In a sample of infants born with microcephaly and a presumed diagnosis of congenital Zika virus, about one-third were found to have vision-threatening eye abnormalities, according to researchers working in a Zika hot spot in Brazil.
The group, led by Dr. Bruno de Paula Freitas of the Hospital Geral Roberto Santos, in Salvador, Brazil, evaluated 29 infants with microcephaly born at a single hospital in December following suspected maternal infection with the mosquito-borne Zika virus. In a paper published online Feb 9., Dr. de Paula Freitas and his colleagues reported eye abnormalities in 10 of these children (34.5%) (JAMA Ophthalmol. doi:10.1001/jamaophthalmol.2016.0267.).
Brazil first reported an outbreak of Zika virus infections in April 2015, followed months later by a spike in the number of infants born with microcephaly, a birth defect defined by a cephalic circumference of 32 cm or less in newborns. The most common ocular abnormalities seen in the cohort of affected infants were pigment mottling of the retina and chorioretinal atrophy (11 of 17 abnormal eyes); optic nerve abnormalities (8 eyes); and iris coloboma (affecting 2 eyes in one infant).
While a previous study of a Zika virus outbreak in Micronesia found conjunctivitis among infected individuals, none of the mothers of the current cohort of infants disclosed having had conjunctivitis. Altogether 23 of the mothers (79%) reported having had any symptoms of Zika virus infection during pregnancy.
Dr. de Paula Freitas and his colleagues acknowledged that their results were limited by a small sample size and single-site study design. However, the investigators noted, the findings suggest the possibility “that even oligosymptomatic or asymptomatic pregnant patients presumably infected [with Zika virus] may have microcephalic newborns with ophthalmoscopic lesions” and those newborns should be routinely evaluated for ocular symptoms.
An important question that requires further investigation, they noted, is whether newborns without microcephaly, but whose mothers may have been infected with the Zika virus, should be screened to identify possible ocular lesions.
Funding for the study came from Hospital Geral Roberto Santos, Federal University of São Paulo, Vision Institute, and Conselho Nacional de Desenvolvimento Científico e Tecnológico in Brasília, Brazil. The authors reported having no financial disclosures.