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Laguardia MC, Carellos EVM, Andrade GMQ, Carneiro M, Januário JN, Vitor RWDA. Evaluation of different cut-off points for IgG avidity and IgM in the diagnosis of acute toxoplasmosis in pregnant women participating in a congenital toxoplasmosis screening program. Rev Inst Med Trop Sao Paulo 2024; 66:e43. [PMID: 39082482 PMCID: PMC11295287 DOI: 10.1590/s1678-9946202466043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Accepted: 06/10/2024] [Indexed: 08/04/2024] Open
Abstract
The main social impact of toxoplasmosis stems from its ability to be vertically transmitted. Postnatally acquired infection is generally asymptomatic in approximately 70-90% of cases, making diagnosis often dependent on laboratory tests using serological methods to search for anti-T. gondii antibodies. This study aimed to investigate the ability of the VIDAS TOXO IgG avidity and VIDAS TOXO IgM assays to confirm recent toxoplasmosis. In total, 341 pregnant women with suspected acute toxoplasmosis were systematically monitored in the Program for Control of Congenital Toxoplasmosis in Minas Gerais State, Brazil. We conducted an observational analytical-descriptive cross-sectional study and grouped according to clinical and laboratory criteria as having acute or chronic toxoplasmosis. The VIDAS TOXO IgG avidity and VIDAS TOXO IgM assays were evaluated to investigate the capacity to identify acute infection. IgG avidity showed good performance in identifying acute toxoplasmosis when the IgG avidity index was lower than or equal to 0.1. Values greater than or equal to 3.16 according to the TOXO IgM kit were associated with a greater chance of acute infection. These results may contribute to a more adequate diagnosis of acute gestational toxoplasmosis and, consequently, the avoidance of inadequate or unnecessary treatments.
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Affiliation(s)
- Michelle Costa Laguardia
- Secretaria de Estado de Saúde de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Departamento de Parasitologia, Belo Horizonte, Minas Gerais, Brazil
| | - Ericka Viana Machado Carellos
- Universidade Federal de Minas Gerais, Faculdade de Medicina, Departamento de Pediatria, Belo Horizonte, Minas Gerais, Brazil
| | - Glaucia Manzan Queiroz Andrade
- Universidade Federal de Minas Gerais, Faculdade de Medicina, Departamento de Pediatria, Belo Horizonte, Minas Gerais, Brazil
| | - Mariângela Carneiro
- Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Departamento de Parasitologia, Belo Horizonte, Minas Gerais, Brazil
| | - José Nélio Januário
- Universidade Federal de Minas Gerais, Faculdade de Medicina, Núcleo de Ações e Pesquisa em Apoio Diagnóstico, Belo Horizonte, Minas Gerais, Brazil
| | - Ricardo Wagner de Almeida Vitor
- Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Departamento de Parasitologia, Belo Horizonte, Minas Gerais, Brazil
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Ikuta K, Kanno R, Bessho T, Koshizuka T, Suzutani T. Evaluation of Toxoplasma gondii IgG avidity assays through a comparison of IgM serostatus. Diagn Microbiol Infect Dis 2023; 105:115901. [PMID: 36889215 DOI: 10.1016/j.diagmicrobio.2023.115901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 12/23/2022] [Accepted: 01/13/2023] [Indexed: 01/20/2023]
Abstract
Primary Toxoplasma gondii (T. gondii) infection during pregnancy could result in congenital disease with severe clinical complications. IgM antibodies are one of the indices of primary infection. The IgG avidity index (AI) is also known to remain low for at least 3 months after primary infection. Here, we evaluated and compared the performance of T. gondii IgG avidity assays as confirmed by T. gondii IgM serostatus and number of days post-exposure. Four assays preferentially used in Japan were employed to measure the T. gondii IgG AI. Results for the T. gondii IgG AI showed good concordance, particularly in cases with a low IgG AI. This study confirms that the combination of T. gondii IgM and IgG AI tests is a reliable and suitable method for identifying T. gondii primary infections. Our study proposes the necessity of measuring the T. gondii IgG AI as an additional indicator of T. gondii primary infection.
