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Bando H, Murata Y, Han Y, Sugi T, Fukuda Y, Bzik DJ, Fox BA, Kato K. Toxoplasma gondii chitinase-like protein TgCLP1 regulates the parasite cyst burden. Front Cell Infect Microbiol 2024; 14:1359888. [PMID: 38828265 PMCID: PMC11140023 DOI: 10.3389/fcimb.2024.1359888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 04/23/2024] [Indexed: 06/05/2024] Open
Abstract
Toxoplasma, an important intracellular parasite of humans and animals, causes life-threatening toxoplasmosis in immunocompromised individuals. Although Toxoplasma secretory proteins during acute infection (tachyzoite, which divides rapidly and causes inflammation) have been extensively characterized, those involved in chronic infection (bradyzoite, which divides slowly and is surrounded by a cyst wall) remain uncertain. Regulation of the cyst wall is essential to the parasite life cycle, and polysaccharides, such as chitin, in the cyst wall are necessary to sustain latent infection. Toxoplasma secretory proteins during the bradyzoite stage may have important roles in regulating the cyst wall via polysaccharides. Here, we focused on characterizing the hypothetical T. gondii chitinase, chitinase-like protein 1 (TgCLP1). We found that the chitinase-like domain containing TgCLP1 is partially present in the bradyzoite microneme and confirmed, albeit partially, its previous identification in the tachyzoite microneme. Furthermore, although parasites lacking TgCLP1 could convert from tachyzoites to bradyzoites and make an intact cyst wall, they failed to convert from bradyzoites to tachyzoites, indicating that TgCLP1 is necessary for bradyzoite reactivation. Taken together, our findings deepen our understanding of the molecular basis of recrudescence and could contribute to the development of novel strategies for the control of toxoplasmosis.
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Affiliation(s)
- Hironori Bando
- Laboratory of Sustainable Animal Environment, Graduate School of Agricultural Science, Tohoku University, Osaki, Miyagi, Japan
- Department of Parasitology, Asahikawa Medical University, Asahikawa, Hokkaido, Japan
| | - Yuho Murata
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
| | - Yongmei Han
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
| | - Tatsuki Sugi
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
- Division of Collaboration and Education, International Institute for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Yasuhiro Fukuda
- Laboratory of Sustainable Animal Environment, Graduate School of Agricultural Science, Tohoku University, Osaki, Miyagi, Japan
| | - David J. Bzik
- Department of Microbiology and Immunology, The Geisel School of Medicine at Dartmouth, Lebanon, NH, United States
| | - Barbara A. Fox
- Department of Microbiology and Immunology, The Geisel School of Medicine at Dartmouth, Lebanon, NH, United States
| | - Kentaro Kato
- Laboratory of Sustainable Animal Environment, Graduate School of Agricultural Science, Tohoku University, Osaki, Miyagi, Japan
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
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Sokol-Borrelli SL, Reilly SM, Holmes MJ, Orchanian SB, Massmann MD, Sharp KG, Cabo LF, Alrubaye HS, Martorelli Di Genova B, Lodoen MB, Sullivan WJ, Boyle JP. A transcriptional network required for bradyzoite development in Toxoplasma gondii is dispensable for recrudescent disease. Nat Commun 2023; 14:6078. [PMID: 37770433 PMCID: PMC10539341 DOI: 10.1038/s41467-023-40948-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 08/16/2023] [Indexed: 09/30/2023] Open
Abstract
Identification of regulators of Toxoplasma gondii bradyzoite development and cyst formation is the most direct way to address the importance of parasite development in long-term persistence and reactivation of this parasite. Here we show that a T. gondii gene (named Regulator of Cystogenesis 1; ROCY1) is sufficient for T. gondii bradyzoite formation in vitro and in vivo. ROCY1 encodes an RNA binding protein that has a preference for 3' regulatory regions of hundreds of T. gondii transcripts, and its RNA-binding domains are required to mediate bradyzoite development. Female mice infected with ΔROCY1 parasites have reduced (>90%) cyst burden. While viable parasites can be cultivated from brain tissue for up to 6 months post-infection, chronic brain-resident ΔROCY1 parasites have reduced oral infectivity compared to wild type. Despite clear defects in bradyzoite formation and oral infectivity, ΔROCY1 parasites were able to reactivate with similar timing and magnitude as wild type parasites for up to 5 months post-infection. Therefore while ROCY1 is a critical regulator of the bradyzoite developmental pathway, it is not required for parasite reactivation, raising new questions about the persisting life stage responsible for causing recrudescent disease.
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Affiliation(s)
- Sarah L Sokol-Borrelli
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Sarah M Reilly
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michael J Holmes
- Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, IN, 462022, USA
| | - Stephanie B Orchanian
- Department of Molecular Biology & Biochemistry, University of California, Irvine, CA, USA
| | - Mackenzie D Massmann
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Katherine G Sharp
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Leah F Cabo
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Hisham S Alrubaye
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bruno Martorelli Di Genova
- Department of Microbiology and Molecular Genetics, University of Vermont Larner College of Medicine, Burlington, VT, USA
| | - Melissa B Lodoen
- Department of Molecular Biology & Biochemistry, University of California, Irvine, CA, USA
| | - William J Sullivan
- Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, IN, 462022, USA
| | - Jon P Boyle
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA, USA.
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Xie L, Xing Y, Yang J, Liu M, Cai Y. Toxoplasma gondii Reactivation Aggravating Cardiac Function Impairment in Mice. Pathogens 2023; 12:1025. [PMID: 37623985 PMCID: PMC10458591 DOI: 10.3390/pathogens12081025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 08/05/2023] [Accepted: 08/07/2023] [Indexed: 08/26/2023] Open
Abstract
BACKGROUND Toxoplasma gondii (T. gondii) reactivation is common, especially among immunocompromised individuals, such as AIDS patients. The cardiac involvement associated with toxoplasmosis, however, is usually obscured by neurological deterioration. The aim of this study was to observe the alterations in cardiac functions in various landmark periods after infection and to assess whether reactivation more seriously damages the heart. METHODS We established three infection models in mice using TgCtwh6, a major strain of T. gondii prevalent in China. The groups included an acute group, chronic latent group, and reactivation group. We evaluated the cardiac function impairment via H & E staining, Masson staining, echocardiography, myocardial enzyme profiles, and cardiac troponin, and detected the expression of inflammatory factors and antioxidant factors with Western blotting. Immunofluorescence was used to detect the expression of the macrophage marker F4/80. RESULTS Our results showed that damage to the heart occurred in the acute and reactivation groups. Impaired cardiac function manifested as a decrease in heart rate and a compensatory increase in left ventricular systolic function. Serum levels of cardiac enzymes also increased dramatically. In the chronic phase, myocardial fibrosis developed, diastolic functions became severely impaired, inflammation persisted, and macrophage expression was slightly reduced. Ultimately, reactivation infection exacerbated damage to cardiac function in mice, potentially leading to diastolic heart failure. Macrophages were strongly activated, and myocardial fibrosis was increased. In addition, the antioxidant capacity of the heart was severely affected by the infection. CONCLUSIONS Taken together, these results suggested that the reactivation of T. gondii infection could aggravate injury to the heart, which could be associated with a host-cell-mediated immune response and strong cytokine production by macrophages, thus representing a novel insight into the pathogenic mechanism of toxoplasmosis.
