Acute Toxoplasma Infection Research Articles

Enzymatically enhanced ultrastructure expansion microscopy unlocks expansion of in vitro Toxoplasma gondii cysts.

Toxoplasma gondii is an intracellular parasite capable of establishing long-term chronic infection in nearly all warm-blooded animals. During the chronic stage, parasites encapsulate to form cysts predominantly in neurons and skeletal muscle. Current anti-Toxoplasma drugs do not eradicate chronic parasites, leaving a reservoir of infection. The cyst is critical for disease transmission and pathology, yet it is harder to study, with the function of many chronic-stage proteins still unknown. Ultrastructure expansion microscopy, a new method to overcome the light microscopy's diffraction limit by physically expanding the sample, allowed in-depth studies of acute Toxoplasma infection. We show that Toxoplasma cysts resist expansion using standard protocol, but an additional enzymatic digestion with the mucinase StcE allows full expansion. This protocol offers new avenues for examining the chronic stage, including precise spatial organization of cyst-specific proteins, linking these locations to morphological structures, and detailed investigations of components of the durable cyst wall.

Interleukins IL33/ST2 and IL1-β in Intrauterine Growth Restriction and Seropositivity of Anti-Toxoplasma gondii Antibodies.

Toxoplasma gondii (T. gondii) is the causal agent of toxoplasmosis. It may produce severe damage in immunocompromised individuals, as well as congenital infection and intrauterine growth restriction (IUGR). Previous reports have associated interleukin IL-33 with miscarriage, fetal damage, and premature delivery due to infections with various microorganisms. However, IL-33 has not been associated with congenital toxoplasmosis. The sST2 receptor has been reported in patients who have had recurrent miscarriages. On the other hand, IL-1β was not found in acute Toxoplasma infection. Our aim was to analyze the associations between the serum levels of IL-33 and IL-1β in IUGR and toxoplasmosis during pregnancy. Eighty-four serum samples from pregnant women who had undergone 26 weeks of gestation were grouped as follows: with anti-Toxoplasma antibodies, without anti-Toxoplasma antibodies, IUGR, and the control group. IgG and IgM anti-T. gondii antibodies, as well as IL-33, ST2, and IL-1β, were determined using an ELISA assay. Statistical analyses were performed using the Pearson and Chi-square correlation coefficients, as well as the risk factors and Odds Ratios (ORs), with a confidence interval of 95% (CI 95). The results showed that 15/84 (17.8%) of cases were positive for IgG anti-Toxoplasma antibodies and 2/84 (2.38%) of cases were positive for IgM. A statistically significant difference was found between IUGR and IL-33 (p < 0.001), as well as between ST2 and IUGR (p < 0.001). In conclusion, IUGR was significantly associated with IL-33 and ST2 positivity based on the overall IUGR grade. No significant association was found between IUGR and the presence of anti-Toxoplasma antibodies. There was no association between IL-1β and IUGR. More research is needed to strengthen the utility of IL-33 and ST2 as biomarkers of IUGR.

A public health problem in pregnant women: acute toxoplasma infection - a retrospective study of 12 years of data from a training and research hospital in Izmir

Introduction: The aim of this study is to identify the prevalence of acute toxoplasmosis in pregnant patients who are monitored in our hospital and to provide insight into screening and management options by assessing maternal and fetal outcomes. Methods: Pregnants between the ages of 18-49, who were followed up in the Gynecology and Obstetrics Polyclinic/Clinic and Infectious Diseases Polyclinic/Clinic of a Training and Research Hospital between January 1, 2010 and December 31, 2021, were included in this study. T. gondii IgM, IgG and avidity tests which were performed for pregnant women were evaluated retrospectively. Results: The study consisted of 7480 pregnants. Three hundred eighty-six (%5.16) of the pregnant women tested positive. Anti-T. gondii IgM seropositivity was found to be most common in the 18-28 age group (7.82%), and this frequency gradually decreased as age progressed. Two of the 122 patients whose polymerase chain reaction for T. gondii was examined from amniotic fluid at the outer center had congenital toxoplasmosis, and these pregnancies were terminated. Conclusions: Pregnant women continue to have a considerable risk of developing acute toxoplasmosis. For this infestation, which still remains on the agenda as a public health problem, every individual who is planning a pregnancy and has not had a serological test before should be screened before pregnancy. Pregnant women should continue to be informed and educated about this parasite, in our opinion.

