Symptomatic Dengue during Pregnancy and Congenital Neurologic Malformations

Perinatal dengue and Zika virus cross-sectional seroprevalence and maternal-fetal outcomes among El Salvadoran women presenting for labor-and-delivery

BACKGROUND

Despite maternal flavivirus infections' linkage to severe maternal and fetal outcomes, surveillance during pregnancy remains limited globally. Further complicating maternal screening for these potentially teratogenic pathogens is the overwhelming subclinical nature of acute infection. This study aimed to understand perinatal and neonatal risk for poor health outcomes associated with flaviviral infection during pregnancy in El Salvador.

METHODS

Banked serologic samples and clinical results obtained from women presenting for labor and delivery at a national referent hospital in western El Salvador March to September 2022 were used for this study. 198 samples were screened for dengue and Zika virus IgM, and statistical analyses analyzed demographic and clinical outcome associations with IgM positivity.

RESULTS

This serosurvey revealed a high rate of maternal flavivirus infection-24.2% of women presenting for labor and delivery were dengue or Zika virus IgM positive, suggesting potential infection within pregnancy. Specifically, 20.2% were Zika virus IgM positive, 1.5% were dengue virus IgM positive, and 2.5% were both dengue and Zika virus IgM positive. Women whose home had received mosquito abatement assistance within the last year by the ministry of health were 70% less likely to test IgM positive (aOR = 0.30, 95%CI: 0.10, 0.83). Further, statistical geospatial clustering revealed transmission foci in six primary municipalities. Pregnancy complications and poor birth outcomes were noted among the dengue and/or Zika virus maternal infection group, although these outcomes were not statistically different than the seronegative group. None of the resulting neonates born during this study were diagnosed with congenital Zika syndrome.

CONCLUSIONS

The high rate of Zika virus detected among pregnant women and the lack of Zika-specific neonatal outcomes monitoring during a non-outbreak year highlights the need for continued surveillance in Central America and among immigrant mothers presenting for childbirth from these countries. As changing climatic conditions continue to expand the range of the disease vector, asymptomatic screening programs could be vital to early identification of outbreaks and clinical management of cases.

Severe dengue in the intensive care unit

Dengue fever is considered the most prolific vector-borne disease in the world, with its transmission rate increasing more than eight times in the last two decades. While most cases present mild to moderate symptoms, 5% of patients can develop severe disease. Although the mechanisms are yet not fully comprehended, immune-mediated activation leading to excessive cytokine expression is suggested as a cause of the two main findings in critical patients: increased vascular permeability that may shock and thrombocytopenia, and coagulopathy that can induce hemorrhage. The risk factors of severe disease include previous infection by a different serotype, specific genotypes associated with more efficient replication, certain genetic polymorphisms, and comorbidities such as diabetes, obesity, and cardiovascular disease. The World Health Organization recommends careful monitoring and prompt hospitalization of patients with warning signs or propensity for severe disease to reduce mortality. This review aims to update the diagnosis and management of patients with severe dengue in the intensive care unit.

The impact of anthropogenic climate change on pediatric viral diseases

The adverse effects of climate change on human health are unfolding in real time. Environmental fragmentation is amplifying spillover of viruses from wildlife to humans. Increasing temperatures are expanding mosquito and tick habitats, introducing vector-borne viruses into immunologically susceptible populations. More frequent flooding is spreading water-borne viral pathogens, while prolonged droughts reduce regional capacity to prevent and respond to disease outbreaks with adequate water, sanitation, and hygiene resources. Worsening air quality and altered transmission seasons due to an increasingly volatile climate may exacerbate the impacts of respiratory viruses. Furthermore, both extreme weather events and long-term climate variation are causing the destruction of health systems and large-scale migrations, reshaping health care delivery in the face of an evolving global burden of viral disease. Because of their immunological immaturity, differences in physiology (e.g., size), dependence on caregivers, and behavioral traits, children are particularly vulnerable to climate change. This investigation into the unique pediatric viral threats posed by an increasingly inhospitable world elucidates potential avenues of targeted programming and uncovers future research questions to effect equitable, actionable change. IMPACT: A review of the effects of climate change on viral threats to pediatric health, including zoonotic, vector-borne, water-borne, and respiratory viruses, as well as distal threats related to climate-induced migration and health systems. A unique focus on viruses offers a more in-depth look at the effect of climate change on vector competence, viral particle survival, co-morbidities, and host behavior. An examination of children as a particularly vulnerable population provokes programming tailored to their unique set of vulnerabilities and encourages reflection on equitable climate adaptation frameworks.

