Dengue during pregnancy and adverse fetal outcomes: a systematic review and meta-analysis

First clinical reports of acute hantavirus and dengue infections among pregnant women in the Caribbean

BACKGROUND

Hantavirus and dengue virus infections lead to diseases causing economic and public health concerns. Acute hantavirus infections can lead to similar clinical haemorrhagic signs as other endemic diseases including dengue and leptospirosis.

METHODS

Using a retrospective case analysis of pregnant dengue and hantavirus disease patients with clinical reports and compatible clinical laboratory information during pregnancy, we report the first evidence of dengue and hantavirus infections and a case of dual dengue and hantavirus infection among pregnant women in the Caribbean. Laboratory testing by enzyme-linked immunosorbent assay (ELISA) and non-structural protein 1 (NS1) for DENV and for hantavirus infection pseudotype focus reduction neutralisation tests (pFRNT), ELISA and immunochromatographic (ICG) strips.

RESULTS

Four pregnant cases with acute DENV infections were identified; however, only one out of the four cases (25%) had a detailed medical record to permit abstraction of clinical data. Six hantavirus infected pregnant cases were identified with gestation periods ranged from 36 to 39 weeks; none of the reported patients exhibited previous pregnancy complications prior to hospitalisation and infection. Acute liver damage was observed in three of the six cases (AST readings) who were subsequently diagnosed with hepatitis in pregnancy and variable clinical outcomes were observed with term and pre-term deliveries.

CONCLUSIONS

Whilst hantavirus infection in pregnancy is rare, consideration should be given to differential diagnosis with fever, kidney involvement, liver involvement, haemorrhagic symptoms and thrombocytopenia in endemic areas with clinically similar diseases such as dengue and leptospirosis.HighlightsFirst recorded case of hantavirus and dengue co-infection in a pregnant woman.First detailed report of clinical hantavirus infection in pregnant women in the Caribbean.First published report of clinical dengue infection in pregnant woman in the Caribbean.Possible complications of pregnancy following hantavirus infection.Pre-term birth and low birth weights.Clinical course of hantavirus infection in a Caribbean population.

Commonly Reported Mosquito-Borne Viruses in the United States: A Primer for Pharmacists

Mosquito-borne diseases are a public health concern. Pharmacists are often a patient's first stop for health information and may be asked questions regarding transmission, symptoms, and treatment of mosquito borne viruses (MBVs). The objective of this paper is to review transmission, geographic location, symptoms, diagnosis and treatment of MBVs. We discuss the following viruses with cases in the US in recent years: Dengue, West Nile, Chikungunya, LaCrosse Encephalitis, Eastern Equine Encephalitis Virus, and Zika. Prevention, including vaccines, and the impact of climate change are also discussed.

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.

Dengue

Dengue, caused by four closely related viruses, is a growing global public health concern, with outbreaks capable of overwhelming health-care systems and disrupting economies. Dengue is endemic in more than 100 countries across tropical and subtropical regions worldwide, and the expanding range of the mosquito vector, affected in part by climate change, increases risk in new areas such as Spain, Portugal, and the southern USA, while emerging evidence points to silent epidemics in Africa. Substantial advances in our understanding of the virus, immune responses, and disease progression have been made within the past decade. Novel interventions have emerged, including partially effective vaccines and innovative mosquito control strategies, although a reliable immune correlate of protection remains a challenge for the assessment of vaccines. These developments mark the beginning of a new era in dengue prevention and control, offering promise in addressing this pressing global health issue.

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.

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.

Vector-borne disease, climate change and perinatal health

Vector-borne diseases (VBDs) are caused by infectious pathogens that spread from an infected human or animal reservoir to an uninfected human via a vector (mosquito, tick, rodent, others) and remain an important cause of morbidity and mortality worldwide. Pregnant individuals and their fetuses are especially at risk, as certain pathogens, such as Zika virus, have specific implications in pregnancy and for neonatal health. Global climate change is affecting the incidence and geographic spread of many VBDs. Thus, it is important for clinicians in the fields of obstetrics/gynecology and newborn medicine, regardless of geographic location, to familiarize themselves with a basic understanding of these conditions and how climate change is altering their distributions. In this chapter, we review the incidence, clinical presentation, implications during pregnancy and intersection with climate change for four of the most important VBDs in pregnancy: malaria, Zika, dengue and Chagas disease. Although not exhaustive of all VBDs, a more extensive table is included for reference, and our discussion provides a helpful framework for understanding other vector-borne pathogens and perinatal health.

Arbovirus surveillance in pregnant women in north-central Nigeria, 2019-2022

BACKGROUND

The adverse impact of Zika (ZIKV), dengue (DENV), and chikungunya (CHIKV) virus infection in pregnancy has been recognized in Latin America and Asia but is not well studied in Africa. Although originally discovered in sub-Saharan Africa the non-specific clinical presentation of arbovirus infection may have hampered our detection of adverse clinical outcomes and outbreak.

OBJECTIVE

This prospective study of arbovirus infection in pregnant women in north-central Nigeria sought to characterize the prevalence of acute arbovirus infection and determine the impact on pregnancy and infant outcomes.

METHODS

In Nigeria, we screened 1006 pregnant women for ZIKV, DENV and CHIKV IgM/IgG by rapid test (2019-2022). Women with acute infection were recruited for prospective study and infants were examined for any abnormalities from delivery through six months. A subset of rapid test-reactive samples were confirmed using virus-specific ELISAs and neutralization assays.

RESULTS

The prevalence of acute infection (IgM+) was 3.8 %, 9.9 % and 11.8 % for ZIKV, DENV and CHIKV, respectively; co-infections represented 24.5 % of all infections. The prevalence in asymptomatic women was twice the level of symptomatic infection. We found a significant association between acute maternal ZIKV/DENV/CHIKV infection and any gross abnormal birth outcome (p = 0.014).

CONCLUSIONS

Over three rainy seasons, regular acute infection with ZIKV, DENV, and CHIKV was observed with significantly higher rates in pregnant women without symptoms. The potential association arbovirus infection with abnormal birth outcome warrants further prospective study to ascertain the clinical significance of these endemic arboviruses in Africa.

