The proportion of asymptomatic infections and spectrum of disease among pregnant women infected by Zika virus: systematic monitoring in French Guiana, 2016

Characteristics, risk factors, and outcomes related to Zika virus infection during pregnancy in Northeastern Thailand: A prospective pregnancy cohort study, 2018-2020

BACKGROUND

In response to the 2015-2016 Zika virus (ZIKV) outbreak and the causal relationship established between maternal ZIKV infection and adverse infant outcomes, we conducted a cohort study to estimate the incidence of ZIKV infection in pregnancy and assess its impacts in women and infants.

METHODOLOGY/PRINCIPAL FINDINGS

From May 2018-January 2020, we prospectively followed pregnant women recruited from 134 participating hospitals in two non-adjacent provinces in northeastern Thailand. We collected demographic, clinical, and epidemiologic data and blood and urine at routine antenatal care visits until delivery. ZIKV infections were confirmed by real-time reverse transcriptase polymerase chain reaction (rRT-PCR). Specimens with confirmed ZIKV underwent whole genome sequencing. Among 3,312 women enrolled, 12 (0.36%) had ZIKV infections, of which two (17%) were detected at enrollment. Ten (83%, 3 in 2nd and 7 in 3rd trimester) ZIKV infections were detected during study follow-up, resulting in an infection rate of 0.15 per 1,000 person-weeks (95% CI: 0.07-0.28). The majority (11/12, 91.7%) of infections occurred in one province. Persistent ZIKV viremia (42 days) was found in only one woman. Six women with confirmed ZIKV infections were asymptomatic until delivery. Sequencing of 8 ZIKV isolates revealed all were of Asian lineage. All 12 ZIKV infected women gave birth to live, full-term infants; the only observed adverse birth outcome was low birth weight in one (8%) infant. Pregnancies in 3,300 ZIKV-rRT-PCR-negative women were complicated by 101 (3%) fetal deaths, of which 67 (66%) had miscarriages and 34 (34%) had stillbirths. There were no differences between adverse fetal or birth outcomes of live infants born to ZIKV-rRT-PCR-positive mothers compared to live infants born to ZIKV-rRT-PCR-negative mothers.

CONCLUSIONS/SIGNIFICANCE

Confirmed ZIKV infections occurred infrequently in this large pregnancy cohort and observed adverse maternal and birth outcomes did not differ between mothers with and without confirmed infections.

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.

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.

High seroprevalence of antibodies against arboviruses in postpartum women in Salvador, Brazil

Objectives

Arboviruses represent a major challenge to public health in Brazil. Dengue (DENV) virus has been endemic for decades, and the introduction of Zika (2015) and Chikungunya (2014) viruses (CHIKV) has imposed a significant burden on the country. The present study aimed to investigate the seroprevalence of Zika virus (ZIKV), DENV and CHIKV in women in Salvador, Bahia-Brazil.

Methods

Cross-sectional study involving postpartum women admitted to a maternity hospital in Salvador, Brazil. Anti-ZIKV, anti-DENV and anti-CHIKV immunoglobulin G was measured by enzyme-linked immunosorbent assay.

Results

A total of 302 women were enrolled with a median age: 26 years, interquartile range (21-33). Most self-declared as mixed-race or black skin color (92.4%). The seroprevalence was 57% for ZIKV); 91.4% for DENV, and 7.6% for CHIKV. Most participants denied awareness of previous arboviral infection, although 67 (22.3%) reported a previous history of ZIKV infection, 34 (11.1%) DENV infection and 9 (3%) CHIKV infection.

Conclusion

Our data indicate a high prevalence of past ZIKV and DENV infections in the population studied. Most of the participants remain susceptible to future CHIKV infection, highlighting the need for preventive and educational interventions. Our results suggest the need for continuous epidemiological surveillance of arboviral diseases, particularly among women residing in at-risk regions.

Emerging infectious diseases of the skin: a review of clinical and histologic findings

Emerging infectious diseases are of great importance to public health and clinical practice. This review aims to characterize the clinical and histopathologic features of emerging infectious diseases with cutaneous manifestations in order to increase awareness of these entities among dermatologists, pathologists, and dermatopathologists.

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.

Arthropod-Borne Flaviviruses in Pregnancy

Flaviviruses are a diverse group of enveloped RNA viruses that cause significant clinical manifestations in the pregnancy and postpartum periods. This review highlights the epidemiology, pathophysiology, clinical features, diagnosis, and prevention of the key arthropod-borne flaviviruses of concern in pregnancy and the neonatal period-Zika, Dengue, Japanese encephalitis, West Nile, and Yellow fever viruses. Increased disease severity during pregnancy, risk of congenital malformations, and manifestations of postnatal infection vary widely amongst this virus family and may be quite marked. Laboratory confirmation of infection is complex, especially due to the reliance on serology for which flavivirus cross-reactivity challenges diagnostic specificity. As such, a thorough clinical history including relevant geographic exposures and prior vaccinations is paramount for accurate diagnosis. Novel vaccines are eagerly anticipated to ameliorate the impact of these flaviviruses, particularly neuroinvasive disease manifestations and congenital infection, with consideration of vaccine safety in pregnant women and children pivotal. Moving forward, the geographical spread of flaviviruses, as for other zoonoses, will be heavily influenced by climate change due to the potential expansion of vector and reservoir host habitats. Ongoing 'One Health' engagement across the human-animal-environment interface is critical to detect and responding to emergent flavivirus epidemics.

Consequences of In Utero Zika Virus Exposure and Adverse Pregnancy and Early Childhood Outcomes: A Prospective Cohort Study

We aimed to describe adverse pregnancy outcomes among women who had symptomatic, RT-PCR-confirmed ZIKV infection and early childhood outcomes among their infants. We enrolled pregnant women with symptomatic, RT-PCR-confirmed ZIKV infection in a prospective cohort study, and their infants in a prospective pediatric cohort study. We defined adverse pregnancy and early childhood outcomes based on selected neurologic, ophthalmologic, auditory, musculoskeletal, and anthropometric abnormalities. We used RT-PCR and serologic tests to determine the ZIKV infection status of the child. Between 10 March and 24 November 2016, we enrolled 546 pregnant women with RT-PCR-confirmed ZIKV infection. The overall risk of adverse pregnancy and early childhood outcomes possibly related to in utero ZIKV exposure was 15.7% (95% CI: 12.8-19.0), distributed as follows: 3.6% (95% CI: 2.3-5.6) severe sequelae or fatality; 2.7% (95% CI: 1.6-4.5) major abnormalities; 9.4% (95% CI:7.1-12.2) mild abnormalities. The risk of severe sequelae or fatality was higher when ZIKV infection occurred during the first trimester (7.0%), compared to the second (2.7%) or third trimester (1.4%) (p = 0.02). Among the infants for whom ZIKV infection status could be determined, the vertical transmission rate was 3.0% (5/167) (95% CI: 1.1-7.2). Among pregnant women with symptomatic, RT-PCR-confirmed ZIKV infection, severe or major pregnancy or early childhood outcomes were present in 6.3% of fetuses and infants. Severe outcomes occurred more frequently in fetuses and infants whose mothers had been infected in the first trimester.

