Patterns of Hydrocephalus Caused by Congenital Toxoplasma gondii Infection Associate With Parasite Genetics.

Four anatomical patterns of hydrocephalus secondary to congenital Toxoplasma gondii infection were identified and characterized for infants enrolled in the National Collaborative Chicago-based Congenital Toxoplasmosis Study. Analysis of parasite serotype revealed that different anatomical patterns associate with Type-II vs Not-Exclusively Type-II strains (NE-II) (P = .035).

Clustering of Toxoplasma gondii Infections Within Families of Congenitally Infected Infants.

BACKGROUND: Family clusters and epidemics of toxoplasmosis in North, Central, and South America led us to determine whether fathers of congenitally infected infants in the National Collaborative Chicago-Based Congenital Toxoplasmosis Study (NCCCTS) have a high incidence of Toxoplasma gondii infection. METHODS: We analyzed serum samples collected from NCCCTS families between 1981 and 2013. Paternal serum samples were tested for T. gondii antibodies with immunoglobulin (Ig) G dye test and IgM enzyme-linked immunosorbent assay. Additional testing of paternal serum samples was performed with differential-agglutination and IgG avidity tests when T. gondii IgG and IgM results were positive and serum samples were collected by the 1-year visit of the congenitally infected child. Prevalence of paternal seropositivity and incidence of recent infection were calculated. We analyzed whether certain demographics, maternal parasite serotype, risk factors, or maternal/infant clinical manifestations were associated with paternal T. gondii infection status. RESULTS: Serologic testing revealed a high prevalence (29 of 81; 36%) of T. gondii infection in fathers, relative to the average seropositivity rate of 9.8% for boys and men aged 12-49 years in the United States between 1994 and 2004 (P < .001). Moreover, there was a higher-than-expected incidence of recent infections among fathers with serum samples collected by the 1-year visit of their child (6 of 45; 13%; P < .001). No demographic patterns or clinical manifestations in mothers or infants were associated with paternal infections, except for sandbox exposure. CONCLUSIONS: The high prevalence of chronic and incidence of recent T. gondii infections in fathers of congenitally infected children indicates that T. gondii infections cluster within families in North America. When a recently infected person is identified, family clustering and community risk factors should be investigated for appropriate clinical management.

ALOX12 in human toxoplasmosis.

ALOX12 is a gene encoding arachidonate 12-lipoxygenase (12-LOX), a member of a nonheme lipoxygenase family of dioxygenases. ALOX12 catalyzes the addition of oxygen to arachidonic acid, producing 12-hydroperoxyeicosatetraenoic acid (12-HPETE), which can be reduced to the eicosanoid 12-HETE (12-hydroxyeicosatetraenoic acid). 12-HETE acts in diverse cellular processes, including catecholamine synthesis, vasoconstriction, neuronal function, and inflammation. Consistent with effects on these fundamental mechanisms, allelic variants of ALOX12 are associated with diseases including schizophrenia, atherosclerosis, and cancers, but the mechanisms have not been defined. Toxoplasma gondii is an apicomplexan parasite that causes morbidity and mortality and stimulates an innate and adaptive immune inflammatory reaction. Recently, it has been shown that a gene region known as Toxo1 is critical for susceptibility or resistance to T. gondii infection in rats. An orthologous gene region with ALOX12 centromeric is also present in humans. Here we report that the human ALOX12 gene has susceptibility alleles for human congenital toxoplasmosis (rs6502997 [P, <0.000309], rs312462 [P, <0.028499], rs6502998 [P, <0.029794], and rs434473 [P, <0.038516]). A human monocytic cell line was genetically engineered using lentivirus RNA interference to knock down ALOX12. In ALOX12 knockdown cells, ALOX12 RNA expression decreased and levels of the ALOX12 substrate, arachidonic acid, increased. ALOX12 knockdown attenuated the progression of T. gondii infection and resulted in greater parasite burdens but decreased consequent late cell death of the human monocytic cell line. These findings suggest that ALOX12 influences host responses to T. gondii infection in human cells. ALOX12 has been shown in other studies to be important in numerous diseases. Here we demonstrate the critical role ALOX12 plays in T. gondii infection in humans.

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.

