Emergence of Congenital Zika Syndrome: Viewpoint From the Front Lines

Congenital and Perinatal Viral Infections: Consequences for the Mother and Fetus

Viruses are the most common congenital infections in humans and an important cause of foetal malformations, neonatal morbidity, and mortality. The effects of these infections, which are transmitted in utero (transplacentally), during childbirth or in the puerperium depend on the timing of the infections. These vary from miscarriages (usually with infections in very early pregnancy), congenital malformations (when the infections occur during organogenesis) and morbidity (with infections occurring late in pregnancy, during childbirth or after delivery). The most common of these viruses are cytomegalovirus, hepatitis, herpes simplex type-2, parvovirus B19, rubella, varicella zoster and zika viruses. There are currently very few efficacious antiviral agents licensed for use in pregnancy. For most of these infections, therefore, prevention is mainly by vaccination (where there is a vaccine). The administration of immunoglobulins to those exposed to the virus to offer passive immunity or appropriate measures to avoid being infected would be options to minimise the infections and their consequences. In this review, we discuss some of the congenital and perinatal infections and their consequences on both the mother and fetus and their management focusing mainly on prevention.

Oligodontia in the Clinical Spectrum of Syndromes: A Systematic Review

The aim of this systematic review was to describe the clinical and genetic features of syndromes showing oligodontia as a sign. The review was performed according to the PRISMA 2020 checklist guidelines, and the search was conducted using PubMed, Scopus, Lilacs, Web of science, Livivo, and EMBASE and supplemented by a gray literature search on Google Scholar and ProQuest, applying key terms relevant to the research questions. The systematic review identified 47 types of syndromes in 83 studies, and the most common was hypohidrotic ectodermal dysplasia, which was reported in 24 patients in 22 studies. Other common syndromes that reported oligodontia included Axenfeld-Rieger syndrome, Witkop's syndrome, Ellis-van Creveld syndrome, blepharocheilodontic syndrome, and oculofaciocardiodental syndrome. The X-linked mode of inheritance was the most reported (n = 13 studies), followed by the autosomal dominant (n = 13 studies). The review describes the main syndromes that may have oligodontia as a clinical sign and reinforces the need for orodental-facial examining for adequate diagnosis and treatment of the affected patients. Molecular analysis in order to better understand the occurrence of oligodontia is imperative.

The burden of global outbreaks: Photos of the daily lives of children with congenital Zika syndrome during the COVID-19 pandemic

INTRODUCTION

In Brazil, more than 3500 children with congenital Zika syndrome (CZS) face difficulties participating in activities of daily living, which may be aggravated by health emergencies, such as the COVID-19 pandemic. Participation could be defined as the individual's involvement in daily life situations, and participation restrictions are problems that may arise in involvement in everyday situations.

AIM

To explore the daily lives of children with CZS during the COVID-19 pandemic using photographic narratives captured by mothers and discuss possible strategies to improve participation results.

METHODS

In this participatory action research, seven young Brazilian mothers acted as co-researchers using photovoice to describe the experiences of their children with CZS (from 2 to 5 years old). Also, mothers contributed to validate the contents. The research was conducted online and included the following steps: pilot study, recruitment, individualized training, sociodemographic interview, photovoice training, photo taking, focus group for contextualization, data transcription and analysis and validation of analyses by the mothers.

RESULTS

Content analysis revealed five categories that influenced the participation of the children: participation preferences, family relationships, access to healthcare, access to education and social isolation. Regarding participation preferences, mothers reported their children's desire to play with peers and family members and have autonomy. Mothers described the family environment as a happy, peaceful and safe place for the children. Lack of therapy was perceived to negatively impact the health of children; thus, treatments were considered essential for child development. Access to education included accessibility of remote education and a perceived lack of infrastructure and pedagogical preparation. Last, social isolation due to COVID-19 directly affected the daily lives and behaviour of the children, interrupting therapies and medical appointments.

CONCLUSION

The photos and narratives captured several aspects of the daily lives of children with CZS impacted by the COVID-19 pandemic, reinforcing the importance of considering the negative effects of social isolation and offering education and social assistance to promote participation and integral health.

PATIENT/PUBLIC CONTRIBUTION

Consistent with a participatory action research framework, Mothers acted as co-researchers and participated in all stages of the research, especially in validating the data analysed by the researchers.

EDIII-Fc induces protective immune responses against the Zika virus in mice and rhesus macaque

Zika virus can infect the fetus through the placental barrier, causing ZIKV congenital syndrome and even miscarriage, which can cause great harm to pregnant women and infants. Currently, there is no vaccine and drug available to combat the Zika virus. In this study, we designed a fusion protein named EDIII-Fc, including the EDIII region of Zika E protein and human IgG Fc fragment, and obtained 293T cells that stably secreted EDIII-Fc protein using the lentiviral expression system. Mice were immunized with the EDIII-Fc protein, and it was observed that viral replication was significantly inhibited in the immunized mice compared to non-immunized mice. In rhesus macaques, we found that EDIII-Fc effectively induce the secretion of neutralizing antibodies and T cell immunity. These experimental data provide valid data for further use of Zika virus E protein to prepare an effective, safe, affordable Zika vaccine.

Language skills development in children with congenital Zika virus syndrome

BACKGROUND

The characterization of the phenotype of children with congenital Zika virus syndrome (CZS) is an ongoing process, since many characteristics can only be described with the advancing age of children providing some insights into the long-term sequelae.

AIMS

To describe emerging findings on the impact of CZS on language development in children with CZS in a 4-year longitudinal study.

METHODS AND PROCEDURES

39 boys and 44 girls with CZS were allocated into four groups according to age ranging from 12 to 36 months. Language development was assessed using the Early Language Milestone Scale.

OUTCOMES AND RESULTS

Visual, expressive, and receptive auditory skills of patients were lower than expected for their age. Despite producing vowel sounds, they did not babble; despite present hearing, the majority of the children did not understand simple commands. In over 4 years of follow-up, there was no evolution in language parameters, with the children stagnating at the language skills corresponding to 3 months of age.

CONCLUSIONS AND IMPLICATIONS

Most children with CZS are not able to produce vocalic sounds, but some may be able to communicate basic needs through alternative communication. WHAT THIS PAPER ADDS?: Some babies with CZS died prenatally, at birth, or in the first year of life due to associated complications such as respiratory infection, dysphagia, and epilepsy. However, the functionality of the future remains uncertain for surviving babies. This study adds information about the impact of Zika Virus on the central nervous system and, consequently, the severity and complexity of the CZS language. Over 4 years of follow-up, no evolution in language parameters was observed in children with CSZ. Children with CZS demonstrate severe neurodevelopmental impairment, stagnating in language skills at the age of 3 months. In the future, some of them may be able to communicate their basic needs through alternative communication.

Nuclear accumulation of host transcripts during Zika Virus Infection

Zika virus (ZIKV) infects fetal neural progenitor cells (NPCs) causing severe neurodevelopmental disorders in utero. Multiple pathways involved in normal brain development are dysfunctional in infected NPCs but how ZIKV centrally reprograms these pathways remains unknown. Here we show that ZIKV infection disrupts subcellular partitioning of host transcripts critical for neurodevelopment in NPCs and functionally link this process to the up-frameshift protein 1 (UPF1). UPF1 is an RNA-binding protein known to regulate decay of cellular and viral RNAs and is less expressed in ZIKV-infected cells. Using infrared crosslinking immunoprecipitation and RNA sequencing (irCLIP-Seq), we show that a subset of mRNAs loses UPF1 binding in ZIKV-infected NPCs, consistent with UPF1's diminished expression. UPF1 target transcripts, however, are not altered in abundance but in subcellular localization, with mRNAs accumulating in the nucleus of infected or UPF1 knockdown cells. This leads to diminished protein expression of FREM2, a protein required for maintenance of NPC identity. Our results newly link UPF1 to the regulation of mRNA transport in NPCs, a process perturbed during ZIKV infection.

