Histopathological lesions of congenital Zika syndrome in newborn squirrel monkeys.

The absence of an adequate animal model for studies has limited the understanding of congenital Zika syndrome (CZS) in humans during the outbreak in America. In this study, we used squirrel monkeys (Saimiri collinsi), a neotropical primate (which mimics the stages of human pregnancy), as a model of Zika virus (ZIKV) infection. Seven pregnant female squirrel monkeys were experimentally infected at three different gestational stages, and we were able reproduce a broad range of clinical manifestations of ZIKV lesions observed in newborn humans. Histopathological and immunohistochemical analyses of early-infected newborns (2/4) revealed damage to various areas of the brain and ZIKV antigens in the cytoplasm of neurons and glial cells, indicative of CZS. The changes caused by ZIKV infection were intrauterine developmental delay, ventriculomegaly, simplified brain gyri, vascular impairment and neuroprogenitor cell dysfunction. Our data show that the ZIKV infection outcome in squirrel monkeys is similar to that in humans, indicating that this model can be used to help answer questions about the effect of ZIKV infection on neuroembryonic development and the morphological changes induced by CZS.

Role of Prenatal Ultrasonography and Amniocentesis in the Diagnosis of Congenital Zika Syndrome: A Systematic Review.

OBJECTIVE: To examine the relationship between prenatal diagnostics (ultrasound examination and amniotic fluid Zika virus testing) and postnatal congenital Zika syndrome abnormalities. DATA SOURCES: Systematic searches were performed in 27 databases, including ClinicalTrials.gov, from inception to July 1, 2019, for articles with the keywords "Zika," "prenatal," "ultrasound," and "amniocentesis." METHODS OF STUDY SELECTION: A total of 3,049 unique records were identified. Two reviewers independently assessed titles, abstracts, and full texts for relevance; 84 articles met the inclusion criteria. These articles describe 402 mother-fetus or mother-neonate dyads; 385 were included in the review of prenatal ultrasound examination, and 56 in the review of amniocentesis (39 in both). TABULATION, INTEGRATION, AND RESULTS: Among 195 fetuses with congenital Zika syndrome findings on prenatal ultrasound examination, postnatal congenital Zika syndrome abnormalities were reported for 153 (78%; 95% CI 7-84%). High proportions of microcephaly (76%; 95% CI 69-82%) and brain abnormalities (78%; 95% CI 69-86%) were confirmed postnatally. Among 190 fetuses without congenital Zika syndrome findings on prenatal ultrasound examination, 17% (95% CI 12-24%) had congenital Zika syndrome abnormalities identified postnatally. Structural congenital Zika syndrome abnormalities were identified postnatally in approximately equal proportions among dyads with and without Zika virus RNA detected in an amniotic fluid specimen (68% and 67%; 95% CI 52-82% and 95% CI 38-88%). In six pregnancies, Zika virus RNA was detected in amniotic fluid but not in a subsequent amniocentesis specimen. CONCLUSION: Prenatal ultrasound examination frequently detects structural findings associated with Zika virus infection; however, not all abnormalities are detected, and some may represent transient findings. As with other congenital infections, prenatal detection may vary with timing of infection, timing of ultrasound examination, technical expertise, and severity of abnormalities. The detection of Zika virus RNA in amniotic fluid in the included studies did not predict the risk for congenital Zika syndrome abnormalities in these cases, and clearance of Zika virus RNA from amniotic fluid appears possible after maternal infection. Diagnostic testing for Zika virus infection remains a shared decision between patients and clinicians, and more data are needed to define clinical predictors that will inform these decisions. SYSTEMATIC REVIEW REGISTRATION: PROSPERO, CRD42018080959.

Sequential Neuroimaging of the Fetus and Newborn With In Utero Zika Virus Exposure.