CD4+ T Cell Responses to Toxoplasma gondii Are a Double-Edged Sword.

CD4+ T cells have been found to play critical roles in the control of both acute and chronic Toxoplasma infection. Previous studies identified a protective role for the Toxoplasma CD4+ T cell-eliciting peptide AS15 (AVEIHRPVPGTAPPS) in C57BL/6J mice. Herein, we found that immunizing mice with AS15 combined with GLA-SE, a TLR-4 agonist in emulsion adjuvant, can be either helpful in protecting male and female mice at early stages against Type I and Type II Toxoplasma parasites or harmful (lethal with intestinal, hepatic, and spleen pathology associated with a storm of IL6). Introducing the universal CD4+ T cell epitope PADRE abrogates the harmful phenotype of AS15. Our findings demonstrate quantitative and qualitative features of an effective Toxoplasma-specific CD4+ T cell response that should be considered in testing next-generation vaccines against toxoplasmosis. Our results also are cautionary that individual vaccine constituents can cause severe harm depending on the company they keep.

Toxoplasmosis Screening during Pregnancy in a Romanian Infectious Diseases Tertiary Center: Results of a 15 Years Follow-Up Program.

Maternal infection with Toxoplasma gondii during pregnancy may have serious consequences for the fetus. In Romania, screening for toxoplasmosis is included in the first antenatal visit. A retrospective study was performed on all toxoplasmosis antenatal screening patients between May 2008 and February 2023. Twenty-seven thousand one hundred sixty-nine (27,169) pregnant women presented for prenatal screening once (22,858) or several times: during the same pregnancy (209) or during multiple pregnancies (4102). Thirty-one thousand six hundred fifty-eight (31,658) tests for IgM and IgG antibodies were performed. Nine thousand eighty-three (9083) tests (28.69%), corresponding to 7911 women (29.12%), were positive for IgG antibodies. The seroprevalence increased with patients' age, decreased in time intervals, and was more frequently associated with rural residence. At risk for acquiring the infection during the pregnancy were women with negative anti-Toxoplasma IgG antibodies (70.88%), but only 0.9% of them presented for rescreening during the same pregnancy. Acute Toxoplasma infection (ATI) was suspected in 44 patients (0.16%) due to IgG seroconversion and/or low or borderline IgG avidity. A questionnaire follow-up interview was performed, and no congenital toxoplasmosis was identified in children born from mothers with probable ATI. Our study demonstrates poor compliance with the screening program in the Romanian population.

Clinical Spectrum, Radiological Findings, and Outcomes of Severe Toxoplasmosis in Immunocompetent Hosts: A Systematic Review.

