Evaluation of the LDBIO point of care test for the combined detection of toxoplasmic IgG and IgM

Identification of novel biomarkers for anti-Toxoplasma gondii IgM detection and the potential application in rapid diagnostic fluorescent tests

Toxoplasmosis, while often asymptomatic and prevalent as a foodborne disease, poses a considerable mortality risk for immunocompromised individuals during pregnancy. Point-of-care serological tests that detect specific IgG and IgM in patient sera are critical for disease management under limited resources. Despite many efforts to replace the T. gondii total lysate antigens (TLAs) by recombinant antigens (rAgs) in commercial kits, while IgG detection provides significant specificity and sensitivity, IgM detection remains comparatively low in sensitivity. In this study, we attempted to identify novel antigens targeting IgM in early infection, thereby establishing an IgM on-site detection kit. Using two-dimensional gel electrophoresis (2DE) and mouse serum immunoblotting, three novel antigens, including EF1γ, PGKI, and GAP50, were indicated to target T. gondii IgM. However, rAg EF1γ was undetectable by IgM of mice sera in Western blotting verification experiments, and ELISA coated with PGKI did not eliminate cross-reactivity, in contrast to GAP50. Subsequently, the lateral flow reaction employing a strip coated with 0.3 mg/mL purified rAg GAP50 and exhibited remarkable sensitivity compared with the conventional ELISA based on tachyzoite TLA, which successfully identified IgM in mouse sera infected with tachyzoites, ranging from 103 to 104 at 5 dpi and 104 at 7 dpi, respectively. Furthermore, by using standard T. gondii-infected human sera from WHO, the limit of detection (LOD) for the rapid fluorescence immunochromatographic test (FICT) using GAP50 was observed at 0.65 IU (international unit). These findings underline the particular immunoreactivity of GAP50, suggesting its potential as a specific biomarker for increasing the sensitivity of the FICT in IgM detection.

Novel paradigm enables accurate monthly gestational screening to prevent congenital toxoplasmosis and more

BACKGROUND

Congenital toxoplasmosis is a treatable, preventable disease, but untreated causes death, prematurity, loss of sight, cognition and motor function, and substantial costs worldwide.

OBJECTIVES

We asked whether high performance of an Immunochromatographic-test (ICT) could enable accurate, rapid diagnosis/treatment, establishing new, improved care-paradigms at point-of-care and clinical laboratory.

METHODS

Data were obtained in 12 studies/analyses addressing: 1-feasibility/efficacy; 2-false-positives; 3-acceptability; 4-pink/black-line/all studies; 5-time/cost; 6-Quick-Information/Limit-of-detection; 7, 8-acute;-chronic; 9-epidemiology; 10-ADBio; 11,12-Commentary/Cases/Chronology.

FINDINGS

ICT was compared with gold-standard or predicate-tests. Overall, ICT performance for 1093 blood/4967 sera was 99.2%/97.5% sensitive and 99.0%/99.7% specific. However, in clinical trial, FDA-cleared-predicate tests initially caused practical, costly problems due to false-positive-IgM results. For 58 persons, 3/43 seronegative and 2/15 chronically infected persons had false positive IgM predicate tests. This caused substantial anxiety, concerns, and required costly, delayed confirmation in reference centers. Absence of false positive ICT results contributes to solutions: Lyon and Paris France and USA Reference laboratories frequently receive sera with erroneously positive local laboratory IgM results impeding patient care. Therefore, thirty-two such sera referred to Lyon's Reference laboratory were ICT-tested. We collated these with other earlier/ongoing results: 132 of 137 USA or French persons had false-positive local laboratory IgM results identified correctly as negative by ICT. Five false positive ICT results in Tunisia and Marseille, France, emphasize need to confirm positive ICT results with Sabin-Feldman-Dye-test or western blot. Separate studies demonstrated high performance in detecting acute infections, meeting FDA, CLIA, WHO REASSURED, CEMark criteria and patient and physician satisfaction with monthly-gestational-ICT-screening.

CONCLUSIONS/SIGNIFICANCE

This novel paradigm using ICT identifies likely false positives or raises suspicion that a result is truly positive, rapidly needing prompt follow up and treatment. Thus, ICT enables well-accepted gestational screening programs that facilitate rapid treatment saving lives, sight, cognition and motor function. This reduces anxiety, delays, work, and cost at point-of-care and clinical laboratories.

