Longitudinal study of new eye lesions in treated congenital toxoplasmosis

Long-term Ocular Outcomes in Congenital Toxoplasmosis Treated Perinatally

BACKGROUND

Congenital toxoplasmosis (CT) can be accompanied by serious organ manifestations, particularly retinochoroiditis, and may occur throughout life. We aimed to monitor long-term ocular prognosis in a large French cohort of patients with CT and its changes over time in the context of mandatory prenatal screening (since 1992) and incidence decrease since 2008.

METHODS

Patients with CT diagnosed between 1987 and 2021 were prospectively included and followed for up to 35 years. The effect of the period of conception on the risk of first retinochoroiditis has been tested using a flexible extension of the Cox model. Incidence rates of retinochoroiditis were estimated.

RESULTS

A total of 646 infected live born children were followed for a median of 12 years (range, 0.5-35); 187 patients (29%) had at least 1 ocular lesion (first at a median age of 5 years; range, 0-26 years) with peaks at 7 and 12 years. Early maternal infection and the presence of nonocular signs at birth were associated with a higher risk of retinochoroiditis, whereas delayed diagnosis of CT (after birth versus before or at birth) was associated with a lower risk (13% decrease for each additional month after birth; P = .01). A period effect for the risk of developing retinochoroiditis in patients born after 2008 was not detected.

CONCLUSIONS

Despite prenatal screening and prolonged perinatal treatment, retinochoroiditis is not a rare event in French patients with CT and can occur well into adulthood, with peak incidences at 7 and 12 years of age. It rarely causes severe damage but warrants regular follow-up into adulthood.

Diagnosis of Congenital Toxoplasmosis: Challenges and Management Outcomes

Introduction Congenital toxoplasmosis (CT), despite being mostly subclinical at birth, can cause disabling disease in the fetus and lead to long-term sequelae. It is an important cause of chorioretinitis in infants and adolescents. Data on postnatal treatment are controversial, and there is a lack of universal guidelines. Methods A cross-sectional study of newborns with suspected CT was conducted between January 2007 and December 2021. Results Seventy-one patients with suspected CT were included. During pregnancy, 64 (90.1%) of the mothers underwent therapy, of which 59 (83.1%) with spiramycin. Amniocentesis identified one positive polymerase chain reaction assay. Most newborns were asymptomatic with normal laboratory, ophthalmological, and hearing screening. There was one case of hyperproteinorrachia. Fifty-seven patients (80.3%) started treatment: 42 (73.7%) with spiramycin, seven (12.3%) with pyrimethamine, sulfadiazine, and folinic acid (P+S+FA), and eight (14%) with P+S+FA intercalated with spiramycin. Adverse effects were found in 11 (19.3%) cases, mainly neutropenia. After investigation, we found three confirmed CT cases corresponding to 4.2% of suspected cases and an incidence of 0.4 per 10,000 births. All had normal clinical and laboratory exams in the neonatal period and started P+S+FA, fulfilling 12 months of therapy. During the follow-up, all presented normal psychomotor development without any long-term sequelae. Conclusion The lower incidence in our study, compared to the incidence in Europe, may be related to the decline in the prevalence of toxoplasmosis as well as the effectiveness of measures to prevent primary infection and a well-established program of antenatal screening, followed by the early initiation of treatment during pregnancy to prevent vertical transmission.

Risk factors for recurrences and visual impairment in patients with ocular toxoplasmosis: A systematic review and meta-analysis

BACKGROUND

Ocular toxoplasmosis (OT) is caused by the parasite Toxoplasma gondii. OT is the leading cause of posterior uveitis globally; it is a recurrent disease that may result in visual impairment and blindness. This systematic review and meta-analysis aim to summarize and evaluate the risk factors for recurrences, visual impairment, and blindness described in the literature worldwide.

METHODS AND FINDINGS

We performed a systematic literature search in PubMed, Embase, VHL, Cochrane Library, Scopus, and DANS EASY Archive. All studies reporting patients with clinically and serologically confirmed OT presenting any clinical or paraclinical factor influencing recurrences, visual impairment, and blindness were included. Studies presenting secondary data, case reports, and case series were excluded. An initial selection was made by title and abstract, and then the studies were reviewed by full text where the eligible studies were selected. Then, the risk of bias was assessed through validated tools. Data were extracted using a validated extraction format. Qualitative synthesis and quantitative analysis were done. This study was registered on PROSPERO (CRD42022327836).

RESULTS

Seventy two studies met the inclusion criteria. Fifty-three were summarized in the qualitative synthesis in three sections: clinical and environmental factors, parasite and host factors, and treatment-related factors. Of the 72 articles, 39 were included in the meta-analysis, of which 14 were conducted in South America, 13 in Europe, four in Asia, three multinational, two in North America and Central America, respectively, and only one in Africa. A total of 4,200 patients with OT were analyzed, mean age ranged from 7.3 to 65.1 year of age, with similar distribution by sex. The frequency of recurrences in patients with OT was 49% (95% CI 40%-58%), being more frequent in the South American population than in Europeans. Additionally, visual impairment was presented in 35% (95% CI 25%-48%) and blindness in 20% (95% CI 13%-30%) of eyes, with a similar predominance in South Americans than in Europeans. On the other hand, having lesions near the macula or adjacent to the optic nerve had an OR of 4.83 (95% CI; 2.72-8.59) for blindness, similar to having more than one recurrence that had an OR of 3.18 (95% CI; 1.59-6.38). Finally, the prophylactic therapy with Trimethoprim/Sulfamethoxazole versus the placebo showed a protective factor of 83% during the first year and 87% in the second year after treatment.