Accumulating evidence suggests that toxoplasmosis in immunocompetent hosts can be severe and life-threatening. We performed a systematic review of severe toxoplasmosis cases in immunocompetent patients to gain insight into the epidemiology, clinical characteristics, radiological findings, and outcomes of these cases. We classified severe toxoplasmosis as cases with the symptomatic involvement of target organs (the lungs, central nervous system (CNS), and heart), disseminated disease, prolonged disease (>3 months), or a fatal outcome. Our primary analysis focused on cases published from 1985-2022 to avoid confounding with cases in AIDS patients. We identified 82 pertinent articles (1985-2022) with a total of 117 eligible cases; the top five countries for these cases were French Guiana (20%), France (15%), Colombia (9%), India (9%), and Brazil (7%). Overall, 44% (51/117) of cases had pulmonary involvement, 39% (46/117) CNS, 31% (36/117) cardiac, 24% (28/117) disseminated disease, 2% (2/117) had prolonged disease, and 8% (9/117) of patients died. More than one organ was involved in 26% (31/117) of cases. Eighty-four percent (98/117) of cases occurred in the context of a recent acute primary Toxoplasma infection; for the remaining, the exact timing of infection was unclear. Genotyping data were very sparse. Among those reporting genotyping data, 96% (22/23) were caused by atypical non-type II strains; one case was caused by a type-II strain. Only half of the cases reported risk factors. The most common risk factors were eating raw/undercooked meat or eating game meat (47% (28/60)), drinking untreated water (37% (22/60)), or living in a toxoplasmosis high-prevalence area (38% (23/60)). For the 51 pulmonary cases, the main clinical presentation was pneumonia or pleural effusions in 94% (48/51) and respiratory failure in 47% (24/51). For the 46 CNS cases, the main clinical presentation was encephalitis in 54% (25/46), meningitis in 13% (6/46), focal neurologic findings in 24% (11/46), cranial nerve palsies in 17% (8/46), Guillain-Barre syndrome or Miller Fisher syndrome in 7% (3/46), and Brown-Sequard syndrome in 2% (1/46) of cases; more than one clinical manifestation could also be present. Among the 41 CNS cases reporting the CNS imaging findings, 68% (28/41) had focal supratentorial lesions and 7% (3/41) had focal infratentorial lesions. Brain abscess-like/mass-like lesions were seen in 51% (21/41) of cases. For the 36 cardiac cases, the main clinical presentation was myocarditis in 75% (27/36), pericarditis in 50% (18/36), heart failure and/or cardiogenic shock in 19% (7/36), and cardiac arrhythmias in 22% (8/36); more than one manifestation could also be present. Illness was critical in 49% (44/90) of cases intensive care unit care was needed in 54% (29/54) of cases among those reporting this information, and 9 patients died. The diagnosis of severe toxoplasmosis in immunocompetent hosts can be challenging. Toxoplasmosis should be considered in the differential diagnosis of immunocompetent patients presenting with severe illness of unclear etiology with pulmonary, cardiac, CNS, or multiorgan involvement/failure, or prolonged febrile illness, even in the absence of common exposure risk factors or common manifestations of toxoplasmosis (e.g., fever, mononucleosis-like illness, lymphadenopathy, and chorioretinitis). Fatal outcomes can also rarely occur in immunocompetent patients. Prompt initiation of anti-Toxoplasma treatment can be lifesaving.

Toxoplasmosis: A Timeless Challenge for Pregnancy

This study aimed to evaluate the prevalence of toxoplasmosis in pregnant women, as well as the general characteristics, clinical and laboratory findings, and pregnancy and fetal outcomes of pregnant women diagnosed with acute toxoplasma infection (ATI). The toxoplasma IgM, IgG, and IgG avidity test results of pregnant women who applied to our referral hospital between January 2016 and June 2022, and among them, those diagnosed with ATI, were analyzed. The 119 patients diagnosed with ATI during this time period were included for further analysis. The prevalence of toxoplasmosis in pregnant women was found to be 46.2%, and the rate of ATI was 4%. The total mother-to-child transmission rate was 5% (5/101). Congenital toxoplasmosis (CT) was observed in 1 (1.1%) child of the 87 pregnant women who received spiramycin prophylaxis, though it was found in 4 (30.8%) of the children of the 13 untreated mothers. With respect to prenatal treatment, CT rates were significantly higher in the children born to untreated mothers (p = 0.001). In conclusion, although toxoplasma seroprevalence was found to be high in our region, there was a paucity in diagnosis, follow-up, and treatment. Our findings support that prenatal spiramycin prophylaxis is effective in preventing the transmission of parasites from mother to child.