Scoping Review on the Impact of Outbreaks on Sexual and Reproductive Health Services: Proposed Frameworks for Pre-, Intra-, and Postoutbreak Situations

Introduction

Recent experiences from global outbreaks have highlighted the severe disruptions in sexual and reproductive health services that expose women and girls to preventable health risks. Yet, to date, there is no review studying the possible impact of outbreaks on sexual and reproductive health (SRH). Methodology. Studies reporting outbreaks impacting sexual and reproductive health and pregnancy outcomes were identified using MEDLINE, Embase, and ISI-WoS. Reported impacts were reviewed at systems, community, and legislative levels.

Results

The initial run listed 4423 studies; the 37 studies that met all inclusion criteria were mainly from Latin America and Africa. Studies on outbreaks of diseases like Zika and Ebola have documented declines in facility-based deliveries, contraceptive use, and antenatal and institutional care due to burdened healthcare system. Service usage was also impacted by a lack of trust in the healthcare system and system shocks, including workforce capacity and availability. At the community level, poverty and lack of awareness were critical contributors to poor access to SRH services. Assessing the target population's knowledge, attitude, beliefs, and behavior and using health literacy principles for communication were fundamental for designing service delivery. Online resources for SRH services were an acceptable medium of information among young adults. In outbreak situations, SRH and pregnancy outcomes were improved by implementing laboratory surveillance, free-of-cost contraceptive services, improved screening through professional training, and quality of care. In addition, mobile health clinics were reported to be effective in remote areas. Knowledge Contribution. In outbreaks, the interventions are categorized into preoutbreak, during, and postoutbreak periods. The proposed steps can help to improve and do course correction in emergencies. Though conducted before the COVID-19 crisis, the authors believe that lessons can be drawn from the paper to understand and mitigate the impact of the pandemic on sexual and reproductive health services.

Spatial Distribution and Burden of Emerging Arboviruses in French Guiana

Despite the health, social and economic impact of arboviruses in French Guiana, very little is known about the extent to which infection burden is shared between individuals. We conducted a large multiplexed serological survey among 2697 individuals from June to October 2017. All serum samples were tested for IgG antibodies against DENV, CHIKV, ZIKV and MAYV using a recombinant antigen-based microsphere immunoassay with a subset further evaluated through anti-ZIKV microneutralization tests. The overall DENV seroprevalence was estimated at 73.1% (70.6–75.4) in the whole territory with estimations by serotype at 68.9% for DENV-1, 38.8% for DENV-2, 42.3% for DENV-3, and 56.1% for DENV-4. The overall seroprevalence of CHIKV, ZIKV and MAYV antibodies was 20.3% (17.7–23.1), 23.3% (20.9–25.9) and 3.3% (2.7–4.1), respectively. We provide a consistent overview of the burden of emerging arboviruses in French Guiana, with useful findings for risk mapping, future prevention and control programs. The majority of the population remains susceptible to CHIKV and ZIKV, which could potentially facilitate the risk of further re-emergences. Our results underscore the need to strengthen MAYV surveillance in order to rapidly detect any substantial changes in MAYV circulation patterns.

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.

High Incidence of Zika or Chikungunya Infection among Pregnant Women Hospitalized Due to Obstetrical Complications in Northeastern Brazil-Implications for Laboratory Screening in Arbovirus Endemic Area

The diagnostic of arbovirus-related obstetric complications in high-risk pregnancy and childbirth care is challenging, especially in endemic areas. We conducted a prospective study to track active or recent Zika (ZIKV), dengue (DENV), or chikungunya (CHIKV) virus infection among hospitalized pregnant women (PW) with obstetric complications in a hospital at the epicenter of Zika outbreak and ZIKV-related microcephaly in Brazil. Clinical data and blood samples were collected at enrollment and 10 days after the admission of study participants, between October 2018 and May 2019. Further clinical data were extracted from medical records. Samples were screened by molecular and serological tests. Out of 780 participants, 93.1% (95% CI: 91.1–94.7%) presented previous DENV exposure (IgG). ZIKV, CHIKV, and/or DENV laboratory markers of recent or active infection were detected in 130 PW, yielding a prevalence of 16.6% (95% CI: 14.2–19.5%); 9.4% (95% CI: 7.4–11.7%), 7.4% (95% CI: 5.7–9.7%), and 0.38% (95% CI: 0.1–1.2%) of CHIKV, ZIKV, and DENV infections, respectively. Most ZIKV infections were detected by molecular assays (89.6%), while CHIKV infections were detected by serology (95.9%). Our findings highlight the need for arbovirus infections screening in PW with obstetrical complications, potentially associated to these infections in endemic areas regardless of the signs or symptoms suggestive of arboviral disease.

The Neurobiology of Zika Virus: New Models, New Challenges

The Zika virus (ZIKV) attracted attention due to one striking characteristic: the ability to cross the placental barrier and infect the fetus, possibly causing severe neurodevelopmental disruptions included in the Congenital Zika Syndrome (CZS). Few years after the epidemic, the CZS incidence has begun to decline. However, how ZIKV causes a diversity of outcomes is far from being understood. This is probably driven by a chain of complex events that relies on the interaction between ZIKV and environmental and physiological variables. In this review, we address open questions that might lead to an ill-defined diagnosis of CZS. This inaccuracy underestimates a large spectrum of apparent normocephalic cases that remain underdiagnosed, comprising several subtle brain abnormalities frequently masked by a normal head circumference. Therefore, new models using neuroimaging and artificial intelligence are needed to improve our understanding of the neurobiology of ZIKV and its true impact in neurodevelopment.

In utero Zika virus exposure and neurodevelopment at 24 months in toddlers normocephalic at birth: a cohort study

BACKGROUND

In utero exposure to Zika virus (ZIKV) is known to be associated with birth defects. The impact of in utero ZIKV exposure on neurodevelopmental outcomes in early childhood remains unclear. The objective of this study was to determine the impact of in utero ZIKV exposure on neurodevelopment at 24 months of age among toddlers who were born normocephalic to women who were pregnant during the 2016 ZIKV outbreak in French territories in the Americas.

