Postnatal Zika Virus Research Articles

Postnatal Zika and Dengue Infection and their Effects on Neurodevelopment Among Children Living in Rural Guatemala.

Prenatal Zika virus (ZIKV) infection leads to microcephaly and adverse neurodevelopment. The effects of postnatal ZIKV infection on the developing brain are unknown. We assessed the neurodevelopmental outcomes of children exposed postnatally during the ZIKV epidemic. A prospective study enrolled infants 0-3 months of age and their mothers, and children 1.5-3.5 years of age in rural Guatemala from 2017 and were followed for 12 months until 2019. Neurodevelopment was evaluated using the Mullen Scales of Early Learning (MSEL). ZIKV and dengue virus (DENV) infections were identified by polymerase chain reaction (PCR) using active surveillance. Serological analyses, stratified by age group flavivirus serostatus at enrollment, were conducted using a focus reduction neutralization test. Of 1371 enrolled participants, 1187 (86.6%) completed the study. No PCR-confirmed ZIKV infections were identified during the study period. One-third of 1.5-3.5-year-old children were ZIKV-seropositive at enrollment (likely postnatal infection). Twenty participants (5.8%) tested positive for DENV by PCR (11 infants, 5 children and 4 mothers); 15 (75%) were DENV-3 infections and 5 were DENV-2. The incidence of DENV infection in infants was 2.6%. No significant differences in MSEL scores were found between infants born seropositive versus seronegative for ZIKV or DENV. DENV seropositivity at enrollment in 1.5-5-year-old children was associated with lower MSEL scores for fine motor, visual reception and language, and microcephaly at 12 months versus seronegative children (all P < 0.05). Postnatal ZIKV infection in children from rural Guatemala was not associated with worse neurodevelopmental outcomes. DENV seropositivity was associated with a higher risk of microcephaly in infants and worse neurodevelopmental outcomes in children.

Postnatal Zika virus infection leads to morphological and cellular alterations within the neurogenic niche.

The Zika virus received significant attention in 2016, following a declaration by the World Health Organization of an epidemic in the Americas, in which infections were associated with microcephaly. Indeed, prenatal Zika virus infection is detrimental to fetal neural stem cells and can cause premature cell loss and neurodevelopmental abnormalities in newborn infants, collectively described as congenital Zika syndrome. Contrastingly, much less is known about how neonatal infection affects the development of the newborn nervous system. Here, we investigated the development of the dentate gyrus of wild-type mice following intracranial injection of the virus at birth (postnatal day 0). Through this approach, we found that Zika virus infection affected the development of neurogenic regions within the dentate gyrus and caused reactive gliosis, cell death and a decrease in cell proliferation. Such infection also altered volumetric features of the postnatal dentate gyrus. Thus, we found that Zika virus exposure to newborn mice is detrimental to the subgranular zone of the dentate gyrus. These observations offer insight into the cellular mechanisms that underlie the neurological features of congenital Zika syndrome in children.

Treatment with sofosbuvir attenuates the adverse neurodevelopmental consequences of Zika virus infection in infant rhesus macaques

Zika virus (ZIKV) infection during infancy in a rhesus macaque (RM) model negatively impacts brain development resulting in long-term behavioral alterations. The current study investigated whether postexposure prophylaxis could alleviate these negative neurodevelopmental consequences. Three RM infants received a 14-day course of sofosbuvir (SOF; 15 mg/kg p.o.) treatment starting at 3 days post-infection with a Puerto Rican strain of ZIKV (PRVABC59) and were then monitored longitudinally for one year. In contrast to ZIKV-infected infant RMs who did not receive SOF, postexposure SOF treatment mitigated the neurodevelopmental, behavioral and cognitive changes seen after postnatal ZIKV infection even while not accelerating viral clearance from the blood. These data suggest that antiviral treatment may help ameliorate some, but not all, of the neurodevelopmental abnormalities associated with early postnatal ZIKV infection.

