Congenital enterovirus 71 infection: a case study with virology and immunohistochemistry

Recent advances in enterovirus A71 pathogenesis: a focus on fatal human enterovirus A71 infection

Enterovirus A71 (EV-A71) is one of the major pathogens responsible for hand, foot, and mouth disease (HFMD). Many HFMD outbreaks have been reported throughout the world in the past decades. Compared with other viruses, EV-A71 infection is more frequently associated with severe neurological complications and even death in children. EV-A71 can also infect adults and cause severe complications and death, although such cases are very uncommon. Although fatal cases of EV-A71 infection have been reported, the underlying mechanisms of EV-A71 infection, especially the mode of viral spread into the central nervous system (CNS) and mechanisms of pulmonary edema, which is considered to be the direct cause of death, have not yet been fully clarified, and more studies are needed. Here, we first summarize the pathological findings in various systems of patients with fatal EV-A71 infections, focussing in detail on gross changes, histopathological examination, tissue distribution of viral antigens and nucleic acids, systemic inflammatory cell infiltration, and tissue distribution of viral receptors and their co-localization with viral antigens. We then present our conclusions about viral dissemination, neuropathogenesis, and the mechanism of pulmonary edema in EV-A71 infection, based on pathological findings.

A Rare Presentation of Hand, Foot, and Mouth Disease During Pregnancy

This case report is about an 18-year-old primigravida diagnosed with hand, foot, and mouth disease (HFMD) at 34 weeks of gestation. She had classic rashes on her hands and mouth but was otherwise healthy. The baby was delivered at 39 weeks via spontaneous normal vaginal delivery and was well after delivery. We provide a brief literature review on HFMD in pregnancy and a brief discussion on complications caused by the causative organisms.

Coxsackievirus B3 Infection of Human iPSC Lines and Derived Primary Germ-Layer Cells Regarding Receptor Expression

The association of members of the enterovirus family with pregnancy complications up to miscarriages is under discussion. Here, infection of two different human induced pluripotent stem cell (iPSC) lines and iPSC-derived primary germ-layer cells with coxsackievirus B3 (CVB3) was characterized as an in vitro cell culture model for very early human development. Transcriptomic analysis of iPSC lines infected with recombinant CVB3 expressing enhanced green fluorescent protein (EGFP) revealed a reduction in the expression of pluripotency genes besides an enhancement of genes involved in RNA metabolism. The initial distribution of CVB3-EGFP-positive cells within iPSC colonies correlated with the distribution of its receptor coxsackie- and adenovirus receptor (CAR). Application of anti-CAR blocking antibodies supported the requirement of CAR, but not of the co-receptor decay-accelerating factor (DAF) for infection of iPSC lines. Among iPSC-derived germ-layer cells, mesodermal cells were especially vulnerable to CVB3-EGFP infection. Our data implicate further consideration of members of the enterovirus family in the screening program of human pregnancies. Furthermore, iPSCs with their differentiation capacity into cell populations of relevant viral target organs could offer a reliable screening approach for therapeutic intervention and for assessment of organ-specific enterovirus virulence.

Management guidelines for pregnant health care workers exposed to infectious dermatoses

Exanthematous diseases are frequently of infectious origin, posing risks, especially for pregnant health care workers (HCWs) who treat them. The shift from cell-mediated (Th1 cytokine profile) to humoral (Th2 cytokine profile) immunity during pregnancy can influence the mother’s susceptibility to infection and lead to complications for both mother and fetus. The potential for vertical transmission must be considered when evaluating the risks for pregnant HCWs treating infected patients because fetal infection can often have devastating consequences. Given the high proportion of women of childbearing age among HCWs, the pregnancy-related risks of exposure to infectious diseases are an important topic in both patient care and occupational health. Contagious patients with cutaneous manifestations often present to dermatology or pediatric clinics, where female providers are particularly prevalent; a growing number of these physicians are female. Unfortunately, the risks of infection for pregnant HCWs are not well defined. To our knowledge, there is limited guidance on safe practices for pregnant HCWs who encounter infectious dermatologic diseases. In this article, we review several infectious exanthems, their transmissibility to pregnant women, the likelihood of vertical transmission, and the potential consequences of infection for the mother and fetus. Additionally, we discuss recommendations with respect to avoidance, contact, and respiratory precautions, as well as the need for treatment after exposure.