METHODS

We conducted a population-based mother-child cohort study of women whose pregnancies overlapped with the 2016 ZIKV epidemic in Guadeloupe, Martinique, and French Guiana. Infants were included in this analysis if maternal ZIKV infection during pregnancy could be determined, the newborn had a gestational age ≥ 35 weeks, there were no abnormal transfontanelle cerebral ultrasound findings after delivery or no abnormal ultrasound findings on the last ultrasound performed during the third trimester of the mother's pregnancy, there was an absence of microcephaly at birth, and the parent completed the 24-month neurodevelopment assessment of the infant at 24 months (± 1 month) of age. ZIKV exposure of the toddler was determined by evidence of maternal ZIKV infection during pregnancy. Neurodevelopment assessments included the Ages and Stages Questionnaire (ASQ) for five dimensions of general development-communication, gross motor, fine motor, problem solving, and personal-social skills; the Modified Checklist for Autism on Toddlers (M-CHAT) for behavior; and the French MacArthur Inventory Scales (IFDC) for French language acquisition.

RESULTS

Between June 2018 and August 2019, 156 toddlers with and 79 toddlers without in utero ZIKV exposure completed neurodevelopment assessments. Twenty-four (15.4%) ZIKV-exposed toddlers and 20 (25.3%) ZIKV-unexposed toddlers had an ASQ result below the reference - 2SD cut-off (P = 0.10) for at least one of the five ASQ dimensions.

CONCLUSION

In one of the largest population-based cohorts of in utero ZIKV-exposed, normocephalic newborns to date, there were minimal differences apparent in neurodevelopment outcomes at 24 months of age compared to ZIKV-unexposed toddlers at 24 months of age.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02810210 . Registered 20 June 2016.

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.

Can Zika Virus Infection in High Risk Pregnant Women Be Differentiated on the Basis of Symptoms?

Zika virus (ZIKV) infection in pregnancy is associated with congenital neurological abnormalities. Our understanding of the full clinical spectrum of ZIKV infection is incomplete. Using data from this prospective cohort study consisting of 650 women attending a high-risk pregnancy clinic during the Zika virus outbreak in Brazil, we investigated the extent to which specific symptoms can be utilized to differentiate ZIKV-infected pregnant women from those with other pregnancy-related problems. All were tested for ZIKV in urine by RT-qPCR. Demographic and clinical data including physical symptoms during follow-up were recorded and analyzed with respect to Zika virus exposure status. Forty-eight (7.4%) women were positive for ZIKV by RT-qPCR. The majority (70.8%) were asymptomatic, and only four ZIKV-positive women (8.3%) reported symptoms during pregnancy that met the WHO case definition. Zika-positive and -negative women reported similar frequencies of ZIKV-like symptoms (as per the WHO definition): fever (16.7% vs. 13.6%), arthralgia/arthritis (10.4% vs. 11.3%), rash (4.2% vs. 5.3%), and conjunctivitis (2.1% vs. 3.2%). Most pregnant women positive for ZIKV in urine are asymptomatic and do not deliver a baby with microcephaly. Physical symptoms alone did not differentiate between high-risk pregnant women positive or negative for ZIKV.

Zika Virus and Arthritis/Arthralgia: A Systematic Review and Meta-Analysis

Dengue, chikungunya and Zika viruses share similar disease features, rendering them difficult to distinguish clinically. Incapacitating arthralgia/arthritis is a specific manifestation associated with chikungunya virus infection. However, the profile of arthralgia/arthritis in Zika virus (ZIKV) cases has not been well characterized. Articles were extracted from PubMed and Scopus databases reporting original data from patients with arthralgia/arthritis, according to the Cochrane Collaboration. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, 137 articles reporting ZIKV-associated joint symptoms were reviewed. Arthralgia was more frequently reported (n = 124 from case studies, n = 1779 from population-based studies) than arthritis (n = 7 and n = 121, respectively). Arthralgia was resolved in <1 week in 54%, and within 1–2 weeks in 40% of cases. The meta-analysis of cases in population-based studies identified a pooled prevalence of 53.55% for arthralgia. The pooled prevalence of arthralgia/arthritis during outbreaks depended on the geographic location, with a higher joint symptom burden observed in the Americas compared to South East Asia (Brazil: 60.79%; Puerto Rico: 68.89% and South East Asia: 26.46%). We conclude that non-specific constitutional arthralgia is the most common joint manifestation during ZIKV infection, being present in nearly half of cases but resolving by two weeks in >90% of these. We found no evidence of chronic rheumatic manifestations following ZIKV infection.

Estimation of mosquito-borne and sexual transmission of Zika virus in Australia: Risks to blood transfusion safety

BACKGROUND

Since 2015, Zika virus (ZIKV) outbreaks have occurred in the Americas and the Pacific involving mosquito-borne and sexual transmission. ZIKV has also emerged as a risk to global blood transfusion safety. Aedes aegypti, a mosquito well established in north and some parts of central and southern Queensland, Australia, transmits ZIKV. Aedes albopictus, another potential ZIKV vector, is a threat to mainland Australia. Since these conditions create the potential for local transmission in Australia and a possible uncertainty in the effectiveness of blood donor risk-mitigation programs, we investigated the possible impact of mosquito-borne and sexual transmission of ZIKV in Australia on local blood transfusion safety.

METHODOLOGY/PRINCIPAL FINDINGS

We estimated 'best-' and 'worst-' case scenarios of monthly reproduction number (R0) for both transmission pathways of ZIKV from 1996-2015 in 11 urban or regional population centres, by varying epidemiological and entomological estimates. We then estimated the attack rate and subsequent number of infectious people to quantify the ZIKV transfusion-transmission risk using the European Up-Front Risk Assessment Tool. For all scenarios and with both vector species R0 was lower than one for ZIKV transmission. However, a higher risk of a sustained outbreak was estimated for Cairns, Rockhampton, Thursday Island, and theoretically in Darwin during the warmest months of the year. The yearly estimation of the risk of transmitting ZIKV infection by blood transfusion remained low through the study period for all locations, with the highest potential risk estimated in Darwin.

CONCLUSIONS/SIGNIFICANCE

Given the increasing demand for plasma products in Australia, the current strategy of restricting donors returning from infectious disease outbreak regions to source plasma collection provides a simple and effective risk management approach. However, if local transmission was suspected in the main urban centres of Australia, potentially facilitated by the geographic range expansion of Ae. aegypti or Ae. albopictus, this mitigation strategy would need urgent review.