Neurotoxic properties of the Zika virus envelope protein

Prenatal Zika virus (ZIKV) infection is a serious global concern as it can lead to brain injury and many serious birth defects, collectively known as congenital Zika syndrome. Brain injury likely results from viral mediated toxicity in neural progenitor cells. Additionally, postnatal ZIKV infections have been linked to neurological complications, yet the mechanisms driving these manifestations are not well understood. Existing data suggest that the ZIKV envelope protein can persist in the central nervous system for extended periods of time, but it is unknown if this protein can independently contribute to neuronal toxicity. Here we find that the ZIKV envelope protein is neurotoxic, leading to overexpression of poly adenosine diphosphate -ribose polymerase 1, which can induce parthanatos. Together, these data suggest that neuronal toxicity resulting from the envelope protein may contribute to the pathogenesis of post-natal ZIKV-related neurologic complications.

Challenges and lessons learned from the rapid operationalization of a prospective cohort to study the natural history and neurodevelopmental outcomes of postnatal Zika virus infection among infants and children in rural Guatemala.

During the course of the 2015-2017 outbreak of Zika virus (ZIKV) in the Americas, the emerging virus was recognized as a congenital infection that could damage the developing brain. As the Latin American ZIKV outbreak advanced, the scientific and public health community questioned if this newly recognized neurotropic flavivirus could affect the developing brain of infants and young children infected after birth. We report here the study design, methods and the challenges and lessons learned from the rapid operationalization of a prospective natural history cohort study aimed at evaluating the potential neurological and neurodevelopmental effects of postnatal ZIKV infection in infants and young children, which had become epidemic in Central America. This study enrolled a cohort of 500 mothers and their infants, along with nearly 400 children 1.5-3.5 years of age who were born during the initial phase of the ZIKV epidemic in a rural area of Guatemala. Our solutions and lessons learned while tackling real-life challenges may serve as a guide to other researchers carrying out studies of emerging infectious diseases of public health priority in resource-constrained settings.

Clinical and Preclinical Evidence for Adverse Neurodevelopment after Postnatal Zika Virus Infection.

Although the Zika virus (ZIKV) typically causes mild or no symptoms in adults, during the 2015−2016 outbreak, ZIKV infection in pregnancy resulted in a spectrum of diseases in infants, including birth defects and neurodevelopmental disorders identified in childhood. While intense clinical and basic science research has focused on the neurodevelopmental outcomes of prenatal ZIKV infection, less is known about the consequences of infection during early life. Considering the neurotropism of ZIKV and the rapidly-developing postnatal brain, it is important to understand how infection during infancy may disrupt neurodevelopment. This paper reviews the current knowledge regarding early postnatal ZIKV infection. Emerging clinical evidence supports the hypothesis that ZIKV infection during infancy can result in negative neurologic consequences. However, clinical data regarding postnatal ZIKV infection in children are limited; as such, animal models play an important role in understanding the potential complications of ZIKV infection related to the vulnerable developing brain. Preclinical data provide insight into the potential behavioral, cognitive, and motor domains that clinical studies should examine in pediatric populations exposed to ZIKV during infancy.

757. Association between cumulative febrile, respiratory and diarrheal illness in the first year of life and neurodevelopmental and growth outcomes among a cohort of children in rural Guatemala

