Parvovirus B19 infection in pregnancy: new insights and management

Genotypic Characterization of Human Parvovirus B19 Circulating in the 2024 Outbreak in Tuscany, Italy

Human Parvovirus B19 (hB19V) is a widespread virus, causing erythema infectiosum in children and several clinical manifestations from acute to persistent infections in adults. In early 2024, ECDC reported an increased human Parvovirus B19 circulation in 14 European countries. A hB19V outbreak was also reported in Tuscany, Italy, prompting a detailed investigation of its genetic characteristics. In this context, through strict monitoring of circulating strains via next-generation sequencing (NGS), we carried out a phylogenetic analysis based on the whole of hB19V genomes. Phylogenetic clustering assigned all isolates to the G1a genotype, although with some mutations in NS1, VP1, and VP2, compared to the reference strains. Further characterization of these variants is necessary to fully assess their potential implications for public health. This study provides valuable insights into the spread of Parvovirus B19 and underlines the importance of continuous genomic surveillance to monitor and respond to possible hB19V epidemics that could impact public health.

Congenital infectious encephalopathies from the intrapartum period to postnatal life

Congenital infections are a common but often underrecognized cause of fetal brain abnormalities, as well as fetal-neonatal morbidity and mortality, that should be considered by all healthcare professionals providing neurological care to fetuses and newborns. Maternal infection with various pathogens (cytomegalovirus, Toxoplasmosis, Rubella virus, Parvovirus B19, lymphocytic choriomeningitis virus, syphilis, Zika virus, varicella zoster virus) during pregnancy can be transmitted to the developing fetus, which can cause multisystem dysfunction and destructive or malformative central nervous system lesions. These can be recognized on fetal and neonatal imaging, including ultrasound and MRI. Imaging and clinical features often overlap, but some distinguishing features can help identify specific pathogens and guide subsequent testing strategies. Some pathogens can be specifically treated, and others can be managed with targeted interventions or symptomatic therapy based on expected complications. Neurological and neurodevelopmental complications related to congenital infections vary widely and are likely driven by a combination of pathophysiologic factors, alone or in combination. These include direct invasion of the fetal central nervous system by pathogens, inflammation of the maternal-placental-fetal triad in response to infection, and long-term effects of immunogenic and epigenetic changes in the fetus in response to maternal-fetal infection. Congenital infections and their neurodevelopmental impacts should be seen as an issue of public health policy, given that infection and the associated complications disproportionately affect woman and children from low- and middle-income countries and those with lower socio-economic status in high-income countries. Congenital infections may be preventable and treatable, which can improve long-term neurodevelopmental outcomes in children.

Parvovirus B19 Outbreak in Israel: Retrospective Molecular Analysis from 2010 to 2023

This study presents an analysis of the epidemiological trends of parvovirus B19 (B19V) in Israel from 2010 to 2023, with particular emphasis on the outbreak in 2023. The analysis utilized molecular diagnostic data from individual patients obtained at the Central Virology Laboratory. Between 2010 and 2022, 8.5% of PCR-tested samples were positive for B19V, whereas in 2023, this percentage surged to 31% of PCR-tested samples. Throughout the study period, annual cycles consistently peaked in early spring/summer, with the most recent prominent outbreak occurring in 2016. Predominantly, diagnoses were made in children and women aged 20-39. Despite the notable surge in 2023, over 80% of positive cases continued to be observed in children and young women, with a decrease in cases during winter months. Furthermore, genotype 1a of the virus remained the predominant strain circulating during the outbreak. In light of these circumstances, consideration should be given to implementing screening measures, particularly among high-risk groups such as pregnant women.

Parvovirus B19 Infection and Pregnancy: Review of the Current Knowledge

Parvovirus B19, a member of the Parvoviridae family, is a human pathogenic virus. It can be transmitted by respiratory secretions, hand-to-mouth contact, blood transfusion, or transplacental transmission. Most patients are asymptomatic or present with mild symptoms such as erythema infectiosum, especially in children. In rare cases, moderate-to-severe symptoms may occur, affecting blood cells and other systems, resulting in anemia, thrombocytopenia, and neutropenia. Non-immune pregnant women are at risk for fetal infection by parvovirus B19, with greater complications if transmission occurs in the first or second trimester. Infected fetuses may not show any abnormalities in most cases, but in more severe cases, there may be severe fetal anemia, hydrops, and even pregnancy loss. Maternal diagnosis of intrauterine parvovirus B19 infection includes IgG and IgM antibody testing. For fetal diagnosis, PCR is performed through amniocentesis. In addition to diagnosing the infection, it is important to monitor the peak of systolic velocity of the middle cerebral artery (PVS-MCA) Doppler to assess the presence of fetal anemia. There is no vaccine for parvovirus B19, and fetal management focuses on detecting moderate/severe anemia by fetal PVS-MCA Doppler, which, if diagnosed, should be treated with intrauterine transfusion by cordocentesis. Prevention focuses on reducing exposure in high-risk populations, particularly pregnant women.

Gestational Viral Infections: Role of Host Immune System

Viral infections in pregnancy are major causes of maternal and fetal morbidity and mortality. Infections can develop in the neonate transplacentally, perinatally, or postnatally (from breast milk or other sources) and lead to different clinical manifestations, depending on the viral agent and the gestational age at exposure. Viewing the peculiar tolerogenic status which characterizes pregnancy, viruses could exploit this peculiar immunological status to spread or affect the maternal immune system, adopting several evasion strategies. In fact, both DNA and RNA virus might have a deep impact on both innate and acquired immune systems. For this reason, investigating the interaction with these pathogens and the host's immune system during pregnancy is crucial not only for the development of most effective therapies and diagnosis but mostly for prevention. In this review, we will analyze some of the most important DNA and RNA viruses related to gestational infections.