Importance: The evolution of fetal brain injury by Zika virus (ZIKV) infection is not well described. Objectives: To perform longitudinal neuroimaging of fetuses and infants exposed to in utero maternal ZIKV infection using concomitant magnetic resonance imaging (MRI) and ultrasonography (US), as well as to determine the duration of viremia in pregnant women with ZIKV infection and whether the duration of viremia correlated with fetal and/or infant brain abnormalities. Design, Setting, and Participants: A cohort of 82 pregnant women with clinical criteria for probable ZIKV infection in Barranquilla, Colombia, and Washington, DC, were enrolled from June 15, 2016, through June 27, 2017, with Colombian women identified by community recruitment and physician referral and travel-related cases of American women recruited from a Congenital Zika Program. Interventions and Exposures: Women received 1 or more MRI and US examinations during the second and/or third trimesters. Postnatally, infants underwent brain MRI and cranial US. Blood samples were tested for ZIKV. Main Outcomes and Measures: The neuroimaging studies were evaluated for brain injury and cerebral biometry. Results: Of the 82 women, 80 were from Colombia and 2 were from the United States. In 3 of 82 cases (4%), fetal MRI demonstrated abnormalities consistent with congenital ZIKV infection. Two cases had heterotopias and malformations in cortical development and 1 case had a parietal encephalocele, Chiari II malformation, and microcephaly. In 1 case, US results remained normal despite fetal abnormalities detected on MRI. Prolonged maternal polymerase chain reaction positivity was present in 1 case. Of the remaining 79 cases with normal results of prenatal imaging, postnatal brain MRI was acquired in 53 infants and demonstrated mild abnormalities in 7 (13%). Fifty-seven infants underwent postnatal cranial US, which detected changes of lenticulostriate vasculopathy, choroid plexus cysts, germinolytic/subependymal cysts, and/or calcification in 21 infants (37%). Conclusions and Relevance: In a cohort of pregnant women with ZIKV infection, prenatal US examination appeared to detect all but 1 abnormal fetal case. Postnatal neuroimaging in infants who had normal prenatal imaging revealed new mild abnormalities. For most patients, prenatal and postnatal US may identify ZIKV-related brain injury.

Biomimetic Placenta-Fetus Model Demonstrating Maternal-Fetal Transmission and Fetal Neural Toxicity of Zika Virus.

Recent global epidemics of viral infection such as Zika virus (ZIKV) and associated birth defects from maternal-fetal viral transmission highlights the critical unmet need for experimental models that adequately recapitulates the biology of the human maternal-fetal interface and downstream fetal development. Herein, we report an in vitro biomimetic placenta-fetus model of the maternal-fetal interface and downstream fetal cells. Using a tissue engineering approach, we built a 3D model incorporating placental trophoblast and endothelial cells into an extracellular matrix environment and validated formation of the maternal-fetal interface. We utilized this model to study ZIKV exposure to the placenta and neural progenitor cells. Our results indicated ZIKV infects both trophoblast and endothelial cells, leading to a higher viral load exposed to fetal cells downstream of the barrier. Viral inhibition by chloroquine reduced the amount of virus both in the placenta and transmitted to fetal cells. A sustained downstream neural cell viability in contrast to significantly reduced viability in an acellular model indicates that the placenta sequesters ZIKV consistent with clinical observations. These findings suggest that the placenta can modulate ZIKV exposure-induced fetal damage. Moreover, such tissue models can enable rigorous assessment of potential therapeutics for maternal-fetal medicine.

Gestational Stage and IFN-λ Signaling Regulate ZIKV Infection In Utero.

Although Zika virus (ZIKV)-induced congenital disease occurs more frequently during early stages of pregnancy, its basis remains undefined. Using established type I interferon (IFN)-deficient mouse models of ZIKV transmission in utero, we found that the placenta and fetus were more susceptible to ZIKV infection at earlier gestational stages. Whereas ZIKV infection at embryonic day 6 (E6) resulted in placental insufficiency and fetal demise, infections at midstage (E9) resulted in reduced cranial dimensions, and infection later in pregnancy (E12) caused no apparent fetal disease. In addition, we found that fetuses lacking type III IFN-λ signaling had increased ZIKV replication in the placenta and fetus when infected at E12, and reciprocally, treatment of pregnant mice with IFN-λ2 reduced ZIKV infection. IFN-λ treatment analogously diminished ZIKV infection in human midgestation fetal- and maternal-derived tissue explants. Our data establish a model of gestational stage dependence of ZIKV pathogenesis and IFN-λ-mediated immunity at the maternal-fetal interface.

Ultrasonographic observations of the fetal brain in the first 100 pregnant women with Zika virus infection in Trinidad and Tobago.