Neurological Manifestations of Perinatal Dengue

Dengue viruses (DENVs) are single-stranded RNA viruses belonging to the family Flaviviridae. There are four distinct antigenically related serotypes, DENVs types 1, 2, 3, and 4. These are all mosquito-borne human pathogens. Congenital dengue disease occurs when there is mother-to-fetus transmission of the virus and should be suspected in endemic regions in neonates presenting with fever, maculopapular rash, and thrombocytopenia. Although most of the infected infants remain asymptomatic, some can develop clinical manifestations such as sepsis-like illness, gastric bleeding, circulatory failure, and death. Neurological manifestations include intracerebral hemorrhages, neurological malformations, and acute focal/disseminated encephalitis/encephalomyelitis. Dengue NS1Ag, a highly conserved glycoprotein, can help the detection of cases in the viremic stage. We do not have proven specific therapies yet; management is largely supportive and is focused on close monitoring and maintaining adequate intravascular volume.

Identifying hidden Zika hotspots in Pernambuco, Brazil: a spatial analysis

BACKGROUND

Northeast Brazil has the world's highest rate of Zika-related microcephaly. However, Zika case counts cannot accurately describe burden because mandatory reporting was only established when the epidemic was declining in the region.

METHODS

To advance the study of the Zika epidemic, we identified hotspots of Zika in Pernambuco state, Northeast Brazil, using Aedes-borne diseases (dengue, chikungunya and Zika) and microcephaly data. We used Kulldorff's Poisson purely spatial scan statistic to detect low- and high-risk clusters for Aedes-borne diseases (2014-2017) and for microcephaly (2015-2017), separately. Municipalities were classified according to a proposed gradient of Zika burden during the epidemic, based on the combination of cluster status in each analysis and considering the strength of the evidence.

RESULTS

We identified 26 Aedes-borne diseases clusters (11 high-risk) and 5 microcephaly clusters (3 high-risk) in Pernambuco. According to the proposed Zika burden gradient, our results indicate that the northeast of Pernambuco and the Sertão region were hit hardest by the Zika epidemic. The first is the most populous area of Pernambuco, while the second has one of the highest rates of social and economic inequality in Brazil.

CONCLUSION

We successfully identified possible hidden Zika hotspots using a simple methodology combining Aedes-borne diseases and microcephaly information.

TORCH Congenital Syndrome Infections in Central America's Northern Triangle

TORCH pathogens are a group of globally prevalent infectious agents that may cross the placental barrier, causing severe negative sequalae in neonates, including fetal death and lifelong morbidity. TORCH infections are classically defined by Toxoplasma gondii, other infectious causes of concern (e.g., syphilis, Zika virus, malaria, human immunodeficiency virus), rubella virus, cytomegalovirus, and herpes simplex viruses. Neonatal disorders and congenital birth defects are the leading causes of neonatal mortality in Central America's Northern Triangle, yet little is known about TORCH congenital syndrome in this region. This review synthesizes the little that is known regarding the most salient TORCH infections among pregnant women and neonates in Central America's Northern Triangle and highlights gaps in the literature that warrant further research. Due to the limited publicly available information, this review includes both peer-reviewed published literature and university professional degree theses. Further large-scale studies should be conducted to clarify the public health impact these infections in this world region.

