Association between Zika virus and fetopathy: a prospective cohort study in French Guiana

Pathological characterization of female reproductive organs prior to miscarriage induced by Zika virus infection in the pregnant common marmoset

While Zika virus (ZIKV) infection in pregnant women is known to increase the risk of miscarriage and stillbirth, the mechanism by which ZIKV infection leads to the inability to continue a pregnancy is not clear. In our common marmoset models of ZIKV infection in pregnant individuals, miscarriage was observed in dams infected in the first or second trimester, and preterm delivery was observed in a dam infected in the third trimester. Serum progesterone levels were significantly lower prior to miscarriage or preterm delivery in the infected marmosets. To elucidate the pathology of the placental region just before the onset of ZIKV-induced miscarriage, we newly prepared an infected marmoset in the first trimester of pregnancy and euthanized it when the serum progesterone concentration was markedly reduced. Pathological analysis revealed significant degeneration in cells at the maternal-fetal interface, presumably trophoblasts. Cleaved-caspase was widely observed in the endometrial to placental region, and TNFα at 200 pg/mL was detected in the amniotic fluid, suggesting that apoptosis may progress in the endometrium and placenta, leading to decreased trophoblast function and miscarriage. ZIKV NS1 protein was found sporadically in the cellular degeneration area and widely in the basal layer of the endometrium. Furthermore, the viral protein was frequently detected in the follicles and corpus luteum of the ovary. The developed ZIKV infection model in pregnant marmosets would be useful not only to better understand the mechanism of ZIKV-induced miscarriage but also to analyze the effects of the viral infection on female reproductive tissues.

IMPORTANCE

Although several viruses, including Zika virus (ZIKV), are known to increase the risk of miscarriage upon viral infection, the mechanism by which miscarriage is induced by viral infection is largely unknown. This is partly due to the difficulty of pathological analysis of maternal tissues in the period following viral infection and prior to miscarriage. In this study, we predicted the occurrence of miscarriage by monitoring serum progesterone levels and performed pathological analysis of peri-placental tissues at a time point assumed to be just before miscarriage. This is the first report of trophoblast degeneration prior to miscarriage, suggesting that the experimental method used here is useful for analyzing the pathogenesis of virus infection-related miscarriage. Further immunostaining revealed that ZIKV NS1 was distributed not only in the uterus but also in the ovaries, with particularly pronounced staining of oocytes. Whether ZIKV infection affects female reproductive function should be clarified in the future.

Neonatal Microcephaly and Central Nervous System Abnormalities During the Zika Outbreak in Rio de Janeiro

This retrospective cohort study analyzed 7870 pregnant women, including 2269 with confirmed Zika virus (ZIKV) infection and 5601 without Zika infection, along with their fetuses and newborns. Data were sourced from multiple databases in the state of Rio de Janeiro, Brazil. A propensity score model was employed to control confounding factors and stratify outcomes by pregnancy trimester. Among ZIKV+ pregnant women, 49 cases of congenital microcephaly or congenital nervous system (CNS) abnormalities were identified (2.16%, or 193.9 cases in 10,000 live births), whereas 44 cases were identified among ZIKV- women (0.78%, or 71.4 cases in 10,000 live births). Multivariable analysis yielded an odds ratio of 2.46 (95% CI 1.30-4.64) overall, with 4.29 (95% CI 1.93-9.53) in the first trimester, 5.29 (95% CI 1.08-25.95) in the second trimester, and 0.68 (95% CI 0.21-2.14) in the third trimester. The most frequent findings among ZIKV+ cases included intracranial calcifications, ventriculomegaly, posterior fossa malformations, reduced brain volume, corpus callosum malformations, cortex dysplasia, lissencephaly, and pachygyria. Ophthalmologic abnormalities were detected in 55.5% of cases, and brainstem auditory evoked potential anomalies were reported in 33.3%. ZIKV infection can result in structural or functional anomalies. Given the absence of specific treatment for congenital Zika syndrome (CZS), clinical care should prioritize monitoring and managing neurological, motor, auditory, visual, and orthopedic disorders in all children with in utero ZIKV exposure, especially during the first and second trimesters of pregnancy.

Prenatal and Postnatal Ocular Abnormalities Following Congenital Zika Virus Infections: A Systematic Review

OBJECTIVE

To assess fetal and neonatal eyes abnormalities and their progression during the last ZIKV outbreak and summarize learned lessons.

METHODS

A systematic review and meta-analysis was conducted by a team of obstetricians and ophthalmologists.

RESULTS

Studies reporting ocular abnormalities during the prenatal (n = 5) and postnatal (n = 24) periods were included in the analysis. In the prenatal period, the most common ocular findings were intraocular calcification cases (4/6, 66.6%) and microphthalmia (3/6, 50%). Postnatal ocular abnormalities of congenital ZIKV infection were described after birth in 479 cases. Among them microphthalmia was reported in 13 cases (13/479, 2.7%). Posterior segment (retina and optic nerve) was the most affected structure, consisting of pigmentary changes (229/479, 47.8%), macular chorioretinal atrophy (216/479, 45%), optic nerve atrophy (181/479, 37.8%), increased cup-to-disk ratio (190/479, 39.6.%), optic nerve hypoplasia (93/479,19.4%), vascular changes (26/479, 5.4%), and retinal coloboma (20/479, 4.1%). The anterior segment was involved in 4.6% (22/479) of cases, including cataract (9/479, 1.8%), lens subluxation (1/479, 0.2%), iris coloboma (5/479, 1%), and congenital glaucoma (7/479, 1.4%). These ocular anomalies were isolated in one case (1/479, 0.2%) and multiple anomalies were found in the other cases. Long-term visual disorders have been described, with no possible improvement and even a worsening of some of the ocular anomalies previously observed. No reactivation of ocular lesions was observed.

CONCLUSION

This review highlights the severe ocular abnormalities associated with congenital ZIKV infections. The importance of multidisciplinary communication between the obstetrician, the maternal-fetal medicine specialist, and the ophthalmologist is emphasized.

PROTOCOL REGISTRATION

This systematic review was registered with the International Prospective Register of Systematic Reviews (PROSPERO), registration440 188.

Emerging and re-emerging infectious diseases in pregnant women in an amazonian region: a large retrospective study from French Guiana

PURPOSE

Over the past decade, the Amazon basin has faced numerous infectious epidemics. Our comprehension of the actual extent of these infections during pregnancy remains limited. This study aimed to clarify the clinical and epidemiological features of emerging and re-emerging infectious diseases during pregnancy in western French Guiana and along the Maroni River over the previous nine years.

METHODS

This retrospective cohort study enrolled pregnant women living in west French Guiana territory and giving birth in the only local referral center after 22 weeks of gestation between 2013 and 2021. Data on symptomatic or asymptomatic biologically confirmed emerging or re-emerging diseases during pregnancy was collected.

RESULTS

Six epidemic waves were experienced during the study period, including 498 confirmed Zika virus infections (2016), 363 SARS-CoV-2 infections (2020-2021), 87 chikungunya virus infections (2014), 76 syphilis infections (2013-2021), and 60 dengue virus infections (2013-2021) at different gestational ages. Furthermore, 1.1% (n = 287) and 1.4% (n = 350) of pregnant women in west French Guiana were living with HIV and HTLV, respectively. During the study period, at least 5.5% (n = 1,371) faced an emerging or re-emerging infection during pregnancy.

CONCLUSION

These results highlight the diversity, abundance, and dynamism of emerging and re-emerging infectious agents faced by pregnant women in the Amazon basin. Considering the maternal and neonatal adverse outcomes associated with these infections, increased efforts are required to enhance diagnosis, reporting, and treatment of these conditions.

High-Risk Areas for Congenital Zika Syndrome in Rio de Janeiro: Spatial Cluster Detection

Brazil reported 18,282 suspected congenital Zika syndrome (CZS) cases up to 2018 and accounts for 61.4% of the total reported Zika cases in the Americas in the period. To detect high-risk areas for children with CZS in the city of Rio de Janeiro, we used cluster detection and thematic maps. We analyzed data using a Poisson model in Satscan 10.1.3 software. We also analyzed the records of children with CZS from 2015 to 2016 to describe the clinical and epidemiological maternal and child profile, as well as live births in 2016 and the social development index (SDI) by neighborhood. In 2015 and 2016, the incidence rates of CZS were 8.84 and 46.96 per 100,000 live births in the city, respectively. Severe congenital findings such as microcephaly and brain damage, osteoarticular impairment, ocular abnormalities, and hearing loss were observed in 47 children. The spatial distribution of CZS was concentrated in the north and west zones in heterogeneous neighborhoods. The neighborhoods with the highest occurrence of CZS cases were found to have the worst SDIs. Stascan detected three spatial clusters in the north zone, where the SDI is lower. The clusters presented high relative risks for CZS (7.86, 1.46, and 2.08), although they were not statistically significant. Our findings highlight a higher occurrence of CZS in areas with less favorable socioeconomic conditions.

Arboviruses and pregnancy: are the threats visible or hidden?

