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Fadel EF, EL-Hady HA, Ahmed AM, Tolba MEM. Molecular diagnosis of human toxoplasmosis: the state of the art. J Parasit Dis 2024; 48:201-216. [PMID: 38840888 PMCID: PMC11147977 DOI: 10.1007/s12639-024-01667-1] [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: 06/15/2023] [Accepted: 03/23/2024] [Indexed: 06/07/2024] Open
Abstract
Toxoplasma gondii (T. gondii) is an obligate intracellular apicomplexan protozoan that causes toxoplasmosis. Approximately one-third of the world's population is currently T. gondii-seropositive. Although most infections are symptomless, a few can produce retinal lesions and, in immunocompromised persons or when congenitally contracted, can progress to life-threatening central nervous system disseminated infections. Therefore, quick, and precise diagnosis is a must. Molecular techniques nowadays play a crucial role in toxoplasmosis diagnosis, particularly in immunocompromised patients or congenital toxoplasmosis. This review aimed to detail recent advancements in molecular diagnostics of T. gondii infections. The terms "Toxoplasmosis," "Molecular diagnostics," "PCR," "qPCR," "B1," and "rep529" were used to search the English-language literature. In developed nations, conventional PCR (PCR) and nested PCR have been supplanted by quantitative PCR (qPCR), although they are still widely employed in poor nations. The diagnosis of toxoplasmosis has been revolutionized by the emergence of molecular diagnostics. Unfortunately, there is still substantial interlaboratory variability. There is an immediate need for standardization to increase the comparability of results between laboratories and clinical trials. Graphical abstract A graphical abstract highlighting the summary of Toxoplasma molecular diagnostics, created using Biorender.com.
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Affiliation(s)
- Eman Fathi Fadel
- Department of Medical Parasitology, Faculty of Medicine, Sohag University, Sohag, Egypt
| | - Hanaa Ahmed EL-Hady
- Department of Medical Parasitology, Faculty of Medicine, Sohag University, Sohag, Egypt
| | - Amal Mostafa Ahmed
- Department of Medical Parasitology, Faculty of Medicine, Sohag University, Sohag, Egypt
| | - Mohammed Essa Marghany Tolba
- Department of Microbiology and Clinical Parasitology, Faculty of Medicine, King Khaled University, Abha, Saudi Arabia
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Seroprevalence and Genetic Characterization of Toxoplasma gondii among Children with Neurodevelopmental Disorders in Egypt. J Trop Med 2022; 2022:2343679. [PMID: 35669051 PMCID: PMC9166983 DOI: 10.1155/2022/2343679] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 05/09/2022] [Accepted: 05/12/2022] [Indexed: 11/25/2022] Open
Abstract
Toxoplasma gondii is a parasite with a special predilection for the central nervous system. Toxoplasmosis's contribution to the triggering of many neurodevelopmental disorders was established. This study aimed to detect the seroprevalence and genotypes of T. gondii strains in children with neurodevelopmental disorders. The study included 180 children with neurodevelopmental disorders and 180 children in the control group. Assessment of seropositivity of Toxoplasma IgM and IgG antibodies in patients and controls was carried out. Genetic characterization of T. gondii was obtained by nested polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) technique targeting dense granule gene (GRA6). Our results showed that the overall seroprevalence of T. gondii antibodies in the patient and controls was 35.6% and 11.7%, respectively. Nested PCR showed positivity in 11.1% of the patient group for T. gondii DNA. T. gondii seropositivity rate was significantly high in patients with hydrocephalus and also in patients with epilepsy. Positive nested PCR was significantly high in children with hydrocephalus only. Genotyping using nested PCR-RFLP showed genotype I (80%) followed by atypical strains (20%) with no association with any specific clinical presentation. In conclusion, among toxoplasmosis-positive children with neurodevelopmental disorders, analysis of T. gondii GRA6 locus revealed the predominance of type I genotype followed by atypical strains.