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Affiliation(s)
- Kazufumi Ikuta
- Department of Microbiology, Fukushima Medical University School of Medicine, Fukushima , Japan; Division of Microbiology, Tohoku Medical and Pharmaceutical University School of Medicine, Miyagi, Japan
| | - Ryoko Kanno
- Department of Microbiology, Fukushima Medical University School of Medicine, Fukushima , Japan
| | - Tomoaki Bessho
- Department of Vaccine and Diagnostics, Life Innovation Center, Denka Co., Ltd, Niigata, Japan
| | - Tetsuo Koshizuka
- Department of Microbiology, Fukushima Medical University School of Medicine, Fukushima , Japan; Laboratory of Microbiology and Immunology, Gifu Pharmaceutical University, Gifu, Japan
| | - Tatsuo Suzutani
- Department of Microbiology, Fukushima Medical University School of Medicine, Fukushima , Japan.
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Kodym P, Kurzová Z, Berenová D, Malý M. Detection of persistent low IgG avidity-an interpretative problem in the diagnosis of acute toxoplasmosis. PLoS One 2023; 18:e0284499. [PMID: 37053239 PMCID: PMC10101438 DOI: 10.1371/journal.pone.0284499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 04/02/2023] [Indexed: 04/14/2023] Open
Abstract
OBJECTIVES For the proper diagnosis of toxoplasmosis it is essential to determine the stage of the infection, for which the most preferred method is IgG avidity test. The avidity index (AI) should initially be low (AI≤0.3) in the acute phase and increase during the infection. However, persistent low avidity can occur in patients with latent toxoplasmosis, which can complicate the interpretation of the results. The aim of the study is to explain the causes of this phenomenon. METHODOLOGY A retrospective study was carried out with 717 serum samples collected from 442 patients from the categories of pregnant and non-pregnant women, men, and newborns + infants (age < 0.5 year). The trends of AI kinetics were evaluated in repeatedly examined patients. The frequency of cases with low avidity was compared in individual categories of patients and in groups of people with acute and non-acute toxoplasmosis. RESULTS The proportion of patients with initially low avidity was 42.1% in the acute toxoplasmosis group while it was 13.0% in the non-acute groups. In uninfected newborns with anti-Toxoplasma antibodies transmitted from the mother, a decrease in IgG avidity levels over time was observed, resulting in 29.2% of samples showing low (improper) avidity. While the dynamics of IgG avidity and the frequency of cases of improperly low avidity were similar in men and pregnant and non-pregnant women, the category of newborns and infants differed substantially for these indicators. CONCLUSIONS Due to acceptable specificity and negative predictive value, high avidity can rule out acute toxoplasmosis, but moderate sensitivity complicates the possibility of its confirmation. The results of the avidity test must be interpreted in the context of the results of other methods.
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Affiliation(s)
- Petr Kodym
- National Reference Laboratory for Toxoplasmosis, National Institute of Public Health, Prague, Czech Republic
| | - Zuzana Kurzová
- National Reference Laboratory for Toxoplasmosis, National Institute of Public Health, Prague, Czech Republic
| | - Dagmar Berenová
- National Reference Laboratory for Toxoplasmosis, National Institute of Public Health, Prague, Czech Republic
| | - Marek Malý
- National Institute of Public Health, Unit of Biostatistics, Prague, Czech Republic
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Khalil A, Sotiriadis A, Chaoui R, da Silva Costa F, D'Antonio F, Heath PT, Jones C, Malinger G, Odibo A, Prefumo F, Salomon LJ, Wood S, Ville Y. ISUOG Practice Guidelines: role of ultrasound in congenital infection. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2020; 56:128-151. [PMID: 32400006 DOI: 10.1002/uog.21991] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 01/27/2020] [Indexed: 06/11/2023]
Affiliation(s)
- A Khalil
- Fetal Medicine Unit, St George's University Hospitals NHS Foundation Trust, University of London, London, UK
- Vascular Biology Research Centre, Molecular and Clinical Sciences Research Institute, St George's University of London, London, UK
| | - A Sotiriadis
- Second Department of Obstetrics and Gynecology, Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - R Chaoui
