Toxoplasma gondii-specific IgG avidity testing in pregnant women

Background: When a pregnant woman contracts Toxoplasma gondii (T. gondii) infection during pregnancy, it may be vertically transmitted to the foetus. Information on the incidence of congenital toxoplasmosis (CT) in developing countries is scarce. Most studies focus on the seroprevalence of T. gondii infection among pregnant women. This study aimed to determine the seroprevalence of T. gondii infection among pregnant women attending public antenatal care in Windhoek, Namibia, in 2016.Methods: In this descriptive study, 344 urban pregnant women attending public antenatal care were voluntarily enrolled in the study. Seroprevalence of anti-T. gondii Immunoglobulin G (IgG) was determined by automated immunoassay. Samples with a positive T. gondii IgG result were tested for T. gondii Immunoglobulin M (IgM) and specific IgG avidity by using an enzyme-linked immunosorbent assay (ELISA) test. A questionnaire captured demographic data and exposure to risk factors. Data were analysed using Statistical Package for the Social Sciences (SPSS) and R.Results: Anti-T. gondii IgG was found in nine (2.61%) pregnant women. There was no association of anti-T. gondii IgG with demographic characteristics or exposure to risk factors.Anti-T. gondii IgM was positive in one (0.3%) woman, while three (0.9%) women had borderline anti-T. gondii IgM results. Specific IgG avidity was low, equivocal and high in 0%, 33% and 67% of seropositive pregnant women, respectively.Conclusion: Seroprevalence of anti-T. gondii IgG is much lower in Namibia than is reported in other developing countries. Investigation into specific IgM seropositivity and IgG avidity showed that pregnant women in the central region of Namibia are at low risk of vertical transmission and development of CT.

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Toxoplasma gondii specific IgG avidity assay: Role and implication in the confirmatory diagnosis of acute toxoplasmosis in seropositive pregnant women

Bangabandhu Sheikh Mujib Medical University Journal ◽

10.3329/bsmmuj.v9i2.29263 ◽

2016 ◽

Vol 9 (2) ◽

pp. 96

Author(s):

Chowdhury Rafia Naheen ◽

Shirin Tarafder ◽

Humayun Sattar ◽

Shafinaz Khan

Keyword(s):

Toxoplasma Gondii ◽

Pregnant Women ◽

Acute Infection ◽

High Avidity ◽

Past Infection ◽

Congenital Transmission ◽

Avidity Assay ◽

Igg Avidity ◽

Avidity Test ◽

Specific Igg

This study was undertaken to apply Toxoplasma gondii specific IgG avidity test in seropositive pregnant women to differentiate acute and past infection. T. gondii specific IgG avidity test was conducted in 39 seropositive pregnant women and their pregnancy outcomes were observed later on. Out of 39 T. gondii seropositive pregnant women 33 (84%) were only IgG positive and 6 (15.4%) were both IgG-IgM positive. All the IgG positive cases (100%) and 2(33.3%) IgG-IgM positive cases had high avidity antibodies and they gave birth to healthy babies. Rest of the 4 (66.7%) IgG-IgM positive women had low avidity and 50% of them had abortion and 50% gave birth to unhealthy babies. This reveals that the seropositive mothers having high IgG avidity had past infection and no risk of congenital transmission. Seropositive mothers having low IgG avidity had acute infection and so congenital transmission occurred. Presence of T. gondii specific IgG and IgM antibody does not indicate acute infection always. IgG-IgM positive pregnant women should be further evaluated by IgG avidity assay to confirm acute infection.

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Toxoplasmosis and pregnancy: Perinatal results and association of the IgG avidity test with congenital infection in pregnant women with positive anti-Toxoplasma gondii IgM [Abstract in English]

Scientia Medica ◽

10.15448/1980-6108.2010.1.6266 ◽

2010 ◽

Vol 20 (1) ◽

pp. 45

Author(s):

Virgílio Gonçalves de Souza-Júnior ◽

Ernesto Antonio Figueiró-Filho ◽

Danilo De Cerqueira Borges ◽

Vanessa Marcon Oliveira ◽

Lílian Rezende Coelho

Keyword(s):