Exploring the Expression and Function of cTyro3, a Candidate Zika Virus Receptor, in the Embryonic Chicken Brain and Inner Ear

The transmembrane protein Axl was proposed as an entry receptor for Zika virus (ZIKV) infection in vitro, but conflicting results from in vivo studies have made it difficult to establish Axl as a physiologically relevant ZIKV receptor. Both the functional redundancy of receptors and the experimental model used can lead to variable results. Therefore, it can be informative to explore alternative animal models to analyze ZIKV receptor candidates as an aid in discovering antivirals. This study used chicken embryos to examine the role of chicken Tyro3 (cTyro3), the equivalent of human Axl. Results show that endogenous cTyro3 mRNA expression overlaps with previously described hot spots of ZIKV infectivity in the brain and inner ear. We asked if ectopic expression or knockdown of cTyro3 influenced ZIKV infection in embryos. Tol2 vectors or replication-competent avian retroviruses were used in ovo to introduce full-length or truncated (presumed dominant-negative) cTyro3, respectively, into the neural tube on embryonic day two (E2). ZIKV was delivered to the brain 24 h later. cTyro3 manipulations did not alter ZIKV infection or cell death in the E5/E6 brain. Moreover, delivery of truncated cTyro3 variants to the E3 otocyst had no effect on inner ear formation on E6 or E10.

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.

Arboviral Infections in Neurological Disorders in Hospitalized Patients in São José do Rio Preto, São Paulo, Brazil

Arbovirus infections are increasingly important causes of disease, whose spectrum of neurological manifestations are not fully known. This study sought to retrospectively assess the incidence of arboviruses in cerebrospinal fluid samples of patients with neurological symptoms to inform diagnosis of central and peripheral nervous system disorders. A total of 255 cerebrospinal fluid (CSF) samples collected from January 2016 to December 2017 were tested for dengue virus (DENV 1-4), Zika virus (ZIKV), and Chikungunya virus (CHIKV) in addition to other neurotropic arboviruses of interest, using genetic and serologic assays. Of the 255 CSF samples analyzed, 3.53% (09/255) were positive for arboviruses presenting mainly as meningitis, encephalitis, and cerebrovascular events, of which ZIKV was detected in 2.74% (7/255), DENV in 0.78% (2/255), in addition to an identified ILHV infection that was described previously. All the cases were detected in adults aged 18 to 74 years old. Our findings highlight the scientific and clinical importance of neurological syndromes associated with arboviruses and demonstrate the relevance of specific laboratory methods to achieve accurate diagnoses as well as highlight the true dimension of these diseases to ultimately improve public health planning and medical case management.

Human Brain Organoids as Models for Central Nervous System Viral Infection

Pathogenesis of viral infections of the central nervous system (CNS) is poorly understood, and this is partly due to the limitations of currently used preclinical models. Brain organoid models can overcome some of these limitations, as they are generated from human derived stem cells, differentiated in three dimensions (3D), and can mimic human neurodevelopmental characteristics. Therefore, brain organoids have been increasingly used as brain models in research on various viruses, such as Zika virus, severe acute respiratory syndrome coronavirus 2, human cytomegalovirus, and herpes simplex virus. Brain organoids allow for the study of viral tropism, the effect of infection on organoid function, size, and cytoarchitecture, as well as innate immune response; therefore, they provide valuable insight into the pathogenesis of neurotropic viral infections and testing of antivirals in a physiological model. In this review, we summarize the results of studies on viral CNS infection in brain organoids, and we demonstrate the broad application and benefits of using a human 3D model in virology research. At the same time, we describe the limitations of the studies in brain organoids, such as the heterogeneity in organoid generation protocols and age at infection, which result in differences in results between studies, as well as the lack of microglia and a blood brain barrier.

Association between maternal infections during pregnancy and congenital defects in their offspring: a population-based case-control study in Bogota and Cali, Colombia 2001-2018

Infections are frequent during pregnancy and their teratogenic role is well documented in Toxoplasmosis, other infections, Rubella, Cytomegalovirus, and Herpes simplex (TORCH). However, the in-utero development effects of the rest of the infections that affect pregnant women are unknown. We described a cohort of patients with major Birth Defects (BD) and the exposure to infections during pregnancy from the information of Congenital Defects Surveillance Programs of two Colombian cities (Bogota and Cali) between 2001 and 2018. We evaluated associations between groups of maternal infections and BD among 3096 cases and 7446 controls that were registered. BD presentation was more frequent as isolated (64.3%), polymalformed (23.2%), and syndromic (12.4%). Infections during pregnancy were present in 52.5% of cases and 44.6% of controls. The most common single infection between cases and controls was vaginal infection. The most common polyinfection was vaginal and urinary tract infection. We found an association between BD and vaginal infections with an odds ratio (OR) 1.18 (CI 1.08-1.30), urinary tract infections OR 1.16 (CI 1.05-1.28), gastrointestinal infections OR 2.06 (IC 1.18-3.59), respiratory infections OR 1.56 (IC 1.28-1.9) and viral infections OR 1.88 (IC 1.18-3.0). Knowing the teratogenic effect of infections is important to extend prevention, screening, timely diagnosis, and appropriate treatment to pregnant women.