Prematurity and severity are associated with Toxoplasma gondii alleles (NCCCTS, 1981-2009).

BACKGROUND: Congenital toxoplasmosis is a severe, life-altering disease in the United States. A recently developed enzyme-linked immunosorbent assay (ELISA) distinguishes Toxoplasma gondii parasite types (II and not exclusively II [NE-II]) by detecting antibodies in human sera that recognize allelic peptide motifs of distinct parasite types. METHODS: ELISA determined parasite serotype for 193 congenitally infected infants and their mothers in the National Collaborative Chicago-based Congenital Toxoplasmosis Study (NCCCTS), 1981-2009. Associations of parasite serotype with demographics, manifestations at birth, and effects of treatment were determined. RESULTS: Serotypes II and NE-II occurred in the United States with similar proportions during 3 decades. For persons diagnosed before or at birth and treated in infancy, and persons diagnosed after 1 year of age who missed treatment in infancy, proportions were similar (P = .91). NE-II serotype was more common in hot, humid regions (P = .02) but was also present in other regions. NE-II serotype was associated with rural residence (P < .01), lower socioeconomic status (P < .001), and Hispanic ethnicity (P < .001). Prematurity (P = .03) and severe disease at birth (P < .01) were associated with NE-II serotype. Treatment with lower and higher doses of pyrimethamine with sulfadizine improved outcomes relative to those outcomes of persons in the literature who did not receive such treatment. CONCLUSIONS: Type II and NE-II parasites cause congenital toxoplasmosis in North America. NE-II serotype was more prevalent in certain demographics and associated with prematurity and severe disease at birth. Both type II and NE-II infections improved with treatment. CLINICAL TRIALS REGISTRATION: NCT00004317.

Unrecognized ingestion of Toxoplasma gondii oocysts leads to congenital toxoplasmosis and causes epidemics in North America.

BACKGROUND: Congenital toxoplasmosis presents as severe, life-altering disease in North America. If mothers of infants with congenital toxoplasmosis could be identified by risks, it would provide strong support for educating pregnant women about risks, to eliminate this disease. Conversely, if not all risks are identifiable, undetectable risks are suggested. A new test detecting antibodies to sporozoites demonstrated that oocysts were the predominant source of Toxoplasma gondii infection in 4 North American epidemics and in mothers of children in the National Collaborative Chicago-based Congenital Toxoplasmosis Study (NCCCTS). This novel test offered the opportunity to determine whether risk factors or demographic characteristics could identify mothers infected with oocysts. METHODS: Acutely infected mothers and their congenitally infected infants were evaluated, including in-person interviews concerning risks and evaluation of perinatal maternal serum samples. RESULTS: Fifty-nine (78%) of 76 mothers of congenitally infected infants in NCCCTS had primary infection with oocysts. Only 49% of these mothers identified significant risk factors for sporozoite acquisition. Socioeconomic status, hometown size, maternal clinical presentations, and ethnicity were not reliable predictors. CONCLUSIONS: Undetected contamination of food and water by oocysts frequently causes human infections in North America. Risks are often unrecognized by those infected. Demographic characteristics did not identify oocyst infections. Thus, although education programs describing hygienic measures may be beneficial, they will not suffice to prevent the suffering and economic consequences associated with congenital toxoplasmosis. Only a vaccine or implementation of systematic serologic testing of pregnant women and newborns, followed by treatment, will prevent most congenital toxoplasmosis in North America.

Outcomes of hydrocephalus secondary to congenital toxoplasmosis.