Mosquito-borne arboviral diseases are a global concern and can have severe consequences on maternal, neonatal, and child health. Their impact on pregnancy tends to be neglected in developing countries. Despite hundreds of millions of infections, 90% pregnancies being exposed, scientific data on pregnant women is poor and sometimes non-existent. Recently and since the 2016 Zika virus outbreak, there has been a newfound interest in these diseases. Through various neuropathogenic, visceral, placental, and teratogenic mechanisms, these arbovirus infections can lead to fetal losses, obstetrical complications, and a wide range of congenital abnormalities, resulting in long-term neurological and sensory impairments. Climate change, growing urbanization, worldwide interconnectivity, and ease of mobility allow arboviruses to spread to other territories and impact populations that had never been in contact with these emerging agents before. Pregnant travelers are also at risk of infection with potential subsequent complications. Beyond that, these pathologies show the inequalities of access to care on a global scale in a context of demographic growth and increasing urbanization. It is essential to promote research, diagnostic tools, treatments, and vaccine development to address this emerging threat.Background The vulnerability of pregnant women and fetuses to emergent and re-emergent pathogens has been notably illustrated by the outbreaks of Zika virus. Our comprehension of the complete scope and consequences of these infections during pregnancy remains limited, particularly among those involved in perinatal healthcare, such as obstetricians and midwives. This review aims to provide the latest information and recommendations regarding the various risks, management, and prevention for pregnant women exposed to arboviral infections.

Contrasted life trajectories: reconstituting the main population exposomes in French Guiana

In French Guiana, life expectancy is between 2 and 3 years below that of France, reflecting differences in mortality rates that are largely sensitive to primary healthcare and thus preventable. However, because poverty affects half of the population in French Guiana, global measurements of life expectancy presumably conflate at least two distinct situations: persons who have similar life expectancies as in mainland France and persons living in precariousness who have far greater mortality rates than their wealthier counterparts. We thus aimed to synthesize what is known about statistical regularities regarding exposures and sketch typical French Guiana exposomes in relation to health outcomes. We conducted a narrative review on common exposures in French Guiana and made comparisons between French Guiana and mainland France, between rich and poor in French Guiana, and between urban and rural areas within French Guiana. The most striking fact this panorama shows is that being a fetus or a young child in French Guiana is fraught with multiple threats. In French Guiana, poverty and poor pregnancy follow-up; renouncing healthcare; wide variety of infectious diseases; very high prevalence of food insecurity; psychosocial stress; micronutrient deficiencies; obesity and metabolic problems; and frequent exposure to lead and mercury in rural areas constitute a stunningly challenging exposome for a new human being to develop into. A substantial part of the population's health is hence affected by poverty and its sources of nutrition.

Causes and consequences of fever in Amazonian pregnant women: A large retrospective study from French Guiana

OBJECTIVE

The aim of this study was to describe different causes and consequences of fever during pregnancy in Western French Guiana and along the Maroni River.

STUDY DESIGN

A retrospective single-center study including all patients with a history of documented fever ≥ 38°C during pregnancy at the West French Guiana Hospital for 9 years. Postpartum fever and nosocomial infections were excluded. We focused on medical history and on clinical and biological findings. Causes were characterized as confirmed or uncertain and then classified as preventable or non-preventable.

RESULTS

A total of 940 pregnant women who experienced at least one episode of fever were included and compared to 23,811 deliveries who occurred during the same period without documented fever. Among them, 43.7% (411/940) were in labor. About 3.7% (35/940) of febrile pregnant women had at least two episodes of fever, while 0.3% (3/940) had a coinfection at the time of diagnosis, resulting in a total of 978 febrile episodes. Among them, causes remained unknown or uncertain in 7.6% (75/978) and 0.9% (9/978) of cases, respectively. Among confirmed causes of fever throughout pregnancy (n = 483), the most common known cause was arbovirus infection (146/483, 30.2%), followed by urinary tract infection (134/483, 27.7%), chickenpox (27/483, 5.6%), and gastrointestinal (14/483, 2.9%) and pulmonary infections (10/483, 2%). Mothers with fever had a higher risk of cesarean section (19.8% vs 15.5%, aOR 1.3 [95% CI 1.14-1.6], stillbirth (5.5% versus 1.9%, aOR 2.7 [95% CI 2-3.7]), and preterm delivery < 34 weeks of gestation (7.2% vs 4.7%, aOR 1.5 [95% CI 1.2-2].

CONCLUSIONS

In the Amazon region, causes of fever are diverse and often associated with epidemic waves, notably arboviruses. This must be considered when exploring possible causes of fever during pregnancy in these localities, including fetal anomalies and/or fetal loss. Physicians should consider the epidemiological context and avoid generalizations. Given the impact of emergent agents such as arboviruses on pregnancy, particular attention must be paid to the epidemiological context. This study can also help clinicians when managing fever in pregnant travelers or in their partner after having visited exposed areas. In this context, fetal abnormalities and adverse obstetric outcomes should be explored accordingly.

Developing brain under renewed attack: viral infection during pregnancy

Living in a globalized world, viral infections such as CHIKV, SARS-COV-2, and ZIKV have become inevitable to also infect the most vulnerable groups in our society. That poses a danger to these populations including pregnant women since the developing brain is sensitive to maternal stressors including viral infections. Upon maternal infection, the viruses can gain access to the fetus via the maternofetal barrier and even to the fetal brain during which factors such as viral receptor expression, time of infection, and the balance between antiviral immune responses and pro-viral mechanisms contribute to mother-to-fetus transmission and fetal infection. Both the direct pro-viral mechanisms and the resulting dysregulated immune response can cause multi-level impairment in the maternofetal and brain barriers and the developing brain itself leading to dysfunction or even loss of several cell populations. Thus, maternal viral infections can disturb brain development and even predispose to neurodevelopmental disorders. In this review, we discuss the potential contribution of maternal viral infections of three relevant relative recent players in the field: Zika, Chikungunya, and Severe Acute Respiratory Syndrome Coronavirus-2, to the impairment of brain development throughout the entire route.

Maternal Zika Virus Infection in the First Trimester and Fetal Stigmata in the Third Trimester

Zika is a flavivirus that is transmitted primarily by the bite of an infected Aedes mosquito. It can also be transmitted by blood transfusion, sexual contact, and from an infected mother to the unborn baby. Zika virus infection is of particular concern in pregnancy as transplacental transmission of the virus has the potential to cause significant fetal morbidity. Ultrasonography plays a pivotal role in the fetal surveillance of a pregnant woman infected with Zika. There have been outbreaks of Zika virus infection in various parts of India, the most recent occurring in Kanpur in November 2021. We report a case of a primigravida who had Zika virus infection during the first trimester of pregnancy but the fetus presented with the sequelae of infection in the third trimester. This report highlights the sonographic red flags for fetal Zika infection and the importance of serial monitoring in pregnant women exposed to Zika virus.

Dengue, chikungunya and zika arbovirus infections in Caribbean children

PURPOSE OF REVIEW

Dengue, chikungunya and zika have caused significant epidemics in the Caribbean in recent years. This review highlights their impact in Caribbean children.

RECENT FINDINGS

Dengue has been increasingly intense and severe, seroprevalence is 80-100% in the Caribbean, children have increased attributable morbidity and mortality. Severe dengue, especially dengue with haemorrhage was significantly associated with haemoglobin SC disease and multiple organ-systems involved. These included the gastrointestinal and haematologic systems with extremely high lactate dehydrogenases and creatinine phosphokinases and severely abnormal bleeding indices. Despite appropriate interventions, mortality was highest within the first 48 h of admission. Chikungunya, a togavirus, affected 80% of some Caribbean populations. Paediatric presentations included high fever, skin, joint and neurological manifestations. Children less than 5 years of age had the highest morbidity and mortality. This maiden chikungunya epidemic was explosive and overwhelmed public health systems. Zika, another flavivirus, has a seroprevalence of 15% in pregnancy, so the Caribbean remains susceptible. Paediatric complications include pregnancy losses, stillbirths, Congenital Zika syndrome, Guillain-Barre syndrome, acute disseminated encephalomyelitis and transverse myelitis. Neurodevelopment stimulation programs for zika-exposed infants have been effective in improving language and positive behaviour scores.

SUMMARY

Caribbean children remain at risk for dengue, chikungunya and zika, with high attributable morbidity and mortality.

Maternal immune activation as an epidemiological risk factor for neurodevelopmental disorders: Considerations of timing, severity, individual differences, and sex in human and rodent studies

Epidemiological evidence suggests that one's risk of being diagnosed with a neurodevelopmental disorder (NDD)-such as autism, ADHD, or schizophrenia-increases significantly if their mother had a viral or bacterial infection during the first or second trimester of pregnancy. Despite this well-known data, little is known about how developing neural systems are perturbed by events such as early-life immune activation. One theory is that the maternal immune response disrupts neural processes important for typical fetal and postnatal development, which can subsequently result in specific and overlapping behavioral phenotypes in offspring, characteristic of NDDs. As such, rodent models of maternal immune activation (MIA) have been useful in elucidating neural mechanisms that may become dysregulated by MIA. This review will start with an up-to-date and in-depth, critical summary of epidemiological data in humans, examining the association between different types of MIA and NDD outcomes in offspring. Thereafter, we will summarize common rodent models of MIA and discuss their relevance to the human epidemiological data. Finally, we will highlight other factors that may interact with or impact MIA and its associated risk for NDDs, and emphasize the importance for researchers to consider these when designing future human and rodent studies. These points to consider include: the sex of the offspring, the developmental timing of the immune challenge, and other factors that may contribute to individual variability in neural and behavioral responses to MIA, such as genetics, parental age, the gut microbiome, prenatal stress, and placental buffering.