CONCLUSION

Our Systematic Review showed that clinical factors such as being older than 40 years, patients with de novo OT lesions or with less than one year after the first episode, macular area involvement, lesions greater than 1 disc diameter, congenital toxoplasmosis, and bilateral compromise had more risk of recurrences. Also, environmental and parasite factors such as precipitations, geographical region where the infection is acquired, and more virulent strains confer greater risk of recurrences. Therefore, patients with the above mentioned clinical, environmental, and parasite factors could benefit from using prophylactic therapy.

Prevention of congenital toxoplasmosis in France using prenatal screening: A decision-analytic economic model

Background

Toxoplasma gondii is one of the world’s most common parasites. Primary infection of the mother during pregnancy can lead to transmission to the fetus with risks of brain and eye lesions, which may cause lifelong disabilities. France instituted a national program based on monthly retesting of susceptible pregnant women to reduce the number of severe cases through prompt antenatal and postnatal treatment and follow-up.

Objective

To evaluate the ability of the French prenatal retesting program to reduce the lifetime costs of congenital toxoplasmosis.

Methods

We measured and then compared the costs and benefits of screening vs. not screening using decision-tree modelling. It included direct and indirect costs to society of treatment and care, and the lifetime lost earnings of children and caregivers. A probabilistic sensitivity analysis was carried out.

Findings

Total lifetime costs per live born child identified as congenitally infected were estimated to be €444 for those identified through prenatal screening vs €656 for those who were not screened. Estimates were robust to changes in all costs of diagnosis, treatment, and sequelae.

Interpretation

Screening for the prevention of the congenital T. gondii infection in France is cost saving at €212 per birth. Compared with no screening, screening every pregnant woman in France for toxoplasmosis in 2020 would have saved the country €148 million in addition to reducing or eliminating the devastating physical and emotional suffering caused by T. gondii. Our findings reinforce the conclusions of other decision-analytic modelling of prenatal toxoplasmosis screening.

Long-Term Outcomes in Children with Congenital Toxoplasmosis-A Systematic Review

Even in the absence of manifestations at birth, children with congenital toxoplasmosis (CT) may develop serious long-term sequelae later in life. This systematic review aims to present the current state of knowledge to base an informed decision on how to optimally manage these pregnancies and children. For this, a systematic literature search was performed on 28 July 2022 in PubMed, CENTRAL, ClinicalTrials.gov, Google Scholar and Scopus to identify all prospective and retrospective studies on congenital toxoplasmosis and its long-term outcomes that were evaluated by the authors. We included 31 research papers from several countries. Virulent parasite strains, low socioeconomic status and any delay of treatment seem to contribute to a worse outcome, whereas an early diagnosis of CT as a consequence of prenatal screening may be beneficial. The rate of ocular lesions in treated children increases over time to 30% in European and over 70% in South American children and can be considerably reduced by early treatment in the first year of life. After treatment, new neurological manifestations are not reported, while ocular recurrences are observed in more than 50% of patients, with a mild to moderate impact on quality of life in European cohorts when compared to a significantly reduced quality of life in the more severely affected South American children. Though CT is rare and less severe in Europe when compared with South America, antenatal screening is the only effective way to diagnose and treat affected individuals at the earliest possible time in order to reduce the burden of disease and achieve satisfying outcomes.

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.

Long-term impact of congenital toxoplasmosis on phenotypic and functional features of circulating leukocytes from infants one year after treatment onset

Changes in immune response of children with congenital toxoplasmosis (CT) regarding infection evolution and therapeutic intervention was addressed. Infants with CT presented increased counts of monocytes, CD3^-CD16^-CD56^High, CD3⁺CD56⁺ and CD4⁺ T-cells 1-year after treatment onset (TOXO_1-yearAT). Smaller numbers of CD3^-CD16^-CD56⁺ and TCRγδ⁺ T-cells were specifically observed in infants with retinochoroidal lesions (L(+)). When infants were classified based on the baseline status, expansion of CD3^-CD16^-CD56^High and CD4⁺ T-cells were observed in L(+) who had active, active/cicatricial or cicatricial lesions. Infants who had active or active/cicatricial lesions display augmented numbers of monocytes, CD3^-CD16⁺CD56⁺, CD3⁺CD56⁺, CD8⁺DR⁺ and TCRγδ⁺ T-cells and those with active/cicatricial or cicatricial at baseline displayed increase in CD14⁺CD64⁺ monocytes. Moreover, all L(+) had increased IFN-γ⁺ and IL-10⁺ CD4⁺ T-cells, while L(-) had increased ratios of TNF⁺, IFN-γ⁺ and IL-4⁺ NK-cells upon antigen-specific stimulation. Persistent alterations in leukocytes in TOXO_1-yearAT suggest long-term sequels in the immune system of infants with CT.