The Innate Defense in the Zika-Infected Placenta

Zika virus (ZIKV) is an arthropod-borne virus that belongs to the Flaviviridae family, genus Flavivirus and was first isolated 1947 in Uganda, Africa, from the serum of a sentinel Rhesus monkey. Since its discovery, the virus was responsible for major outbreaks in several different countries, being linked to severe complications in pregnant women, neonatal birth defects and the congenital zika syndrome. Maternal-fetal transmission of ZIKV can occur in all trimesters of pregnancy, and the role of the placenta and its cells in these cases is yet to be fully understood. The decidua basalis and chorionic villi, maternal-fetal components of the placenta, contain a rich immunological infiltrate composed by Hofbauer cells, mastocytes, dendritic cells and macrophages, primary cells of the innate immune response that have a role that still needs to be better investigated in ZIKV infection. Recent studies have already described several histopathological features and the susceptibility and permissiveness of placenta cells to infection by the Zika virus. In this review, we address some of the current knowledge on the innate immune responses against ZIKV, especially in the placenta.

The economic burden of congenital Zika Syndrome in Brazil: an overview at 5 years and 10 years

Background

The aim of this paper is to estimate the economic burden of children with congenital Zika Syndrome (CZS) in Brazil over 5–10 years.

Methods

We conducted a modelling study based on data collected in a case–control study in Brazil, including children with CZS (cases) and typically developing children (controls), born in 2015 and 2016. In total, 484 participants were recruited in two sites, Recife and Rio de Janeiro. Social and economic information was collected in a survey from the carers of cases and controls, and detailed healthcare utilisation was recorded for each child in the Rio de Janeiro cohort prospectively in a database. We used this information to estimate the cost per child with severe, moderate and no CZS and incremental cost per child with severe and moderate versus no CZS from a disaggregated societal perspective. These estimates were incorporated into an economic burden model to estimate the incremental burden of the CZS epidemic in Brazil over 5 years and 10 years.

Findings

The societal cost per child with severe CZS was US$50 523 to 10 years of age (born in 2015 and 2016), substantially higher than the costs for moderate CZS (US$29 283) and without CZS (US$12 331). The incremental economic burden of severe versus no CZS in Brazil over 10 years was US$69.4 million from the household and US$129.0 million from the government perspective. For moderate CZS, these figures amounted to US$204.1 million and US$86.6 million. Over 10 years, 97% of the total societal economic cost of severe CZS is borne by the government, but only 46% for moderate CZS.

Interpretation

The economic burden of CZS is high at the household, provider and government levels. The compensatory government payments helped to alleviate some of the additional costs incurred by families with a child qualifying for the disability benefits, and could be scaled to include the children with moderate CZS.

A platform of assays for the discovery of anti-Zika small-molecules with activity in a 3D-bioprinted outer-blood-retina model

The global health emergency posed by the outbreak of Zika virus (ZIKV), an arthropod-borne flavivirus causing severe neonatal neurological conditions, has subsided, but there continues to be transmission of ZIKV in endemic regions. As such, there is still a medical need for discovering and developing therapeutical interventions against ZIKV. To identify small-molecule compounds that inhibit ZIKV disease and transmission, we screened multiple small-molecule collections, mostly derived from natural products, for their ability to inhibit wild-type ZIKV. As a primary high-throughput screen, we used a viral cytopathic effect (CPE) inhibition assay conducted in Vero cells that was optimized and miniaturized to a 1536-well format. Suitably active compounds identified from the primary screen were tested in a panel of orthogonal assays using recombinant Zika viruses, including a ZIKV Renilla luciferase reporter assay and a ZIKV mCherry reporter system. Compounds that were active in the wild-type ZIKV inhibition and ZIKV reporter assays were further evaluated for their inhibitory effects against other flaviviruses. Lastly, we demonstrated that wild-type ZIKV is able to infect a 3D-bioprinted outer-blood-retina barrier tissue model and disrupt its barrier function, as measured by electrical resistance. One of the identified compounds (3-Acetyl-13-deoxyphomenone, NCGC00380955) was able to prevent the pathological effects of the viral infection on this clinically relevant ZIKV infection model.

Health surveillance and development of children with congenital Zika Virus syndrome: an integrative literature review

Objective:

To identify scientific knowledge about the attention to health surveillance and development of Brazilian children under the age of three years involving the Congenital Zika virus (ZIKV) Syndrome.

Data sources:

This is an integrative literature review of primary studies with Brazilian children under three years of age from 2015 to 2019. The searches were carried out in the databases Latin American and Caribbean Literature in Health Sciences (LILACS), US National Library of Medicine (PubMed), Cumulative Index to Nursing and Allied Health Literature (CINAHL), SCOPUS and Web of Science. It was carried out by crossing the keywords in English (child, child development and Zika virus) and in Portuguese (criança, desenvolvimento infantil e Zika vírus), with the combination of the Boolean operator “AND”.

Data synthesis:

The knowledge produced is related to the specific health and development problems of children affected by the Congenital ZIKV Syndrome, with clinical characteristics, care demands, multiprofessional performance, health monitoring and surveillance needs.

Conclusions:

This integrative review synthesized scientific knowledge by adding aspects that reinforce the relevance of appropriate approaches to assess and care for children, linked to the engagement of caregivers, the need to document, evaluate and track the situations of children in early childhood and long-term, management coordination of care and its challenges in the context of primary health care.

A Novel Radiologic Finding to Predict Ophthalmic Abnormalities in Children With Congenital Zika Syndrome

BACKGROUND

The Zika virus (ZIKV) epidemic had devastating consequences in Brazil. We investigated whether a radiologic finding (ie, infratentorial abnormalities) was associated with sight-threatening defects in children born with congenital Zika syndrome (CZS). We also investigated whether ophthalmic abnormalities correlated with head circumference (HC) and gestational age of infection.

METHODS

Cross-sectional evaluation based upon a previous cohort from March 2016 to December 2018, in Paraíba, Brazil. The study population was comprised of children born to mothers with laboratory-confirmed ZIKV infection during pregnancy (ZIKV reverse transcriptase polymerase chain reaction [RT-PCR]+) and children born with clinical and radiologic features of CZS.

RESULTS

A total of 75 infants had complete data. All 75 had brain calcifications. Microcephaly was present in 53 (71%) of them. Infratentorial abnormalities were present in 17 infants (22.7%). Ophthalmic abnormalities were seen in 16 of the 17 children (94%) with infratentorial abnormalities, while 28% of children without infratentorial abnormalities had ophthalmic findings (odds ratio [OR]: 42.0; 95% confidence interval [CI]: 5.1-342.9). Similar associations were observed when macular chorioretinal atrophy and optic nerve abnormalities were analyzed individually (OR: 23.7; 95% CI: 6.0-93.3 and OR: 11.5; 95% CI: 3.3-40.0, respectively). Infratentorial abnormalities were more frequently associated with ophthalmic abnormalities (94%) than microcephaly (43.4%) (P < .001). Mean HC was statistically different between groups with and without ophthalmic abnormalities (P = .01). A statistically significant difference in gestational age between both groups was not noted (P = .12).