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Affiliation(s)
- Linding Xie
- Department of Health Inspection and Quarantine, School of Public Health, Anhui Medical University, Hefei 230032, China
- Department of Microbiology and Parasitology, the Provincial Laboratory of Pathogen Biology of Anhui, and the Key Laboratory of Zoonoses of Anhui, Anhui Medical University, Hefei 230032, China
| | - Yien Xing
- Department of Health Inspection and Quarantine, School of Public Health, Anhui Medical University, Hefei 230032, China
- Department of Microbiology and Parasitology, the Provincial Laboratory of Pathogen Biology of Anhui, and the Key Laboratory of Zoonoses of Anhui, Anhui Medical University, Hefei 230032, China
| | - Jun Yang
- Department of Health Inspection and Quarantine, School of Public Health, Anhui Medical University, Hefei 230032, China
- Department of Microbiology and Parasitology, the Provincial Laboratory of Pathogen Biology of Anhui, and the Key Laboratory of Zoonoses of Anhui, Anhui Medical University, Hefei 230032, China
| | - Min Liu
- Department of Health Inspection and Quarantine, School of Public Health, Anhui Medical University, Hefei 230032, China
- Department of Microbiology and Parasitology, the Provincial Laboratory of Pathogen Biology of Anhui, and the Key Laboratory of Zoonoses of Anhui, Anhui Medical University, Hefei 230032, China
| | - Yihong Cai
- Department of Health Inspection and Quarantine, School of Public Health, Anhui Medical University, Hefei 230032, China
- Department of Microbiology and Parasitology, the Provincial Laboratory of Pathogen Biology of Anhui, and the Key Laboratory of Zoonoses of Anhui, Anhui Medical University, Hefei 230032, China
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Dupont D, Lin JS, Peyron F, Akaoka H, Wallon M. Chronic Toxoplasma gondii infection and sleep-wake alterations in mice. CNS Neurosci Ther 2021; 27:895-907. [PMID: 34085752 PMCID: PMC8265947 DOI: 10.1111/cns.13650] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/21/2021] [Accepted: 03/24/2021] [Indexed: 11/29/2022] Open
Abstract
AIM Toxoplasma gondii (Tg) is an intracellular parasite infecting more than a third of the human population. Yet, the impact of Tg infection on sleep, a highly sensitive index of brain functions, remains unknown. We designed an experimental mouse model of chronic Tg infection to assess the effects on sleep-wake states. METHODS Mice were infected using cysts of the type II Prugniaud strain. We performed chronic sleep-wake recordings and monitoring as well as EEG power spectral density analysis in order to assess the quantitative and qualitative changes of sleep-wake states. Pharmacological approach was combined to evaluate the direct impact of the infection and inflammation caused by Tg. RESULTS Infected mouse exhibited chronic sleep-wake alterations over months, characterized by a marked increase (>20%) in time spent awake and in cortical EEG θ power density of all sleep-wake states. Meanwhile, slow-wave sleep decreased significantly. These effects were alleviated by an anti-inflammatory treatment using corticosteroid dexamethasone. CONCLUSION We demonstrated for the first time the direct consequences of Tg infection on sleep-wake states. The persistently increased wakefulness and reduced sleep fit with the parasite's strategy to enhance dissemination through host predation and are of significance in understanding the neurodegenerative and neuropsychiatric disorders reported in infected patients.
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Affiliation(s)
- Damien Dupont
- Institut des Agents Infectieux, Parasitologie Mycologie, Hôpital de la Croix-Rousse, Hospices Civils de Lyon, Lyon, France.,Physiologie intégrée du système d'éveil, Faculté de Médecine, Centre de Recherche en Neurosciences de Lyon, INSERM U1028-CNRS UMR 5292, Université Claude Bernard Lyon 1, Lyon, France
| | - Jian-Sheng Lin
- Physiologie intégrée du système d'éveil, Faculté de Médecine, Centre de Recherche en Neurosciences de Lyon, INSERM U1028-CNRS UMR 5292, Université Claude Bernard Lyon 1, Lyon, France
| | - François Peyron
- Institut des Agents Infectieux, Parasitologie Mycologie, Hôpital de la Croix-Rousse, Hospices Civils de Lyon, Lyon, France
| | - Hideo Akaoka
- Physiologie intégrée du système d'éveil, Faculté de Médecine, Centre de Recherche en Neurosciences de Lyon, INSERM U1028-CNRS UMR 5292, Université Claude Bernard Lyon 1, Lyon, France
| | - Martine Wallon
- Institut des Agents Infectieux, Parasitologie Mycologie, Hôpital de la Croix-Rousse, Hospices Civils de Lyon, Lyon, France.,Physiologie intégrée du système d'éveil, Faculté de Médecine, Centre de Recherche en Neurosciences de Lyon, INSERM U1028-CNRS UMR 5292, Université Claude Bernard Lyon 1, Lyon, France
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Abdel-Magied AA, Ghorab DS, Elhenawy AA, Aboulfotouh NI. Immunological, histopathological, and ultrastructural evidence of steroid-induced reactivation of chronic murine toxoplasmosis. Ultrastruct Pathol 2020; 45:28-36. [PMID: 33377812 DOI: 10.1080/01913123.2020.1858213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
We developed a model of steroid-induced reactivation of chronic murine toxoplasmosis to mirror similar effects of steroids or other immunosuppressants in infected humans. Immunological, histopathological, and ultrastructural parameters were reported. Prior to steroid administration, mice were infected with 10 cysts of the Me49 strain of Toxoplasma gondii. Mice were treated with dexamethasone (DXM, 2.5 mg/kg/day in drinking water), alone or combined with Solu-Cortef (SOLU, 50 mg/kg by subcutaneous injection 3 times a week) for 7 weeks or left untreated as control. Histopathological changes and ultrastructural effects of steroids on the course of chronic toxoplasmosis were recorded. By electron microscopy, the brains of infected combined treated mice showed an increase in number of tachyzoites and bradyzoites, degeneration, and necrosis of neural cells and hydropic degeneration besides the observed rupture of toxoplasma cysts releasing free tachyzoites in brain tissue. DXM+SOLU-combined treatment also significantly increased mortality, mean brain cyst count as compared to infected untreated mice (P = .01 and). Moreover, 3/12 (25%) treated animals developed clinical signs of toxoplasmic encephalitis. This simple model of drug-induced reactivation of chronic toxoplasmosis permits investigation of host-parasite interaction and may be used for the evaluation of chemotherapeutics in immunocompromised infected patients.
