Diagnosis of enterovirus infection in the first 2 months of life by real-time polymerase chain reaction

Enteroviral Infections in the First Three Months of Life

Enteroviruses (EVs) are an important source of infection in the paediatric age, with most cases concerning the neonatal age and early infancy. Molecular epidemiology is crucial to understand the circulation of main serotypes in a specific area and period due to their extreme epidemiological variability. The diagnosis of EVs infection currently relies on the detection of EVs RNA in biological samples (usually cerebrospinal fluid and plasma, but also throat swabs and feces) through a polymerase chain reaction assay. Although EVs infections usually have a benign course, they sometimes become life threatening, especially when symptoms develop in the first few days of life. Mortality is primarily associated with myocarditis, acute hepatitis, and multi-organ failure. Neurodevelopmental sequelae have been reported following severe infections with central nervous system involvement. Unfortunately, at present, the treatment of EVs infections is mainly supportive. The use of specific antiviral agents in severe neonatal infections has been reported in single cases or studies including few neonates. Therefore, further studies are needed to confirm the efficacy of these drugs in clinical practice.

Enterovirus, parechovirus, adenovirus and herpes virus type 6 viraemia in fever without source

OBJECTIVES

To evaluate the potential associations between fever without a source (FWS) in children and detection of human enterovirus (HEV), human parechovirus (HPeV), adenovirus (AdV) and human herpesvirus type 6 (HHV-6) in the plasma; and to assess whether the detection of viruses in the plasma is associated with a reduced risk of serious bacterial infection (SBI) and antibiotic use.

DESIGN AND SETTING

Between November 2015 and December 2017, this prospective, single-centre, diagnostic study tested the plasma of children <3 years old with FWS. Real-time (reverse-transcription) PCR for HEV, HPeV, AdV and HHV-6 was used in addition to the standardised institutional work-up. A control cohort was also tested for the presence of viruses in their blood.

RESULTS

HEV, HPeV, AdV and HHV-6 were tested for in the plasma of 135 patients of median age 2.4 months old. At least one virus was detected in 47 of 135 (34.8%): HEV in 14.1%, HHV-6 in 11.1%, HPeV in 5.9% and AdV in 5.2%. There was no difference in antibiotic use between patients with or without virus detected, despite a relative risk of 0.2 for an SBI among patients with viraemia. Controls were less frequently viraemic than children with FWS (6.0% vs 34.8%; p<0.001).

CONCLUSIONS

HEV, HPeV, AdV and HHV-6 are frequently detected in the plasma of children with FWS. Antibiotic use was similar between viraemic and non-viraemic patients despite a lower risk of SBI among patients with viraemia. Point-of-care viral PCR testing of plasma might reduce antibiotic use and possibly investigations and admission rates in patients with FWS.

TRIAL REGISTRATION NUMBER

NCT03224026.

Immune Evasion of Enteroviruses Under Innate Immune Monitoring

As a major component of immunological defense against a great variety of pathogens, innate immunity is capable of activating the adaptive immune system. Viruses are a type of pathogen that proliferate parasitically in cells and have multiple strategies to escape from host immune pressure. Here, we review recent studies of the strategies and mechanisms by which enteroviruses evade innate immune monitoring.

Prevalence and characteristics of human parechovirus and enterovirus infection in febrile infants

BACKGROUND

Human parechovirus (HPeV) and human non-polio enterovirus (EV) are important causes of fever without source (FWS) in young infants. Their prevalence and clinical characteristics are largely unknown in Asian countries. This study was conducted to elucidate the epidemiology and clinical characteristics of HPeV and EV infection in febrile young infants in Japan.

METHODS

During February 2010-August 2015, we obtained 53 stool, 44 throat swab, and 20 cerebrospinal fluid samples from 56 infants (<3 months) with FWS at a single hospital. To each sample, we applied reverse transcription-polymerase chain reaction for HPeV and EV. We compared the clinical characteristics of HPeV and EV patients.

RESULTS

HPeV was detected in 11 and EV in 17 patients. HPeV was detected during July-September. HPeV patients, compared with EV patients, had lower age (32 vs 47 days; P = n.s.), higher prevalence of exclusive breast-feeding (81.8 vs 29.4%; P = 0.024), and lower prevalence of sick contacts (36.4 vs 88.2%; P = 0.010). More HPeV than EV patients met the systemic inflammatory response syndrome criteria (90.9 vs 52.9%; P = 0.049). In the HPeV group, leukopenia, thrombopenia, and elevated deviation enzyme were observed, although the prevalence of abnormal cerebrospinal fluid was significantly lower than in the EV group. HPeV patients had longer hospital stay (7 vs 5 days; P = 0.025).

