Zika virus (ZIKV) infection during pregnancy causes congenital abnormalities, including microcephaly. However, rates vary widely, and the contributing risk factors remain unclear. We examined the serum antibody response to ZIKV and other flaviviruses in Brazilian women giving birth during the 2015–2016 outbreak. Infected pregnancies with intermediate or higher ZIKV antibody enhancement titers were at increased risk to give birth to microcephalic infants compared with those with lower titers (P < 0.0001). Similarly, analysis of ZIKV-infected pregnant macaques revealed that fetal brain damage was more frequent in mothers with higher enhancement titers. Thus, features of the maternal antibodies are associated with and may contribute to the genesis of ZIKV-associated microcephaly.

SUMMARYThe most frequent pathway of vertical transmission of HTLV-I is breast-feeding, however bottle fed children may also become infected in a frequency varying from 4 to 14%. In these children the most probable routes of infection are transplacental or contamination in the birth canal.Forty-one bottle-fed children of HTLV-I seropositive mothers in ages varying from three to 39 months (average age of 11 months) were submitted to nested polymerase chain reaction analysis (pol and tax genes). 81.5% of the children were born by an elective cesarean section.No case of infection was detected. The absence of HTLV-I infection in these cases indicates that transmission by transplacental route may be very infrequent.

Despite the decreasing rates in Brazil from 2005 to 2010, early neonatal mortality rates associated with perinatal asphyxia in infants in the better spectrum of birth weight and without congenital malformations are still high, and meconium aspiration syndrome plays a major role.

Breastfeeding seems to be a safe feeding practice for infants born at term and small for gestational age, showing no association with deleterious short-term outcomes. Breastfeeding stimulation in these populations seems to be a way of preventing the health problems associated with the high risk of chronic noncommunicable diseases and obesity.

Reduction of birth asphyxia in very low birth weight infants is essential to reducing neonatal mortality in Brazil.