- Center for Prenatal Diagnosis and Human Genetics, Berlin, Germany
| | - F da Silva Costa
- Department of Gynecology and Obstetrics, Ribeirao Preto Medical School, University of São Paulo, Ribeirao Preto, São Paulo, Brazil
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, Australia
| | - F D'Antonio
- Women's Health and Perinatology Research Group, Department of Clinical Medicine, Faculty of Health Sciences, UiT - The Arctic University of Norway, Tromsø, Norway
- Department of Obstetrics and Gynecology, University Hospital of Northern Norway, Tromsø, Norway
| | - P T Heath
- Paediatric Infectious Diseases Research Group and Vaccine Institute, St George's University of London and St George's University Hospitals NHS Trust, London, UK
| | - C Jones
- Faculty of Medicine and Institute for Life Sciences, University of Southampton and University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - G Malinger
- Ultrasound Unit, Lis Maternity Hospital, Tel Aviv Sourasky Medical Center, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - A Odibo
- Department of Obstetrics and Gynecology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - F Prefumo
- Division of Obstetrics and Gynecology, Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
| | - L J Salomon
- Department of Obstetrics and Fetal Medicine, Hopital Necker-Enfants Malades, Assistance Publique-Hopitaux de Paris, Paris Descartes University, Paris, France
| | | | - Y Ville
- Department of Obstetrics and Fetal Medicine, Hopital Necker-Enfants Malades, Assistance Publique-Hopitaux de Paris, Paris Descartes University, Paris, France
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Garnaud C, Fricker-Hidalgo H, Evengård B, Álvarez-Martínez MJ, Petersen E, Kortbeek LM, Robert-Gangneux F, Villena I, Costache C, Paul M, Meroni V, Guy E, Chiodini PL, Brenier-Pinchart MP, Pelloux H. Toxoplasma gondii-specific IgG avidity testing in pregnant women. Clin Microbiol Infect 2020; 26:1155-1160. [PMID: 32334096 DOI: 10.1016/j.cmi.2020.04.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 04/07/2020] [Accepted: 04/14/2020] [Indexed: 11/30/2022]
Abstract
BACKGROUND The parasite Toxoplasma gondii can cause congenital toxoplasmosis following primary infection in a pregnant woman. It is therefore important to distinguish between recent and past infection when both T. gondii-specific IgM and IgG are detected in a single serum in pregnant women. Toxoplasma gondii-specific IgG avidity testing is an essential tool to help to date the infection. However, interpretation of its results can be complex. OBJECTIVES To review the benefits and limitations of T. gondii-specific avidity testing in pregnant women, to help practitioners to interpret the results and adapt the patient management. SOURCES PubMed search with the keywords avidity, toxoplasmosis and Toxoplasma gondii for articles published from 1989 to 2019. CONTENT Toxoplasma gondii-specific IgG avidity testing remains a key tool for dating a T. gondii infection in immunocompetent pregnant women. Several commercial assays are available and display comparable performances. A high avidity result obtained on a first-trimester serum sample is indicative of a past infection, which occurred before pregnancy. To date, a low avidity result must still be considered as non-informative to date the infection, although some authors suggest that very low avidity results are highly suggestive of recent infections depending on the assay. Interpretation of low or grey zone avidity results on a first-trimester serum sample, as well as any avidity result on a second-trimester or third-trimester serum sample, is more complex and requires recourse to expert toxoplasmosis laboratories. IMPLICATIONS Although used for about 30 years, T. gondii-specific avidity testing has scarcely evolved. The same difficulties in interpretation have persisted over the years. Some authors have proposed additional thresholds to exclude an infection of <9 months, or in contrast to confirm a recent infection. Such thresholds would be of great interest to adapt management of pregnant women and avoid unnecessary treatment; however, they need confirmation and further studies.
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Affiliation(s)
- C Garnaud
- Université Grenoble Alpes, CNRS, Grenoble INP, TIMC-IMAG, Grenoble, France; Parasitology-Mycology, CHU Grenoble Alpes, Grenoble, France.