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Affiliation(s)
| | - Doaa S Ghorab
- Pathology Department, Mansoura University, Mansoura, Egypt
| | - Abeer A Elhenawy
- Medical Parasitology Department, Mansoura University, Mansoura, Egypt
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El-Sayad MH, Hussein NA, Kazem AH, El Geddawi OA, Rizk EM, El-Taweel HA. Temporal expression of Toxoplasma stage-specific genes in brain tissue: coincidence with parasitological and histopathological findings in mice models. Parasitol Res 2020; 119:2299-2307. [PMID: 32476060 DOI: 10.1007/s00436-020-06723-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 05/17/2020] [Indexed: 11/28/2022]
Abstract
In the intermediate hosts, tachyzoites of T. gondii predominate in the acute stage while bradyzoites persist inside tissue cysts with the potential for reactivation. The two stages exhibit different metabolic and antigenic characters. The present study aimed to investigate temporal expression of Toxoplasma SAG1 and BAG1 genes in the brain tissue and the coincident parasitological and histopathological findings in mice models of toxoplasmosis. The study included group A: mice infected with RH strain and sacrificed 7 days post-infection (p.i.); group B: mice infected with RH strain and treated with sulfamethoxazole-trimethoprim (30 mg/kg/day and 150 mg/kg/day respectively) 24 h p.i. until sacrificed at days 5, 10, or 20 post-treatment; group C: mice infected with ME-49 strain and sacrificed at days 7, 27, 47, or 67 p.i; and group D: mice infected with ME-49 strain and received dexamethasone daily starting at day 68 p.i. and scarified at days 6 or 10 post-treatment. All mice were inspected daily for abnormal physical signs. Peritoneal exudate and brain homogenate were examined for detection of Toxoplasma stages. Brain sections were examined histopathologically. SAG1 and BAG1 gene expression was evaluated using reverse transcription real-time polymerase chain reaction and the ΔΔCt method. Results revealed that marked BAG1 upregulation is consistent with detection of Toxoplasma cysts and degenerative changes while predominance of tachyzoites and inflammatory infiltrate is compatible with SAG1 upregulation. The study sheds light on the potential for using stage-specific gene expression pattern as markers for evaluation of toxoplasmosis disease progression in clinical settings.
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Affiliation(s)
- Mona H El-Sayad
- Parasitology Department, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Neveen A Hussein
- Applied Medical Chemistry Department, Alexandria University, Alexandria, Egypt
| | - A H Kazem
- Pathology Department, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Omnya A El Geddawi
- Parasitology Department, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Enas M Rizk
- Parasitology Department, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Hend A El-Taweel
- Parasitology Department, Medical Research Institute, Alexandria University, Alexandria, Egypt.
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Schlüter D, Barragan A. Advances and Challenges in Understanding Cerebral Toxoplasmosis. Front Immunol 2019; 10:242. [PMID: 30873157 PMCID: PMC6401564 DOI: 10.3389/fimmu.2019.00242] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 01/28/2019] [Indexed: 11/22/2022] Open
Abstract
Toxoplasma gondii is a widespread parasitic pathogen that infects over one third of the global human population. The parasite invades and chronically persists in the central nervous system (CNS) of the infected host. Parasite spread and persistence is intimately linked to an ensuing immune response, which does not only limit parasite-induced damage but also may facilitate dissemination and induce parasite-associated immunopathology. Here, we discuss various aspects of toxoplasmosis where knowledge is scarce or controversial and, the recent advances in the understanding of the delicate interplay of T. gondii with the immune system in experimental and clinical settings. This includes mechanisms for parasite passage from the circulation into the brain parenchyma across the blood-brain barrier during primary acute infection. Later, as chronic latent infection sets in with control of the parasite in the brain parenchyma, the roles of the inflammatory response and of immune cell responses in this phase of the disease are discussed. Additionally, the function of brain resident cell populations is delineated, i.e., how neurons, astrocytes and microglia serve both as target cells for the parasite but also actively contribute to the immune response. As the infection can reactivate in the CNS of immune-compromised individuals, we bring up the immunopathogenesis of reactivated toxoplasmosis, including the special case of congenital CNS manifestations. The relevance, advantages and limitations of rodent infection models for the understanding of human cerebral toxoplasmosis are discussed. Finally, this review pinpoints questions that may represent challenges to experimental and clinical science with respect to improved diagnostics, pharmacological treatments and immunotherapies.
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Affiliation(s)
- Dirk Schlüter
- Hannover Medical School, Institute of Medical Microbiology and Hospital Epidemiology, Hannover, Germany
| | - Antonio Barragan
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
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Sánchez-Sánchez R, Ferre I, Regidor-Cerrillo J, Gutiérrez-Expósito D, Ferrer LM, Arteche-Villasol N, Moreno-Gonzalo J, Müller J, Aguado-Martínez A, Pérez V, Hemphill A, Ortega-Mora LM, Benavides J. Virulence in Mice of a Toxoplasma gondii Type II Isolate Does Not Correlate With the Outcome of Experimental Infection in Pregnant Sheep. Front Cell Infect Microbiol 2019; 8:436. [PMID: 30662874 PMCID: PMC6328472 DOI: 10.3389/fcimb.2018.00436] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 12/10/2018] [Indexed: 11/13/2022] Open
Abstract
Toxoplasma gondii is an apicomplexan parasite that infects almost all warm-blooded animals. Little is known about how the parasite virulence in mice extrapolates to other relevant hosts. In the current study, in vitro phenotype and in vivo behavior in mice and sheep of a type II T. gondii isolate (TgShSp1) were compared with the reference type II T. gondii isolate (TgME49). The results of in vitro assays and the intraperitoneal inoculation of tachyzoites in mice indicated an enhanced virulence for the laboratory isolate, TgME49, compared to the recently obtained TgShSp1 isolate. TgShSp1 proliferated at a slower rate and had delayed lysis plaque formation compared to TgME49, but it formed more cyst-like structures in vitro. No mortality was observed in adult mice after infection with 1–105 tachyzoites intraperitoneally or with 25–2,000 oocysts orally of TgShSp1. In sheep orally challenged with oocysts, TgME49 infection resulted in sporadically higher rectal temperatures and higher parasite load in cotyledons from ewes that gave birth and brain tissues of the respective lambs, but no differences between these two isolates were found on fetal/lamb mortality or lesions and number of T. gondii-positive lambs. The congenital infection after challenge at mid-pregnancy with TgShSp1, measured as offspring mortality and vertical transmission, was different depending on the challenged host. In mice, mortality in 50% of the pups was observed when a dam was challenged with a high oocyst dose (500 TgShSp1 oocysts), whereas in sheep infected with the same dose of oocysts, mortality occurred in all fetuses. Likewise, mortality of 9 and 27% of the pups was observed in mice after infection with 100 and 25 TgShSp1 oocysts, respectively, while in sheep, infection with 50 and 10 TgShSp1 oocysts triggered mortality in 68 and 66% of the fetuses/lambs. Differences in vertical transmission in the surviving offspring were only found with the lower oocyst doses (100% after infection with 10 TgShSp1 oocysts in sheep and only 37% in mice after infection with 25 TgShSp1 oocysts). In conclusion, virulence in mice of T. gondii type II isolates may not be a good indicator to predict the outcome of infection in pregnant sheep.