Fetuses and infants with Amyoplasia congenita in congenital Zika syndrome: The evidence of a viral cause. A narrative review of 144 cases

OBJECTIVES

Amyoplasia congenita is the most frequent type of arthrogryposis causing fetal hypokinesia, leading to congenital contractures at birth. The pathogenesis is thought to be impaired blood circulation to the fetus early in pregnancy, with hypotension and hypoxia damaging the anterior horn cells. In animal studies however a prenatal infection with a poliomyelitis-like viral agent was demonstrated. Congenital Zika virus syndrome (CZVS) has recently been described in infants with severe microcephaly, and in 10-25% of cases arthrogryposis.

METHODS

A search in PubMed for CZVS yielded 124 studies. After a selection for arthrogryposis, 35 papers were included, describing 144 cases. The studies were divided into two categories. 1) Those (87 cases) focussing on imaging or histological data of congenital brain defects, contained insufficient information to link arthrogryposis specifically to lesions of the brain or spinal motor neuron. 2) In the other 57 cases detailed clinical data could be linked to neurophysiological, imaging or histological data.

RESULTS

In category 1 the most frequent brain abnormalities in imaging studies were ventriculomegaly, calcifications (subcortical, basal ganglia, cerebellum), hypoplasia of the brainstem and cerebellum, atrophy of the cerebral cortex, migration disorders and corpus callosum anomalies. In category 2, in 38 of 57 cases clinical data were indicative of Amyoplasia congenita. This diagnosis was confirmed by electromyographic findings (13 cases), by MRI (37 cases) or histology (12 cases) of the spinal cord. The latter showed small or absent lateral corticospinal tracts, and cell loss and degeneration of motor neuron cells. Zika virus-proteins and flavivirus-like particles were detected in cytoplasm of spinal neurons.

CONCLUSION

The phenotype of arthrogryposis in CZVS is consistent with Amyoplasia congenita. These findings warrant search for an intrauterine infection with any neurotropic viral agent with affinity to spinal motor neurons in neonates with Amyoplasia.

Monkeypox and Pregnancy: Latest Updates

Monkeypox virus (MPXV) has emerged as a threatening zoonosis. Its spread around the world has been growing fast over the last 2 years, particularly in 2022. The reasons for this sudden spread are probably multifactorial. The R0 values of the two MPXV clades are rather low, and a massive pandemic is considered unlikely, although the increase in the number of single-nucleotide polymorphisms found in the 2022 MPXV strain could indicate an accelerated human adaptation. Very little is known about the risks of an infection during pregnancy for both the mother and the fetus. Further observations must be made to create clear, adapted, evidence-based guidelines. This article summarizes the current knowledge about MPXV infections and similar pregnancy virus infections.

Prevalence of microcephaly and Zika virus infection in a pregnancy cohort in Kenya, 2017-2019

BACKGROUND

Zika virus (ZIKV), first discovered in Uganda in 1947, re-emerged globally in 2013 and was later associated with microcephaly and other birth defects. We determined the incidence of ZIKV infection and its association with adverse pregnancy and fetal outcomes in a pregnancy cohort in Kenya.

METHODS

From October 2017 to July 2019, we recruited and followed up women aged ≥ 15 years and ≤ 28 weeks pregnant in three hospitals in coastal Mombasa. Monthly follow-up included risk factor questions and a blood sample collected for ZIKV serology. We collected anthropometric measures (including head circumference), cord blood, venous blood from newborns, and any evidence of birth defects. Microcephaly was defined as a head circumference (HC) < 2 standard deviations (SD) for sex and gestational age. Severe microcephaly was defined as HC < 3 SD for sex and age. We tested sera for anti-ZIKV IgM antibodies using capture enzyme-linked immunosorbent assay (ELISA) and confirmed positives using the plaque reduction neutralization test (PRNT₉₀) for ZIKV and for dengue (DENV) on the samples that were ZIKV neutralizing antibody positive. We collected blood and urine from participants reporting fever or rash for ZIKV testing.

RESULTS

Of 2889 pregnant women screened for eligibility, 2312 (80%) were enrolled. Of 1916 recorded deliveries, 1816 (94.6%) were live births and 100 (5.2%) were either stillbirths or spontaneous abortions (< 22 weeks of gestation). Among 1236 newborns with complete anthropometric measures, 11 (0.9%) had microcephaly and 3 (0.2%) had severe microcephaly. A total of 166 (7.2%) participants were positive for anti-ZIKV IgM, 136 of whom became seropositive during follow-up. Among the 166 anti-ZIKV IgM positive, 3 and 18 participants were further seropositive for ZIKV and DENV neutralizing antibodies, respectively. Of these 3 and 18 pregnant women, one and 13 (72.2%) seroconverted with antibodies to ZIKV and DENV, respectively. All 308 samples (serum and urine samples collected during sick visits and samples that were anti-ZIKV IgM positive) tested by RT-PCR were negative for ZIKV. No adverse pregnancy or neonatal outcomes were reported among the three participants with confirmed ZIKV exposure. Among newborns from pregnant women with DENV exposure, four (22.2%) were small for gestational age and one (5.6%) had microcephaly.

CONCLUSIONS

The prevalence of severe microcephaly among newborns in coastal Kenya was high relative to published estimates from facility-based studies in Europe and Latin America, but little evidence of ZIKV transmission. There is a need for improved surveillance for microcephaly and other congenital malformations in Kenya.

About the need to address pediatric health inequalities in French Guiana : a scoping review

INTRODUCTION

French Guiana is a French overseas territory in South America, marked by poverty and inequalities. Access to different services, including healthcare, is unequal depending on where people live. Several studies showed that among adults, the most precarious individuals had greater incidences of chronic and infectious diseases. Although the median age of the population living in this territory is 25, there is no specific focus on the pediatric population although it is documented that socioeconomic inequalities have an impact on child health. The objective of this scoping review is to shed light on health challenges concerning children living in French Guiana.

METHODS

A literature search was performed on PubMed to identify relevant articles, and additional references were added if within the scope of this review.

RESULTS

A total of 106 publications were reviewed. Perinatal health issues were linked to a high rate of teenage pregnancies with poor medical follow-up leading to complications such as preterm deliveries and congenital malformations and abnormalities. Infectious diseases were a significant burden with worrisome vaccination coverage figures for some bacterial infections, partly explaining a high mortality rate attributable to infectious diseases. Herbicide poisoning with paraquat was reported in children, and environment-related concerns such as wild animal attacks as well as lead and mercury exposure were reported. Some children living in remote Amerindian communities had a higher suicide rate than in mainland France, and chronic diseases such as sickle cell disease were reported to have more transfusion-related complications.

CONCLUSION

Children living in French Guiana have worse pediatric health indicators in comparison with children from mainland France.

Zika virus impacts extracellular vesicle composition and cellular gene expression in macaque early gestation trophoblasts

Zika virus (ZIKV) infection at the maternal-placental interface is associated with adverse pregnancy outcomes including fetal demise and pregnancy loss. To determine how infection impacts placental trophoblasts, we utilized rhesus macaque trophoblast stem cells (TSC) that can be differentiated into early gestation syncytiotrophoblasts (ST) and extravillous trophoblasts (EVT). TSCs and STs, but not EVTs, were highly permissive to productive infection with ZIKV strain DAK AR 41524. The impact of ZIKV on the cellular transcriptome showed that infection of TSCs and STs increased expression of immune related genes, including those involved in type I and type III interferon responses. ZIKV exposure altered extracellular vesicle (EV) mRNA, miRNA and protein cargo, including ZIKV proteins, regardless of productive infection. These findings suggest that early gestation macaque TSCs and STs are permissive to ZIKV infection, and that EV analysis may provide a foundation for identifying non-invasive biomarkers of placental infection in a highly translational model.

Experimental evidence for a high rate of maternal-fetal transmission of dengue virus in the presence of antibodies in immunocompromised mice

Background

Congenital disorders associated with prenatal vertical transmission of Zika virus (ZIKV) is well established since the 2016 outbreak in the Americas. However, despite clinical reports of similar mode of transmission for other flaviviruses such as dengue virus (DENV), the phenomenon has not been experimentally explored.

Methods

Pregnant AG129 mice were infected with DENV1 in the presence or absence of enhancing antibodies at different gestational time points. ZIKV was used for comparison. We quantified viral load in fetus and placentas and performed comprehensive gene expression profiling in the maternal (decidua) and fetal portion of placenta separately.