Toxoplasma Gondii ◽

Pregnant Women ◽

Predictive Value ◽

Congenital Infection ◽

Neonatal Infection ◽

High Avidity ◽

Igg Avidity ◽

Risk Pregnancy ◽

Avidity Test ◽

Acute Toxoplasmosis

AIMS: To verify the perinatal outcomes in pregnant women with acute toxoplasmosis, and to determine if there was association between the results of Toxoplasma gondii-specific IgG avidity test and the presence or absence of fetal/neonatal infection. METHODS: A cross-sectional study included pregnant women with serological diagnosis of acute toxoplasmosis (presenting a positive Toxoplasma gondii-specific IgM test) attended at the outpatient unit for high-risk pregnancy of the Faculty of Medicine, Federal University of Mato Grosso do Sul, Brazil, in the period from November 2002 to November 2007. Test results demonstrating IgG avidity index above 30% were considered high avidity, while values below 30% were considered low avidity. Fetal and/or neonatal infection was defined by positive result for the polymerase chain reaction in amniotic fluid, or by a positive Toxoplasma gondii-specific IgM test in the newborn's serum. RESULTS: Considering all pregnant women referred to the outpatient unit for high-risk pregnancy in the period of study, frequency of pregnant women with positive Toxoplasma gondii-specific IgM was 10.8% (176/1.634). The rate of congenital infection in these patients was 4% (7/176). The IgG avidity test was performed in 162 patients (92% of the 176 pregnant women with positive IgM), and the avidity was high in 144 (88.9%). There was an association (p=0.003) between high avidity and no fetal/neonatal toxoplasmosis in our sample, with a prevalence ratio of 13.4 (confidence interval [CI] 95% 2.2-86.6). The positive predictive value of the avidity test (probability of congenital infection with a low avidity) was 22% (95% 6%-47%), while the negative predictive value (probability of absence of congenital infection with a high avidity) was 98% (95% CI 94% -99%). CONCLUSIONS: In this study the rate of congenital infection in pregnant women diagnosed with acute toxoplasmosis was 4%. In pregnant women with positive Toxoplasma gondii-specific IgM, results of Toxoplasma gondii-specific IgG avidity test were associated with the presence or absence of congenital infection, with a high negative predictive value (no fetal/neonatal infection when avidity was high).

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Toxoplasma gondii seroprevalence among pregnant women in Rabat, Morocco

Tropical Medicine and Health ◽

10.1186/s41182-021-00311-5 ◽

2021 ◽

Vol 49 (1) ◽

Author(s):

Majda Laboudi ◽

Zoubida Taghy ◽

Oussama Duieb ◽

François Peyron ◽

Abderrahim Sadak

Keyword(s):

Toxoplasma Gondii ◽

Pregnant Women ◽

Congenital Toxoplasmosis ◽

Immunoglobulin M ◽

Bivariate Analysis ◽

Enzyme Linked Immunosorbent Assay ◽

Seroprevalence Rate ◽

Recent Infection ◽

Igg Avidity ◽

Avidity Test

Abstract Background Toxoplasmosis is an infectious disease caused by a protozoan parasite named Toxoplasma gondii (T.gondii). Pregnant women are considered one of the risk groups. The objective of this retrospective study is to provide an updated estimate of the seroprevalence of anti-T. gondii antibodies among a group of Moroccan pregnant women monitored at the Parasitology Laboratory of the National Institute of Hygiene in Rabat in Morocco. Methods Serum samples were tested for the presence of specific anti-T. gondii immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies using indirect enzyme-linked immunosorbent assay (ELISA). Anti-Toxoplasma IgM- and IgG-positive cases were also evaluated with the anti-Toxoplasma IgG avidity test. All cases were evaluated according to the age, parity, and historical of abortion. Results Among 677 pregnant women, 94.1% (637/677) were serologically screened for the first time and therefore had no knowledge of their serological status, and only 5.9% (40/677) were screened for the second or third time. The overall anti-T. gondii IgG and IgM seropositivity among the 637 pregnant women included in the study analysis was 43% (274/637) and 3.9% (25/637), respectively. The use of the IgG avidity test allowed excluding recent infection among 83% of cases with IgG and IgM positive sera. The mean age was 29.4 ± 6.3 years. The result of the bivariate analysis revealed that the age influenced significantly the seroprevalence rate, while the parity and the existence of previous spontaneous abortion did not have any significant statistical correlation with seropositivity to T. gondii. Conclusion This study shows that 43% of pregnant women were positive and 57% of them had no antibody against the T. gondii infection. However, the pregnancy follow-up and the counseling of pregnant women remain essential for the prevention of congenital toxoplasmosis.

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Use of Toxoplasma gondi Specific IgG Avidity Assay for Diagnosis of Acquired Toxoplasmosis in Pregnant Women

International Journal of Infectious Diseases ◽

10.1016/j.ijid.2008.05.993 ◽

2008 ◽

Vol 12 ◽

pp. e375-e376

Author(s):

A. El-Moamly ◽

I. Al-Khalife ◽

M. El-Swify

Keyword(s):

Pregnant Women ◽

Avidity Assay ◽

Igg Avidity ◽

Specific Igg ◽

Acquired Toxoplasmosis

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Results of anti-Toxoplasma gondii IgG, IgM, IgA and IgG Avidity testing in pregnant women in Rome, Italy

Microbiologia Medica ◽

10.4081/mm.2012.2294 ◽

2012 ◽

Vol 27 (4) ◽

Author(s):

Carla Nisii ◽

Stefania Pane ◽

Giuseppina Liuzzi ◽

Ornella Butera ◽

Roberta Chiappini ◽

...

