Elsevier

Ophthalmology

Volume 116, Issue 11, November 2009, Pages 2199-2205.e1
Ophthalmology

Original article
Congenital Toxoplasmosis in Southeastern Brazil: Results of Early Ophthalmologic Examination of a Large Cohort of Neonates

Presented in part at the III International Congress on Congenital Toxoplasmosis, May 13–16, 2007, Montenegro, Colombia, and at the 9th Congress of the International Ocular Inflammation Society, September 17–20, 2007, Paris, France.
https://doi.org/10.1016/j.ophtha.2009.04.042Get rights and content

Objective

To report results of early ophthalmologic examinations in a large cohort of newborns with congenital toxoplasmosis (CT) after neonatal screening.

Design

Cross-sectional analysis of a cohort.

Participants

A total of 178 newborns with confirmed CT from 146,307 screened babies (95% of live births) from Minas Gerais state, southeastern Brazil.

Methods

From November 2006 to May 2007, newborns underwent neonatal screening by immunoglobulin (Ig)M capture of dried blood samples. On all positive or suspected cases, confirmative serology was performed on babies and their mothers. Congenital toxoplasmosis was confirmed in newborns who had IgM and/or IgA and IgG, or IgG associated with suggestive ocular lesions (with IgM and IgG in the mother). Ophthalmologic evaluation consisted of indirect ophthalmoscopy with a lid speculum. Pediatric examination and radiologic studies of the central nervous system were also performed. In selected cases, biomicroscopy of the anterior segment, fundus photographs, or ultrasonography (B-scan) was performed.

Main Outcome Measures

Prevalence of retinochoroidal lesions, either cicatricial or active, and their location and associated findings, such as vascular sheathing, hemorrhage, vitreous opacities, and retinal detachment, were evaluated. The occurrence of cataract, microphthalmia, microcephaly, intracranial calcification, and hydrocephalus was also recorded.

Results

Of 146,307 neonates screened, 190 had CT, yielding a prevalence of 1 in 770 live births, of whom 178 (93.7%) underwent standardized ophthalmologic examination at an average age of 55.6±16.6 days. Of these 178 infants, 142 (79.8%) had retinochoroidal lesions consistent with CT in at least 1 eye. Bilateral involvement was noted in 113 patients (63.5%). Macular involvement was seen in 165 eyes (46.3%) of 111 patients (62.4%). Active lesions were observed in 142 eyes (39.9%) of 85 patients (47.8%). These lesions were located in the macula of 75 eyes (21.1%) and were associated with retinal vascular sheathing in 44 eyes (12.4%).

Conclusions

A high prevalence of CT was encountered (1/770) with high rates of early retinochoroidal involvement (∼80%) and many active lesions (in ∼50%), indicating a possibly more severe ocular involvement by CT in Brazil than in other parts of the world. The hypotheses of higher parasite virulence and increased individual susceptibility are being currently investigated.

Financial Disclosure(s)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Section snippets

Materials and Methods

This study is part of a prospective investigation on neonatal screening for CT in the Brazilian state of MG. It is being carried out by a multidisciplinary research group (UFMG-Congenital Toxoplasmosis Brazilian Group) under the coordination of one of the authors (GMQ-A). The study protocol followed the precepts of the Declaration of Helsinki and was approved by the Ethics Committee at our institution (Ethics Commitee at Universidade Federal de Minas Gerais).

From November 1, 2006, to May 31,

Results

A total of 146,307 newborns were screened during the 6-month period (November 1, 2006 to May 31, 2007), corresponding to approximately 95% of the live births in the state of MG during those months. Of these screened babies, 235 had suspected CT and, along with their mothers, underwent confirmative serology. Infection was confirmed in 190 cases, corresponding to a prevalence of 1 in 770 liveborn infants.

Among the 45 cases that were not confirmed, 35 (77.8%) had the infection ruled out because

Discussion

The prevalence of CT (1/770 live births) is higher in the present study than in most other reported series in the rest of the world19, 20, 21, 22, 23 and in Brazil.13, 14, 15, 16, 17 These few published reports on the prevalence of CT in Brazil13, 14, 15, 16, 17 have involved limited geographic areas and had selection and referral bias that may limit interpretation and extrapolation of the resultant data. In contrast, our study had coverage of approximately 95% of liveborn infants in a large

Study Limitations

A neonatal screening strategy using detection of IgM may underestimate the prevalence of CT by missing fetal losses and perinatal/early neonatal deaths (which are rare), as well as by false-negative cases, which may be reflected by the smaller number of newborns who were infected in the first gestational trimester45, 46 (and who may ultimately have more severe disease). However, neonatal screening offers the advantages of lower cost and relative simplicity, and thereby allows the study of large

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    • The congenital toxoplasmosis burden in Brazil: Systematic review and meta-analysis

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      The estimated global incidence of congenital toxoplasmosis (CT) is of 190,100 annual cases; this corresponds to an incidence rate of approximately 1.5 cases in 1,000 live births (Torgerson and Mastroiacovo, 2013). In Brazil, the reported prevalence ranges from 0.3 cases to 3.4/1,000 live births (da Silva et al., 2015), and studies have estimated that approximately 35% of children had neurological disease including hydrocephalus, microcephaly and mental retardation; 80% had ocular lesions, and in one report 40% of children had hearing loss (Andrade et al., 2008; Carellos et al., 2017; Vasconcelos-Santos et al., 2009). Brazil is a vast country with remarkable differences in socioeconomic and health care conditions.

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    Manuscript no. 2008-1484.

    Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

    Financial support provided by Secretaria do Estado de Saúde de Minas Gerais, Brazil.

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