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Affiliation(s)
- Roberto Sánchez-Sánchez
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain
| | - Ignacio Ferre
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain
| | - Javier Regidor-Cerrillo
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain
| | | | - Luis Miguel Ferrer
- Departamento de Patología Animal, Facultad de Veterinaria, University of Zaragoza, Zaragoza, Spain
| | | | - Javier Moreno-Gonzalo
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain
| | - Joachim Müller
- Vetsuisse Faculty, Institute of Parasitology, University of Bern, Bern, Switzerland
| | | | - Valentín Pérez
- Instituto de Ganadería de Montaña (CSIC-Universidad de León), León, Spain
| | - Andrew Hemphill
- Vetsuisse Faculty, Institute of Parasitology, University of Bern, Bern, Switzerland
| | - Luis Miguel Ortega-Mora
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain
| | - Julio Benavides
- Instituto de Ganadería de Montaña (CSIC-Universidad de León), León, Spain
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Treatment of Toxoplasmosis: Historical Perspective, Animal Models, and Current Clinical Practice. Clin Microbiol Rev 2018; 31:31/4/e00057-17. [PMID: 30209035 DOI: 10.1128/cmr.00057-17] [Citation(s) in RCA: 240] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Primary Toxoplasma gondii infection is usually subclinical, but cervical lymphadenopathy or ocular disease can be present in some patients. Active infection is characterized by tachyzoites, while tissue cysts characterize latent disease. Infection in the fetus and in immunocompromised patients can cause devastating disease. The combination of pyrimethamine and sulfadiazine (pyr-sulf), targeting the active stage of the infection, is the current gold standard for treating toxoplasmosis, but failure rates remain significant. Although other regimens are available, including pyrimethamine in combination with clindamycin, atovaquone, clarithromycin, or azithromycin or monotherapy with trimethoprim-sulfamethoxazole (TMP-SMX) or atovaquone, none have been found to be superior to pyr-sulf, and no regimen is active against the latent stage of the infection. Furthermore, the efficacy of these regimens against ocular disease remains uncertain. In multiple studies, systematic screening for Toxoplasma infection during gestation, followed by treatment with spiramycin for acute maternal infections and with pyr-sulf for those with established fetal infection, has been shown to be effective at preventing vertical transmission and minimizing the severity of congenital toxoplasmosis (CT). Despite significant progress in treating human disease, there is a strong impetus to develop novel therapeutics for both the acute and latent forms of the infection. Here we present an overview of toxoplasmosis treatment in humans and in animal models. Additional research is needed to identify novel drugs by use of innovative high-throughput screening technologies and to improve experimental models to reflect human disease. Such advances will pave the way for lead candidates to be tested in thoroughly designed clinical trials in defined patient populations.
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Mokua Mose J, Muchina Kamau D, Kagira JM, Maina N, Ngotho M, Njuguna A, Karanja SM. Development of Neurological Mouse Model for Toxoplasmosis Using Toxoplasma gondii Isolated from Chicken in Kenya. PATHOLOGY RESEARCH INTERNATIONAL 2017; 2017:4302459. [PMID: 28630781 PMCID: PMC5463144 DOI: 10.1155/2017/4302459] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 04/19/2017] [Indexed: 11/17/2022]
Abstract
Animal models for the toxoplasmosis are scarce and have limitations. In this study, a neurological mouse model was developed in BALB/c mice infected intraperitoneally with 15 cysts of a Toxoplasma gondii isolate. The mice were monitored for 42 days and euthanized at different time points. Another group of mice were orally treated with dexamethasone (DXM: 2.66 mg/kg daily, 5.32 mg/kg daily) at 42 days after infection and monitored for a further 42 days. A mortality rate of 15% and 28.6% was observed in mice given 2.66 mg/kg/day and 5.32 mg/kg/day of DXM, respectively. The mean cyst numbers in the brain of DXM treated mice increased up to twofold compared with chronically infected untreated mice. Infections up to 42 days were associated with an increase in both IgM and IgG levels but following dexamethasone treatment, IgM levels declined but IgG levels continued on rising. The brain of toxoplasmosis infected mice showed mononuclear cellular infiltrations, neuronal necrosis, and cuffing. The severity of pathology was higher in mice treated with dexamethasone compared to the positive control groups. The findings of this study demonstrate that DXM-induced reactivation of chronic toxoplasmosis may be a useful development of laboratory animal model in outbred mice used for in vivo studies.