BackgroundRecurrent infections are associated with neurodevelopmental (ND) delay in infants, but the primary drivers are poorly understood. Leveraging an infant cohort from rural Guatemala designed to evaluate the effects of post-natal Zika virus on ND (DMID 16-0057), we evaluated the association between cumulative illness and ND delay and stunting.MethodsInfants enrolled at 0-3 months of age underwent weekly at-home surveillance for caregiver-reported syndromic illness, including cough, fever and vomiting/diarrhea for a 12-month period. Anthropometric assessments and ND testing by Guatemalan psychologists using the Mullen Scales of Early Learning (MSEL) were perforrmed at 12-15 months of age. Multivariable generalized linear regression models were used to test associations between syndromic illness in infancy, 12-15-month MSEL Early Learning Composite (ELC) Score, and stunting (height-for-age < -2 SD) at 12-15 months.ResultsThe cohort (n=425) had a mean enrollment age of 1.3 months; 202 (48%) were female, 387 (91%) self-reported a literate mother, and 301 (71%) were breastfeeding at study completion. Infants had reported illness for a median of 16 weeks during the surveillance period; cough was reported most frequently (median=11 weeks, range=0-37 weeks). Lower maternal education (p=0.007) and literacy (p=0.002) as well as infant age (p=0.007) and male gender (p=0.004) were associated with MSEL ELC Score <85 (-1 SD). After adjusting for gender, breastfeeding, age, and maternal literacy, the cumulative number of weeks with reported cough (p=0.0009), fever (p=0.0001), or any syndromic illness (p=0.0007) were associated with decreased 12-month MSEL ECL Score; there was no association with diarrhea/vomiting (p=0.36). There was no association between caregiver-reported syndromic illnesses (any type) and stunting at final study visit.ConclusionIn a cohort of Guatemalan infants, cumulative fever and cough episodes were significantly associated with lower MSEL ELC Score, whereas there was no association with diarrhea/vomiting. In this low-resource community, these findings highlight the potential negative ND consequences of febrile illness and persistent cough in the first year of life. NIAID Contract HHSN272201300015I Task Order HHSN27200013 (Co-PIs: FMM and EJA).Disclosures Molly Lamb, PhD, BioFire (Grant/Research Support) Evan J. Anderson, MD, Sanofi Pasteur (Scientific Research Study Investigator)

Teratogen update: Zika virus and pregnancy.

Zika virus was first identified in Uganda in 1947 but received little attention until 2015 when a large outbreak of Zika virus illness followed by an increased number of babies born with microcephaly occurred in Brazil. Zika virus spread rapidly throughout the Americas, and in 2016 was identified as a cause of microcephaly and other serious birth defects. Since that time, much has been learned about the Zika virus. The virus is primarily spread by the bite of Aedes species mosquitoes; however, other forms of transmission (e.g., sexual and intrauterine) have been recognized. Although postnatal Zika virus infection typically causes mild or no symptoms, effects on infants born to prenatally infected mothers can be severe and include structural birth defects and neurodevelopmental effects. The risk of a structural birth defect among infants born to mothers with confirmed or suspected Zika virus infection during pregnancy has ranged from 5 to 10%. The timing of Zika infection during pregnancy affects risk, with higher risks with the first-trimester infection. Neurodevelopmental effects are seen even in infants who appear normal in the newborn period. Although cases of Zika virus infection have fallen in the Americas, the Zika virus remains an active threat in some regions of the world. The development of a Zika vaccine will require continued focus and investment. Until a Zika vaccine is available, prevention efforts for pregnant women include avoidance of travel to areas with active Zika transmission, avoidance of mosquito bites for those living in or traveling to areas with Zika transmission, and protection against sexual transmission.

Neurodevelopmental findings in children 20-30months of age with postnatal Zika infection at 1-12months of age, Colombia, September-November 2017.

Zika virus (ZIKV) infection during pregnancy can cause infant brain and eye abnormalities and has been associated with adverse neurodevelopmental outcomes in exposed infants. Evidence is limited on ZIKV's effects on children infected postnatally within the first year of life. To determine whether any adverse neurodevelopmental outcomes occurred in early childhood for children infected postnatally with ZIKV during infancy, given the neurotoxicity of ZIKV infection and the rapid brain development that occurs in infancy and early childhood. The Colombia Instituto Nacional de Salud (INS) conducted health and developmental screenings between September and November 2017 to evaluate 60 children at ages 20-30months who had laboratory-confirmed symptomatic postnatal ZIKV infection at ages 1-12months. We examined the frequency of adverse neurologic, hearing, eye, and developmental outcomes as well as the relationship between age at Zika symptom onset and developmental outcomes. Nine of the 60 (15.0%) children had adverse outcomes on the neurologic, hearing, or eye examination. Six of the 47 (12.8%) children without these adverse findings, and who received a valid developmental screening, had an alert score in the hearing-language domain which signals the need for additional developmental evaluation. Neurologic, hearing, eye, and developmental findings suggest reassuring results. Since the full spectrum of neurodevelopmental outcomes in children postnatally infected with ZIKV remains unknown, routine paediatric care is advised to monitor the development of these children to ensure early identification of any adverse neurodevelopmental outcomes.