TRIAL REGISTRATION

NCT04474132, https://clinicaltrials.gov/study/NCT04474132 ClinicalTrials.gov.

Performances of ICT Toxoplasma IgG-IgM test in comparison with Vidas® toxo competition to determine the immune status against Toxoplasma gondii

Toxoplasmosis is a ubiquitous parasitic infection caused by Toxoplasma gondii (Tg). In immunocompetent people, the infection may be asymptomatic with the induction of an immune response that may prevent reinfection or transmission to the fetus in immune pregnant woman. In immunocompromised persons or seronegative pregnant woman with a primary infection during pregnancy, the infection may result in the loss of life, sight, cognition, and motor function in the immune-compromised person or immunologically immature fetus. The objective of this study was to evaluate a new immunochromatographic test Toxoplasma ICT IgG-IgM (ICT) that allows detection of specific anti-Tg immunoglobulins G (Ig G) and M (Ig M). We included 1145 prospectively obtained sera and 376 samples selected for specificity or sensitivity studies. The performance of ICT was compared using Vidas® Toxo Competition (TXC) and Toxoscreen®. In case of discrepancy, Vidas® Toxo Ig G or Ig M and LDBIO Toxo II IgG western blot were used to establish definitive results by additional methods. Sensitivity and specificity of ICT were respectively 99.3% and 100%. In comparison, Toxoscreen®'s sensitivity was 100% and the specificity was 99.8%. TXC had a sensitivity of 98.7% with a specificity of 99.1%. ICT has excellent performance even for low Ig G titers, especially in immunocompromised patients, and confirms the specificity of isolated Ig M. This ICT provides reliable results easily and quickly. This screening technique is not designed to differentiate the Ig M from Ig G. When positive, additional tests may be necessary.

Systemic Immunomodulatory Effects of Codonopsis pilosula Glucofructan on S180 Solid-Tumor-Bearing Mice

The immune functions of the body are intricately intertwined with the onset and advancement of tumors, and immunotherapy mediated by bioactive compounds has exhibited initial effectiveness in overcoming chemotherapy resistance and inhibiting tumor growth. However, the comprehensive interpretation of the roles played by immunologic components in the process of combating tumors remains to be elucidated. In this study, the Codonopsis pilosula glucofructan (CPG) prepared in our previous research was employed as an immunopotentiator, and the impacts of CPG on both the humoral and cellular immunity of S180 tumor-bearing mice were investigated. Results showed that CPG administration of 100 mg/kg could effectively inhibit tumor growth in mice with an inhibitory ratio of 45.37% and significantly improve the expression of Interleukin-2 (IL-2), Interferon-γ (IFN-γ), and Tumor Necrosis Factor-α (TNF-α). Additionally, CPG clearly enhanced B-cell-mediated humoral immunity and immune-cell-mediated cellular immunity, and, finally, induced S180 cell apoptosis by arresting cells in the G0/G1 phase, which might result from the IL-17 signaling pathway. These data may help to improve comprehension surrounding the roles of humoral and cellular immunity in anti-tumor immune responses.

Novel paradigm enables accurate monthly gestational screening to prevent congenital toxoplasmosis and more

Background

Congenital toxoplasmosis is a treatable, preventable disease, but untreated causes death, prematurity, loss of sight, cognition and motor function, and substantial costs worldwide.

Methods/Findings

In our ongoing USA feasibility/efficacy clinical trial, data collated with other ongoing and earlier published results proved high performance of an Immunochromatographic-test(ICT) that enables accurate, rapid diagnosis/treatment, establishing new paradigms for care. Overall results from patient blood and/or serum samples tested with ICT compared with gold-standard-predicate-test results found ICT performance for 4606 sera/1876 blood, 99.3%/97.5% sensitive and 98.9%/99.7% specific. However, in the clinical trial the FDA-cleared-predicate test initially caused practical, costly problems due to false-positive-IgM results. For 58 persons, 3/43 seronegative and 2/15 chronically infected persons had false positive IgM predicate tests. This caused substantial anxiety, concerns, and required costly, delayed confirmation in reference centers. Absence of false positive ICT results contributes to solutions: Lyon and Paris France and USA Reference laboratories frequently receive sera with erroneously positive local laboratory IgM results impeding patient care. Therefore, thirty-two such sera referred to Lyon's Reference laboratory were ICT-tested. We collated these with other earlier/ongoing results: 132 of 137 USA or French persons had false positive local laboratory IgM results identified correctly as negative by ICT. Five false positive ICT results in Tunisia and Marseille, France, emphasize need to confirm positive ICT results with Sabin-Feldman-Dye-test or western blot. Separate studies demonstrated high performance in detecting acute infections, meeting FDA, CLIA, WHO ASSURED, CEMark criteria and patient and physician satisfaction with monthly-gestational-ICT-screening.

