Clinical Infectious Diseases, January 8, 2019
Jose Paulo Pereira, Jr Melanie M Maykin, Zilton Vasconcelos, Elyzabeth Avvad-Portari, Andrea A Zin, Irena Tsui, Patricia Brasil, Karin Nielsen-Saines, Maria E Moreira, Stephanie L Gaw
The identification of Zika virus (ZIKV) from the amniotic fluid of 2 fetuses with severe central nervous system (CNS) abnormalities in 2016 was the first evidence of vertical transmission of ZIKV. ZIKV has since been established as the etiology of congenital Zika syndrome (CZS), characterized in its most severe form by microcephaly and severe CNS malformations, with rates of adverse pregnancy outcome exceeding 40% in some studies. Prenatal diagnosis of CZS informs management of the pregnancy and care of the ZIKV-exposed infant. However, the optimal method of prenatal screening and diagnosis of ZIKV infection remains undetermined. Testing is complicated by the asymptomatic course of most infections, the narrow window of viral RNA detection in maternal serum and/or urine, limitations in maternal serologic testing due to delayed sero-conversion, and false-positive results from cross-reactivity with other flaviviruses. Amniocentesis, the gold standard for prenatal diagnosis of vertical transmission in other infections, has not been routinely recommended in cases of suspected CZS, due to the invasive nature of the test (which carries a small risk of pregnancy complications), the limited data available to guide the timing of testing and interpretation of results, and limited therapeutic options. Available data on the performance of ZIKV detection in amniotic fluid have been limited to isolated case reports and small case series of confirmed CZS that have reported a total of 27 cases.