Long-term alterations in brain and behavior after postnatal Zika virus infection in infant macaques

Zika virus (ZIKV) infection has a profound impact on the fetal nervous system. The postnatal period is also a time of rapid brain growth, and it is important to understand the potential neurobehavioral consequences of ZIKV infection during infancy. Here we show that postnatal ZIKV infection in a rhesus macaque model resulted in long-term behavioral, motor, and cognitive changes, including increased emotional reactivity, decreased social contact, loss of balance, and deficits in visual recognition memory at one year of age. Structural and functional MRI showed that ZIKV-infected infant rhesus macaques had persistent enlargement of lateral ventricles, smaller volumes and altered functional connectivity between brain areas important for socioemotional behavior, cognitive, and motor function (e.g. amygdala, hippocampus, cerebellum). Neuropathological changes corresponded with neuroimaging results and were consistent with the behavioral and memory deficits. Overall, this study demonstrates that postnatal ZIKV infection in this model may have long-lasting neurodevelopmental consequences.

Long-term alterations in brain and behavior after postnatal Zika virus infection in infant macaques

Long-term alterations in brain and behavior after postnatal Zika virus infection in infant macaques

Performance of Zika Assays in the Context of Toxoplasma gondii, Parvovirus B19, Rubella Virus, and Cytomegalovirus (TORCH) Diagnostic Assays.

Infections during pregnancy that may cause congenital abnormalities have been recognized for decades, but their diagnosis is challenging. This was again illustrated with the emergence of Zika virus (ZIKV), highlighting the inherent difficulties in estimating the extent of pre- and postnatal ZIKV complications because of the difficulties in establishing definitive diagnoses. We reviewed the epidemiology, infection kinetics, and diagnostic methods used for Toxoplasma gondii, parvovirus B19, rubella virus, and cytomegalovirus (TORCH) infections and compared the results with current knowledge of ZIKV diagnostic assays to provide a basis for the inclusion of ZIKV in the TORCH complex evaluations. Similarities between TORCH pathogens and ZIKV support inclusion of ZIKV as an emerging TORCH infection. Our review evaluates the diagnostic performance of various TORCH diagnostic assays for maternal screening, fetal screening, and neonatal screening. We show that the sensitivity, specificity, and positive and negative predictive value of TORCH complex pathogens are widely variable, stressing the importance of confirmatory testing and the need for novel techniques for earlier and accurate diagnosis of maternal and congenital infections. In this context it is also important to acknowledge different needs and access to care for different geographic and resource settings.

Adenovirus Vector-Based Vaccines Confer Maternal-Fetal Protection against Zika Virus Challenge in Pregnant IFN-αβR−/− Mice

Maternal infection with Zika virus (ZIKV) can lead to microcephaly and other congenital abnormalities of the fetus. Although ZIKV vaccines that prevent or reduce viremia in non-pregnant mice have been described, a maternal vaccine that provides complete fetal protection would be desirable. Here, we show that adenovirus (Ad) vector-based ZIKV vaccines induce potent neutralizing antibodies that confer robust maternal and fetal protection against ZIKV challenge in pregnant, highly susceptible IFN-αβR-/- mice. Moreover, passive transfer of maternal antibodies from vaccinated dams protected pups against post-natal ZIKV challenge. These data suggest that Ad-based ZIKV vaccines may be able to provide protection in pregnant females against fetal ZIKV transmission in utero as well as in infants against ZIKV infection after birth.