Imported Arbovirus Infections in Spain, 2009-2018

To determine the epidemiologic and clinical characteristics of patients in Spain with imported arbovirus infections, we analyzed 22,655 records from a collaborative network for January 2009-December 2018. Among 861 arbovirus infections, 845 were monoinfections (456 [53%] dengue, 280 [32.5%] chikungunya, 109 [12.7%] Zika) and 16 (1.8%) were co-infections. Most patients were travelers (56.3%) or immigrants returning to Spain after visiting friends or relatives (31.3%). Median patient age was 37 years; most (62.3%) were women and some (28.6%) had received pretravel advice. Only 12 patients were immunosuppressed. Six cases (all dengue monoinfections, none in immunosuppressed patients) were severe. Since 2014, nondengue arbovirus infections increased; until 2016, chikungunya and Zika were most common. Imported arbovirus infections (mostly dengue) were frequently diagnosed, although increased chikungunya and Zika virus infections coincided with their introduction and spread in the Americas. A large proportion of cases occurred in women of childbearing age, some despite receipt of pretravel advice.

Ebola, Dengue, Chikungunya, and Zika Infections in Neonates and Infants

Emerging infectious diseases, including Ebola, chikungunya, Zika, and dengue, may have significant impacts on maternal-fetal dyads and neonatal outcomes. Pregnant women infected with Ebola demonstrate high mortality and very low evidence of neonatal survival. Maternal chikungunya infection can result in high rates of perinatal transmission, and infected neonates demonstrate variable disease severity. Dengue can be transmitted to neonates via vertical transmission or perinatal transmission. Zika is characterized by mild disease in pregnant women, but congenital infection can be severe. Treatment largely is supportive for these diseases, and vaccine development remains under way, with promising recent advances, notably for Ebola.

Congenital dengue in a Saudi neonate: A case report

BACKGROUND

Dengue fever is a mosquito-borne viral illness with 100 million new cases occurring worldwide. The vectors involved are mainly Aedes aegypti and Aedes albopictus. Dengue infection is associated with maternal as well as fetal morbidities, like stillbirth, preterm birth, and low birth weight.

THE CASE

We report a case of dengue fever occurring during early pregnancy and subsequent congenital neurologic malformation in the neonate as a result of vertical transmission. To our knowledge, this is the first case of confirmed congenital dengue in Saudi Arabia.

DISCUSSION

Dengue infection is not commonly associated with congenital anomalies and no biologic mechanism has yet been established for its teratogenicity. Congenital dengue in neonates can be confirmed by identification of the dengue virus in cord blood samples. The positive dengue serology within the first week of life, together with the confirmed maternal dengue infection during pregnancy, supports the diagnosis of vertical transmission in the presence of clinical manifestations. A high index of suspicion, early diagnosis, and close monitoring is needed in these cases.

Neonatal Outcomes From Arboviruses in the Perinatal Period: A State-of-the-Art Review

Since the 2016 Zika outbreak and the understanding of the teratogenic effect of this infection, there has been a newfound interest in arbovirus infections and their effects on pregnancy, resulting in numerous publications in the last 5 years. However, limited literature focuses on arbovirus infection in different stages of pregnancy and their effect on the neonate. There is currently no consensus management of perinatal acquisition of arboviruses, and current evidence is largely anecdotal observational reports. Teratogens can have different effects on the developing fetus depending on the time of infection, so infections during pregnancy should be analyzed by trimester. A better understanding of arbovirus infection in the perinatal period is required to assist obstetric, neonatal, and pediatric clinicians in making decisions about the management of mother and neonate. Our objective was to assess the evidence of adverse neonatal outcomes for several arboviral infections when contracted during the perinatal period to guide clinicians in managing these patients. There are 8 arboviruses for which neonatal outcomes from maternal acquisition in the perinatal period have been reported, with the most data for dengue and Chikungunya virus infections. The evidence reviewed in this article supports the adoption of preventive strategies to avoid ticks and mosquitoes close to the date of delivery. For the other arbovirus infections, further community-based cohort studies during outbreaks are required to evaluate whether these infections have a similar teratogenic impact.