Protective immunity induced with a DNA vaccine encoding B- and T-cells multi-epitope SAG1, ROP16, MIC4, GRA12, M2AP, and multi-epitope ROP8 against acute and chronic toxoplasmosis in BALB/c mice

BackgroundT. gondii infection is characterized by a high global prevalence. Nearly, 16–40% of people have been infected by T. gondii. Although T. gondii often causes subclinical infection, it may cause severe complications in newborns with congenital infection and immunocompromised individuals. Constant attempts of scientists have made valuable findings in the development of T. gondii candidate vaccines. However, an effective vaccine has not been successfully developed yet. In this study, multi-epitope SAG1, MIC4, ROP16, M2AP, GRA12, and multi-epitope ROP8 were injected into BALB/c mice intramuscularly, as cocktailed plasmids or as single-gene plasmids to assess the immune response against chronic and acute Toxoplasma infection. MethodsBALB/c mice were immunized on days 0, 21, and 42. The immune responses of both vaccinated and control groups were evaluated using cytokine and antibody measurements, lymphocyte proliferation assay, survival time, and average number of cysts in each brain. ResultsThe results indicated that DNA vaccination using multi-epitope ROP8 and multi-epitope SAG1, ROP16, MIC4, GRA12, M2AP could elicit both cellular and humoral immune responses, and enhanced the survival time in BALB/c mice. Also, the administration of multi-epitope ROP8 plus multi-epitope SAG1, ROP16, MIC4, GRA12, M2AP could enhance the concentrations of IgG antibody, elicit a mixed IgG1/IgG2a reaction with the predominance of the IgG2a, increase the release of IFN-γ cytokine, prolonge the survival time, and reduce the brain cysts. ConclusionsHere, we report that vaccination using cocktailed plasmids could induce better protective immunity compared to single plasmid for acute and chronic T. gondii infection.

Investigation of Toxoplasma infection in zoo animals using multispecies ELISA and GRA7 nested PCR

BackgroundToxoplasma is an obligate intracellular protozoan that causes an important zoonotic disease with a worldwide distribution. Felids are the definitive hosts of this parasite, while virtually all warm-blooded animals, including birds, serve as intermediate hosts. Four ring-tailed lemurs (Lemur catta) in the Taipei Zoo died of acute Toxoplasma infection in June 2019. Since then, Toxoplasma has occasionally been identified in this Zoo during necropsy of dead animals and PCR of animal blood samples. Therefore, a general survey of Toxoplasma infection in animals in the Zoo seems to be needed.Methods and resultsAn indirect multispecies ELISA was used for the first time to screen for Toxoplasma infection in 326 serum samples collected from 75 species of animals. The infection rate of Toxoplasma was 27% (88/326). A commercial latex agglutination (LAT) assay was used to re-examine the samples with doubtful and uncertain ELISA results (151 samples from 42 species). The infection rate increased to 36.2% (118/326), and the indirect multispecies ELISA appeared to be applicable to 31 of 75 species animals included in this study. Nested PCR assays targeting the dense granule protein 7 (GRA7) gene and B1 gene were also used to detect Toxoplasma in DNA samples extracted from 10 liver or blood specimens from 8 animals. GRA7 gene fragments were amplified from 8 samples from 7 animals, while B1 gene fragments were amplified from only 4 samples from 4 animals. From the B1 nested PCR and the sequence data of GRA7 fragments amplified from infectious specimens, the animals in the Zoo were speculated to have been infected by at least three different Toxoplasma variants.ConclusionsAccording to the serological investigation, we speculated that over one-third (36.2%) of animals in Taipei Zoo presented the infection of Toxoplasma, and the indirect multispecies ELISA we used can be applied to detect Toxoplasma infection in 31 animal species included in this study. Sequence analysis revealed that at least three Toxoplasma variants were infecting the animals of Taipei Zoo.

Multisystem Inflammatory Syndrome in Adults and Severe Toxoplasmosis: Similar Clinical Presentations, Potentially Severe Outcomes.

We report a case of a 21-year-old previously healthy man who developed severe toxoplasmosis with chorioretinitis and myositis 2 months after receiving corticosteroids for presumed multisystem inflammatory syndrome in adults, in the setting of a recently acquired acute Toxoplasma infection, likely during a trip to Latin America.