Age and geographic dependence of Zika virus infection during the outbreak on Yap island, 2007

Intensive surveillance of Zika virus infection conducted on Yap Island has provided crucial information on the epidemiological characteristics of the virus, but the rate of infection and medical attendance stratified by age and geographical location of the epidemic have yet to be fully clarified. In the present study, we reanalyzed surveillance data reported in a previous study. Likelihood-based Bayesian inference was used to gauge the age and geographically dependent force of infection and age-dependent reporting rate, with unobservable variables imputed by the data augmentation method. The inferred age-dependent component of the force of infection was suggested to be up to 3-4 times higher among older adults than among children. The age-dependent reporting rate ranged from 0.7% (5-9 years old) to 3.3% (50-54 years old). The proportion of serologically confirmed cases among total probable or confirmed cases was estimated to be 44.9%. The cumulative incidence of infection varied by municipality: Median values were over 80% in multiple locations (Gagil, Tomil, and Weloy), but relatively low values (below 50%) were derived in other locations. However, the possibility of a comparably high incidence of infection was not excluded even in municipalities with the lowest estimates. The results suggested a high degree of heterogeneity in the Yap epidemic. The force of infection and reporting rate were higher among older age groups, and this discrepancy implied that the demographic patterns were remarkably different between all infected and medically attended individuals. A higher reporting rate may have reflected more severe clinical presentation among adults. The symptomatic ratio in dengue cases is known to correlate with age, and our findings presumably indicate a similar tendency in Zika virus disease.

Immunological Memory to Zika Virus in a University Community in Colombia, South America

Zika virus appeared in South America in 2015, generating alarm worldwide as it causes microcephaly and autoimmunity. This study aims to determine the serological footprint of the incoming epidemic in a student community and to characterize the memory functional cell response during post convalescence. In a cross-sectional study, Zika-specific IgG using LIA immunoassay was found in 328 university students (CI=95%), while in the second phase, the functional cellular memory response for IFN-γ and IL-2 was quantified using post-stimulus ELISpot with inactivated virus, starting with individuals seropositive for Zika and control individuals (seropositive only for Dengue and seronegative for Zika-Dengue). Depending on the antigen used, memory humoral response (IgG) against Zika Virus was observed in >60% of the population; seropositivity for NS1 was 21.1% higher than E antigen with high intensity. The analysis of cell functionality in 22 individuals seropositive for Zika virus revealed either IFN-γ+ or IL-2+ cells in 86.3% of cases (Th1 profile), presenting multifunctionality in 50% (11 individuals), 64% of which presented> 6 SFC/104 PBMCs (>600 SFC/106 PBMC), reflecting memory circulating cells. A good agreement (Kappa= 0.754) was observed between the coexistence of both cellular and humoral responses but not in their intensity.

Impact of Zika Virus Emergence in French Guiana: A Large General Population Seroprevalence Survey

BACKGROUND

Since the identification of Zika virus (ZIKV) in Brazil in May 2015, the virus has spread throughout the Americas. However, ZIKV burden in the general population in affected countries remains unknown.

METHODS

We conducted a general population survey in the different communities of French Guiana through individual interviews and serologic survey during June-October 2017. All serum samples were tested for anti-ZIKV immunoglobulin G antibodies using a recombinant antigen-based SGERPAxMap microsphere immunoassay, and some of them were further evaluated through anti-ZIKV microneutralization tests.

RESULTS

The overall seroprevalence was estimated at 23.3% (95% confidence interval [CI], 20.9%-25.9%) among 2697 participants, varying from 0% to 45.6% according to municipalities. ZIKV circulated in a large majority of French Guiana but not in the most isolated forest areas. The proportion of reported symptomatic Zika infection was estimated at 25.5% (95% CI, 20.3%-31.4%) in individuals who tested positive for ZIKV.

CONCLUSIONS

This study described a large-scale representative ZIKV seroprevalence study in South America from the recent 2015-2016 Zika epidemic. Our findings reveal that the majority of the population remains susceptible to ZIKV, which could potentially allow future reintroductions of the virus.

Management of Travel-Related Infectious Diseases in the Emergency Department

Purpose of Review

Emergency physicians generally have limited exposure to internationally acquired illnesses. However, travelers can present quite ill, and delays in recognition and treatment can lead to increased morbidity and mortality. This paper aims to summarize typical presentations of common international diseases and provide the emergency physician with a practical approach based on current guidelines.

Recent Findings

In the treatment of traveler’s diarrhea, azithromycin has become the treatment of choice due to the growing antibiotic resistance. Intravenous artesunate was approved in 2019 under investigational new drug protocol for the treatment of severe malaria, and artemisinin-based combination therapies (ACTs) have become the first-line treatment for most cases of uncomplicated malaria. Since the 2015 outbreak, Zika has become a concern to many travelers, but the current treatment is supportive.

Summary

Clinicians should be aware of a few noteworthy updates in the treatment of internationally acquired illnesses, but more importantly, they must recognize warning signs of severe illness and treat promptly. Future research on workup and disposition could help emergency physicians identify which patients need admission in well-appearing febrile travelers.

ZIKA Virus infection in pregnant women in French Guiana: More precarious-more at risk

Background

A recent study in French Guiana suggested that populations living in precarious neighborhoods were more at risk for Chikungunya CHIKV than those living in more privileged areas. The objective of the present study was to test the hypothesis that Zika virus (ZIKV) infection was more frequent in precarious pregnant women than in non-precarious pregnant women, as reflected by their health insurance status.

Methods

A multicentric cross-sectional study was conducted in Cayenne hospital including ZIKV pregnant women with serological or molecular proof of ZIKV during their pregnancy between January and December 2016. Health insurance information was recorded at delivery, which allowed separating women in: undocumented foreigners, precarious but with residence permit, and non-precarious.

Results

A total of 6654 women were included. Among them 1509 (22,7%) had confirmed ZIKV infection. Most women were precarious (2275/3439) but the proportion of precarious women was significantly greater in ZIKV-confirmed 728/906 (80.4%) than the ZIKV-negatives 1747/2533 (69.0%), p<0.0001. There were 1142 women classified as non-precarious, 1671 were precarious legal residents, and 1435 were precarious and undocumented. Precariousness and undocumented status were associated with a higher prevalence of ZIKV during pregnancy (adjusted prevalence ratio = 1.59 (95%CI = 1.29–1.97), p<0.0001), (adjusted prevalence ratio = 1.5 (95%CI = 1.2–1.8), p<0.0001), respectively.

Conclusions

These results illustrate that in French Guiana ZIKV transmission disproportionately affected the socially vulnerable pregnant women, presumably because of poorer housing conditions, and lack of vector control measures in poor neighborhoods.

A recent study in French Guiana suggested that populations living in precarious neighborhoods were more at risk for chikungunya CHIKV than those living in more privileged areas. The objective of the present study was to test the hypothesis that Zika virus (ZIKV) infection was more frequent in precarious pregnant women than in non-precarious pregnant women as reflected by their health insurance status. A multicenter cross-sectional study was conducted including ZIKV pregnant women with serological or molecular proof of ZIKV during their pregnancy between January and December 2016. Health insurance information was recorded at delivery, which allowed separating women into: undocumented foreigners, precarious but with residence permit, and non-precarious. Overall 6654 women were included. Among them, 1509 (22,7%) had confirmed ZIKV infection. The majority of women were precarious, but the proportion of precarious women was significantly greater in ZIKV-confirmed 728/906 (80.4%) than the ZIKV-negatives 1747/2533 (69.0%). Precariousness and undocumented status were associated with a higher prevalence of ZIKV acquisition during pregnancy. The present results illustrate that in French Guiana, as elsewhere, ZIKV transmission disproportionately affected the socially vulnerable pregnant women, presumably because of poorer housing conditions, and lack of vector control measures in poor neighborhoods.

