Zika Virus and Pregnancy: Association between Acute Infection and Microcephaly in Newborns in the State of Rio de Janeiro, Brazil.

Introduction Aim of the study was to evaluate the association between microcephaly and acute infection with Zika virus (ZIKV) in pregnant women in the state of Rio de Janeiro, Brazil. Infection was confirmed by laboratory testing. Materials and Methods A cross-sectional retrospective study of pregnant women with symptoms occurring between 2015 and 2016 suggestive of acute ZIKV infection was carried out, with confirmation of infection done by blood or urine RT-PCR. The relative proportions of categorical variables were calculated for two distinct groups: pregnant women whose newborns had microcephaly and pregnant women who gave birth to infants without microcephaly. Confidence intervals with a 95% level of agreement were estimated for the relative ratios. Results A total of 1609 pregnant women with a mean age of 26.4 ± 6.5 years were evaluated. As regards the time of acute infection, 19.6% (316) of cases occurred in the first trimester of pregnancy. Nineteen (76%) of the 25 cases with microcephaly (1.5%) were associated with an infection contracted in the first trimester of pregnancy (p < 0.001, OR = 13.7, 95% CI: 5.6 - 37.7). 48% (12/25) of the newborns with microcephaly had a birth weight of < 2500 grams, while only 7% (116/1597) of the group of newborns without microcephaly had a similarly low birth weight (p < 0.001, OR = 11.7, 95% CI: 5.2 - 26.2). Logistic regression showed that a birth weight of < 2500 g (OR = 12.54) and ZIKV infection in the first trimester of pregnancy (OR = 14.05) were associated with microcephaly (area under ROC curve = 0.86). Conclusion Acute ZIKV infection in the first trimester of pregnancy and low birth weight are associated with microcephaly.

Zika virus and pregnancy in Brazil: What happened?

The recent epidemic of Zika virus (ZIKV) infection in Central and South America is one of the most serious global public health emergencies since the Ebola outbreak in West Africa. In Brazil, especially in the north, northeast, and southeast parts of the country, the ZIKV outbreak is a cause of concern for pregnant women because ZIKV intrauterine infection has been found to be associated with multiple brain malformations and microcephaly. In Brazil, the number of newborns with confirmed microcephaly per year recorded during the ZIKV outbreak, has been approximately 15 times greater than previously reported. Considering that the infection is self-limiting and symptomatic, it is usually diagnosed at the time of routine prenatal scan, especially in the third trimester. In other cases, the disease is detected after childbirth through neuroimaging. This study provides an insight into the history and evolution of ZIKV in Brazil, including current knowledge concerning the transmission, diagnosis, and pathogenesis of the infection. In addition, this review describes the pre- and postnatal neuroimaging findings obtained using ultrasound, magnetic resonance imaging, and computed tomography.