OBJECTIVE: Hydrocephalus occurs in children with congenital toxoplasmosis and can lead to severe disability. In these cases, the decision to intervene is often influenced by the expectation of neurological recovery. In this study, clinical responses to neurosurgical intervention in children with hydrocephalus secondary to congenital toxoplasmosis are characterized. METHODS: Sixty-five participants with hydrocephalus due to congenital Toxoplasma gondii infection were evaluated as part of the National Collaborative Chicago-based Congenital Toxoplasmosis Study, and their neuroradiographic findings were reviewed. Clinical outcomes were scored on the basis of cognition and motor skills through the use of IQ scores and Gross Motor Function Classification System (GMFCS) level. Outcomes were then analyzed in relation to approach to management, anatomy of hydrocephalus, and time from diagnosis of hydrocephalus to surgical intervention. RESULTS: There was considerable variation in the outcomes of patients whose hydrocephalus was treated in early life, ranging from normal cognitive and motor function to profound developmental delay and functional limitation. Of the 65 participants included in the study, IQ and GMFCS level were available for 46 (70.8%). IQ and motor score were highly correlated (r = -0.82, p < 0.001). There were people with differing patterns of hydrocephalus or thickness of cortical mantle on initial presentation who had favorable outcomes. Time to neurosurgical intervention data were available for 31 patients who underwent ventriculoperitoneal (VP) shunt placement. Delayed shunt placement beyond 25 days after diagnosis of hydrocephalus was associated with greater cognitive impairment (p = 0.02). Motor impairment also appeared to be associated with shunt placement beyond 25 days but the difference did not achieve statistical significance (p = 0.13). Among those with shunt placement within 25 days after diagnosis (n = 19), the mean GMFCS level was 1.9 ± 1.6 (range 1-5). Five (29.4%) of 17 of these patients were too disabled to participate in formal cognitive testing, after excluding 2 patients with visual difficulties or language barriers that precluded IQ testing. Of the patients who had VP shunt placement 25 or more days after diagnosis (n = 12), the mean GMFCS level was 2.7 ± 1.4 (range 1-4). Of these, 1 could not participate in IQ testing due to severe visual difficulties and 8 (72.7%) of the remaining 11 due to cognitive disability. CONCLUSIONS: VP shunt placement in patients with hydrocephalus caused by congenital toxoplasmosis can contribute to favorable clinical outcomes, even in cases with severe hydrocephalus on neuroimaging. Shunt placement within 25 days of diagnosis was statistically associated with more favorable cognitive outcomes. Motor function appeared to follow the same pattern although it did not achieve statistical significance.

Publisher Correction: Toxoplasma Modulates Signature Pathways of Human Epilepsy, Neurodegeneration & Cancer.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

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.

Toxoplasma Modulates Signature Pathways of Human Epilepsy, Neurodegeneration & Cancer.

One third of humans are infected lifelong with the brain-dwelling, protozoan parasite, Toxoplasma gondii. Approximately fifteen million of these have congenital toxoplasmosis. Although neurobehavioral disease is associated with seropositivity, causality is unproven. To better understand what this parasite does to human brains, we performed a comprehensive systems analysis of the infected brain: We identified susceptibility genes for congenital toxoplasmosis in our cohort of infected humans and found these genes are expressed in human brain. Transcriptomic and quantitative proteomic analyses of infected human, primary, neuronal stem and monocytic cells revealed effects on neurodevelopment and plasticity in neural, immune, and endocrine networks. These findings were supported by identification of protein and miRNA biomarkers in sera of ill children reflecting brain damage and T. gondii infection. These data were deconvoluted using three systems biology approaches: "Orbital-deconvolution" elucidated upstream, regulatory pathways interconnecting human susceptibility genes, biomarkers, proteomes, and transcriptomes. "Cluster-deconvolution" revealed visual protein-protein interaction clusters involved in processes affecting brain functions and circuitry, including lipid metabolism, leukocyte migration and olfaction. Finally, "disease-deconvolution" identified associations between the parasite-brain interactions and epilepsy, movement disorders, Alzheimer's disease, and cancer. This "reconstruction-deconvolution" logic provides templates of progenitor cells' potentiating effects, and components affecting human brain parasitism and diseases.

Outcome of treatment for congenital toxoplasmosis, 1981-2004: the National Collaborative Chicago-Based, Congenital Toxoplasmosis Study.