Genetic Diversity of Collaborative Cross Mice Controls Viral Replication, Clinical Severity, and Brain Pathology Induced by Zika Virus Infection, Independently of Oas1b

The explosive spread of Zika virus (ZIKV) has been associated with major variations in severe disease and congenital afflictions among infected populations, suggesting an influence of host genes. We investigated how genome-wide variants could impact susceptibility to ZIKV infection in mice. We first describe that the susceptibility of Ifnar1-knockout mice is largely influenced by their genetic background. We then show that Collaborative Cross (CC) mice, which exhibit a broad genetic diversity, in which the type I interferon receptor (IFNAR) was blocked by an anti-IFNAR antibody expressed phenotypes ranging from complete resistance to severe symptoms and death, with large variations in the peak and the rate of decrease in the plasma viral load, in the brain viral load, in brain histopathology, and in the viral replication rate in infected cells. The differences in susceptibility to ZIKV between CC strains correlated with the differences in susceptibility to dengue and West Nile viruses between the strains. We identified highly susceptible and resistant mouse strains as new models to investigate the mechanisms of human ZIKV disease and other flavivirus infections. Genetic analyses revealed that phenotypic variations are driven by multiple genes with small effects, reflecting the complexity of ZIKV disease susceptibility in the human population. Notably, our results rule out the possibility of a role of the Oas1b gene in the susceptibility to ZIKV. Altogether, the findings of this study emphasize the role of host genes in the pathogeny of ZIKV infection and lay the foundation for further genetic and mechanistic studies.IMPORTANCE In recent outbreaks, ZIKV has infected millions of people and induced rare but potentially severe complications, including Guillain-Barré syndrome and encephalitis in adults. While several viral sequence variants were proposed to enhance the pathogenicity of ZIKV, the influence of host genetic variants in mediating the clinical heterogeneity remains mostly unexplored. We addressed this question using a mouse panel which models the genetic diversity of the human population and a ZIKV strain from a recent clinical isolate. Through a combination of in vitro and in vivo approaches, we demonstrate that multiple host genetic variants determine viral replication in infected cells and the clinical severity, the kinetics of blood viral load, and brain pathology in mice. We describe new mouse models expressing high degrees of susceptibility or resistance to ZIKV and to other flaviviruses. These models will facilitate the identification and mechanistic characterization of host genes that influence ZIKV pathogenesis.

Zika Virus Infection in Pregnant Women, Yucatan, Mexico

Infection was associated with a high incidence of symptomatic disease but no congenital syndrome.

We report demographic, epidemiologic, and clinical findings for a prospective cohort of pregnant women during the initial phase of Zika virus introduction into Yucatan, Mexico. We monitored 115 pregnant women for signs of active or recent Zika virus infection. The estimated cumulative incidence of Zika virus infection was 0.31 and the ratio of symptomatic to asymptomatic cases was 1.7 (range 1.3–4.0 depending on age group). Exanthema was the most sensitive clinical sign but also the least specific. Conjunctival hyperemia, joint edema, and exanthema were the combination of signs that had the highest specificity but low sensitivity. We did not find evidence of vertical transmission or fetal anomalies, likely because of the low number of pregnant women tested. We also did not find evidence of congenital disease. Our findings emphasize the limited predictive value of clinical features in areas where Zika virus cocirculates with other flaviviruses.

Dengue, Zika and chikungunya during pregnancy: pre- and post-travel advice and clinical management

RATIONALE FOR REVIEW

Young adults of childbearing age and pregnant women are travelling more frequently to tropical areas, exposing them to specific arboviral infections such as dengue, zika and chikungunya viruses, which may impact ongoing and future pregnancies. In this narrative review, we analyse their potential consequences on pregnancy outcomes and discuss current travel recommendations.

MAIN FINDINGS

Dengue virus may be associated with severe maternal complications, particularly post-partum haemorrhage. Its association with adverse fetal outcomes remains unclear, but prematurity, growth retardation and stillbirths may occur, particularly in cases of severe maternal infection. Zika virus is a teratogenic infectious agent associated with severe brain lesions, with similar risks to other well-known TORCH pathogens. Implications of chikungunya virus in pregnancy are mostly related to intrapartum transmission that may be associated with severe neonatal infections and long-term morbidity.

TRAVEL RECOMMENDATIONS

Few agencies provide specific travel recommendations for travelling pregnant patients or couples trying to conceive and discrepancies exist, particularly regarding Zika virus prevention. The risks significantly depend on epidemiological factors that may be difficult to predict. Prevention relies principally on mosquito control measures. Couples trying to conceive and pregnant women should receive adequate information about the potential risks. It seems reasonable to advise pregnant women to avoid unnecessary travel to Aedes spp. endemic regions. The current rationale to avoid travel and delay conception is debatable in the absence of any epidemic. Post-travel laboratory testing should be reserved for symptomatic patients.

Route of Infection Influences Zika Virus Shedding in a Guinea Pig Model

Due to the recent epidemic of Zika virus (ZIKV) infection and resulting sequelae, as well as concerns about both the sexual and vertical transmission of the virus, renewed attention has been paid to the pathogenesis of this unique arbovirus. Numerous small animal models have been used in various ZIKV pathogenicity studies, however, they are often performed using immunodeficient or immunosuppressed animals, which may impact disease progression in a manner not relevant to immunocompetent humans. The use of immunocompetent animal models, such as macaques, is constrained by small sample sizes and the need for specialized equipment/staff. Here we report the establishment of ZIKV infection in an immunocompetent small animal model, the guinea pig, using both subcutaneous and vaginal routes of infection to mimic mosquito-borne and sexual transmission. Guinea pigs developed clinical signs consistent with mostly asymptomatic and mild disease observed in humans. We demonstrate that the route of infection does not significantly alter viral tissue tropism but does impact mucosal shedding mechanics. We also demonstrate persistent infection in sensory and autonomic ganglia, identifying a previously unrecognized niche of viral persistence that could contribute to viral shedding in secretions. We conclude that the guinea pig represents a useful and relevant model for ZIKV pathogenesis.