The limited knowledge of placental damage due to neglected infections: ongoing problems in Latin America

The placenta works as a selective barrier, protecting the fetus from potential infections that may affect the maternal organism during pregnancy. In this review, we will discuss several challenging infections that are common within Latin American countries and that may affect the maternal-fetal interface and pose risks to fetal development. Specifically, we will focus on emerging infectious diseases including the arboviruses, malaria, leishmaniasis, and the bacterial foodborne disease caused by Shiga toxin-producing Escherichia coli. We will also highlight some topics of interest currently being studied by research groups that comprise an international effort aimed at filling the knowledge gaps in this field. These topics address the relationship between exposure to microorganisms and placental abnormalities, congenital anomalies, and complications of pregnancy.

ABBREVIATIONS

ADE: antibody-dependent enhancement; CCL2: monocyte chemoattractant protein-1; CCL3: macrophage inflammatory protein-1 α; CCL5: chemokine (C-C motif) ligand 5; CHIKV: chikungunya virus; DCL: diffuse cutaneous leishmaniasis; DENV: dengue virus; Gb3: glycolipid globotriaosylceramyde; HIF: hypoxia-inducible factor; HUS: hemolytic uremic syndrome; IFN: interferon; Ig: immunoglobulins; IL: interleukin; IUGR: intrauterine growth restriction; LCL: localized cutaneous leishmaniasis; LPS: lipopolysaccharid; MCL: mucocutaneous leishmaniasis; NO: nitric oxide; PCR: polymerase chain reaction; PGF: placental growth factor; PM: placental malaria; RIVATREM: Red Iberoamericana de Alteraciones Vasculares em transtornos del Embarazo; sVEGFR: soluble vascular endothelial growth factor receptor; STEC: shiga toxin-producing Escherichia coli; stx: shiga toxin protein; TNF: tumor necrosis factor; TOAS: T cell original antigenic sin; Var2CSA: variant surface antigen 2-CSA; VEGF: vascular endothelial growth factor; VL: visceral leishmaniasis; WHO: world health organization; YFV: yellow fever virus; ZIKV: Zika virus.

Stop, think SCORTCH: rethinking the traditional 'TORCH' screen in an era of re-emerging syphilis

BACKGROUND

The epidemiology of congenital infections is ever changing, with a recent resurgence in syphilis infection rates seen in the UK. Identification of congenital infection is often delayed; early recognition and management of congenital infections is important. Testing modalities and investigations are often limited, leading to missed diagnostic opportunities.

METHODS

The SCORTCH (syphilis, cytomegalovirus (CMV), 'other', rubella, toxoplasmosis, chickenpox, herpes simplex virus (HSV) and blood-borne viruses) acronym increases the awareness of clinicians to the increased risk of congenital syphilis, while considering other infectious aetiologies including: zika, malaria, chagas disease, parvovirus, enterovirus, HIV, hepatitis B and C, and human T-lymphotropic virus 1, in addition to the classic congenital infections recognised in the 'TORCH screen' (toxoplasmosis, 'other', rubella, CMV, HSV). The SCORTCH diagnostic approach describes common signs present in infants with congenital infection, details serological testing for mother and infant and important direct diagnostics of the infant. Direct diagnostic investigations include: radiology, ophthalmology, audiology, microbiological and PCR testing for both the infant and placental tissue, the latter also warrants histopathology.

CONCLUSION

The traditional 'TORCH screen' focuses on serology-specific investigations, often omits important direct diagnostic testing of the infant, and fails to consider emerging and re-emerging congenital infections. In recognition of syphilis as a re-emerging pathogen and the overlapping clinical presentations of various infectious aetiologies, we advocate for a broader outlook using the SCORTCH diagnostic approach.

