Evaluation of Toxoplasma gondii IgG avidity assays through a comparison of IgM serostatus

Ikuta, Kazufumi; Kanno, Ryoko; Bessho, Tomoaki; Koshizuka, Tetsuo; Suzutani, Tatsuo

doi:10.1016/j.diagmicrobio.2023.115901

Cited by 5 publications

(2 citation statements)

References 33 publications

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“…Thus, positive anti- T. gondii IgM must be interpreted with caution in the diagnosis of toxoplasmosis, as already described 26 . In a recent study, the combination of anti- T. gondii IgM and IgG avidity assays was shown to be a reliable and suitable method for diagnosing acute toxoplasmosis 27 .…”

Section: Discussionmentioning

confidence: 99%

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

Laguardia,

Carellos,

Andrade

et al. 2024

Rev. Inst. Med. trop. S. Paulo

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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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Section: Discussionmentioning

confidence: 99%

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

Laguardia,

Carellos,

Andrade

et al. 2024

Rev. Inst. Med. trop. S. Paulo

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“…The IgG Avidity ELISA test is used to differentiate between acute and chronic infections; however, it cannot be used at the beginning stages of an infection because the level of IgG antibodies must be su cient for the denaturing agents to take effect. The nal result is expressed as a percentage under the relative avidity index (RIA) [15,22,23].…”

Section: Immunodiagnostic Testsmentioning

confidence: 99%

In-house real-time PCR to detection Toxoplasma gondii in pregnant women candidates for amniocentesis and comparison with nested PCR and serologic methods in several clinical samples

Abedian,

Fakhar,

Kordi

et al. 2023

Preprint

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Background: Toxoplasmosis is a common parasitic infection caused by Toxoplasma gondii (T. gondii), an obligate and intracellular parasite, that affects both humans and animals globally. It can cause severe damage to neonates during pregnancy and immunocompromised patients. Therefore, finding a new method with high sensitivity for the diagnosis of toxoplasmosis that involves low-risk sampling is crucial for patient management. This study aims to diagnose toxoplasmosis in pregnant women from plasma, amniotic fluid, buffy coat, and urine specimens using serological, nested PCR, and real-time PCR tests. Methods: We collected amniotic fluid, blood, and urine samples from 100 pregnant women referred to a gynecologist in Mazandaran province, northern Iran, who were candidates for amniocentesis. We performed anti-T. gondii IgM, IgG, and IgG avidity tests using enzyme-linked immunosorbent assay (chemiluminescence, ELISA), as well as nested PCR, real-time PCR, and multilocus PCR genotyping using RE and GRA6 target genes, respectively. Results: Based on the serologic test, 52% of subjects were seropositive (51 samples were positive for IgG, and 1 was positive for both IgG and IgM antibodies), and all cases showed high avidity. Among 100 amniotic fluid samples, 2 and 3 cases tested positive using nested and real-time PCR, respectively, while all samples from buffy coat and urine were negative. All positive DNA samples were genotyped as type I. Conclusions Our study results suggest that diagnosing congenital toxoplasmosis is achievable using a combination of serological and molecular tests. We also found that the real-time PCR method is more sensitive than the nested PCR.

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A retrospective study of air quality associated with teratogenic pathogen screening in women of reproductive age in southern China

Chen

Zheng

Huang

et al. 2023

Environ Sci Pollut Res

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Evaluation of Toxoplasma gondii IgG avidity assays through a comparison of IgM serostatus

Cited by 5 publications

References 33 publications

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

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

In-house real-time PCR to detection Toxoplasma gondii in pregnant women candidates for amniocentesis and comparison with nested PCR and serologic methods in several clinical samples

A retrospective study of air quality associated with teratogenic pathogen screening in women of reproductive age in southern China

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