evaluated using 10-fold serially diluted DNA of cultured parasites. Furthermore, LAMP and conventional PCR methods were applied for amplification of the T. gondii DNA extracted from the lymph nodes taken from pigs which were suspected to be Toxoplasma infection. As a result, 76.9% (70/91) and 85.7% (78/91) of the samples were positive on PCR and LAMP analyzes, respectively. Therefore, the LAMP has a potential to be applied as an alternative molecular diagnostic tool for detection of T. gondii infection from veterinary samples. This is the first study, which applies the LAMP method to diagnose Toxoplasma from veterinary samples.

- by Oriel Thekisoe
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- Microbiology, Toxoplasma, Molecular Diagnostics, Toxoplasma gondii

Detailed postmortem examination of southern sea otters (Enhydra lutris nereis) found along the California (USA) coast has provided an exceptional opportunity to understand factors influencing survival in this threatened marine mammal species. In order to evaluate recent trends in causes of mortality, the demographic and geographic distribution of causes of death in freshly deceased beachcast sea otters necropsied from 1998-2001 were evaluated. Protozoal encephalitis, acanthocephalan-related disease, shark attack, and cardiac disease were identified as common causes of death in sea otters examined. While infection with acanthocephalan parasites was more likely to cause death in juvenile otters, Toxoplasma gondii encephalitis, shark attack, and cardiac disease were more common in prime-aged adult otters. Cardiac disease is a newly recognized cause of mortality in sea otters and T. gondii encephalitis was significantly associated with this condition. Otters with fatal shark bites were over three times more likely to have preexisting T. gondii encephalitis suggesting that shark attack, which is a long-recognized source of mortality in otters, may be coupled with a recently recognized disease in otters. Spatial clusters of cause-specific mortality were detected for T. gondii encephalitis (in Estero Bay), acanthocephalan peritonitis (in southern Monterey Bay), and shark attack (from Santa Cruz to Point Añ o Nuevo). Diseases caused by parasites, bacteria, or fungi and diseases without a specified etiology were the primary cause of death in 63.8% of otters examined. Parasitic disease alone caused death in 38.1% of otters examined. This pattern of mortality, observed predominantly in juvenile and prime-aged adult southern sea otters, has negative implications for the overall health and recovery of this population.

- by Linda Lowenstine
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- Zoology, Mortality, Toxoplasma gondii, Wildlife Diseases
- by Samia A Abdul-Rahman
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- Dementia, Toxoplasma gondii

Toxoplasma gondii merupakan protozoa obligat intraseluler, terdapat dalam tiga bentuk yaitu takizoit (bentuk proliferatif), kista (berisi bradizoit) dan ookista (berisi sporozoit). Toxoplasma gondii adalah parasit yang membutuhkan tubuh inang untuk bereplikasi dan bertahan hidup. Toxoplasma gondii pada awal perkambangannya pertama kali berada dalam tubuh inang definitive seperti kucing dan tikus. Daur hidup Toxoplasma gondii melalui dua siklus enteroepitel dan siklus ekstraintestinal. Siklus enteroepitelial di dalam tubuh hospes definitive seperti kucing. Kemudian ookista yang dikeluarkan bersama kotoran kucing akan berada dilingkungan dan menjadi sporo kista dan jika tertelan manusia akan menginfeksi dengan segera. Toxoplasma gondii merupakan mikroorganisme berbahaya karena dapat menyebabkan beberapa penyakit akut hingga kelainan dan kematian pada janin. Pencegahan dini dan pengobatan untuk toxoplasmosis (infeksi akibat T. gondii) terus dikembangkan hingga saat ini. Pencegahan dini yang harus dilakukan terutama pada ibu hamil adalah menjauhi hospes definif seperti kucing dan tikus dan memasak makanan secara matang sempurna. Pengambangan vaksin terus dikembangkan untuk menghindari infeksi akut oleh parasit Toxoplasma gondii.