CONCLUSION

HPeV and EV are important causal viruses of FWS. Characteristic clinical pictures exist in these virus infections, but further research is needed to accumulate more cases to produce a comprehensive picture of these virus infections.

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.

Interference of Vaccine Derived Polio Viruses with Diagnosis of Enteroviral Diseases in Neonatal Period

INTRODUCTION

Enteroviruses (EV) are a common cause of neonatal sepsis especially at the junction of summer and fall.

AIM

This study was planned to find the frequency of Enteroviral (EV) sepsis among neonates with clinical sepsis.

MATERIALS AND METHODS

This is a prospective descriptive study. Rectal and pharyngeal swab samples were taken from all neonates with clinical sepsis and a control group of neonates with simple jaundice. EV was confirmed by both cell culture and RT-PCR. Anti polio antiserum was used to differentiate Polioviruses from Non Polio EVs (NPEV).

RESULTS

We had 67 neonates with clinical sepsis and 31 cases of simple jaundice during 105 days. NPEVs were isolated from 2 cases (2.9%) of the sepsis arm and one neonate (3.2%) of the jaundice group. Polio virus was isolated from 16.2% and 15.3% of OPV recipients in the sepsis and jaundice group respectively.

CONCLUSION

Enteroviruses were not a common cause for neonatal sepsis in Nemazi hospital at the time of this study. OPV vaccinated neonates commonly pass the vaccine virus in their pharynx and stool which can be mistaken with NPEV.

Enterovirus infection in febrile neonates: A hospital-based prospective cohort study

AIM

This study aims to investigate clinical characteristics and microbiological results and to assess the predictors for enterovirus infection in febrile neonates.

METHODS

A prospective cohort study was conducted on 334 febrile patients (age: 0.33-28 days) in 2011-2012 years. Enterovirus RNA was detected by reverse transcription polymerase chain reaction on faeces or cerebrospinal fluid (CSF). Clinical characteristics were compared, and non-conditional logistic regression analysis was performed to determine independent predictors for enterovirus infection.

RESULTS

There were 131 episodes of neonatal enterovirus infection (39.22%). Forty-eight (36.64%) developed respiratory symptoms, 69 (52.67%) had diarrhoea, 22 (16.79%) had poor feeding and 34 (25.95%) had rash. Eighteen (13.74%) had lower platelet counts, and CSF specimens were positive for enterovirus RNA in 44.27% (58/131) whose CSF revealed a mean white blood cell counts of 100.38 ± 147.97 cells/mm(3) (range: 2-668 cells/mm(3) ). The positivity of stool 38.92% (130/334) was significantly higher than that of CSF specimens 26.24% (58/221) for enterovirus RNA (P < 0.01). By logistic regression analysis, the following independently predicted enterovirus infection: abnormal CSF test (odds ratio (OR): 12.426, 95% confidence interval (CI): 5.633-27.413), thrombocytopenia (OR: 3.647, 95% CI: 1.312-10.136), duration of fever >3.25 (d) (OR: 2.293, 95% CI: 1.279-4.113), highest temperature >38.35 (°C) (OR: 2.094, 95% CI: 1.342-4.123) and negative bacterial culture (OR: 5.073, 95% CI: 1.504-17.114).

CONCLUSIONS

Our data indicated that enteroviruses should be routinely considered in the differential diagnosis of febrile neonates. The factors, which may predict the risk of neonatal enterovirus infection, were abnormal CSF test, thrombocytopenia, duration of fever >3.25 (d), highest temperature >38.35 (°C) and negative bacterial culture.

Severe Enterovirus Infections in Hospitalized Children in the South of England: Clinical Phenotypes and Causative Genotypes

BACKGROUND

Most enterovirus surveillance studies lack detailed clinical data, which limits their clinical usefulness. This study aimed to describe the clinical spectrum and outcome of severe enterovirus infections in children, and to determine whether there are associations between causative enterovirus genotypes and clinical phenotypes.

METHODS

Retrospective analysis of microbiological and clinical data from a tertiary children's hospital in the South of England over a 17-month period (2012-2013).

RESULTS

In total, 30 patients were identified, comprising sepsis (n = 9), myocarditis (n = 8), meningitis (n = 8) and encephalitis (n = 5). Cases with sepsis or myocarditis were significantly younger than those with central nervous system disease (median age 21 and 15 days vs. 79 days; P = 0.0244 and P = 0.0310, respectively). There was considerable diversity in the causative genotypes in each of the clinical phenotypes, with some predominance of echoviruses in the meningitis group, and coxsackie B viruses in the myocarditis group. Thirteen cases required mechanical ventilation, 11 cases inotropic support, 3 cases dialysis and 3 cases extracorporal membrane oxygenation. The overall mortality was 10% (sepsis group, n = 1; myocarditis group, n = 2). Of the survivors, 5 (19%) had long-term sequelae (myocardial dysfunction, n = 2; neurological sequelae, n = 3). Patients with encephalitis had the longest hospital stay (median: 16 days), compared with 9, 6 and 3 days in patients with myocarditis, sepsis and meningitis, respectively (P = 0.005).