Acarbose, as a potential drug, effectively blocked the dynamic metastasis of EV71 from the intestine to the whole body

Enterovirus 71 (EV71) is one of the main pathogens causing hand-foot-and-mouth disease (HFMD). The nose and mouth are usually the main infection entries of EV71 virus. However, its dynamic transport pathway from mouth to the whole body remains unknown. The reveal of this physiological mechanism in vivo will help to understand its transport direction, find its key proliferation nodes, and develop new preventive strategies. We trained a new strain of GFP-EV71 virus to be susceptible to mice brain by intracranial injection of mice. The adapted virus was oral-administrated to suckling mice. Then, the dynamic distributions of the virus in vivo were detected by living image system and fluorescence quantitation polymerase chain reaction (qPCR). We figured out the dynamic pathway of EV71 transport in vivo from intestine to peripheral tissue, then to the other organs. Small intestine was identified as a gateway for EV71 infection in vivo. Ileum was proved to be the main part of proliferation and transport of EV71 in small intestine of mice. EV71 was verified to enter small intestinal villus of mice through the infection of small intestinal epithelial cell. Acarbose displayed a good preventive effect on EV71 infection both in vivo and in vitro. Acarbose possibly decreased the intestinal infection of EV71 by blocking the receptor-binding sites on the surface of EV71 virion or by inhibiting various glycolic receptors on the cell surface. Thus, acarbose and its analogue may be the potential medicines to prevent EV71 infection.

Neonatal nonpolio enterovirus and parechovirus infections

Nonpolio enteroviruses and parechoviruses are frequent causes of neonatal infection. Clinical manifestations of infection range from asymptomatic infection to mild infection without sequelae to septic shock with muiltiorgan failure. Neonates with clinically apparent infection typically have mothers and/or other contacts with recent symptoms consistent with a viral illness. Severe neonatal infection with nonpolio enterovirus or parechovirus cannot be differentiated clinically from serious bacterial infection. The preferred method for diagnosing neonatal nonpolio enterovirus or parechovirus infection is PCR as it is rapid, sensitive, specific, and commercially available for the detection of virus from various clinical specimens. Investigational agents such as the capsid inhibitors pleconaril and pocapavir show promise for treatment of neonatal enterovirus infections, and other investigational agents are being developed. This review focuses on the epidemiology, diagnosis, and treatment of neonatal nonpolio enterovirus and parechovirus infections.

Cytokine and Chemokine Profiling in Patients with Hand, Foot and Mouth Disease in Singapore and Malaysia

Hand, foot and mouth disease (HFMD) is a prevalent contagious childhood disease typically associated with fever, oral lesions and limb exanthema. While HFMD is caused by a plethora of serotypes of viruses under the genus Enterovirus within the Picornaviridae family, Coxsackievirus A16 (CV-A16) and Enterovirus 71 (EV-A71) are considered the main etiological agents. In recent years however, other viruses have also been isolated in considerable numbers from infected individuals in many regions, joining the legion commonly associated with HFMD. The present study investigated the cytokine and chemokine profiles of HFMD patients from Singapore and Malaysia for the first time. Comparative cohort studies of EV-A71-associated HFMD cases revealed that the Malaysia cohort had a distinct profile from the Singapore cohort, and this could be partly attributed by different EV-A71 genotypes. As the isolation of CV-A6, instead of CV-A16, had become prevalent in the Singapore cohort, it was also of particular interest to study the differential cytokine and chemokine profiles. Our data revealed that overlapping as well as unique profiles exist between the two major causative clinical isolates in the Singapore cohort. Having a better understanding of the respective immunological profiles could be useful for more accurate HFMD diagnosis, which is imperative for disease transmission control until multi-valent vaccines and/or broad-spectrum anti-viral drugs become available.

Enteroviruses and Parechoviruses

Infections with enteroviruses and human parechoviruses are highly prevalent, particularly in neonates, where they may cause substantial morbidity and mortality. Individuals with B-cell-related immunodeficiencies are at risk for severe enteroviral infections, usually a chronic and fatal meningoencephalitis. In transplant recipients and patients with malignancy, enterovirus infections typically involve the respiratory tract, but cases of severe, disseminated infection have been described. The mainstay of diagnosis for enterovirus and human parechovirus infections involves the use of molecular diagnostic techniques. However, routine nucleic acid-detection methods for enteroviruses will not detect human parechoviruses. Laboratory diagnosis of these viral infections is important in determining a patient's prognosis and guiding clinical management.