| | | | - B Evengård
- Department Clinical Microbiology, Umea University, Umea, Sweden
| | - M J Álvarez-Martínez
- Microbiology Department, Hospital Clínic-ISGLOBAL, University of Barcelona, Barcelona, Spain
| | - E Petersen
- Directorate General for Disease Surveillance and Control, Ministry of Health, Oman; Institute for Clinical Medicine, Faculty of Health Science, University of Aarhus, Denmark; ESCMID Emerging Infections Task Force, ESCMID, Basel, Switzerland
| | - L M Kortbeek
- National Institute for Public Health and the Environment; Centre for Infectious Disease Control (CIb) Bilthoven, the Netherlands
| | - F Robert-Gangneux
- Université Rennes, CHU Rennes, Inserm, EHESP, Irset (Institut de Recherche en Santé Environnement et Travail)-UMR_S 1085, Rennes, France
| | - I Villena
- Université Reims Champagne-Ardenne EA 7510, CHU Reims, Centre National de Référence de La Toxoplasmose, CRB Toxoplasma, Reims, France
| | - C Costache
- Microbiology Department 'Iuliu Hatieganu', University of Medicine and Pharmacy Cluj-Napoca, Romania
| | - M Paul
- Department and Clinic of Tropical and Parasitic Diseases, University of Medical Sciences, Poznan, Poland
| | - V Meroni
- University Pavia Internal Medicine and Medical Therapy Department, Microbiology and Virology Department IRCCS, Foundation San Matteo Polyclinic, Pavia Italy
| | - E Guy
- Toxoplasma Reference Unit, Public Health Wales Microbiology, Swansea, UK
| | - P L Chiodini
- Hospital for Tropical Diseases and the London School of Hygiene and Tropical Medicine, London, UK
| | - M-P Brenier-Pinchart
- Parasitology-Mycology, CHU Grenoble Alpes, Grenoble, France; Université Grenoble Alpes, INSERM-CNRS, Institute for Advanced Biosciences, Grenoble, France
| | - H Pelloux
- Parasitology-Mycology, CHU Grenoble Alpes, Grenoble, France; Université Grenoble Alpes, INSERM-CNRS, Institute for Advanced Biosciences, Grenoble, France
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Barros GB, Lemos EM, e Silva-dos-Santos PP, Dietze R, Zandonade E, Mineo JR, de Oliveira Silva DA, Pajuaba ACM, de Souza Gomes M, do Amaral LR, Coelho-dos-Reis JG, Martins-Filho OA, Serufo JC. Proposed panel of diagnostic tools for accurate temporal classification of symptomatic T. gondii infection. J Immunol Methods 2017; 451:61-70. [DOI: 10.1016/j.jim.2017.08.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 08/08/2017] [Accepted: 08/08/2017] [Indexed: 11/29/2022]
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Evaluation of serological and molecular tests used to identify Toxoplasma gondii infection in pregnant women attended in a public health service in São Paulo state, Brazil. Diagn Microbiol Infect Dis 2017; 89:13-19. [PMID: 28689893 DOI: 10.1016/j.diagmicrobio.2017.06.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 06/07/2017] [Accepted: 06/09/2017] [Indexed: 11/23/2022]
Abstract
Toxoplasmosis during pregnancy can have severe consequences. The use of sensitive and specific serological and molecular methods is extremely important for the correct diagnosis of the disease. We compared the ELISA and ELFA serological methods, conventional PCR (cPCR), Nested PCR and quantitative PCR (qPCR) in the diagnosis of Toxoplasma gondii infection in pregnant women without clinical suspicion of toxoplasmosis (G1=94) and with clinical suspicion of toxoplasmosis (G2=53). The results were compared using the Kappa index, and the sensitivity, specificity, positive predictive value and negative predictive value were calculated. The results of the serological methods showed concordance between the ELISA and ELFA methods even though ELFA identified more positive cases than ELISA. Molecular methods were discrepant with cPCR using B22/23 primers having greater sensitivity and lower specificity compared to the other molecular methods.
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Help in the Choice of Automated or Semiautomated Immunoassays for Serological Diagnosis of Toxoplasmosis: Evaluation of Nine Immunoassays by the French National Reference Center for Toxoplasmosis. J Clin Microbiol 2016; 54:3034-3042. [PMID: 27733631 DOI: 10.1128/jcm.01193-16] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 09/28/2016] [Indexed: 11/20/2022] Open
Abstract
Toxoplasmosis, a benign infection, is asymptomatic or paucisymptomatic in over 80% of cases, except in immunocompetent patients suffering from ocular toxoplasmosis or in immunocompromised patients with opportunistic or congenital toxoplasmosis. Diagnosis is based mainly on serology testing. Thus, we compared the performance of the nine most commonly used commercial automated or semiautomated immunoassays for IgG and IgM Toxoplasma gondii antibody detection, that is, the Advia Centaur, Architect, AxSYM, Elecsys, Enzygnost, Liaison, Platelia, VIDAS, and VIDIA assays. The assays were conducted on four panels of serum samples derived during routine testing from patients with an interfering disease and who exhibited a low IgG antibody level in one of two clinical settings, namely, acute or chronic toxoplasmosis. As a result, IgG sensitivities ranged from 97.1% to 100%, and IgG specificities ranged from 99.5% to 100%. For IgG quantification, strong differences in IgG titers (expressed in IU/ml) were noted depending on the assay used. IgM sensitivities ranged from 65% to 97.9%, and IgM specificities ranged from 92.6% to 100%. For defining the best serological strategies to be implemented, it appears crucial to compare the diagnostic performance of the different tests with respect to their specificity and sensitivity in detecting the presence of IgG and IgM antibodies.