CONCLUSIONS

In children with CZS, the presence of infratentorial abnormalities is a significant predictor of ophthalmic abnormalities. All neonates whose mothers had ZIKV exposure during pregnancy should have an ophthalmologic examination.

Clinical and Biochemical Features of Hypopituitarism Among Brazilian Children With Zika Virus-Induced Microcephaly

IMPORTANCE

The Zika virus infects progenitor neuron cells, disrupts cerebral development, and, in mice, drives hypothalamic defects. Patients with microcephaly caused by congenital Zika infection present with midline cerebral defects, which may result in hypopituitarism.

OBJECTIVE

To analyze postnatal growth and the presence of clinical and biochemical features associated with hypopituitarism in children with congenital Zika infections.

DESIGN, SETTING, AND PARTICIPANTS

In this prospective cohort study at 2 public referral hospitals in Bahia, Brazil, specializing in the treatment of congenital Zika infection, clinical data and growth parameters of 65 patients with the infection were evaluated. Data were analyzed from April 2017 through July 2018.

EXPOSURE

Congenital Zika infection.

MAIN OUTCOMES AND MEASURES

Length, weight, and head circumference were measured at birth and during follow up (ie, at 27 months of life) for each patient. Basal levels of free thyroxine, thyrotropin, cortisol, corticotropin, prolactin, insulin-like growth factor 1, insulin-like growth factor binding protein 3, urine and plasma osmolality, electrolytes, glucose, and insulin were evaluated at the age of 26 months to 28 months. All patients underwent central nervous system computed tomography scans and ophthalmic and otoacoustic evaluations at the time of this investigation or had done so previously.

RESULTS

Among 65 patients (38 [58.4%] male; median [interquartile range] age at enrollment, 27 [26-28] months), 61 patients presented with severe brain defects (93.8%), including corpus callosum agenesis or hypoplasia (ie, midline brain defects; 25 patients [38.5%]) and optic nerve atrophy (38 patients [58.5%]). Most patients presented with severe neurodevelopmental delay (62 of 64 patients [96.9%]). Past or present clinical signs of hypopituitarism were rare, occurring in 3 patients (4.6%). Severe microcephaly, compared with mild or moderate microcephaly, was associated with a shorter length by median (interquartile range) z score at birth (-1.9 [-2.5 to -1.0] vs -0.3 [-1.0 to 0]; P < .001), but this difference did not persist at 27 months (-1.6 [-2.3 to -0.3] vs -2.9 [-4.0 to -1.2]; P = .06). Growth hormone deficiency or hypothyroidism were not observed in any patients, and glucose and insulin levels were within reference ranges for all patients. Low cortisol levels (ie, below 3.9 µg/dL) were observed in 4 patients (6.2%). These 4 patients presented with low (ie, below 7.2 pg/mL) or inappropriately low (ie, below 30 pg/mL) corticotropin levels. Low corticotropin levels (ie, below 7.2 pg/mL) were observed in 6 patients (9.2%). Diabetes insipidus was evaluated in 21 patients; it was confirmed in 1 patient (4.8%) and suggested in 3 patients (14.3%).

CONCLUSIONS AND RELEVANCE

This study found that congenital Zika infection with microcephaly was associated with midline brain defects and optic nerve atrophy. Children with congenital Zika infections presented with prenatal growth impairments with a lack of postnatal catch-up, as shown by persistent short length from birth until 27 months; these impairments were not associated with growth hormone deficiency. Patients also presented with severe developmental delay that was not associated with hypothyroidism, while central adrenal insufficiency and diabetes insipidus occurred in some patients.

A Double-Blind, Randomized, Placebo-Controlled Phase 1 Study of Ad26.ZIKV.001, an Ad26-Vectored Anti-Zika Virus Vaccine

BACKGROUND

Zika virus (ZIKV) may cause severe congenital disease after maternal-fetal transmission. No vaccine is currently available.

OBJECTIVE

To assess the safety and immunogenicity of Ad26.ZIKV.001, a prophylactic ZIKV vaccine candidate.

DESIGN

Phase 1 randomized, double-blind, placebo-controlled clinical study. (ClinicalTrials.gov: NCT03356561).

SETTING

United States.

PARTICIPANTS

100 healthy adult volunteers.

INTERVENTION

Ad26.ZIKV.001, an adenovirus serotype 26 vector encoding ZIKV M-Env, administered in 1- or 2-dose regimens of 5 × 10¹⁰ or 1 × 10¹¹ viral particles (vp), or placebo.

MEASUREMENTS

Local and systemic adverse events; neutralization titers by microneutralization assay (MN50) and T-cell responses by interferon-γ enzyme-linked immunospot and intracellular cytokine staining; and protectivity of vaccine-induced antibodies in a subset of participants through transfer in an exploratory mouse ZIKV challenge model.

RESULTS

All regimens were well tolerated, with no safety concerns identified. In both 2-dose regimens, ZIKV neutralizing titers peaked 14 days after the second vaccination, with geometric mean MN50 titers (GMTs) of 1065.6 (95% CI, 494.9 to 2294.5) for 5 × 10¹⁰ vp and 956.6 (595.8 to 1535.8) for 1 × 10¹¹ vp. Titers persisted for at least 1 year at a GMT of 68.7 (CI, 26.4-178.9) for 5 × 10¹⁰ vp and 87.0 (CI, 29.3 to 258.6) for 1 × 10¹¹ vp. A 1-dose regimen of 1 × 10¹¹ vp Ad26.ZIKV.001 induced seroconversion in all participants 56 days after the first vaccination (GMT, 103.4 [CI, 52.7 to 202.9]), with titers persisting for at least 1 year (GMT, 90.2 [CI, 38.4 to 212.2]). Env-specific cellular responses were induced. Protection against ZIKV challenge was observed after antibody transfer from participants into mice, and MN50 titers correlated with protection in this model.

LIMITATION

The study was conducted in a nonendemic area, so it did not assess safety and immunogenicity in a flavivirus-exposed population.

CONCLUSION

The safety and immunogenicity profile makes Ad26.ZIKV.001 a promising candidate for further development if the need reemerges.

PRIMARY FUNDING SOURCE

Janssen Vaccines and Infectious Diseases.

Differential Longevity of Memory CD4 and CD8 T Cells in a Cohort of the Mothers With a History of ZIKV Infection and Their Children

Background: Zika virus (ZIKV) infection causes for mild and self-limiting disease in healthy adults. In newborns, it can occasionally lead to a spectrum of malformations, the congenital Zika syndrome (CZS). Thus, little is known if mothers and babies with a history of ZIKV infection were able to develop long-lasting T-cell immunity. To these issues, we measure the prevalence of ZIKV T-cell immunity in a cohort of mothers infected to the ZIKV during pregnancy in the 2016–2017 Zika outbreak, who gave birth to infants affected by neurological complications or asymptomatic ones.

Results: Twenty-one mothers and 18 children were tested for IFN-γ ELISpot and T-cell responses for flow cytometry assays in response to CD4 ZIKV and CD8 ZIKV megapools (CD4 ZIKV MP and CD8 ZIKV MP). IFN-γ ELISpot responses to ZIKV MPs showed an increased CD4 and CD8 T-cell responses in mothers compared to children. The degranulation activity and IFN-γ-producing CD4 T cells were detected in most mothers, and children, while in CD8 T-cells, low responses were detected in these study groups. The total Temra T cell subset is enriched for IFN-γ+ CD4 T cells after stimulation of CD4 ZIKV MP.