- by Eko Purnomo
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- Toxoplasma gondii
- by Alan Sher
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- Immunology, Immunology of the Gut, Toxoplasma gondii, Tuberculosis
- by E. Olivalves and +1
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- Toxoplasma gondii, Systemic Lupus Erythematosus, Diabetes mellitus, Clinical Sciences

Toksoplasmosis adalah penyakit menular zoonotik yang disebabkan Toxoplasma gondii, dilaporkan bersifat endemik di hampir seluruh kepulauan di Indonesia. Angka prevalensi penyakit pada domba berkisar 8-84%, kambing 21-67%, kucing 10-40%, babi 24-38%, sapi 24-41%, kerbau 14-32%, ayam 16-34%, itik 6%, anjing 10-18% dan manusia 14-82%. Penyakit ini dapat menyebabkan gejala abortus, kelahiran prematur, ensefalitis pada janin dan mumifikasi pada kambing dan domba. Penyakit ini dapat menyebabkan keguguran pada wanita hamil. Makalah ini membahas mengenai distribusi, angka prevalensi, siklus hidup, cara penularan, gejala klinis, pencegahan toksoplasmosis melalui pola makan dan hidup sehat dan pengobatannya.

- by Ryo Fadlies
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- Toxoplasma gondii

The rise of the AIDS epidemic made the requirement for T cells in our continuous protection from pathogens critically apparent. The striking frequency with which AIDS patients exhibited profound neurological pathologies brought attention to many chronic infections that are latent within the immune-privileged CNS. One of the most common lethal opportunistic infections of these patients was with the protozoan parasite, Toxoplasma gondii. Reactivation of Toxoplasma cysts within the brain causes massive tissue destruction evidenced as multiple ring-enhancing lesions on MRI and is called toxoplasmic encephalitis (TE). TE is not limited to AIDS patients, but rather is a risk for all severely immunocompromised patients, including recipients of chemotherapy or transplant recipients. The lessons learned from these patient populations are supported by T cell depletion studies in mice. Such experiments have demonstrated that CD4+ and CD8+ T cells are required for protection against TE. Although it is clear that these T cell subsets work synergistically to fight infection, much evidence has been generated that suggests CD8+ T cells play a dominant role in protection during chronic toxoplasmosis. In other models of CNS inflammation, such as intracerebral infection with LCMV and experimental autoimmune encephalomyelitis (EAE), infiltration of T cells into the brain is harmful and even fatal. In the brain of the immunocompetent host, the well-regulated T cell response to T. gondii is therefore an ideal model to understand a controlled inflammatory response to CNS infection. This review will examine our current understanding of CD8+ T cells in the CNS during T. gondii infection in regards to the (1) mechanisms governing entry into the brain, (2) cues that dictate behavior within the brain, and (3) the functional and phenotypic properties exhibited by these cells.

- by Tyler Landrith
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- T Cell biology, Toxoplasma gondii, Brain Inflammation, Chronic Inflammation
- by Sreekumar Chirukandoth
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- Parasitology, Toxoplasma, Toxoplasma gondii, Cats

Résumé La séroprévalence de la toxoplasmose a été étudiée, entre mai et décembre 2007, auprès de 839 femmes enceintes, venues en consultation dans deux hôpitaux de Franceville (Gabon). Le diagnostic sérologique a été fait par la technique ELFA (Enzyme Linked Fluorescent Assay) pour le dosage des IgG, des IgM et les tests d’avidité. Parmi les femmes, 56 % étaient immunisées contre

- by Ulrick Bisvigou
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- Toxoplasma, Adolescent, Toxoplasma gondii, Prospective studies
- by Tatiana Scorza
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- Toxoplasma, Toxoplasma gondii, Biological Sciences, Infection and immunity

TORCH adalah Penyakit infeksi yang disebabkan oleh sekelompok virus HIV, Rubella, Cytomegalovirus (CMV), virus herpes simplex dan parasit Toxoplasma gondii, yang dapat menyerang semua kalangan, dan paling berbahaya jika menyerang anda... more

- by Dalli Mutia
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- Toxoplasma gondii, ELISA, Cytomegalovirus

A debatable link between dementia and toxoplasmosis has recently emerged with a crawling research on humans. This study aims to compare prevalence of toxoplasmosis among elderly persons with different types of dementia and monitor changes in serum Cu and Zn with dementia and/or toxoplasmosis. Seven out of 37 persons with dementia and one of 64 controls were toxoplasmosis positive revealing a highly significant difference. Toxoplasmosis was more common among patients with degenerative dementia (including AD) than those with vascular or mixed dementia were, but the difference was not significant. There was a significant decrease in Zn among dementia cases than control. Using regression analysis, age and marital status could significantly predict both type of dementia and toxoplasmosis and these results support the hypothesis that toxoplasma gondii is strongly associated to dementia.