A Histone Deacetylase (HDAC) Inhibitor with Pleiotropic In Vitro Anti-Toxoplasma and Anti-Plasmodium Activities Controls Acute and Chronic Toxoplasma Infection in Mice.

Toxoplasmosis is a highly prevalent human disease, and virulent strains of this parasite emerge from wild biotopes. Here, we report on the potential of a histone deacetylase (HDAC) inhibitor we previously synthesized, named JF363, to act in vitro against a large panel of Toxoplasma strains, as well as against the liver and blood stages of Plasmodium parasites, the causative agents of malaria. In vivo administration of the drug significantly increases the survival of mice during the acute phase of infection by T. gondii, thus delaying its spreading. We further provide evidence of the compound’s efficiency in controlling the formation of cysts in the brain of T. gondii-infected mice. A convincing docking of the JF363 compound in the active site of the five annotated ME49 T. gondii HDACs was performed by extensive sequence–structure comparison modeling. The resulting complexes show a similar mode of binding in the five paralogous structures and a quite similar prediction of affinities in the micromolar range. Altogether, these results pave the way for further development of this compound to treat acute and chronic toxoplasmosis. It also shows promise for the future development of anti-Plasmodium therapeutic interventions.

Investigating the risk factors for seroprevalence and the correlation between CD4+ T-cell count and humoral antibody responses to Toxoplasma gondii infection amongst HIV patients in the Bamenda Health District, Cameroon.

Toxoplasmosis is caused by an obligate intracellular tissue protozoan parasite, Toxoplasma gondii that infect humans and other warm-blooded animals. Transmission to humans is by eating raw or inadequately cooked infected meat or through ingestion of oocysts that cats have passed in faeces. Studies have shown life-threatening and substantial neurologic damage in immunocompromised patients; however, 80% of humans remain asymptomatic. The aim of this study was to determine the seroprevalence of Toxoplasma gondii infection in HIV positive patients and the risk factors associated with the infection, and to investigate the correlation between CD4+ T-cell count and toxoplasma specific antibodies as possible predictors of each other amongst HIV patients in the Bamenda Health District of the North West Region of Cameroon. A cross-sectional study was conducted, in which 325 HIV patients were recruited for administration of questionnaire, serological diagnosis of T. gondii and measurement of CD4+ T-cell count. Bivariate and multivariate logistic regression was used to identify risk factors associated with T. gondii infection while the linear regression was used to investigate the relationship between CD4+ T-cell count and antibody levels against T. gondii. The findings showed that, majority (45.8%) of HIV patients suffered from chronic (IgG antibody) infection, and 6.5% from acute (IgM and IgM/IgG antibody) toxoplasma infection. The overall sero-prevalence of T. gondii infection amongst HIV patients was 50.5%. On the whole, 43 men (45.7%) and 127 women (55%) presented with anti- T. gondii antibodies; however, there was no significant difference amongst males and females who were positive to T. gondii infection (p = 0.131). Marital status (p = 0.0003), contact with garden soil (p = 0.0062), and garden ownership (p = 0.009), were factors that showed significant association with T. gondii infection. There was no significant difference (p = 0.909) between the mean CD4+ T-cell count of HIV patients negative for toxoplasma infection (502.7 cells/mL), chronically infected with T. gondii (517.7 cells/mL) and acutely infected with T. gondii (513.1 cells/mL). CD4+ T-cell count was neither a predictor of IgM antibody titer (r = 0.193, p = 0.401), nor IgG antibody titer (r = 0.149, p = 0.519) amongst HIV patients acutely infected with T. gondii. The findings from this study underscore the need to implement preventive and control measures to fight against T. gondii infection amongst HIV patients in the Bamenda Health District.