Hepatic damage caused by flaviviruses: A systematic review

Flaviviruses infect arthropods and mammals and their pathologies are a considerable global health problem, affecting about 400 million people per year. The symptoms of these flaviviruses range from mild manifestations such as nausea, vomiting, and headache to more serious cases such as hemorrhage, meningitis, microcephaly, kidney, and liver failure. This review aims to compile the morphological changes that occur due to infections caused by dengue, yellow fever, and Zika viruses, as well as to describe possible mechanisms of action of such flaviviruses in the liver. PRISMA guidelines were used to search for studies associating flavivirus with liver disorders. Two independent reviewers selected the studies on PubMed/Medline, Web of Science, and Scopus search platforms. The SYRCLE software was used for the evaluation of the study's quality. Eighteen experimental articles were included. The experimental animals often used in experiments were monkeys (5 %), hamsters (10 %), chicken embryos (10 %), and mice (75 %). It is evident that there is a strong hepatic interaction with flaviviruses, and the main hepatic alterations found were steatosis, apoptosis, necrosis, hemorrhage, elevation of ALT and AST levels, and total bilirubin. Flavivirus infection, in general, trigger an upregulation of pro-inflammatory cytokines, leading to structural changes in mitochondria that activate cascades of cellular death and promote insulin resistance. The majority of the studies primarily focus on dengue and yellow fever viruses, while the findings related to Zika virus exposure are still relatively limited and require further investigation.

The pregnant traveller: An overview of common preventable infections

Pregnant travellers are often unaware of the various infections that can be acquired during travel and that pregnant people may be at increased risk of severe disease compared to their non-pregnant counterparts. Pregnant people often seek pre-travel counselling from their obstetrician or primary care physicians, who may not be well versed in travel medicine. This paper aims to provide information for maternity care providers regarding important travel-related food, water and mosquito-borne illnesses, including their prevention and treatment methods, equipping maternity care providers to confidently counsel prospective travellers during pregnancy.

The Innate Immune Response in DENV- and CHIKV-Infected Placentas and the Consequences for the Fetuses: A Minireview

Dengue virus (DENV) and chikungunya (CHIKV) are arthropod-borne viruses belonging to the Flaviviridae and Togaviridae families, respectively. Infection by both viruses can lead to a mild indistinct fever or even lead to more severe forms of the diseases, which are characterized by a generalized inflammatory state and multiorgan involvement. Infected mothers are considered a high-risk group due to their immunosuppressed state and the possibility of vertical transmission. Thereby, infection by arboviruses during pregnancy portrays a major public health concern, especially in countries where epidemics of both diseases are regular and public health policies are left aside. Placental involvement during both infections has been already described and the presence of either DENV or CHIKV has been observed in constituent cells of the placenta. In spite of that, there is little knowledge regarding the intrinsic earlier immunological mechanisms that are developed by placental cells in response to infection by both arboviruses. Here, we approach some of the current information available in the literature about the exacerbated presence of cells involved in the innate immune defense of the placenta during DENV and CHIKV infections.

Neutrophil infiltration leads to fetal growth restriction by impairing the placental vasculature in DENV-infected pregnant mice

BACKGROUND

Dengue virus (DENV) infection during pregnancy increases the risk of adverse fetal outcomes, which has become a new clinical challenge. However, the underlying mechanism remains unknown.

METHODS

The effect of DENV-2 infection on fetuses was investigated using pregnant interferon α/β receptor-deficient (Ifnar1-/-) mice. The histopathological changes in the placentas were analyzed by morphological techniques. A mouse inflammation array was used to detect the cytokine and chemokine profiles in the serum and placenta. The infiltration characteristics of inflammatory cells in the placentas were evaluated by single-cell RNA sequencing.

FINDINGS

Fetal growth restriction observed in DENV-2 infection was mainly caused by the destruction of the placental vasculature rather than direct damage from the virus in our mouse model. After infection, neutrophil infiltration into the placenta disrupts the expression profile of matrix metalloproteinases, which leads to placental dysvascularization and insufficiency. Notably, similar histopathological changes were observed in the placentas from DENV-infected puerperae.

INTERPRETATION

Neutrophils play key roles in placental histopathological damage during DENV infection, which indicates that interfering with aberrant neutrophil infiltration into the placenta may be an important therapeutic target for adverse pregnancy outcomes in DENV infection.

FUNDING

The National Key Research and Development Plans of China (2021YFC2300200-02 to J.A., 2019YFC0121905 to Q.Z.C.), the National Natural Science Foundation of China (NSFC) (U1902210 and 81972979 to J. A., 81902048 to Z. Y. S., and 82172266 to P.G.W.), and the Support Project of High-level Teachers in Beijing Municipal Universities in the Period of 13th Five-year Plan, China (IDHT20190510 to J. A.).

Arboviral vaccines for use in pregnant travelers

Pregnant women traveling abroad can be exposed to a variety of arboviruses, primarily spread by mosquitoes or ticks. Some arboviral infections can be of particular concern for pregnant women or their fetuses. Vaccination is one preventive measure that can reduce the risk for infection. Several arboviral vaccines have been licensed for many years and can be used to prevent infection in travelers, namely Japanese encephalitis, yellow fever, and tick-borne encephalitis vaccines. Recommendations on use of these vaccines in pregnancy vary. Other arboviral vaccines have been licensed but are not indicated for use in pregnant travelers (e.g., dengue vaccines) or are in development (e.g., chikungunya, Zika vaccines). This review describes arboviral vaccines for travelers, focusing on women who are pregnant and those planning travel during pregnancy.

Arbovirus surveillance in pregnant women in north-central Nigeria, 2019-2022

The adverse impact of Zika (ZIKV), dengue (DENV), and chikungunya (CHIKV) virus infection in pregnancy has been recognized in Latin America and Asia but is not well studied in Africa. In Nigeria, we screened 1006 pregnant women for ZIKV, DENV and CHIKV IgM/IgG by rapid test (2019-2022). Women with acute infection were recruited for prospective study and infants were examined for any abnormalities from delivery through six months. A subset of rapid test-reactive samples were confirmed using virus-specific ELISAs and neutralization assays. Prevalence of acute infection (IgM+) was 3.8%, 9.9% and 11.8% for ZIKV, DENV and CHIKV, respectively; co-infections represented 24.5% of all infections. Prevalence in asymptomatic women was twice the level of symptomatic infection. We found a significant association between acute maternal ZIKV/DENV/CHIKV infection and any gross abnormal birth outcome (p=0.014). Further prospective studies will contribute to our understanding of the clinical significance of these endemic arboviruses in Africa.

