The Importance of IgG Avidity and the Polymerase Chain Reaction in Treating Toxoplasmosis during Pregnancy: Current Knowledge

Recent and past toxoplasmosis infections, associated factors, and awareness among pregnant women in Nigeria

Objectives

The study determined the rate of recent and past Toxoplasma gondii infections, associated factors, and awareness among expectant mothers assessing antenatal care in a tertiary hospital in Nigeria.

Methods

This prospective cohort study was conducted among pregnant women. A questionnaire was used to gather information on socio-demographics, infection risk factors, and awareness of the infection. Using an ELISA kit, the IgG and IgM antibodies against Toxoplasma gondii were assessed in blood samples from these women. For samples that tested positive for IgM, a real-time polymerase chain reaction was used to amplify the DNA. SPSS version 23 was used for data entry and analysis. The p-value < 0.05 was adjudged to be significant.

Results

A total of 250 pregnant women participated in the study. The rate of recent infection (IgM antibody positivity) was 3.6% (9/250), while past infection (IgG antibody positivity) was 68.4% (171/250). Polymerase chain reaction confirmed 5/9 recent infections as positive. Factors significantly associated with toxoplasmosis were gardening (p = 0.037) and undercooked meat (p = 0.023). Only 27 out of 250 pregnant women in this research had heard of toxoplasmosis, which translates to a low awareness rate of 10.8%.

Conclusions

The recent infection among pregnant women in this study indicates the possibility of mother-to-child transmission with attendant sequelae. There was a significant association between past Toxoplasmosis gondii infections and stillbirth. Routine screening for toxoplasmosis should be incorporated into the antenatal program since none of the symptoms could significantly predict illness. In addition, regular antennal care instruction should cover toxoplasmosis education.

Review on the Current Trends of Toxoplasmosis Serodiagnosis in Humans

Toxoplasmosis is a widely distributed zoonotic infection caused by the obligate intracellular apicomplexan parasite Toxoplasma gondii. It is mainly transmitted through the ingestion of oocysts shed by an infected cat acting as its definitive host. The key to effective control and treatment of toxoplasmosis is prompt and accurate detection of T. gondii infection. Several laboratory diagnostic methods have been established, including the most commonly used serological assays such as the dye test (DT), direct or modified agglutination test (DAT/MAT), indirect hemagglutination test (IHA), latex agglutination test (LAT), indirect immunofluorescent test (IFAT), enzyme-linked immunosorbent assays (ELISA), immunochromatographic tests (ICT), and the western blot. Nonetheless, creating specific and reliable approaches for serodiagnosis of T. gondii infection, and differentiating between acute and chronic phases of infection remains a challenge. This review provides information on the current trends in the serodiagnosis of human toxoplasmosis. It highlights the advantages of the use of recombinant proteins for serological testing and provides insight into the possible future direction of these methods.

Congenital toxoplasmosis and proposal of a new classification for the likelihood of primary maternal infection: analysis of 375 cases in Southeast Italy

Objective: The aim of this study was to propose a classification in order to stratify the probability of an acute Toxoplasma infection in pregnancy and to estimate the risk of vertical transmission.Study design: We evaluated the likelihood of a primary maternal infection according to the Lebech classification and to the modified-Lebech classification proposed for our group of 375 patients referred for a suspected primary maternal infection. Fetal diagnosis included the examination of amniotic fluid by PCR to detect Toxoplasma DNA as a confirmation test.Results: Differences between the old and new classification resulted statistically significant for old classes defined as probable and unlikely with a clear shift of cases from the unlikely to the probable class in the new classification. Transmission rate showed a significant (p < .05) increase of the transmission rate in the probable class in our new classification as compared with the Lebech one.Conclusions: Results obtained in the present study suggest that the new IgG avidity-based classification herein proposed could estimate more precisely the likelihood of a primary maternal Toxoplasma infection as well as the risk of fetal infection, when compared with the historical Lebech Classification.

Prematurity and Low Birth Weight did not Correlate with Anti-Toxoplasma gondii Maternal Serum Profiles--a Brazilian Report

Gestational Toxoplasma gondii infection is considered a major risk factor for miscarriage, prematurity and low birth weight in animals. However, studies focusing on this topic in humans are scarce. The objective of this study is to determine whether anti-Toxoplasma gondii maternal serum profiles correlate prematurity and low birth weight in humans. The study examined 213 pregnant women seen at the High-Risk Pregnancy Hospital de Base, São José do Rio Preto, São Paulo, Brazil. All serological profiles (IgM-/IgG+; IgM-/IgG-; IgM+/IgG+) were determined by ELISA commercial kits. Maternal age, gestational age and weight of the newborn at birth were collected and recorded in the Statement of Live Birth. Prematurity was defined as gestational age <37 weeks and low birth weight ≤ 2499 grams. The t-test was used to compare values (p < 0.05). The mean maternal age was 27.6±6.6 years. Overall, 56.3% (120/213) of the women studied were IgM-/IgG+, 36.2% (77/213) were IgM-/IgG- and 7.5% (16/213) were IgM+/IgG+. The average age of the women with serological profile IgM+/IgG+ (22.3±3.9 years) was different from women with the profile IgM-/IgG+ (27.9±6.7 years, p = 0.0011) and IgM-/IgG- (27.9±6.4 years, p = 0.0012). There was no statistically significant difference between the different serological profiles in relation to prematurity (p = 0.6742) and low birth weight (p = 0.7186). The results showed that prematurity and low birth weight did not correlate with anti-Toxoplasma gondii maternal serum profiles.