Enterovirus infections: diagnosis and treatment

National Surveillance of Acute Flaccid Paralysis Cases in Senegal during 2017 Uncovers the Circulation of Enterovirus Species A, B and C

Polioviruses have been eliminated in many countries; however, the number of acute flaccid paralysis cases has not decreased. Non-polio enteroviruses are passively monitored as part of the polio surveillance program. Previous studies have shown that some enteroviruses do not grow in conventional cell lines used for the isolation of poliovirus according to the WHO guidelines. In order to evaluate the presence of enteroviruses, real-time RT-PCR was performed on Human Rhabdomyosarcoma (RD)-positive and RD-negative stool samples. A total of 310 stool samples, collected from children under the age of 15 years with acute flaccid paralysis in Senegal in 2017, were screened using cell culture and real-time RT-PCR methods. The selected isolates were further characterized using Sanger sequencing and a phylogenetic tree was inferred based on VP1 sequences. Out of the 310 stool samples tested, 89 were positive in real-time RT-PCR. A total of 40 partial VP1 sequences were obtained and the classification analysis showed that 3 (13%), 19 (82.6%), and 1 (4.4%) sequences from 23 RD-positive non-polio enterovirus isolates and 3 (17.6%), 7 (41.1%), and 7 (41.1%) sequences from 17 RD-negative stool samples belonged to the species EV-A, B, and C, respectively. Interestingly, the EV-B sequences from RD-negative stool samples were grouped into three separate phylogenetic clusters. Our data exhibited also a high prevalence of the EV-C species in RD-negative stool samples. An active country-wide surveillance program of non-polio enteroviruses based on direct RT-PCR coupled with sequencing could be important not only for the rapid identification of the involved emergence or re-emergence enteroviruses, but also for the assessment of AFP’s severity associated with non-polio enteroviruses detected in Senegal.

Increased Incidence of Obstructive Sleep Apnea in Hospitalized Children After Enterovirus Infection: A Nationwide Population-based Cohort Study

BACKGROUND

We report the first nationwide population-based cohort study using Taiwan's National Health Insurance Research Database on the association between enterovirus (EV) infection and the incidence of sleep disorders in a pediatric population.

METHODS

Two matched groups of children under 18 years of age were included in the analyses for nonapneic sleep disorder and obstructive sleep apnea (OSA). Among them, 316 subjects were diagnosed with OSA during the surveillance period, including 182 in the EV infection group and 134 in the non-EV infection group.

RESULTS

Hospitalization because of EV infection was associated with OSA after adjusting for age, sex, urbanization atopic disease and perinatal complications (adjusted hazard ratio: 1.62, 95% confidence interval: 1.18-2.21; P = 0.003). An additional factor significantly associated with sleep apnea was allergic rhinitis (hazard ratio: 4.82, 95% confidence interval: 3.45-6.72).

CONCLUSIONS

Children with severe EV infection (ie, requiring hospitalization) carry a significantly higher risk of developing OSA, particularly in those with allergic rhinitis. As pediatric obstructive sleep apnea is a treatable sleep disorder, we emphasize regular follow-up and early detection in children with EV infection.

High frequency of Polio-like Enterovirus C strains with differential clustering of CVA-13 and EV-C99 subgenotypes in a cohort of Malawian children

Enteroviruses (EVs) are among the most commonly detected viruses infecting humans worldwide. Although the prevalence of EVs is widely studied, the status of EV prevalence in sub-Saharan Africa remains largely unknown. The objective of our present study was therefore to increase our knowledge on EV circulation in sub-Saharan Africa. We obtained 749 fecal samples from a cross-sectional study conducted on Malawian children aged 6 to 60 months. We tested the samples for the presence of EVs using real time PCR, and typed the positive samples based on partial viral protein 1 (VP1) sequences. A large proportion of the samples was EV positive (89.9%). 12.9% of the typed samples belonged to EV species A (EV-A), 48.6% to species B (EV-B) and 38.5% to species C (EV-C). More than half of the EV-C strains (53%) belonged to subgroup C containing, among others, Poliovirus (PV) 1-3. The serotype most frequently isolated in our study was CVA-13, followed by EV-C99. The strains of CVA-13 showed a vast genetic diversity, possibly representing a new cluster, 'F'. The majority of the EV-C99 strains grouped together as cluster B. In conclusion, this study showed a vast circulation of EVs among Malawian children, with an EV prevalence of 89.9%. Identification of prevalences for species EV-C comparable to our study (38.5%) have only previously been reported in sub-Saharan Africa, and EV-C is rarely found outside of this region. The data found in this study are an important contribution to our current knowledge of EV epidemiology within sub-Saharan Africa.

Clinical characteristics and molecular epidemiology of Enterovirus infection in infants <3 months in a referral paediatric hospital of Barcelona

Enterovirus (EV) infection is common in infants, but the information with regard to the molecular epidemiology and the associations between types and clinical variables is very scarce. This study includes 195 children <3 months old with fever, attended from March 2010 to December 2012 in an emergency department of a tertiary paediatric hospital in whom EV infection was confirmed by real-time PCR in blood and/or cerebrospinal fluid. Clinical and epidemiological data was prospectively collected. In 152 (77.9 %) patients, EVs could be typed. The most common type was Echovirus-5 (E5; 32, 21.1 %), followed by Echovirus-11 (E11; 18, 11.8 %), Echovirus-21 and Echovirus-25 (E21, E25; 11 each one, 7.2 %) and Coxsackievirus-B4 (CVB4; 6, 6.6 %). The majority of types appeared in spring, but E5 and E25 were found mainly during summer (p < 0.01). E21 was associated with high-grade fever (p < 0.01); E5 with exanthema (p = 0.03) and CVB4 tended to cause meningitis more often than the other types (p = 0.07).