Adenovirus vector produced Zika virus-like particles induce a long-lived neutralising antibody response in mice

Countermeasures against Zika virus (ZIKV) epidemics are urgently needed. In this study we generated a ZIKV virus-like particle (VLP) based vaccine candidate and assessed the immunogenicity of these particles in mice. The ZIKV-VLPs were morphologically similar to ZIKV by electron microscopy and were recognized by anti-Flavivirus neutralising antibodies. We observed that a single dose of unadjuvanted ZIKV-VLPs, or inactivated ZIKV, generated an immune response that lasted over 6 months, but did not neutralize ZIKV infection of cells in vitro. However, when we co-administered the ZIKV VLPs with either Aluminium hydroxide (Alhydrogel®; Alum), AddaVax or Pam₂Cys we observed that Alum was the most effective in a single dose regime, since it not only produced antibodies that neutralized the virus, but also generated a greater number of antigen-specific memory B cells. We additionally observed that the generation of the neutralising antibodies persisted for up to 6 months. Our results suggest that a single dose ZIKV VLPs could be a suitable single dose vaccine candidate for use in outbreak settings.

Mice as an Animal Model for Japanese Encephalitis Virus Research: Mouse Susceptibility, Infection Route, and Viral Pathogenesis

Japanese encephalitis virus (JEV), a zoonotic flavivirus, is principally transmitted by hematophagous mosquitoes, continually between susceptible animals and incidentally from those animals to humans. For almost a century since its discovery, JEV was geographically confined to the Asia-Pacific region with recurrent sizable outbreaks involving wildlife, livestock, and people. However, over the past decade, it has been detected for the first time in Europe (Italy) and Africa (Angola) but has yet to cause any recognizable outbreaks in humans. JEV infection leads to a broad spectrum of clinical outcomes, ranging from asymptomatic conditions to self-limiting febrile illnesses to life-threatening neurological complications, particularly Japanese encephalitis (JE). No clinically proven antiviral drugs are available to treat the development and progression of JE. There are, however, several live and killed vaccines that have been commercialized to prevent the infection and transmission of JEV, yet this virus remains the main cause of acute encephalitis syndrome with high morbidity and mortality among children in the endemic regions. Therefore, significant research efforts have been directed toward understanding the neuropathogenesis of JE to facilitate the development of effective treatments for the disease. Thus far, multiple laboratory animal models have been established for the study of JEV infection. In this review, we focus on mice, the most extensively used animal model for JEV research, and summarize the major findings on mouse susceptibility, infection route, and viral pathogenesis reported in the past and present, and discuss some unanswered key questions for future studies.

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.

INCIDENCE, CAUSES, AND RISK FACTORS OF STILLBIRTH IN AN AMAZONIAN CONTEXT: SAINT LAURENT DU MARONI MATERNITY WARD 2016-2021

Objective

We aimed to describe the epidemiology of intrauterine fetal deaths in multiethnic western French Guiana and to assess its main causes and risk factors.

Study design

A retrospective descriptive study was conducted based on data from January 2016 to December 2021. All information on stillbirth with a gestational age ≥20 weeks in the Western French Guiana Hospital Center was extracted. Terminations of pregnancy were excluded. We focused on medical history, clinical investigation, biological findings, placental histology, and autopsy examination to elucidate the cause of death. We used the Initial Cause of Fetal Death (INCODE) classification system for assessment. Univariable and multivariable logistic regression analyses were performed.

Results

Overall, 331 fetuses in 318 stillbirth deliveries were reviewed and compared to live births that occurred during the same period. The rate of fetal death varied between 1.3 % and 2.1 %, with an average of 1.8 % over the 6-year period. Poor antenatal care (104/318, 32.7 %), obesity ≥30 kg/m² (88/318, 31.7 %), and preeclampsia (59/318, 18.5 %) were the main risk factors associated with fetal death in this group. Four hypertensive crises were reported. According to the INCODE classification, the main causes of fetal death were obstetric complications (112/331, 33.8 %), particularly intrapartum fetal death with labor-associated asphyxia under 26 weeks (64/112, 57.1 %), and placental abruption (29/112, 25.9 %). Maternal-fetal infections were common, particularly mosquito-borne diseases (e.g., Zika virus, dengue, and malaria), re-emerging infectious agents such as syphilis, and severe maternal infections (8/331, 2.4 %). 19.3 % of fetal deaths (64/331) remained unexplained.

Conclusion

Change in lifestyle as well as social deprivation and isolation adversely affect pregnancy in western French Guiana, in the context of a poor health care system that is similar to what is found in the Amazonian basin. Particular attention must be paid to emerging infectious agents in pregnant women and travelers returning from the Amazon region.

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.

Clinical and experimental evidence for transplacental vertical transmission of flaviviruses

The Zika virus (ZIKV) epidemic outbreak in Americas in 2016 attracted global attention because of the association of the virus infection with severe birth defects such as microcephaly, mediated through transplacental virus transmission during pregnancy. Less well-known, but also reported is the increasing evidence that prenatal vertical transmission can be caused by other flaviviruses such as dengue virus (DENV). Currently, the mechanism(s) that cause the vertical transmission of flaviviruses is understudied. Here we review the published reports of clinical evidence of intrauterine transmission of ZIKV and other flaviviruses. We also discuss the animal models for flavivirus infection during pregnancy that have been developed to study the mechanisms underlying the transplacental transmission of flaviviruses in order to develop potential countermeasures for its prevention.

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.

Perinatal Transmission of Dengue Infection among Dengue Hemorrhagic Fever Outbreaks in Southern Vietnam: The First Case Managed at Tu Du Hospital and Review of Literature

Dengue hemorrhagic fever is a high-risk pathology in pregnancy, leading to an increased mortality rate for both the mother and baby. Perinatal transmission of dengue infection may occur during the labor stage of the febrile phase, despite its extreme rarity. In the present case, a young female patient with pregnancy at 39 weeks 3 days of gestational age was hospitalized because of dengue hemorrhagic fever. Upon monitoring, her platelet count gradually decreased to a very low of 13,000 mm3 on the third day of fever. However, her platelet count increased soon afterwards. On the eighth day of admission, she was delivered by emergency cesarean section due to acute fetal distress. The female neonate was promptly assessed by the pediatric team upon cesarean surgery. The neonate was diagnosed with vertical transmission of dengue infection based on positive dengue virus nonstructural protein 1 antigen, and low platelet count was found on the first day postpartum. When there is a high suspicion of perinatal transmission, closely monitoring the newborn helps to avoid the adverse outcomes and mortality for the infant. Herein, we thoroughly report an unusual case of maternal-fetal transmission of dengue during pregnancy at our maternity hospital.