BACKGROUND: Without treatment, congenital toxoplasmosis has recurrent, recrudescent, adverse outcomes. Long-term follow-up of infants with congenital toxoplasmosis treated throughout their first year of life with pyrimethamine and sulfadiazine has not been reported. METHODS: Between 1981 and 2004, one hundred twenty infants (current mean age +/- standard deviation, 10.5 +/- 4.8 years) with congenital toxoplasmosis were treated with 1 of 2 doses of pyrimethamine plus sulfadiazine; therapy was initiated shortly after birth and continued for 12 months. Children who received treatment were evaluated at birth and at predetermined intervals; the focus of the evaluations was on prespecified end points: motor abnormalities, cognitive outcome, vision impairment, formation of new eye lesions, and hearing loss. RESULTS: Treatment of infants without substantial neurologic disease at birth with pyrimethamine and sulfadiazine for 1 year resulted in normal cognitive, neurologic, and auditory outcomes for all patients. Treatment of infants who had moderate or severe neurologic disease (as defined in this article in the Treatments subsection of Methods) at birth resulted in normal neurologic and/or cognitive outcomes for >72% of the patients, and none had sensorineural hearing loss. Ninety-one percent of children without substantial neurologic disease and 64% of those with moderate or severe neurologic disease at birth did not develop new eye lesions. Almost all of these outcomes are markedly better than outcomes reported for children who were untreated or treated for 1 month in earlier decades (P<.01 to P<.001). Sex and severity of disease were comparable in our 2 treatment groups, and no significant differences in efficacy or toxicity were noted between the 2 treatment groups (P > .05). CONCLUSIONS: Although not all children did well with treatment, the favorable outcomes we noted indicate the importance of diagnosis and treatment of infants with congenital toxoplasmosis.

Identification of a sporozoite-specific antigen from Toxoplasma gondii.

Reduction of risk for human and food animal infection with Toxoplasma gondii is hampered by the lack of epidemiological data documenting the predominant routes of infection (oocyst vs. tissue cyst consumption) in horizontally transmitted toxoplasmosis. Existing serological assays can determine previous exposure to the parasite, but not the route of infection. We have used difference gel electrophoresis, in combination with tandem mass spectroscopy and Western blot, to identify a sporozoite-specific protein (T. gondii embryogenesis-related protein [TgERP]), which elicited antibody and differentiated oocyst- versus tissue cyst-induced infection in pigs and mice. The recombinant protein was selected from a cDNA library constructed from T. gondii sporozoites; this protein was used in Western blots and probed with sera from T. gondii -infected humans. Serum antibody to TgERP was detected in humans within 6-8 mo of initial oocyst-acquired infection. Of 163 individuals in the acute stage of infection (anti- T. gondii IgM detected in sera, or < 30 in the IgG avidity test), 103 (63.2%) had detectable antibodies that reacted with TgERP. Of 176 individuals with unknown infection route and in the chronic stage of infection (no anti- T. gondii IgM detected in sera, or > 30 in the IgG avidity test), antibody to TgERP was detected in 31 (17.6%). None of the 132 uninfected individuals tested had detectable antibody to TgERP. These data suggest that TgERP may be useful in detecting exposure to sporozoites in early T. gondii infection and implicates oocysts as the agent of infection.

Impact of visual impairment on measures of cognitive function for children with congenital toxoplasmosis: implications for compensatory intervention strategies.