CONCLUSION

The most common EV types were Echovirus-5 and Echovirus-11. Some significant associations between types and epidemiologic and clinical findings were observed. What is Known-What is New • Enteroviruses cause a normally benign illness in young infants, except in some cases. • The molecular epidemiology of Enterovirus infection is not well known in European countries. • This study describes a large number of infants with Enterovirus infection and shows the seasonality of different types, and their associations with epidemiologic and clinical variables.

Enterovirus D68: acute respiratory illness and the 2014 outbreak

Enteroviruses cause illnesses ranging from benign upper respiratory infections to severe meningitis and encephalitis. A recent uptick in the number of patients, many of them children, with respiratory infections caused by enterovirus 68 (EV-D68) has captured the attention of health care providers and public health administrators. In the United States, this type of infection was confirmed in 1152 people during 2014. This article examines recent trends in EV-D68 infections, reviewing past outbreaks and the 2014 outbreak, and describes the increasing cases of acute flaccid myelitis and their possible connection with EV-D68.

Acute meningoencephalitis associated with echovirus 9 infection in Sri Lanka, 2009

The aetiology of acute meningoencephalitis in Sri Lankan children and adults is poorly understood. This study was carried out to determine pathogens responsible for meningoencephalitis in Sri Lanka. A hospital-based cross-sectional study was performed using cerebrospinal fluid samples (22 adult and 17 pediatric) collected from August to December 2009 from patients clinically diagnosed with acute meningoencephalitis at two tertiary care hospitals in Sri Lanka. Routine microbiology for bacterial pathogens together with in-house RT-PCR and PCR assays for the detection of dengue viruses, Japanese encephalitis virus, West Nile virus, chikungunya virus, enteroviruses, mumps virus, measles virus, herpes simplex viruses types 1 and 2, and varicella zoster virus were performed. Bacterial pathogens were not isolated from any patient specimens. However, from nine of the paediatric patients aged 1 month to 10 years (mean age 5.2 years) echovirus 9 (E-9; family Picornaviridae, genus Enterovirus,species Enterovirus B ) was detected by RT-PCR. All nine patients presented with fever, six had headache, and seven had vomiting. Neck stiffness indicating meningitis was present in six of the patients. Phylogenetic analysis of partial VP1 and VP4-VP2 genes showed these E-9 strains to be most closely related to E-9 strains detected in CSF from Korea and France in 2005 and 2006. The remaining patients were negative for all other viruses tested. E-9 was the most common cause of acute meningoencephalitis in the tested paediatric population from Sri Lanka in 2009, which likely reflects circulation of this E-9 strain between Europe and Asia over several years.

A method for reporting and classifying acute infectious diseases in a prospective study of young children: TEDDY

BACKGROUND

Early childhood environmental exposures, possibly infections, may be responsible for triggering islet autoimmunity and progression to type 1 diabetes (T1D). The Environmental Determinants of Diabetes in the Young (TEDDY) follows children with increased HLA-related genetic risk for future T1D. TEDDY asks parents to prospectively record the child's infections using a diary book. The present paper shows how these large amounts of partially structured data were reduced into quantitative data-sets and further categorized into system-specific infectious disease episodes. The numbers and frequencies of acute infections and infectious episodes are shown.

METHODS

Study subjects (n = 3463) included children who had attended study visits every three months from age 3 months to 4 years, without missing two or more consecutive visits during the follow-up. Parents recorded illnesses prospectively in a TEDDY Book at home. The data were entered into the study database during study visits using ICD-10 codes by a research nurse. TEDDY investigators grouped ICD-10 codes and fever reports into infectious disease entities and further arranged them into four main categories of infectious episodes: respiratory, gastrointestinal, other, and unknown febrile episodes. Incidence rate of infections was modeled as function of gender, HLA-DQ genetic risk group and study center using the Poisson regression.

RESULTS

A total of 113,884 ICD-10 code reports for infectious diseases recorded in the database were reduced to 71,578 infectious episodes, including 74.0% respiratory, 13.1% gastrointestinal, 5.7% other infectious episodes and 7.2% febrile episodes. Respiratory and gastrointestinal infectious episodes were more frequent during winter. Infectious episode rates peaked at 6 months and began declining after 18 months of age. The overall infectious episode rate was 5.2 episodes per person-year and varied significantly by country of residence, sex and HLA genotype.

CONCLUSIONS

The data reduction and categorization process developed by TEDDY enables analysis of single infectious agents as well as larger arrays of infectious agents or clinical disease entities. The preliminary descriptive analyses of the incidence of infections among TEDDY participants younger than 4 years fits well with general knowledge of infectious disease epidemiology. This protocol can be used as a template in forthcoming time-dependent TEDDY analyses and in other epidemiological studies.