CONCLUSIONS

Enterovirus infections, particularly enteroviral myocarditis and encephalitis, can cause significant morbidity and mortality. The results show that there are currently no strong associations between clinical phenotypes and particular causative enterovirus genotypes in the South of England.

Enterovirus infections in hospitals of Ile de France region over 2013

BACKGROUND

The monitoring and genotyping of Enterovirus (EV) infections can help to associate particular or severe clinical manifestations with specific EV types and to identify the aetiology of infectious outbreaks.

OBJECTIVES

To describe the epidemiological features of EV infections diagnosed during the year 2013 in the Greater Paris area (Ile de France).

STUDY DESIGN

During 2013, 2497 samples taken from 470 patients in 33 hospitals of Ile-de France were tested for EV genome by RT-PCR. EV genotyping was performed by the National Reference Centre (NRC) laboratories. EV infections were retrospectively reviewed by retrieving clinical and genotyping data from the NRC database.

RESULTS

Of the 2497 samples, 490 (19.6%) was positive for EV genome detection. These EV infections represented 88.7% and 24.1%, respectively, of all reported regional and national infections. Twenty-seven different genotypes were identified. Echovirus 30 (E-30) accounted for 54.1% of all characterized strains and caused a large outbreak. Four severe neonatal infections were reported, of which two were caused by EV-A71. Respiratory infections involving EV-D68 were observed in two adults. One fatal case of Coxsackievirus A2-associated myocarditis was reported.

CONCLUSION

Monitoring EV infections in combination with EV genotyping via the French EV network characterized the epidemiology of EV infections in the Ile de France region in 2013 and documented severe EV infections associated with EV-A71 or CV-A2.

[Children less than 3 months hospitalised due to acute febrile syndrome. 5 years clinical experience]

INTRODUCTION

Acute fever of unknown origin (AFUO) is established when the anamnesis and physical examination cannot identify the cause. In infants less than 3 months-old this is situation for concern, due to the risk of a serious bacterial infection.

OBJECTIVE

To describe the clinical and laboratory variable of patients with AFUO, in order to look for clues in order to base studies on the decisions arising drom this problem.

PATIENTS AND METHODS

A report is presented on a retrospective study conducted on a cohort of children less than three months-old admitted to the Hospital Roberto del Río (2007-2011) due to an AFUO. Clinical histories were reviewed and the patients were grouped, according to the severity of the admission diagnosis, into severe and non-severe. They were compared in strata determined by the variables of clinical interest.

RESULTADOS

A total of 550 children were admitted with AFUO during the study period. There was low agreement between the severity on admission and at discharge (kappa=0.079; P=.26). There were 23.8% of children in the severe group and 76.2% in the non-severe group. Urinary tract infection predominated in the severe group (68.7%) and 40.7% with acute febrile syndrome in the non-severe group. The cut-off levels for C-reactive protein, white cells, and neutrophils per mm(3), to calculate the fixed and variable indices, only showed negative predictive values of some use for ruling out serious bacterial infection. The ROC curves with white cell and neutrophil counts and C-reactive protein, did not provide andy fixed indices of clinical use. More than one-third (34.6%) of lumbar punctures were traumatic or failures.

CONCLUSIONS

According to the results of this study, there is an obvious excess of hospital admissions, little usefulness in the examinations to identify serious bacterial infection, a high percentage lumbar punctures traumatic and lumbar punctures failures, and an excess of antibiotic treatments. A review of clinical criteria and procedures is needed.

Enterovirus infections are associated with white matter damage in neonates

AIM

To explore the imaging findings of neonatal infants infected with enteroviruses.

METHODS

A retrospective study was conducted on 12 patients who were diagnosed with encephalitis caused by enterovirus. Clinical presentation, cranial ultrasonography (cUS), magnetic resonance imaging (MRI) findings and neurodevelopment outcome of 12 cases were analysed.

RESULTS

Twelve infants, with a gestational age of 35 to 39 weeks, presented at 36 to 41 weeks postmenstrual age with clinical symptoms of enterovirus infections. Ten of 12 neonatal infants had a fever and 4 of 12 presented with a sepsis-like illness. cUS in one preterm infant showed periventricular echogenicity. Neonatal MRI confirmed white matter changes in 12 infants. Follow-up of infants were 18 months. Outcome was variable with cerebral palsy in 2 infants and normal neurodevelopment outcome in 10 infants.