Conclusions/Significance

This novel paradigm using ICT identifies likely false positives or raises suspicion that a result is truly positive, rapidly needing prompt follow up and treatment. Thus, ICT enables well-accepted gestational screening programs that facilitate rapid treatment saving lives, sight, cognition and motor function. This reduces anxiety, delays, work, and cost at point-of-care and clinical laboratories.

Author’s Summary

Toxoplasmosis is a major health burden for developed and developing countries, causing damage to eyes and brain, loss of life and substantial societal costs. Prompt diagnosis in gestational screening programs enables treatment, thereby relieving suffering, and leading to > 14-fold cost savings for care. Herein, we demonstrate that using an ICT that meets WHO ASSURED-criteria identifying persons with/without antibody to Toxoplasma gondii in sera and whole blood with high sensitivity and specificity, is feasible to use in USA clinical practice. We find this new approach can help to obviate the problem of detection of false positive anti- T.gondii IgM results for those without IgG antibodies to T.gondii when this occurs in present, standard of care, predicate USA FDA cleared available assays. Thus, this accurate test facilitates gestational screening programs and a global initiative to diagnose and thereby prevent and treat T.gondii infection. This minimizes likelihood of false positives (IgG and/or IgM) while maintaining maximum sensitivity. When isolated IgM antibodies are detected, it is necessary to confirm and when indicated continue follow up testing in ∼2 weeks to establish seroconversion. Presence of a positive ICT makes it likely that IgM is truly positive and a negative ICT makes it likely that IgM will be a false positive without infection. These results create a new, enthusiastically-accepted, precise paradigm for rapid diagnosis and validation of results with a second-line test. This helps eliminate alarm and anxiety about false-positive results, while expediting needed treatment for true positive results and providing back up distinguishing false positive tests.

Evaluation of the acceptability of point of care diagnostic test for prenatal toxoplasmosis (translational research phase III)

BACKGROUND

A new point of care test (POC) was developed that is promising as a tool to enhance impact of prenatal care programs for toxoplasmosis, however, no reports exist about its use or acceptability for healthcare personnel and mothers in Colombia.

METHODS

This was a translational research - phase III study of the acceptability of a new POC test (Toxoplasma ICT IgG-IgM, LDBio) for qualitative diagnosis of toxoplasmosis in 783 pregnant women and 30 health personnel in primary health care sites in the city of Armenia, Quindío (Colombia). Along with collection of the results of diagnostic POC and confirmatory test and demographic information, we evaluated acceptability through measure of the willingness, credibility, and satisfaction by using questionnaires with a Likert scale during routine prenatal care visits.

RESULTS

POC positivity was 46.5% among pregnant participants and was significantly related to socioeconomic factors, including education level (p = 0.00000000) and insurance status (p = 0.00000015). A total of 93-97% of healthcare personnel indicated agreement to positive statements regarding total satisfaction and total credibility of the LDBio test, but qualitative questions identified "Difficulty in the test procedure" as the most common response about barriers to apply the test. Greater than 90% of pregnant participants agree that POC test should be routine for all pregnant woman and permanently implemented.

CONCLUSIONS

The test had near complete acceptability. In future studies it is necessary to examine the effect of non-differentiation between IgG and IgM isotypes.

Building Programs to Eradicate Toxoplasmosis Part I: Introduction and Overview

Purpose of Review

Review building of programs to eliminate Toxoplasma infections.

Recent Findings

Morbidity and mortality from toxoplasmosis led to programs in USA, Panama, and Colombia to facilitate understanding, treatment, prevention, and regional resources, incorporating student work.