Frequency of enterovirus detection in blood samples of neonates admitted to hospital with sepsis-like illness in Kuwait

This study investigated the role of enteroviruses in sepsis-like illness among neonates in Kuwait. Serum samples from 139 consecutive neonates presenting with sepsis-like illness during a three and a half-year-period whose blood cultures were negative for bacterial pathogens were tested. Enterovirus RNA was detected by single-step reverse-transcription PCR (RT-PCR). Specific genotypes were identified by direct DNA sequencing of enteroviral genome. Serotype-specific antibodies in serum samples from some selected patients were detected by virus neutralization test using coxsackievirus B types (CBVs). All 139 neonates presented with sepsis-like illness and blood samples were uniformly negative for aerobic/anaerobic bacterial cultures. Fifty-six (40%) neonates had further complications of sepsis including carditis (n = 34) and multi-organ involvement (n = 22). Enterovirus RNA was detected by RT-PCR in 34 of 139 (24%) serum samples which is among the highest frequency reported so far in non-epidemic settings. Genotyping identified CBVs as most common enteroviruses, causing 19 of 34 (56%) enteroviral sepsis episodes in neonates. Of 34 carditis cases, 18 were positive for CBVs by serotyping including all 10 enterovirus RNA-positive samples. Only one fatality was observed due to liver failure in a neonate with hepatitis. Our data showed that enteroviruses are responsible for 24% of neonatal sepsis cases due to non-bacterial causes in Kuwait. The data indicate that enteroviruses should be considered in the differential diagnosis of sepsis-like illness among neonates, particularly those with negative blood cultures for bacterial pathogens.

Improving the diagnosis of meningitis due to enterovirus and herpes simplex virus I and II in a tertiary care hospital

BACKGROUND

Enterovirus and herpes simplex viruses are common causes of lymphocytic meningitis. The purpose of this study was to analyse the impact of the use molecular testing for Enteroviruses and Herpes simplex viruses I and II in all suspected cases of viral meningitis.

METHODS

From November 18, 2008 to November 17, 2009 (phase II, intervention), all patients admitted with suspected viral meningitis (with pleocytosis) had a CSF sample tested using a nucleic acid amplification test (NAAT). Data collected during this period were compared to those from the previous one-year period, i.e. November 18, 2007 to November 17, 2008 (phase I, observational), when such tests were available but not routinely used.

RESULTS

In total, 2,536 CSF samples were assessed, of which 1,264 were from phase I, and 1,272 from phase II. Of this total, a NAAT for Enterovirus was ordered in 123 cases during phase I (9.7% of the total phase I sample) and in 221 cases in phase II (17.4% of the total phase II sample). From these, Enterovirus was confirmed in 35 (28.5%, 35/123) patients during phase I and 71 (32.1%, 71/221) patients during phase II (p = 0.107). The rate of diagnosis of meningitis by HSV I and II did not differ between the groups (13 patients, 6.5% in phase I and 13, 4.7% in phase II) (p = 1.0), from 200 cases in phase I and 274 cases in phase II.

CONCLUSIONS

The number of cases diagnosed with enteroviral meningitis increased during the course of this study, leading us to believe that the strategy of performing NAAT for Enterovirus on every CSF sample with pleocytosis is fully justified.

Democratizing molecular diagnostics: the GeneXpert(®) enterovirus assay

BACKGROUND

Few clinical scenarios are as diagnostically demanding as the workup of acute meningitis in the emergency room setting. In humans, most cases of meningitis are due to enteroviral infection, which usually resolves with supportive care and does not generally require hospitalization. The difficulty in evaluating meningitis is often related to its nonspecific presentation; rapid identification of the underlying etiologic agent is critical to selection of the most appropriate course of therapy.

OBJECTIVE

To develop a rapid, automated polymerase chain reaction-based test for enteroviral meningitis that can be run on demand, and to make the test easy enough to operate that most hospital laboratories can offer it on an immediate basis in order to provide maximum medical impact.

METHODS

A sensitive and specific test on the GeneXpert was developed for detection of enteroviral RNA in cerebrospinal fluid. The automated test was carried out in a disposable GeneXpert cartridge, which conducts the steps of nucleic acid purification, amplification and detection of enteroviral genomic RNA in ∼ 2 h. Preclinical and clinical studies showed sensitivities of 97.1 and 98%, respectively, and specificities of 100 and 97.1%, respectively. In February 2006, the test received FDA clearance as an aid in the diagnosis of viral meningitis.

CONCLUSIONS

Rapid and accurate molecular diagnostic testing for enterovirus infection provides clinicians with information they need to make the best patient decisions in managing patients with meningitis. The GeneXpert enterovirus assay features on-demand availability and a level of simplicity that allows nearly any hospital laboratory to offer a sophisticated test that was once the exclusive domain of reference laboratories.

Implementation of the Cepheid Xpert EV assay for rapid detection of enteroviral meningitis: experience of a tertiary care center and a technical review

AIMS

Rapid molecular detection of enterovirus in cerebrospinal fluid (CSF) has revolutionized the diagnosis and treatment modalities of patients with meningitis and largely affected cost of unnecessary antibiotic use and length of stay in hospitals.

