Contracted through the bite of an infected mosquito or through sexual or other modes of transmission, Zika virus (ZIKV) infection can be prenatally passed from mother to fetus.¹ The virus was first identified in the region of the Americas in early 2015, when local transmission was reported in Brazil.² Six months later, a notable increase in the number of infants with congenital microcephaly was observed in northeast Brazil.^3,4 Clinical, epidemiologic, and laboratory evidence led investigators to conclude that intrauterine ZIKV infection was a cause of microcephaly and serious brain anomalies.^5-7 However, as with other newly recognized teratogens, these features likely represent a portion of a broader spectrum.

Congenital Zika virus infection can cause microcephaly and severe brain abnormalities (1). Congenital Zika syndrome comprises a spectrum of clinical features (2); however, as is the case with most newly recognized teratogens, the earliest documented clinical presentation is expected to be the most severe. Initial descriptions of the effects of in utero Zika virus infection centered prominently on the finding of congenital microcephaly (3). To assess the possibility of clinical presentations that do not include congenital microcephaly, a retrospective assessment of 13 infants from the Brazilian states of Pernambuco and Ceará with normal head size at birth and laboratory evidence of congenital Zika virus infection was conducted. All infants had brain abnormalities on neuroimaging consistent with congenital Zika syndrome, including decreased brain volume, ventriculomegaly, subcortical calcifications, and cortical malformations. The earliest evaluation occurred on the second day of life. Among all infants, head growth was documented to have decelerated as early as 5 months of age, and 11 infants had microcephaly. These findings provide evidence that among infants with prenatal exposure to Zika virus, the absence of microcephaly at birth does not exclude congenital Zika virus infection or the presence of Zika-related brain and other abnormalities. These findings support the recommendation for comprehensive medical and developmental follow-up of infants exposed to Zika virus prenatally. Early neuroimaging might identify brain abnormalities related to congenital Zika infection even among infants with a normal head circumference (4).

In 2015, a twenty-fold increase in the prevalence of microcephaly in Brazil was reported, and the Ministry of Health associated this abnormal prevalence with the maternal-fetal Zika virus (ZIKV) transmission. We assessed the ophthalmological findings of ten mothers and their infants that had been clinically diagnosed with ZIKV-related microcephaly and presented ocular abnormalities, born from May to December 2015. Seven mothers (70.0%) referred symptoms during pregnancy (malaise, rash and arthralgia), of which six (85.7%) were in the first trimester. At the time of exam, no ophthalmological abnormalities were identified in the mothers and they did not report ocular symptoms during pregnancy. Serology was negative in all infants for Toxoplasmosis, Rubella, Cytomegalovirus, Syphilis and Human Immunodeficiency Viruses. Ocular findings included macular alterations (gross pigment mottling and/or chorioretinal atrophy) in fifteen eyes (75.0%), and optic nerve abnormalities (hypoplasia with double-ring sign, pallor, and/or increased cup-to-disk ratio) in nine eyes (45.0%). Patients presented normal anterior segment and important macular and optic nerve abnormalities. Further studies will assess the visual significance of these alterations.

Objective To describe the clinical, radiological, and electromyographic features in a series of children with joint contractures (arthrogryposis) associated with congenital infection presumably caused by Zika virus. Design Retrospective case series study. Setting Association for Assistance of Disabled Children, Pernambuco state, Brazil. Participants Seven children with arthrogryposis and a diagnosis of congenital infection presumably caused by Zika virus during the Brazilian microcephaly epidemic. Main outcome measures Main clinical, radiological, and electromyographic findings, and likely correlation between clinical and primary neurological abnormalities. Results The brain images of all seven children were characteristic of congenital infection and arthrogryposis. Two children tested positive for IgM to Zika virus in the cerebrospinal fluid. Arthrogryposis was present in the arms and legs of six children (86%) and the legs of one child (14%). Hip radiographs showed bilateral dislocation in seven children, subluxation of the knee associated with genu valgus in three children (43%), which was bilateral in two (29%). All the children underwent high definition ultrasonography of the joints, and there was no evidence of abnormalities. Moderate signs of remodeling of the motor units and a reduced recruitment pattern were found on needle electromyography (monopolar). Five of the children underwent brain computed tomography (CT) and magnetic resonance imaging (MRI) and the remaining two CT only. All presented malformations of cortical development, calcifications predominantly in the cortex and subcortical white matter (especially in the junction between the cortex and white matter), reduction in brain volume, ventriculomegaly, and hypoplasia of the brainstem and cerebellum. MRI of the spine in four children showed apparent thinning of the cord and reduced ventral roots. Conclusions Congenital Zika syndrome should be added to the differential diagnosis of congenital infections and arthrogryposis. The arthrogryposis was unrelated to the abnormalities of the joints themselves, but was possibly of neurogenic origin, with chronic involvement of central and peripheral motor neurones leading to deformities as a result of fixed postures in utero. Based on the neurophysiological observations, we suggest two possible mechanisms: tropism of neurones, with involvement of peripheral and central motor neurones, or a relation with vascular disorders.

Research from JAMA Ophthalmology — Risk Factors Associated With the Ophthalmoscopic Findings Identified in Infants With Presumed Zika Virus Congenital Infection