A recent study published in JAMA Pediatrics evaluated findings from eye examinations in infants with potential for Zika virus exposure to determine whether screening eye examinations are necessary for all infants with possible exposure to Zika.
The zika virus caught the attention of the world when a large outbreak occurred in Brazil approximately two years ago. Spread by mosquitoes, sexual contact, infected blood, and from mother to infant during pregnancy, the outbreak resulted in a high number of microcephaly cases, an abnormal smallness of the head that is linked with incomplete brain development. While microcephaly is often the most remarkable characteristic of this infection, it is not a necessary finding when it comes to the diagnosis of the congenital Zika virus infection. In fact, there have been cases where seemingly asymptomatic infants have shown eye, brain, or other central nervous system abnormalities upon imaging or subsequent examinations.
Current guidelines recommend screening eye examinations for infants with microcephaly or laboratory-confirmed Zika virus infection. However, a recent study published in JAMA Pediatrics presents data that suggests otherwise, arguing that all infants who have potentially been exposed to Zika virus should undergo screening eye examinations.
Performed from January through October 2016, this descriptive case series examined infants from birth to one year of age. The multidisciplinary medical team in charge of these examinations included, most notably, a pediatric ophthalmologist from the Fernandes Figueira Institute—a referral center for high-risk pregnancies and infectious diseases in children in Rio de Janeiro, Brazil. Mother-infant pairs from around the city who presented with suspected Zika virus infection during pregnancy were referred to this institution and underwent tests to determine whether they were infected with the virus. Eye and other central nervous system abnormalities, in addition to microcephaly status, were recorded during the data collection period.
The results showed that of the 112 infants born to mothers with confirmed Zika virus infection, 21.4% had eye abnormalities. Furthermore, 41.7% of infants with abnormal eye examination findings did not have microcephaly and 33.3% did not have any central nervous system findings. In other words, eye abnormalities may be the only initial finding of congenital Zika virus infection. However, it is important to keep in mind that due to the lack of a control group, one cannot attribute—with absolute certainty—all of these abnormal eye findings to Zika virus; for instance, 3 infants exhibited findings of retinal hemorrhage only, possibly stemming from birth trauma.
Overall, the researchers suggest performing eye examinations on all infants with potential Zika virus exposure—not just those with microcephaly and laboratory-confirmed infections. Hopefully, implementation of this screening protocol may result in earlier diagnosis of congenital Zika virus infection in seemingly asymptomatic infants.
Written by Rebecca Yu
Zin, A. A., Tsui, I., Rossetto, J., Vasconcelos, Z., Adachi, K., Valderramos, S., … & Aibe, M. S. (2017). Screening Criteria for Ophthalmic Manifestations of Congenital Zika Virus Infection. JAMA Pediatrics.