Conclusion: Donors with a history of ZIKV infection demonstrated long-term CD4 T cell immunity to ZIKV CD4 MP. However, the same was not observed in CD8 T cells with the ZIKV CD8 MP. One possibility is that the cytotoxic and pro-inflammatory activities of CD8 T cells are markedly demonstrated in the early stages of infection, but less detected in the disease resolution phase, when the virus has already been eliminated. The responses of mothers' T cells to ZIKV MPs do not appear to be related to their children's clinical outcome. There was also no marked difference in the T cell responses to ZIKV MP between children affected or not with CZS. These data still need to be investigated, including the evaluation of the response of CD8 T cells to other ZIKV peptides.

Zika Virus Infection Leads to Demyelination and Axonal Injury in Mature CNS Cultures

Understanding how Zika virus (Flaviviridae; ZIKV) affects neural cells is paramount in comprehending pathologies associated with infection. Whilst the effects of ZIKV in neural development are well documented, impact on the adult nervous system remains obscure. Here, we investigated the effects of ZIKV infection in established mature myelinated central nervous system (CNS) cultures. Infection incurred damage to myelinated fibers, with ZIKV-positive cells appearing when myelin damage was first detected as well as axonal pathology, suggesting the latter was a consequence of oligodendroglia infection. Transcriptome analysis revealed host factors that were upregulated during ZIKV infection. One such factor, CCL5, was validated in vitro as inhibiting myelination. Transferred UV-inactivated media from infected cultures did not damage myelin and axons, suggesting that viral replication is necessary to induce the observed effects. These data show that ZIKV infection affects CNS cells even after myelination-which is critical for saltatory conduction and neuronal function-has taken place. Understanding the targets of this virus across developmental stages including the mature CNS, and the subsequent effects of infection of cell types, is necessary to understand effective time frames for therapeutic intervention.

Risk of sexually transmitted Zika virus in a cohort of economically disadvantaged urban residents

In order to understand the disease burden of sexually transmitted Zika virus (ZIKV), we prospectively followed a cohort of 359 adult and adolescent residents of an urban community in Salvador, Brazil through the 2015 ZIKV epidemic. Later, in 2017, we used a retrospective survey to associate sexual behavior during the epidemic with ZIKV infection as defined by IgG3-NS1 ELISA. We found that males who engaged in casual sexual encounters during the epidemic were more likely (ORa=6.2; 95%CI 1.2-64.1) to be ZIKV positive, suggesting that specific groups may be at increased risk of sexually transmitted infections.

Contemporary Understanding of Ebola and Zika Virus in Pregnancy

Understanding the pathophysiology, management, and prevention of emerging infectious diseases among pregnant women is imperative to achieve a successful response from the medical community. Ebola and Zika viruses represent infections with profound public health implications. In particular, Ebola virus is associated with high case fatality and pregnancy and neonatal loss rates, while Zika virus has been associated with multiple congenital anomalies; these features present critical clinical dilemmas for management of pregnant and reproductive aged women. The objective of this article is to summarize key background information and best practices for management of Ebola and Zika virus in pregnancy.

Evolving viral and serological stages of Zika virus RNA-positive blood donors and estimation of incidence of infection during the 2016 Puerto Rican Zika epidemic: an observational cohort study

BACKGROUND

Puerto Rico began screening blood donations for Zika virus RNA with nucleic acid amplification tests (NAATs) on April 3, 2016, because of an emerging Zika virus outbreak. We followed up positive donors to assess the dynamics of viral and serological markers during the early stages of Zika virus infection and update the estimate of infection incidence in the Puerto Rican population during the outbreak.

METHODS

Blood donations from volunteer donors in Puerto Rico were screened for the presence of Zika virus RNA using the cobas Zika NAAT. Positive donations were further tested to confirm infection, estimate viral load, and identify Zika virus-specific IgM antibodies. Individuals with positive blood donations were invited to attend follow-up visits. Donations with confirmed infection (defined as detection of Zika virus RNA or IgM on additional testing of index or follow-up samples) were assessed for stage of infection according to Zika virus RNA detectability in simulated minipools, viral load, and Zika virus IgM status. A three-step process was used to estimate the mean duration of NAAT reactivity of Zika virus in human plasma from individuals identified pre-seroconversion with at least one follow up visit and to update the 2016 incidence estimate of Zika virus infection.

FINDINGS

Between April 3 and Dec 31, 2016, 53 112 blood donations were screened for Zika virus, of which 351 tested positive, 339 had confirmed infections, and 319 could be staged. Compared with IgM-positive index donations (n=110), IgM-negative index donations (n=209) had higher mean viral loads (1·1 × 10⁶vs 8·3 × 10⁴ international units per mL) and were more likely to be detected in simulated minipools (93% [n=194] vs 26% [n=29]). The proportions of donations with confirmed infections that had viral RNA detected only in individual-donation NAATs (ie, not in simulated minipools) and were IgM positive increased as the epidemic evolved. The estimated mean duration of NAAT detectability in the 140 donors included in the follow-up study was 11·70 days (95% CI 10·06-14·36). Applying this detection period to the observed proportion of donations that were confirmed NAAT positive yielded a Zika virus seasonal incidence estimate of 21·1% (95% CI 18·1-24·1); 768 101 infections in a population of 3 638 773 in 2016.

INTERPRETATION

Characterisation of early Zika virus infection has implications for blood safety because infectivity of blood donations and utility of screening methods likely correlate with viral load and serological stage of infection. Our findings also have implications for diagnostic testing, public health surveillance, and epidemiology, and we estimate that around 21% of the Puerto Rican population was infected during the 2016 outbreak.

FUNDING

Biomedical Advanced Research and Development Authority, National Heart, Lung, and Blood Institute.

Clinical characteristics of children with congenital Zika syndrome: a case series

BACKGROUND

The congenital Zika syndrome involves structural brain changes, including ventriculomegaly, thin cerebral cortices, abnormal gyral pattern, cortical malformations, hypoplasia of the corpus callosum, myelination delay, subcortical diffuse calcifications, brainstem hypoplasia, and microcephaly in newborns.

OBJECTIVE

This study aimed to describe the clinical characteristics of children with congenital Zika syndrome; to compare the outcomes of infants infected in the first (1T, n=20) and second trimesters of pregnancy (2T, n=11); to investigate correlations between birth weight, birth and follow-up head circumference, birth gestational age, and gross motor scores.

METHODS

Participants were evaluated with Alberta Infant Motor Scale (AIMS) and part A of the Gross Motor Function Measure (GMFM-A). ANOVA compared head circumference, birth gestational age, birth weight, and gross motor performance of 1T and 2T.

RESULTS

The correlations were investigated by Pearson correlation coefficients. ANOVA showed differences in birth and follow-up head circumferences. Head circumference was smaller in 1T, compared to 2T. Motor performance was classified as below the fifth percentile in AIMS in all children and 1T showed lower scores in prone, sitting, and total AIMS score, compared to 2T. Children ranged from 8 to 78% on GMFM-A and there was a poorer motor performance of 1T. Nineteen children showed hypertonia, six showed normal tone and six showed hypotonia. Birth head circumference was correlated with AIMS prone postural control. Follow-up head circumference was correlated to prone, supine and total AIMS scores. Smaller head circumference at birth and follow-up denoted poorer postural control.