Summary

Studies foundational for building recent, regional approaches/programs are reviewed. Introduction provides an overview/review of programs in Panamá, the United States, and other countries. High prevalence/risk of exposure led to laws mandating testing in gestation, reporting, and development of broad-based teaching materials about Toxoplasma. These were tested for efficacy as learning tools for high-school students, pregnant women, medical students, physicians, scientists, public health officials and general public. Digitized, free, smart phone application effectively taught pregnant women about toxoplasmosis prevention. Perinatal infection care programs, identifying true regional risk factors, and point-of-care gestational screening facilitate prevention and care. When implemented fully across all demographics, such programs present opportunities to save lives, sight, and cognition with considerable spillover benefits for individuals and societies.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40124-022-00269-w.

Building Programs to Eradicate Toxoplasmosis Part IV: Understanding and Development of Public Health Strategies and Advances “Take a Village”

Purpose of Review

Review international efforts to build a global public health initiative focused on toxoplasmosis with spillover benefits to save lives, sight, cognition and motor function benefiting maternal and child health.

Recent Findings

Multiple countries’ efforts to eliminate toxoplasmosis demonstrate progress and context for this review and new work.

Summary

Problems with potential solutions proposed include accessibility of accurate, inexpensive diagnostic testing, pre-natal screening and facilitating tools, missed and delayed neonatal diagnosis, restricted access, high costs, delays in obtaining medicines emergently, delayed insurance pre-approvals and high medicare copays taking considerable physician time and effort, harmful shortcuts being taken in methods to prepare medicines in settings where access is restricted, reluctance to perform ventriculoperitoneal shunts promptly when needed without recognition of potential benefit, access to resources for care, especially for marginalized populations, and limited use of recent advances in management of neurologic and retinal disease which can lead to good outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40124-022-00268-x.

Congenital toxoplasmosis: Should we still care about screening?

Prenatal systematic screening for congenital toxoplasmosis has been performed in Austria and France since 1975 and neonatal screening for congenital toxoplasmosis has been part of the New England Newborn screening program since 1986.

In this narrative review we review the data leading up to the systematic screening programs in Austria and France, highlighting the main finding of the European Union funded research in the 1990s and early 2000s. Different descriptive studies of the effect of pre- or postnatal treatment are discussed. Toxoplasma gondii has different genetic lineages with different pathogenicity in humans. This means that results in areas with a low pathogenic lineage cannot be extrapolated to an area with highly pathogenic lineages. The importance of meat as a source of infection is discussed in the light of an increased prevalence of T.gondii in organic livestock production .

High performance of a novel point-of-care blood test for Toxoplasma infection in women from diverse regions of Morocco

Point-of-care (POC) testing for Toxoplasma infection has the potential to revolutionize diagnosis and management of toxoplasmosis, especially in high-risk populations in areas with significant environmental contamination and poor health infrastructure precluding appropriate follow-up and preventing access to medical care. Toxoplasmosis is a significant public health challenge in Morocco, with a relatively heavy burden of infection and, to this point, minimal investment nationally to address this infection. Herein, we analyse the performance of a novel, low-cost rapid test using fingerstick-derived whole blood from 632 women (82 of whom were pregnant) from slums, educational centres, and from nomad groups across different geographical regions (i.e. oceanic, mountainous) of Morocco. The POC test was highly sensitive and specific from all settings. In the first group of 283 women, sera were tested by Platelia ELISA IgG and IgM along with fingerstick whole blood test. Then a matrix study with 349 women was performed in which fingerstick – POC test results and serum obtained by venipuncture contemporaneously were compared. These results show high POC test performance (Sensitivity: 96.4% [IC95 90.6–98.9%]; Specificity: 99.6% [IC95 97.3–99.9%]) and high prevalence of Toxoplasma infection among women living in rural and mountainous areas, and in urban areas with lower educational levels. The high performance of POC test confirms that it can reduce the need for venipuncture and clinical infrastructure in a low-resource setting. It can be used to efficiently perform seroprevalence determinations in large group settings across a range of demographics, and potentially expands healthcare access, thereby preventing human suffering.

Contribution of the Toxoplasma ICT IgG IgM® test in determining the immune status of pregnant women against toxoplasmosis

BACKGROUND

An immunochromatography technology (ICT) rapid diagnostic test, the Toxoplasma ICT IgG-IgM® , was recently developed. Our aim was to study its contribution to establish accurately the Toxoplasma immune status in Tunisian pregnant women using Western blot (WB) Toxo II IgG® as a reference technique.

