Polymerase chain reaction in the diagnosis of congenital toxoplasmosis: more than two decades of development and evaluation

Prevalence and risk factors of Toxoplasma gondii infection among women with miscarriage and their aborted fetuses in the northwest of Iran

Toxoplasmosis is a worldwide disease of various animals and human and results from infection with the Toxoplasma gondii parasite. Abortion and congenital defects are important consequences of the T. gondii infection. The aim of this study was to determine the Toxoplasma-induced abortions among women with miscarriage and the presence of T. gondii in their aborted fetuses in Urmia, the northwest of Iran. This cross-sectional study was conducted with 215 women with abortion and their aborted fetuses, from 2020 to 2021. Seroprevalence of anti-Toxoplasma IgG and IgM were determined using the sera of the aforesaid women. Nested PCR was carried out using RE-529 gene sequences, and sequencing was performed using the T. gondii GRA6 gene on the remnant of pregnancy after abortion. The tissue positive samples were then subjected to another PCR on GRA6 gene and sequenced for genotyping. Among 215 serum samples of women with abortion, 70 (32.6%) were positive for anti-Toxoplasma IgG, and three (1.4%) were positive for IgM. The RE-529 sequence of T. gondii was positive in three (1.4%) of the aborted fetuses. The analysis of GRA6 gene indicated that all three positive samples carried a GRA6 allele (GRA6I) of T. gondii type I genotype. Our findings suggest that T. gondii is one of the causative agents of spontaneous abortion in West Azerbijan Province, the northwest of Iran.

Knowledge of gynecologists in the public health system care of women victims of violence

OBJECTIVE:

This study aimed to evaluate the knowledge of the obstetricians and gynecologists in the care of women victims of violence in the public health system and the existence of institutional mechanisms to support them.

METHODS:

A cross-sectional and observational study was conducted with an electronic questionnaire by physicians who provided care in the obstetrics and gynecology emergency unit of the public health system. This study aimed to identify the care for victims of violence who received the institutional mechanisms of support, the difficulties encountered in determining the appropriate care, and estimates of the prevalence of violence against women.

RESULTS:

Notably, 92 physicians responded to the questionnaire. Of these, 85% had already provided care in one or more cases of violence, and 60% believed that <20% of the women received adequate care in these cases, mainly due to the short-time frame of the consultation, lack of team preparation, and lack of institutional resources. A total of 61% of the participants believed that they were not prepared to provide adequate care in those cases.

CONCLUSIONS:

Most of the physicians interviewed, although reported to have sufficient knowledge to adequately treat victims of violence, did not provide such care due to lack of institutional support.

Ocular toxoplasmosis: a review of the current diagnostic and therapeutic approaches

PURPOSE

This review aims to summarize the current knowledge concerning the clinical features, diagnostic work-up and therapeutic approach of ocular toxoplasmosis focusing mainly on the postnatally acquired form of the disease.

METHODS

A meticulous literature search was performed in the PubMed database. A supplementary search was made in Google Scholar to complete the collected items.

RESULTS

Ocular toxoplasmosis is one of the most frequent infectious etiologies of posterior uveitis. It typically presents with retinochoroiditis. Setting an accurate diagnosis depends to a considerable degree on detecting characteristic clinical characteristics. In addition to the evaluation of clinical features, the diagnosis of toxoplasmosis relies at a large degree on serologic testing. The detection of the parasite DNA in the aqueous or vitreous humor can provide evidence for a definitive diagnosis. The current mainstay for the treatment, if necessary, is the use of oral antibiotic with systemic corticosteroids. Recent evidence suggests other therapeutic approaches, such as intravitreal antibiotics can be used.

CONCLUSION

Recent developments in the diagnostic and therapeutic approach have contributed to preventing or limiting vision loss of patients suffering from ocular toxoplasmosis. Further studies are required to provide a better understanding of epidemiology, pathogenesis, diagnosis, and treatment with a significant impact on the management of this challenging clinical entity.

A pilot study on screening for gestational/congenital toxoplasmosis of pregnant women at delivery in the Eastern Province of Saudi Arabia

BACKGROUND

Globally, congenital toxoplasmosis remains a significant cause of morbidity and mortality, and outbreaks of T. gondii infection represent a major public health threat, especially in developing countries. Evidence in the literature indicates that only a few studies have been conducted on the incidence of maternal and congenital toxoplasmosis in Saudi Arabia. This prospective study aims to measure the overall incidence of congenital toxoplasmosis, both patent and 'silent' infection, among pregnant women in the Eastern Province of Saudi Arabia. The study would attempt to relate the cord blood results with the time of seroconversion in the mother, underlining the importance of early intervention in such cases.

METHODS

Five hundred paired maternal/cord blood samples were tested for anti-Toxoplasma IgG or IgM antibodies. Samples were collected during delivery from mother and newborn (cord blood) from November 2011 to May 2012. Only positive for anti-Toxoplasma IgG or/and IgM cord blood was processed for real-time PCR for confirmation. The age of mothers ranged from 16 to 45 years.