DISCUSSION

Children with congenital Zika syndrome showed microcephaly at birth and follow-up. Smaller head circumferences and poorer motor outcomes were observed in 1T. Infants showed poor visual and motor outcomes. Moderate positive correlations between birth and follow-up head circumference and gross motor function were found.

Oral and maxillofacial conditions, dietary aspects, and nutritional status of children with congenital Zika syndrome

OBJECTIVE

The aim of this study was to investigate oral and maxillofacial outcomes in children with congenital Zika syndrome (CZS) and the presence of nonnutritive sucking habits, functional habits, and features related to breastfeeding and nutrition of these children.

STUDY DESIGN

We conducted a cross-sectional study with 45 children with CZS and 50 healthy controls in Sergipe state, Brazil, from February 2018 to June 2018. Demographic and clinical data, including breastfeeding and feeding data, were obtained for each child. Additionally, oral and maxillofacial evaluation was performed.

RESULTS

Low weight (prevalence rate [PR] 8.33; 95% confidence interval [CI] 2.02-34.45), nonexclusive breastfeeding up to 6 months (PR 1.56; 95% CI 1.18-2.08); mouth breathing (PR 3.46; 95% CI 1.83-6.52); difficulty in swallowing (PR 6.00; 95% CI 2.53-14.25); and excessive salivation (PR 4.81; 95% CI 2.18-10.62) were more frequent in children with CZS. Children with CZS were more likely to have abnormal insertion of the upper labial frenulum (PR 7.04; 95% CI 2.23-22.20); ogival palate (PR 3.70; 95% CI 1.63-8.40), dental enamel defects (PR 2.22; 95% CI 1.05-4.69); and delayed dental eruption (PR 8.89; 95% CI 1.16-68.32) compared with healthy children.

CONCLUSIONS

Children with CZS had a higher frequency of problems related to breastfeeding, low weight, and oral and maxillofacial abnormalities compared with healthy children.

Effective control of early Zika virus replication by Dengue immunity is associated to the length of time between the 2 infections but not mediated by antibodies

Little is known about the contribution of virus-specific and cross-reacting antibodies (Abs) or the cellular immune response generated by a primary dengue (DENV) infection on the course of a secondary zika (ZIKV) infection in vivo. Here we show that the length of time between DENV/ZIKV infections has a qualitative impact on controlling early ZIKV replication. Depletion of DENV2-specific Abs in sera confirmed that those type-specific Abs do not contribute to ZIKV control. We show that the magnitude and durability of the neutralizing antibodies (nAbs) induced by a secondary ZIKV infection is modest compared to the response induced after a secondary heterologous DENV infection. Our in vivo results are showing a complex interplay between the cellular and innate immune responses characterized by a high frequency of plasmacytoid dendritic cells (pDC) correlating with an increase in the frequency of DENV antigen specific T cells and a significant control of ZIKV replication which is time dependent. Taken together, our results suggest that early after ZIKV infection other mechanisms such as the innate and cellular immune responses may play a predominant role in controlling ZIKV replication. Regardless of the time elapsed between infections there was no evidence of in vivo antibody-dependent enhancement (ADE) of ZIKV by DENV immunity. These findings have pivotal implications while interpreting ZIKV pathogenesis in flavivirus-experimented populations, diagnostic results interpretation and vaccine designs and schedules among others.

From our previous work in non-human primates and others using humans, we believe that previous DENV immunity confers some degree of protection against ZIKV infection. However, at least two highly relevant questions remain unanswered. One is precisely if the time between primary DENV and a subsequent ZIKV infections may play a role in the degree of protection conferred by DENV immunity. The second question is related to the mechanisms of cross-protection. In this work we provide evidences that a period of 12 months between DENV and ZIKV infections has a significant impact controlling ZIKV replication compared to a shorter period of 3 months. We also provide evidences that the pre-existing DENV Abs play no role controlling early ZIKV replication. Our results strongly suggest that the mechanisms controlling ZIKV replication are related to the complex interaction between the innate and the cellular immune responses. Our results have significant implications for vaccine design and schedules.

Influence of herd immunity in the cyclical nature of arboviruses

We review and contrast the evidence for an effect of amplifying host herd immunity on circulation and human exposure to arboviruses. Herd immunity of short-lived West Nile virus avian amplifying hosts appears to play a limited role in levels of enzootic circulation and spillover infections of humans, which are not amplifiers. In contrast, herd immunity of nonhuman primate hosts for enzootic Zika, dengue, and chikungunya viruses is much stronger and appears to regulate to a large extent the periodicity of sylvatic amplification in Africa. Following the recent Zika and chikungunya pandemics, human herd immunity in the Americas quickly rose to ∼50% in many regions, although seroprevalence remains patchy. Modeling from decades of chikungunya circulation in Asia suggests that this level of herd immunity will suppress for many years major chikungunya and Zika epidemics in the Americas, followed by smaller outbreaks as herd immunity cycles with a periodicity of up to several decades.

Zika virus and microcephaly in Southeast Asia: A cause for concern?

Zika virus (ZIKV), a mosquito transmitted virus in the family Flaviviridae, genus Flavivirus, recently emerged to cause infections in more than 70 countries and territories around the world. While human infection is normally asymptomatic, it can also result in a mild febrile disease similar to dengue fever. However, when a pregnant woman is infected, ZIKV can cause fetal abnormalities including microcephaly. Evidence has suggested that ZIKV has circulated in Southeast Asia for more than a decade and yet cases of ZIKV associated microcephaly remain sparsely documented. This review seeks to collate the information currently existing on ZIKV associated microcephaly in Southeast Asia, and assess the potential future risk posed by this virus.

Engagement of Fathers in Parent Group Interventions for Children with Congenital Zika Syndrome: A Qualitative Study

We aimed to explore the engagement of fathers in a community-based group intervention (Juntos) for children with congenital Zika syndrome (CZS) and their caregivers in Brazil. Six Juntos groups were facilitated from August 2017 to May 2018. We conducted a qualitative study to evaluate the feasibility and acceptability of the intervention for fathers of children with CZS. Methods included participant observation, focus group discussions, and semi-structured interviews of fathers with a child enrolled in the program. Data collected were transcribed, coded and thematically analyzed to explore father preference for, and beliefs about the intervention and to assess potential barriers and enablers to their involvement. Forty-nine families (61 participants) enrolled, of whom 20% (12/61) were fathers. Seven (58%) fathers attended more than 7 out of 10 sessions. The content of Juntos was found to be acceptable to those fathers who attended. Participation in the group offered fathers the opportunity to share experiences of caring for their child and demonstrate their importance as care agents. Work commitments, and the view of mothers as primary caregivers were barriers to engagement of fathers. Facilitators to engagement included a presentation of clear objectives for fathers’ involvement and the opportunity to learn a practical skill related to caring for their child. A better understanding of the perspectives of fathers is crucial to help increase their involvement in parenting interventions.