Scoping Review of Toxoplasma Postinfectious Sequelae

Previous economic estimates of infection with Toxoplasma gondii and chronic sequelae following infection lack sufficient data to establish the true burden of disease and its chronic sequelae. This scoping review aims to fill this gap by updating existing literature regarding the development of postinfectious sequelae following T. gondii infection. Literature published between January 1, 2000, and November 6, 2018, in PubMed, EMBASE, and Scopus was searched for a wide range of postinfectious sequelae and economic estimate terms. This scoping review includes summaries from the 108 articles covering 5 main groupings of outcomes (categories are not exclusive) including vision disorders (n = 58), psychological and mental health disorders (n = 27), neurological disorders (n = 17), fetal death and infection (n = 15), and hearing loss (n = 6), as well as a description of other outcomes reported. While the majority of the included studies assessed the incidence of these outcomes postinfection, very few followed participants long-term. These prospective studies are needed to understand the true burden of postinfectious sequelae over the life course, particularly because congenital infection with Toxoplasma can lead to severe outcomes for newborns. This scoping review can be used as an important resource for other researchers wishing to conduct future systematic reviews and meta-analyses, as well as for policy makers interested in developing guidance for public and health care partners.

Ocular Outcome of Brazilian Patients With Congenital Toxoplasmosis

BACKGROUND

Retinochoroiditis is the most frequent manifestation of congenital toxoplasmosis. We aimed to describe the ocular outcome and factors that may influence the visual prognosis of these patients.

METHODS

Cohort of patients with confirmed congenital toxoplasmosis seen between 1996 and 2017 in Porto Alegre, southern Brazil.

RESULTS

Seventy-seven patients were included, of which 65 (85.5%) were identified by routine screening. Median age at the end of the follow-up was 10 years (minimum 2, maximum 25). Retinochoroiditis was present in 55 patients (71.4%). New retinochoroidal lesions developed after the first year of life in 77.8% of the patients who began treatment after the fourth month of life, compared with 35.2% among those treated before 4 months of life (relative risk = 0.45, 95% confidence intervals: 0.27-0.75, P = 0.02) and 33.3% among those treated before 2 months of life (relative risk = 0.42, 95% confidence intervals: 0.25-0.72, P = 0.01). There was a peak incidence of new retinochoroidal lesions between 4 and 5 years and another peak between 9 and 14 years, the latter only among girls. Thirty-four patients with retinochoroiditis were followed up for 10 years or more, and the school performance was appropriate in 28 (82.4%).

CONCLUSIONS

The high incidence of new retinochoroidal lesions during the follow-up period indicates the importance of long-term follow-up of patients with congenital toxoplasmosis. Initiating treatment within the first 4 months of life, especially within the first 2 months, was a protective factor against the later development of retinochoroiditis. Despite the usual favorable prognosis, the high morbidity of congenital toxoplasmosis in Brazil was confirmed.

Asymmetric eye size in an infant

Toxoplasmosis is an uncommon congenital infection in Canada, but one with potentially severe clinical manifestations, including fetal death. Neurologic and ocular manifestations are frequent in untreated disease; however, small eye size (microphthalmia) is a rare finding. This finding may be a marker of severe ocular disease. As universal screening does not occur in Canada, clinicians' early recognition is imperative, particularly given the lack of risk factors in many patients and the benefit that treatment may have even in initially asymptomatic disease. Here, we report a case of congenital toxoplasmosis and review the diagnostics and treatment of the infection.

Toxoplasmosis screening during pregnancy in France: Opinion of an expert panel for the CNGOF

Prenatal screening to prevent congenital toxoplasmosis as performed in France for several decades has been questioned in view of the decreasing incidence of this infection and the cost of testing. The French College of Obstetrics and Gynecology mandated a multidisciplinary panel of experts to perform a reassessment of the screening program in accordance with international good practice. In France, about 70% of pregnant women are not immune to T. gondii, and 0.2-0.25% become infected during pregnancy. The risk of maternal-fetal transmission of infection is on average 25-29% and depends greatly on the gestational age at seroconversion. In case of fetal transmission, the outcome is livebirth in 95% of cases, with latent congenital toxoplasmosis in 90% of cases and symptomatic forms in 10% of cases, of which 1/3 are severe and 2/3 moderate. Biological techniques have satisfactory performance regarding serologies for the diagnosis of maternal infections and PCR on amniotic fluid for the prenatal diagnosis of congenital toxoplasmosis. Primary prevention of toxoplasmosis is based on hygiene measures that are relatively simple, but poorly implemented. In case of maternal seroconversion, there is a strong case for prenatal prophylactic treatment as soon as possible (ideally within 3 weeks of seroconversion), spiramycin before 14 weeks of gestation (WG), and with a tendency to superiority of the pyrimethamine/sulfadiazine association over spiramycin beyond 14 W G, in order to reduce the risk of symptomatic congenital toxoplasmosis. In case of congenital toxoplasmosis, prompt initiation of treatment reduces the occurrence of cerebral signs and symptoms, as well as retinal lesions. Several medico-economic evaluations of the French toxoplasmosis screening program have been conducted including an individual cost-effectiveness approach with decision analysis which concluded on the profitability of prenatal screening as carried out in France (monthly surveillance of seronegative women, prenatal treatment in case of seroconversion, termination of pregnancy in severe forms). Though most international societies do not recommend systematic screening for mainly financial reasons, if congenital toxoplasmosis appears benign in France today, it is probably thanks to screening and the possibility of early treatment of fetuses and/or newborns. Thus, the panel recommends continuing for now the program in France for prevention of congenital toxoplasmosis.