OBJECTIVE: To evaluate the fetal brain in pregnant women infected with Zika virus in a limited-resource setting. METHODS: In an observational study in Trinidad and Tobago, 100 pregnant women infected with Zika virus who were referred for fetal medicine services provided by a single clinician were enrolled from March 31 to September 2, 2016. Two-dimensional ultrasonography was undertaken. RESULTS: The women were aged 17-41 years (mean 27.5 ± 5.7). Six cases of fetal brain abnormalities consistent with Zika infection were detected before 26 gestational weeks. The gestational period at infection and time of presentation ranged, respectively, from 7+3 to 16+0  weeks and from 23+2 to 25+5  weeks. In all cases, centiles of the biparietal diameter and head circumference decreased progressively over time to below the third centile. The skull contour appeared irregular, owing to collapse or overlap of the fetal skull bones. In four cases, brain anomalies were not obvious on the transabdominal scan but were diagnosed on the transvaginal scan. In a further two cases, brain abnormalities presented after 26 weeks of gestation. CONCLUSION: Overall, 8.0% of women infected with Zika virus had fetuses with brain abnormalities suggestive of Zika congenital syndrome. Six cases were detected before 26 weeks and two cases after 26 weeks.

What Is New in Obstetric Imaging?: Best Articles From the Past Year.

This month we focus on current research in obstetric imaging. Dr. Dashe discusses five recent publications, which are concluded with a "bottom line" that is a take-home message. A complete reference for each can be found in on this page along with direct links to abstracts.

Diagnostic Accuracy of Ultrasound Scanning for Prenatal Microcephaly in the context of Zika Virus Infection: A Systematic Review and Meta-analysis.

To assess the accuracy of ultrasound measurements of fetal biometric parameters for prenatal diagnosis of microcephaly in the context of Zika virus (ZIKV) infection, we searched bibliographic databases for studies published until March 3rd, 2016. We extracted the numbers of true positives, false positives, true negatives, and false negatives and performed a meta-analysis to estimate group sensitivity and specificity. Predictive values for ZIKV-infected pregnancies were extrapolated from those obtained for pregnancies unrelated to ZIKV. Of 111 eligible full texts, nine studies met our inclusion criteria. Pooled estimates from two studies showed that at 3, 4 and 5 standard deviations (SDs)

Zika virus infection of adult and fetal STAT2 knock-out hamsters.

Zika virus (ZIKV) infection was investigated in adult and fetal STAT2 knock-out (KO) hamsters. Subcutaneous injection of ZIKV of adults resulted in morbidity, mortality, and infection of the uterus, placenta, brain, spinal cord, and testicles, thus providing an opportunity to evaluate congenital ZIKV infection in a second rodent species besides mice. ZIKV-infected cells with morphologies of Sertoli cells and spermatogonia were observed in the testes, which may have implications for sexual transmission and male sterility. Neonates exposed as fetuses to ZIKV at 8 days post-coitus were not smaller than controls. Nevertheless, infectious virus and ZIKV RNA was detected in some, but not all, placentas and fetal brains of KO hamsters. STAT2 KO hamsters may be useful for addressing sexual transmission, pathogenesis, routes of fetal infection, and neurological disease outcomes, and may also be used in antiviral or vaccine studies to identify intervention strategies.

Hydrocephalus and arthrogryposis in an immunocompetent mouse model of ZIKA teratogeny: A developmental study.

The teratogenic mechanisms triggered by ZIKV are still obscure due to the lack of a suitable animal model. Here we present a mouse model of developmental disruption induced by ZIKV hematogenic infection. The model utilizes immunocompetent animals from wild-type FVB/NJ and C57BL/6J strains, providing a better analogy to the human condition than approaches involving immunodeficient, genetically modified animals, or direct ZIKV injection into the brain. When injected via the jugular vein into the blood of pregnant females harboring conceptuses from early gastrulation to organogenesis stages, akin to the human second and fifth week of pregnancy, ZIKV infects maternal tissues, placentas and embryos/fetuses. Early exposure to ZIKV at developmental day 5 (second week in humans) produced complex manifestations of anterior and posterior dysraphia and hydrocephalus, as well as severe malformations and delayed development in 10.5 days post-coitum (dpc) embryos. Exposure to the virus at 7.5-9.5 dpc induces intra-amniotic hemorrhage, widespread edema, and vascular rarefaction, often prominent in the cephalic region. At these stages, most affected embryos/fetuses displayed gross malformations and/or intrauterine growth restriction (IUGR), rather than isolated microcephaly. Disrupted conceptuses failed to achieve normal developmental landmarks and died in utero. Importantly, this is the only model so far to display dysraphia and hydrocephalus, the harbinger of microcephaly in humans, as well as arthrogryposis, a set of abnormal joint postures observed in the human setting. Late exposure to ZIKV at 12.5 dpc failed to produce noticeable malformations. We have thus characterized a developmental window of opportunity for ZIKV-induced teratogenesis encompassing early gastrulation, neurulation and early organogenesis stages. This should not, however, be interpreted as evidence for any safe developmental windows for ZIKV exposure. Late developmental abnormalities correlated with damage to the placenta, particularly to the labyrinthine layer, suggesting that circulatory changes are integral to the altered phenotypes.