Social and economic impacts of congenital Zika syndrome in Brazil: Study protocol and rationale for a mixed-methods study

Global concern broke out in late 2015 as thousands of children in Brazil were born with microcephaly, which was quickly linked to congenital infection with Zika virus (ZIKV). ZIKV is now known to cause a wider spectrum of severe adverse outcomes-congenital Zika syndrome (CZS)-and also milder impairments. This study aimed to explore the social and economic impacts of CZS in Brazil. Data was collected through mixed methods across two settings: Recife City and Jaboatão dos Guararapes in Pernambuco State (the epicentre of the epidemic), and the city of Rio de Janeiro (where reports of ZIKV infection and CZS were less frequent). Data was collected May 2017-January 2018. Ethical standards were adhered to throughout the research. In-depth qualitative interviews were conducted with: mothers and other carers of children with CZS (approximately 30 per setting), pregnant women (10-12 per setting), men and women of child-bearing age (16-20 per setting), and health professionals (10-12 per setting). Thematic analysis was undertaken independently by researchers from at least two research settings, and these were shared for feedback. A case-control study was undertaken to quantitatively explore social and economic differences between caregivers of a child with CZS (cases) and caregivers with an unaffected child (controls). We aimed to recruit 100 cases and 100 controls per setting, from existing studies. The primary caregiver, usually the mother, was interviewed using a structured questionnaire to collect information on: depression, anxiety, stress, social support, family quality of life, health care and social service use, and costs incurred by families. Multivariable logistic regression analyses were used to compare outcomes for cases and controls. Costs incurred as a result of CZS were estimated from the perspective of the health system, families and society. Modelling was undertaken to estimate the total economic burden of CZS from those three perspectives.

Social and economic impacts of congenital Zika syndrome in Brazil: Study protocol and rationale for a mixed-methods study

Global concern broke out in late 2015 as thousands of children in Brazil were born with microcephaly, which was quickly linked to congenital infection with Zika virus (ZIKV). ZIKV is now known to cause a wider spectrum of severe adverse outcomes-congenital Zika syndrome (CZS)-and also milder impairments. This study aimed to explore the social and economic impacts of CZS in Brazil. Data was collected through mixed methods across two settings: Recife City and Jaboatão dos Guararapes in Pernambuco State (the epicentre of the epidemic), and the city of Rio de Janeiro (where reports of ZIKV infection and CZS were less frequent). Data was collected May 2017-January 2018. Ethical standards were adhered to throughout the research. In-depth qualitative interviews were conducted with: mothers and other carers of children with CZS (approximately 30 per setting), pregnant women (10-12 per setting), men and women of child-bearing age (16-20 per setting), and health professionals (10-12 per setting). Thematic analysis was undertaken independently by researchers from at least two research settings, and these were shared for feedback. A case-control study was undertaken to quantitatively explore social and economic differences between caregivers of a child with CZS (cases) and caregivers with an unaffected child (controls). We aimed to recruit 100 cases and 100 controls per setting, from existing studies. The primary caregiver, usually the mother, was interviewed using a structured questionnaire to collect information on: depression, anxiety, stress, social support, family quality of life, health care and social service use, and costs incurred by families. Multivariable logistic regression analyses were used to compare outcomes for cases and controls. Costs incurred as a result of CZS were estimated from the perspective of the health system, families and society. Modelling was undertaken to estimate the total economic burden of CZS from those three perspectives.

International prospective observational cohort study of Zika in infants and pregnancy (ZIP study): study protocol

BACKGROUND

Until recently, Zika virus (ZIKV) infections were considered mild and self-limiting. Since 2015, they have been associated with an increase in microcephaly and other birth defects in newborns. While this association has been observed in case reports and epidemiological studies, the nature and extent of the relationship between ZIKV and adverse pregnancy and pediatric health outcomes is not well understood. With the unique opportunity to prospectively explore the full spectrum of issues related to ZIKV exposure during pregnancy, we undertook a multi-country, prospective cohort study to evaluate the association between ZIKV and pregnancy, neonatal, and infant outcomes.

METHODS

At research sites in ZIKV endemic regions of Brazil (4 sites), Colombia, Guatemala, Nicaragua, Puerto Rico (2 sites), and Peru, up to 10,000 pregnant women will be recruited and consented in the first and early second trimesters of pregnancy and then followed through delivery up to 6 weeks post-partum; their infants will be followed until at least 1 year of age. Pregnant women with symptomatic ZIKV infection confirmed by presence of ZIKV RNA and/or IgM for ZIKV will also be enrolled, regardless of gestational age. Participants will be tested monthly for ZIKV infection; additional demographic, physical, laboratory and environmental data will be collected to assess the potential interaction of these variables with ZIKV infection. Delivery outcomes and detailed infant assessments, including physical and neurological outcomes, will be obtained.

DISCUSSION

With the emergence of ZIKV in the Americas and its association with adverse pregnancy outcomes in this region, a much better understanding of the spectrum of clinical outcomes associated with exposure to ZIKV during pregnancy is needed. This cohort study will provide information about maternal, fetal, and infant outcomes related to ZIKV infection, including congenital ZIKV syndrome, and manifestations that are not detectable at birth but may appear during the first year of life. In addition, the flexibility of the study design has provided an opportunity to modify study parameters in real time to provide rigorous research data to answer the most critical questions about the impact of congenital ZIKV exposure.

TRIAL REGISTRATION

NCT02856984 . Registered August 5, 2016. Retrospectively registered.

Misperceived Risks of Zika-related Microcephaly in India

After the discovery that Zika virus (ZIKV) could cause microcephaly and other birth defects, we have scrambled to understand how. Now, spreading along with the virus is misinformation that a ZIKV mutation is responsible for microcephaly. Putting too much onus on a single mutation could enhance a crisis in India.

Small-Animal Models of Zika Virus

Zika virus (ZIKV) infection can result in serious consequences, including severe congenital manifestations, persistent infection in the testes, and neurologic sequelae. After a pandemic emergence, the virus has spread to much of North and South America and has been introduced to many countries outside of ZIKV-endemic areas as infected travelers return to their home countries. Rodent models have been important in gaining a better understanding of the wide range of disease etiologies associated with ZIKV infection and for the initial phase of developing countermeasures to prevent or treat viral infections. We discuss herein the advantages and disadvantages of small-animal models that have been developed to replicate various aspects of disease associated with ZIKV infection.

Impact of preexisting dengue immunity on Zika virus emergence in a dengue endemic region

The clinical outcomes associated with Zika virus (ZIKV) in the Americas have been well documented, but other aspects of the pandemic, such as attack rates and risk factors, are poorly understood. We prospectively followed a cohort of 1453 urban residents in Salvador, Brazil, and, using an assay that measured immunoglobulin G3 (IgG3) responses against ZIKV NS1 antigen, we estimated that 73% of individuals were infected during the 2015 outbreak. Attack rates were spatially heterogeneous, varying by a factor of 3 within a community spanning 0.17 square kilometers. Preexisting high antibody titers to dengue virus were associated with reduced risk of ZIKV infection and symptoms. The landscape of ZIKV immunity that now exists may affect the risk for future transmission.

Emerging arboviruses and implications for pediatric transplantation: A review

Recent years have brought a rise in newly emergent viral infections, primarily in the form of previously known arthropod-transmitted viruses that have increased significantly in both incidence and geographical range. Of particular note are DENV, CHIKV, and ZIKV, which are transmitted mostly by Aedes species of mosquitoes that exhibit a wide and increasing global distribution. Being important pathogens for the general population, these viruses have the potential to be devastating in the international transplant community, with graft rejection and death as possible outcomes of infection. In this review, we discuss the current state of knowledge for these viruses as well as repercussions of infection in the solid organ and HSCT population, with a focus, when possible, on pediatric patients.

Modeling Zika Virus-Associated Birth Defects in Nonhuman Primates

In utero infection with Zika virus (ZIKV) during pregnancy can lead to the development of birth defects and postnatal deficits. A nonhuman primate (NHP) model of congenital ZIKV infection can help fill the gaps in knowledge where tissue studies are required to define viral pathogenesis and identify targets for therapeutic intervention. This model system has already identified critical features of ZIKV pathogenesis in congenital infection. Before translating these NHP studies to human clinical trials, we must understand the similarities and differences between human and NHP fetal immune system development, neural development, and infant assessment tools. Because of the overall similarity between fetal and infant development in humans and NHPs, this NHP model can complement human clinical trials by defining immune correlates of protection and evaluating therapeutic interventions.