Low seroprevalence of Zika virus infection among adults in Southern Taiwan

Background

We recently conducted a serosurvey of newly arrived workers in Taiwan from four Southeast Asian countries which revealed that 1% of the migrant workers had laboratory-confirmed recent Zika virus (ZIKV) infection. Taiwan, where Aedes mosquitoes are prevalent, has a close relationship with Southeast Asian countries. Up to now, 21 imported cases of ZIKV infection have been reported in Taiwan, but there has been no confirmed indigenous case. The aim of this serosurvey was to assess whether there was unrecognized ZIKV infections in Taiwan.

Methods

A total of 212 serum samples collected in a cross-sectional seroepidemiologic study conducted during the end of the 2015 dengue epidemic in Tainan, Taiwan, were analyzed. Anti-ZIKV IgM and IgG were tested using commercial enzyme-linked immunosorbent assays (ELISAs). Plaque reduction neutralization tests (PRNTs) for ZIKV and four dengue virus (DENV) serotypes were performed for samples with positive anti-ZIKV antibodies. A confirmed case of ZIKV infection was defined by ZIKV PRNT₉₀ titer ratio ≥ 4 compared to four DENV serotypes.

Results

The mean age of the 212 participants was 54.0 years (standard deviation 13.7 years), and female was predominant (67.0%). Anti-ZIKV IgM and IgG were detected in 0 (0%) and 9 (4.2%) of the 212 participants, respectively. For the 9 samples with anti-ZIKV IgG, only 1 sample had 4 times higher ZIKV PRNT₉₀ titers compared to PRNT₉₀ titers against four dengue virus serotypes; this individual denied having traveled abroad.

Conclusions

The results suggest that undetected indigenous ZIKV transmission might have occurred in Taiwan. The findings also suggest that the threat of epidemic transmission of ZIKV in Taiwan does exist due to extremely low-level of herd immunity. Our study also indicates that serological tests for ZIKV-specific IgG remain a big challenge due to cross-reactivity, even in dengue non-endemic countries.

Vaccination coverage in the context of the emerging Yellow Fever threat in French Guiana

Background

French Guiana, a French overseas department located in South America between Brazil and Surinam, is the only European territory geographically located in the Amazonian forest complex and is considered endemic for yellow fever (YF).

In the context of the emergent threat of YF in Latin America, we conducted a large household cross-sectional survey from June to October 2017 to estimate vaccination coverage in the population and to determine associations with sociodemographic and geographical characteristics.

Methodology/Principal findings

In total, 1,415 households and 2,697 individuals were included from the 22 municipalities of French Guiana. YF vaccination coverage was estimated at 95.0% (95% CI: 93.4–96.2) in the entire territory but was spatially heterogeneous, with the lowest levels estimated in the western part of the territory along the Surinamese cross-border region, particularly in children under 16 years who were not enrolled in school, immigrant adults and disadvantaged populations with low socioeconomic indexes.

Conclusions/Significance

Despite the good vaccination coverage against YF in the general population of French Guiana resulting from the compulsory nature of YF vaccination for residents and travelers, there is an urgent need to improve vaccination coverage in vulnerable populations living in the northwestern part of the territory to limit the risk of transmission in the context of the emerging YF threat in South America.

Despite the relative rarity of YF and the significant number of infectious and tropical diseases in French Guiana, clinicians should adopt a high index of suspicion for YF, particularly in vulnerable and at-risk populations.

Yellow fever (YF) is the most severe arbovirus to circulate in the Americas. French Guiana, a French overseas department located in South America between Brazil and Surinam, is the only European territory geographically located in the Amazonian forest complex and is considered endemic for YF. We conducted a large general population survey from June to October 2017 to estimate vaccination coverage in the population and to identify target vulnerable populations for catch-up vaccination strategies. In total, 1,415 households and 2,697 individuals were included from the 22 municipalities of French Guiana. YF vaccination coverage was estimated at 95.0% (95% CI: 93.4–96.2) in the entire territory but was spatially heterogeneous, with the lowest levels estimated in the western part of the territory along the Surinamese cross-border region, particularly in children under 16 years who were not enrolled in school, immigrant adults and disadvantaged groups of populations with low socioeconomic indexes. Our findings showed that vaccination campaigns should be prioritized and adapted to improve vaccination coverage among vulnerable populations living in the northwestern part of the territory to limit the risk of transmission in the context of the emerging YF threat in South America. Despite the relative rarity of YF and the significant number of infectious and tropical diseases in French Guiana, clinicians should adopt a high index of suspicion for YF, particularly in vulnerable and at-risk populations.

Assessing Zika Virus Transmission Within Households During an Outbreak in Martinique, 2015-2016

Since 2015, Zika virus (ZIKV) has caused large epidemics in the Americas. Households are natural targets for control interventions, but quantification of the contribution of household transmission to overall spread is needed to guide policy. We developed a modeling framework to evaluate this contribution and key epidemic features of the ZIKV epidemic in Martinique in 2015-2016 from the joint analysis of a household transmission study (n = 68 households), a study among symptomatic pregnant women (n = 281), and seroprevalence surveys of blood donors (n = 457). We estimated that the probability of mosquito-mediated within-household transmission (from an infected member to a susceptible one) was 21% (95% credible interval (CrI): 5, 51), and the overall probability of infection from outside the household (i.e., in the community) was 39% (95% CrI: 27, 50). Overall, 50% (95% CrI: 43, 58) of the population was infected, with 22% (95% CrI: 5, 46) of infections acquired in households and 40% (95% CrI: 23, 56) being asymptomatic. The probability of presenting with Zika-like symptoms due to another cause was 16% (95% CrI: 10, 23). This study characterized the contribution of household transmission in ZIKV epidemics, demonstrating the benefits of integrating multiple data sets to gain more insight into epidemic dynamics.

The association between Zika virus infection and microcephaly in Brazil 2015-2017: An observational analysis of over 4 million births

BACKGROUND

In 2015, high rates of microcephaly were reported in Northeast Brazil following the first South American Zika virus (ZIKV) outbreak. Reported microcephaly rates in other Zika-affected areas were significantly lower, suggesting alternate causes or the involvement of arboviral cofactors in exacerbating microcephaly rates.

METHODS AND FINDINGS

We merged data from multiple national reporting databases in Brazil to estimate exposure to 9 known or hypothesized causes of microcephaly for every pregnancy nationwide since the beginning of the ZIKV outbreak; this generated between 3.6 and 5.4 million cases (depending on analysis) over the time period 1 January 2015-23 May 2017. The association between ZIKV and microcephaly was statistically tested against models with alternative causes or with effect modifiers. We found no evidence for alternative non-ZIKV causes of the 2015-2017 microcephaly outbreak, nor that concurrent exposure to arbovirus infection or vaccination modified risk. We estimate an absolute risk of microcephaly of 40.8 (95% CI 34.2-49.3) per 10,000 births and a relative risk of 16.8 (95% CI 3.2-369.1) given ZIKV infection in the first or second trimester of pregnancy; however, because ZIKV infection rates were highly variable, most pregnant women in Brazil during the ZIKV outbreak will have been subject to lower risk levels. Statistically significant associations of ZIKV with other birth defects were also detected, but at lower relative risks than that of microcephaly (relative risk < 1.5). Our analysis was limited by missing data prior to the establishment of nationwide ZIKV surveillance, and its findings may be affected by unmeasured confounding causes of microcephaly not available in routinely collected surveillance data.