Zika virus cell tropism in the developing human brain and inhibition by azithromycin.

The rapid spread of Zika virus (ZIKV) and its association with abnormal brain development constitute a global health emergency. Congenital ZIKV infection produces a range of mild to severe pathologies, including microcephaly. To understand the pathophysiology of ZIKV infection, we used models of the developing brain that faithfully recapitulate the tissue architecture in early to midgestation. We identify the brain cell populations that are most susceptible to ZIKV infection in primary human tissue, provide evidence for a mechanism of viral entry, and show that a commonly used antibiotic protects cultured brain cells by reducing viral proliferation. In the brain, ZIKV preferentially infected neural stem cells, astrocytes, oligodendrocyte precursor cells, and microglia, whereas neurons were less susceptible to infection. These findings suggest mechanisms for microcephaly and other pathologic features of infants with congenital ZIKV infection that are not explained by neural stem cell infection alone, such as calcifications in the cortical plate. Furthermore, we find that blocking the glia-enriched putative viral entry receptor AXL reduced ZIKV infection of astrocytes in vitro, and genetic knockdown of AXL in a glial cell line nearly abolished infection. Finally, we evaluate 2,177 compounds, focusing on drugs safe in pregnancy. We show that the macrolide antibiotic azithromycin reduced viral proliferation and virus-induced cytopathic effects in glial cell lines and human astrocytes. Our characterization of infection in the developing human brain clarifies the pathogenesis of congenital ZIKV infection and provides the basis for investigating possible therapeutic strategies to safely alleviate or prevent the most severe consequences of the epidemic.

Gravidez em tempos de Zika: uma decisão tomada com muito amor e informação

Vivemos um tempo único, cheio de perguntas, fontes e ansiedade para os casais que planejam uma gravidez. Acreditamos que o nosso papel é promover uma conversa saudável para todos. Só assim poderemos ajudar quem deseja engravidar a tomar uma decisão baseada fatos científicos e motivada por um amor que durará por toda a vida.

Zika virus infection disrupts neurovascular development and results in postnatal microcephaly with brain damage.

Zika virus (ZIKV) infection of pregnant women can result in fetal brain abnormalities. It has been established that ZIKV disrupts neural progenitor cells (NPCs) and leads to embryonic microcephaly. However, the fate of other cell types in the developing brain and their contributions to ZIKV-associated brain abnormalities remain largely unknown. Using intracerebral inoculation of embryonic mouse brains, we found that ZIKV infection leads to postnatal growth restriction including microcephaly. In addition to cell cycle arrest and apoptosis of NPCs, ZIKV infection causes massive neuronal death and axonal rarefaction, which phenocopy fetal brain abnormalities in humans. Importantly, ZIKV infection leads to abnormal vascular density and diameter in the developing brain, resulting in a leaky blood-brain barrier (BBB). Massive neuronal death and BBB leakage indicate brain damage, which is further supported by extensive microglial activation and astrogliosis in virally infected brains. Global gene analyses reveal dysregulation of genes associated with immune responses in virus-infected brains. Thus, our data suggest that ZIKV triggers a strong immune response and disrupts neurovascular development, resulting in postnatal microcephaly with extensive brain damage.

Infant feeding in areas of Zika virus transmission

July 4, 2016 - The World Health Organization (WHO) announced on Monday (4) an update of the provisional guidance on breastfeeding in the context of zika. As already announced in the first version of the guide, released in February this year, there is no evidence that the virus is transmitted during lactation. Therefore, mothers with suspected infection, probable or confirmed should continue breastfeeding their babies normally. The WHO recommendation is that, within an hour after birth, mothers initiate breastfeeding; infants should be fed exclusively on breast milk until six months of age. From that period, breastfeeding must remain up to two years of age or older, with the timely introduction of other adequate and safe food. Mothers and families of babies born with congenital abnormalities, such as microcephaly, should also be supported to breastfeed their babies in accordance with the recommendations of PAHO / WHO.