Susceptibility to endemic Aedes-borne viruses among pregnant women in Risaralda, Colombia

OBJECTIVE

Aedes-borne viruses (ABV) affect humans on every inhabited continent and frequently cause epidemics. Recent epidemics of chikungunya and Zika viruses highlight that preparedness for future epidemics requires assessment of susceptibility, particularly among high-risk groups. We sought to determine immunity against the three major circulating ABV among pregnant women in an ABV-endemic area of Colombia.

METHODS

A cross-sectional seroprevalence study was performed, enrolling women presenting to Labor and Delivery. Cord blood and maternal peripheral blood was obtained. IgG seroprevalence to flaviviruses and chikungunya was determined by ELISA. An abbreviated neutralization test was used to estimate the frequency and magnitude of immunity to Zika and four dengue serotypes. Cluster analyses explored epidemiologic factors associated with seroprevalence.

RESULTS

Most women exhibited high levels of neutralizing antibodies to one or more ABV; however, nearly 20% were seronegative for flaviviruses. Our research took place after the epidemic peak of the ZIKV outbreak in Colombia in 2016, but only 20% of pregnant women had high levels of Zika-neutralizing antibodies consistent with likely protective immunity to ZIKV.

CONCLUSIONS

Hence, a high proportion pregnant women in Risaralda remain susceptible to one or more ABV including the teratogenic ZIKV, indicating risk for future epidemics in this region.

Global prevalence of dengue and chikungunya coinfection: A systematic review and meta-analysis of 43,341 participants

Dengue and chikungunya virus are important arboviruses of public health concern. In the past decades, they have accounted for numerous outbreaks of dengue and chikungunya in different parts of the world. Several cases of concurrent infection of dengue and chikungunya have been documented. However, the true burden of this concurrent infection is unknown. Here, a systematic review and meta-analysis of published data on the prevalence of dengue and chikungunya coinfection in the human population was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. Six electronic databases (Web of science, Embase, PubMed, ScienceDirect, Scopus, and Google Scholar) were searched without year or language restrictions for relevant studies. The study protocol was registered with PROSPERO (CRD42020175344). Eighty-three studies involving a total of 43,341 participants were included. The random-effects model was employed to calculate the summary estimates. A pooled global prevalence of 2.5% (95% CI: 1.8-3.4) was obtained for dengue and chikungunya coinfection. Males and females appear to be coinfected at a fairly similar rate. Among the regions, Asia accounted for the highest prevalence (3.3%, 95% CI: 2.3-4.6) while North America was the least (0.8%, 95% CI: 0.3-2.4). The prevalence estimates varied across different countries. A much higher prevalence rates were obtained for Colombia (37.4%, 95% CI: 9.1-78.1), Madagascar (18.2%, 95% CI: 10.1-30.6), Laos (12.5%, 95% CI: 5.3-26.7), Maldives (4.5%, 95% CI: 1.5-13.0) and Thailand (3.7%, 95% CI: 0.4-26.3). This first extensive systematic review and meta-analysis reveals dengue and chikungunya coinfection as a global problem worthy of consideration. It is therefore pertinent that both infections be assessed during diagnosis, mosquito vector control practices be implemented, and vaccine development strides be supported globally.

Effects of Acute Dengue Infection on Sperm and Virus Clearance in Body Fluids of Men

We investigated the effects of dengue virus (DENV) on semen using samples collected 7, 15, 30, 60, and 90 days after symptom onset from 10 infected volunteers on Réunion Island. We assessed characteristics of semen and reproductive hormones and isolated motile spermatozoa from semen. We assayed semen for DENV using reverse transcription PCR and searched for DENV RNA by virus isolation in Vero E6 cell cultures. Four volunteers had >1 DENV RNA-positive semen samples; 2 volunteers had DENV RNA–positive semen at day 15 and 1 at day 30. No motile sperm were DENV positive. After exposure to positive semen, few Vero E6 cells stained positive for DENV antigens, indicating low levels of replicative virus. We found DENV had shorter duration in semen than in blood. These findings support the possibilities that DENV is sexually transmissible for a short period after acute dengue illness and that acute dengue induces reversible alterations in sperm.

Role of structural disorder in the multi-functionality of flavivirus proteins

INTRODUCTION

The life cycle of a virus involves interacting with the host cell, entry, hijacking host machinery for viral replication, evading the host's immune system, and releasing mature virions. However, viruses, being small in size, can only harbor a genome large enough to code for the minimal number of proteins required for the replication and maturation of the virions. As a result, many viral proteins are multifunctional machines that do not directly obey the classic structure-function paradigm. Often, such multifunctionality is rooted in intrinsic disorder that allows viral proteins to interact with various cellular factors and remain functional in the hostile environment of different cellular compartments.

AREAS COVERED

This report covers the classification of flaviviruses, their proteome organization, and the prevalence of intrinsic disorder in the proteomes of different flaviviruses. Further, we have summarized the speculations made about the apparent roles of intrinsic disorder in the observed multifunctionality of flaviviral proteins.

EXPERT OPINION

Small sizes of viral genomes impose multifunctionality on their proteins, which is dependent on the excessive usage of intrinsic disorder. In fact, intrinsic disorder serves as a universal functional tool, weapon, and armor of viruses and clearly plays an important role in their functionality and evolution.

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

Background

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

Methods

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

Findings

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

Interpretation

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

Funding

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

Mosquito-borne disease and newborn health

While mosquito-borne diseases are currently most prevalent in mid-latitude countries, rising global temperatures could expand their range. This paper investigates whether one such disease, dengue, harms newborns. The empirical design exploits epidemiological patterns of the disease spreading. Dengue infection rates in the mother's municipality of residence which prevailed during the gestation period are instrumented with exogenous factors that determine dengue incidence in municipalities that have tight social connections to the maternal municipality. Using a large longitudinal dataset of Brazilian birth records, I find that a higher dengue rate during the third trimester of gestation has a detrimental effect on birth weight. In utero exposure to dengue also increases the probability of cesarean delivery and can lead to more serious consequences such as increased fetal and maternal mortality rates.