Intrauterine Blood Transfusion for Parvo B19-Induced Fetal Anemia: Neuroimaging Findings and Long-Term Neurological Outcomes

INTRODUCTION

We aimed to evaluate the neuroimaging findings and long-term neurodevelopmental outcomes of fetuses and children following intrauterine blood transfusion (IUT) for parvo B19 infection-induced anemia compared to those with RBC alloimmunization.

METHODS

We conducted a retrospective cohort study including women who underwent an IUT due to fetal anemia between 2006 and 2019 in a tertiary, university-affiliated medical center. The cohort was divided into two groups: a study group - fetuses affected by congenital parvo B19 infection; and a control group - fetuses affected by RBC alloimmunization. Retrospective data such as antenatal sonographic evaluations, fetal brain MRI results, and short-term fetal and neonatal outcomes were collected. All children underwent a neurodevelopmental evaluation after birth using a Vineland questionnaire. Primary outcome was defined as the presence or absence of neurodevelopmental delay. Secondary outcome was defined as the presence of abnormal fetal neuroimaging findings such as cerebellar hypoplasia, polymicrogyria, intracranial hemorrhage, or severe ventriculomegaly.

RESULTS

Overall, 71 fetuses requiring at least one IUT were included in the study. Of these, 18 were affected by parvo B19 infection and 53 by RBC alloimmunization with various associated antibodies. Fetuses in the parvo B19 group presented at an earlier gestational age (22.91 ± 3.36 weeks vs. 27.37 ± 4.67 weeks, p = 0.002) and were more affected by hydrops (93.33% vs. 16.98%, p < 0.001). Three fetuses out of the 18 (16.67%) fetuses in the parvo B19 group died in utero following the IUT. Abnormal neuroimaging findings were detected in 4/15 (26.7%) of the parvo B19 survivors versus 2/53 (3.8%) of fetuses affected by RBC alloimmunization (p = 0.005). There was no difference in long-term neurodevelopmental delay rates between the children in the study and control groups, as assessed at the average age of 3.65 and 6.53 years, accordingly.

CONCLUSION

Fetal anemia due to parvo B19, treated with IUT, might be associated with increased rates of abnormal neurosonographic findings. The correlation between those findings and long-term adverse neurodevelopmental outcomes requires further investigation.

Prevalence of anti-parvovirus B19 IgG and IgM and parvovirus B19 viremia in pregnant women in an urban area of Northern Italy

Parvovirus B19 (B19V) infection in pregnancy is mostly asymptomatic, but can cause complications including abortion and fetal hydrops. Although its infection is ubiquitous, seroprevalence among pregnant women varies according to different geographical areas. Since seroprevalence data in Italy are limited, the prevalence of antibodies and DNA in pregnant women was evaluated retrospectively, correlating the clinical situation of mothers and newborns. One thousand eight hundred and ninety-three sequential sera were examined from pregnant women (60.8% in the first trimester, 16.6% in the second one, and 22.6% in the third one, respectively) for anti-B19V IgG and IgM (confirmed by immunoblot); 1402 (74.1%) were of Italian origin and 491 (25.9%) non-Italian women. Molecular tests were used to search for viral genome. One thousand three hundred and fifteen (69.5%) samples were IgG-positive, 21 (1.1%) IgM-positive, and 578 (30.5%) nonimmune. The difference in IgG seroprevalence between Italian (71.1%) and non-Italian women (64.8%) was statistically significant. Of the 21 IgM-positive women, 16 were confirmed positive also by immunoblot (prevalence: 0.8%), of which 11 were viraemic (prevalence: 0.6%; mean 1.3 × 10⁴  geq/ml). Mothers were asymptomatic, and the newborns had no clinical signs of congenital infection. IgG seroprevalence in Italy is high, with differences between Italian women and non-Italian women from geographic areas with lower endemic levels of B19V. The consistent migratory flows in place could lead to an increase in the number of susceptible women. The prevalence of viremia is low, and has not been associated with evident fetal damage at birth.

Human parvovirus B19 infection in a pregnant patient resulting in severe hydrops, foetal death and persistent infection

Human parvovirus B19 (B19V) is the aetiological agent of erythema infectiosum. Primary infection during pregnancy can be transmitted to the foetus and cause foetal abnormalities related to depletion of erythrocyte progenitor cells, including congenital anaemia, hydrops, and foetal death. In this paper we report the detection of B19V infection in a pregnant patient, which onset occurred without appreciable signs and symptoms until she developed inappropriate contractions for gestational age and fluid loss. B19V infection resulted in severe hydrops fetalis with a fatal course for the foetus, while persisted in the mother at least 12 months after foetal death. The objective of this report is to highlight the importance of optimizing B19V diagnosis through early suspicion and testing during pregnancy. Knowing the mother’s immune status before or at the beginning of gestation can contribute, together with early diagnosis, to improve the management of patients at risk.

Intrauterine transfusion in 103 fetuses with severe anemia caused by parvovirus infection. A multicenter retrospective study

PURPOSE

Evaluating procedure-related complications and perinatal outcomes after intrauterine transfusion (IUT) before or after 20⁺⁰ weeks of gestation in fetuses with severe anemia due to intrauterine human parvovirus B19 infection.

METHODS

A retrospective study investigating fetuses requiring IUT for fetal Parvo B19 infection in two tertiary referral centers between December 2002 and December 2021. Procedure-related complications, intrauterine fetal death (IUFD), and perinatal outcome were correlated to gestational age (GA) at first IUT, the presence of hydrops and fetal blood sampling results.