- by Samia A Abdul-Rahman
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- Dementia, Alzheimer's Disease, Toxoplasmosis, Toxoplasma gondii

Background: Codon optimization and subcellular targeting were studied with the aim to increase the expression levels of the SAG1 78-322 antigen of Toxoplasma gondii in tobacco leaves. The expression of the tobacco-optimized and native versions of the SAG1 gene was explored by transient expression from the Agrobacterium tumefaciens binary expression vector, which allows targeting the recombinant protein to the endoplasmic reticulum (ER) and the apoplast. Finally, mice were subcutaneously and orally immunized with leaf extracts-SAG1 and the strategy of prime boost with rSAG1 expressed in Escherichia coli was used to optimize the oral immunization with leaf extracts-SAG1.

- by Mariana Corigliano and +1
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- Technology, Tobacco, Toxoplasma, Toxoplasma gondii

The obligate intracellular parasite Toxoplasma gondii uses gliding motility to migrate across the biological barriers of the host and to invade cells. This unique form of locomotion requires an intact actin cytoskeleton and involves at least one motor protein (TgMyoA) that belongs to the class XIV of the myosin superfamily. TgMyoA is anchored in the inner membrane complex and is essential for the gliding motion, host cell invasion and egress of T. gondii tachyzoites. TgMyoD is the smallest T. gondii myosin and is structurally very closely related to TgMyoA. We show here that TgMyoD exhibits similar transient kinetic properties as the fast single-headed TgMyoA. To determine if TgMyoD also contributes to parasite gliding motility, the TgMyoD gene was disrupted by double homologous recombination. In contrast to TgMyoA, TgMyoD gene is dispensable for tachyzoite propagation and motility. Parasites lacking TgMyoD glide normally and their virulence is not compromised in mice. The fact that TgMyoD is predominantly expressed in bradyzoites explains the absence of a phenotype observed with myodko in tachyzoites and does not exclude a role of this motor in gliding that would be restricted to the cyst forming but nevertheless motile stage of the parasite.

- by Miklos Nyitrai
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- Physiology, Kinetics, Toxoplasma, Toxoplasma gondii

Microbial pathogens in food cause an estimated 6.5-33 million cases of human illness and up to 9,000 deaths in the United States each year. Over 40 different foodborne microbial pathogens, including fungi, viruses, parasites, and bacteria, are believed to cause human illnesses. For six bacterial pathogens, the costs of human illness are estimated to be 9.3−9.3-9.3−12.9 billion annually. Of these costs, 2.9−2.9-2.9−6.7 billion are attributed to foodborne bacteria. These estimates were developed to provide analytical support for USDA's Hazard Analysis and Critical Control Point (HACCP) systems rule for meat and poultry. (Note that the parasite Toxoplasma gondii is not included in this report.) To estimate medical costs and productivity losses, ERS uses four severity categories for acute illnesses: those who did not visit a physician, visited a physician, were hospitalized, or died prematurely. The lifetime consequences of chronic disease are included in the cost estimates for E. coli O157:H7 and fetal listeriosis.

- by Tanya Roberts and +1
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- Food Safety, Health Economics, Agricultural Economics, Toxoplasma gondii

We reviewed prominent emerging infectious diseases of cetaceans, examined their potential to impact populations, re-assessed zoonotic risk and evaluated the role of environmental stressors. Cetacean morbilliviruses and papillomaviruses as well as Brucella spp. and Toxoplasma gondii are thought to interfere with population abundance by inducing high mortalities, lowering reproductive success or by synergistically increasing the virulence of other diseases. Severe cases of lobomycosis and lobomycosis-like disease (LLD) may contribute to the death of some dolphins. The zoonotic hazard of marine mammal brucellosis and toxoplasmosis may have been underestimated, attributable to frequent misdiagnoses and underreporting, particularly in developing countries and remote areas where carcass handling without protective gear and human consumption of fresh cetacean products are commonplace. Environmental factors seem to play a role in the emergence and pathogenicity of morbillivirus epidemics, lobomycosis/LLD, toxoplasmosis, poxvirus-associated tattoo skin disease and, in harbour porpoises, infectious diseases of multifactorial aetiology. Inshore and estuarine cetaceans incur higher risks than pelagic cetaceans due to habitats often severely altered by anthropogenic factors such as chemical and biological contamination, direct and indirect fisheries interactions, traumatic injuries from vessel collisions and climate change.