Placental Massive Perivillous Fibrinoid Deposition Associated with Coxsackievirus A16-Report of a Case, and Review of the Literature

Massive placental perivillous fibrinoid deposition in the placenta is thought to be an immune-related condition associated with poor perinatal outcomes, including growth restriction and intrauterine fetal demise, with a high risk of recurrence. Rare cases have been associated with Coxsackievirus infection. We present such a case and review the literature.

Maternal environmental risk factors for congenital hydrocephalus: a systematic review

OBJECTIVE

Congenital hydrocephalus (CH) is one of the most frequent CNS congenital malformations, representing an entity with serious pathological consequences. Although several studies have previously assessed child-related risk factors associated with CH development, there is a gap of knowledge on maternal environmental risk factors related to CH. The authors have systematically assessed extrinsic factors in the maternal environment that potentially confer an increased risk of CH development.

METHODS

The Cochrane Library, MEDLINE, and EMBASE were systematically searched for works published between 1966 and December 2015 to identify all relevant articles published in English. Only studies that investigated environmental risk factors concerning the mother—either during gestation or pregestationally—were included.

RESULTS

In total, 13 studies (5 cohorts, 3 case series, 3 case-control studies, 1 meta-analysis, and 1 case report) meeting the inclusion criteria were identified. Maternal medication or alcohol use during gestation; lifestyle modifiable maternal pathologies such as obesity, diabetes, or hypertension; lack of prenatal care; and a low socioeconomic status were identified as significant maternal environmental risk factors for CH development. Maternal infections and trauma to the mother during pregnancy have also been highlighted as potential mother-related risk factors for CH.

CONCLUSIONS

Congenital hydrocephalus is an important cause of serious infant health disability that can lead to health inequalities among adults. The present study identified several maternal environmental risk factors for CH, thus yielding important scientific information relevant to prevention of some CH cases. However, further research is warranted to confirm the impact of the identified factors and examine their underlying behavioral and/or biological basis, leading to the generation of suitable prevention strategies.

The Genetic Basis of Hydrocephalus

Studies of syndromic hydrocephalus have led to the identification of >100 causative genes. Even though this work has illuminated numerous pathways associated with hydrocephalus, it has also highlighted the fact that the genetics underlying this phenotype are more complex than anticipated originally. Mendelian forms of hydrocephalus account for a small fraction of the genetic burden, with clear evidence of background-dependent effects of alleles on penetrance and expressivity of driver mutations in key developmental and homeostatic pathways. Here, we synthesize the currently implicated genes and inheritance paradigms underlying hydrocephalus, grouping causal loci into functional modules that affect discrete, albeit partially overlapping, cellular processes. These in turn have the potential to both inform pathomechanism and assist in the rational molecular classification of a clinically heterogeneous phenotype. Finally, we discuss conceptual methods that can lead to enhanced gene identification and dissection of disease basis, knowledge that will potentially form a foundation for the design of future therapeutics.

Skin infections in pregnancy

A wide array of infectious diseases can occur in pregnancy. Their acquisition, clinical presentation, and course during gestation may be altered due to an impairment of the maternal cellular immunity. Some infectious diseases can lead to serious consequences for the mother or the offspring, including congenital malformations. This review describes in detail the clinical presentation, course, management, and associated maternal and fetal risks of selected viral (varicella-zoster virus infections, condylomata acuminata), fungal (candida vulvovaginitis), bacterial (Lyme borreliosis), and parasitic (scabies) infections. The treatment options are critically reviewed. First-line therapies include acyclovir and varicella-zoster virus immunoglobulin for varicella-zoster virus infections, surgical modalities for genital warts, topical clotrimazole and oral fluconazole for Candida vulvovaginitis, amoxicillin and cefuroxime for Lyme borreliosis, and permethrin for scabies. A synopsis of maternal and fetal risks of other important infections is also included.