Findings

We demonstrate in a laboratory experimental setting that DENV can be transmitted vertically in a gestation stage-dependent manner similar to ZIKV, and this incidence drastically increases in the presence of enhancing antibodies. Interestingly, a high rate of DENV fetal infection occurs even though the placental viral load is significantly lower than that found in ZIKV-infected dams. Comprehensive gene expression profiling revealed DENV infection modulates a variety of inflammation-associated genes comparable to ZIKV in decidua and fetal placenta in early pregnancy.

Interpretation

Our findings suggest that the virus-induced modulation of host gene expression may facilitate DENV to cross the placental barrier in spite of lower viral burden compared to ZIKV. This mouse model may serve to identify the host determinants required for the vertical transmission of flaviviruses and develop appropriate countermeasures.

Funding

National Medical Research Council/Open Fund Individual Research Grant MOH-000524 (SW), MOH-000086 and OFIRG20nov-0017 (SGV).

Acute neurologic emerging flaviviruses

The COVID-19 pandemic has shed light on the challenges we face as a global society in preventing and containing emerging and re-emerging pathogens. Multiple intersecting factors, including environmental changes, host immunological factors, and pathogen dynamics, are intimately connected to the emergence and re-emergence of communicable diseases. There is a large and expanding list of communicable diseases that can cause neurological damage, either through direct or indirect routes. Novel pathogens of neurotropic potential have been identified through advanced diagnostic techniques, including metagenomic next-generation sequencing, but there are also known pathogens which have expanded their geographic distribution to infect non-immune individuals. Factors including population growth, climate change, the increase in animal and human interface, and an increase in international travel and trade are contributing to the expansion of emerging and re-emerging pathogens. Challenges exist around antimicrobial misuse giving rise to antimicrobial-resistant infectious neurotropic organisms and increased susceptibility to infection related to the expanded use of immunomodulatory treatments. In this article, we will review key concepts around emerging and re-emerging pathogens and discuss factors associated with neurotropism and neuroinvasion. We highlight several neurotropic pathogens of interest, including West Nile virus (WNV), Zika Virus, Japanese Encephalitis Virus (JEV), and Tick-Borne Encephalitis Virus (TBEV). We emphasize neuroinfectious diseases which impact the central nervous system (CNS) and focus on flaviviruses, a group of vector-borne pathogens that have expanded globally in recent years and have proven capable of widespread outbreak.

Fetal central nervous system anomalies according to RT-PCR and trimester of maternal infection with Zika virus: A prospective cohort study

INTRODUCTION

In October 2015, an epidemic of Zika began in Colombia's geographic areas with a high population of mosquitoes of the genus Aedes. We aimed to describe the fetal brain ultrasound findings in pregnant women with active symptoms or a history of symptoms suggestive of Zika virus (ZIKV) infection.

MATERIAL AND METHODS

Eligible pregnant women were tested with reverse transcriptase-polymerase chain reaction (RT-PCR) for ZIKV and followed prospectively using detailed anatomic ultrasound and transvaginal neurosonography to detect structural anomalies of the fetal central nervous system (CNS).

RESULTS

A total of 115 symptomatic women with a positive ZIKV RT-PCR and 55 with a negative ZIKV RT-PCR were enrolled in the study; CNS compromise of the fetus occurred in 22% and 17%, respectively (p = 0.255). Callosal dysgenesis (14.5%) was the most frequent anomaly of the CNS, followed by microcephaly (13.6%) and neuronal migration disorders (8.3%). When symptomatic ZIKV RT-PCR-positive women were categorized by trimester of infection, CNS anomalies were present in 40% of first-trimester infections, compared with 21% and 7% in second- and third-trimester infections (p = 0.002). CNS anomalies were also more severe in first-trimester-infected fetuses than in second- and third-trimester-infected fetuses. The high prevalence of CNS anomalies in fetuses of symptomatic ZIKV RT-PCR negative women suggests a high rate of false-negative cases and an even higher prevalence of CNS anomalies than observed in this study.

CONCLUSIONS

The prevalence of fetal CNS anomalies was higher than previously reported in the literature for both symptomatic RT-PCR-positive and -negative pregnant women. Corpus callosum anomalies, microcephaly, neuronal migration disorders, and brain parenchymal hyperechogenicities were the most frequent CNS anomalies detected. In addition, CNS anomalies were more frequent and severe in infected fetuses during the first trimester of pregnancy than during the second or third trimester.

Zika virus infection in pregnant women and their children: A review

Zika virus (ZIKV) is an arthropod-borne virus (arbovirus) transmitted primarily by Aedes mosquitoes. ZIKV can be transmitted to humans by non-vector borne mechanisms such as sexual intercourse, maternal-foetal transmission or blood transfusion. In 2015, ZIKV emerged in the Americas, and spread to 87 countries and territories with autochthonous transmission, distributed across four of the six WHO regions. Most ZIKV infections in pregnancy are asymptomatic, but mother to child transmission of the virus can occur in 20 to 30% of cases and cause severe foetal and child defects. Children exposed to ZIKV while in utero might develop a pattern of structural anomalies and functional disabilities secondary to central nervous system damage, known as congenital Zika syndrome, and whose most common clinical feature is microcephaly. Normocephalic children born to mothers with ZIKV infection in pregnancy, and with no observable Zika-associated birth defects, may also present with later neurodevelopmental delay or post-natal microcephaly. Screening and detection of ZIKV infection in pregnancy is essential, because most women with ZIKV infection are asymptomatic and clinical manifestations are non-specific. However, the diagnosis of ZIKV infection poses multiple challenges due to limited resources and scarce laboratory capabilities in most affected areas, the narrow window of time that the virus persists in the bloodstream, the large proportion of asymptomatic infections, and the cross-reactivity with other flaviviruses such as Dengue virus (DENV). Molecular methods (RT-PCR) are the most reliable tool to confirm ZIKV infection, as serodiagnosis requires confirmation with neutralization tests in case of inconclusive or positive serology results. Prenatal ultrasound assessment is essential for monitoring foetal development and early detection of possible severe anomalies. A mid- and long-term follow-up of children exposed to ZIKV while in utero is necessary to promptly detect clinical manifestations of possible neurological impairment. Tweetable abstract: Zika virus infection during pregnancy is a cause of pregnancy loss and disability in children. Protection against mosquito bites, access to sexual and reproductive health services, prompt screening and detection of ZIKV infection in pregnancy, and prenatal ultrasound monitoring are key control strategies whilst a vaccine is not available.

Embryonic Stage of Congenital Zika Virus Infection Determines Fetal and Postnatal Outcomes in Mice

Zika virus (ZIKV) infection during pregnancy causes a wide spectrum of congenital abnormalities and postnatal developmental sequelae such as fetal loss, intrauterine growth restriction (IUGR), microcephaly, or motor and neurodevelopmental disorders. Here, we investigated whether a mouse pregnancy model recapitulated a wide range of symptoms after congenital ZIKV infection, and whether the embryonic age of congenital infection changed the fetal or postnatal outcomes. Infection with ZIKV strain PRVABC59 from embryonic day 6.5 (E6.5) to E8.5, corresponding to the mid-first trimester in humans, caused fetal death, fetal resorption, or severe IUGR, whereas infection from E9.5 to E14.5, corresponding to the late-first to second trimester in humans, caused stillbirth, neonatal death, microcephaly, and postnatal growth deficiency. Furthermore, 4-week-old offspring born to dams infected at E12.5 showed abnormalities in neuropsychiatric state, motor behavior, autonomic function, or reflex and sensory function. Thus, our model recapitulated the multiple symptoms seen in human cases, and the embryonic age of congenital infection was one of the determinant factors of offspring outcomes in mice. Furthermore, maternal neutralizing antibodies protected the offspring from neonatal death after congenital infection at E9.5, suggesting that neonatal death in our model could serve as criteria for screening of vaccine candidates.

Epidemiological profile of a cohort of symptomatic pregnant women with suspected Zika virus infection in the State of São Paulo, Brazil, 2015-2018

OBJECTIVE

To describe the epidemiological profile of pregnant women with suspected Zika virus infection, reported on the Center for Strategic Information for Health Surveillance System, in the state of São Paulo, Brazil, its range of abnormalities and/or pregnancy outcomes.

METHODS

Descriptive epidemiological study of a cohort of symptomatic pregnant women with suspected Zika virus infection and their pregnancy outcomes, living in the state of São Paulo, reported between 2015-2018.

RESULTS

Of the 2,329 pregnant women studied, 29.3% were confirmed to have the infection, almost half of them were single (44.8%), the majority of them were white woman (74.2%), with complete high school education (53.6%), and concentrated in the northeast region of the state. The proportion of newborns with central nervous system abnormalities was approximately 4.0%.

CONCLUSION

The results found characterize Zika virus transmission in the state of São Paulo and may support public health actions in places with higher risk of disease transmission.