RESULTS

The sample subjects were tested during child delivery for specific IgG and IgM antibodies against Toxoplasmosis, of which 21.0% (n = 105) mother/baby pairs were found serologically positive for anti-Toxoplasma IgG antibodies. The rate of maternal seropositivity for anti-Toxoplasma IgM antibodies was found among 4 participants (0.8%), who were also seropositive for anti-Toxoplasma IgG antibodies. None of the children tested positive for anti-Toxoplasma IgM antibodies, even those born to mothers with IgM positive. All 105 cord blood tests in the study sample were confirmed negative by real-time PCR. The seroprevalence of Toxoplasma IgG antibodies increased with maternal age, parity, and was significantly higher in women who gave birth to children with congenital anomalies (p = 0.008).

CONCLUSION

The findings of the current study indicate a dire need to develop and implement preventive programs against Toxoplasma gondii infection, as well as a health education program on how to avoid toxoplasmosis for all seronegative women during pregnancy.

An updated literature review on maternal-fetal and reproductive disorders of Toxoplasma gondii infection

BACKGROUND

Toxoplasma gondii infection is one of the most prevalent infectious disease with worldwide distribution. Congenital toxoplasmosis is annually responsible for 1.20 million disability-adjusted life years around the world, but often it is overlooked many countries.

METHODS

We performed an updated review to summarize the current researches on fetal, neonatal and maternal consequences of T. gondii infection and also adverse effects of toxoplasmosis on women reproductive organs.

RESULTS

T. gondii infection could be cause of several abnormalities from hydrocephalus, microcephaly, deafness, abortion and still birth in fetal to psychomotor retardation, intellectual disability, hearing loss, slower postnatal motor development during the first year of life; and chorioretinitis, cryptogenic epilepsy and autism spectrum disorders in newborns. Moreover, this infection is related with neuropsychiatric disorders such as anxiety, schizophrenia spectrum disorders, depression, decreased weight, autoimmune thyroid diseases, self-directed violence, violent suicide attempts in mothers. This literature review emphasized that toxoplasmosis could be an important neglected factor endometritis, ovarian dysfunction, impaired folliculogenesis, ovarian and uterine atrophy, decrease in reproductive organs weight and reproductive performance in women. We reviewed role of the immunological profile such as pro-infiammatory cytokines and hormonal changes as main potential mechanisms related to this infection and development of maternal-fetal and reproductive disorders.

CONCLUSION

T. gondii is associated with several brain related disorders in both mothers and newborns, and also it is cause of several abnormalities in reproductive organs. Early diagnosis and treatment of the infection could be effective to significantly improve the clinical outcome.

Molecular diagnosis of Toxoplasma gondii infection in Libya

Background

Toxoplasma gondii infections are prevalent in humans and animals throughout Libya. Current diagnosis is based on detection of Toxoplasma-specific IgM and IgG. In this study, we established and optimized a diagnostic PCR assay for molecular diagnosis of T. gondii in Libya.

Methods

From January to December, 2010, 177 blood and serum samples were collected from suspected patients. This includes: 140 women who have had spontaneous abortions, 26 HIV-positive patients, nine patients with leukemia and lymphoma, and two infants with ocular infection. Samples were screened for anti-Toxoplasma IgG and IgM antibodies before DNA extraction. The surface antigen gene 2 (SAG2) was targeted in a semi-nested PCR to amplify a 999 bp and a 614 bp fragment in the first and the second run respectively.

Results

A total of 54/140 (38.5 %) women who have had spontaneous abortions, 23/26 (88 %) HIV patients, 6/9 (66.6 %) of the leukaemia and lymphoma patients, and one child with ocular infection were seropositive for anti-Toxoplasma IgG and/or IgM. Genomic DNA was extracted from 38 selected seropositive samples. The PCR was sensitive enough to detect DNA concentration of 12 ng/μL. PCR analysis was performed for 38 selected seropositive patients (16 women who have had spontaneous abortions, 15 positive HIV patients, six leukaemia patients and one child with ocular infection). Our designed primers were successfully amplified in 22/38 (57.9 %) samples; 5/12 (35.7 %) from serum and 17/26 (65.8 %) from whole blood samples. All PCR positive samples were IgG-positive except two samples which were IgM and IgG & IgM-positive serum samples respectively. The semi-nested PCR confirmed five more samples. These included two leukaemia and two HIV-positive whole blood samples and one serum sample from an aborted woman.

Conclusion

The ability of PCR to diagnose active toxoplasmosis is needed in immunocompromised patients and congenital toxoplasmosis cases, especially when serological techniques fail. For the first time in Libya, we established and optimized semi-nested PCR of SAG2 gene. The developed PCR method was able to detect as little as 12 ng/μL of T. gondii DNA and was useful to diagnose the diseases in women who have had spontaneous abortions, HIV-positive patients, patients with leukemia and lymphoma, and infants with ocular infection.

Toxoplasmosis-associated abortion and stillbirth in Tehran, Iran

OBJECTIVES

This study was aimed to evaluate the role of toxoplasmosis in etiology of abortion and stillbirth based on molecular and serological techniques.