The Seroprevalence of Dengue Virus Infection and Its Association With Iron (Fe) Level in Pregnant Women in Guangzhou, China

Dengue fever is regarded as the most prevalent mosquito-borne viral disease in humans. However, information of dengue virus (DENV) infection in pregnant women and the influence factors remain unclear. In this study, we extracted information of 2,076 pregnant women from the Prenatal Environment and Offspring Health (PEOH) birth cohort conducted since 2016 in Guangzhou, China. Peripheral blood and clean midstream urine samples of participants were collected during their hospitalization for childbirth. Indirect enzyme-linked immunosorbent assay (ELISA) was used to detect immunoglobulin G (IgG) antibodies of DENV in serum samples, and inductively coupled plasma mass spectrometry (ICP-MS) was applied to determine the Fe concentrations in the urine samples, which were then adjusted for by urine creatinine and transformed by natural logarithm (ln-Fe). The seroprevalence of DENV IgG antibody in all included participants was 2.22% (46/2,076). We observed higher seroprevalence of IgG antibody in women aged ≥35 years (2.9%), education ≤ 12 years (2.5%), yearly income per capita <100,000 yuan (2.4%), no use of air-conditioner (2.4%), no use of mosquito coils (2.3%), and no exercise during pregnancy (4.1%). A U-shaped relationship was found between ln-Fe concentration and the risk of positive IgG antibody. Compared with women with ln-Fe concentration of 2.0–2.9 μg/g creatinine, slightly higher risks of positive IgG antibody were found among women with ≤2.0 (RR = 4.16, 95% CI: 0.78, 19.91), 3.0–3.9 (RR = 1.93, 95% CI: 0.65, 7.08), 4.0–4.9 (RR = 2.19, 95% CI: 0.65, 8.51), and ≥5.0 μg/g creatinine of ln-Fe (RR = 2.42, 95% CI: 0.46, 11.33). Our findings suggested that the seroprevalence of dengue IgG antibody in pregnant women was comparable to the general population in Guangzhou, China. The risk of DENV infection may be associated with maternal demographic characteristics and behaviors. Both maternal low and high Fe concentrations may be positively associated with the risk of DENV infection.

[Clinical complications during pregnancy: a systematic review of studies with pregnant Brazilian women]

The scope of this paper was to describe the main clinical complications among pregnant Brazilian women reported in the literature, identifying the most relevant exposure factors and their outcomes in maternal and child health. This is a systematic review of articles published between 2010 and 2018. Three reviews and 36 empirical articles were included; mental disorders (n=9), infectious diseases (n=9) and severe maternal morbidity (n=8) were the main clinical complications during pregnancy. In addition, four articles focused on determining the main conditions or causes of hospitalization, with a higher frequency of Urinary Tract Infection, anemia and hypertensive diseases. Maternal age at reproductive extremes, lower schooling, socioeconomic vulnerability, racial characteristics and the use of public health services were the most relevant exposure factors. Unfavorable health outcomes associated with clinical complications in pregnancy were verified in the eight articles with this profile. The frequency of pregnant women with potential life-threatening clinical complications is high in the country, highlighting the importance of primary care coverage and the implementation of interventions to reduce and prevent adverse maternal and child outcomes.

Adverse pregnancy outcomes during the COVID-19 lockdown. A descriptive study

BACKGROUND

The ongoing spread coronavirus disease worldwide has caused major disruptions and led to lockdowns. Everyday lifestyle changes and antenatal care inaccessibility during the coronavirus disease 2019 (COVID-19) pandemic have variable results that affect pregnancy outcomes. This study aimed to assess the alterations in stillbirth, neonatal-perinatal mortality, preterm birth, and birth weight during the COVID-19 national lockdown.

METHODS

We used the data from the Jordan stillbirths and neonatal death surveillance system to compare pregnancy outcomes (gestational age, birth weight, small for gestational age, stillbirth, neonatal death, and perinatal death) between two studied periods (11 months before the pandemic (May 2019 to March 2020) vs. 9 months during the pandemic (April 2020 to March 1st 2020). Separate multinomial logistic and binary logistic regression models were used to compare the studied outcomes between the two studied periods after adjusting for the effects of mother's age, income, education, occupation, nationality, health sector, and multiplicity.

RESULTS

There were 31106 registered babies during the study period; among them, 15311 (49.2%) and 15795 (50.8%) births occurred before and during the COVID-19 lockdown, respectively. We found no significant differences in preterm birth and stillbirth rates, neonatal mortality, or perinatal mortality before and during the COVID-19 lockdown. Our findings report a significantly lower incidence of extreme low birth weight (ELBW) infants (<1kg) during the COVID-19 lockdown period than that before the lockdown (adjusted OR 0.39, 95% CI 0.3-0.5: P value <0.001) CONCLUSIONS: During the COVID-19 lockdown period, the number of infants born with extreme low birth weight (ELBW) decreased significantly. More research is needed to determine the impact of cumulative socio-environmental and maternal behavioral changes that occurred during the pandemic on the factors that contribute to ELBW infants.

Serological Markers of Viral Infections (Rubella Virus, Human Cytomegalovirus and Arboviruses) among Symptomatic Pregnant Women in Rural and Urban Areas of Mwanza, Tanzania

Viral infections have been associated with poor pregnancy outcomes. We investigated the magnitude of rubella virus (RV), dengue virus (DENV), Zika virus (ZIKV) and human cytomegalovirus (HCMV) among symptomatic pregnant women in rural and urban areas of Mwanza. A cross-sectional study was conducted between July 2017 and April 2018 in Mwanza. A rapid immunochromatographic test was done to detect ZIKV IgM and IgG as well as DENV IgM and IgG antibodies. A multiplex_RT-PCR was also done to detect the viral RNA genome. Enzyme immunoassays were done to detect RV and HCMV. Out of 171 participants, 1 (0.6%) was found to be seropositive for ZIKV_IgM antibodies, while 5 (2.9%) were ZIKV_IgG seropositive. DENV seropositivity was 9 (5.3%) and 3 (1.8%) for IgM and IgG, respectively, with all being PCR negative. Two participants (1.2%) were RV_IgM seropositive. 100% were HCMV_IgG seropositive and none was HCMV_IgM seropositive. Among 70 women with high HCMV_IgG titters, 10 (14.3%) had a low avidity index, indicating recent infections. Residing in rural areas (p = 0.044) and advanced age (p = 0.024) independently predicted ZIKV/DENV seropositivity. A substantial proportion of pregnant women had markers for viral infections. There is a need for introducing routine screening and monitoring pregnancy outcomes of positive cases to establish the relationship of these viruses and adverse pregnancy outcomes in endemic areas.