CONCLUSIONS

This study strengthens the evidence that congenital ZIKV infection, particularly in the first 2 trimesters of pregnancy, is associated with microcephaly and less frequently with other birth defects. The finding of no alternative causes for geographic differences in microcephaly rate leads us to hypothesize that the Northeast region was disproportionately affected by this Zika outbreak, with 94% of an estimated 8.5 million total cases occurring in this region, suggesting a need for seroprevalence surveys to determine the underlying reason.

Maternal-fetal transmission and adverse perinatal outcomes in pregnant women infected with Zika virus: prospective cohort study in French Guiana

OBJECTIVES

To estimate the rates of maternal-fetal transmission of Zika virus, adverse fetal/neonatal outcomes, and subsequent rates of asymptomatic/symptomatic congenital Zika virus infections up to the first week of life.

DESIGN

Cohort study with prospective data collection and subsequent review of fetal/neonatal outcomes.

SETTINGS

Referral centre for prenatal diagnosis of the French Guiana Western Hospital.

PARTICIPANTS

Pregnant women at any stage of pregnancy with a laboratory confirmed symptomatic or asymptomatic Zika virus infection during the epidemic period in western French Guiana. The cohort enrolled 300 participants and prospectively followed their 305 fetuses/newborns.

MAIN OUTCOME MEASURES

Rate of maternal-fetal transmission of Zika virus (amniotic fluid, fetal and neonatal blood, urine, cerebrospinal fluid, and placentas); clinical, biological, and radiological outcomes (blindly reviewed); and adverse outcomes defined as moderate signs potentially related to congenital Zika syndrome (CZS), severe complications compatible with CZS, or fetal loss. Associations between a laboratory confirmed congenital Zika virus infection and adverse fetal/neonatal outcomes were evaluated.

RESULTS

Maternal-fetal transmission was documented in 26% (76/291) of fetuses/newborns with complete data. Among the Zika virus positive fetuses/newborns, 45% (34/76) presented with no signs/complications at birth, 20% (15/76) with moderate signs potentially related to CZS, 21% (16/76) with severe complications compatible with CZS, and 14% (11/76) with fetal loss. Compared with the Zika virus positive fetuses/neonates, those that were identified as negative for Zika virus (215/291) were less likely to present with severe complications (5%; 10/215) or fetal loss (0.5%; 1/215; relative risk 6.9, 95% confidence interval 3.6 to 13.3). Association between a positive Zika virus test and any adverse fetal/neonatal outcome was also significant (relative risk 4.4, 2.9 to 6.6). The population attributable fraction estimates that a confirmed congenital Zika virus infection contributes to 47% of adverse outcomes and 61% of severe adverse outcomes observed.

CONCLUSION

In cases of a known maternal Zika virus infection, approximately a quarter of fetuses will become congenitally infected, of which a third will have severe complications at birth or fetal loss. The burden of CZS might be lower than initially described in South America and may not differ from other congenital infections.

Current challenges and implications for dengue, chikungunya and Zika seroprevalence studies worldwide: A scoping review

BACKGROUND

Arboviral infections are a public health concern and an escalating problem worldwide. Estimating the burden of these diseases represents a major challenge that is complicated by the large number of unapparent infections, especially those of dengue fever. Serological surveys are thus required to identify the distribution of these diseases and measure their impact. Therefore, we undertook a scoping review of the literature to describe and summarize epidemiological practices, findings and insights related to seroprevalence studies of dengue, chikungunya and Zika virus, which have rapidly expanded across the globe in recent years.

METHODOLOGY/PRINCIPAL FINDINGS

Relevant studies were retrieved through a literature search of MEDLINE, WHOLIS, Lilacs, SciELO and Scopus (2000 to 2018). In total, 1389 publications were identified. Studies addressing the seroprevalence of dengue, chikungunya and/or Zika written in English or French and meeting the inclusion and exclusion criteria were included. In total, 147 studies were included, from which 185 data points were retrieved, as some studies used several different samples. Most of the studies were exclusively conducted on dengue (66.5%), but 16% were exclusively conducted on chikungunya, and 7 were exclusively conducted on Zika; the remainder were conducted on multiple arboviruses. A wide range of designs were applied, but most studies were conducted in the general population (39%) and in households (41%). Although several assays were used, enzyme-linked immunosorbent assays (ELISAs) were the predominant test used (77%). The temporal distribution of chikungunya studies followed the virus during its rapid expansion since 2004. The results revealed heterogeneity of arboviruses seroprevalence between continents and within a given country for dengue, chikungunya and Zika viruses, ranging from 0 to 100%, 76% and 73% respectively.

CONCLUSIONS/SIGNIFICANCE

Serological surveys provide the most direct measurement for defining the immunity landscape for infectious diseases, but the methodology remains difficult to implement. Overall, dengue, chikungunya and Zika serosurveys followed the expansion of these arboviruses, but there remain gaps in their geographic distribution. This review addresses the challenges for researchers regarding study design biases. Moreover, the development of reliable, rapid and affordable diagnosis tools represents a significant issue concerning the ability of seroprevalence surveys to differentiate infections when multiple viruses co-circulate.

Diagnosis and outcomes of pregnant women with Zika virus infection in two municipalities of Risaralda, Colombia: Second report of the ZIKERNCOL study

BACKGROUND

Zika virus (ZIKV) infection has emerged as a significant threat for pregnant women and newborns in populations living in or visiting Latin America. We previously reported a preliminary analysis in Sucre, Colombia, as the first group of pregnant women with RT-PCR-confirmed ZIKV (ZIKa enEmbarazadas yReciénNacidos enCOLombia, ZIKERNCOL).

METHODS

In this second report, findings of the first 86 pregnant women from La Virginia and Dosquebradas (municipalities), Risaralda, Colombia, with RT-PCR-confirmed ZIKV infection are reported. Clinical, demographical and obstetrical findings are described.

RESULTS

All women reported ZIKV symptoms during pregnancy: 79.1% rash, 55.8% fever, among others. In addition to ZIKV, RT-PCR was positive for dengue in 18.6%; 45.3% Dengue IgM+; 5.8% RT-PCR positive for chikungunya; 3.6% Chikungunya IgM+. STORCH screening in mother: 11.6% IgG + anti-Toxoplasma gondii, 6% IgG + anti-rubella, 4.7% IgG + CMV. The rest of STORCH tests were negative. Microcephaly was observed in 2.4% of the newborns. No calcifications or other CNS alterations were detected. One newborn had cleft palate and one had bilateral renal ectopy.

