Neonatal surveillance for congenital Zika infection during the 2016 microcephaly outbreak in Salvador, Brazil: Zika virus detection in asymptomatic newborns
João Vitor Oliveira, Tereza Cristina Xavier Carvalho, Marta Giovanetti, Jaqueline Góes de Jesus, Cleiton Silva Santos, Lorena B. Pessoa, Cláudio F.Q. Magalhães Filho, Jéssica da Costa Lima, Daniel Augusto Carvalho, Eduardo Manoel Figueiredo, Ana Carolina Biron, Daiana Carlos dos Santos, Paloma Viana, Alan Oliveira Duarte, Rosana Pessoa, Gloryane Bessa Souza, Juan Ignácio Calcagno, Fernanda W. M. Lima, Luiz C.J. Alcantara, Isadora Cristina de Siqueira
Abstract
OBJECTIVE: To identify newborns with congenital Zika infection (CZI) at a maternity hospital in Salvador, Brazil, during the 2016 microcephaly outbreak. METHODS: A prospective study enrolled microcephalic and normocephalic newborns with suspected CZI between January and December 2016. Serology (immunoglobulins IgM and IgG) and quantitative reverse transcriptase polymerase chain reaction (RT-qPCR) for the Zika virus were performed. Demographic and clinical characteristics of newborns with and without microcephaly were compared. RESULTS: Of the 151 newborns enrolled, 32 (21.2%) were classified as microcephalic. The majority of these cases were born between January and May 2016. IgM and IgG Zika virus antibodies were detected in 5 (23.8%) and 17 (80.9%) microcephalic newborn blood samples, respectively. Six (24%) microcephalic newborns tested positive for Zika virus by RT-qPCR in urine or placenta samples. Thirteen (11.8%) normocephalic newborns also tested positive for Zika virus by PCR in urine, plasma, or placenta samples, while IgM antibodies against Zika were detected in 4 (4.2%) others. CONCLUSIONS: Identification of 17 normocephalic CZI cases, confirmed by IgM serology or RT-qPCR for Zika virus, provides evidence that CZI can present asymptomatically at birth. This finding highlights the need for prenatal and neonatal screening for Zika virus in endemic regions.