Prolonged Maternal Zika Viremia as a Marker of Adverse Perinatal Outcomes

Whether prolonged maternal viremia after Zika virus infection represents a risk factor for maternal–fetal transmission and subsequent adverse outcomes remains unclear. In this prospective cohort study in French Guiana, we enrolled Zika virus–infected pregnant women with a positive PCR result at inclusion and noninfected pregnant women; both groups underwent serologic testing in each trimester and at delivery during January–July 2016. Prolonged viremia was defined as ongoing virus detection >30 days postinfection. Adverse outcomes (fetal loss or neurologic anomalies) were more common in fetuses and neonates from mothers with prolonged viremia (40.0%) compared with those from infected mothers without prolonged viremia (5.3%, adjusted relative risk [aRR] 7.2 [95% CI 0.9–57.6]) or those from noninfected mothers (6.6%, aRR 6.7 [95% CI 3.0–15.1]). Congenital infections were confirmed more often in fetuses and neonates from mothers with prolonged viremia compared with the other 2 groups (60.0% vs. 26.3% vs. 0.0%, aRR 2.3 [95% CI 0.9–5.5]).

Association between confirmed congenital Zika infection at birth and outcomes up to 3 years of life

Little is known about the long-term neurological development of children diagnosed with congenital Zika infection at birth. Here, we report the imaging and clinical outcomes up to three years of life of a cohort of 129 children exposed to Zika virus in utero. Eighteen of them (14%) had a laboratory confirmed congenital Zika infection at birth. Infected neonates have a higher risk of adverse neonatal and early infantile outcomes (death, structural brain anomalies or neurologic symptoms) than those who tested negative: 8/18 (44%) vs 4/111 (4%), aRR 10.1 [3.5–29.0]. Neurological impairment, neurosensory alterations or delays in motor acquisition are more common in infants with a congenital Zika infection at birth: 6/15 (40%) vs 5/96 (5%), aRR 6.7 [2.2–20.0]. Finally, infected children also have an increased risk of subspecialty referral for suspected neurodevelopmental delay by three years of life: 7/11 (64%) vs 7/51 (14%), aRR 4.4 [1.9–10.1]. Infected infants without structural brain anomalies also appear to have an increased risk, although to a lesser extent, of neurological abnormalities. It seems paramount to offer systematic testing for congenital ZIKV infection in cases of in utero exposure and adapt counseling based on these results.

Here, using diagnostic tools in a longitudinal cohort of ZIKV-infected pregnant women of the French Guiana Western Hospital Center (CHOG) and their infants, the authors investigate the long term neuropathological effects of congenital infection, finding that a laboratory confirmed congenital ZIKV infection at birth is associated with higher risks of adverse neurological outcomes up to three years of life.

Early Embryonic Loss Following Intravaginal Zika Virus Challenge in Rhesus Macaques

Zika virus (ZIKV) is an arthropod-borne virus (arbovirus) and is primarily transmitted by Aedes species mosquitoes; however, ZIKV can also be sexually transmitted. During the initial epidemic and in places where ZIKV is now considered endemic, it is difficult to disentangle the risks and contributions of sexual versus vector-borne transmission to adverse pregnancy outcomes. To examine the potential impact of sexual transmission of ZIKV on pregnancy outcome, we challenged three rhesus macaques (Macaca mulatta) three times intravaginally with 1 x 107 PFU of a low passage, African lineage ZIKV isolate (ZIKV-DAK) in the first trimester (~30 days gestational age). Samples were collected from all animals initially on days 3 through 10 post challenge, followed by twice, and then once weekly sample collection; ultrasound examinations were performed every 3-4 days then weekly as pregnancies progressed. All three dams had ZIKV RNA detectable in plasma on day 3 post-ZIKV challenge. At approximately 45 days gestation (17-18 days post-challenge), two of the three dams were found with nonviable embryos by ultrasound. Viral RNA was detected in recovered tissues and at the maternal-fetal interface (MFI) in both cases. The remaining viable pregnancy proceeded to near term (~155 days gestational age) and ZIKV RNA was detected at the MFI but not in fetal tissues. These results suggest that sexual transmission of ZIKV may represent an underappreciated risk of pregnancy loss during early gestation.

Is the ZIKV Congenital Syndrome and Microcephaly Due to Syndemism with Latent Virus Coinfection?

The emergence of the Zika virus (ZIKV) mirrors its evolutionary nature and, thus, its ability to grow in diversity or complexity (i.e., related to genome, host response, environment changes, tropism, and pathogenicity), leading to it recently joining the circle of closed congenital pathogens. The causal relation of ZIKV to microcephaly is still a much-debated issue. The identification of outbreak foci being in certain endemic urban areas characterized by a high-density population emphasizes that mixed infections might spearhead the recent appearance of a wide range of diseases that were initially attributed to ZIKV. Globally, such coinfections may have both positive and negative effects on viral replication, tropism, host response, and the viral genome. In other words, the possibility of coinfection may necessitate revisiting what is considered to be known regarding the pathogenesis and epidemiology of ZIKV diseases. ZIKV viral coinfections are already being reported with other arboviruses (e.g., chikungunya virus (CHIKV) and dengue virus (DENV)) as well as congenital pathogens (e.g., human immunodeficiency virus (HIV) and cytomegalovirus (HCMV)). However, descriptions of human latent viruses and their impacts on ZIKV disease outcomes in hosts are currently lacking. This review proposes to select some interesting human latent viruses (i.e., herpes simplex virus 2 (HSV-2), Epstein-Barr virus (EBV), human herpesvirus 6 (HHV-6), human parvovirus B19 (B19V), and human papillomavirus (HPV)), whose virological features and co-exposition with ZIKV may provide evidence of the syndemism process, shedding some light on the emergence of the ZIKV-induced global congenital syndrome in South America.

Reassessment of the risk of birth defects due to Zika virus in Guadeloupe, 2016

BACKGROUND

In the French Territories in the Americas (FTA), the risk of birth defects possibly associated with Zika virus (ZIKV) infection was 7.0% (95%CI: 5.0 to 9.5) among foetuses/infants of 546 women with symptomatic RT-PCR confirmed ZIKV infection during pregnancy. Many of these defects were isolated measurement-based microcephaly (i.e. without any detected brain or clinical abnormalities) or mild neurological conditions. We wanted to estimate the proportion of such minor findings among live births of women who were pregnant in the same region during the outbreak period but who were not infected with ZIKV.

METHODS

In Guadeloupe, pregnant women were recruited at the time of delivery and tested for ZIKV infection. The outcomes of live born infants of ZIKV non-infected women were compared to those of ZIKV-exposed live born infants in Guadeloupe, extracted from the FTA prospective cohort.

RESULTS

Of 490 live born infants without exposure to ZIKV, 42 infants (8.6%, 95%CI: 6.2-11.4) had mild abnormalities that have been described as 'potentially linked to ZIKV infection'; all but one of these was isolated measurement-based microcephaly. Among the 241 live born infants with ZIKV exposure, the proportion of such abnormalities, using the same definition, was similar (6.6%, 95%CI: 3.8-10.6).

CONCLUSIONS

Isolated anthropometric abnormalities and mild neurological conditions were as prevalent among infants with and without in-utero ZIKV exposure. If such abnormalities had not been considered as 'potentially linked to ZIKV' in the original prospective cohort in Guadeloupe, the overall estimate of the risk of birth defects considered due to the virus would have been significantly lower, at approximately 1.6% (95% CI: 0.4-4.1).

TRIAL REGISTRATION

ClinicalTrials.gov (NCT02916732).

Fetal, neonatal, and infant outcomes associated with maternal Zika virus infection during pregnancy: A systematic review and meta-analysis

The occurrence of fetal and neonatal disorders in pregnant women with Zika virus infection in the literature is not consistent. This study aims to estimate the prevalence rate of these disorders in fetuses/neonates of pregnant women with confirmed or probable infection by Zika virus. A systematic review with meta-analysis was conducted in November 2020. Cohort studies that contained primary data on the prevalence of unfavorable outcomes in fetuses or neonates of women with confirmed or probable Zika virus infection during pregnancy were included. A total of 21 cohort studies were included, with a total of 35,568 pregnant women. The meta-analysis showed that central nervous system abnormalities had the highest prevalence ratio of 0.06 (95% CI 0.03-0.09). Intracranial calcifications had a prevalence ratio of 0.01 (95% CI 0.01-0.02), and ventriculomegaly 0.01 (95% CI 0.01-0.02). The prevalence ratio of microcephaly was 0.03 (95% CI 0.02-0.05), fetal loss (miscarriage and stillbirth) was 0.04 (95% CI 0.02-0.06), Small for Gestational Age was 0.04 (95% CI 0.00-0,09), Low Birth Weight was 0.05 (95% CI 0.03-0.08) and Prematurity was 0.07 (95% CI 0.04-0.10). The positivity in RT-PCR for ZIKV performed in neonates born to infected mothers during pregnancy was 0.25 (95% CI 0.06-0.44). We also performed the meta-analysis of meta-analysis for microcephaly with the prevalence ratios from other two previously systematic reviews: 0.03 (95% CI 0.00-0.25). Our results contribute to measuring the impact of Zika virus infection during pregnancy on children's health. The continuous knowledge of this magnitude is essential for the implementation development of health initiatives and programs, in addition to promoting disease prevention, especially in the development of a vaccine for Zika virus. PROSPERO protocol registration: http://www.crd.york.ac.uk/PROSPERO/display_record.php?ID=CRD42019125543.