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Affiliation(s)
- John Mokua Mose
- Department of Medical Laboratory Science, School of Medicine and Health Sciences, Kenya Methodist University, P.O. Box 45240-00100, Nairobi, Kenya
- Department of Public Health, Jomo Kenyatta University of Agriculture and Technology (JKUAT), P.O. Box 62000-00200, Nairobi, Kenya
| | - David Muchina Kamau
- Department of Public Health, Jomo Kenyatta University of Agriculture and Technology (JKUAT), P.O. Box 62000-00200, Nairobi, Kenya
| | - John Maina Kagira
- Department of Animal Sciences, Jomo Kenyatta University of Agriculture and Technology (JKUAT), P.O. Box 62000-00200, Nairobi, Kenya
| | - Naomi Maina
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology (JKUAT), P.O. Box 62000-00200, Nairobi, Kenya
| | - Maina Ngotho
- Department of Animal Health & Production, Mount Kenya University, P.O. Box 342-01000, Thika 342-01000, Kenya
| | - Adele Njuguna
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology (JKUAT), P.O. Box 62000-00200, Nairobi, Kenya
| | - Simon Muturi Karanja
- Department of Public Health, Jomo Kenyatta University of Agriculture and Technology (JKUAT), P.O. Box 62000-00200, Nairobi, Kenya
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King MD, Lindsay DS, Ehrich MF, Nagarkatti M. Effect of 2,3,7,8-Tetrachloro-di-benzo-p-dioxin on T Cell Subpopulations in the Thymus and Spleen of Mice with Chronic Toxoplasma gondii Infection. Int J Toxicol 2016. [DOI: 10.1080/10915810050178770] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
In the current study, the effect of exposure to the environmental pollutant, 2,3,7,8-tetrachloro-di-benzo- p-dioxin (TCDD), on mice having chronic infection with Toxoplasma gondii was investigated. For this purpose, four groups of mice were used—mice treated with vehicle, mice treated with TCDD alone, mice infected with T. gondii alone, and mice receiving a combination of TCDD treatment and T. gondii infection. Histological examination and tissue cyst enumeration were performed to indicate the level of infection of the brain. The immune status was studied by enumerating the cellularity as well as the percentages and absolute numbers of the lymphocyte subsets based on the expression of CD4 and CD8 markers in the thymus and spleen. Our studies demonstrated that there was a significant decrease in the total number of thymocytes in TCDD-treated mice that were either uninfected or infected with T. gondii when compared to vehicle controls. However, there was no significant difference observed in thymic cellularity in mice that were infected with T. gondii alone when compared to the uninfected vehicle controls. In addition, the ratio and the total numbers of CD4+, CD8+, CD4–CD8–(double negative, DN) and CD4+CD8+ (double positive, DP) T cell subsets in the thymus from various groups were determined. There was no change in the percentages of T cell subsets in TCDD-treated mice or T. gondii-infected mice when compared to the vehicle controls. However, there was a decrease in the percentage of DPT cells and an increase in the DN and CD8+ T cells in mice that received a combination of TCDD-treatment and T. gondii infection when compared to mice receiving the vehicle or TCDD-treatment alone or infection with T. gondii alone. There was also a decrease in the absolute numbers of the DP and CD4+ T cells and an increase in the CD8+ T cells in the thymus of mice receiving the combination of TCDD-treatment and T. gondii infection when compared to vehicle controls. The splenic cellularity as well as the percentage and absolute numbers of the CD4+ and CD8+ T cell subsets and the non-T cells were not altered in all the groups tested. The natural history of T. gondii infection was not altered following TCDD treatment as demonstrated by no significant differences in brain lesion scores and the number of tissue cysts in the brains of these mice.
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Affiliation(s)
- Marquea D. King
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
| | - David S. Lindsay
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
| | - Marion F. Ehrich
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
| | - Mitzi Nagarkatti
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
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Hillman AE, Lymbery AJ, Thompson RA. Is Toxoplasma gondii a threat to the conservation of free-ranging Australian marsupial populations? Int J Parasitol Parasites Wildl 2016; 5:17-27. [PMID: 27141439 PMCID: PMC4840267 DOI: 10.1016/j.ijppaw.2015.12.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 12/07/2015] [Accepted: 12/11/2015] [Indexed: 11/25/2022]
Abstract
It has often been asserted that Australian marsupial species are particularly susceptible to Toxoplasma gondii infection and to clinical toxoplasmosis following infection. This implicates T. gondii as a potential threat to marsupial population viability, and contrasts to what is known of T. gondii in populations of several other host species. We reviewed the literature, and found a lack of scientifically robust evidence addressing the occurrence of T. gondii infection in free-ranging populations of Australian marsupial species, and the impacts of the infection on population health. Key limitations included a lack of studies in free-ranging marsupial populations, study findings susceptible to substantial chance influences, and selection, misclassification and confounding biases. The lack of scientifically robust data available on this topic indicates that assertions that free-ranging populations of Australian marsupials are particularly susceptible to T. gondii infection and to toxoplasmosis are premature. The threat of T. gondii to the viability of free-ranging marsupial populations should therefore be regarded, at this stage, as a hypothesis.
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Mahmoud ME, Ihara F, Fereig RM, Nishimura M, Nishikawa Y. Induction of depression-related behaviors by reactivation of chronic Toxoplasma gondii infection in mice. Behav Brain Res 2016; 298:125-33. [DOI: 10.1016/j.bbr.2015.11.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 11/02/2015] [Accepted: 11/04/2015] [Indexed: 12/25/2022]
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AMA1-deficient Toxoplasma gondii parasites transiently colonize mice and trigger an innate immune response that leads to long-lasting protective immunity. Infect Immun 2015; 83:2475-86. [PMID: 25847964 DOI: 10.1128/iai.02606-14] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 03/25/2015] [Indexed: 11/20/2022] Open
Abstract
The apical membrane antigen 1 (AMA1) protein was believed to be essential for the perpetuation of two Apicomplexa parasite genera, Plasmodium and Toxoplasma, until we genetically engineered viable parasites lacking AMA1. The reduction in invasiveness of the Toxoplasma gondii RH-AMA1 knockout (RH-AMA1(KO)) tachyzoite population, in vitro, raised key questions about the outcome associated with these tachyzoites once inoculated in the peritoneal cavity of mice. In this study, we used AMNIS technology to simultaneously quantify and image the parasitic process driven by AMA1(KO) tachyzoites. We report their ability to colonize and multiply in mesothelial cells and in both resident and recruited leukocytes. While the RH-AMA1(KO) population amplification is rapidly lethal in immunocompromised mice, it is controlled in immunocompetent hosts, where immune cells in combination sense parasites and secrete proinflammatory cytokines. This innate response further leads to a long-lasting status immunoprotective against a secondary challenge by high inocula of the homologous type I or a distinct type II T. gondii genotypes. While AMA1 is definitively not an essential protein for tachyzoite entry and multiplication in host cells, it clearly assists the expansion of parasite population in vivo.
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15
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Toxoplasma gondii 70 kDa heat shock protein: systemic detection is associated with the death of the parasites by the immune response and its increased expression in the brain is associated with parasite replication. PLoS One 2014; 9:e96527. [PMID: 24801069 PMCID: PMC4011789 DOI: 10.1371/journal.pone.0096527] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 04/07/2014] [Indexed: 11/19/2022] Open
Abstract
The heat shock protein of Toxoplasma gondii (TgHSP70) is a parasite virulence factor that is expressed during T. gondii stage conversion. To verify the effect of dexamethasone (DXM)-induced infection reactivation in the TgHSP70-specific humoral immune response and the presence of the protein in the mouse brain, we produced recombinant TgHSP70 and anti-TgHSP70 IgY antibodies to detect the protein, the specific antibody and levels of immune complexes (ICs) systemically, as well as the protein in the brain of resistant (BALB/c) and susceptible (C57BL/6) mice. It was observed higher TgHSP70-specific antibody titers in serum samples of BALB/c compared with C57BL/6 mice. However, the susceptible mice presented the highest levels of TgHSP70 systemically and no detection of specific ICs. The DXM treatment induced increased parasitism and lower inflammatory changes in the brain of C57BL/6, but did not interfere with the cerebral parasitism in BALB/c mice. Additionally, DXM treatment decreased the serological TgHSP70 concentration in both mouse lineages. C57BL/6 mice presented high expression of TgHSP70 in the brain with the progression of infection and under DXM treatment. Taken together, these data indicate that the TgHSP70 release into the bloodstream depends on the death of the parasites mediated by the host immune response, whereas the increased TgHSP70 expression in the brain depends on the multiplication rate of the parasite.