CONCLUSIONS

The rate of microcephaly in our cohort was consistent with other studies. Pregnant women in endemic areas should be followed and tested according to standard protocols, and asymptomatic ZIKV infection should be considered. Long-term follow-up of children is required in the congenital Zika syndrome (CZS) assessment.

Zika virus outbreak in Suriname, a report based on laboratory surveillance data

INTRODUCTION

Since the identification of ZIKV in Brazil in May 2015, the virus has spread extensively throughout the Americas. Cases of ZIKV infection have been reported in Suriname since October 2, 2015.

METHODS

A laboratory-based surveillance system was quickly implemented according to previous experience with the emergence of chikungunya. General practitioners and public health centers located in different districts of Suriname were asked to send blood samples from suspicious cases to Academic Hospital for molecular diagnosis of Zika virus infection. We investigated Zika-related laboratory data collected during surveillance and response activities to provide the first outbreak report in Suriname in terms of time, location and person.

RESULTS

A total of 791 molecularly confirmed cases were reported during a 48-week interval from October 2015 to August 2016. The majority of ZIKV-positive cases involved women between 20 and 39 years of age, reflecting concern about Zika infection during pregnancy. The outbreak peaked in mid-January and gradually spread from the district of Paramaribo to western coastal areas.

DISCUSSION

This report provides a simple and comprehensive description of the outbreak in Suriname and demonstrates the utility of laboratory data to highlight the spatiotemporal dynamics of the outbreak in that country.

Prevalence of asymptomatic Zika virus infection: a systematic review

Objective

To conduct a systematic review to estimate the prevalence of asymptomatic Zika virus infection in the general population and in specific population groups.

Methods

We searched PubMed®, Embase® and LILACS online databases from inception to 26 January 2018. We included observational epidemiological studies where laboratory testing was used to confirm positive exposure of participants to Zika virus and in which Zika virus symptom status was also recorded. We excluded studies in which having symptoms of Zika virus was a criterion for inclusion. The main outcome assessed was percentage of all Zika virus-positive participants who were asymptomatic. We used a quality-effects approach and the double arcsine transformation for the meta-analysis.

Findings

We assessed 753 studies for inclusion, of which 23 were included in the meta-analysis, totalling 11 305 Zika virus-positive participants. The high degree of heterogeneity in the studies (I² = 99%) suggests that the pooled prevalence of asymptomatic Zika virus-positive participants was probably not a robust estimate. Analysis based on subgroups of the population (general population, returned travellers, blood donors, adults with Guillain–Barré syndrome, pregnant women and babies with microcephaly) was not able to explain the heterogeneity. Funnel and Doi plots showed major asymmetry, suggesting selection bias or true heterogeneity.

Conclusion

Better-quality research is needed, using standardized methods, to determine the true prevalence of asymptomatic Zika virus and whether it varies between populations or over time.

Prevalence of Guillain-Barré syndrome among Zika virus infected cases: a systematic review and meta-analysis

Zika virus (ZIKV) is an emergent flavivirus transmitted mainly through Aedes spp. mosquitoes that is posing challenge to healthcare services in countries experiencing an outbreak. Usually ZIKV infection is mild, but in some cases it has been reported to progress into neurological diseases such as microcephaly in infants and Guillain-Barré syndrome (GBS) in adults. GBS is a debilitating autoimmune disorder that affects peripheral nerves. Since ZIKV caused massive outbreaks in South America in the past few years, we aimed to systematically review the literature and perform a meta-analysis to estimate the prevalence of GBS among ZIKV-infected individuals. We searched PubMed and Cochrane databases and selected three studies for a meta-analysis. We estimated the prevalence of ZIKV-associated GBS to be 1.23% (95% CI = 1.17–1.29%). Limitations include paucity of data regarding previous flavivirus infections and ZIKV-infection confirmation issues. Our estimate seems to be low, but cannot be ignored, since ZIKV outbreaks affects an overwhelming number of individuals and GBS is a life-threatening debilitating condition, especially in pregnant women. ZIKV infection cases must be closely followed to assure prompt care to reduce the impact of GBS associated-sequelae on the quality of life of those affected.

Emerging trends of Zika apprehension in an epidemic setting

Background

French Guiana is a territory that has a decades-long history of dengue outbreaks and more recently, in 2014, a chikungunya outbreak. Zika virus (ZIKV) emerged in late 2015 and subsequently led to an important outbreak.

Methodology/Principal findings

A cross-sectional phone survey was conducted among the general population during the outbreak in June 2016 with a total of 1,129 individuals interviewed to assess perceptions, knowledge and behaviors regarding zika infection. The population seemed aware of zika, and perceived the infection as a more serious health threat than other common mosquito-borne diseases. Furthermore, both the perceptions and behaviors related to zika and its prevention were found to vary considerably among different social groups, geographic areas and gender; less educated female participants were found to perceive the disease as more worrisome and were less likely to adopt protective behaviors. Moreover, female population has been particularly responsive to awareness campaigns and rapidly understood the extent of risks associated with ZIKV infection.

Conclusions/Significance

These results revealed that ZIKV appeared at the time of the survey as a new health threat that concerns the public more than chikungunya and dengue fever with differences observed among subgroups of population. These results have implications for the development of multifaceted infection control programs, including strategies for prevention and awareness, helping the population to develop an accurate perception of the threat they are facing and encouraging behavior changes.

Although dengue fever has been a focus of many awareness campaigns in Latin America, very little information is available about beliefs, attitudes and behaviors regarding vector-borne diseases among the population of French Guiana. Following the end of the first chikungunya outbreak and at the initial onset of the first zika outbreak, a quantitative survey was conducted among 1129 individuals aiming to study the emotional, cognitive and behavioral response to the risk of zika infection and assess variations among different groups of population. People from French Guiana were found to perceive zika substantially differently from other Aedes mosquito-borne diseases. Overall, ZIKV appeared at the time of the survey as a new health threat that makes the population more scared than chikungunya and dengue fever. Furthermore, both the beliefs and behaviors related to zika and its prevention were found to vary considerably among different social groups, gender and geographic areas. Education had an impact on perceptions and behaviors among women. Female population has been particularly responsive to awareness campaigns and rapidly understood the extent of risks associated with ZIKV infection. Overall, findings emphasize the importance of developing appropriate and relevant strategies helping population to engage in protective behaviors adapted to the health threat they are facing. Given the importance of the public response and precautionary actions to control the spread of an emergent threat, additional research on risk perceptions and other behavioral determinants is warranted.