Zika virus infection in pregnancy: a protocol for the joint analysis of the prospective cohort studies of the ZIKAlliance, ZikaPLAN and ZIKAction consortia

INTRODUCTION

Zika virus (ZIKV) infection in pregnancy has been associated with microcephaly and severe neurological damage to the fetus. Our aim is to document the risks of adverse pregnancy and birth outcomes and the prevalence of laboratory markers of congenital infection in deliveries to women experiencing ZIKV infection during pregnancy, using data from European Commission-funded prospective cohort studies in 20 centres in 11 countries across Latin America and the Caribbean.

METHODS AND ANALYSIS

We will carry out a centre-by-centre analysis of the risks of adverse pregnancy and birth outcomes, comparing women with confirmed and suspected ZIKV infection in pregnancy to those with no evidence of infection in pregnancy. We will document the proportion of deliveries in which laboratory markers of congenital infection were present. Finally, we will investigate the associations of trimester of maternal infection in pregnancy, presence or absence of maternal symptoms of acute ZIKV infection and previous flavivirus infections with adverse outcomes and with markers of congenital infection. Centre-specific estimates will be pooled using a two-stage approach.

ETHICS AND DISSEMINATION

Ethical approval was obtained at each centre. Findings will be presented at international conferences and published in peer-reviewed open access journals and discussed with local public health officials and representatives of the national Ministries of Health, Pan American Health Organization and WHO involved with ZIKV prevention and control activities.

Neurocognitive impacts of arbovirus infections

Arthropod-borne viruses or arbovirus, are most commonly associated with acute infections, resulting on various symptoms ranging from mild fever to more severe disorders such as hemorrhagic fever. Moreover, some arboviral infections can be associated with important neuroinflammation that can trigger neurological disorders including encephalitis, paralysis, ophthalmological impairments, or developmental defects, which in some cases, can lead to long-term defects of the central nervous system (CNS). This is well illustrated in Zika virus-associated congenital brain malformations but also in West Nile virus-induced synaptic dysfunctions that can last well beyond infection and lead to cognitive deficits. Here, we summarize clinical and mechanistic data reporting on cognitive disturbances triggered by arboviral infections, which may highlight growing public health issues spanning the five continents.

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.

Severe dengue in travellers: pathogenesis, risk and clinical management

RATIONALE FOR REVIEW

Dengue is a frequent cause of febrile illness among travellers and has overtaken malaria as the leading cause of febrile illness for those traveling to Southeast Asia. The purpose is to review the risk of dengue and severe dengue in travellers with a particular focus on the pathogenesis and clinical management of severe dengue.

RISK, PATHOGENESIS AND CLINICAL MANAGEMENT

The risk of travel-acquired dengue depends on destination, season and duration of travel and activities during travel. Seroconversion rates reported in travellers, therefore, vary between <1% and >20%. The most common life-threatening clinical response to dengue infection is the dengue vascular permeability syndrome, epidemiologically linked to secondary infection, but can also occur in primary infection. Tertiary and quaternary infections are usually associated with mild or no disease. Antibody-dependent enhancement, viral factors, age, host factors and clinical experience of the managing physician modulate the risk of progressing to severe dengue. The relative risk of severe dengue in secondary versus primary infection ranges from 2 to 7. The absolute risk of severe dengue in children in highly endemic areas is ~0.1% per year for primary infections and 0.4% for secondary infections. About 2-4% of secondary infections lead to severe dengue. Severe dengue and death are both relatively rare in general travellers but more frequently in those visiting friends and relatives. Clinical management of severe dengue depends on judicious use of fluid rehydration.

CONCLUSIONS

Although dengue is a frequent cause of travel illness, severe dengue and deaths are rare. Nevertheless, dengue infections can interrupt travel and lead to evacuation and major out-of-pocket costs. Dengue is more frequent than many other travel-related vaccine preventable diseases, such as hepatitis A, hepatitis B, rabies, Japanese encephalitis and yellow fever, indicating a need for a dengue vaccine for travellers.