RESULTS

A total of 186 IUTs were performed in 103 fetuses. The median GA at first IUT was 19⁺³ (13⁺⁰-31⁺⁴) weeks of gestation. IUFD occurred in 16/103 fetuses (15.5%). Overall survival was 84.5% (87/103). Hydrops (p = 0.001), lower mean hemoglobin at first IUT (p = 0.001) and low platelets (p = 0.002) were strongly associated with IUFD. There was no difference observed in fetuses transfused before or after 20⁺⁰ weeks of gestation.

CONCLUSION

IUT is a successful treatment option in fetuses affected by severe anemia due to parvovirus B19 infection in specialized centers. In experienced hands, IUT before 20 weeks is not related to worse perinatal outcome.

Parvovirus B19 infection during pregnancy

Parvovirus B19 (B19V) is a widespread pathogen causing infection that occurs mostly in children. Even though infection of B19V is mainly asymptomatic, it can bring about a few conditions that may require medical intervention, including erythema infectiosum (fifth disease), slapped cheek syndrome, papular-purpuric gloves and socks syndrome (PPGSS), as well as other disorders related to the hematological system. Despite the fact that the most common route of transmission is through the respiratory system, B19V can be also transmitted transplacentally from mother to foetus. Vertical transmission may lead to myocarditis, thrombocytopenia, neural manifestations, and foetal hydrops, which may be life-threatening conditions to both mother and foetus. Detection of B19V infection is based mostly on molecular and serological screening and it is performed after suspected exposure to pathogen or exhibition of symptoms. Currently, there is no specific medication against B19V infection, therefore, treatment is based on the elimination of symptoms. New therapies are, however, under development.

Environmental Monitoring of Parvovirus B19 in the Kidney Transplantation Ward of a Chinese Teaching Hospital

Purpose

Parvovirus B19 (B19V) infection is a viral threat after kidney transplantation. It is mainly transmitted by close-contact inhalation of aerosolized viral particles. The risk of nosocomial spread of B19V in the transplantation ward is quite high. This study aimed to evaluate the quality of routine disinfection and the effectiveness of isolation measures in the wards of B19V-infected kidney transplant recipients.

Patients and Methods

Throat swab samples of 19 kidney transplant recipients admitted to the isolation ward and three healthcare workers (HCWs) were collected for viral DNA detection. Routine disinfection procedures were performed twice a day in general and B19V isolation wards. Environmental surface and air samples were collected for viral DNA detection before and after disinfection.

Results

A total of four patients were diagnosed with B19V infection and transferred to the B19V isolation ward, of which only two had positive throat swab samples. The other 15 patients and all HCWs tested negative for B19V. A total of 88 environmental surface and air samples were collected. Eight of the environmental samples collected in the B19V isolation ward before disinfection tested positive for B19V, while one sample tested positive after disinfection. In the general wards, all environmental samples collected before disinfection tested negative for B19V. All 24 samples collected from ambient air, whether in B19V isolation or general wards, before or after disinfection, tested negative for B19V.

Conclusion

Existing methods of routine or terminal disinfection for air and object surfaces were effective in eliminating B19V from object surfaces and ambient air in the isolation and general wards. Material surfaces that are exposed to high frequency and easily contaminated by blood, body fluids, and indoor air were the focus of cleaning and disinfection. Nosocomial cross-infection of other immunocompromised patients and HCWs can be avoided if appropriate prevention and control measures are taken.

Clinically relevant DNA viruses in pregnancy

Infections by DNA viruses during pregnancy are associated with increased health risks to both mother and fetus. Although not all DNA viruses are related to an increased risk of complications during pregnancy, several can directly infect the fetus and/or cause placental dysfunction. During NIPT analysis, the presence of viral DNA can be detected, theoretically allowing screening early in pregnancy. Although treatment options are currently limited, this might rapidly change in the near future. It is therefore important to be aware of the potential impact of these viruses on feto-maternal health. In this manuscript we provide a brief introduction into the most commonly detected DNA viruses in human cell-free DNA sequencing experiments and their pathogenic potential during pregnancy. This article is protected by copyright. All rights reserved.

Parvovirus b19 infection in pregnancy - A review

Parvovirus B19 (B19V) is a widespread infection that may affect 1-5% of pregnant women, mainly with normal pregnancy outcome. Vertical transmission occurs in 33-51% of cases of maternal infection. B19V infection is an important cause of fetal morbidity (fetal anaemia and non-immune hydrops) and mortality, predominantly in the second trimester. Diagnosis of B19V infection requires a multi-method approach using mainly serology and PCR techniques. Severe fetal anaemia is managed with intrauterine transfusion with perinatal survival rates following intrauterine transfusion ranging from 67% to 85%. If fetal anaemia is mild, and considering that hydrops can spontaneously resolve, invasive therapy is not recommended and B19V complicated pregnancy may be non-invasively monitored by serial ultrasound examination and MCV-PSV measurements. As an alternative, intrauterine IVIG therapy has been described with successful treatment of fetal hydrops. No specific antiviral therapy or vaccine is presently available for B19V infection but efforts in the search for compounds inhibiting B19V replication are now being pursued. New virus-like-particle based parvovirus B19 vaccine candidates, produced by co-expressing VP2 and either wild-type VP1 or phospholipase-negative VP1 in a regulated ratio from a single plasmid inSaccharomyces cerevisiae have been developed and show sufficient promise to test in humans.