MATERIALS AND METHODS

Between January 2010 and July 2012, we tested 220 CSF samples on the GeneXpert DX real-time polymerase chain reaction system (by Cepheid) using the Xpert EV kit assays. In addition, we reported 14 sample results cross-validated with an external referral laboratory as well as the results of external proficiency testing.

RESULTS

Out of all tested samples, 19% were positive for enterovirus. Furthermore, all referred and proficiency testing specimens were concordant with the peer-reviewed and tested samples.

CONCLUSION

Implementation of the Cepheid Xpert EV assay for rapid detection of enteroviral meningitis has been successful in our laboratory. This molecular diagnostic test is currently utilized by our staff physicians as a major tool in assessment and management of patients with meningitis.

Antenatal and postnatal diagnosis of coxsackie b4 infection: case series

Enteroviruses are a common cause of neonatal infection. In particular, Coxsackie B viruses are often associated with severe, fatal disease. The antenatal diagnosis of Coxsackie B viral infections is uncommon. We present a unique case of Coxsackie B4 virus ventriculitis and myocarditis causing fetal hydrops at 22 weeks gestation. Transmission was inferred by viral isolation from the amniotic fluid and by placental pathology. We also describe two additional cases of fatal neonatal Coxsackie B4 infection complicated by myocarditis and encephalitis with cerebral necrosis in a 4-day-old female and by myocarditis, spinal leptomeningitis, and hepatitis in a 4-day-old male. Transplacental acquisition of infection carries a poor prognosis. We propose that Coxsackie B virus should be considered in the investigation of nonimmune hydrops, particularly in the presence of cardiac dysfunction.

Low prevalence of invasive bacterial infection in febrile infants under 3 months of age with enterovirus infection

Infants under 3 months of age with fever without source (FWS) generally undergo a full, invasive septic evaluation to exclude invasive bacterial infection (IBI). Enterovirus (EV) infections are mostly banal and self-limiting and show a high prevalence rate at this age. We aimed to investigate the prevalence of IBI in EV-infected and uninfected infants under 3 months of age with FWS. This was a prospective observational cohort study of infants aged <90 days who were admitted because of FWS. As per protocol, blood and urine analysis and culture were obtained in all cases, and RNA EV from blood and/or cerebrospinal fluid samples was determined by real-time PCR. Three hundred and eighty-one previously healthy infants with FWS were included. EV infection was diagnosed in 64 children (16.8%; 95% confidence interval, 13.2-20.9%) and showed an uneventful evolution in all cases. Laboratory markers of infection were consistently lower in EV-infected patients; only one case of IBI (1.6%) was observed in an EV-infected patient as compared with 25.2% in EV-negative infants (p <0.001). Intravenous antibiotic use and length of stay were no different in EV-infected and uninfected patients. In our study, febrile infants (<90 days) diagnosed with EV infection showed a low risk of IBI when compared with uninfected patients. The systematic investigation of EV infection in young infants with FWS may allow a more conservative approach to the management of these patients. Further studies on this diagnostic approach are needed.

Experimental human rhinovirus and enterovirus interspecies recombination

Human rhinoviruses (HRVs) and enteroviruses (HEVs), two important human pathogens, are non-enveloped, positive-sense RNA viruses of the genus Enterovirus within the family Picornaviridae. Intraspecies recombination is known as a driving force for enterovirus and, to a lesser extent, rhinovirus evolution. Interspecies recombination is much less frequent among circulating strains, and supporting evidence for such recombination is limited to ancestral events, as shown by recent phylogenetic analyses reporting ancient HRV-A/HRV-C, HEV-A/HEV-C and HEV-A/HEV-D recombination mainly at the 5'-untranslated region (5' UTR)-polyprotein junction. In this study, chimeric genomes were artificially generated using the 5' UTR from two different clinical HRV-C strains (HRV-Ca and HRV-Cc), an HRV-B strain (HRV-B37) and an HEV-A strain (HEV-A71), and the remaining part of the genome from an HRV-A strain (HRV-A16). Whilst the chimeric viruses were easily propagated in cell culture, the wild-type HRV-A16 retained a replication advantage, both individually and in competition experiments. Assessment of protein synthesis ability did not show a correlation between translation and replication efficiencies. These results reflect the interchangeability of the 5' UTR, including its functional RNA structural elements implicated in both genome translation and replication among different enterovirus species. The 5' UTR-polyprotein junction therefore represents a theoretic interspecies recombination breakpoint. This recombination potential is probably restricted by the need for co-infection opportunities and the requirement for the progeny chimera to outcompete the parental genomes' fitness, explaining the rare occurrence of such events in vivo.