Treatment of Toxoplasmosis: Historical Perspective, Animal Models, and Current Clinical Practice

Primary Toxoplasma gondii infection is usually subclinical, but cervical lymphadenopathy or ocular disease can be present in some patients. Active infection is characterized by tachyzoites, while tissue cysts characterize latent disease. Infection in the fetus and in immunocompromised patients can cause devastating disease. The combination of pyrimethamine and sulfadiazine (pyr-sulf), targeting the active stage of the infection, is the current gold standard for treating toxoplasmosis, but failure rates remain significant. Although other regimens are available, including pyrimethamine in combination with clindamycin, atovaquone, clarithromycin, or azithromycin or monotherapy with trimethoprim-sulfamethoxazole (TMP-SMX) or atovaquone, none have been found to be superior to pyr-sulf, and no regimen is active against the latent stage of the infection. Furthermore, the efficacy of these regimens against ocular disease remains uncertain. In multiple studies, systematic screening for Toxoplasma infection during gestation, followed by treatment with spiramycin for acute maternal infections and with pyr-sulf for those with established fetal infection, has been shown to be effective at preventing vertical transmission and minimizing the severity of congenital toxoplasmosis (CT). Despite significant progress in treating human disease, there is a strong impetus to develop novel therapeutics for both the acute and latent forms of the infection. Here we present an overview of toxoplasmosis treatment in humans and in animal models. Additional research is needed to identify novel drugs by use of innovative high-throughput screening technologies and to improve experimental models to reflect human disease. Such advances will pave the way for lead candidates to be tested in thoroughly designed clinical trials in defined patient populations.

Small GTPase Immunity-Associated Proteins Mediate Resistance to Toxoplasma gondii Infection in Lewis Rat

Rats vary in their susceptibilities to Toxoplasma gondii infection depending on the rat strain. Compared to the T. gondii-susceptible Brown Norway (BN) rat, the Lewis (LEW) rat is extremely resistant to T. gondii Thus, these two rat strains are ideal models for elucidating host mechanisms that are important for host resistance to T. gondii infection. Therefore, in our efforts to unravel molecular factors directing the protective early innate immune response in the LEW rat, we performed RNA sequencing analysis of the LEW versus BN rat with or without T. gondii infection. We identified three candidate small GTPase immunity-associated proteins (GIMAPs) that were upregulated (false discovery rate, 0.05) in the LEW rat in response to T. gondii infection. Subsequently, we engineered T. gondii-susceptible NR8383 rat macrophage cells for overexpression of LEW rat-derived candidate GIMAP 4, 5, and 6. By immunofluorescence analysis we observed that GIMAP 4, 5, and 6 in T. gondii-infected NR8383 cells each colocalized with GRA5, a parasite parasitophorous vacuole membrane (PVM) marker protein, suggesting their translocation to the PVM. Interestingly, overexpression of each candidate GIMAP in T. gondii-infected NR8383 cells induced translocation of LAMP1, a lysosome marker protein, to the T. gondii surface membrane. Importantly, overexpression of GIMAP 4, 5, or 6 individually inhibited intracellular T. gondii growth, with GIMAP 4 having the highest inhibitory effect. Together, our findings indicate that upregulation of GIMAP 4, 5, and 6 contributes to the robust refractoriness of the LEW rat to T. gondii through induction of lysosomal fusion to the otherwise nonfusogenic PVM.

High Frequency of Bone Marrow Depression During Congenital Toxoplasmosis Therapy in a Cohort of Children Identified by Neonatal Screening in Minas Gerais, Brazil

BACKGROUND

There are few studies reporting frequency and control of adverse events associated with congenital toxoplasmosis treatment. The objective of this study is to describe treatment adherence and adverse hematologic events in a cohort of children identified with congenital toxoplasmosis in Minas Gerais, Brazil.

METHODS

Children were treated with sulfadiazine, pyrimethamine and folinic acid and were evaluated clinically and by laboratory tests at regular intervals.

RESULTS

Of 146,307 live newborns who participated in the Neonatal Screening Program in Minas Gerais in 2006-2007, 190 had congenital toxoplasmosis. Among the 171 children whose treatment data were available, 73.1% completely adhered to antiparasitic therapy. Hematologic adverse events (macrocytic anemia and/or neutropenia and/or thrombocytopenia) were diagnosed in 44% of them. The most common adverse event was neutropenia (31%). In most cases, it was not severe and reversed after increase in folinic acid dosage (25.7%) or temporary treatment suspension (1.8%). No infections were observed in association with neutropenic events. Significant associations were detected between macrocytic anemia and lower weight Z score at first medical appointment (P = 0.03), and between severe neutropenia (<500/mm) and lower weight Z score toward the end of treatment (P = 0.04).