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Bottari NB, Tonin AA, Fighera R, Flores MM, França RT, Camillo G, Toscan G, Vogel FSF, Sangoi MB, Bochi GV, Moresco RN, Lopes STA, Da Silva AS. Neospora caninum and Toxoplasma gondii: relationship between hepatic lesions, cytological and biochemical analysis of the cavitary liquid during the acute phase of the diseases in experimental models. Exp Parasitol 2013; 136:68-73. [PMID: 24275558 DOI: 10.1016/j.exppara.2013.11.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Revised: 11/12/2013] [Accepted: 11/13/2013] [Indexed: 10/26/2022]
Abstract
The objective of this study was to evaluate the pathogenesis of ascites in mice infected with Toxoplasma gondii and gerbils infected with Neospora caninum during the acute phase disease. For that, 12 gerbils [Experiment I: not infected/control (n=6) and infected (n=6)] and 12 mice [Experiment II: control (n=6) and infected (n=6)] were used. Infected gerbils and mice showed marked ascites on days 5-7 post-infection (PI), while the not-infected animals had not ascites. Peritoneal liquid was collected from the all mice with uninfected animals receiving 1.5mL of saline solution into their abdominal cavity, allowing the recovery of cavity liquid. As a result, it was possible to observe differences in physics, chemistry and cytological analysis of the fluid cavity of animals infected with N. caninum and T. gondii, when they were compared with uninfected animals, as well as between animals experimentally infected. Additionally both, N. caninum and T gondii, caused an increase in the levels of nitric oxide (NOx-nitrate/nitrite), protein oxidation (AOPP) and lipid peroxidation (TBARS), while serum total protein and albumin were reduced in infected gerbils and mice. Gerbils infected with N. caninum showed multiple large cells with multilobulated nucleus, lytic necrosis and abundant amount of eosinophilic cytoplasm into the hepatic parenchyma. By the other hand, mice infected with T. gondii developed myriad foci of lytic necrosis combined with tachyzoites and cysts containing bradyzoites in liver. Both experimental models for N. caninum and T. gondii showed inflammatory foci and tachyzoites the peritoneum, which could be a major cause of ascites. Toxoplasmosis and neosporosis were able to cause clinical signs in experimental models with similar alterations in peritoneal fluid; however the toxoplasmosis histological changes were much more evident. Therefore, the pathogenesis of ascites appears to be directly related to liver damage, which strongly suggests alteration in the normal production of proteins as observed in this study, along with peritonitis.
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Affiliation(s)
- Nathieli B Bottari
- Program of Postgraduate in Biochemical Toxicology, Universidade Federal de Santa Maria, Brazil
| | - Alexandre A Tonin
- Department of Small Animals, Universidade Federal de Santa Maria, Brazil
| | - Rafael Fighera
- Department of Pathology, Universidade Federal de Santa Maria, Brazil
| | - Mariana M Flores
- Department of Pathology, Universidade Federal de Santa Maria, Brazil
| | - Raqueli T França
- Department of Small Animals, Universidade Federal de Santa Maria, Brazil
| | - Giovana Camillo
- Department of Preventive Medicine Veterinary, Universidade Federal de Santa Maria, Brazil
| | - Gustavo Toscan
- Department of Preventive Medicine Veterinary, Universidade Federal de Santa Maria, Brazil
| | - Fernanda S F Vogel
- Department of Preventive Medicine Veterinary, Universidade Federal de Santa Maria, Brazil
| | - Manuela B Sangoi
- Department of Clinical and Toxicological Analysis, Universidade Federal de Santa Maria, Brazil
| | - Guilherme V Bochi
- Department of Clinical and Toxicological Analysis, Universidade Federal de Santa Maria, Brazil
| | - Rafael N Moresco
- Department of Clinical and Toxicological Analysis, Universidade Federal de Santa Maria, Brazil
| | - Sonia T A Lopes
- Department of Small Animals, Universidade Federal de Santa Maria, Brazil
| | - Aleksandro S Da Silva
- Program of Postgraduate in Biochemical Toxicology, Universidade Federal de Santa Maria, Brazil; Department of Animal Science, Universidade do Estado de Santa Catarina, Brazil.
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17
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Dehkordi FS, Borujeni MRH, Rahimi E, Abdizadeh R. Detection of Toxoplasma gondii in raw caprine, ovine, buffalo, bovine, and camel milk using cell cultivation, cat bioassay, capture ELISA, and PCR methods in Iran. Foodborne Pathog Dis 2013; 10:120-5. [PMID: 23441913 DOI: 10.1089/fpd.2012.1311] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
This study was conducted to determine the presence of Toxoplasma gondii in animal milk samples in Iran. From a total of 395 dairy herds in three provinces of Iran, 66 bovine, 58 ovine, 54 caprine, 33 buffalo, and 30 camel herds were studied, and from these parts of Iran, 200 bovine, 185 ovine, 180 caprine, 164 buffalo, and 160 camel milk samples were collected from various seasons. Samples were tested for Toxoplasma gondii by cell line culture, enzyme-linked immunosorbent assay (ELISA), and polymerase chain reaction (PCR) technique. Only the results of cell line cultivation were confirmed by bioassay in cat. Results indicated that all herds were infected with Toxoplasma gondii. The culture method showed that 51 out of 889 milk samples (5.73%) were positive for Toxoplasma gondii, and all 51 positive culture results were positive with bioassay in cat. The Fars province had the highest prevalence of Toxoplasma gondii (6.84%). The ELISA test showed that 41 milk samples (4.61%) were positive for the presence of Toxoplasma gondii, while the PCR showed that 46 milk samples were positive for Toxoplasma gondii. The results showed higher sensitivity of PCR and higher specificity of ELISA. Caprine had the highest (10%) and camel had the lowest (3.12%) prevalence rate of parasite. The summer season had the highest (76.47%) but winter (3.92) had the lowest incidence of Toxoplasma gondii. This study is the first prevalence report of direct detection of Toxoplasma gondii in animal milk samples in Iran.