Evaluation of a rapid and completely automated real-time reverse transcriptase PCR assay for diagnosis of enteroviral meningitis

Nucleic acid amplification tests (NAATs) for enterovirus RNA in cerebrospinal fluid (CSF) have emerged as the new gold standard for diagnosis of enteroviral meningitis, and their use can improve the management and decrease the costs for caring for children with enteroviral meningitis. The Xpert EV assay (Cepheid, Sunnyvale, CA) is a rapid, fully automated real-time PCR test for the detection of enterovirus RNA that was approved by the U.S. Food and Drug Administration for in vitro diagnostic use in March 2007. In this multicenter trial we established the clinical performance characteristics of the Xpert EV assay in patients presenting with meningitis symptoms relative to clinical truth. Clinical truth for enteroviral meningitis was defined as clinical evidence of meningitis, the absence of another detectable pathogen in CSF, and detection of enterovirus in CSF either by two reference NAATs or by viral culture. A total of 199 prospectively and 235 retrospectively collected specimens were eligible for inclusion in this study. The overall prevalence of enteroviral meningitis was 26.04%. The Xpert EV assay had a sensitivity of 94.69% (90% confidence interval [CI] = 89.79 to 97.66%), specificity of 100% (90% CI = 99.07 to 100%), positive predictive value of 100%, negative predictive value of 98.17, and an accuracy of 98.62% relative to clinical truth. The Xpert EV assay demonstrated a high degree of accuracy for diagnosis of enteroviral meningitis. The simplicity and on-demand capability of the Xpert EV assay should prove to be a valuable adjunct to the evaluation of suspected meningitis cases.

Forecasting the economic value of an Enterovirus 71 (EV71) vaccine

Enterovirus 71 (EV71) is a growing public health concern, especially in Asia. A surge of EV71 cases in 2008 prompted authorities in China to go on national alert. While there is currently no treatment for EV71 infections, vaccines are under development. We developed a computer simulation model to determine the potential economic value of an EV71 vaccine for children (<5 years old) in China. Our results suggest that routine vaccination in China (EV71 infection incidence ≈0.04%) may be cost-effective when vaccine cost is $25 and efficacy ≥70% or cost is $10 and efficacy ≥50%. For populations with higher infection risk (≥0.4%), a $50 or $75 vaccine would be highly cost-effective even when vaccine efficacy is as low as 50%.

Severe enterovirus disease in febrile neonates

INTRODUCTION

Fever in newborn infants may be due to an invasive infection with potential morbidity and mortality. Our aim was to describe the characteristics and outcome of group of febrile neonates with severe enterovirus infection compared to a group of neonates with severe bacterial infection.

PATIENTS AND METHODS

Prospective study including all neonates (<29 days old) admitted to a teaching hospital for fever (>38 degrees C), with positive bacterial cultures or enterovirus detection in sterile samples, from September 2003 to December 2004. Clinical information, analytical data at admission (complete leukocyte count and C-reactive protein concentrations), blood, urine, and cerebrospinal fluid culture results, molecular detection of enterovirus by polymerase chain reaction (PCR), and outcome were recorded.

RESULTS

Invasive bacterial infections were observed in 62 patients: urinary tract infection (n=57, including 8 cases of bacteremia), sepsis (n=3), and meningitis (n=2). Molecular tests for enterovirus were positive in 10 patients. C-reactive protein values were significantly higher in neonates with bacterial infection than in those with enterovirus infection (62,3 versus 9mg/L, P=0,008). Two patients with Streptococcus agalactiae meningitis, 1 with Staphylococcus aureus sepsis and 3 with enterovirus infection (manifested as myocarditis, hepatitis, and meningoencephalitis) required admission to the pediatric intensive care unit. Among these, 1 newborn with S. agalactiae and 2 of the 3 with enterovirus infection died.

CONCLUSIONS

In our series, enterovirus infection was an important cause of severe invasive disease. Specific viral diagnosis can contribute to the management of febrile neonates.

Eight-plex PCR and liquid-array detection of bacterial and viral pathogens in cerebrospinal fluid from patients with suspected meningitis

We here report on the development of a novel multiplex PCR with product detection in a Luminex 100 suspension array system. The assay covers the nine most important bacterial and viral pathogens found in Danish meningitis patients. The microorganisms include Neisseria meningitidis, Streptococcus pneumoniae, Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, Streptococcus agalactiae, herpes simplex virus types 1 and 2, and varicella-zoster virus. The study was based on 1,187 samples, of which 55 were found to be positive by PCR. The assay was found to have an excellent sensitivity and an excellent specificity compared to the results of a "gold standard," defined by routine laboratory tests, for the two most important pathogens, S. pneumoniae (95 and 99.1%, respectively) and N. meningitidis (100 and 99.7%, respectively). The method provides a valuable supplement to the traditional microscopy and culture of cerebrospinal fluid (CSF) samples in a routine diagnostic setting, and results can be available within 1 workday. The method is suitable for use for the initial screening and identification of nine important microorganisms in CSF samples from patients with suspected meningitis. Compared to microscopy and culture of CSF, this rapid and sensitive method will support physicians with the selection of the appropriate antimicrobial agents and the initiation of timely treatment in the absence of live microorganisms in the CSF.

Synthesis and anti-CVB 3 evaluation of substituted 5-nitro-2-phenoxybenzonitriles

The synthesis and SAR of a series of 60 substituted 2-phenoxy-5-nitrobenzonitriles (analogues of MDL-860) as inhibitors of enterovirus replication (in particular of coxsackievirus B3 (CVB 3)) are reported. Several of the analogues inhibited CVB 3 and other enteroviruses at low-micromolar concentrations.