2801. Post-Natal Zika Virus Infection and Impact on Neurodevelopment Among a Cohort of Children in Rural Guatemala

BackgroundThe impact of early post-natal Zika virus (ZIKV) infection on neurodevelopment (ND) is unknown. A prospective study of post-natal ZIKV infection in rural Guatemala (ZIKV study) enrolled a cohort of children ages 1–5 years, including children previously enrolled in a dengue virus (DENV) study during the 2015–2016 ZIKV epidemic. We evaluated ND outcomes by age and ZIKV infection status.MethodsSubjects enrolled in the ZIKV study June 2017–April 2018 underwent ND testing using the Mullen Scales of Early Learning (MSEL) at baseline and 12 months later. ZIKV/DENV-1/2 FRNT50 was performed on enrollment and on banked serum samples from the 2015 to 2016 subset. ZIKV serostatus and MSEL scores were correlated using multiple linear mixed models, adjusted for age and gender when appropriate, to evaluate their association. Geolocation was used to explore clustering of ZIKV serostatus and MSEL score.ResultsWe enrolled 183 children (43% female, mean age 3.2 years). Of these, 38 (21%) were classified as ZIKV-positive (+), 111 (61%) ZIKV-negative (-), 31 (17%) ZIKV-possible, and 3 (2%) ZIKV-indeterminate. ZIKV(+) cases and higher composite MSEL scores clustered in more densely populated areas (Figure 1). ZIKV(+) serostatus was associated with higher MSEL composite (increase in log score 0.09, P = 0.003) and subdomain scores: fine motor (0.13, P = 0.011), visual reception (0.15, P = 0.002), receptive language (0.09, P = 0.041), gross motor (0.14, P = 0.09), and expressive language (0.09, P = 0.058) (Figure 2). Of the 78 children (43%) with 2015–2016 samples, 46 (59%) remained ZIKV(−), 16 (21%) seroconverted from ZIKV(−) or possible/indeterminate to ZIKV(+), and 16 (21%) were indeterminate when enrolled in the ZIKV study. ZIKV seroconversion was associated with higher composite (0.13, P = 0.02) MSEL scores compared with ZIKV(−).ConclusionIn this exploratory analysis, post-natal ZIKV infection was not associated with adverse ND outcomes in children age 1–5 years. Overall, ZIKV(+) status was associated with higher average ND scores than ZIKV(−), and scores decreased with age for most children, independent of ZIKV status. The correlation of ZIKV(+) status and higher MSEL scores may be confounded by geographic-related factors or other confounders. NIAID Contract HHSN272201300015I Task Order HHSN27200013 (Co-PIs: FMM & EJA). DisclosuresFlor M. Munoz, M.D, Biocryst: Grant/Research Support; CDC: Research Grant; Moderna: Other Financial or Material Support, Safety Monitoring Board Member/Chair; NIH: Research Grant; Novavax: Research Grant; UP to Date: Author and Editor - Royalties, Other Financial or Material Support.

Fatal Zika virus infection in the Americas: A systematic review

IntroductionWhile death due to Zika virus (ZIKV) infection has been described, reports of fatal cases have been infrequent and no systematic reviews on the subject have been published. MethodsA systematic review of the literature in four databases was performed to assess fatal outcomes of postnatal ZIKV infection and the available evidence that links ZIKV infection to death. ResultsThree hundred and eleven articles were retrieved; 20 of them were epidemiological reports from surveillance agencies and ministries of health. After screening by abstract and title, 59 articles were selected for full-text assessment. Of these, 35 were excluded (with reasons) and 24 were finally included for qualitative analysis. A total of 51 reported deaths associated with ZIKV infection in nine countries were identified. The majority of cases (56.9%) were not related to Guillain–Barré syndrome. Cases from three countries accounted for 67.6% of the deaths. ZIKV infection was laboratory-confirmed in the majority of cases (64.7%). DiscussionZIKV was not considered to be a dangerous, and much less a lethal pathogen, until very recently. However, an increasing number of fatalities have been published in the literature since the first death was reported in 2016. Additional research is needed to elucidate factors that may mediate the pathogenesis of severe, atypical, and fatal disease.

Postnatal Zika virus infection of nonhuman primate infants born to mothers infected with homologous Brazilian Zika virus

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.