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Smith JR, Ashander LM, Arruda SL, Cordeiro CA, Lie S, Rochet E, Belfort R, Furtado JM. Pathogenesis of ocular toxoplasmosis. Prog Retin Eye Res 2020; 81:100882. [PMID: 32717377 DOI: 10.1016/j.preteyeres.2020.100882] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/26/2020] [Accepted: 06/30/2020] [Indexed: 12/12/2022]
Abstract
Ocular toxoplasmosis is a retinitis -almost always accompanied by vitritis and choroiditis- caused by intraocular infection with Toxoplasma gondii. Depending on retinal location, this condition may cause substantial vision impairment. T. gondii is an obligate intracellular protozoan parasite, with both sexual and asexual life cycles, and infection is typically contracted orally by consuming encysted bradyzoites in undercooked meat, or oocysts on unwashed garden produce or in contaminated water. Presently available anti-parasitic drugs cannot eliminate T. gondii from the body. In vitro studies using T. gondii tachyzoites, and human retinal cells and tissue have provided important insights into the pathogenesis of ocular toxoplasmosis. T. gondii may cross the vascular endothelium to access human retina by at least three routes: in leukocyte taxis; as a transmigrating tachyzoite; and after infecting endothelial cells. The parasite is capable of navigating the human neuroretina, gaining access to a range of cell populations. Retinal Müller glial cells are preferred initial host cells. T. gondii infection of the retinal pigment epithelial cells alters the secretion of growth factors and induces proliferation of adjacent uninfected epithelial cells. This increases susceptibility of the cells to parasite infection, and may be the basis of the characteristic hyperpigmented toxoplasmic retinal lesion. Infected epithelial cells also generate a vigorous immunologic response, and influence the activity of leukocytes that infiltrate the retina. A range of T. gondii genotypes are associated with human ocular toxoplasmosis, and individual immunogenetics -including polymorphisms in genes encoding innate immune receptors, human leukocyte antigens and cytokines- impacts the clinical manifestations. Research into basic pathogenic mechanisms of ocular toxoplasmosis highlights the importance of prevention and suggests new biological drug targets for established disease.
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Affiliation(s)
- Justine R Smith
- Eye & Vision Health and Flinders Centre for Innovation in Cancer, Flinders University College of Medicine & Public Health, Adelaide, Australia; Formerly of Casey Eye Institute, Oregon Health & Science University, USA.
| | - Liam M Ashander
- Eye & Vision Health and Flinders Centre for Innovation in Cancer, Flinders University College of Medicine & Public Health, Adelaide, Australia; Formerly of Casey Eye Institute, Oregon Health & Science University, USA
| | - Sigrid L Arruda
- Department of Ophthalmology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Cynthia A Cordeiro
- Cordeiro et Costa Ophtalmologie, Campos dos Goytacazes, Brazil; Formerly of Department of Ophthalmology, Federal University of Minas Gerais School of Medicine, Belo Horizonte, Brazil
| | - Shervi Lie
- Eye & Vision Health and Flinders Centre for Innovation in Cancer, Flinders University College of Medicine & Public Health, Adelaide, Australia
| | - Elise Rochet
- Eye & Vision Health and Flinders Centre for Innovation in Cancer, Flinders University College of Medicine & Public Health, Adelaide, Australia
| | - Rubens Belfort
- Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil
| | - João M Furtado
- Department of Ophthalmology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil; Formerly of Casey Eye Institute, Oregon Health & Science University, USA
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Vilares A, Borges V, Sampaio D, Ferreira I, Martins S, Vieira L, Gargaté MJ, Gomes JP. Towards a rapid sequencing-based molecular surveillance and mosaicism investigation of Toxoplasma gondii. Parasitol Res 2020; 119:587-599. [PMID: 31897784 DOI: 10.1007/s00436-019-06523-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 10/23/2019] [Indexed: 11/30/2022]
Abstract
Advances in molecular epidemiology of Toxoplasma gondii are hampered by technical and cost-associated hurdles underlying the acquisition of genomic data from parasites. In order to implement an enhanced genotyping approach for molecular surveillance of T. gondii, we applied a multi-locus amplicon-based sequencing strategy to samples associated with human infection. This approach, targeting genome-dispersed polymorphic loci potentially involved in adaptation and virulence, genetically discriminated almost all 68 studied strains and revealed a scenario of marked genomic mosaicism. Two-thirds (n = 43) of all strains were classified as recombinant, although recombination seemed to be linked to the classical archetypal lineage. While 92% of the Sag2 archetype I strains revealed genetic mosaicism, only 45% of Sag2 archetype II strains were identified as recombinant. Contrarily to the virulence-associated archetype I, most type II strains (regardless of their recombination background) were non-virulent in mouse. Besides Sag2, some of the newly studied loci (namely the type I/I-like alleles of Sag1, B17, PK1, and Sag3 and type III/III-like alleles of TgM-A) constitute promising candidates to rapidly infer T. gondii mouse virulence. Our successful attempt to capture microsatellite length variation launches good perspectives for the straightforward transition from the laborious intensive historical method to more informative next-generation sequencing (NGS)/bioinformatics-based methodologies. Overall, while T. gondii whole-genome sequencing will be hardly feasible in most laboratories, this study shows that a discrete loci panel has the potential to improve the molecular epidemiology of T. gondii towards a better monitoring of circulating genotypes with clinical importance.