CONCLUSIONS

The high frequency of hematologic adverse events found, especially in malnourished children, highlight the importance of careful monitoring of these children throughout treatment, as well as considering nutritional aspects and the need for higher doses of folinic acid. With adequate monitoring, antiparasitic treatment was feasible and relatively safe in the setting of this large screening program for congenital toxoplasmosis.

Treatment of Congenital Toxoplasmosis: Safety of the Sulfadoxine-Pyrimethamine Combination in Children Based on a Method of Causality Assessment

BACKGROUND

The treatment of newborns and infants with congenital toxoplasmosis is standard practice. Some observational studies have examined safety in newborns, but most of these failed to provide sufficient details for a provisional assessment of causality. The aim of this study was to evaluate the clinical and biological adverse effects of the combination of sulfadoxine-pyrimethamine.

METHODS

Sixty-five children treated for 1 year with a combination of sulfadoxine-pyrimethamine (1 dose every 10 days) for congenital toxoplasmosis were followed up to evaluate abnormal hematological values and potential adverse events using a standardized method of causality assessment.

RESULTS

Nine patients (13.8%) presented at least 1 adverse clinical event that was nonspecific, such as diarrhea on the day of drug administration, vomiting and agitation. In 1 patient, erythema appeared at the end of the treatment and resolved within 10 days. None of these events was attributed to the treatment. Six patients (9.2%) developed an adverse hematological event (neutropenia, n = 3; eosinophilia, n = 2 and both anemia and eosinophilia, n = 1) that was considered to be possibly related to the sulfadoxine-pyrimethamine combination. Four treatments were temporarily interrupted, and toxicity was observed after readministration of treatment in 1 case only. However, none of these adverse events was life threatening.

CONCLUSIONS

According to our results and previously published data, the combination of sulfadoxine-pyrimethamine seems to be well tolerated. However, the sample size of our study was too small to rule out the risk of less frequent, but nevertheless severe, reactions and, in particular, of hypersensitivity reactions.

MHC Class I Chain-Related Gene A Polymorphisms and Linkage Disequilibrium with HLA-B and HLA-C Alleles in Ocular Toxoplasmosis

This study investigated whether polymorphisms of the MICA (major histocompatibility complex class I chain-related gene A) gene are associated with eye lesions due to Toxoplasma gondii infection in a group of immunocompetent patients from southeastern Brazil. The study enrolled 297 patients with serological diagnosis of toxoplasmosis. Participants were classified into two distinct groups after conducting fundoscopic exams according to the presence (n = 148) or absence (n = 149) of ocular scars/lesions due to toxoplasmosis. The group of patients with scars/lesions was further subdivided into two groups according to the type of the ocular manifestation observed: primary (n = 120) or recurrent (n = 28). Genotyping of the MICA and HLA alleles was performed by the polymerase chain reaction-sequence specific oligonucleotide technique (PCR-SSO; One Lambda®) and the MICA-129 polymorphism (rs1051792) was identified by nested polymerase chain reaction (PCR-RFLP). Significant associations involving MICA polymorphisms were not found. Although the MICA*002~HLA-B*35 haplotype was associated with increased risk of developing ocular toxoplasmosis (P-value = 0.04; OR = 2.20; 95% CI = 1.05–4.60), and the MICA*008~HLA-C*07 haplotype was associated with protection against the development of manifestations of ocular toxoplasmosis (P-value = 0.009; OR: 0.44; 95% CI: 0.22–0.76), these associations were not statistically significant after adjusting for multiple comparisons. MICA polymorphisms do not appear to influence the development of ocular lesions in patients diagnosed with toxoplasmosis in this study population.

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.

Ocular Involvement Following Postnatally Acquired Toxoplasma gondii Infection in Southern Brazil: A 28-Year Experience

PURPOSE

To determine the incidence of, and risk factors for, ocular involvement among people known to have postnatally acquired Toxoplasma gondii infection in a region of southern Brazil where there is a high prevalence of endemic disease.

DESIGN

Retrospective longitudinal cohort study.

METHODS

Records of 302 patients with serologic evidence of recent T gondii infection (a positive anti-T gondii IgM antibody test) from Erechim, Rio Grande do Sul state, Brazil (1974-2002) were analyzed. The incidence of ocular involvement was calculated in terms of person-years (PY) of follow-up. Risk factors for ocular involvement were analyzed using log-rank and Fisher exact tests.

RESULTS

At initial ocular examination (baseline), 30 patients (9.9%) had intraocular inflammation only (anterior chamber cells and flare, vitreous inflammatory reactions, retinal whitening), without clinically apparent necrotizing retinochoroiditis. At baseline, men were more likely to have ocular involvement (P = .043) and antiparasitic treatment was associated with less ocular involvement (P = .015). Follow-up examinations were performed on 255 patients (median follow-up, 13.7 months [range 0.4-261.9 months]). Among those without ocular involvement at baseline, the incidence of necrotizing retinochoroiditis was 6.4/100 PY. Patients >40 years of age at first IgM test had a greater risk of incident necrotizing retinochoroiditis (hazard ratio = 4.47, 95% CI = 1.67-11.93, P = .003) than younger patients. The incidence of recurrent necrotizing retinochoroiditis was 10.5/100 PY.