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Persistent Low Toxoplasma IgG Avidity Is Common in Pregnancy: Experience from Antenatal Testing in Norway. PLoS One 2015; 10:e0145519. [PMID: 26714282 PMCID: PMC4703128 DOI: 10.1371/journal.pone.0145519] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 12/05/2015] [Indexed: 11/19/2022] Open
Abstract
The parasite Toxoplasma gondii might harm the fetus if a woman is infected during pregnancy. IgG seroconversion and significant increase in IgG antibody amount in pregnancy indicates maternal infection. Presence of toxoplasma immunoglobulin M (IgM), immunoglobulin G (IgG) and low IgG avidity in a single serum sample indicates possible maternal infection, but positive toxoplasma IgM and low IgG avidity may persist for months and even years. We aimed to evaluate avidity development during pregnancy in a retrospective study. Serial blood samples from 176 pregnant women admitted to Oslo University Hospital 1993–2013 for amniocentesis because of suspected toxoplasma infection were included. Data were obtained from journals and laboratory records. The avidity method used was based on Platelia Toxo IgG assay. Mean maternal age at first serology was 29.9 years (SD 5.2, range 18–42). In 37 (21%) women only the avidity increased from low to high in < 3 months. In 139 (79%) the IgG avidity remained below the high threshold ≥ 3 months and within this group 74 (42%) women had stable low IgG avidity during the observation period. Median gestational age at first test was 10.6 weeks (range 4.6–28.7). Fetal infection was detected in four children, but none among children whose mother had stable low IgG avidity. The first antenatal toxoplasma serology should ideally be collected in early pregnancy and if stable values of toxoplasma IgM and low IgG-avidity are detected in a second sample after three to four weeks, the need for amniocentesis can be questioned.
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Liu Q, Wang ZD, Huang SY, Zhu XQ. Diagnosis of toxoplasmosis and typing of Toxoplasma gondii. Parasit Vectors 2015; 8:292. [PMID: 26017718 PMCID: PMC4451882 DOI: 10.1186/s13071-015-0902-6] [Citation(s) in RCA: 243] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 05/18/2015] [Indexed: 11/25/2022] Open
Abstract
Toxoplasmosis, caused by the obligate intracellular protozoan Toxoplasma gondii, is an important zoonosis with medical and veterinary importance worldwide. The disease is mainly contracted by ingesting undercooked or raw meat containing viable tissue cysts, or by ingesting food or water contaminated with oocysts. The diagnosis and genetic characterization of T. gondii infection is crucial for the surveillance, prevention and control of toxoplasmosis. Traditional approaches for the diagnosis of toxoplasmosis include etiological, immunological and imaging techniques. Diagnosis of toxoplasmosis has been improved by the emergence of molecular technologies to amplify parasite nucleic acids. Among these, polymerase chain reaction (PCR)-based molecular techniques have been useful for the genetic characterization of T. gondii. Serotyping methods based on polymorphic polypeptides have the potential to become the choice for typing T. gondii in humans and animals. In this review, we summarize conventional non-DNA-based diagnostic methods, and the DNA-based molecular techniques for the diagnosis and genetic characterization of T. gondii. These techniques have provided foundations for further development of more effective and accurate detection of T. gondii infection. These advances will contribute to an improved understanding of the epidemiology, prevention and control of toxoplasmosis.
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Affiliation(s)
- Quan Liu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China. .,Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Institute, Academy of Military Medical Sciences, Changchun, Jilin Province, 130122, People's Republic of China.
| | - Ze-Dong Wang
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Institute, Academy of Military Medical Sciences, Changchun, Jilin Province, 130122, People's Republic of China.
| | - Si-Yang Huang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China. .,Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University College of Veterinary Medicine, Yangzhou, Jiangsu Province, 225009, People's Republic of China.
| | - Xing-Quan Zhu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China. .,Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University College of Veterinary Medicine, Yangzhou, Jiangsu Province, 225009, People's Republic of China.
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Abstract
Methods for the diagnosis of parasitic infections have stagnated in the past three decades. Labor-intensive methods such as microscopy still remain the mainstay of several diagnostic laboratories. There is a need for more rapid tests that do not sacrifice sensitivity and that can be used in both clinical settings as well as in poor resource field settings. The fields of diagnostic medical parasitology, treatment, and vaccines are undergoing dramatic change. In recent years, there has been tremendous effort to focus research on the development of newer diagnostic methods focusing on serological, molecular, and proteomic approaches. This article examines the various diagnostic tools that are being used in clinical laboratories, optimized in reference laboratories, and employed in mass screening programs.