Zika virus infection in pregnant travellers and impact on childhood neurodevelopment in the first two years of life: A prospective observational study

BACKGROUND

The emergence of Zika virus (ZIKV) represents a threat with consequences on maternal and children's health. We aimed to assess the clinical and epidemiological characteristics of pregnant women returning from ZIKV affected areas, and the effects of maternal ZIKV infection on birth outcomes and children's health.

METHODS

This was a hospital-based prospective observational study conducted at the Hospital Clínic of Barcelona and Hospital Sant Joan de Déu, Barcelona, Spain, from January 2016 to February 2020.

RESULTS

One hundred and ninety-five pregnant women who had travelled to ZIKV affected areas during pregnancy were recruited. Four women (2.1%) had a confirmed ZIKV infection, 40 women (20.5%) a probable infection, and 151 (77.4%) were negative for ZIKV. Among the ZIKV confirmed cases, a pregnant woman suffered a miscarriage, highly plausible to be associated with ZIKV infection. Brain cysts and microcalcifications were detected in 7% of fetuses or infants from women with confirmed or probable ZIKV infection. Neurodevelopmental delay in the language function was found in 33.3% out of the 21 children evaluated.

CONCLUSIONS

These findings contribute to the understanding of ZIKV prevalence estimates, and the impact of maternal ZIKV infection on pregnancy outcomes and children's health. Results highlight the importance of long-term surveillance in pregnant travellers and their children.

Congenital Zika syndrome: A systematic review

BACKGROUND

The signs and symptoms of Zika virus infection are usually mild and self-limited. However, the disease has been linked to neurological complications such as Guillain-Barré syndrome and peripheral nerve involvement, and also to abortion and fetal deaths due to vertical transmission, resulting in various congenital malformations in newborns, including microcephaly. This review aimed to describe the o signs and symptoms that characterize the congenital Zika syndrome.

METHODS AND FINDINGS

A systematic review was performed with a protocol and described according to the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. The search strategy yielded 2,048 studies. After the exclusion of duplicates and application of inclusion criteria, 46 studies were included. The main signs and symptoms associated with the congenital Zika syndrome were microcephaly, parenchymal or cerebellar calcifications, ventriculomegaly, central nervous system hypoplasia or atrophy, arthrogryposis, ocular findings in the posterior and anterior segments, abnormal visual function and low birthweight for gestational age.

CONCLUSIONS

Zika virus infection during pregnancy can cause a series of changes in the growth and development of children, while impacting the healthcare system due to the severity of cases. Our findings outline the disease profile in newborns and infants and may contribute to the development and updating of more specific clinical protocols.

Zika Virus Infection in a Cohort of Pregnant Women with Exanthematic Disease in Manaus, Brazilian Amazon

The epidemic transmission of Zika virus (ZIKV) in Brazil has been identified as a cause of microcephaly and other neurological malformations in the babies of ZIKV-infected women. The frequency of adverse outcomes of Zika virus infection (ZIKVi) in pregnancy differs depending on the characteristics of exposure to infection, the time of recruitment of research participants, and the outcomes to be observed. This study provides a descriptive analysis—from the onset of symptoms to delivery—of a cohort registered as having maternal ZIKVi in pregnancy, from November 2015 to December 2016. Suspected cases were registered at a referral center for infectious and tropical diseases in Manaus, in the Amazonian region of Brazil. Of 834 women notified, 762 women with confirmed pregnancies were enrolled. Reverse-transcriptase polymerase chain reaction (RT-PCR) confirmed ZIKVi in 42.3% of the cohort. In 35.2% of the cohort, ZIKV was the sole infection identified. Severe adverse pregnancy outcomes (miscarriage, stillbirth, or microcephaly) were observed in both RT-PCR ZIKV-positive (5.0%) and ZIKV-negative (1.8%) cases (RR 3.1; 95% IC 1.4–7.3; p < 0.05), especially during the first trimester of pregnancy (RR 6.2, 95% IC 2.3–16.5; p < 0.001). Although other infectious rash diseases were observed in the pregnant women in the study, having confirmed maternal ZIKVi was the most important risk factor for serious adverse pregnancy events.

Systematic review: fetal death reporting and risk in Zika-affected pregnancies

OBJECTIVES

Zika virus is linked to several adverse pregnancy outcomes. We assessed whether Zika infection during pregnancy is associated with increased risk of foetal death (miscarriage, stillbirth, abortion) and whether there is incomplete reporting of such deaths.

METHODS

We searched PubMed, Embase, CINAHL, Web of Science and LILACS for studies reporting Zika-affected completed pregnancies (ending in foetal death or live birth), excluding studies whose aim required live birth. Studies 'allowed' foetal death if their populations were defined to encompass both live births and foetal deaths, regardless of whether deaths were actually found. Two authors independently extracted data and assessed study quality. Foetal death absolute and relative risks in Zika-affected vs. unaffected pregnancies were calculated.

RESULTS

We found 108 reports including 24 699 completed, Zika-affected pregnancies. The median absolute risk in 37 studies of completed, Zika-affected pregnancies was 6.3% (IQR 3.2%, 10.6%) for foetal death and 5.9% (IQR 0%, 29.1%) for non-fatal adverse outcomes (e.g. microcephaly). More studies allowed non-fatal adverse outcomes (95%) than foetal death (58%). Of studies which allowed them, 94% found at least one foetal death. In 37% of reports, it was unknown whether foetal deaths were allowed. Only one study had sufficient data to estimate a foetal death relative risk (11.05, 95% CI 3.43, 35.55).

CONCLUSIONS

Evidence was insufficient to determine whether foetal death risk is higher in Zika-affected pregnancies, but suggests quality of foetal death reporting should be improved, including stating whether foetal deaths were found, how many, and at what gestational ages, or justifying their exclusion.

Placental infection by Zika virus in French Guiana

OBJECTIVES

To describe placental findings on prenatal ultrasound and anatomopathological examination in women with Zika virus (ZIKV) infection, and to assess their association with congenital ZIKV infection and severe adverse outcome, defined as fetal loss or congenital Zika syndrome (CZS).

METHODS

This was a prospective study of pregnancies undergoing testing for maternal ZIKV infection at a center in French Guiana during the ZIKV epidemic. In ZIKV-positive women, congenital infection was defined as either a positive reverse transcription polymerase chain reaction result or identification of ZIKV-specific immunoglobulin-M in at least one placental, fetal or neonatal sample. Placental ZIKV-infection status was classified as non-exposed (placentae from non-infected women), exposed (placentae from ZIKV-infected women without congenital infection) or infected (placentae from ZIKV-infected women with proven congenital infection). Placentae were assessed by monthly prenatal ultrasound examinations, measuring placental thickness and umbilical artery Doppler parameters, and by anatomopathological examination after live birth or intrauterine death in women with ZIKV infection. The association of placental thickness during pregnancy and anatomopathological findings with the ZIKV status of the placenta was assessed. The association between placental findings and severe adverse outcome (CZS or fetal loss) in the infected group was also assessed.

RESULTS

Among 291 fetuses/neonates/placentae from women with proven ZIKV infection, congenital infection was confirmed in 76 cases, of which 16 resulted in CZS and 11 resulted in fetal loss. The 215 remaining placentae from ZIKV-positive women without evidence of congenital ZIKV infection represented the exposed group. A total of 334 placentae from ZIKV-negative pregnant women represented the non-exposed control group. Placentomegaly (placental thickness > 40 mm) was observed more frequently in infected placentae (39.5%) than in exposed placentae (17.2%) or controls (7.2%), even when adjusting for gestational age at diagnosis and comorbidities (adjusted hazard ratio (aHR), 2.02 (95% CI, 1.22-3.36) and aHR, 3.23 (95% CI, 1.86-5.61), respectively), and appeared earlier in infected placentae. In the infected group, placentomegaly was observed more frequently in cases of CZS (62.5%) or fetal loss (45.5%) than in those with asymptomatic congenital infection (30.6%) (aHR, 5.43 (95% CI, 2.17-13.56) and aHR, 4.95 (95% CI, 1.65-14.83), respectively). Abnormal umbilical artery Doppler was observed more frequently in cases of congenital infection resulting in fetal loss than in those with asymptomatic congenital infection (30.0% vs 6.1%; adjusted relative risk (aRR), 4.83 (95% CI, 1.09-20.64)). Infected placentae also exhibited a higher risk for any pathological anomaly than did exposed placentae (62.8% vs 21.6%; aRR, 2.60 (95% CI, 1.40-4.83)).