Human parvovirus B19: a review of clinical and epidemiological aspects in Brazil

Since the first evidence of human parvovirus B19 (B19V) infection in late 80s, several studies have been conducted to clarify the spectrum of clinical diseases in Brazil. B19V infection is prevalent in the general population and has exhibited a cyclical pattern of occurrence every 4-5 years, with the predominance of genotype 1 over 3b. During epidemic periods the wide range of clinical conditions, such as ertythema infectiosum, arthropathy, transient aplastic crisis, nonimmune hydrops fetalis and B19V-hepatitis were diagnosed. However, many infections are likely asymptomatic or have a self-limiting clinical course and are not readly diagnosed. Besides, the similarity of the symptoms of ertythema infectiosum to other rash diseases and the broadly circulation of arboviruses makes differential diagnosis more difficult. In this article, we provide a historical comprehensive overview of the research on parvovirus B19 conducted in Brazil, with a focus on the clinical and epidemiological aspects of the infection.

Identification and management of congenital parvovirus B19 infection

Parvovirus B19 (B19V) infection is well known for its mild, self-limiting clinical presentations in children, such as erythema infectiosum. Approximately 40% of women of childbearing age are susceptible to B19V infection. While maternal B19V infection usually has a good prognosis, B19V can cause severe fetal anaemia and pregnancy loss due to its ability to suppress erythroid progenitor cells. Non-invasive ultrasound monitoring for fetal anaemia is usually performed if maternal seroconversion occurs in the first 20 weeks of gestation, with amniocentesis for fetal infection reserved for those who first present with fetal anaemia or hydrops of unknown cause. Intrauterine transfusion is the standard treatment for severe fetal anaemia and is associated with a significant improvement in survival. However, survivors of hydrops fetalis may have a higher rate of long-term neurodevelopmental complications compared with non-hydropic survivors. This review aims to synthesise published data on the diagnosis, surveillance and outcomes of congenital parvovirus infection to assist clinicians in diagnosing and managing this important condition.

CNS Macrophages and Infant Infections

The central nervous system (CNS) harbors its own immune system composed of microglia in the parenchyma and CNS-associated macrophages (CAMs) in the perivascular space, leptomeninges, dura mater, and choroid plexus. Recent advances in understanding the CNS resident immune cells gave new insights into development, maturation and function of its immune guard. Microglia and CAMs undergo essential steps of differentiation and maturation triggered by environmental factors as well as intrinsic transcriptional programs throughout embryonic and postnatal development. These shaping steps allow the macrophages to adapt to their specific physiological function as first line of defense of the CNS and its interfaces. During infancy, the CNS might be targeted by a plethora of different pathogens which can cause severe tissue damage with potentially long reaching defects. Therefore, an efficient immune response of infant CNS macrophages is required even at these early stages to clear the infections but may also lead to detrimental consequences for the developing CNS. Here, we highlight the recent knowledge of the infant CNS immune system during embryonic and postnatal infections and the consequences for the developing CNS.

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.

Performance of Zika Assays in the Context of Toxoplasma gondii, Parvovirus B19, Rubella Virus, and Cytomegalovirus (TORCH) Diagnostic Assays

Infections during pregnancy that may cause congenital abnormalities have been recognized for decades, but their diagnosis is challenging. This was again illustrated with the emergence of Zika virus (ZIKV), highlighting the inherent difficulties in estimating the extent of pre- and postnatal ZIKV complications because of the difficulties in establishing definitive diagnoses. We reviewed the epidemiology, infection kinetics, and diagnostic methods used for Toxoplasma gondii, parvovirus B19, rubella virus, and cytomegalovirus (TORCH) infections and compared the results with current knowledge of ZIKV diagnostic assays to provide a basis for the inclusion of ZIKV in the TORCH complex evaluations. Similarities between TORCH pathogens and ZIKV support inclusion of ZIKV as an emerging TORCH infection. Our review evaluates the diagnostic performance of various TORCH diagnostic assays for maternal screening, fetal screening, and neonatal screening. We show that the sensitivity, specificity, and positive and negative predictive value of TORCH complex pathogens are widely variable, stressing the importance of confirmatory testing and the need for novel techniques for earlier and accurate diagnosis of maternal and congenital infections. In this context it is also important to acknowledge different needs and access to care for different geographic and resource settings.

No. 363-Investigation and Management of Non-immune Fetal Hydrops

OBJECTIVE

To describe the current investigation and management of non-immune fetal hydrops with a focus on treatable or recurring etiologies.

OUTCOMES

To provide better counselling and management in cases of prenatally diagnosed non-immune hydrops.

EVIDENCE

Published literature was retrieved through searches of PubMed or MEDLINE, CINAHL, and The Cochrane Library in 2017 using key words (non-immune hydrops fetalis, fetal hydrops, fetal therapy, fetal metabolism). Results were restricted to systematic reviews, randomized controlled trials/controlled clinical trials, observational studies, and significant case reports. Additional publications were identified from the bibliographies of these articles. There were no date or language restrictions. Searches were updated on a regular basis and incorporated in the guideline to September 2017. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinicalpractice guideline collections, clinical trial registries, and national and international medical specialty societies.

BENEFITS, HARMS, AND COSTS

These guidelines educate readers about the causes of non-immune fetal hydrops and its prenatal counselling and management. It also provides a standardized approach to non-immune fetal hydrops, emphasizing the search for prenatally treatable conditions and recurrent genetic etiologies.

VALUES

The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care.

RECOMMENDATIONS

The risk of maternal parvovirus B19 infection during pregnancy on fetal loss and fetal hydrops: A systematic review and meta-analysis

BACKGROUND

Human parvovirus B19 (B19) is widespread infection in humans, yet the impact on adverse pregnancy outcomes is controversial.

OBJECTIVE

to evaluate the impact of B19 infection during pregnancy on adverse pregnancy outcome, and investigated the incidence of fetal loss and fetal hydrops after maternal B19 infection during pregnancy.