- by Ursula Siebert
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- Climate Change, Reproduction, Population ecology, Climate

Human toxoplasmosis in Caldas is a frequent illness. The true importance of the consumption of uncooked meat has not been determined as a possible infection source. In Colombia, the animal production has optimum conditions for the development of the biological cycle of Toxoplasma gondii and the infection in different species of human consumption. In this research the prevalence of antibodies

- by ricardo andres
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- Animal Production, Toxoplasma gondii
- by Helene Barbosa and +1
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- Parasitology, Electron Microscopy, Skeletal muscle biology, Toxoplasma

Toxoplasma gondii occurs through an active process that involves dynamic events, such as gliding motility and conoid extrusion, followed by a sequential secretion from specialized secretory organelles. Increase of intracellular Ca 2+ by ionophores induces conoid extrusion, although in an irreversible way, thus limiting the characterization of the regulatory pathways. In this report we studied the effect of different activating conoid conditions to characterize the regulatory mechanisms involved. Exposure of tachyzoites to ethanol, a well-known activator of microneme secretion through the increase of intracellular Ca 2+ , induced conoid extrusion without affecting parasite viability nor its in vitro invasive capability, in a process that could be completely reverted and repeatedly reactivated. A temporal relationship between conoid extrusion and microneme secretion was here studied. Under this condition, signal transduction pathways and the precise role of the parasite cytoskeleton were characterized. Our results indicate that phospholipase C, Ca 2+ released through channels sensitive to inositol-3-phosphate and ryanodine, as well as myosin together with actin filaments, but not microtubules, all participate in conoid extrusion. Specific inhibitors for serine-threonine kinases blocked conoid extrusion; in contrast, calmodulin inhibitors did not affect the induction. A regulatory model for conoid activation is here proposed.

- by Rosi Mondragon
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- Microbiology, Medical Microbiology, Calcium, Toxoplasma

- by Tino Krell and +2
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- Genetics, Enzyme Inhibitors, Toxoplasma, Multidisciplinary

Exposure of bobcats (Lynx rufus) and gray foxes (Urocyon cinereoargenteus )t o a range of common canine and feline pathogens was assessed in urban and rural zones of Golden Gate National Recreation Area, a National Park in the San Francisco Bay Area, (California, USA) from 1992 to 1995. Testing included serology for canine distemper virus, canine parvovirus (CPV), canine adenovirus,

- by Bruno Chomel
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- Zoology, Disease ecology, Carnivora, Toxoplasma gondii

Thiosemicarbazone and 4-thiazolidinone derivatives were synthesized in one and two step, respectively, from thiosemicarbazide, in satisfactory yields. Then, the synthesized compounds were submitted to evaluation against host cells infected with Toxoplasma gondii. The present studies showed that thiosemicarbazones 2 and 4-thiazolidinone derivatives 3 were effective against intracellular T. gondii.

- by Edesio Melo
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- Organic Chemistry, Toxoplasma, Toxoplasma gondii, Cercopithecus aethiops

All eukaryotes express mitogen-activated protein kinases (MAPKs) that govern diverse cellular processes including proliferation, differentiation and survival. Even though these proteins are highly conserved throughout nature, MAPKs from closely related species often possess distinct signature sequences, making them well-suited as drug discovery targets.

- by Matthew Burow
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- Evolutionary Biology, Genetics, Molecular Evolution, Drug Discovery

However, in many infections the effect on the lymphatics may be both consistent and clinically marked. The lymphadenopathy may be local or generalized and lymphadenopathy is or can be a significant feature of acute HIV infection, primary Herpes simplex, some rickettsial infections, tularaemia, plague, cat-scratch fever due to Bartonella henselae, primary syphilis, lymphogranuloma venereum, chancroid, leptospirosis, brucellosis, relapsing fever, African

- by Wayne Melrose and +1
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- Papua New Guinea, Toxoplasma gondii, Lymphatic Filariasis, Cytomegalovirus

During infections with intracellular microbes, macrophages have two roles. On the one hand, they are important effector cells for the control and killing of intracellular bacteria and protozoan parasites by oxidative and non-oxidative mechanisms. On the other hand, macrophages may also serve as longterm host cells that facilitate the replication and survival of the pathogens, for example, by protecting them against toxic components of the extracellular milieu. In this review, Christian Bogdan and Martin Röllinghoff summarize some of the more recently discovered mechanisms by which intracellular protozoan parasites, such as Leishmania spp, Trypanosoma cruzi and Toxoplasma gondii, manage to exploit macrophages as safe target cells.

- by Christian Bogdan
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- Parasitology, Immunology, Macrophages, Toxoplasma gondii