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Affiliation(s)
| | - Momar Ndao
- Department of Microbiology & Immunology, McGill University, Montreal, Canada
- National Reference Centre for Parasitology, Research Institute of the McGill University Health Center, Montreal, Canada
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Deshpande PS, Kotresha D, Noordin R, Yunus MH, Saadatnia G, Golkar M, Osman S, Karim IZA, Ghaffarifar F. IgG avidity Western blot using Toxoplasma gondii rGRA-7 cloned from nucleotides 39-711 for serodiagnosis of acute toxoplasmosis. Rev Inst Med Trop Sao Paulo 2013; 55:79-83. [PMID: 23563759 DOI: 10.1590/s0036-46652013000200003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 08/13/2012] [Indexed: 11/21/2022] Open
Abstract
Toxoplasmosis is an important cause of congenital infection. The present study was performed to evaluate the usefulness of recombinant (r) GRA-7 cloned from nucleotides (n) 39-711 in discriminating between acute and chronic toxoplasmosis. First, commercial IgM, IgG and IgG avidity ELISAs were used to determine the serological profile of the sera. Serum samples were from 20 symptomatic patients with acute infection (low IgG avidity, IgM positive), 10 with chronic infection (high IgG avidity, IgM negative) and 10 with indeterminate IgG avidity (IgM positive) which were tested for IgG avidity status with an in-house developed IgG avidity Western blot using the rGRA-7 recombinant antigen. All 20 sera from cases of probable acute infection showed bands which either faded out completely or reduced significantly in intensity after treatment with 8 M urea, whereas the band intensities of the 10 serum samples from chronic cases remained the same. Of the 10 sera with indeterminate IgG avidity status, after treatment with 8 M urea the band intensities with six sera remained the same, two sera had completely faded bands and another two sera had significantly reduced band intensities. Discrimination between acute and chronic toxoplasmosis was successfully performed by the in-house IgG avidity Western blot.
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Affiliation(s)
- Poonam S Deshpande
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800 Penang, Malaysia
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Sadraie J, Bahadory ES, Marsusi V. The merits of designed ELISA avidity kit in detection of Toxoplasma gondii IgG antibody in laboratory conditions. Trop Parasitol 2013; 3:40-3. [PMID: 23961440 PMCID: PMC3745670 DOI: 10.4103/2229-5070.113904] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 06/24/2013] [Indexed: 11/04/2022] Open
Abstract
Background: Toxoplasmosis is a parasitic disease which may cause some laboratory symptoms in infected individuals. One of the main ways to transmit this organism is placenta to the fetus pathway. If this transmission occurs in the 3rd month of pregnancy, the abortion, central nerve system and ocular disorder will happen. Because of this issue, the precise technique for the detection of Toxoplasma antibodies such as immunoglobulin G (IgG) and immunoglobulin M IgM are important, as they contain ELISA and ELISA avidity. Materials and Methods: In this survey, the main samples are serum and amniotic fluid that were collected from 48 pregnant women infected with Toxoplasma gondii in Shariaty hospital. This survey is attempted to design ELISA avidity kit in Tarbiat Modates University. Results: The results from this survey show that, in these total pregnant women the infection by T. gondii has occurred and many of them are infected currently. Conclusions: In the simple ELISA technique, the only antibody that can be detected precisely is IgM; however, using this technique the IgG antibody can also be detected. In this new technique or ELISA avidity, in addition to detection of IgG antibody against T. gondii, the month of transmission of Toxoplasma is also interpreted.