STUDY DESIGN

A systematic literature search was performed using Embase, Medline, PubMed, Web of science, and the Cochrane Library database for relevant publications up to 10^th August 2018. Cohort studies and case-control studies were included in analyses.

RESULTS

In total, 36 eligible studies were included. Of these, 18 studies reported the risk of maternal B19 infection during pregnancy on fetal loss and 20 studies reported the incidence of fetal loss or fetal hydrops after maternal B19 infection. Collectively, the results indicated that maternal B19 infection increased the risk of fetal loss, spontaneous abortion, and stillbirth with ORs of 2.68 (95% CI: 2.02-3.55), 2.42 (95% CI: 1.76-3.33), and 3.53 (95% CI: 1.91-6.54), respectively, when compared with uninfected pregnant women. In addition, the incidence of fetal loss and fetal hydrops in B19 infected pregnant women was 7.6% (95% CI: 5.5-9.5) and 9.3% (95% CI: 5.6-13.0), respectively.

CONCLUSIONS

maternal parvovirus B19 infection during pregnancy increased the risk of fetal loss, spontaneous abortion, and stillbirth. A high incidence of fetal loss and fetal hydrops was observed in pregnant women with parvovirus B19 infection.

Primary Prenatal Care: Screening, Prevention, and Treatment of Viral Infections

Prenatal care providers are responsible for a basic understanding of the viral contagions that place women and fetal well-being at risk during pregnancy. This article reviews the evidence-based routine prenatal screening guidelines for previously unrecognized maternal infection, counseling toward risk reduction, recommended maternal immunizations, and the management of maternal and fetal complications of some viral exposures and infections.

Outcome of fetuses with congenital parvovirus B19 infection: systematic review and meta-analysis

OBJECTIVE

To explore the outcome of fetuses affected by congenital parvovirus B19 (PB19) infection, with or without signs of hydrops on ultrasound.

METHODS

PubMed, EMBASE and CINAHL databases were searched for studies reporting on prenatal diagnosis and outcome of fetal PB19 infection. The outcomes explored were miscarriage, perinatal death (PND), intrauterine death, neonatal death, spontaneous resolution of hydrops or fetal anemia, need for intrauterine transfusion (IUT), resolution of hydrops or anemia after transfusion, fetal loss following transfusion, abnormal brain scan after birth and abnormal neurodevelopmental outcome. Outcomes were reported according to the presence or absence of signs of hydrops on ultrasound. A subgroup analysis was performed including hydropic and non-hydropic fetuses diagnosed at < 20 weeks and ≥ 20 weeks of gestation. Meta-analyses of proportions and meta-analyses using individual-data random-effects logistic regression were performed to analyze the data.

RESULTS

Thirty-five observational studies were included, involving 611 fetuses affected by PB19 infection. The risks of miscarriage (odds ratio (OR), 11.5; 95% CI, 2.7-49.7) and PND (OR, 4.2; 95% CI, 1.6-11.0) were higher in fetuses with PB19 infection presenting, compared with those not presenting, signs of hydrops on ultrasound. In fetuses affected by hydrops, spontaneous resolution of the infection, defined as disappearance of hydrops without need for IUT, occurred in 5.2% (95% CI, 2.5-8.8%) of cases whereas, in the group of fetuses not affected by hydrops, infection resolved in 49.6% (95% CI, 20.7-78.6%) of cases. IUT was performed in 78.7% (95% CI, 66.4-88.8%) of hydropic and in 29.6% (95% CI, 6.0-61.6%) of non-hydropic fetuses affected by congenital PB19 infection and resolution of the infection after IUT occurred in 55.1% (95% CI, 34.0-75.3%) and in 100% (95% CI, 57.3-100%) of cases, respectively. The risk of fetal loss after IUT was higher in fetuses affected compared with those not affected by hydrops (OR, 9.8; 95% CI, 2.8-34.6). The prevalence of abnormal brain imaging was 9.8% (95% CI, 2.5-21.0%) in fetuses affected and 0.0% (95% CI, 0.0-7.0%) in those not affected by hydrops, whilst the corresponding figures for abnormal neurodevelopmental outcome were 9.5% (95% CI, 2.6-20.2) and 0.0% (95% CI, 0.0-7.5), respectively; however, statistical power to assess these outcomes was inadequate due to the small number of included cases.

CONCLUSIONS

Hydrops is the main determinant of mortality and adverse perinatal outcome in fetuses with PB19 infection. Perinatal outcome in non-hydropic fetuses is generally favorable. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

N° 363 - Évaluation et prise en charge de l'anasarque fœtoplacentaire non immune

OBJECTIF

Décrire les méthodes actuelles d'évaluation et de prise en charge de l'anasarque fœtoplacentaire non immune en mettant l'accent sur les étiologies traitables ou récurrentes. RéSULTATS: Offrir de meilleurs services de conseil et de prise en charge en cas d'anasarque fœtoplacentaire non immune diagnostiquée en période prénatale. DONNéES: La littérature publiée a été récupérée au moyen de recherches menées dans PubMed, MEDLINE, CINAHL, et la Bibliothèque Cochrane en 2017 à l'aide de mots-clés (« non-immune hydrops fetalis », « fetal hydrops », « fetal therapy », « fetal metabolism »). Les articles retenus portaient sur des revues systématiques, des essais cliniques contrôlés, randomisés ou non, des études observationnelles et des études de cas importantes. D'autres publications ont été repérées dans les bibliographies de ces articles. Aucune restriction de date ou de langue n'a été employée. Les recherches ont été mis à jour régulièrement, et les résultats ont été incorporés à la directive clinique jusqu'en septembre 2017. Nous avons également tenu compte de la littérature grise (non publiée) trouvée sur les sites Web d'organismes d'évaluation des technologies de la santé et d'autres organismes liés aux technologies de la santé, dans des collections de directives cliniques et des registres d'essais cliniques, et obtenue auprès d'associations nationales et internationales de médecins spécialistes. AVANTAGES, INCONVéNIENTS ET COûTS: La présente directive clinique renseigne les lecteurs sur les causes de l'anasarque fœtoplacentaire non immune ainsi que sur son évaluation et sa prise en charge. Elle propose également une approche standardisée d'évaluation et de prise en charge, et met l'accent sur la recherche des conditions traitables en période prénatale et des étiologies génétiques récurrentes.