Keyword(s):

Toxoplasma Gondii ◽

Pregnant Women ◽

Igg Avidity

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Detection of Acute and Chronic Toxoplasma gondii Infection among Women with History of Abortion in the Southwest of Iran

Journal of Parasitology Research ◽

10.1155/2021/6693070 ◽

2021 ◽

Vol 2021 ◽

pp. 1-6

Author(s):

Jasem Saki ◽

Maryam Zamanpour ◽

Mahin Najafian ◽

Niloofar Mohammadpour ◽

Masoud Foroutan

Keyword(s):

Toxoplasma Gondii ◽

Pregnant Women ◽

Umbilical Cord ◽

Enzyme Linked Immunosorbent Assay ◽

High Avidity ◽

Normal Delivery ◽

Blood Samples ◽

Igg Avidity ◽

Avidity Test ◽

History Of

Background. Toxoplasma gondii (T. gondii) is one of the most common intracellular protozoan parasites, which can infect humans and a wide range of mammals and birds. The current study is aimed at investigating the occurrence of T. gondii infection in women with a history of abortion in Khuzestan, Iran. Materials and Methods. A total of 480 women with an abortion history, as well as 200 pregnant women with a normal delivery, were examined in this study. The blood, placenta, and umbilical cord blood samples were assessed by the enzyme-linked immunosorbent assay (ELISA) and nested-polymerase chain reaction (PCR) assay. Results. Based on the results of ELISA assay, the prevalence of toxoplasmosis was 30.83% in women with a history of abortion (25.62% with T. gondii IgG and 5.20% with T. gondii IgM). According to the IgG avidity test, 60.16% of IgG-positive samples showed high avidity, while 27.64% showed low avidity. On the other hand, the prevalence of toxoplasmosis in women with a normal delivery was 23% (21.5% with T. gondii IgG and 1.5% with T. gondii IgM). According to the IgG avidity test, 81.39% of these women showed high avidity, while only 4.65% showed low avidity. Based on the nested-PCR method, T. gondii DNA was detected in 14.18% of blood samples, 4.69% of placental samples, and 1.34% of umbilical cord samples, collected from 148 seropositive women with a history of abortion. Besides, using this method, the parasite DNA was identified in 4.34% of blood samples, collected from 46 seropositive women with a normal delivery, but not in any of the umbilical cord or placenta samples. Conclusion. The present results showed that T. gondii infection contributes to abortion in Khuzestan Province, Iran. Therefore, it is essential to investigate toxoplasmosis in pregnant women, especially in those who are seronegative, using molecular and serological methods and inform them about their disease and the associated risks.

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Anti-Toxoplasma gondii antibodies in pregnant women and their newborn infants in the region of São José do Rio Preto, São Paulo, Brazil

Sao Paulo Medical Journal ◽

10.1590/s1516-31802011000400010 ◽

2011 ◽

Vol 129 (4) ◽

pp. 261-266 ◽

Cited By ~ 7

Author(s):

Cinara de Cássia Brandão de Mattos ◽

Lígia Cosentino Junqueira Franco Spegiorin ◽

Cristina da Silva Meira ◽

Thaís da Costa Silva ◽

Ana Iara da Costa Ferreira ◽

...

Keyword(s):

Toxoplasma Gondii ◽

Pregnant Women ◽

Newborn Infants ◽

Sao Paulo ◽

Immunoglobulin M ◽

Enzyme Linked Immunosorbent Assay ◽

São Paulo ◽

Serum Samples ◽

Igm Antibodies ◽

Igg Avidity

CONTEXT AND OBJECTIVE: Toxoplasmosis transmission during pregnancy can cause severe sequelae in fetuses and newborns. Maternal antibodies may be indicators of risk or immunity. The aim here was to evaluate seropositivity for anti-Toxoplasma gondii (anti-T. gondii) immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies and IgG avidity in pregnant women and their newborn infants. DESIGN AND SETTING: Cross-sectional study in a high-risk pregnancy outpatient clinic. METHODS: Serum samples from pregnant women (n = 87) and their respective newborns (n = 87) were evaluated for anti-T. gondii antibodies using indirect immunofluorescence (IIF) (IgM and IgG), enzyme-linked immunosorbent assay (ELISA) (IgG) and an avidity test. RESULTS: Anti-T. gondii antibodies were identified in 64.4% of the serum samples from the mothers and their infants (56/87). Except for two maternal serum samples (2.3%), all others were negative for anti-T. gondii IgM antibodies, using IIF. The results showed that 92.9% of the pregnant women had high IgG avidity indexes (> 30%) and four samples had avidity indexes between 16 and 30%. Two women in the third trimester of pregnancy were positive for anti-T. gondii IgM antibodies; their babies had avidity indexes between 16 and 30%. The avidity indexes of serum from the other 83 newborns were similar to the results from their mothers. CONCLUSIONS: The results showed that 2% of the pregnant women were at risk of T. gondii transmission during the gestational period. These data seem to reflect the real situation of gestational toxoplasmosis in the northwestern region of the state of São Paulo.

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