Fever During Pregnancy: Etiology and Fetomaternal Outcomes

Purpose

Etiological spectrum of fever in pregnant women and its impact on fetomaternal outcomes were studied.

Methods

This was a hospital-based prospective study, conducted over 12 months. All pregnant women with fever were screened and detailed etiological evaluation carried out. Maternal and foetal outcomes were noted.

Results

One hundred and eighty-one pregnant women with fever were included. Common causes were dengue 44 (24.3%), hepatitis E 26 (14.4%) and urinary tract infection (UTI) 22 (12.2%). Mosquito-borne diseases accounted for the highest burden 61 (33.7%). Second most common were diseases transmitted by feco-oral route 46 (25.4%). Maternal deaths occurred in 29 (16%) patients. Common causes of death were hepatitis E infection in 9 of 26 (34.6%) cases, dengue in 7 of 44 (15.9%) and tuberculosis in 5 of 11 (45.5%) cases.

Conclusion

Dengue, hepatitis E and UTI were the most common causes of fever during pregnancy. Most cases were caused by vector- and water-borne diseases and thus potentially preventable. Overall maternal mortality was 16%.

Perinatal Outcomes Among Patients With Sepsis During Pregnancy

IMPORTANCE

Rates of maternal sepsis are increasing, and prior studies of maternal sepsis have focused on immediate maternal morbidity and mortality associated with sepsis during delivery admission. There are no data on pregnancy outcomes among individuals who recover from their infections prior to delivery.

OBJECTIVE

To describe perinatal outcomes among patients with antepartum sepsis who did not deliver during their infection hospitalization.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study was conducted using data from August 1, 2012, to August 1, 2018, at an academic referral center in San Francisco, California. Included patients were all individuals with nonanomalous, singleton pregnancies who delivered after 20 weeks' gestation during the study period. Data were analyzed from March 2020 through March 2021.

EXPOSURES

Antepartum admission for infection with clinical concern for sepsis and hospital discharge prior to delivery.

MAIN OUTCOMES AND MEASURES

The primary outcome was a composite of perinatal outcomes associated with placental dysfunction and consisted of 1 or more of the following: fetal growth restriction, oligohydramnios, hypertensive disease of pregnancy, cesarean delivery for fetal indication, child who is small for gestational age, or stillbirth.

RESULTS

Among 14 565 patients with nonanomalous singleton pregnancies (mean [SD] age at delivery, 33.1 [5.2] years), 59 individuals (0.4%) were in the sepsis group and 14 506 individuals (99.6%) were in the nonsepsis group; 8533 individuals (59.0%) were nulliparous. Patients with sepsis, compared with patients in the reference group, were younger (mean [SD] age at delivery, 30.6 [5.7] years vs 33.1 [5.2] years; P < .001), were more likely to have pregestational diabetes (5 individuals [8.5%] vs 233 individuals [1.6%]; P = .003), and had higher mean (SD) pregestational body mass index scores (26.1 [6.1] vs 24.4 [5.9]; P = .03). In the sepsis group, the most common infections were urinary tract infections (24 patients [40.7%]) and pulmonary infections (22 patients [37.3%]). Among patients with sepsis, 5 individuals (8.5%) were admitted to the intensive care unit, the mean (SD) gestational age at infection was 24.6 (9.0) weeks, and the median (interquartile range) time from infection to delivery was 82 (42-147) days. Antepartum sepsis was associated with higher odds of placental dysfunction (21 patients [35.6%] vs 3450 patients [23.8%]; odds ratio, 1.77; 95% CI, 1.04-3.02; P = .04). On multivariable logistic regression analysis, antepartum sepsis was an independent factor associated with placental dysfunction (adjusted odds ratio, 1.88; 95% CI, 1.10-3.23; P = .02) after adjusting for possible confounders.

CONCLUSIONS AND RELEVANCE

This study found that pregnancies complicated by antepartum sepsis were associated with higher odds of placental dysfunction. These findings suggest that increased antenatal surveillance should be considered for these patients.

Diagnosis of dengue fever in a patient with early pregnancy loss

Dengue is a mosquito-borne virus that causes an influenza-like illness ranging in severity from asymptomatic to fatal. Dengue in pregnancy has been associated with adverse outcomes including miscarriage, preterm birth and fetal and neonatal death. We present the case of a multiparous woman who presented at 9 weeks' gestation with vaginal bleeding and abdominal cramping after a 1 month stay in Mexico. She was initially diagnosed with miscarriage with plan for outpatient follow-up. She was readmitted 3 days later with fever, retro-orbital pain, arthralgia, rash, pancytopenia and transaminitis and managed with intravenous fluids and acetaminophen. Of note, dengue serology was initially negative but retesting 2 days later was positive. It is imperative that clinicians have heightened suspicion for dengue in pregnant women with history of travel to or residence in a dengue-endemic area and consistent clinical evidence.

Risk factors for hospitalization and mortality due to dengue fever in a Mexican population: a retrospective cohort study

OBJECTIVES

Identify risk factors associated with increased hospital admission and mortality due to dengue fever (DF), and estimate the risk magnitude associated with each individual variable.

METHODS

Records of patients diagnosed with dengue were obtained from the Mexican National Epidemiological Surveillance System. Descriptive statistics were performed in all variables. Demographic characteristics and comorbidities were compared between patients based on type of care and mortality. Multivariable analysis was done with a logistic regression model, using two different outcomes: hospitalization and mortality.

RESULTS

A total of 24,495 patients were included in the analysis, with a DF case fatality rate of 0.58%. Patients younger than 10 and older than 60, were found to have a greater risk of both hospitalization and mortality due to DF. Comorbidities associated with a higher risk for hospital admission include cirrhosis, CKD, immunosuppression, diabetes, and hypertension. For mortality, CKD, diabetes, and hypertension were identified as risk factors, along with pregnancy.

CONCLUSION

Identification of risk factors associated with increased hospitalization and mortality due to DF can help categorize patients that require close monitoring and inpatient care. Early identification of warning signs and patients at increased risk is key to avoiding delay of supportive care.