VALEURS

La qualité des données probantes a été évaluée en fonction des critères décrits dans le rapport du Groupe d'étude canadien sur les soins de santé préventifs. RECOMMANDATIONS.

Infection status of human parvovirus B19, cytomegalovirus and herpes simplex Virus-1/2 in women with first-trimester spontaneous abortions in Chongqing, China

BACKGROUND

Infection with Parvovirus B19 (B19V), Cytomegalovirus (CMV) and Herpes Simplex Virus-1/2 (HSV-1/2) may cause fetal loses including spontaneous abortion, intrauterine fetal death and non-immune hydrops fetalis. Few comprehensive studies have investigated first-trimester spontaneous abortions caused by virus infections in Chongqing, China. Our study intends to investigate the infection of B19V, CMV and HSV-1/2 in first-trimester spontaneous abortions and the corresponding immune response.

METHODS

100 abortion patients aged from 17 to 47 years were included in our study. The plasma samples (100) were analyzed qualitatively for specific IgG/IgM for B19V, CMV and HSV-1/2 (Virion\Serion, Germany) according to the manufacturer's recommendations. B19V, CMV and HSV-1/2 DNA were quantification by Real-Time PCR.

RESULTS

No specimens were positive for B19V, CMV, and HSV-1/2 DNA. By serology, 30.0%, 95.0%, 92.0% of patients were positive for B19V, CMV and HSV-1/2 IgG respectively, while 2% and 1% for B19V and HSV-1/2 IgM.

CONCLUSION

The low rate of virus DNA and a high proportion of CMV and HSV-1/2 IgG for most major of abortion patients in this study suggest that B19V, CMV and HSV-1/2 may not be the common factor leading to the spontaneous abortion of early pregnancy.

Parvovirus B19 infection in pregnancy-awareness and opportunities

Parvovirus B19 (B19V) is a human pathogenic virus associated with a wide range of clinical conditions. In pregnancy, B19V poses a potential hazard to the fetus as crossing the placental barrier and infecting erythroid progenitor cells in bone marrow and liver, it blocks fetal erythropoiesis leading to profound anemia, hydrops and/or fetal death. The virus is not regarded as a teratogen, however more scientific awareness is emerging on mechanisms and consequences of intrauterine infection and possible sequelae in the neonatal development. Reliable diagnostic procedures and fetal management strategies, including intrauterine transfusion, are established. In spite of being a recognized fetotropic agent possibly leading to fetal loss, testing for B19V is not routinely included in preconception or antenatal screenings, possibly delaying the management of B19V-complicated pregnancies. Continuous advances in B19V research will provide for better diagnostic methods and algorithms, as well as for the development of effective prophylactic interventions and novel therapeutic options.

Association between Zika virus and microcephaly in French Polynesia, 2013-15: a retrospective study

BACKGROUND

The emergence of Zika virus in the Americas has coincided with increased reports of babies born with microcephaly. On Feb 1, 2016, WHO declared the suspected link between Zika virus and microcephaly to be a Public Health Emergency of International Concern. This association, however, has not been precisely quantified.

METHODS

We retrospectively analysed data from a Zika virus outbreak in French Polynesia, which was the largest documented outbreak before that in the Americas. We used serological and surveillance data to estimate the probability of infection with Zika virus for each week of the epidemic and searched medical records to identify all cases of microcephaly from September, 2013, to July, 2015. Simple models were used to assess periods of risk in pregnancy when Zika virus might increase the risk of microcephaly and estimate the associated risk.

FINDINGS

The Zika virus outbreak began in October, 2013, and ended in April, 2014, and 66% (95% CI 62-70) of the general population were infected. Of the eight microcephaly cases identified during the 23-month study period, seven (88%) occurred in the 4-month period March 1 to July 10, 2014. The timing of these cases was best explained by a period of risk in the first trimester of pregnancy. In this model, the baseline prevalence of microcephaly was two cases (95% CI 0-8) per 10,000 neonates, and the risk of microcephaly associated with Zika virus infection was 95 cases (34-191) per 10,000 women infected in the first trimester. We could not rule out an increased risk of microcephaly from infection in other trimesters, but models that excluded the first trimester were not supported by the data.

INTERPRETATION

Our findings provide a quantitative estimate of the risk of microcephaly in fetuses and neonates whose mothers are infected with Zika virus.

FUNDING

Labex-IBEID, NIH-MIDAS, AXA Research fund, EU-PREDEMICS.

Blood Groups in Infection and Host Susceptibility

Blood group antigens represent polymorphic traits inherited among individuals and populations. At present, there are 34 recognized human blood groups and hundreds of individual blood group antigens and alleles. Differences in blood group antigen expression can increase or decrease host susceptibility to many infections. Blood groups can play a direct role in infection by serving as receptors and/or coreceptors for microorganisms, parasites, and viruses. In addition, many blood group antigens facilitate intracellular uptake, signal transduction, or adhesion through the organization of membrane microdomains. Several blood groups can modify the innate immune response to infection. Several distinct phenotypes associated with increased host resistance to malaria are overrepresented in populations living in areas where malaria is endemic, as a result of evolutionary pressures. Microorganisms can also stimulate antibodies against blood group antigens, including ABO, T, and Kell. Finally, there is a symbiotic relationship between blood group expression and maturation of the gastrointestinal microbiome.