Cytokine-Mediated Tissue Injury in Non-human Primate Models of Viral Infections

Viral infections trigger robust secretion of interferons and other antiviral cytokines by infected and bystander cells, which in turn can tune the immune response and may lead to viral clearance or immune suppression. However, aberrant or unrestricted cytokine responses can damage host tissues, leading to organ dysfunction, and even death. To understand the cytokine milieu and immune responses in infected host tissues, non-human primate (NHP) models have emerged as important tools. NHP have been used for decades to study human infections and have played significant roles in the development of vaccines, drug therapies and other immune treatment modalities, aided by an ability to control disease parameters, and unrestricted tissue access. In addition to the genetic and physiological similarities with humans, NHP have conserved immunologic properties with over 90% amino acid similarity for most cytokines. For example, human-like symptomology and acute respiratory syndrome is found in cynomolgus macaques infected with highly pathogenic avian influenza virus, antibody enhanced dengue disease is common in neotropical primates, and in NHP models of viral hepatitis cytokine-induced inflammation induces severe liver damage, fibrosis, and hepatocellular carcinoma recapitulates human disease. To regulate inflammation, anti-cytokine therapy studies in NHP are underway and will provide important insights for future human interventions. This review will provide a comprehensive outline of the cytokine-mediated exacerbation of disease and tissue damage in NHP models of viral infections and therapeutic strategies that can aid in prevention/treatment of the disease syndromes.

Prolonged Detection of Zika Virus Nucleic Acid Among Symptomatic Pregnant Women: A Cohort Study

A prospective cohort of women with reverse transcription polymerase chain reaction (RT-PCR) confirmed Zika virus infection aged 18-39 years in Puerto Rico found that pregnant women have about a 3-fold longer estimated median detection of Zika virus RNA in serum, which can increase definitive diagnosis of infection and facilitate timely and appropriate clinical management.

Skills attained by infants with congenital Zika syndrome: Pilot data from Brazil

The recent Zika outbreak and its link to microcephaly and other birth defects in infants exposed in utero have garnered widespread international attention. Based on the severity of birth defects the extent of impairment in these infants is expected to be profound; however, virtually nothing is known regarding the developmental and behavioral sequela of congenital Zika syndrome. This pilot study collected parent-reported patterns of development and sleep in 47 infants with confirmed congenital Zika syndrome who are being followed for clinical services at the Altino Ventura Foundation (FAV) in Recife, Brazil. With assistance from clinicians at FAV, caregivers completed Brazilian Portuguese versions of the Ages and Stages Questionnaire, 3^rd edition (ASQ-3) and the Brief Infant Sleep Questionnaire (BISQ). All infants were between 13–22 months of age at the time of the assessment. At 16 months of age, none of the children displayed age appropriate developmental skills. Most (~ 75%) mastered some communication and gross motor skills at around a 6–8-month level. Communication and gross motor skills were relative strengths for the sample, while problem-solving and fine motor skills were relative weaknesses. Sleep was noted to be a problem for around 18% of the sample. In utero exposure to the Zika virus will have lifelong consequences for affected children and their families. Understanding the developmental and behavioral trajectories of affected infants will help identify appropriate family supports to improve quality of life.

Congenital Viral Infection: Traversing the Uterine-Placental Interface

Why certain viruses cross the physical barrier of the human placenta but others do not is incompletely understood. Over the past 20 years, we have gained deeper knowledge of intrauterine infection and routes of viral transmission. This review focuses on human viruses that replicate in the placenta, infect the fetus, and cause birth defects, including rubella virus, varicella-zoster virus, parvovirus B19, human cytomegalovirus (CMV), Zika virus (ZIKV), and hepatitis E virus type 1. Detailed discussions include ( a) the architecture of the uterine-placental interface, ( b) studies of placental explants ex vivo that provide insights into the infection and spread of CMV and ZIKV to the fetal compartment and how these viruses undermine early development, and ( c) novel treatments and vaccines that limit viral replication and have the potential to reduce dissemination, vertical transmission and the occurrence of congenital disease.

Evolution of Two Major Zika Virus Lineages: Implications for Pathology, Immune Response, and Vaccine Development

Zika virus (ZIKV) became a public health emergency of global concern in 2015 due to its rapid expansion from French Polynesia to Brazil, spreading quickly throughout the Americas. Its unexpected correlation to neurological impairments and defects, now known as congenital Zika syndrome, brought on an urgency to characterize the pathology and develop safe, effective vaccines. ZIKV genetic analyses have identified two major lineages, Asian and African, which have undergone substantial changes during the past 50 years. Although ZIKV infections have been circulating throughout Africa and Asia for the later part of the 20th century, the symptoms were mild and not associated with serious pathology until now. ZIKV evolution also took the form of novel modes of transmission, including maternal-fetal transmission, sexual transmission, and transmission through the eye. The African and Asian lineages have demonstrated differential pathogenesis and molecular responses in vitro and in vivo. The limited number of human infections prior to the 21st century restricted ZIKV research to in vitro studies, but current animal studies utilize mice deficient in type I interferon (IFN) signaling in order to invoke enhanced viral pathogenesis. This review examines ZIKV strain differences from an evolutionary perspective, discussing how these differentially impact pathogenesis via host immune responses that modulate IFN signaling, and how these differential effects dictate the future of ZIKV vaccine candidates.

Consequences of in utero exposure to Zika virus in offspring of AG129 mice

Zika virus (ZIKV) can cause various diseases in offspring after congenital infection. The purpose of this study was to identify disease phenotypes in pups exposed to ZIKV in utero. Female interferon-α/β, -γ receptor knockout mice (AG129) were infected intraperitoneally with ZIKV 7.5 days' post coitus (dpc). Viral RNA, antigen and infectious virus were detected in some, but not all, maternal and fetal tissues at various times during gestation. Fetuses of infected dams had significant intrauterine growth restriction (IUGR), which was more pronounced as females neared parturition. Pups born to infected dams were significantly smaller and had significantly shortened skull lengths, as determined by measurement with a caliper and by micro-CT analysis, as compared with age-matched controls. Growth rates of exposed pups after birth, however, was similar to sham-exposed offspring. Viral RNA was detected in pups of infected dams after birth. A lower survival rate was observed in neonates exposed to ZIKV in utero. A mortality rate of over 50%, attributed to consequences of ZIKV infection, occurred after birth in pups born to infected dams. A transient hearing loss was observed in some animals exposed to virus in utero. No motor deficits or cognitive deficits were detected using running wheel or viral paresis scoring assays. Abnormalities in offspring included smaller size, shorter skull length and increased neonatal mortality, while the only functional deficit we could detect was a low incidence of transient hearing loss.