CONCLUSIONS

Early placentomegaly may represent the first sign of congenital infection in ZIKV-infected women, and should prompt enhanced follow-up of these pregnancies. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Congenital Zika syndrome: association between the gestational trimester of maternal infection, severity of brain computed tomography findings and microcephaly at birth

This study analyzed possible associations between the trimester of maternal Zika virus infection (ZIKV) in pregnancy, severity of brain computed tomography (CT) findings and the presence of microcephaly at birth in children with Congenital Zika Syndrome (CZS). It was an analytical study in a cohort of children with CZS. Symptoms of maternal infection were dichotomized into the 1^st trimester of pregnancy and other trimesters. Head circumference (HC) at birth was used to calculate the z-score. Mild microcephaly was defined as HC between 2 and ≥3 standard deviations (SD) below the mean for each gestational age and sex, and severe microcephaly when HC <3 SD below average. Brain CT images were evaluated by two radiologists and classified, according to the severity, into mild, moderate and severe. Fisher’s exact, Mann-Whitney and Kruskal-Wallis tests were used to verify the associations between variables. In 108 children, maternal infection in the 1^st trimester of pregnancy was associated with more severe brain CT abnormalities (p=0.038), greater severity of microcephaly at birth (p=0.013) and lower HC z-scores at birth (p=0.021). The severity of brain CT lesions was also associated with lower HC z-scores at birth (p<0.001). Maternal ZIKV infection during the first trimester of pregnancy proved to be an important risk factor for a more severe spectrum of CZS, as it is associated with more severe brain CT abnormalities and, consequently, with lower HC z-scores at birth.

Another piece of the Zika puzzle: assessing the associated factors to microcephaly in a systematic review and meta-analysis

BACKGROUND

Although it is known that Zika virus (ZIKV) infection during pregnancy may lead to microcephaly in the fetus, the prognostic factors associated with this tragic disorder remain unclear. We conducted a systematic review and meta-analysis to assess the prognostic factors associated with the incidence of microcephaly in congenital ZIKV infection.

METHODS

We conducted a comprehensive search in Ovid MEDLINE, Ovid MEDLINE (R) Epub ahead of print, Embase, Embase Classic, Web of Science, CINAHL, Cochrane CENTRAL, LILACS, and various thesis databases to identify human studies reporting microcephaly associated with congenital ZIKV infection. We requested primary data from the authors of the included studies to calculate summary estimates and conduct the meta-analysis of the most prevalent factors.

RESULTS

We screened 4106 titles and abstracts, and identified 12 studies for inclusion in the systematic review. The assessment of ZIKV infection and the definition of microcephaly varied among studies. A total of 6154 newborns/fetuses were enrolled; of those, 1120 (18.20%) had a diagnostic of ZIKV infection, of which 509 (45.45%) were diagnosed with microcephaly. Nine studies addressed the link between congenital ZIKV infection and neurological findings in newborns/fetuses. Half of the studies provided primary data. Three out of 11 factors of interest seem to be prognostic factors of microcephaly: infant's sex - males compared to females: Relative Risk (RR) 1.30, 95% Confidence Interval (95% CI) 1.14 to 1.49; the stage of pregnancy when infection occurred - infection in the first trimester of pregnancy compared to infection at other stages of pregnancy: RR 1.41, 95% CI 1.09 to 1.82; and asymptomatic infection compared to symptomatic infection during pregnancy: RR 0.68; 95% CI 0.60 to 0.77.

CONCLUSION

Our findings support the female-biased resistance hypothesis and reinforce the risk associated with the stage of pregnancy when ZIKV infection occurs. Continued surveillance of ZIKV infection during pregnancy is needed to identify additional factors that could contribute to developing microcephaly in affected fetuses.

PROTOCOL REGISTRATION

This systematic review was registered with the International Prospective Register of Systematic Reviews (PROSPERO), registration no. CRD 42018088075.

Pluripotent Stem Cell-Based Models: A Peephole into Virus Infections during Early Pregnancy

The rubella virus (RV) was the first virus shown to be teratogenic in humans. The wealth of data on the clinical symptoms associated with congenital rubella syndrome is in stark contrast to an incomplete understanding of the forces leading to the teratogenic alterations in humans. This applies not only to RV, but also to congenital viral infections in general and includes (1) the mode of vertical transmission, even at early gestation, (2) the possible involvement of inflammation as a consequence of an activated innate immune response, and (3) the underlying molecular and cellular alterations. With the progress made in the development of pluripotent stem cell-based models including organoids and embryoids, it is now possible to assess congenital virus infections on a mechanistic level. Moreover, antiviral treatment options can be validated, and newly emerging viruses with a potential impact on human embryonal development, such as that recently reflected by the Zika virus (ZIKV), can be characterized. Here, we discuss human cytomegalovirus (HCMV) and ZIKV in comparison to RV as viruses with well-known congenital pathologies and highlight their analysis on current models for the early phase of human development. This includes the implications of their genetic variability and, as such, virus strain-specific properties for their use as archetype models for congenital virus infections. In this review, we will discuss the use of induced pluripotent stem cells (iPSC) and derived organoid systems for the study of congenital virus infections with a focus on their prominent aetiologies, HCMV, ZIKV, and RV. Their assessment on these models will provide valuable information on how human development is impaired by virus infections; it will also add new insights into the normal progression of human development through the analysis of developmental pathways in the context of virus-induced alterations. These are exciting perspectives for both developmental biology and congenital virology.

Researching Zika in pregnancy: lessons for global preparedness

Our understanding of congenital infections is based on prospective studies of women infected during pregnancy. The EU has funded three consortia to study Zika virus, each including a prospective study of pregnant women. Another multi-centre study has been funded by the US National Institutes of Health. This Personal View describes the study designs required to research Zika virus, and questions whether funding academics in the EU and USA to work with collaborators in outbreak areas is an effective strategy. 3 years after the 2015-16 Zika virus outbreaks, these collaborations have taught us little about vertical transmission of the virus. In the time taken to approve funding, agree contracts, secure ethics approval, and equip laboratories, Zika virus had largely disappeared. By contrast, prospective studies based on local surveillance and standard-of-care protocols have already provided valuable data. Threats to fetal and child health pose new challenges for global preparedness requiring support for the design and implementation of locally appropriate protocols. These protocols can answer the key questions earlier than externally designed studies and at lower cost. Local protocols can also provide a framework for recruitment of unexposed controls that are required to study less specific outcomes. Other priorities include accelerated development of non-invasive tests, and longer-term storage of neonatal and antenatal samples to facilitate retrospective reconstruction of cohort studies.

Zika virus infection: A correlation between prenatal ultrasonographic and postmortem neuropathologic changes

This study presents a correlation between prenatal ultrasonographic images and neuropathologic findings of postmortem tissue samples from five confirmed cases of perinatal Zika virus (ZIKV) infection belonging to the cohort of the ZEN Initiative in Bucaramanga, Colombia. Deaths occurred between June 2016 and March 2017. Mothers consulted with ZIKV infection clinical manifestations or fetal central nervous system (CNS) abnormalities or both. A detailed ultrasound scan and neurosonographic protocol was performed by maternal fetal specialists. Perinatal autopsies were performed following the Colombian National Health Institute's ZIKV protocol. The autopsies were from two fetal deaths, and three early neonatal deaths. Gestational age was between 26^2/7 and 38^2/7 weeks. Two cases were classified as mild microcephaly. Few findings by ultrasound and pathology were found in case 1 because it was a late infection; the other cases presented findings corresponding to congenital Zika syndrome: craniofacial malformations, cerebellar hypoplasia, anomalies of the corpus callosum and ventriculomegaly, all confirmed in autopsy specimens. By ultrasonography, hyperechogenicities were seen in several brain structures, which correspond to cortical and periventricular calcifications, subependymal glial reactivity and perivascular rings. The ultrasound and pathological findings show a wide spectrum of CNS anomalies that confirm the neurotropic effect of the ZIKV, recognizing the neuroimaging findings of this disease (unilateral ventriculomegaly, alterations in the corpus callosum and cerebellum, and calcifications) are highly suggestive of ZIKV infection.

Zika virus infection as a cause of congenital brain abnormalities and Guillain-Barré syndrome: A living systematic review

Background: The Zika virus (ZIKV) caused a large outbreak in the Americas leading to the declaration of a Public Health Emergency of International Concern in February 2016. A causal relation between infection and adverse congenital outcomes such as microcephaly was declared by the World Health Organization (WHO) informed by a systematic review structured according to a framework of ten dimensions of causality, based on the work of Bradford Hill. Subsequently, the evidence has continued to accumulate, which we incorporate in regular updates of the original work, rendering it a living systematic review.

Methods: We present an update of our living systematic review on the causal relation between ZIKV infection and adverse congenital outcomes and between ZIKV and GBS for four dimensions of causality: strength of association, dose-response, specificity, and consistency. We assess the evidence published between January 18, 2017 and July 1, 2019.

Results: We found that the strength of association between ZIKV infection and adverse outcomes from case-control studies differs according to whether exposure to ZIKV is assessed in the mother (OR 3.8, 95% CI: 1.7-8.7, I ²=19.8%) or the foetus/infant (OR 37.4, 95% CI: 11.0-127.1, I ²=0%). In cohort studies, the risk of congenital abnormalities was 3.5 times higher after ZIKV infection (95% CI: 0.9-13.5, I ²=0%). The strength of association between ZIKV infection and GBS was higher in studies that enrolled controls from hospital (OR: 55.8, 95% CI: 17.2-181.7, I ²=0%) than in studies that enrolled controls at random from the same community or household (OR: 2.0, 95% CI: 0.8-5.4, I ²=74.6%). In case-control studies, selection of controls from hospitals could have biased results.

Conclusions: The conclusions that ZIKV infection causes adverse congenital outcomes and GBS are reinforced with the evidence published between January 18, 2017 and July 1, 2019.

