Two Infants with Presumed Congenital Zika Syndrome, Brownsville, Texas, USA, 2016–2017

Since 2007, Zika virus has spread through the Pacific Islands and the Americas. Beginning in 2016, women in Brownsville, Texas, USA, were identified as possibly being exposed to Zika virus during pregnancy. We identified 18 pregnant women during 2016-2017 who had supportive serologic or molecular test results indicating Zika virus or flavivirus infection. Two infants were evaluated for congenital Zika syndrome after identification of prenatal microcephaly. Despite standard of care testing of mothers and neonates, comparative results were unreliable for mothers and infants, which highlights the need for clinical and epidemiologic evidence for an accurate diagnosis. A high index of suspicion for congenital Zika syndrome for at-risk populations is useful because of current limitations of testing.