Zika Virus Infection in Hypothalamus Causes Hormone Deficiencies and Leads to Irreversible Growth Delay and Memory Impairment in Mice

Zika virus (ZIKV) can cause microcephaly in the fetus. However, its effects on body growth and the development of children with postnatal ZIKV infection are largely unknown. To examine this, we intraperitoneally challenged mouse pups with ZIKV. Infection causes an irreversible growth delay and deficits in spatial learning and memory, with growth-relevant hormones significantly reduced during infection. These effects are associated with ZIKV RNA expression in the hypothalamus, blood, and brain but not inthe pituitary and thyroid. Infection is also associated with hypothalamic inflammation, and ZIKV antigen isdetectable in neuroendocrine cells producingthyrotropin-releasing hormone. Moreover, early administration of growth hormone could significantly improve growth delay. Our results demonstrate that ZIKV can infect the hypothalamus, causing multi-hormone deficiencies and delayed growth and development in a mouse model. Therefore, prospective multidisciplinary follow-up of ZIKV-infected children may be necessary to understand potential effects of this virus on childhood development.

Maternal immunization with a DNA vaccine candidate elicits specific passive protection against post-natal Zika virus infection in immunocompetent BALB/c mice

Zika virus (ZIKV) infection is closely associated in the fetus with microcephaly and in the adults with Guillain-Barré syndrome and even male infertility. It is an urgent international priority to develop a safe and effective vaccine that offers protection to both women of childbearing age and their children. In this study, female immunocompetent BALB/c mice were immunized with a DNA-based vaccine candidate, pVAX1-ZME, expressing the prM/E protein of ZIKV, and the immunogenicity for maternal mice and the post-natal protection for suckling mice were evaluated. It was found that administration with three doses of 50 μg pVAX1-ZME via in vivo electroporation induced robust ZIKV-specific cellular and long-term humoral immune responses with high and sustained neutralizing activity in adult mice. Moreover, using a maternal immunization protocol, neutralizing antibodies provided specific passive protection against ZIKV infection in neonatal mice and effectively inhibited the growth delay. This vaccine candidate is expected to be further evaluated in higher animals, and maternal vaccination shows great promise for protecting both women of childbearing age and their offspring against post-natal ZIKV infection. The vaccinated mothers and ZIKV-challenged pups provide key insight into Zika vaccine evaluation in an available fully immunocompetent animal model.

Postnatal Zika virus infection is associated with persistent abnormalities in brain structure, function, and behavior in infant macaques.

The Zika virus (ZIKV) epidemic is associated with fetal brain lesions and other serious birth defects classified as congenital ZIKV syndrome. Postnatal ZIKV infection in infants and children has been reported; however, data on brain anatomy, function, and behavioral outcomes following infection are absent. We show that postnatal ZIKV infection of infant rhesus macaques (RMs) results in persistent structural and functional alterations of the central nervous system compared to age-matched controls. We demonstrate ZIKV lymphoid tropism and neurotropism in infant RMs and histopathologic abnormalities in the peripheral and central nervous systems including inflammatory infiltrates, astrogliosis, and Wallerian degeneration. Structural and resting-state functional magnetic resonance imaging (MRI/rs-fMRI) show persistent enlargement of lateral ventricles, maturational changes in specific brain regions, and altered functional connectivity (FC) between brain areas involved in emotional behavior and arousal functions, including weakened amygdala-hippocampal connectivity in two of two ZIKV-infected infant RMs several months after clearance of ZIKV RNA from peripheral blood. ZIKV infection also results in distinct alterations in the species-typical emotional reactivity to acute stress, which were predicted by the weak amygdala-hippocampal FC. We demonstrate that postnatal ZIKV infection of infants in this model affects neurodevelopment, suggesting that long-term clinical monitoring of pediatric cases is warranted.

Postnatal Zika virus infection is associated with persistent abnormalities in brain structure, function, and behavior in infant macaques

Postnatal Zika virus infection is associated with persistent abnormalities in brain structure, function, and behavior in infant macaques