CONCLUSION

Isolated intraocular inflammatory reactions can be an initial manifestation of T gondii infection, with necrotizing retinochoroiditis occurring months or years later. Male sex and older age are risk factors for toxoplasmic retinochoroiditis. Antitoxoplasmic treatment may protect against early ocular involvement.

Sex and reproduction in the transmission of infectious uveitis

Current data permit only speculations regarding sex differences in the prevalence of infectious uveitis between women and men because uveitis case surveys do not uniformly report gender data. Differences in prevalence that are reported in the literature could relate to simple differences in the number of women and men at risk for infection or to biological differences between men and women. Compared to other types of uveitis, infectious uveitis may be directly related to occupational exposures or sexual behaviors, which differ between women and men, and may mask actual biological differences in susceptibility to ocular manifestations of the infection and its prognosis. In infectious uveitis for which there is no element of sexual transmission and data is available, prevalence of ocular disease is roughly equal between women and men. Women also have a unique relationship with infectious uveitis in their role as mothers. Vertical transmission of infections such as herpes simplex, toxoplasmosis, and cytomegalovirus can produce severe chorioretinitis in neonates.

Congenital toxoplasmosis in a reference center of Paraná, Southern Brazil

This study describes the characteristics of 31 children with congenital toxoplasmosis children admitted to the University Hospital of Londrina, Southern Brazil, from 2000 to 2010. In total, 23 (85.2%) of the mothers received prenatal care but only four (13.0%) were treated for toxoplasmosis. Birth weight was <2500 g in 37.9% of the infants. During the first month of life, physical examination was normal in 34.5%, and for those with clinical signs and symptoms, the main manifestations were hepatomegaly and/or splenomegaly (62.1%), jaundice (13.8%), and microcephaly (6.9%). During ophthalmic examination, 74.2% of the children exhibited injuries, 58.1% chorioretinitis, 32.3% strabismus, 19.4% microphthalmia, and 16.2% vitreitis. Anti-Toxoplasma gondii IgM antibodies were detected in 48.3% of the children. Imaging brain evaluation was normal in 44.8%; brain calcifications, hydrocephaly, or both conditions were observed in 27.6%, 10.3%, and 17.2%, respectively, of the patients. Patients with cerebrospinal fluid protein ≥ 200 mg/dL presented more brain calcifications (p = 0.0325). Other sequelae were visual impairment (55.2% of the cases), developmental delay (31.0%), motor deficit (13.8%), convulsion (27.5%), and attention deficit (10.3%). All patients were treated with sulfadiazine, pyrimethamine, and folinic acid, and 55.2% of them exhibited adverse effects. The results demonstrate the significance of the early diagnosis and treatment of toxoplasmosis during pregnancy to reduce congenital toxoplasmosis and its consequences.

Toxoplasmosis

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

Ocular toxoplasmosis II: clinical features, pathology and management

The term, ocular toxoplasmosis, refers to eye disease related to infection with the parasite, Toxoplasma gondii. Recurrent posterior uveitis is the typical form of this disease, characterized by unilateral, necrotizing retinitis with secondary choroiditis, occurring adjacent to a pigmented retinochoroidal scar and associated with retinal vasculitis and vitritis. Multiple atypical presentations are also described, and severe inflammation is observed in immunocompromised patients. Histopathological correlations demonstrate focal coagulative retinal necrosis, and early in the course of the disease, this inflammation is based in the inner retina. For typical ocular toxoplasmosis, a diagnosis is easily made on clinical examination. In atypical cases, ocular fluid testing to detect parasite DNA by polymerase chain reaction or to determine intraocular production of specific antibody may be extremely helpful for establishing aetiology. Given the high seroprevalence of toxoplasmosis in most communities, serological testing for T. gondii antibodies is generally not useful. Despite a lack of published evidence for effectiveness of current therapies, most ophthalmologists elect to treat patients with ocular toxoplasmosis that reduces or threatens to impact vision. Classic therapy consists of oral pyrimethamine and sulfadiazine, plus systemic corticosteroid. Substantial toxicity of this drug combination has spurred interest in alternative antimicrobials, as well as local forms of drug delivery. At this time, however, no therapeutic approach is curative of ocular toxoplasmosis.

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.

Congenital parasitic infections: a review

This review defines the concepts of maternal-fetal (congenital) and vertical transmissions (mother-to-child) of pathogens and specifies the human parasites susceptible to be congenitally transferred. It highlights the epidemiological features of this transmission mode for the three main congenital parasitic infections due to Toxoplasma gondii, Trypanosoma cruzi and Plasmodium sp. Information on the possible maternal-fetal routes of transmission, the placental responses to infection and timing of parasite transmission are synthesized and compared. The factors susceptible to be involved in parasite transmission and development of congenital parasitic diseases, such as the parasite genotypes, the maternal co-infections and parasitic load, the immunological features of pregnant women and the capacity of some fetuses/neonates to overcome their immunological immaturity to mount an immune response against the transmitted parasites are also discussed and compared. Analysis of clinical data indicates that parasitic congenital infections are often asymptomatic, whereas symptomatic newborns generally display non-specific symptoms. The long-term consequences of congenital infections are also mentioned, such as the imprinting of neonatal immune system and the possible trans-generational transmission. The detection of infection in pregnant women is mainly based on standard serological or parasitological investigations. Amniocentesis and cordocentesis can be used for the detection of some fetal infections. The neonatal infection can be assessed using parasitological, molecular or immunological methods; the place of PCR in such neonatal diagnosis is discussed. When such laboratory diagnosis is not possible at birth or in the first weeks of life, standard serological investigations can also be performed 8-10 months after birth, to avoid detection of maternal transmitted antibodies. The specific aspects of treatment of T. gondii, T. cruzi and Plasmodium congenital infections are mentioned. The possibilities of primary and secondary prophylaxes, as well as the available WHO corresponding recommendations are also presented.