Parvovirus B19V infection in Israel: prevalence and occurrence of acute infection between 2008 and 2013

Differences in the seroprevalence and unique pattern of parvovirus B19 (B19V) acute infections have been documented around the world. This study was conducted to estimate the seroprevalence of anti-parvovirus B19V IgG antibodies in the Israeli population and to assess the pattern of acute infection based on data from two laboratories in Israel. The overall IgG prevalence in the 1008 representative sera samples was 61·4% and the age-adjusted prevalence rate was 58·2%. Seropositivity was significantly associated with age, ranging from 25·7% in children aged <10 years to 70% in people aged >20 years. While no significant differences in seropositivity were detected between sexes and population groups, significantly lower seroprevalence was observed in older Jews born in Africa or Asia. Acute infection rates of 4·1% (234 cases) were found based on the positive IgM results identified in samples from 5663 individuals collected between 2008 and 2013. Annual peaks of infection were observed in 2008 and 2011–2012 and major seasonal peak of B19V IgM positivity was identified in June each year. The number of requests for B19V serology was significantly higher for women aged 20–39 years while the majority IgM-positive cases were identified in young children. With more than 30% of the adult population being susceptible to B19V infection, monitoring B19V status should be considered in specific risk groups such as pregnant women.

TORCH infections

TORCH infections classically comprise toxoplasmosis, Treponema pallidum, rubella, cytomegalovirus, herpesvirus, hepatitis viruses, human immunodeficiency virus, and other infections, such as varicella, parvovirus B19, and enteroviruses. The epidemiology of these infections varies; in low-income and middle-income countries, TORCH infections are major contributors to prenatal, perinatal, and postnatal morbidity and mortality. Evidence of infection may be seen at birth, in infancy, or years later. For many of these pathogens, treatment or prevention strategies are available. Early recognition, including prenatal screening, is key. This article covers toxoplasmosis, parvovirus B19, syphilis, rubella, hepatitis B virus, hepatitis C virus, and human immunodeficiency virus.

Fetal Intracardiac Transfusions in Hydropic Fetuses with Severe Anemia

Introduction: Fetal anemia can have significant perinatal morbidity and mortality, particularly with onset prior to 20 weeks of gestation. Materials and Methods: We detail a case-cohort study (n = 8) of all women who underwent fetal in-utero, intracardiac transfusion prior to 24 weeks of gestation (7 women before 20 + 1 weeks), between March 2004 and September 2014, in a supraregional Fetal Medicine Center in the United Kingdom, comprising 2.2% of all transfusions performed during this period. All the fetuses were hydropic, with high maternal BMI, and had severe anemia as an indicator for transfusion. It was an attempt to perform intravascular transfusion when other common routes of fetal vascular access had failed. Results: There were 2 intrauterine deaths (25%), both of which were associated with in-utero transfusion and fulminant parvovirus B19 infection. The perinatal survival rate was 75% (6/8). Discussion: Fetal in-utero, intravascular transfusion by the intracardiac route may be used to correct severe early-onset anemia. It is particularly useful when technical issues of fetal size, early gestation (<20 weeks), maternal adiposity, and hydrops fetalis make umbilical cord or intrahepatic vein puncture technically difficult. Survival rates appear comparable to other series of pregnancies where in-utero transfusion is performed at early gestation.

Clinical features of 10 fetuses with prenatally diagnosed parvovirus b19 infection and fetal hydrops

OBJECTIVES

To evaluate the clinical features of fetuses with prenatally diagnosed parvovirus B19 infection and fetal hydrops.

METHODS

Parvovirus infection was diagnosed by PCR analysis of amniotic fluid or fetal blood. Fetal anemia was assessed by Doppler measurements of the middle cerebral artery peak systolic velocity (MCA-PSV) and confirmed by fetal blood. Intrauterine transfusions (IUT) were performed only if the MCA-PSV was > 1.5°MoM.

RESULTS

In our study population 10 cases of parvovirus infection which were associated with fetal hydrops were reviewed. The median gestational age at diagnosis was 21 (16.3-24.2) weeks. Five of our cases received IUT and four fetuses survived. The remaining five cases were managed conservatively and two fetuses survived.

CONCLUSIONS

The survival rate for parvovirus infection associated with fetal hydrops was 60%. MCA-PSV and IUT are useful for the management and treatment of fetal anemia due to parvovirus infection.

The seroprevalence of parvovirus B19 infection in pregnant women in Sudan

Parvovirus B19 (B19V) infection during pregnancy may have serious consequences like fetal anaemia, hydrops fetalis, and fetal loss. Since epidemiological data on B19V infection are generally lacking in Sudan, the current study aimed to determine the seroprevalence of B19V in Sudanese pregnant women. Five hundred women, attending antenatal clinics in Khartoum state between November 2008 and March 2009, were enrolled and screened for B19V IgG and IgM antibodies by enzyme immunoassays. The study revealed a B19V IgG seroprevalence of 61·4%, with one subject positive for IgM. B19V DNA was not detected by PCR in any of the tested individuals. B19V IgG seroprevalence was significantly correlated with multigravidity (P = 0·046). Our data showed that B19V infection is prevalent in Sudan and we recommend further studies in Sudanese women, particularly in those with complications and adverse outcomes of pregnancy.