Overview of Zika virus (ZIKV) infection in regards to the Brazilian epidemic.

Zika virus (ZIKV), a mosquito-borne flavivirus, belongs to the Flaviviridae family, genus Flavivirus. ZIKV was initially isolated in 1947 from a sentinel monkey in the Zika forest, Uganda. Little clinical importance was attributed to ZIKV, once only few symptomatic cases were reported in some African and Southeast Asiatic countries. This situation changed in 2007, when a large outbreak was registered on the Yap Island, Micronesia, caused by the Asian ZIKV lineage. Between 2013 and 2014, ZIKV spread explosively and caused many outbreaks in different islands of the Southern Pacific Ocean and in 2015 autochthonous transmission was reported in Brazil. Currently, Brazil is the country with the highest number of ZIKV-positive cases in Latin America. Moreover, for the first time after the discovery of ZIKV, the Brazilian scientists are studying the possibility for the virus to cause severe congenital infection related to microcephaly and serious birth defects due to the time-spatial coincidence of the alarming increase of newborns with microcephaly and the Brazilian ZIKV epidemic. The present review summarizes recent information for ZIKV epidemiology, clinical picture, transmission, diagnosis and the consequences of this emerging virus in Brazil.

Protocolo de vigilância e resposta à ocorrência de microcefalia e/ou alterações do sistema nervoso central (SNC) / Protocol for surveillance and response to the occurrence of microcephaly and / or central nervous system (CNS) alterations / Protocolo de vigilancia y respuesta a la ocurrencia de casos de microcefalia y/o alteraciones del sistema nervioso central (SNC)

Este protocolo tem como objetivo prover os profissionais de saúde e áreas técnicas de vigilância em saúde com informações gerais, orientações técnicas e diretrizes relacionadas às ações de vigilância de microcefalias e/ou alterações do sistema nervoso central (SNC) sugestivas de infecção congênita em todo território nacional. Deve ser ressaltado que as informações e recomendações aqui presentes e agora divulgadas foram fundamentadas e estabelecidas a partir das discussões conduzidas entre áreas técnicas do Ministério da Saúde do Brasil e especialistas de diversas áreas da medicina, epidemiologia, estatística, geografia e laboratório, além de representantes das Secretarias de Saúde de Estados e Municípios afetados. O Sistema Único de Saúde (SUS) avança para elucidação desse evento e a cada dia acumula novas evidências a partir das investigações realizadas desde outubro de 2015,quando o Ministério da Saúde recebeu as primeiras notificações da Secretaria de Saúde do Estado de Pernambuco. Essa evidências passam pelo reconhecimento da relação entre a presença do vírus e a ocorrência de microcefalias e óbitos, a comprovação de que o vírus atravessa a barreira placentária, a identificação do vírus Zika em natimortos e recém-nascidos com microcefalia e/ou outras malformações do SNC, dentre outras. Esse reconhecimento é inédito na literatura nacional e internacional e só foi possível pelo empenho...

Overview of Zika virus (ZIKV) infection in regards to the Brazilian epidemic

Zika virus (ZIKV), a mosquito-borne flavivirus, belongs to the Flaviviridae family, genus Flavivirus. ZIKV was initially isolated in 1947 from a sentinel monkey in the Zika forest, Uganda. Little clinical importance was attributed to ZIKV, once only few symptomatic cases were reported in some African and Southeast Asiatic countries. This situation changed in 2007, when a large outbreak was registered on the Yap Island, Micronesia, caused by the Asian ZIKV lineage. Between 2013 and 2014, ZIKV spread explosively and caused many outbreaks in different islands of the Southern Pacific Ocean and in 2015 autochthonous transmission was reported in Brazil. Currently, Brazil is the country with the highest number of ZIKV-positive cases in Latin America. Moreover, for the first time after the discovery of ZIKV, the Brazilian scientists are studying the possibility for the virus to cause severe congenital infection related to microcephaly and serious birth defects due to the time-spatial coincidence of the alarming increase of newborns with microcephaly and the Brazilian ZIKV epidemic. The present review summarizes recent information for ZIKV epidemiology, clinical picture, transmission, diagnosis and the consequences of this emerging virus in Brazil.