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Affiliation(s)
- Javid Sadraie
- Department of Medical Parasitology, Faculty of Medical Sciences, Tarbiat Modaress University, Tehran, Iran
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Shepherd SJ, Kean J, Hutchinson SJ, Cameron SO, Goldberg DJ, Carman WF, Gunson RN, Aitken C. A hepatitis C avidity test for determining recent and past infections in both plasma and dried blood spots. J Clin Virol 2013; 57:29-35. [PMID: 23369886 DOI: 10.1016/j.jcv.2013.01.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 11/26/2012] [Accepted: 01/03/2013] [Indexed: 12/17/2022]
Abstract
BACKGROUND DBS testing has been used successfully to detect HCV antibody positive individuals. Determining how long someone has been infected is important for surveillance initiatives. Antibody avidity is a method that can be used to calculate recency of infection. OBJECTIVES A HCV avidity assay was evaluated for both plasma and DBS. STUDY DESIGN To measure antibody avidity a commercial HCV ELISA was modified using 7 M urea. The plasma samples were split into: group 1 (recently infected N = 19), group 2 (chronic carrier N = 300) and group 3 (resolved infection N = 82). Mock DBS made from group 1 (N = 12), group 2 (N = 50), group 3 (N = 25) and two seroconverter panels were evaluated. 133 DBS taken from patients known to have a resolved infection or be a chronic carrier were also tested. RESULTS The avidity assay cut-off was set at AI≤30 for a recent infection. Using sequential samples the assay could detect a recent infection in the first 4-5 months from the point of infection. Most of the false positive results (AI < 30 among cases known not to have had recent infection) were detected among known resolved infections, in both the plasma and DBS; as a result, a testing algorithm has been designed incorporating both PCR and two dilution factors. The sensitivity and specificity of the assay on plasma was 100% and 99.3%, respectively, while DBS had 100% sensitivity and 98.3% specificity. CONCLUSION The HCV avidity assay can be used to distinguish between chronic and recent infection using either plasma or DBS as the sample type.
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Affiliation(s)
- Samantha J Shepherd
- West of Scotland Specialist Virology Centre, Gartnavel General Hospital, 1053 Great Western Road, Glasgow, United Kingdom.
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Comparison of four commercially available avidity tests for Toxoplasma gondii-specific IgG antibodies. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2012; 20:197-204. [PMID: 23239801 DOI: 10.1128/cvi.00356-12] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Toxoplasma infection in pregnant women may cause congenital toxoplasmosis. Diagnosis of infection is based on serological tests aimed at detecting IgM and IgG antibodies against Toxoplasma gondii. However, IgM antibodies are not an accurate marker for discriminating between acute and latent infection. Detection of residual or persistent IgM may occur months or even years after primary infection, while the IgG avidity test is a rapid means of identifying latent infections in pregnant women who exhibit both IgG and IgM anti-Toxoplasma antibodies on initial testing during pregnancy. In this study, we assessed and compared the performances of four commercially available Toxoplasma IgG avidity tests in immunocompetent and immunocompromised patients with acute and latent toxoplasmosis. The positive predictive value of high avidity to confirm latent toxoplasmosis was 100% for all the assays, indicating that high avidity is a hallmark of latent infection. However, the negative predictive value of high avidity ranged from 99.2% (bioMérieux) to 95.3% (Abbott), indicating that acute toxoplasmosis could not be reliably diagnosed based on low IgG avidity alone. Thus, the avidity test provides a rapid means for identifying latent Toxoplasma infection in immunocompetent pregnant women presenting both IgG and IgM anti-Toxoplasma antibodies on initial testing. In terms of cost-effectiveness, avidity testing is a powerful tool that optimizes screening and follow-up of pregnant women while minimizing the costs of screening by avoiding subsequent costly maternal and fetal investigation and unnecessary treatment. The cheapest assay, Vidas Toxo IgG Avidity, also had the best performance for the diagnosis of latent toxoplasmosis.
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16
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Robert-Gangneux F, Dardé ML. Epidemiology of and diagnostic strategies for toxoplasmosis. Clin Microbiol Rev 2012; 25:264-96. [PMID: 22491772 PMCID: PMC3346298 DOI: 10.1128/cmr.05013-11] [Citation(s) in RCA: 999] [Impact Index Per Article: 83.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The apicomplexan parasite Toxoplasma gondii was discovered a little over 100 years ago, but knowledge of its biological life cycle and its medical importance has grown in the last 40 years. This obligate intracellular parasite was identified early as a pathogen responsible for congenital infection, but its clinical expression and the importance of reactivations of infections in immunocompromised patients were recognized later, in the era of organ transplantation and HIV infection. Recent knowledge of host cell-parasite interactions and of parasite virulence has brought new insights into the comprehension of the pathophysiology of infection. In this review, we focus on epidemiological and diagnostic aspects, putting them in perspective with current knowledge of parasite genotypes. In particular, we provide critical information on diagnostic methods according to the patient's background and discuss the implementation of screening tools for congenital toxoplasmosis according to health policies.
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Affiliation(s)
- Florence Robert-Gangneux
- Service de Parasitologie, Faculté de Médecine et Centre Hospitalier Universitaire de Rennes, Rennes, France.