Zika Virus as an Emerging Neuropathogen: Mechanisms of Neurovirulence and Neuro-Immune Interactions

Zika virus (ZIKV) is an emerging arbovirus of the genus Flaviviridae, which causes a febrile illness and has spread from across the Pacific to the Americas in a short timeframe. Convincing evidence has implicated the ZIKV to incident cases of neonatal microcephaly and a set of neurodevelopmental abnormalities referred to as the congenital Zika virus syndrome. In addition, emerging data points to an association with the ZIKV and the development of the so-called Guillain-Barre syndrome, an acute autoimmune polyneuropathy. Accumulating knowledge suggests that neurovirulent strains of the ZIKV have evolved from less pathogenic lineages of the virus. Nevertheless, mechanisms of neurovirulence and host-pathogen neuro-immune interactions remain incompletely elucidated. This review provides a critical discussion of genetic and structural alterations in the ZIKV which could have contributed to the emergence of neurovirulent strains. In addition, a mechanistic framework of neuro-immune mechanisms related to the emergence of neuropathology after ZIKV infection is discussed. Recent advances in knowledge point to avenues for the development of a putative vaccine as well as novel therapeutic strategies. Nevertheless, there are unique unmet challenges that need to be addressed in this regard. Finally, a research agenda is proposed.

Seizures as a Complication of Congenital Zika Syndrome in Early Infancy

Zika virus transmission in Brazil was linked to a large outbreak of microcephaly but less is known about longer term anthropometric and neurological outcomes. We studied a cohort of infants born between October 31, 2015, and January 9, 2016, in a state maternity hospital, followed up for 101 ± 28 days by home visits. Microcephaly (< 2 standard deviations, Intergrowth standard) occurred in 62 of 412 (15%) births. Congenital Zika syndrome (CZS) was diagnosed in 29 patients. Among CZS patients, we observed a significant gain in anthropometric measures (P < 0.001) but no significant gain in percentile for these measures. The main neurological outcome was epilepsy, occurring in 48% of infants at a rate of 15.6 cases per 100 patient-months, frequently requiring multiple anti-seizure medications. The cumulative fatality rate was 7.4% (95% confidence interval: 2.1-23.4%). Health-care professionals should be alerted on the high risk of epilepsy and death associated with CZS in early infancy and the need to actively screen for seizures and initiate timely treatment.

Current priorities in the Zika response

Zika virus (ZIKV), a single-stranded RNA virus of the Flaviviridae family, is an arbovirus (viruses transmitted by arthropods) transmitted to humans and non-human primates through the bites of infected female Aedes sp. mosquitoes. Although first isolated in 1947, it only recently emerged as a global threat, present in several countries resulting in a pandemic scenario. ZIKV infections may have severe outcomes, such as neurological impairment, and with the intrinsic ability of inducing microcephaly in fetuses of infected pregnant women, the virus has become a major public health problem. This review discusses some advances in diagnosis; vaccine development and the problems associated with their administration; the importance of the cross-reactivity with other flaviviruses in protecting or worsening the disease; the implications of the recent outbreak caused by the virus in the world; and future prospects for the complete understanding of this disease.

The Likely Impact of Congenital Zika Syndrome on Families: Considerations for Family Supports and Services

Congenital Zika virus infection has obvious implications for infants, and considerable research has addressed the nature and consequences of congenital Zika syndrome (CZS). Children with classic CZS meet the criteria for "children with medical complexity," and ongoing research is required to understand the range of needs and optimal treatment options. Far less attention has been given to the consequences of CZS for families, which are both immediate and lifelong. Although families of children with CZS have much in common with families of other children with disabilities, at least 4 features of CZS have special family implications: (1) the severity of the impact on children with obvious abnormalities at birth, coupled with the anticipation of a lifetime of caregiving and economic burdens; (2) uncertainty about the unfolding consequences, both for obviously affected children and for exposed children with no symptoms at birth; (3) a lack of specialized professional knowledge about the course of the disease or treatment options; and (4) social isolation, a lack of social or community supports, and potential stigma. Supporting families will require a family-centered approach to services, extensive care coordination, access to evolving new information, ongoing surveillance, formal and informal supports, and individualized child and family services.

Development of Infants With Congenital Zika Syndrome: What Do We Know and What Can We Expect?

The association between Zika virus infection during pregnancy and severe birth defects in infants has led to worldwide attention focused on the mechanisms of the disease and the prevention of future exposure. Surveillance efforts around the world continue with the goal of identifying and monitoring all potentially exposed women and their newborns. For infants who were born with congenital Zika syndrome (CZS) and their families, an uncertain future awaits. As infants who were born with CZS during the most recent outbreak enter their second year of life, new developments in the outcomes of the condition continue to unfold, providing some insight into the likely long-term sequalae. In this article, I review the literature on emerging findings regarding the impact of CZS on the developing infant and provide some predictions regarding the long-term outcomes and lifetime needs of these children and their families.

Ocular and uteroplacental pathology in a macaque pregnancy with congenital Zika virus infection

Congenital Zika virus (ZIKV) infection impacts fetal development and pregnancy outcomes. We infected a pregnant rhesus macaque with a Puerto Rican ZIKV isolate in the first trimester. The pregnancy was complicated by preterm premature rupture of membranes (PPROM), intraamniotic bacterial infection and fetal demise 49 days post infection (gestational day 95). Significant pathology at the maternal-fetal interface included acute chorioamnionitis, placental infarcts, and leukocytoclastic vasculitis of the myometrial radial arteries. ZIKV RNA was disseminated throughout fetal tissues and maternal immune system tissues at necropsy, as assessed by quantitative RT-PCR for viral RNA. Replicating ZIKV was identified in fetal tissues, maternal uterus, and maternal spleen by fluorescent in situ hybridization for viral replication intermediates. Fetal ocular pathology included a choroidal coloboma, suspected anterior segment dysgenesis, and a dysplastic retina. This is the first report of ocular pathology and prolonged viral replication in both maternal and fetal tissues following congenital ZIKV infection in a rhesus macaque. PPROM followed by fetal demise and severe pathology of the visual system have not been described in macaque congenital ZIKV infection previously. While this case of ZIKV infection during pregnancy was complicated by bacterial infection with PPROM, the role of ZIKV on this outcome cannot be precisely defined, and further nonhuman primate studies will determine if increased risk for PPROM or other adverse pregnancy outcomes are associated with congenital ZIKV infection.

Zika Virus Fatally Infects Wild Type Neonatal Mice and Replicates in Central Nervous System

Zika virus (ZIKV) has been defined as a teratogenic pathogen behind the increased number of cases of microcephaly in French Polynesia, Brazil, Puerto Rico, and other South American countries. Experimental studies using animal models have achieved tremendous insight into understanding the viral pathogenesis, transmission, teratogenic mechanisms, and virus-host interactions. However, the animals used in published investigations are mostly interferon (IFN)-compromised, either genetically or via antibody treatment. Herein, we studied ZIKV infection in IFN-competent mice using African (MR766) and Asian strains (PRVABC59 and SZ-WIV01). After testing four different species of mice, we found that BALB/c neonatal mice were resistant to ZIKV infection, that Kunming, ICR and C57BL/6 neonatal mice were fatally susceptible to ZIKV infection, and that the fatality of C57BL/6 neonates from 1 to 3 days old were in a viral dose-dependent manner. The size and weight of the brain were significantly reduced, and the ZIKV-infected mice showed neuronal symptoms such as hind-limb paralysis, tremor, and poor balance during walking. Pathologic and immunofluorescent experiments revealed that ZIKV infected different areas of the central nervous system (CNS) including gray matter, hippocampus, cerebral cortex, and spinal cord, but not olfactory bulb. Interestingly, ZIKV replicated in multiple organs and resulted in pathogenesis in liver and testis, implying that ZIKV infection may engender a high health risk in neonates by postnatal infection. In summary, we investigated ZIKV pathogenesis using an animal model that is not IFN-compromised.