Toxoplasmosis: diagnosis, treatment, and prevention in congenitally exposed infants

Toxoplasmosis is a rare disease caused by the obligate intracellular protozoan parasite, Toxoplasma gondii. Most persons with toxoplasmosis in the United States are asymptomatic, but if a woman is infected during pregnancy, the parasite can cross the placenta and cause congenital toxoplasmosis in the fetus. The severity of congenital toxoplasmosis depends on when in the pregnancy the mother is exposed, but it can cause ocular and central nervous system disease as well as lead to growth failure and hearing and vision abnormalities. Congenital toxoplasmosis is treated with a combination of pyrimethamine, sulfadiazine, and leucovorin. It is important for pediatric nurse practitioners to be aware of the clinical presentation and treatment of congenital toxoplasmosis.

Long-term ocular outcome in congenital toxoplasmosis: a prospective cohort of treated children

OBJECTIVES

Congenital toxoplasmosis remains a public health problem throughout the world. Long-term longitudinal studies are still needed to argument controversial screening and treatment strategies and to enable to accurately counsel parents.

METHODS

We conducted a prospective cohort study over 16 years in Marseilles, France. Seronegative pregnant women underwent monthly serological testing. Children were treated antenatally with rovamycine as soon as maternal infection was detected and with pyrimethamine and sulfadoxine in case of positive Toxoplasma PCR on amniotic fluid. Postnatal treatment with pyrimethamine and sulfadoxine was systematically prescribed for one year and possibly continued at the physician discretion.

RESULTS

127 children were included. 24 children (18.9%) presented ocular lesions causing visual impairment in eight cases. Eleven children (8.7%) presented with ocular lesions at birth, mostly macular. Sixteen children (12.6%) developed ocular lesions during follow-up, mostly peripheral. The first ocular lesion could occur as late as 12 years after birth. No significant risk factor of chorioretinitis was identified including gestational age at infection, type of antenatal treatment and shorter postnatal treatment.

CONCLUSIONS

These results confirm the overall good prognosis of congenital toxoplasmosis in Europe but highlight though a low risk of late ocular manifestation. Chorioretinitis affected 18.9% of children suffering from congenital toxoplasmosis despite antenatal and neonatal screening associated with early treatment. Long-standing follow-up is needed because first lesion can occur as late as 12 years after birth. Late lesions were less often macular but nevertheless caused sometimes visual impairment.

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.

Maternal serologic screening to prevent congenital toxoplasmosis: a decision-analytic economic model

OBJECTIVE

To determine a cost-minimizing option for congenital toxoplasmosis in the United States.

METHODOLOGY/PRINCIPAL FINDINGS

A decision-analytic and cost-minimization model was constructed to compare monthly maternal serological screening, prenatal treatment, and post-natal follow-up and treatment according to the current French (Paris) protocol, versus no systematic screening or perinatal treatment. Costs are based on published estimates of lifetime societal costs of developmental disabilities and current diagnostic and treatment costs. Probabilities are based on published results and clinical practice in the United States and France. One- and two-way sensitivity analyses are used to evaluate robustness of results. Universal monthly maternal screening for congenital toxoplasmosis with follow-up and treatment, following the French protocol, is found to be cost-saving, with savings of $620 per child screened. Results are robust to changes in test costs, value of statistical life, seroprevalence in women of childbearing age, fetal loss due to amniocentesis, and to bivariate analysis of test costs and incidence of primary T. gondii infection in pregnancy. Given the parameters in this model and a maternal screening test cost of $12, screening is cost-saving for rates of congenital infection above 1 per 10,000 live births. If universal testing generates economies of scale in diagnostic tools-lowering test costs to about $2 per test-universal screening is cost-saving at rates of congenital infection well below the lowest reported rates in the United States of 1 per 10,000 live births.

CONCLUSION/SIGNIFICANCE

Universal screening according to the French protocol is cost saving for the US population within broad parameters for costs and probabilities.

Clinical manifestations of ocular toxoplasmosis

Clinical manifestations of ocular toxoplasmosis are reviewed. Findings of congenital and acute acquired ocular toxoplasmosis include retinal scars, white-appearing lesions in the active phase often associated with vitritis. Complications can include fibrous bands, secondary serous or rhegmatogenous retinal detachments, optic neuritis and neuropathy, cataracts, increased intraocular pressure during active infection, and choroidal neovascular membranes. Recurrences in untreated congenital toxoplasmosis occur in teenage years. Manifestations at birth are less severe, and recurrences are fewer in those who were treated promptly early in the course of their disease in utero and in the first year of life. Severe retinal involvement is common at diagnosis of symptomatic congenital toxoplasmosis in the United States and Brazil. Acute acquired infections also may be complicated by toxoplasmic retinochoroiditis, with recurrences most common close to the time of acquisition. Suppressive treatment can reduce recurrent disease.