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18
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Relationship between butyrylcholinesterase activity and liver injury in mice acute infected with Toxoplasma gondii. Pathol Res Pract 2013; 209:95-8. [PMID: 23313104 DOI: 10.1016/j.prp.2012.10.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2012] [Revised: 10/03/2012] [Accepted: 10/24/2012] [Indexed: 10/27/2022]
Abstract
This study aimed to investigate the butyrylcholinesterase (BChE) activity in mice experimentally infected with Toxoplasma gondii during the acute phase. Twenty mice were divided in two groups with 10 animals each: group A was composed of uninfected mice while group B was formed by rodents infected with T. gondii. Five days after infection, blood was collected and serum separated, and fragments of liver and brain were obtained. In serum and liver homogenate was noted a significant reduction (P<0.05) in BChE activity in infected mice when compared with uninfected ones. In serum was observed an increase in the activity of alanine aminotransferase and urea, associated with reduction in alkaline phosphatase activity and in the levels of total protein and albumin. Histologically, there were foci of necrosis and parasites in the forms of tachyzoites and cysts, with bradyzoites in liver samples of infected animals. Based on these results, we conclude that toxoplasmosis reduces BChE activity in mice, and this alteration is probably related to the liver damage caused by the parasitism. Therefore, this enzymatic alteration can directly contribute to the pathogenesis of the disease.
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19
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Selseleh M, Modarressi MH, Mohebali M, Shojaee S, Eshragian MR, Selseleh M, Azizi E, Keshavarz H. Real-time RT-PCR on SAG1 and BAG1 gene expression during stage conversion in immunosuppressed mice infected with Toxoplasma gondii Tehran strain. THE KOREAN JOURNAL OF PARASITOLOGY 2012; 50:199-205. [PMID: 22949746 PMCID: PMC3428564 DOI: 10.3347/kjp.2012.50.3.199] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 04/13/2012] [Accepted: 04/14/2012] [Indexed: 11/23/2022]
Abstract
Toxoplasmic encephalitis is caused by reactivation of bradyzoites to rapidly dividing tachyzoites of the apicomplexan parasite Toxoplasma gondii in immunocompromised hosts. Diagnosis of this life-threatening disease is problematic, because it is difficult to discriminate between these 2 stages. Toxoplasma PCR assays using gDNA as a template have been unable to discriminate between an increase or decrease in SAG1 and BAG1 expression between the active tachyzoite stage and the latent bradyzoite stage. In the present study, real-time RT-PCR assay was used to detect the expression of bradyzoite (BAG1)- and tachyzoite-specific genes (SAG1) during bradyzoite/tachyzoite stage conversion in mice infected with T. gondii Tehran strain after dexamethasone sodium phosphate (DXM) administration. The conversion reaction was observed in the lungs and brain tissues of experimental mice, indicated by SAG1 expression at day 6 after DXM administration, and continued until day 14. Bradyzoites were also detected in both organs throughout the study; however, it decreased at day 14 significantly. It is suggested that during the reactivation period, bradyzoites not only escape from the cysts and reinvade neighboring cells as tachyzoites, but also converted to new bradyzoites. In summary, the real-time RT-PCR assay provided a reliable, fast, and quantitative way of detecting T. gondii reactivation in an animal model. Thus, this method may be useful for diagnosing stage conversion in clinical specimens of immunocompromised patients (HIV or transplant patients) for early identification of tachyzoite-bradyzoite stage conversion.
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Affiliation(s)
- Monavar Selseleh
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
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20
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Sullivan WJ, Jeffers V. Mechanisms of Toxoplasma gondii persistence and latency. FEMS Microbiol Rev 2012; 36:717-33. [PMID: 22091606 PMCID: PMC3319474 DOI: 10.1111/j.1574-6976.2011.00305.x] [Citation(s) in RCA: 169] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 08/22/2011] [Accepted: 08/25/2011] [Indexed: 11/28/2022] Open
Abstract
Toxoplasma gondii is an obligate intracellular protozoan parasite that causes opportunistic disease, particularly in immunocompromised individuals. Central to its transmission and pathogenesis is the ability of the proliferative stage (tachyzoite) to convert into latent tissue cysts (bradyzoites). Encystment allows Toxoplasma to persist in the host and affords the parasite a unique opportunity to spread to new hosts without proceeding through its sexual stage, which is restricted to felids. Bradyzoite tissue cysts can cause reactivated toxoplasmosis if host immunity becomes impaired. A greater understanding of the molecular mechanisms orchestrating bradyzoite development is needed to better manage the disease. Here, we will review key studies that have contributed to our knowledge about this persistent form of the parasite and how to study it, with a focus on how cellular stress can signal for the reprogramming of gene expression needed during bradyzoite development.
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Affiliation(s)
- William J Sullivan
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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21
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Silva RCD, Silva AVD, Langoni H. Recrudescence of Toxoplasma gondii infection in chronically infected rats (Rattus norvegicus). Exp Parasitol 2010; 125:409-12. [DOI: 10.1016/j.exppara.2010.04.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Revised: 03/26/2010] [Accepted: 04/12/2010] [Indexed: 11/28/2022]
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Mahittikorn A, Wickert H, Sukthana Y. Toxoplasma gondii: Simple duplex RT-PCR assay for detecting SAG1 and BAG1 genes during stage conversion in immunosuppressed mice. Exp Parasitol 2009; 124:225-31. [PMID: 19854173 DOI: 10.1016/j.exppara.2009.10.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2009] [Revised: 08/19/2009] [Accepted: 10/16/2009] [Indexed: 11/25/2022]
Abstract
Toxoplasmic encephalitis (TE) is caused by reactivation of dormant bradyzoites into rapidly dividing tachyzoites of the apicomplexan parasite Toxoplasma gondii in immune-compromised hosts. Diagnosis of this life-threatening disease is complicated, since it is difficult to distinguish between these two stages. It is, therefore, mainly based on a test positive for T. gondii antibodies, and specific clinical symptoms. We developed a duplex RT-PCR to detect the expression of bradyzoite (BAG1) and tachyzoite (SAG1) specific genes simultaneously during tachyzoite/bradyzoite stage conversion. The conversion reaction was observed in many organs of experimental mice, indicated by tachyzoites in the cerebrum, cerebellum, heart and lung, beginning in week 1 after the suppression period, and continuing until the end. Bradyzoites were also detected in nearly all organs throughout the study, suggesting that during the reactivation period, bradyzoites not only escape from cysts and reinvade neighboring cells as tachyzoites, but are also driven into developing new bradyzoites. The results of our study show that duplex RT-PCR is an easy, rapid, sensitive, and reproducible method, which is particularly valuable when numerous samples must be analyzed. This technique may usefully serve as an alternate tool for diagnosing TE in severely immunocompromised patients.