Simultaneous circulation of arboviruses and other congenital infections in pregnant women in Rio de Janeiro, Brazil

BACKGROUND

Arboviruses (Zika, dengue and chikungunya) represent a major risk for pregnant women, especially because their vertical transmission can lead to neurological damage in newborns. Early diagnosis can be difficult due to similar clinical presentation with other congenital infections that are associated with congenital abnormalities.

OBJECTIVES

To investigate the circulation of arboviruses and other pathogens responsible for congenital infections, reporting clinical aspects and geographic distribution of maternal rash in a metropolitan region of Rio de Janeiro (Brazil).

METHODS

Cross-sectional study with pregnant women presenting rash attended at the Exanthematic Diseases Unit (Niterói, Rio de Janeiro) from 2015 to 2018. Diagnosis of arboviruses was performed by real-time PCR (RT-qPCR) and laboratorial screening for syphilis, toxoplasmosis, rubella, cytomegalovirus and HIV was assessed. Demographic data was used for georeferencing analysis.

FINDINGS

We included 121 pregnant women, of whom Zika virus was detected in 45 cases (37.2%), chikungunya in 33 (27.3%) and dengue in one (0.8%). Five patients presented syphilis, and we observed one case each of listeria, cytomegalovirus, and a syphilis-toxoplasmosis case. Similarity of clinical symptoms was observed in all groups; however, 84.8% of patients with chikungunya presented arthralgia. Following the decline of Zika cases, chikungunya infection was mostly observed during 2017-2018. Considering pregnant women infected with arboviruses and other infections, 41% resided in urban slums, mostly in Niterói.

MAIN CONCLUSIONS

Simultaneous circulation of arboviruses and other agents responsible for congenital infections were observed; however, we did not identify co-infections between arboviruses. In this scenario, we emphasize the importance of adequate prenatal care to provide an accurate diagnosis of maternal rash.

Assessment of the effectiveness of BG-Sentinel traps baited with CO2 and BG-Lure for the surveillance of vector mosquitoes in Miami-Dade County, Florida

Vector-borne diseases are an increasing issue to public health, endangering billions of people worldwide. Controlling vector mosquitoes is widely accepted as the most effective way to prevent vector-borne disease outbreaks. Mosquito surveillance is critical for the development of control strategies under the integrated vector management framework. We hypothesize that the effectiveness and reliability of using BG-Sentinel traps for the surveillance strongly depend on the bait used to attract mosquitoes. The objective of this study was to compare the effectiveness of BG-Sentinel traps baited with CO2 and BG-Lure. A total of 72 traps were deployed for 48 hours once a week for four weeks. For the initial 24-hour period, the traps were baited with CO2, and then for an additional 24 hours using the BG-Lure. Collected mosquitoes were analyzed using the Generalized Estimating Equation for repeated measures analysis. Biodiversity was assessed by the Shannon and Simpson indices and by individual rarefaction curves and SHE profiles. A total of 5,154 mosquitoes were collected, from which 3,514 by traps baited with CO2 and 1,640 mosquitoes by traps baited with BG-Lure. Aedes aegypti and Culex quinquefasciatus were the most abundant and dominant species. Results from the Generalized Estimating Equation models indicated that more than twice as many mosquitoes were attracted CO2 than to the BG-Lure. The comparison of attractiveness of CO2 and BG-Lure to Ae. aegypti and Cx. quinquefasciatus was non-significant, suggesting that both species were equally attracted by the baits. The individual rarefaction curves for Ae. aegypti and Cx. quinquefasciatus imply that traps baited with BG-Lure underestimated mosquito species richness compared to those baited with CO2. BG-Lure were less effective in attracting mosquitoes with low abundances and failed to collect Cx. coronator and Cx. nigripalpus, which were consistently collected by traps baited with CO2. According to our results, CO2 significantly (P<0.05) attracted more mosquitoes (2.67 adjusted odds ratios) than the BG-Lure when adjusted for time and species, being more effective in assessing the relative abundance of vector mosquitoes and yielding more trustworthy results. Traps baited with CO2 collected not only more specimens, but also more species in a more consistent pattern.