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Affiliation(s)
- Anabela Vilares
- National Reference Laboratory of Parasitic and Fungal Infections, Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016, Lisbon, Portugal. .,Faculty of Sciences, BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Lisboa, Portugal.
| | - Vítor Borges
- Bioinformatics Unit, Infectious Diseases Department, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016, Lisbon, Portugal
| | - Daniel Sampaio
- Innovation and Technology Unit, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016, Lisbon, Portugal
| | - Idalina Ferreira
- National Reference Laboratory of Parasitic and Fungal Infections, Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016, Lisbon, Portugal
| | - Susana Martins
- National Reference Laboratory of Parasitic and Fungal Infections, Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016, Lisbon, Portugal
| | - Luis Vieira
- Innovation and Technology Unit, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016, Lisbon, Portugal.,Centre for Toxicogenomics and Human Health (ToxOmics), Genetics, Oncology and Human Toxicology, Nova Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Maria João Gargaté
- National Reference Laboratory of Parasitic and Fungal Infections, Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016, Lisbon, Portugal
| | - João Paulo Gomes
- Bioinformatics Unit, Infectious Diseases Department, National Institute of Health Dr. Ricardo Jorge, Av. Padre Cruz, 1649-016, Lisbon, Portugal
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Abd El-Razik KA, Barakat AMA, Hussein HA, Younes AM, Elfadaly HA, Eldebaky HA, Soliman YA. Seroprevalence, isolation, molecular detection and genetic diversity of Toxoplasma gondii from small ruminants in Egypt. J Parasit Dis 2018; 42:527-536. [PMID: 30538350 PMCID: PMC6261144 DOI: 10.1007/s12639-018-1029-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Accepted: 09/07/2018] [Indexed: 10/28/2022] Open
Abstract
Toxoplasmosis is an infectious zoonotic disease caused by protozoan Toxoplasma gondii. Detection of T. gondii infection with touchy and particular strategies is a key advance to control and prevent toxoplasmosis. Genotyping can explain the virulence, epidemiology and setting up new methodologies for diagnosis and control in human and animals. The point of this study was to assess the seroprevalence of T. gondii in sheep and goat in Egypt and to comprehend the genetic variety of T. gondii isolates circling in Egypt. Blood samples were gathered from 113 ewes and 95 she-goats from three Egyptian governorates (Cairo, Giza and Al-Sharkia). Also blood and tissue samples were gathered from 193 sheep and 51 goats from Cairo and Giza abattoirs. All samples were assayed serologically utilizing ELISA and OnSite Toxo IgG/IgM Rapid test cassettes (OTRT) tests and the tissue samples of the seropositive animals were digested and microscopically examined then bio-assayed in mice as viability test. All the T. gondii isolates undergo molecular identification using PCR and genotyped utilizing nPCR/RFLP analysis of SAG2 gene. The total seropositivity of live sheep and goat was 47.15 and 39.2% utilizing ELISA and OTRT respectively. Concerning abattoirs, seropositivity, positive microscopic examination, mice viability from sheep samples were 47.1%, 37.3% and 44.1% respectively while that of goats were 45.5%, 33.3% and 48.6% respectively. Eighteen T. gondii isolates were affirmed utilizing PCR. Genotyping confirmed 10 isolates (55.5%) as type II, 6 (33.3%) as type III and 2 (11.1%) as atypical genotypes. Type II and III are the genotypes mostly circling among small ruminants in Egypt and this is most significance for the public health in Egypt.
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Affiliation(s)
| | | | - Hany A. Hussein
- Department of Animal Reproduction, National Research Centre, Dokki, Giza, Egypt
| | | | - Hassan A. Elfadaly
- Department of Zoonotic Diseases, National Research Centre, Dokki, Giza, Egypt
| | - Hazem A. Eldebaky
- Department of Animal Reproduction, National Research Centre, Dokki, Giza, Egypt
| | - Yousef A. Soliman
- Central Lab for Evaluation of Vet. Biologics (CLEVB), Abbasia, Cairo, Egypt
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