Synthesis and evaluation of mycophenolic acid derivatives as potential anti-Toxoplasma gondii agents

Nineteen mycophenolic acid (MPA) derivatives were designed and synthesized, and their anti-Toxoplasma activity evaluated for the first time. Among them, N-propylimidazole-modified compound E5 demonstrated the strongest activity, and the IC50 against HFF-1 (Human Foreskin Fibroblasts-1) cells following infection with T. gondii is 80.9 μM (MPA-211.5 μM) and its selectivity index is 2.2 (MPA-1.2). In vivo experiments, E5 can significantly inhibit the proliferation of tachyzoites in the abdominal cavity of mice acutely infected with T. gondii (inhibition rates 46.7%), and this inhibitory effect was greater than that of spiramycin (inhibition rates 31.3%) and MPA (inhibition rates 15.9%), this indicated that E5 had significant protective effects on the host during acute Toxoplasma infection. In addition, E5 can reduce the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the serum of infected mice, significantly increase the level of glutathione (GSH) in the liver, and significantly reduce the level of malondialdehyde (MDA), indicating that it has a hepatoprotective effect against T. gondii infection. Similarly, E5 can relieve hepatomegaly and splenomegaly induced by acute Toxoplasma infection. Spiramycin aggravated appetite loss in infected mice, while E5 did not. In summary, the results indicated that E5 has potential as a candidate anti-T. gondii drug.

Cannabinoid receptors and the proconvulsant effect of toxoplasmosis in mice

Toxoplasmosis is an infectious disease caused by the intracellular parasite Toxoplasma gondii that harms the brain and increases the risk of epilepsy acquisition. It is well known that cannabinoid (CB) signaling is activated following brain insults and protects the neurons from excitotoxicity and inflammation. We examined the role of CB neurotransmission in the proconvulsant effect of Toxoplasmosis in mice.Toxoplasmosis was established in mice by intraperitoneal injection of T. gondii cysts. The mice with acute and/or chronic Toxoplasma infection were pretreated (through intracerebroventricular injection) with CB1 and CB2 receptor agonists (ACEA and HU308) and antagonists (AM251 and AM630), as well as JZL184 (the irreversible inhibitor of mono acyl glycerol lipase, enzyme degrading the endogenous cannabinoid 2-Acyl glycerol). The seizure threshold was then measured by tail vein infusion of pentylenetetrazole.In healthy uninfected mice JZL184, ACEA, and AM630 increased the seizure threshold in a dose-dependent manner, whereas AM251 and HU308 showed dose-dependent proconvulsant effect. Mice with acute and/or chronic infection had a substantial lower seizure threshold than the uninfected mice. JZL 184, ACEA and AM630 inhibited proconvulsant effect of Toxoplasmosis, while AM251 and HU308 intensified proconvulsant effect of Toxoplasmosis.CB receptors play a role in proconvulsant effect of Toxoplasmosis in mice.

Investigation of the Incidence and Perinatal Outcomes of Acute Toxoplasma Infection in Pregnancy: Results from the Tertiary Center of the Eastern Black Sea Region

Investigation of the Incidence and Perinatal Outcomes of Acute Toxoplasma Infection in Pregnancy: Results from the Tertiary Center of the Eastern Black Sea Region

Acute Toxoplasma infection in pregnant women worldwide: Asystematic review and meta-analysis.