MATERIAL AND METHODS

A total of 110 pregnant women with abortion and stillbirth were enrolled as the case group, and 110 pregnant women with normal delivery were enrolled as the control group. Serological and molecular detections of Toxoplasma gondii were assessed by ELISA and PCR methods.

RESULTS

The seroprevalence of IgG was 25.5% in the case group (26.8% in abortion and 21.4% in stillbirth) and 26.4% in the control group. IgM seropositivity was detected in 2.7% of the case group (3.6% in abortion and 0% in stillbirth) and 0.9% of the control group (p = 0.37). Toxoplasma gondii DNA was detected in 6.4% of the case group (7.3% in abortion and 3.6% in stillbirth) and 1.8% of the control group by PCR (p = 0.17). The major risk factor of congenital toxoplasmosis was the history of eating undercooked meat (p = 0.06).

CONCLUSION

Results of this study revealed that the rate of PCR positive in women with abortion and stillbirth was 3.7 times higher than that in normal delivery, but the difference was not statistically significant. These findings suggest that toxoplasmosis can be involved in etiology of abortion and stillbirth.

Amniocentesis for the detection of congenital toxoplasmosis: results from the nationwide Austrian prenatal screening program

Prenatal diagnosis of congenital toxoplasmosis (CT) influences therapeutical management in pregnant women and their offspring. In Austria, a nationwide serological healthcare program to identify potential maternal toxoplasma infections during pregnancy exists. We assessed the clinical use of amniocentesis for toxoplasma-specific polymerase chain reaction (PCR) on amniotic fluid to detect CT. Data on serology, amniocentesis, PCR, complications, treatment, and paediatric clinical outcome were collected retrospectively among the birth cohort 1992-2008. There were 1386 women with amniocentesis, but only in 707 cases (51%) was acute maternal infection confirmed serologically. A high proportion (49%) of amniocenteses with negative PCR results in women with chronic infection or seronegativity were performed without clinical justification for the women or their foetuses. The positive and negative predictive values of PCR were 94.4% and 99.3%, respectively. Thirty-nine foetuses with CT, including four deaths, were reported. The five PCR-negative but infected infants were identified by the serological and clinical follow-up program. Thirty percent of amniocenteses were performed in the third trimester, and gestational age or treatment did not influence PCR sensitivity. Amniocentesis is indicated in women with acute maternal infection, and facilitated targeted therapies in pregnant women and their offspring. In women with late toxoplasma infection, negative amniotic fluid PCR made treatment of infants unnecessary. Serological and clinical follow-up of infants is important to confirm the infection status of the infant. Recommendations, based on our 17-year experience, to improve the current diagnostic strategies and to reduce unnecessary amniocentesis, are given.

Toxoplasmosis

Toxoplasma gondii, an Apicomplexan, is a pathogic protozoan that can infect the central nervous system. Infection during pregnancy can result in a congenial infection with severe neurological sequelae. In immunocompromised individuals reactivation of latent neurological foci can result in encephalitis. Immunocompetent individuals infected with T. gondii are typically asymptomatic and maintain this infection for life. However, recent studies suggest that these asymptomatic infections may have effects on behavior and other physiological processes. Toxoplasma gondii infects approximately one-third of the world population, making it one of the most successful parasitic organisms. Cats and other felidae serve as the definite host producing oocysts, an environmentally resistant life cycle stage found in cat feces, which can transmit the infection when ingested orally. A wide variety of warm-blooded animals, including humans, can serve as the intermediate host in which tissue cysts (containing bradyzoites) develop. Transmission also occurs due to ingestion of the tissue cysts. There are three predominant clonal lineages, termed Types I, II and III, and an association with higher pathogenicity with the Type I strains in humans has emerged. This chapter presents a review of the biology of this infection including the life cycle, transmission, epidemiology, parasite strains, and the host immune response. The major clinical outcomes of congenital infection, chorioretinitis and encephalitis, and the possible association of infection of toxoplasmosis with neuropsychiatric disorders such as schizophrenia, are reviewed.

A review on human toxoplasmosis

Toxoplasmosis is a worldwide infection caused by the intracellular parasite Toxoplasma gondii. At least a third of the world human population are infected with the parasite, making it one of the most successful parasitic infections. Primary maternal infection may cause health-threatening sequelae for the foetus, or even cause death in uterus. Reactivation of a latent infection in immune deficiency conditions such as AIDS and organ transplantation can cause fatal toxoplasmic encephalitis. Toxoplasmosis is a major cause of retinochoroiditis, especially in individuals with an impaired immune system. Despite the usually 'asymptomatic' nature of the infection, a significant burden imposed by the parasite necessitates the implementation of effective means for the prevention, diagnosis, and management of this disease. Laboratory diagnosis, i.e. PCR and serologic assays, plays the main role in the diagnosis of congenital infection and assists in the confirmatory diagnosis of toxoplasmic encephalitis and ocular toxoplasmosis. Here, we briefly review general aspects of Toxoplasma infection and focus on the diagnostic methods currently used in medical laboratories for the diagnosis of Toxoplasma infection.