Neutrophil Recruitment and Participation in Severe Diseases Caused by Flavivirus Infection

Neutrophils are first-line responders to infections and are recruited to target tissues through the action of chemoattractant molecules, such as chemokines. Neutrophils are crucial for the control of bacterial and fungal infections, but their role in the context of viral infections has been understudied. Flaviviruses are important human viral pathogens transmitted by arthropods. Infection with a flavivirus may result in a variety of complex disease manifestations, including hemorrhagic fever, encephalitis or congenital malformations. Our understanding of flaviviral diseases is incomplete, and so is the role of neutrophils in such diseases. Here we present a comprehensive overview on the participation of neutrophils in severe disease forms evolving from flavivirus infection, focusing on the role of chemokines and their receptors as main drivers of neutrophil function. Neutrophil activation during viral infection was shown to interfere in viral replication through effector functions, but the resulting inflammation is significant and may be detrimental to the host. For congenital infections in humans, neutrophil recruitment mediated by CXCL8 would be catastrophic. Evidence suggests that control of neutrophil recruitment to flavivirus-infected tissues may reduce immunopathology in experimental models and patients, with minimal loss to viral clearance. Further investigation on the roles of neutrophils in flaviviral infections may reveal unappreciated functions of this leukocyte population while increasing our understanding of flaviviral disease pathogenesis in its multiple forms.

Epidemiology and challenges of dengue surveillance in the WHO South-East Asia Region

Dengue poses a significant health and economic burden in the WHO South-East Asia Region. Approaches for control need to be aligned with current knowledge on the epidemiology of dengue in the region. Such knowledge will ensure improved targeting of interventions to reduce dengue incidence and its socioeconomic impact. This review was undertaken to describe the contemporary epidemiology of dengue and critically analyse the existing surveillance strategies in the region. Over recent decades, dengue incidence has continued to increase with geographical expansion. The region has now become hyper-endemic for multiple dengue virus serotypes/genotypes. Every epidemic cycle was associated with a change of predominant serotype/genotype and this was often associated with severe disease with intense transmission. Classical larval indices are widely used in vector surveillance and adult mosquito samplings are not implemented as a part of routine surveillance. Further, there is a lack of integration of entomological and disease surveillance systems, often leading to inaction or delays in dengue prevention and control. Disease surveillance does not capture all cases, resulting in under-reporting, and has thus failed to adequately represent the true burden of disease in the region. Possible solutions include incorporating adult mosquito sampling into routine vector surveillance, the establishment of laboratory-based sentinel surveillance, integrated vector and dengue disease surveillance and climate-based early warning systems using available technologies like mobile apps.

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.

Evidence that hematopoietic stem cells in human umbilical cord blood is infectable by dengue virus: proposing a vertical transmission candidate

Background

Recent studies have shown that dengue virus (DENV) can efficiently infect bone marrow hematopoietic stem cells (HSCs) as well as the placenta of pregnant women. Although mother-to-infant vertical transmission of DENV through the placenta has been well documented, the evidence of cell-associated vertical transmission is still unknown. Whether DENV can infect umbilical cord blood (UCB) cells before reaching the fetus remains to be explored. Here, we proposed that human UCB cells were permissive to the DENV infection and DENV infected CD133+ and CD34+ HSCs are reservoir of the virus that could be reactivated upon re-culturing in suitable cells.

Methods

Human UCB cells were freshly obtained and subjected to DENV infection. Multicolor flow cytometry (MFCM) was used to demonstrate the phenotypes of the infected HSC populations. Immunofluorescence analysis (IFA) and T-distributed Stochastic Neighbor Embedding (t-SNE) were used to show the association of the DENV antigen, non-structural protein1 (NS1) with HSCs.

Key findings

UCB cells were highly permissive to DENV infection. DENV altered the phenotype of the infected HSC population, increased the expression of HSCs, and affected the balance of transcription factors (TFs, GATA1/2/3). IFA revealed the association of the DENV antigen, non-structural protein1 (NS1), with CD34⁺ and CD133⁺ cells. T-distributed Stochastic Neighbor Embedding (t-SNE) analysis revealed heterogeneity in the distribution of CD133⁺NS1⁺, and CD34⁺ NS1⁺ cells. DENV particles were recovered from CD133⁺ and CD34⁺ cells even when virus production in the supernatant was negligible.

Significance

We predict that infection of CD133+ and CD34+ cells in the UCB serve as reservoirs for the amplification of DENV in UCB prior to the virus reaching the fetus and facilitate vertical transmission.

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.

COVID-19 During Development: A Matter of Concern

A new infectious disease, COVID-19, has spread around the world. The most common symptoms of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are cough and fever, but severe cases can develop acute respiratory distress syndrome. The main receptor for SARS-CoV-2 in human tissue is angiotensin-converting enzyme 2, and the lungs, heart, and kidneys are the most affected organs. Besides the inflammatory process and tissue damage, the presence of a cytokine "storm" has been related to a higher mortality rate. Other infectious viral diseases, such as Zika, chikungunya, and influenza, were associated with complications in pregnant women, such as growth restriction, malformation, preterm birth, low birth weight, miscarriage, and death, although they can also cause developmental disorders in infants and adolescents. Evidence points out that stressors during pregnancy and infancy may lead to the development of obesity, diabetes, and cardiovascular disease. Therefore, we hypothesize that COVID-19 infection during the critical phases of development can program the individual to chronic diseases in adulthood. It is important that COVID-19 patients receive proper monitoring as a way to avoid expensive costs to public health in the future.

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.

Improved Aedes/dengue field surveillance using Gravid Oviposition Sticky trap and dengue NS1 tests: Epidemiological, entomological outcomes and community acceptance

The aim of this study is to investigate the feasibility and outcomes of using Gravid Oviposition Sticky (GOS) trap and dengue NS1 antigen tests for indoor and outdoor dengue/Aedes surveillance in the field. A one-year community-based study was carried out at Sungai Buloh Hospital Quarters, Selangor, Malaysia. GOS traps were first placed outdoors in three apartment blocks (Anggerik, Bunga Raya and Mawar). Beginning 29th week of the study, indoor traps were set in two apartment units on every floor in Anggerik. All female Aedes mosquitoes caught were tested for the presence of dengue NS1 antigen. Dengue seroprevalence and knowledge, attitude and practices on dengue prevention of the community and their reception to the surveillance approach were also assessed. Dengue-positive mosquitoes were detected at least 1 week before a dengue onset. More mosquitoes were caught indoors than outdoors in block Anggerik, but the total number of mosquitoes caught in all 3 blocks were similar. There was a significant difference in distribution of Ae. aegypti and Ae. albopictus between the 3 blocks. 66.1% and 3.4% of the community were positive for dengue IgG and IgM, respectively. Most respondents think that this surveillance method is Good (89%) and support its use nationwide. Dengue case ratio in the study apartment blocks decreased from year 2018 to 2019. This study demonstrated the practicality of performing proactive dengue/Aedes surveillance inside apartment units using the GOS traps. This surveillance method can be performed with immediate result output in the field.