BackgroundAcute Toxoplasma infection (ATI) during pregnancy, if left untreated, can cause severe adverse outcomes for the fetus and newborn. Here, we undertook a meta-analysis to estimate the worldwide prevalence of ATI in pregnant women.MethodsWe searched international databases for studies published between January 1988 and November 2018. We included population-based cross-sectional and prospective cohort studies that reported the prevalence of ATI in pregnant women. Data were synthesized using a random effect model to calculate the overall prevalence of ATI (with a 95% CI) in six WHO regions and globally. We also performed linear meta-regression analyses to investigate associations of maternal, socio-demographic, geographical and climate parameters with the prevalence of ATI.ResultsIn total, 217 studies comprising 902,228 pregnant women across 74 countries were included in the meta-analysis. The overall prevalence of ATI in pregnant women globally was 1.1% (95% CI: 0.9–1.2%). In studies where more strict criteria for ATI were used, the overall prevalence was 0.6% (95% CI: 0.4–0.7%). The prevalence was highest in the Eastern Mediterranean region (2.5%; 95%CI: 1.7–3.4%) and lowest in the European region (0.5%; 95% CI: 0.4–0.7%). A significantly higher prevalence of ATI was found in countries with lower income levels (P = 0.027), lower human development indices (P = 0.04), higher temperatures (P = 0.02) and lower latitudes (P = 0.005) and longitudes (P = 0.02).ConclusionsThe risk of acquiring ATI during gestation is clinically important and preventive measures to avoid exposure of pregnant women to Toxoplasma infection should be strictly applied.

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.

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

BackgroundThe 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.MethodsWe 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.ResultsA 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.ConclusionsThe 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.

Toxoplasmosis accelerates acquisition of epilepsy in rats undergoing chemical kindling

Epilepsy is one of the most common neurologic disorders worldwide with no distinguishable cause in 60% of patients. One-third of the world population has been infected with Toxoplasma gondii. This intracellular parasite has high tropism for excitable cells including neurons. We assessed impact of acute and chronic T. gondii infection on epileptogenesis in pentylenetetrazole (PTZ) kindling model in male rats. T. gondii cysts were administered to rats by intraperitoneal (i.p.) injection. The presence of T. gondii cysts in the brain of rats was verified by hematoxylin-eosin staining. One and eight weeks after cysts injection, as acute and chronic phases of infection, PTZ (30mg/kg, i.p.) was injected to the rats every other day until manifestation of generalized seizures. Histologic findings confirmed cerebral toxoplasmosis in rats. The rats with acute or chronic Toxoplasma infection became kindled by lower number of PTZ injections (14.8±1 and 13.6±1 injections, respectively) compared to corresponding uninfected rats (18.7±1 and 16.9±1 injections, p<0.05). Toxoplasma infection increased the rate of kindling in rats. The chronically-infected rats achieved focal and also generalized seizures earlier than the rats with acute infection. Toxoplasmosis might be considered as a risk factor for acquisition of epilepsy.

Immunoglobulin M indirect-fluorescent antibody test for the diagnosis of acute toxoplasmosis during pregnancy in the avidity era: A 14-year experience at the Tuscany Reference Center for Infectious Diseases in Pregnancy, Florence, Italy.

The aim of this study was to evaluate immunoglobulin M indirect-fluorescent antibody test (IgM IFAT) for the diagnosis of acute or chronic Toxoplasma infection in pregnancy. Pregnant women with suspected acute toxoplasmosis referred to the Tuscany Reference Center for Infectious Diseases in Pregnancy during the period 1998-2012 were retrospectively enrolled. All women were tested with a panel of serological tests, including enzyme-linked immunosorbent assay for IgG avidity and IgM IFAT. On the basis of anamnestic, clinical, and serological criteria, pregnant women were classified into three groups: recently infected (RI), latently infected (LI), and doubtful latently infected (DLI). Patients classified as DLI were excluded from the analysis. The association between IgM IFAT (positive or negative) and the diagnosis of infection (acute or chronic) was assessed. Positive predictive value and negative predictive value of the IgM IFAT were calculated. A total of 810 pregnant women were enrolled in the study: 302 in the RI group and 508 in the LI group. Fifty-two women classified as DLI were excluded. IgM IFAT was positive in 172 out of 302 (56.9%) pregnant women in the RI group and in 29 out of 508 (5.7%) in the LI group. The positive predictive value and negative predictive value of IgM IFAT in predicting RI was 85.6% and 78.6%, respectively. IgM IFAT has reasonable sensitivity and specificity in diagnosing recent infection and, mostly in case of borderline avidity test, could be considered as a further aid for an accurate diagnosis of acute toxoplasmosis in pregnancy.