METHODS

Thirty-nine sera were selected for the study from among 2,615 which were already tested by IgG and IgM ELISA. They displayed equivocal IgG titres (4.4-9 IU/ml) in absence of IgM (19 sera) or IgM anti-Toxoplasma antibodies in absence of IgG (titre <4.4 IU/ml) (20 sera). All these sera were additionally tested by WB Toxo II IgG® .

RESULTS

Immunochromatography technology Sensitivity in the detection either of low IgG titres in absence of IgM or of specific anti-Toxoplasma IgM was 100%. Only one serum with equivocal IgG titre by ELISA and negative with Toxo II IgG® test revealed positive in ICT. However, this serum showed a P30 band in WB analysis. On the other hand, three sera positive in ELISA IgM and negative in ELISA IgG revealed positive in ICT and negative in WB Toxo II IgG® , the reference test.

CONCLUSION

Results confirm the high sensitivity of Toxoplasma ICT IgG-IgM® in detecting both specific anti-Toxoplasma IgG and IgM, and highlight the usefulness of this rapid test as a first or second-line Toxoplasma serological test in pregnant women.

Foodborne transmission of Toxoplasma gondii infection in the last decade. An overview

Toxoplasmosis is a zoonotic disease of global distribution and importance. It is caused by the protozoan parasite Toxoplasma gondii, the only species in the Toxoplasma genus. This parasite can infect most warm-blooded animals, including humans and livestock. Main routes of transmission are by ingestion of tissue cysts in raw or undercooked meat of infected animals, ingestion of raw vegetables or water contaminated with T. gondii oocysts from cat feces, and transplacental. Around one-third of human beings are chronically infected with T. gondii. Most infections appear to be asymptomatic in immunocompetent persons, but toxoplasmosis can be fatal to the fetus and immunocompromised adults. Water and foodborne outbreaks have been caused by this parasite worldwide, but few are well documented. Importantly, T. gondii is a parasite of high importance in animal health, causing reproductive failure, particularly in small ruminants, and clinical toxoplasmosis in many species. This overview discusses the knowledge of T. gondii infections in the last decade focusing on the foodborne transmission of this parasite.

Toxoplasmosis in pregnancy: a neglected bane but a serious threat in Nigeria

Toxoplasmosis is a global health threat in which occurrence in pregnant women poses grave consequences to fetal wellbeing. Studies on prenatal Toxoplasma gondii infection are generally limited in sub-Saharan African countries, including Nigeria. The risk of transmission of toxoplasmosis is very high in Nigeria due to the favourable climatic conditions and prevailing behavioural and socio-economic factors that could aid transmission. Currently, there are no systematic and organized procedures for diagnosis and treatment of maternal toxoplasmosis in Nigeria. These conditions forecast possible unabated transmission in many areas and exponential impact on associated adverse events of the disease during pregnancy. This paper highlights the importance of early diagnosis and treatment during pregnancy which may forestall subsequent development of infection in children delivered by infected mothers. Inclusion of toxoplasmosis control policy in the routine antenatal care of pregnant women is therefore strongly recommended.

Prevention and mitigation of congenital toxoplasmosis. Economic costs and benefits in diverse settings

Congenital toxoplasmosis (CT), the result of a primary infection of pregnant women with Toxoplasma gondii which was transmitted to the fetus, may result in mild to deep injuries occurring in the newborn or later in its development or in adolescence. The visual and cognitive impairment that can result imposes substantial economic costs on the individual and society. Numerous observational studies favor the conclusion that, with preventive measures currently available, it is possible to reduce the incidence of infections in pregnant women, the incidence of fetal infection by preventing transplacental transmission, and the gravity of injury in infected newborns. Treatment of infected newborns can also reduce the severity of consequences and the frequency of their occurrence later in life. Prevention programs, however, are applied in only a few countries; in most countries implementation of a national prevention program has not been considered or has been thought to be too expensive. This article lists the methods of prevention of CT and describes existing national prevention programs in France and Austria. It analyzes the economic costs and benefits of maternal screening for CT prevention and mitigation for society and for health systems. The economic feasibility of implementing national screening in low-prevalence, high-cost countries is illustrated with the example of the United States. New diagnostic tools are discussed and the implication of lower costs is considered, for countries with well-established screening programs as well as those with inadequate prenatal care networks.