Clinical features and outcomes of neonatal dengue at the Children's Hospital 1, Ho Chi Minh, Vietnam

Objectives Neonatal dengue has been reported in the literature with contradictory findings of clinical characteristics and diagnosis; thereby, misdiagnosis of neonatal dengue has been frequently reported. We aim to delve into the epidemiology, clinical features, and outcomes of neonatal dengue, thus avoid misdiagnosis and obtain early intervention. Study design A retrospective study was conducted at Children's Hospital 1, Ho Chi Minh, Vietnam with laboratory-confirmed dengue in neonates by positive viral antigen nonstructural protein one rapid test (NS1) and positive IgM antibody for dengue by MAC-ELISA. Results We have included 32 neonates in this study with 25% cases were misdiagnosed with neonatal sepsis, and 12.5% cases were misdiagnosed with neonatal immune thrombocytopenia at the beginning. The median time between the first day of the mother's onset of fever and childbirth was -1 days (IQR: -2, 2). The patient's clinical manifestation included: petechiae 87.5% (28/32), pharyngeal mucosal hemorrhage 6.3% (2/32), and hepatomegaly occurred 75% (24/32). In the febrile phase (day of illness 1-3), the mean white blood cell (WBC) counts were 7800 ± 800/mm³ and platelets were 97,111 ± 37,826/mm³. In the critical phase (day of illness 4-6), the mean WBC counts were 13,400 ± 2800/mm³, and platelets were 30,100 ± 5749/mm³. All mothers (100%) had laboratory-confirmed dengue by NS1 positive in the perinatal period. Conclusions The findings emphasize that early diagnosis of neonatal dengue should be based on a history of maternal illness, NS1 rapid test, and clinical presentation such as petechiae, hepatomegaly, and low platelet counts in the febrile phase.

Maternal and fetal outcomes of dengue fever in pregnancy: a large prospective and descriptive observational study

Purpose

The primary objective of the study was to assess maternal and fetal outcomes of pregnancies affected with dengue fever.

Methods

This was a prospective, observational and descriptive study carried out over a period of 1 year. 216 pregnant women with fever were screened. Of these, 44 women tested positive for dengue (non-structural protein antigen 1 or dengue IgM antibodies in the sera). The clinical and laboratory characteristics of women with dengue were recorded. Maternal outcomes, pregnancy outcomes and fetal outcomes were studied.

Results

Mean period of gestation was 31.89 ± 7.31 weeks. Thrombocytopenia was seen in 23 (52.3%) women. Of 40 women, 10 (25%) developed post-partum haemorrhage. The incidence of maternal systemic complications was high: eight (18.2%) women developed acute kidney injury and two (4.5%) required haemodialysis support; eight (18.2%) women developed ARDS and seven (15.9%) women required ventilatory support; four (9.1%) women developed acute liver failure. 18 (40.9%) women had evidence of shock. Seven (15.9%) women died and another seven (15.9%) were classified as WHO maternal near-miss cases. Two (4.5%) pregnancies suffered from miscarriages, four (9%) from still births and two (4.5%) from neonatal deaths. Preterm babies were delivered in 15 (34.1%) and low birth weight babies in 13 (29.5%).

Conclusions

Dengue in pregnancy adversely affects maternal and fetal outcomes with high maternal mortality of 15.9%. Prematurity and postpartum haemorrhage are significant risks to mother and baby. Vector control strategies should be implemented with vigour in affected areas.

Climate change and declining fertility rate in Malaysia: the possible connexions

Climate change is an incessant global phenomenon and has turned contentious in the present century. Malaysia, a developing Asian country, has also undergone significant vicissitudes in climate, which has been projected with significant deviations in forthcoming decades. As per the available studies, climate changes may impact on the fertility, either via direct effects on the gonadal functions and neuroendocrine regulations or via several indirect effects on health, socioeconomic status, demeaning the quality of food and water. Malaysia is already observing a declining trend in the Total fertility rate (TFR) over the past few decades and is currently recorded below the replacement level of 2.1 which is insufficient to replace the present population. Moreover, climate changes reportedly play a role in the emergence and cessation of various infectious diseases. Besides its immediate effects, the long-term effects on health and fertility await to be unveiled. Despite the huge magnitude of the repercussion of climate changes in Malaysia, research that can explain the exact cause of the present reduction in fertility parameters in Malaysia or any measures to preserve the national population is surprisingly very scarce. Thus, the present review aims to elucidate the possible missing links by which climate changes are impairing fertility status in Malaysia.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Neurological Findings in Children without Congenital Microcephaly Exposed to Zika Virus in Utero: A Case Series Study

The Zika virus can induce a disruptive sequence in the fetal brain and is manifested mainly by microcephaly. Knowledge gaps still exist as to whether the virus can cause minor disorders that are perceived later on during the first years of life in children who are exposed but are asymptomatic at birth. In this case series, we describe the outcomes related to neurodevelopment through the neurological assessment of 26 non-microcephalic children who had intrauterine exposure to Zika virus. Children were submitted for neurological examinations and Bayley Scales-III (cognition, language, and motor performance). The majority (65.4%) obtained satisfactory performance in neurodevelopment. The most impaired domain was language, with 30.7% impairment. Severe neurological disorders occurred in five children (19.2%) and these were spastic hemiparesis, epilepsy associated with congenital macrocephaly (Zika and human immunodeficiency virus), two cases of autism (one exposed to Zika and Toxoplasma gondii) and progressive sensorineural hearing loss (GJB2 mutation). We concluded that non-microcephalic children with intrauterine exposure to Zika virus, in their majority, had achieved satisfactory performance in all neurodevelopmental domains. One third of the cases had some impairment, but the predominant group had mild alterations, with low occurrence of moderate to severe disorders, similar to other studies in Brazil.