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Affiliation(s)
- Aongart Mahittikorn
- Department of Protozoology, Faculty of Tropical Medicine, Mahidol University, 10400 Bangkok, Thailand
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Al-Qassab S, Reichel MP, Su C, Jenkins D, Hall C, Windsor PA, Dubey J, Ellis J. Isolation of Toxoplasma gondii from the brain of a dog in Australia and its biological and molecular characterization. Vet Parasitol 2009; 164:335-9. [DOI: 10.1016/j.vetpar.2009.05.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 05/02/2009] [Accepted: 05/06/2009] [Indexed: 10/20/2022]
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Dellacasa-Lindberg I, Hitziger N, Barragan A. Localized recrudescence of Toxoplasma infections in the central nervous system of immunocompromised mice assessed by in vivo bioluminescence imaging. Microbes Infect 2007; 9:1291-8. [PMID: 17897859 DOI: 10.1016/j.micinf.2007.06.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Revised: 05/21/2007] [Accepted: 06/04/2007] [Indexed: 10/23/2022]
Abstract
Reactivation of infection in the central nervous system (CNS) with the opportunistic parasite Toxoplasma gondii is a major concern in chronically infected immunocompromised individuals. Yet, the pathophysiology associated with recrudescence of infection remains poorly characterized. The onset of acute reactivated Toxoplasma encephalitis in the murine model was assessed using bioluminescence imaging as a spatio-temporal indicator. An uneven distribution of recrudescence of infection in the CNS was found. Foci of recrudescence after immunosuppression were most commonly located in frontal and parietal cortex, whereas little infection was found in the cerebellum. Recrudescence was also more common in grey matter than in white matter. Pathology was exacerbated in mice deficient in interferon gamma receptors (IFN gamma R(-/-)) corroborating the importance of interferon gamma (IFN gamma) for control of CNS infection. Analysis of parasitic foci identified abundant leukocyte infiltration (CD45+, CD4+, CD8+, F4/80+ cells) in the vicinity of replicating parasites and microvasculature. This is the first report that addresses the suborganic localization of acute Toxoplasma encephalitis in the murine model. Collectively, the findings suggest that the localization of reactivation foci in the CNS, in conjunction with immune responses, influences the outcome of acute reactivated Toxoplasma encephalitis.
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Affiliation(s)
- Isabel Dellacasa-Lindberg
- Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
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25
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Kang KN, Choi IU, Shin DW, Lee YH. Cytokine and antibody responses of reactivated murine toxoplasmosis upon administration of dexamathasone. THE KOREAN JOURNAL OF PARASITOLOGY 2006; 44:209-19. [PMID: 16969058 PMCID: PMC2532666 DOI: 10.3347/kjp.2006.44.3.209] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Toxoplasma gondii has been shown to result in life-threatening encephalitis in immunocompromised patients after reactivation of dormant parasites. In order to obtain information on immune responses related to this phenomenon, BALB/c mice were infected with 25 cysts of the 76K strain of T. gondii, then, treated orally with dexamethasone (Toxo/Dexa-treated group) in order to reactivate the chronic toxoplasmosis. None of the T. gondii-infected mice died during the experimental periods, whereas the Toxo/Dexa-treated mice evidenced a significant attenuation of survival periods. Toxoplasma-specific IgG2a, IgA and IgM titers in sera were significantly depressed in the Toxo/Dexa-treated mice; however, the IgG1 sera titers were similar to those seen in the Toxoplasma-infected mice. The percentages of CD4+ and CD8 alpha + T cells in the Toxo/Dexa-treated mice were significantly reduced 2 weeks after dexamethasone treatment. IFN-gamma and IL-10 production levels in the Toxo/Dexa-treated mice were depressed significantly, whereas IL-4 production was increased temporarily. The expression levels of the Toxoplasma-specific P30 and B1 genes were found to have been increased in the Toxo/Dexa-treated mice in comparison with the Toxoplasmainfected mice. Collectively, the findings of this study demonstrate that reactivation of murine toxoplasmosis as the result of dexamethasone treatment induced a depression in Th1 immune responses, whereas Th2 immune responses were not significantly influenced.
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Affiliation(s)
- Ki-Nam Kang
- Department of Infection Biology, College of Medicine, Chungnam National University, Daejeon, Korea
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Abstract
A large Wisconsin mink (Mustela vison) farm experienced an outbreak of toxoplasmosis in the spring of 1999 following an outbreak of canine distemper during the previous fall. Major clinical signs for pregnant females included reduced feed consumption, abortions, and stillborn kits; kits < or =3 weeks old experienced ataxia and mortality. Of 7,800 females, 1,976 (26%) lost their entire litter either from abortion or neonatal mortality. Kit mortality from 7 days to 3 weeks of age was 3,300, and overall kit mortality attributed to the toxoplasmosis outbreak was 10,408. Six neonatal mink kits, 12 3-week-old kits, and 2 adult female mink were submitted to the University of Minnesota Veterinary Diagnostic Laboratory for diagnostic workup. Gross postmortem lesions were limited to empty stomachs (12 of 12 kits) and pale livers (4 of 12 kits) for the 3-week-old kits. Major microscopic lesions included interstitial pneumonia, encephalitis, encephalomalacia, and myocarditis. Toxoplasmosis was diagnosed by microscopic lesions, microscopic lesion distribution, and the detection of Toxoplasma gondii tachyzoites by immunohistochemistry. This is the first detailed report of an outbreak of toxoplasmosis in mink in the United States.
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Affiliation(s)
- R K Frank
- Department of Veterinary Diagnostic Medicine, University of Minnesota, St. Paul 55108, USA
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Dubey JP, Lindsay DS, Speer CA. Structures of Toxoplasma gondii tachyzoites, bradyzoites, and sporozoites and biology and development of tissue cysts. Clin Microbiol Rev 1998; 11:267-99. [PMID: 9564564 PMCID: PMC106833 DOI: 10.1128/cmr.11.2.267] [Citation(s) in RCA: 683] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Infections by the protozoan parasite Toxoplasma gondii are widely prevalent world-wide in animals and humans. This paper reviews the life cycle; the structure of tachyzoites, bradyzoites, oocysts, sporocysts, sporozoites and enteroepithelial stages of T. gondii; and the mode of penetration of T. gondii. The review provides a detailed account of the biology of tissue cysts and bradyzoites including in vivo and in vitro development, methods of separation from host tissue, tissue cyst rupture, and relapse. The mechanism of in vivo and in vitro stage conversion from sporozoites to tachyzoites to bradyzoites and from bradyzoites to tachyzoites to bradyzoites is also discussed.
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Affiliation(s)
- J P Dubey
- Parasite Biology and Epidemiology Laboratory, USDA Agricultural Research Service, Beltsville, Maryland 20705-2350, USA.
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