Serological and molecular rapid diagnostic tests for Toxoplasma infection in humans and animals

Infection by Toxoplasma gondii is prevalent worldwide. The parasite can infect a broad spectrum of vertebrate hosts, but infection of fetuses and immunocompromised patients is of particular concern. Easy-to-perform, robust, and highly sensitive and specific methods to detect Toxoplasma infection are important for the treatment and management of patients. Rapid diagnostic methods that do not sacrifice the accuracy of the assay and give reproducible results in a short time are highly desirable. In this context, rapid diagnostic tests (RDTs), especially with point-of-care (POC) features, are promising diagnostic methods in clinical microbiology laboratories, especially in areas with minimal laboratory facilities. More advanced methods using microfluidics and sensor technology will be the future trend. In this review, we discuss serological and molecular-based rapid diagnostic tests for detecting Toxoplasma infection in humans as well as animals.

Validity of a new immunochromatographic test in detection of Toxoplasma gondii in cancer patients

Screening of toxoplasmosis in cancer patients is mandatory especially before starting treatment to guard against life-threatening disseminated disease. Diagnosis of toxoplasmosis rely mainly on serology. The most widely used method for detection of anti-Toxoplasma gondii (T. gondii) antibodies is the enzyme linked immunosorbent assay (ELISA), being available and reliable. Immunochromatographic tests (ICT) attracted a lot of attention recently being one of the high quality, rapid and easy to perform tests. Available data comparing the performance of ICT versus ELISA techniques have yielded inconsistent results and none compared their performance among the immunocompromised cancer patients. Therefore, we designed this study to compare the performance of a new ICT (the OnSite Toxo IgG/IgM Combo Rapid test) and ELISA techniques for the detection of anti-T. gondii antibody as a tool for screening for toxoplasmosis among cancer patients in Cairo-Egypt. Among 180 cancer patients, a total of 110 patients (61.1%) were positive for anti-T. gondii antibodies by one or both methods. Agreement between both methods was found in 78.8% of the samples. By using ELISA technique as a gold standard test for the detection of anti-T. gondii antibodies, our results showed 87.5% specificity and 74% sensitivity of ICT technique. Moreover, our results proved that ICT is more sensitive in detecting lower level of antibodies than ELISA, that makes it preferable as a screening test for the immunocompromised patients.

Evaluation of Three Point-of-Care Tests for Detection of Toxoplasma Immunoglobulin IgG and IgM in the United States: Proof of Concept and Challenges

Background

The cost of conventional serological testing for toxoplasmosis discourages universal adoption of prenatal monthly screening programs to prevent congenital toxoplasmosis. Point-of-care (POC) technology may constitute a cost-effective approach.

Methods

We evaluated the diagnostic accuracy of 3 Toxoplasma POC tests against gold-standard testing performed at Palo Alto Medical Foundation Toxoplasma Serology Laboratory (PAMF-TSL). The POC tests included the following: Toxo IgG/IgM Rapid Test (Biopanda) and the OnSite Toxo IgG/IgM Combo-Rapid-test that detect IgG and IgM separately, and the Toxoplasma ICT-IgG-IgM-bk (LDBIO) that detects either or both immunoglobulin IgG/IgM in combination. Samples were selected from PAMF-TSL biobank (n = 210) and Centers for Disease Control and Prevention Toxoplasma 1998 Human Serum Panel (n = 100). Based on PAMF-TSL testing, Toxoplasma-infection status was classified in 4 categories: acute infections (n = 85), chronic infections (n = 85), false-positive Toxoplasma IgM (n = 60), and seronegative (n = 80). The POC testing was performed in duplicate following manufacturer's instructions by investigators blinded to PAMF-TSL results. Sensitivity and specificity were calculated.

Results

A total of 1860 POC tests were performed. For detection of Toxoplasma IgG, sensitivity was 100% (170 of 170; 95% confidence interval [CI], 97.8%-100%) for all 3 POC kits; specificity was also comparable at 96.3% (77 of 80; 95% CI, 89.5%-98.9%), 97.5% (78 of 80; 95% CI, 91.3%-99.6%), and 98.8% (79 of 80; 95% CI, 93.2%-99.9%). However, sensitivity for detection of Toxoplasma IgM varied significantly across POC tests: Biopanda, 62.2% (51 of 82; 95% CI, 51.4%-71.9%); OnSite, 28% (23 of 82; 95% CI, 19.5%-38.6%); and LDBIO combined IgG/IgM, 100% (82 of 82; 95% CI, 95.5%-100%). Diagnostic accuracy was significantly higher for the LDBIO POC kit. The POC kits did not exhibit cross-reactivity for false-positive Toxoplasma-IgM sera.