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17
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Alvarado-Esquivel C, Niewiadomski A, Schweickert B, Liesenfeld O. Antiparasitic treatment suppresses production and avidity of Toxoplasma gondii-specific antibodies in a murine model of acute infection*. Eur J Microbiol Immunol (Bp) 2011; 1:249-55. [PMID: 24516731 DOI: 10.1556/eujmi.1.2011.3.9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 07/14/2011] [Indexed: 01/04/2023] Open
Abstract
Infection with Toxoplasma gondii during pregnancy may result in congenital transmission of the parasite. Infection is commonly diagnosed using serological tests for IgG, IgM and IgA antibodies. Avidity of IgG antibodies is used to exclude acute infection. Few studies have investigated the impact of antiparasitic treatment on the production of anti-T. gondii antibody and the avidity of IgG antibodies. We therefore investigated the production of IgG, IgM, and IgA antibodies and IgG avidity in a murine model of acute infection with 10 cysts of T. gondii. All antibody classes increased following infection. Treatment of mice with pyrimethamine/sulfadiazine but not with spiramycin or azithromycin at dosages equivalent to those used in patients resulted in a significant decrease in the concentration of T. gondii-specific IgG and IgM antibodies postinfection. IgG and IgM antibody decreases were paralleled by a significant reduction in cyst numbers in brains of mice treated with pyrimethamine/sulfadiazine but not with other drugs. In contrast, treatment with atovaquone did significantly reduce the concentrations of IgM antibodies and resulted in reduced IgG avidity indices. T. gondii-specific DNA was not detected in blood between days 1 and 3. In conclusion, antiparasitic treatment with pyrimethamine/sulfadiazine and atovaquone appears to impact the generation of antibody responses against T. gondii. Future studies will have to determine the specific impact of antiparasitic treatment on antibody responses and the consequences for the management of patients infected with T. gondii.
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Affiliation(s)
- C Alvarado-Esquivel
- Department of Microbiology and Hygiene, Charité Universitätsmedizin Berlin, Campus Benjamin Franklin Berlin Germany
| | - A Niewiadomski
- Department of Microbiology and Hygiene, Charité Universitätsmedizin Berlin, Campus Benjamin Franklin Berlin Germany
| | - B Schweickert
- Department of Microbiology and Hygiene, Charité Universitätsmedizin Berlin, Campus Benjamin Franklin Berlin Germany
| | - O Liesenfeld
- Department of Microbiology and Hygiene, Charité Universitätsmedizin Berlin, Campus Benjamin Franklin Berlin Germany
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Gay-Andrieu F, Fricker-Hidalgo H, Sickinger E, Espern A, Brenier-Pinchart MP, Braun HB, Pelloux H. Comparative evaluation of the ARCHITECT Toxo IgG, IgM, and IgG Avidity assays for anti-Toxoplasma antibodies detection in pregnant women sera. Diagn Microbiol Infect Dis 2009; 65:279-87. [DOI: 10.1016/j.diagmicrobio.2009.07.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Revised: 07/07/2009] [Accepted: 07/10/2009] [Indexed: 11/16/2022]
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Spiramycin treatment of Toxoplasma gondii infection in pregnant women impairs the production and the avidity maturation of T. gondii-specific immunoglobulin G antibodies. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2009; 16:1517-20. [PMID: 19692628 DOI: 10.1128/cvi.00253-09] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The aim of the study was to evaluate the influence of treatment with spiramycin on the increase of immunoglobulin G (IgG) titers and IgG avidity indexes (AI) in pregnant women with seroconversion from the beginning of therapy until delivery and after delivery. This group was compared with adult patients with recently acquired untreated toxoplasmosis. One hundred four samples from 32 pregnant women with seroconversion for toxoplasmosis and/or very low IgG AI were followed from the beginning of therapy with spiramycin until delivery. Twenty-nine women were further followed some months after delivery and interruption of therapy. Thirty-eight samples from 16 untreated, nonpregnant patients were evaluated as the control group. The Toxoplasma gondii-specific IgG antibody and the T. gondii-specific IgG AI were significantly delayed in pregnant women receiving therapy compared to nonpregnant, untreated controls, and the findings were consistent with the results of assays from two different manufacturers. The T. gondii-specific IgG AI increased in pregnant women after they gave birth. Avidity maturation is delayed during pregnancy and treatment, and low-avidity antibodies in pregnant women within 3 to 4 months cannot be taken as a sign of infection.
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