Tissue tropism, pathology and pathogenesis of enterovirus infection

Enteroviruses are very common and cause infections with a diverse array of clinical features. Enteroviruses are most frequently considered by practising pathologists in cases of aseptic meningitis, encephalitis, myocarditis and disseminated infections in neonates and infants. Congenital infections have been reported and transplacental transmission is thought to occur. Although skin biopsies during hand, foot and mouth disease are infrequently obtained, characteristic dermatopathological findings can be seen. Enteroviruses have been implicated in lower respiratory tract infections. This review highlights histopathological features of enterovirus infection and discusses diagnostic modalities for formalin-fixed paraffin-embedded tissues and their associated pitfalls. Immunohistochemistry can detect enterovirus antigen within cells of affected tissues; however, assays can be non-specific and detect other viruses. Molecular methods are increasingly relied upon but, due to the high frequency of asymptomatic enteroviral infections, clinical-pathological correlation is needed to determine significance. Of note, diagnostic assays on central nervous system or cardiac tissues from immunocompetent patients with prolonged disease courses are most often negative. Histopathological, immunohistochemical and molecular studies performed on clinical specimens also provide insight into enteroviral tissue tropism and pathogenesis.

Update on hand-foot-and-mouth disease

Hand-foot-and-mouth disease is a viral exanthem caused, primarily by Coxsackie A16 and enterovirus 71 with typical clinical features of fever, painful papules and blisters over the extremities and genitalia and an enanthem involving ulceration of the mouth, palate, and pharynx. Other enteroviruses have recently been noted to cause severe neurologic illness and paralysis (enterovirus 68) with variable cutaneous features. A recent outbreak of Coxsackie A6 infection has been seen worldwide with cases reported in the United States, Japan, Southeast Asia, and Europe. These cases have caused extensive cutaneous disease variants, some of which are not previously recognized in Coxsackie infection, namely vesicobullous and erosive eruptions, extensive cutaneous involvement, periorificial lesions, localization in areas of atopic dermatitis or in children with atopic dermatitis (the so-called eczema coxsackium), Gianotti-Crosti-like lesions, petechial/purpuric eruptions, delayed onychomadesis, and palmoplantar desquamation. Finally, adult cases appear to occur with this form of hand-foot-and-mouth disease, likely due to fecal-oral transmission in a household setting.

Infantile hydrocephalus: a review of epidemiology, classification and causes

Hydrocephalus is a common but complex condition caused by physical or functional obstruction of CSF flow that leads to progressive ventricular dilatation. Though hydrocephalus was recently estimated to affect 1.1 in 1000 infants, there have been few systematic assessments of the causes of hydrocephalus in this age group, which makes it a challenging condition to approach as a scientist or as a clinician. Here, we review contemporary literature on the epidemiology, classification and pathogenesis of infantile hydrocephalus. We describe the major environmental and genetic causes of hydrocephalus, with the goal of providing a framework to assess infants with hydrocephalus and guide future research.

Viral invasion of the amniotic cavity (VIAC) in the midtrimester of pregnancy

INTRODUCTION

The prevalence of viral infections in the amniotic fluid (AF) has not yet been ascertained. The aim of this study was to determine the prevalence of specific viral nucleic acids in the AF and its relationship to pregnancy outcome.

STUDY DESIGN

From a cohort of 847 consecutive women undergoing midtrimester amniocentesis, 729 cases were included in this study after exclusion of documented fetal anomalies, chromosomal abnormalities, unavailability of AF specimens and clinical outcomes. AF specimens were tested by quantitative real-time PCR for the presence of genome sequences of the following viruses: adenoviruses, herpes simplex virus (HSV), varicella zoster virus (VZV), human herpesvirus 6 (HHV6), human cytomegalovirus (HCMV), Epstein-Barr virus (EBV), parvovirus B19 and enteroviruses. Viral nucleic acid testing was also performed in maternal blood and cord blood in the population of women in whom AF was positive for viruses and in a control group of 29 women with AF negative for viral nucleic acids. The relationship between the presence of viruses and pregnancy and neonatal outcome was examined. The correlation between the presence of nucleic acids of viruses in the AF and the concentration of the cytokine interleukin-6 (IL-6) and the T cell chemokine CXCL-10 (or IP-10) in AF and maternal blood were analyzed.