Gottesfeld-Hohler Memorial Foundation Zika Virus Think Tank Summary

At a think tank bringing together experts on fetal neuroimaging, obstetric infectious diseases, and public health, we discussed trends in all of these areas for Zika virus. There is a wide variety of imaging findings in affected fetuses, influenced by timing of infection and probably host factors. The resources for diagnosis and interventions also vary by location with the hardest hit areas often having the fewest resources. We identified potential areas for both research and clinical collaboration as the Zika virus epidemic continues to evolve.

Infections in pregnancy

Infections in pregnancy represent a challenging and often underappreciated area of concern for many specialists and general practitioners and can cause serious sequelae. Antenatal status should be highlighted on pathology request forms, as this serves to alert the laboratory of the need to store serum for an extended period. Prior antenatal specimens can be forwarded to other laboratories to enable testing in parallel with the more recent sample. Women with a confirmed, potentially vertically transmissible infection should be referred to a specialist with expertise in the management of perinatal infections. Cytomegalovirus infection is the most common congenital infection. Women who care for young children are at greater risk of exposure to the virus. Preventive steps including hand hygiene and avoiding contact with children's urine, mucous and saliva are recommended for all pregnant women. The incidence of parvovirus B19 infection in pregnancy is unknown. This infection is highly contagious and may result in fetal loss; particularly in the first half of pregnancy, pregnant women should avoid contact with adults or children who may have an infection.

Update on the Animal Models and Underlying Mechanisms for ZIKV-Induced Microcephaly

The circulation of Zika virus (ZIKV) in nearly 80 countries and territories poses a significant global threat to public health. ZIKV is causally linked to severe developmental defects in the brain, recognized as congenital Zika syndrome (CZS), which includes microcephaly and other serious congenital neurological complications. Since the World Health Organization declared the ZIKV outbreak a public health emergency of international concern, remarkable progress has been made in the generation of different ZIKV infection animal models to gain insight into cellular targets and pathogenesis and to explore the associated underlying mechanisms. Here we focus on summarizing our current understanding of the effects of ZIKV on mammalian brain development in different developmental stages and discuss the potential underlying mechanisms of ZIKV-induced CZS, as well as future perspectives.

Maternal infection with Zika virus and prevalence of congenital disorders in infants: systematic review and meta-analysis

OBJECTIVE

Zika virus (ZIKV) infection is a vector-borne disease that can be transmitted sexually and vertically. The vertical transmission of the virus may lead to congenital Zika syndrome in infants. The aim of this study is to conduct a systematic review and meta-analysis of published reports documenting the prevalence of congenital Zika-related disorders in infants of mothers infected with ZIKV during pregnancy.

METHODS

We conducted a comprehensive search in Ovid MEDLINE, Ovid MEDLINE (R) Epub ahead of print, Embase, Embase Classic and Web of Science databases to identify human studies reporting prevalence of congenital disorders in infants of ZIKV-infected mothers.

RESULTS

We identified 25 reports selected for inclusion in the current study (n = 4683 subjects). The majority of the studies were from South American high-risk countries. Only one third of the identified studies were conducted in the United States. Clinical maternal symptoms included maculopapular rash (76.9%), arthralgia (46.4%), fever (45.5%) and headache (31.8%) with myalgia and conjunctivitis only presented in 25% of the cases. The most prevalent congenital disorder in the newborns was brain calcifications (42.6; 95% CI, 30.8-54.4), followed by ventriculomegaly (21.8; 95% CI, 15.2-28.4), joint abnormalities (13.2; 95% CI, 9.4-18.2), ocular abnormalities (4.2; 95% CI, 1.0-7.5) and microcephaly (3.9; 95% CI, 2.4-5.4).

CONCLUSION

The current study highlights the high prevalence of a range of congenital disorders in newborns of mothers infected with ZIKV. It warrants developing studies to further clarify the mechanisms by which each of these disorders occurs in response to the viral infection during pregnancy and its vertical transmission to the infants.

Assessing the utility of antivirals for preventing maternal-fetal transmission of zika virus in pregnant mice

Zika virus (ZIKV) infection during pregnancy has been associated with adverse outcomes and birth defects such as microcephaly in newborn children. Congenital malformations associated with ZIKV are believed to occur via direct infection of the fetus. Unfortunately, there are no licensed therapeutic or preventative tools to block maternal-fetal transmission of ZIKV. In this study, we developed a mouse model of ZIKV infection that specifically establishes vertical maternal-fetal transmission of ZIKV in 40-60% of fetuses when the dams acquire ZIKV infection during pregnancy. This mouse model somewhat mirrors the experience in humans at the peak of the epidemic in the Americas. Using this model, we demonstrate that a well-documented directly acting antiviral (DAA) compound that targets flaviviral RNA synthesis can completely prevent fetal infection when the treatment is started at the time of infection. Notably, we show that the treatment commenced at the time of peak viremia is still able to reduce the risk of fetal infection concomitant with significant reduction in placental viral load. Our results show for the first time the potential for clinical development of antiviral drugs for preventing vertical maternal-fetal transmission of ZIKV.

Factors associated with the development of Congenital Zika Syndrome: a case-control study

BACKGROUND

We aim to investigate possible maternal- and pregnancy-related factors associated with the development of Congenital Zika Syndrome (CZS) in children of mothers with probable gestational infection.

METHODS

This case-control study, we recruited mother-infant pairs between May 2015 and October 2017 in a pediatric infectious disease clinic in Rio de Janeiro. Inclusion criteria required either that the mother reported Zika infection symptoms during pregnancy or that the infant presented with clinical or imaging features of the CZS. Exclusion criteria included detection of an alternative cause for the patient's presentation or negative polymerase chain reaction assays for Zika in all specimens tested within 12 days from the beginning of maternal symptoms. Infants with CZS (CDC definition) were selected as cases and infants without CZS, but with probable maternal Zika virus infection during pregnancy, were selected as controls. Maternal and pregnancy-related informations were collected and their relationship to the presence of congenital anomalies due to CZS was assessed by Fisher exact or Mann-Whitney test.

RESULTS

Out of the 42 included neonates, 24 (57.1%) were diagnosed with CZS (cases). The mean maternal age at the birth was 21 years old. The early occurrence of maternal symptoms during pregnancy was the only variable associated with CZS (odds ratio = 0.87, 95% CI: 0.78-0.97). Case's mothers presented symptoms until the 25th week of gestational age (GA), while control's mothers presented until 36th weeks of GA. Income; illicit drug, alcohol, or tobacco use during pregnancy; other infections during pregnancy (including previous dengue infection) were not associated with CZS.

CONCLUSIONS

Our study corroborates the hypothesis that Zika virus infection earlier in pregnancy is a risk factor to the occurrence of congenital anomalies in their fetuses.

Efficiencies and kinetics of infection in different cell types/lines by African and Asian strains of Zika virus

After recent outbreaks, Zika virus (ZIKV) was linked to severe neurological diseases including Guillain-Barré syndrome in adults and microcephaly in newborns. The severities of pathological manifestations have been associated with different ZIKV strains. To better understand the tropism of ZIKV, we infected 10 human and four nonhuman cell lines (types) with two African (IbH30656 and MR766) and two Asian (PRVABC59 and H/FP/2013) ZIKV strains. Cell susceptibility to ZIKV infection was determined by examining viral titers, synthesis of viral proteins, and replication of positive and negative strands of viral genome. Among nonhuman cell lines, only Vero cells were efficiently infected by ZIKV. Among human cell lines, all were permissive to ZIKV infection. However, 293T and HeLa cells showed differential susceptibility towards African strains. In 293T cells, the NS1 protein was expressed at the high level by African strains but was almost not expressed by Asian strains though there was no obvious difference in viral genome replication, suggesting that the differential susceptibility might be controlled at the stage of viral protein translation. This study provides comprehensive results of the permissiveness of different cell types to both African and Asian ZIKV strains, which might help clarify their different pathogenesis.

Host target-based approaches against arboviral diseases

In the 20th century, socioeconomic and environmental changes facilitated the reintroduction of mosquitoes in developing cities, resulting in the reinsertion of mosquito-borne viral diseases and the dispersal of their causative agents on a worldwide scale. Recurrent outbreaks of arboviral diseases are being reported, even in regions without a previous history of arboviral disease transmission. Of note, arboviral infections represented approximately 30% of all emerging vector-borne diseases in the last decade. Therapeutic strategies against infectious viral diseases include the use of different classes of molecules that act directly on the pathogen and/or act by optimizing the host immune response. Drugs targeting the virus usually provide amelioration of symptoms by suppressing and controlling the infection. However, it is limited by the short-window of effectiveness, ineffectiveness against latent viruses, development of drug-resistant mutants and toxic side effects. Disease may also be a consequence of an excessive, uncontrolled or misplaced inflammatory response, treatments that interfere in host immune response are interesting options and can be used isolated or in combination with virus-targeted therapies. The use of host-targeted therapies requires specific knowledge regarding host immune patterns that may trigger dengue virus (DENV), chikungunya virus (CHIKV) or Zika virus (ZIKV) disease.