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.

[Management of congenital toxoplasmosis in France: current data]

Congenital toxoplasmosis is caused by transplacental contamination of the fetus withToxoplasma gondiifollowing maternal primary infection. The risk of mother-to-child transmission depends on the term of pregnancy at the time of maternal infection. The risk is lower than 5% in the first trimester but can reach 90% in the last days of pregnancy. Inversely, however, fetal disease is more severe when contamination occurs early in pregnancy. The French prevention program officially recommends monthly serological screening of susceptible women during pregnancy and information about hygiene and dietary rules. Prenatal diagnosis of congenital toxoplasmosis is based on a combination of examinations: PCR testing for the parasite in amniotic fluid, mouse inoculation, fetal ultrasonography, and magnetic resonance imaging. Neonatal screening consists of PCR of the placenta, mouse inoculation, detection of specific IgM and IgA in the newborn, ocular fundus examinations by indirect ophthalmoscopy, and transfontanellar ultrasonography. As soon as maternal infection is suspected, preventive treatment with spiramycin begins; the treatment is changed to a combination of pyrimethamine-sulfonamide if fetal infection is proved. Some teams are using this combination as first-line treatment after 30 weeks of gestation, without performing amniocentesis. Recent European multicenter studies raise questions about the effectiveness of prenatal treatment on mother-to-child transmission and on the reduction in the number and severity of fetal sequelae. A randomized controlled trial is required to prove the efficacy of prenatal treatment in general and of specific drugs, in particular. As soon as infection is confirmed, infected children are treated with the pyrimethamine-sulfonamide combination for 12 to 24 months. Recent multicenter studies show that postnatal treatment does not prevent ocular lesions: 5% of treated children had choroiditis lesions at birth, 20% at 5 years, and 30% at 8 years of age. Furthermore no consensus exists about the duration of postnatal treatment (3 months in Denmark versus 12 months in France). A multicenter randomized controlled trial is necessary to assess the efficacy of postnatal treatment and determine its duration. A surveillance system was set up in 2007 by the National Reference Center for Toxoplasmosis to determine the perinatal burden of this infection and to assess the national policy.

Why prevent, diagnose and treat congenital toxoplasmosis?

Evidence that prevention, diagnosis and treatment of toxoplasmosis is beneficial developed as follows: anti-parasitic agents abrogate Toxoplasma gondii tachyzoite growth, preventing destruction of infected, cultured, mammalian cells and cure active infections in experimental animals, including primates. They treat active infections in persons who are immune-compromised, limit destruction of retina by replicating parasites and thereby treat ocular toxoplasmosis and treat active infection in the fetus and infant. Outcomes of untreated congenital toxoplasmosis include adverse ocular and neurologic sequelae described in different countries and decades. Better outcomes are associated with treatment of infected infants throughout their first year of life. Shorter intervals between diagnosis and treatment in utero improve outcomes. A French approach for diagnosis and treatment of congenital toxoplasmosis in the fetus and infant can prevent toxoplasmosis and limit adverse sequelae. In addition, new data demonstrate that this French approach results in favorable outcomes with some early gestation infections. A standardized approach to diagnosis and treatment during gestation has not yet been applied generally in the USA. Nonetheless, a small, similar experience confirms that this French approach is feasible, safe, and results in favorable outcomes in the National Collaborative Chicago-based Congenital Toxoplasmosis Study cohort. Prompt diagnosis, prevention and treatment reduce adverse sequelae of congenital toxoplasmosis.

Longitudinal study of new eye lesions in children with toxoplasmosis who were not treated during the first year of life

PURPOSE

To determine the incidence of new chorioretinal lesions in children with toxoplasmosis diagnosed after, and therefore not treated during, their first year.

DESIGN

Prospective longitudinal cohort study.

METHODS

Thirty-eight children were evaluated in Chicago between 1981 and 2005 for new chorioretinal lesions. Thirty-eight children and mothers had serum IgG antibody to Toxoplasma gondii.

RESULTS

Twenty-eight of 38 children had one of the following: diagnosis with serum antibody to T. gondii indicative of chronic infection at age 24 months, central nervous system calcifications, hydrocephalus, illness compatible with congenital toxoplasmosis perinatally but not diagnosed at that time. Twenty-five returned for follow-up during 1981 to 2005. Their mean (range) age at last exam was 10.9 +/- 5.7 (range, 3.5 to 27.2) years and mean follow-up was 5.7 +/- 2.9 years. Eighteen (72%) children developed at least one new lesion. Thirteen (52%) had new central lesions, 11 (44%) had new peripheral lesions, and six (24%) had both. Thirteen (52%) had new lesions diagnosed at age > or =10 years. New lesions were found at more than one visit in four (22%), and bilateral new lesions developed in seven (39%) of 18 children who developed new lesions. Of 10 additional children with eye findings and serologic tests indicative of chronic infection, six returned for follow-up, four (67%) developing new lesions at > or =10 years of age.

CONCLUSIONS

More than 70% developed new chorioretinal lesions. New lesions were commonly diagnosed after the first decade of life.