Abstract
Recent data in a nonhuman primate model showed that infants postnatally infected with Zika virus (ZIKV) were acutely susceptible to high viremia and neurological damage, suggesting the window of vulnerability extends beyond gestation. In this pilot study, we addressed the susceptibility of two infant rhesus macaques born healthy to dams infected with Zika virus during pregnancy. Passively acquired neutralizing antibody titers dropped below detection limits between 2 and 3 months of age, while binding antibodies remained detectable until viral infection at 5 months. Acute serum viremia was comparatively lower than adults infected with the same Brazilian isolate of ZIKV (n = 11 pregnant females, 4 males, and 4 non-pregnant females). Virus was never detected in cerebrospinal fluid nor in neural tissues at necropsy two weeks after infection. However, viral RNA was detected in lymph nodes, confirming some tissue dissemination. Though protection was not absolute and our study lacks an important comparison with postnatally infected infants born to naïve dams, our data suggest infants born healthy to infected mothers may harbor a modest but important level of protection from postnatally acquired ZIKV for several months after birth, an encouraging result given the potentially severe infection outcomes of this population.
Highlights
Human brain development continues well after birth[31] so it stands to reason that the risk of Zika virus (ZIKV) associated neurological disease may extend for an unknown period of time after birth
Nonhuman primate studies suggest that infants may remain susceptible to ZIKV induced disease even if infected after birth[32], but the frequency and disease severity postnatal ZIKV infections in human infants remains to be fully examined[34,35]
Given the high incidence of ZIKV in several countries during the height of the outbreak[36], the relative abundance of the most competent vector for ZIKV transmission, the mosquito Aedes aegypti, in urban environments (Centers for Disease Control [CDC], 2017), it’s likely that many infants born healthy to infected mothers are themselves exposed to the virus via mosquito bite after birth. It is not clear if passively acquired maternal antibodies against ZIKV can offer some level of protection and for what period of time after birth
Summary
Human brain development continues well after birth[31] so it stands to reason that the risk of ZIKV associated neurological disease may extend for an unknown period of time after birth. Since not all infants exhibit detectable ZIKV disease when born to infected mothers, it remains unclear whether these infants remain uninfected and/or unaffected due to pre-existing passively acquired maternal antibodies, if they mount their own de novo anti-ZIKV immune responses in utero or soon after birth, or if infection can be limited and apathogenic for an unknown reason. Addressing these issues will be key to addressing the susceptibility of newborns to postnatal ZIKV infection in areas with endemic for ZIKV transmission. These data suggest that being born to a ZIKV infected mother may confer a small but important level of immunity to postnatal infection
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