Conclusions

The 3 evaluated POC kits revealed optimal sensitivity for Toxoplasma-IgG antibodies. The LDBIO-POC test exhibited 100% sensitivity for the combined detection of IgG/IgM in acute and chronic Toxoplasma infection. Biopanda and Onsite POC tests exhibited poor sensitivity for Toxoplasma-IgM detection.

Global initiative for congenital toxoplasmosis: an observational and international comparative clinical analysis

Globally, congenital toxoplasmosis remains a significant cause of morbidity and mortality, and outbreaks of infection with T. gondii represent a significant, emerging public health burden, especially in the developing world. This parasite is a threat to public health. Disease often is not recognized and is inadequately managed. Herein, we analyze the status of congenital toxoplasmosis in Morocco, Colombia, the United States, and France. We identify the unique challenges faced by each nation in the implementation of optimal approaches to congenital toxoplasmosis as a public health problem. We suggest that developed and developing countries use a multipronged approach, modeling their public health management protocols after those in France. We conclude that education, screening, appropriate treatment, and the development of novel modalities will be required to intervene successfully in caring for individuals with this infection. Gestational screening has been demonstrated to be cost-effective, morbidity-sparing, and life-saving. Recognition of the value and promise of public health interventions to prevent human suffering from this emerging infection will facilitate better patient and societal outcomes.

Rapid diagnosis of parasitic diseases: current scenario and future needs

BACKGROUND

Parasitic diseases are one of the world's most devastating and prevalent infections, causing millions of morbidities and mortalities annually. In the past, many of these infections have been linked predominantly to tropical or subtropical areas. Nowadays, however, climatic and vector ecology changes, a significant increase in international travel, armed conflicts, and migration of humans and animals have influenced the transmission of some parasitic diseases from 'book pages' to reality in developed countries. It has also been noted that many patients who have never travelled to endemic areas suffer from blood-borne infections caused by protozoa. In the light of existing knowledge, this new trend can be explained by the fact that in the process of migration a large number of asymptomatic carriers become a part of the blood bank donor and transplant donor populations. Accurate and rapid diagnosis represents the crucial weapon in the fight against parasitic infections.

AIMS

To review old and new approaches for rapid diagnosis of parasitic infections.

SOURCES

Data for this review were obtained through searches of PubMed using combinations of the following terms: parasitological diagnostics, microscopy, lateral flow assays, immunochromatographic assays, multiplex-PCR, and transplantation.

CONTENT

In this review, we provide a brief account of the advantages and limitations of rapid methods for diagnosis of parasitic diseases and focus our attention on current and future research in this area. The approximate costs associated with the use of different techniques and their applicability in endemic and non-endemic areas are also discussed.

IMPLICATIONS

Microscopy remains the cornerstone of parasitological diagnostics, especially in the field and low-resource settings, and provides epidemiological assessment of parasite burden. However, increased use and availability of point-of-care tests and molecular assays in modern era allow more rapid and accurate diagnoses and increased sensitivity in the identification of parasitic infections.

Congenital Toxoplasmosis: A Plea for a Neglected Disease

Maternal infection by Toxoplasma gondii during pregnancy may have serious consequences for the fetus, ranging from miscarriage, central nervous system involvement, retinochoroiditis, or subclinical infection at birth with a risk of late onset of ocular diseases. As infection in pregnant women is usually symptomless, the diagnosis relies only on serological tests. Some countries like France and Austria have organized a regular serological testing of pregnant women, some others have no prenatal program of surveillance. Reasons for these discrepant attitudes are many and debatable. Among them are the efficacy of antenatal treatment and cost-effectiveness of such a program. A significant body of data demonstrated that rapid onset of treatment after maternal infection reduces the risk and severity of fetal infection. Recent cost-effectiveness studies support regular screening. This lack of consensus put both pregnant women and care providers in a difficult situation. Another reason why congenital toxoplasmosis is disregarded in some countries is the lack of precise information about its impact on the population. Precise estimations on the burden of the disease can be achieved by systematic screening that will avoid bias or underreporting of cases and provide a clear view of its outcome.