RESULTS

Viral genome sequences were found in 16 of 729 (2.2%) AF samples. HHV6 was the most commonly detected virus (7 cases, 1.0%), followed by HCMV (6 cases, 0.8%), parvovirus B19 (2 cases, 0.3%) and EBV (1 case, 0.1%), while HSV, VZV, enteroviruses and adenoviruses were not found in this cohort. Corresponding viral DNA was also detected in maternal blood of six out of seven women with HHV6-positive AF and in the umbilical cord plasma, which was available in one case. In contrast, viral DNA was not detected in maternal blood of women with AF positive for parvovirus B19, HCMV, EBV or of women with AF negative for viruses. HHV6 genome copy number in AF and maternal blood was consistent with genomic integration of viral DNA and genetic infection in all women. There was no significant difference in the AF concentration of IL-6 and IP-10 between patients with and without VIAC. However, for HCMV, there was a significant relationship between viral copy number and IP-10 concentration in maternal blood and AF. The group of women with AF positive for viral DNA delivered at term healthy neonates without complications in 14 out of 16 cases. In one case of HHV6 infection in the AF, the patient developed gestational hypertension at term, and in another case of HHV6 infection in the AF, the patient delivered at 33 weeks after preterm premature rupture of membranes (PPROM).

CONCLUSION

Viral nucleic acids are detectable in 2.2% of AF samples obtained from asymptomatic women in the midtrimester. HHV6 was the most frequently detected virus in AF. Adenoviruses were not detected. Vertical transmission of HHV6 was demonstrated in one case.

Hepatitis E virus infection causing isolated fetal ascites: a case report

Maternal hepatitis infection, excepting hepatitis E, causing isolated fetal ascites with variable outcome has been reported previously. We present a case of maternal hepatitis E virus (HEV) infection causing isolated fetal ascites which resolved spontaneously during pregnancy and resulted in a term live-born baby with anti-HEV seropositivity. A 39-year-old primigravida woman was diagnosed with acute HEV infection at 15 weeks of gestation. Ultrasound at 19 weeks showed significant fetal ascites with abdominal calcifications. Fetal karyotype did not show any abnormality. Cord blood was positive for anti-HEV IgM and negative for other intrauterine infections. Ultrasound at 25 weeks showed partial resolution of fetal ascites with complete resolution at 30 weeks. She delivered a healthy baby at 38 completed weeks, with normal liver enzymes at birth and 1-month follow-up.

Increased risk of adverse pregnancy outcomes among women affected by herpangina

OBJECTIVE

This population-based study aimed to assess the relation between herpangina and adverse pregnancy outcomes: low birthweight (LBW), small for gestational age (SGA), and preterm delivery.

STUDY DESIGN

A total of 242 pregnant women who had singleton births and who visited ambulatory care centers for the treatment of herpangina were assessed, together with 1936 matched women as a comparison group. Conditional logistic regression analyses were performed to examine the risk of LBW, preterm birth, and SGA for mothers with herpangina and unaffected mothers.

RESULTS

Compared with pregnant women without herpangina, herpangina was associated with a 2.29- (95% confidence interval [CI], 1.42-3.69), 1.67- (95% CI, 1.04-2.68), and 1.63-fold (95% CI, 1.14-2.33) increased risk of having LBW, preterm, and SGA infants, respectively, after adjusting for family income and maternal and infant characteristics.

CONCLUSION

Our findings highlight a significant potential risk posed by herpangina, a usually mild disease, among pregnant women.

Human enterovirus 71 and hand, foot and mouth disease

Hand, foot and mouth disease (HFMD) is generally a benign febrile exanthematous childhood disease caused by human enteroviruses. The route of transmission is postulated to be faeco-oral in developing areas but attributed more to respiratory droplet in developed areas. Transmission is facilitated by the prolonged environmental survival of these viruses and their greater resistance to biocides. Serious outbreaks with neurological and cardiopulmonary complications caused by human enterovirus 71 (HEV-71) seem to be commoner in the Asian Pacific region than elsewhere in the world. This geographical predilection is unexplained but could be related to the frequency of intra- and inter-typic genetic recombinations of the virus, the host populations' genetic predisposition, environmental hygiene, and standard of healthcare. Vaccine development could be hampered by the general mildness of the illness and rapid genetic evolution of the virus. Antivirals are not readily available; the role of intravenous immunoglobulin in the treatment of serious complications should be investigated. Monitoring of this disease and its epidemiology in the densely populated Asia Pacific epicentre is important for the detection of emerging epidemics due to enteroviruses.