A case report of a premature infant with coxsackie B1 meningitis

This case report describes a 36-week gestational age infant diagnosed with coxsackie B1 meningitis at 20 days of age. A head ultrasound 5 days after diagnosis was consistent with cystic periventricular leukomalacia. The scientific literature does not clearly elucidate differences between bacterial and viral infections in infants. When difficulties arise, it is pertinent to consider a viral etiology for the underlying illness and obtain a detailed maternal and infant history focusing on clinical symptoms, seasonality, geographic location, exposure, and incubation period. Polymerase chain reaction is a rapid and sensitive diagnostic test for the identification of enteroviruses in cerebrospinal fluid, blood, urine, and throat specimens and should be performed as part of the general workup in the evaluation of a febrile infant with sepsis. In retrospect, it may have established an earlier diagnosis of meningitis, consequently preventing the unnecessary use of antibiotics, potentially decreasing the length of hospitalization, and eliminating the need for more detailed investigations to rule out other etiological factors. In addition, treatment with pleconaril may have affected the severity of the encephalitis. This article reviews the pathogenesis, clinical manifestations, and differential diagnoses of enteroviral infections, specifically focusing on the prevention, treatment, and prognosis of the disease and the implications for clinical practice.

Routine cerebrospinal fluid enterovirus polymerase chain reaction testing reduces hospitalization and antibiotic use for infants 90 days of age or younger

OBJECTIVE

The goal was to evaluate the impact of cerebrospinal fluid enterovirus polymerase chain reaction testing on the length of hospitalization and the duration of antibiotic use for infants < or = 90 days of age with suspected aseptic meningitis.

METHODS

This retrospective cohort study was conducted at an urban, tertiary-care children's hospital. Data were collected for 478 patients < or = 90 days of age for whom cerebrospinal fluid enterovirus polymerase chain reaction testing was performed during the enteroviral seasons of 2000 to 2006. The length of hospitalization and the duration of antibiotic use were assessed.

RESULTS

Cerebrospinal fluid enterovirus polymerase chain reaction test results were positive for 154 patients (34.8%). The mean length of stay was 3.65 days. The median polymerase chain reaction turnaround time was 23 hours. In multivariate analysis, having a positive cerebrospinal fluid enterovirus polymerase chain reaction result was associated with a 1.54-day decrease in the length of stay and a 33.7% shorter duration of antibiotic use. When patients were stratified according to the presence or absence of pleocytosis, both groups demonstrated significant reductions in the length of stay with positive cerebrospinal fluid enterovirus polymerase chain reaction results (1.32 and 1.38 days, respectively). Furthermore, increasing the polymerase chain reaction turnaround time by 24 hours increased the length of stay by 13.6% for patients with positive cerebrospinal fluid enterovirus polymerase chain reaction results.

CONCLUSIONS

Having positive cerebrospinal fluid enterovirus polymerase chain reaction results decreases the length of hospitalization and the duration of antibiotic use for young infants. These results support the routine use of this test during periods of peak enterovirus prevalence.

Multicenter beta trial of the GeneXpert enterovirus assay

The GeneXpert Dx system (Cepheid, Sunnyvale, CA) is a fully integrated and automated nucleic acid sample preparation, amplification, and real-time detection system. It consists of an instrument, a personal computer, and disposable fluidic cartridges. The analytical sensitivity and specificity of the GeneXpert enterovirus assay (GXEA) were determined with a panel of 63 different enterovirus serotypes and 24 other microorganisms, respectively. The potential for blood, hemoglobin, white blood cells, and excess protein to interfere with the assay was also assessed. The performance parameters of the GXEA were determined at three sites with 102 cerebrospinal fluid (CSF) samples obtained from patients with suspected meningitis. All samples were tested for enterovirus RNA with locally developed reverse transcription-PCR (RT-PCR) assays at the trial sites and with a seminested RT-PCR and an analyte-specific reagent (Cepheid) at a reference laboratory. The 5' nontranslated region was the target for all of the PCR assays except the seminested RT-PCR, which amplified a VP1 sequence. The VP1 amplicon was sequenced to identify the enterovirus types. Consensus reference laboratory RT-PCR results were used to classify cases of enteroviral meningitis. The GXEA detected all of the enterovirus serotypes and none of the other microorganisms tested except rhinovirus 16. The assay was unaffected by moderate amounts of blood or blood components. Thirty-six (35%) of the CSF samples tested had at least one positive PCR result. Eleven different enterovirus serotypes were identified in the positive samples. The GXEA had a sensitivity of 97.1% (95% confidence interval [CI], 84.7 to 99.9%) and a specificity of 100% (95% CI, 94.6 to 100%) for the diagnosis of enteroviral meningitis.

Childhood viral exanthems

Many viral infections exhibit cutaneous lesions. Recognition of the exanthems associated with these infections and the broader clinical scenarios in which they occur can lead to more rapid diagnosis and appropriate treatment for affected patients.

Case studies in cost effectiveness of molecular diagnostics for infectious diseases: pulmonary tuberculosis, enteroviral meningitis, and BK virus nephropathy

Pathogen genome amplification is used to detect and identify microorganisms, assess response to therapy, and detect mutations associated with drug resistance. Nucleic acid amplification tests have been shown to be superior to conventional culture-based testing methods in many circumstances. However, the enthusiasm for the technology in clinical laboratories may be decreased by the practical considerations of cost, complexity of the technology, and lack of US Food and Drug Administration-approved tests. The impact of nucleic acid amplification tests on the diagnosis and management of patients with tuberculosis, enteroviral meningitis, and BK virus transplant nephropathy will be examined, with an emphasis on the potential for health care cost savings.