Evaluation of a New Immunochromatography Technology Test (LDBio Diagnostics) To Detect Toxoplasma IgG and IgM: Comparison with the Routine Architect Technique

A study comparing the ICT (immunochromatography technology) Toxoplasma IgG and IgM rapid diagnostic test (LDBio Diagnostics, France) with a fully automated system, Architect, was performed on samples from university hospitals of Marseille and Saint-Etienne. A total of 767 prospective sera and 235 selected sera were collected. The panels were selected to test various IgG and IgM parameters. The reference technique, Toxoplasma IgGII Western blot analysis (LDBio Diagnostics), was used to confirm the IgG results, and commercial kits Platelia Toxo IgM (Bio-Rad) and Toxo-ISAgA (bioMérieux) were used in Saint-Etienne and Marseille, respectively, as the IgM reference techniques. Sensitivity and specificity of the ICT and the Architect IgG assays were compared using a prospective panel. Sensitivity was 100% for the ICT test and 92.1% for Architect (cutoff at 1.6 IU/ml). The low-IgG-titer serum results confirmed that ICT sensitivity was superior to that of Architect. Specificity was 98.7% (ICT) and 99.8% (Architect IgG). The ICT test is also useful for detecting IgM without IgG and is both sensitive (100%) and specific (100%), as it can distinguish nonspecific IgM from specific Toxoplasma IgM. In comparison, IgM sensitivity and specificity on Architect are 96.1% and 99.6%, respectively (cutoff at 0.5 arbitrary units [AU]/ml). To conclude, this new test overcomes the limitations of automated screening techniques, which are not sensitive enough for IgG and lack specificity for IgM (rare IgM false-positive cases).

Point-of-care testing for Toxoplasma gondii IgG/IgM using Toxoplasma ICT IgG-IgM test with sera from the United States and implications for developing countries

Background

Congenital toxoplasmosis is a serious but preventable and treatable disease. Gestational screening facilitates early detection and treatment of primary acquisition. Thus, fetal infection can be promptly diagnosed and treated and outcomes can be improved.

Methods

We tested 180 sera with the Toxoplasma ICT IgG-IgM point-of-care (POC) test. Sera were from 116 chronically infected persons (48 serotype II; 14 serotype I-III; 25 serotype I-IIIa; 28 serotype Atypical, haplogroup 12; 1 not typed). These represent strains of parasites infecting mothers of congenitally infected children in the U.S. 51 seronegative samples and 13 samples from recently infected persons known to be IgG/IgM positive within the prior 2.7 months also were tested. Interpretation was confirmed by two blinded observers. A comparison of costs for POC vs. commercial laboratory testing methods was performed.

Results

We found that this new Toxoplasma ICT IgG-IgM POC test was highly sensitive (100%) and specific (100%) for distinguishing IgG/IgM-positive from negative sera. Use of such reliable POC tests can be cost-saving and benefit patients.

Conclusions

Our work demonstrates that the Toxoplasma ICT IgG-IgM test can function reliably as a point-of-care test to diagnose Toxoplasma gondii infection in the U.S. This provides an opportunity to improve maternal-fetal care by using approaches, diagnostic tools, and medicines already available. This infection has serious, lifelong consequences for infected persons and their families. From the present study, it appears a simple, low-cost POC test is now available to help prevent morbidity/disability, decrease cost, and make gestational screening feasible. It also offers new options for improved prenatal care in low- and middle-income countries.

Toxoplasmosis, a disease caused by the parasite Toxoplasma gondii, presents a major health burden in both the developed and developing world. Untreated congenital toxoplasmosis causes damage to the eye and brain, but early detection and treatment reduce transmission and disease. Fetal infection can be promptly diagnosed and treated and outcomes can be improved. Gestational screening for toxoplasmosis has international precedent. In this paper, we demonstrated that the new Toxoplasma ICT IgG-IgM test had 100% sensitivity and specificity in detecting Toxoplasma infection (N = 180 U.S. sera from uninfected persons and those with varying parasite serotypes). The use of an inexpensive, easy-to-use point-of-care test facilitates screening of pregnant women for T. gondii infection. In turn, this facilitates prompt treatment for the infection and thereby reduces the health burden caused by this disease. This provides an opportunity to improve maternal-fetal care by using approaches, diagnostic tools, and medicines already available.