Enterovirus infections in neonates

Enteroviruses, which include echoviruses, coxsackie A and B viruses, polioviruses and the 'numbered' enteroviruses, are among the most common viruses causing disease in humans. A large proportion of enteroviral infections occur in neonates and infants. There is a wide spectrum of clinical manifestations that can be caused by enterovirus infection with varying degrees of severity. In the neonatal age group, enteroviral infections are associated with significant morbidity and mortality, particularly when infection occurs antenatally. This review provides a detailed overview of the epidemiology and clinical features of enterovirus infections in the neonatal period. In addition, laboratory features and diagnostic investigations are discussed. A review of the currently available data for prophylactic and therapeutic interventions, including antiviral therapy, is also presented.

Viruses and other infections in stillbirth: what is the evidence and what should we be doing?

In Australia, as in other developed countries, approximately 40-50% of stillbirths are of unknown aetiology. Emerging evidence suggests stillbirths are often multifactorial. The absence of a known cause leads to uncertainty regarding the risk of recurrence, which can cause extreme anguish for parents that may manifest as guilt, anger or bewilderment. Further, clinical endeavours to prevent recurrences in future pregnancies are impaired by lack of a defined aetiology. Therefore, efforts to provide an aetiological diagnosis of stillbirth impact upon all aspects of care of the mother, and inform many parts of clinical decision making. Despite the magnitude of the problem, that is 7 stillbirths per 1000 births in Australia, diagnostic efforts to discover viral aetiologies are often minimal. Viruses and other difficult to culture organisms have been postulated as the aetiology of a number of obstetric and paediatric conditions of unknown cause, including stillbirth. Reasons forwarded for testing stillbirth cases for infectious agents are non-medical factors, including addressing all parents' need for diagnostic closure, identifying infectious agents as a sporadic cause of stillbirth to reassure parents and clinicians regarding risk for future pregnancies, and to reduce unnecessary testing. It is clear that viral agents including rubella, human cytomegalovirus (CMV), parvovirus B19, herpes simplex virus (HSV), lymphocytic choriomeningitis virus (LCMV), and varicella zoster virus (VZV) may cause intrauterine deaths. Evidence for many other agents is that minimal or asymptomatic infections also occur, so improved markers of adverse outcomes are needed. The role of other viruses and difficult-to-culture organisms in stillbirth is uncertain, and needs more research. However, testing stillborn babies for some viral agents remains a useful adjunct to histopathological and other examinations at autopsy. Modern molecular techniques such as multiplex PCR, allow searches for multiple agents. Now that such testing is available, it is important to assess the clinical usefulness of such testing.

An overview of the evolution of enterovirus 71 and its clinical and public health significance

Since its discovery in 1969, enterovirus 71 (EV71) has been recognised as a frequent cause of epidemics of hand-foot-and-mouth disease (HFMD) associated with severe neurological sequelae in a small proportion of cases. There has been a significant increase in EV71 epidemic activity throughout the Asia-Pacific region since 1997. Recent HFMD epidemics in this region have been associated with a severe form of brainstem encephalitis associated with pulmonary oedema and high case-fatality rates. The emergence of large-scale epidemic activity in the Asia-Pacific region has been associated with the circulation of three genetic lineages that appear to be undergoing rapid evolutionary change. Two of these lineages (B3 and B4) have not been described previously and appear to have arisen from an endemic focus in equatorial Asia, which has served as a source of virus for HFMD epidemics in Malaysia, Singapore and Australia. The third lineage (C2) has previously been identified [Brown, B.A. et al. (1999) J. Virol. 73, 9969-9975] and was primarily responsible for the large HFMD epidemic in Taiwan during 1998. As EV71 appears not to be susceptible to newly developed antiviral agents and a vaccine is not currently available, control of EV71 epidemics through high-level surveillance and public health intervention needs to be maintained and extended throughout the Asia-Pacific region. Future research should focus on (1) understanding the molecular genetics of EV71 virulence, (2) identification of the receptor(s) for EV71, (3) development of antiviral agents to ameliorate the severity of neurological disease and (4) vaccine development to control epidemics. Following the successful experience of the poliomyelitis control programme, it may be possible to control EV71 epidemics if an effective live-attenuated vaccine is developed.