Molecular and epidemiologic analysis of enterovirus B neurological infection in Argentine children

BACKGROUND

Human enteroviruses are one of the major causes of central nervous system (CNS) infections in pediatrics.

STUDY DESIGN

We have studied 1242 children under 15 years old with suspicion of CNS infection from January 1998 to December 2003. CSF was obtained and molecular typing of human enterovirus B serotypes was performed by RT-PCR and sequencing of the N-terminal part of VP1 gene.

RESULTS

According to the clinical syndromes, patients were grouped as aseptic meningitis (n=654, 52.6%), encephalitis (n=239, 19.2%), febrile seizures (n=153, 12.3%), febrile infant (n=84, 6.7%), neonatal disease (n=70, 5.6%),), acute flaccid paralysis (n=31, 2.4%) and acute disseminated encephalomyelitis (n=11, 0.9%). HEV was detected in 335/1242 CSF samples (26.97%) and was associated to aseptic meningitis (n=243, 72.5%); febrile infant (n=31, 9.2%); neonatal infection (n=26, 7.7%); encephalitis (n=25, 7.5%), febrile seizures (n=9, 2.68%); acute flaccid paralysis (n=1, 0.3%). Seasonal incidence of HEV-B species was analyzed showing that in Buenos Aires infections occur mainly during late spring and summer. Molecular serotyping was completed in 60/335 samples. Echovirus 30, Echovirus 9, Coxsackie B3 to B5 and Echovirus 33 were the most frequently identified.

CONCLUSIONS

We showed that HEV are responsible for a considerable proportion of hospitalizations in children with central nervous system compromise reaching 27% of overall etiology.

Development and evaluation of a real-time RT-PCR assay on the LightCycler for the rapid detection of enterovirus in cerebrospinal fluid specimens

BACKGROUND

Detection of enteroviral nucleic acid in cerebrospinal fluid (CSF) specimens has been demonstrated to improve the management of patients with aseptic meningitis.

OBJECTIVE

To develop on the LightCycler (LC) instrument a real-time RT-PCR assay based on TaqMan technology for the detection of enteroviruses (EV) in cerebrospinal fluid (CSF) specimens.

STUDY DESIGN

After evaluation of the analytical performances, seventy-four CSF samples collected prospectively from patients who have been suspected for a clinical diagnosis of meningitis were evaluated by two LC real-time RT-PCR assays and one conventional RT-PCR assay.

RESULTS

Our assay detected all 30 different EV species tested, whereas no reactivity was observed with other neurotropic viruses. The analytical sensitivity of both LC RT-PCR real-time assays was 1 TCID50 for LC one-step and two-step RT-PCR assays. Results for LC one-step and LC two-step RT-PCR were compared to results of the conventional RT-PCR: of the 74 CSF specimens tested, 11 were positive and 56 were negative by all methods. Four other specimens were positive for EV by at least two of the methods (including the LC two-step RT-PCR and the conventional RT-PCR), two other CSF specimens were positive by the LC two-step RT-PCR assay only, and another one CSF specimen was positive by the LC one-step RT-PCR assay only. No CSF specimens were negative by the LC two-step RT-PCR assay and positive by the conventional RT-PCR assay. The sensitivity, specificity, positive and negative predictive values of both LC RT-PCR assays by using conventional RT-PCR as the "gold standard" were, respectively, 73.3, 98.3, 91.7, 93.5% for the LC one-step RT-PCR and 100, 96.6, 88.2, 100% for the LC two-step RT-PCR. There was substantial agreement between the three assays (k=0.80).

CONCLUSIONS

The LC two-step RT-PCR assay is a rapid, sensitive and reliable method which can be routinely performed with CSF samples for diagnosis of EV infection and is an important improvement for optimal patient management.

Molecular methods for diagnosis of viral encephalitis

Hundreds of viruses cause central nervous system (CNS) disease, including meningoencephalitis and postinfectious encephalomyelitis, in humans. The cerebrospinal fluid (CSF) is abnormal in >90% of cases; however, routine CSF studies only rarely lead to identification of a specific etiologic agent. Diagnosis of viral infections of the CNS has been revolutionized by the advent of new molecular diagnostic technologies to amplify viral nucleic acid from CSF, including PCR, nucleic acid sequence-based amplification, and branched-DNA assay. PCR is ideally suited for identifying fastidious organisms that may be difficult or impossible to culture and has been widely applied for detection of both DNA and RNA viruses in CSF. The technique can be performed rapidly and inexpensively and has become an integral component of diagnostic medical practice in the United States and other developed countries. In addition to its use for identification of etiologic agents of CNS disease in the clinical setting, PCR has also been used to quantitate viral load and monitor duration and adequacy of antiviral drug therapy. PCR has also been applied in the research setting to help discriminate active versus postinfectious immune-mediate disease, identify determinants of drug resistance, and investigate the etiology of neurologic disease of uncertain cause. This review discusses general principles of PCR and reverse transcription-PCR, including qualitative, quantitative, and multiplex techniques, with comment on issues of sensitivity, specificity, and positive and negative predictive values. The application of molecular diagnostic methods for diagnosis of specific infectious entities is reviewed in detail, including viruses for which PCR is of proven efficacy and is widely available, viruses for which PCR is less widely available or for which PCR has unproven sensitivity and specificity, and nonviral entities which can mimic viral CNS disease.