Successful immunotherapy in life-threatening parvovirus B19 infection in a child

We report a case of an immunocompetent child who developed parvovirus B19 infection complicated by autoinflammatory disease with myocarditis, tamponade and macrophage activation syndrome. He recovered with immunotherapy including prednisone, immunoglobulins, cyclosporin and anakinra (anti-interleukin-1). The report shows that parvovirus can provoke severe systemic inflammation with acute heart injury and that anti-interleukin-1 might be considered in such parvovirus-related inflammation.

Evidence for the transmission of parvovirus B19 in patients with bleeding disorders treated with plasma-derived factor concentrates in the era of nucleic acid test screening

BACKGROUND

Parvovirus B19 (B19V) is a small, nonenveloped virus that typically causes a benign flu-like illness that occurs most frequently in childhood. The virus is resistant to current viral inactivation steps used in the manufacture of antihemophilic factor concentrates and B19V transmission through these products has been documented. Since 2000, B19V nucleic acid test (NAT) screening of plasma pools has been implemented to further decrease the viral burden in these products, but no study has examined populations using these products to assess the impact of the screening on B19V transmission.

STUDY DESIGN AND METHODS

Blood specimens obtained from participants of a surveillance system established in federally supported specialized bleeding disorders clinics were used in a B19V seroprevalence study.

RESULTS

A total of 1643 specimens from 1043 participants age 2 to 7 years born after B19V NAT screening was implemented were tested. Age-specific prevalence rates were generally higher for subjects exposed to either plasma-derived products alone or in combination with other products compared to subjects with no exposure to antihemophilic products. Overall, compared to participants unexposed to blood or blood products, those exposed to plasma-derived products alone were 1.7 times more likely to have antibodies to B19V (p = 0.002).

CONCLUSION

These results are consistent with continued B19V transmission through plasma-derived factor concentrates. Effective viral inactivation and detection processes are needed to protect users of these products from infection with B19V or other new or emerging viruses.

Parvovirus B19 Achievements and Challenges

Parvovirus B19 is a widespread human pathogenic virus, member of the Erythrovirus genus in the Parvoviridae family. Infection can be associated with an ample range of pathologies and clinical manifestations, whose characteristics and outcomes depend on the interplay between the pathogenetic potential of the virus, its adaptation to different cellular environments, and the physiological and immune status of the infected individuals. The scope of this review is the advances in knowledge on the biological characteristics of the virus and of virus-host relationships; in particular, the interactions of the virus with different cellular environments in terms of tropism and ability to achieve a productive replicative cycle, or, on the contrary, to establish persistence; the consequences of infection in terms of interference with the cell physiology; the process of recognition of the virus by the innate or adaptive immune system, hence the role of the immune system in controlling the infection or in the development of clinical manifestations. Linked to these issues is the continuous effort to develop better diagnostic algorithms and methods and the need for development of prophylactic and therapeutic options for B19V infections.

Gynecologic and other infections in pregnancy

The treatment of gynecologic and other infections in obstetric patients involves consideration of the physiologic changes of pregnancy, the clinical implications of the infection for the patient as well as the fetus, and the safety of antimicrobials available for therapy. This article highlights the treatment of infections of the vagina, uterus, and urinary tract, with a focus on how therapy changes in obstetric patients. In addition, the emergency department management of other clinically important infections in pregnancy, such as those caused by the human immunodeficiency virus, influenza viruses, methicillin-resistant Staphylococcus aureus, Parvovirus, Listeria, and others is reviewed.

Polymicrogyria in a fetus with human parvovirus B19 infection: a case with radiologic-pathologic correlation

We report the prenatal magnetic resonance imaging (MRI) appearance of polymicrogyria with pathologic correlation in a fetus with congenital parvovirus B19 infection. Prenatal ultrasound revealed non-immune hydrops, but detected no fetal brain abnormalities. A subsequent fetal MRI scan performed at 23 weeks' gestation demonstrated bilateral polymicrogyria, which was confirmed at autopsy. To our knowledge, prenatal diagnosis of polymicrogyria in association with congenital parvovirus B19 infection has not been previously described. This case provides further evidence for brain abnormalities resulting from congenital parvovirus B19 infection, and suggests that fetal neuroimaging with MRI would be of value in suspected cases of congenital parvovirus infection.

Maternal IgM antibody status in confirmed fetal cytomegalovirus infection detected by sonographic signs

OBJECTIVE

To evaluate the value of maternal IgM to cytomegalovirus (CMV) as a predictive factor of fetal infection in fetuses with sonographic markers.

METHODS

Observational study (2006-2011) including a consecutive series of 19 fetuses with sonographic markers of fetal infection and confirmed infection by positive CMV-DNA in amniotic fluid or fetal blood. We evaluated the status of maternal CMV IgM at the time of sonographic suspicion.

RESULTS

During this 6-year study period, CMV infection was diagnosed in 19 fetuses from 18 pregnancies, including 16 singletons, both twins of a monochorionic diamniotic pregnancy and one twin of a dichorionic pregnancy. Sonographic suspicion was established on the basis of one or more of the following: brain abnormalities (14), fetal hydrops (4), hyperechogenic bowel (4), pericardial effusion (1), cardiomegaly (1), oligoanhydramnios (4), and placentomegaly (2). Maternal IgG antibodies were positive in all cases but maternal IgM antibodies were negative in 56% of pregnancies. Five of the 10 pregnancies with negative maternal IgM were diagnosed in the second trimester and five in the third trimester.

CONCLUSION

In around half of fetuses with confirmed CMV infection ascertained by sonographic markers, maternal IgM antibodies are negative and should therefore not be used as a diagnostic parameter.