OBJECTIVES: The purpose of this work was to determine whether visual impairment caused by toxoplasmic chorioretinitis is associated with impaired performance of specific tasks on standardized tests of cognitive function. If so, then we worked to determine whether there are patterns in these difficulties that provide a logical basis for development of measures of cognitive function independent of visual impairment and compensatory intervention strategies to facilitate learning for such children. METHODS: Sixty-four children with congenital toxoplasmosis with intelligence quotient scores > or = 50 and visual acuity sufficient to cooperate with all of the intelligence quotient subscales had assessments of their vision, appearance of their retinas, and cognitive testing performed between 3.5 and 5 years of age. These evaluations took place between 1981 and 1998 as part of a longitudinal study to determine outcome of congenital toxoplasmosis. Children were evaluated at 3.5 or 5 (37 children) or both 3.5 and 5 (27 children) years of age. Cognitive function was measured using the Wechsler Preschool and Primary Scale of Intelligence-Revised. Wechsler Preschool and Primary Scale of Intelligence-Revised scale scores were compared for children grouped as those children who had normal visual acuity in their best eye (group 1), and those who had impaired vision in their best eye (acuity < 20/40) because of macular disease (group 2). Demographic characteristics were compared for children in the 2 groups. Test scores were compared between groups using all of the 3.5-year-old visits, all of the 5-year-old visits, and using each child's "last" visit (ie, using the 5-year-old test results when a child was tested at both 3.5 and 5 years of age or only at 5 years, otherwise using the 3.5-year-old test results). The results were similar and, therefore, only the results from the last analysis are reported here. RESULTS: There were 48 children with normal visual acuity in their best eye (group 1) and 16 children with impaired vision because of macular involvement in their best eye (group 2). Ethnicity and socioeconomic scores were similar. There was a significantly greater proportion of males in group 2 compared with group 1 (81% vs 46%). There was no significant diminution in Wechsler Preschool and Primary Scale of Intelligence-Revised test scores between 3.5 and 5 years of age for the 27 children tested at both of these ages. Verbal intelligence quotient, performance intelligence quotient, full-scale intelligence quotient scores, and all of the scaled scores except arithmetic and block design were significantly lower for children in group 2 compared with group 1. The majority of the differences remained statistically significant or borderline significant after adjusting for gender. However, the difference in overall verbal scores does not remain statistically significant. Mean +/- SD verbal (98 +/- 20) and performance (95 +/- 17) intelligence quotients were not significantly different for children in group 1. However, verbal (88 +/- 13) and performance intelligence quotients (78 +/- 17) were significantly different for children in group 2. For children in group 2, their lowest scale scores were in object assembly, geometric design, mazes, and picture completion, all timed tests that involved visual discrimination of linear forms with small intersecting lines. In the 2 scales scored that did not differ between groups 1 and 2, arithmetic and block design, timing and vision but not linear forms were components of the tasks. Children with monocular and binocular normal visual acuity did not differ in verbal, performance, or full-scale intelligence quotients or any of the subscale tests. Difficulty with sight or concomitant neurologic involvement also seemed to impact the ability to acquire information, comprehension skills, and vocabulary and performance in similarities testing. After controlling for gender, however, these differences were diminished, and there were no longer differences in overall verbal scores. As noted above, results were generally similar when all of the tests for 3.5-year-olds or 5-year-olds were analyzed separately. At the 3.5-year visit there were fewer significant differences between the 2 groups for the verbal components than at the 5-year visit. CONCLUSIONS: In children with congenital toxoplasmosis and bilateral macular disease (group 2) because of toxoplasmic chorioretinitis, scaled scores were lowest on timed tests that require discrimination of fine intersecting lines. Although the severity of ocular and neurologic involvement is often congruent in children with congenital toxoplasmosis, ophthalmologic involvement seems to account for certain specific limitations on tests of cognitive function. Children with such visual impairment compensate with higher verbal skills, but their verbal scores are still less than those of children with normal vision, and in some cases significantly so, indicating that vision impairment might affect other aspects of cognitive testing. Patterns of difficulties noted in the subscales indicate that certain compensatory intervention strategies to facilitate learning and performance may be particularly helpful for children with these impairments. These patterns also provide a basis for the development of measures of cognitive function independent of visual impairment.

Risk factors for Toxoplasma gondii infection in mothers of infants with congenital toxoplasmosis: Implications for prenatal management and screening.

OBJECTIVE: The purpose of this study was to determine whether demographic characteristics, history of exposure to recognized transmission vehicles, or illness that was compatible with acute toxoplasmosis during gestation identified most mothers of infants with congenital toxoplasmosis. STUDY DESIGN: Mothers of 131 infants and children who were referred to a national study of treatment for congenital toxoplasmosis were characterized demographically and questioned concerning exposure to recognized risk factors or illness. RESULTS: No broad demographic features identified populations that were at risk. Only 48% of mothers recognized epidemiologic risk factors (direct or indirect exposure to raw/undercooked meat or to cat excrement) or gestational illnesses that were compatible with acute acquired toxoplasmosis during pregnancy. CONCLUSION: Maternal risk factors or compatible illnesses were recognized in retrospect by fewer than one half of North American mothers of infants with toxoplasmosis. Educational programs might have prevented acquisition of Toxoplasma gondii by those mothers who had clear exposure risks. However, only systematic serologic screening of all pregnant women at prenatal visits or of all newborn infants at birth would prevent or detect a higher proportion of these congenital infections.