Isolation and molecular identification of echovirus 13 isolated from patients of aseptic meningitis in Korea, 2002

During 2002, several epidemics of aseptic meningitis were attributed to echovirus 13 in Korea. The causative agents of these outbreaks were isolated and identified using rhabdosarcoma cells, HEp-2 and Buffalo green monkey kidney cells, and a neutralization test using monospecific antiserum. Fifty-four echovirus 13 isolates were isolated from patients with aseptic meningitis in the provinces, Seoul, Kyonggi, Gwangju, Jeonju, Busan, and Ulsan. Symptoms associated with aseptic meningitis infection in patients included the occurrence of headaches and mild fever. Molecular characterization of echovirus 13 samples was achieved by sequence and phylogenetic analyses on partial VP1 sequences from 20 Korean isolates and 10 foreign isolates listed in Genbank. Minor variation was observed among the Korean isolates, which formed a unique cluster with isolates of German and Japanese origin. The marked similarities between isolates could be attributed to a relatively recent arrival of the virus in Korea. This is the first such investigation of aseptic meningitis caused by echovirus 13 on the Korean peninsula.

Selective human enterovirus and rhinovirus inhibitors: An overview of capsid-binding and protease-inhibiting molecules

The absence of effective vaccines for most viral infections highlights an urgent necessity for the design and development of effective antiviral drugs. Due to the advancement in virology since the late 1980s, several key events in the viral life cycle have been well delineated and a number of molecular targets have been validated, culminating in the emergence of many new antiviral drugs in recent years. Inhibitors against enteroviruses and rhinoviruses, responsible for about half of the human common colds, are currently under active investigation. Agents targeted at either viral protein 1 (VP1), a relatively conserved capsid structure mediating viral adsorption/uncoating process, or 3C protease, which is highly conserved among different serotypes and essential for viral replication, are of great potential to become antipicornavirus drugs.

Mutation in enterovirus 71 capsid protein VP1 confers resistance to the inhibitory effects of pyridyl imidazolidinone

Enterovirus 71 is one of the most important pathogens in the family of Picornaviridae that can cause severe complications in the postpoliovirus era, such as encephalitis, pulmonary edema, and even death. Pyridyl imidazolidinone is a novel class of potent and selective human enterovirus 71 inhibitor. Pyridyl imidazolidinone was identified by using computer-assisted drug design. This virologic investigation demonstrates that BPR0Z-194, one of the pyridyl imidazolidinones, targets enterovirus 71 capsid protein VP1. Time course experiments revealed that BPR0Z-194 effectively inhibited virus replication in the early stages, implying that the compound can inhibit viral adsorption and/or viral RNA uncoating. BPR0Z-194 was used to select and characterize the drug-resistant viruses. Sequence analysis of the VP1 region showed that the resistant variants differed consistently by seven amino acids in VP1 region from their parental drug-sensitive strains. Site-directed mutagenesis of enterovirus 71 infectious cDNA revealed that a single amino acid alteration at the position 192 of VP1 can confer resistance to the inhibitory effects of BPR0Z-194.

SPECT scans for monitoring response to pleconaril therapy in chronic enteroviral meningoencephalitis

Chronic enteroviral meningoencephalitis (CEMA) is a rare complication of immunodeficient individuals and may present as insidious intellectual deterioration. Diagnosis requires isolation or PCR identification of enterovirus from the CSF. Pleconaril, a novel anti-picornaviral compound is available on a compassionate release basis to treat patients with potentially life threatening enteroviral infection. Non-invasive neuroimaging is an important new technique for both the diagnosis of encephalitis and as an objective assessment of response to treatment. We report two immunodeficient patients, one with common variable immunodeficiency and one with HIV, with an insidious presentation of CEMA. In both patients, perfusion single photon emission tomography scans were effective in monitoring treatment, correlating with clinical and virological response to pleconaril.

Rapid and sensitive routine detection of all members of the genus enterovirus in different clinical specimens by real-time PCR

We developed a rapid and sensitive method for the routine detection of all members of the enterovirus genus in different clinical specimens by using real-time TaqMan quantitative PCR. Multiple primer and probe sets were selected in the highly conserved 5'-untranslated region of the enterovirus genome. Our assay detected all 60 different enterovirus species tested, whereas no reactivity was observed with the viruses from the other genera of the picornaviridae family, e.g., hepatovirus and parechovirus. Weak cross-reactivity was observed with 7 of the 90 different high-titer rhinovirus stocks but not with rhinovirus-positive clinical isolates. Analysis of a well-characterized reference panel containing different enteroviruses at various concentrations demonstrated that the enterovirus real-time TaqMan PCR is as sensitive as most of the currently used molecular detection assays. Evaluation of clinical isolates demonstrated that the assay is more sensitive than the "gold standard" method, i.e., viral culture. Moreover, the PCR assay can be used on different clinical specimens, such as plasma, serum, nose and throat swabs, cerebrospinal fluid, and bronchoalveolar lavage, without apparent inhibition. Our data demonstrate that the real-time TaqMan PCR is a rapid and sensitive assay for the detection of enterovirus infection. The assay has a robust character and is easily standardized, which makes it an excellent alternative for the conventional time-consuming viral culture.