CONCLUSIONS

Enterovirus may cause severe central nervous system infection in the neonatal period. The neuroimaging studies are informative and should be a part of care for infants with enteroviruses.

[Value of polymerase chain reaction in serum for the diagnosis of enteroviral meningitis]

Enteroviruses (EV) are a common cause of aseptic meningitis in children. Virological diagnosis of EV meningitis is currently based on the detection of the viral genome in the cerebrospinal fluid (CSF). This study attempted to determine the correlation and the temporality of the polymerase chain reaction (PCR) assay in serum and CSF and to evaluate the possibility of diagnosing EV infection only on the serum PCR. The EV genome was sought by RT real-time PCR (Smart Cycler EV Primer and Probe Set(®), Cepheid) in CSF and serum, collected at the same time, for all children who underwent a lumbar puncture for suspected meningitis, between 1 June and 31 July 2010 at the Versailles Hospital. Forty-four patients were included in the study. EV infection was documented for 22 of them. In 10 patients, the EV genome was detected in CSF only; in 3 patients in serum only, and in 9 patients in both. Among patients with acute EV neurological infection, viremic children were significantly younger (1.6 months versus 5.8 years; P<0.001). Viremia was detected when the serum was sampled within 30 h after the beginning of symptoms. These results confirm previous reports of early and transient viremia in young children. This preliminary study shows the limits and added value of EV PCR in serum. It suggests that in some children and under certain conditions (age >3 months, clinical and biological compatibility with a viral infection, no previous antibiotic therapy, time from symptom onset to blood sampling <30 h, PCR in serum analyzed within 3h), PCR in serum, when positive, is a possible alternative. Therefore, it may be possible to diagnose EV infection without performing a lumbar puncture in a limited number of young children (11.4% of our suspected cases). This study needs to be reinforced by a multicenter study with a broader panel of patients.

Enterovirus reverse transcriptase polymerase chain reaction assay in cerebrospinal fluid: an essential tool in meningitis management in childhood

BACKGROUND

Enteroviruses (EV) are the main aetiological agents of aseptic meningitis in children and a common cause of febrile illnesses in young infants in summer. A rapid diagnosis is essential to rule out other conditions. Real-time reverse transcriptase polymerase chain reaction (RT-PCR) assay performed in cerebrospinal fluid (CSF) has proved to be a very fast and useful tool.

METHODS

We collected demographic, clinical and laboratory data of children (aged 11-years or younger) with EV RT-PCR (Cepheid(®) Xpert EV) positive in CSF from December 2007 to July 2010, to describe EV meningitis in children and to determine the role of this assay.

RESULTS

We included 92 children (mean age 2.5 years), 32% of whom were neonates. There was no pleocytosis in the CSF of 18.5% (36% in newborn) of the patients, and 23 (25%) were discharged to home from the Emergency Room after the positive results. Length of hospital stay was 2 days (>2 years) versus 4.5 days in newborns (P<0.0001). Antibiotic treatment was prescribed in 38% (75% <3 months), but in 40% of these, it was stopped after the positive results. Mean EV RT-PCR information time was 7h (4-18h). All children had a good clinical outcome.

CONCLUSIONS

EV RT-PCR assay in CSF has played an essential role in the management of children with EV meningitis, allowing earlier discharges and decreasing avoidable inappropriate antibiotic treatments. This test should be considered as part of the initial study of children with aseptic meningitis, especially during epidemic seasons.

[Enterovirus nosocomial infections in a neonatal care unit: from diagnosis to evidence, from a clinical observation of a central nervous system infection]

Although enteroviruses generally cause asymptomatic or mild disease, neonates are at higher risk for severe illnesses, among which systemic disease characterized by multiorgan involvement is a potentially fatal condition. Enterovirus neonatal infections may be the source of nosocomial infections in neonatology or in pediatric intensive care units. We report central nervous system infections due to Echovirus 11 in two neonates and the molecular evidence of nosocomial transmission of this strain in a neonatal unit by enterovirus genotyping and phylogenetic analysis. This report illustrates the importance of including enterovirus genome detection in the sepsis screening concomitantly with bacteriological investigations performed at admission of a neonate. Rapid diagnosis and subsequent genotyping could have a beneficial impact on clinical practices at the individual level (reducing the length of antibiotic therapy) and public health policy at the collective level by reinforcing hygiene measures to prevent nosocomial infections, with nurseries and neonatal units being at greater risks.

Costs and infant outcomes after implementation of a care process model for febrile infants

OBJECTIVE

Febrile infants in the first 90 days may have life-threatening serious bacterial infection (SBI). Well-appearing febrile infants with SBI cannot be distinguished from those without by examination alone. Variation in care resulting in both undertreatment and overtreatment is common.

METHODS

We developed and implemented an evidence-based care process model (EB-CPM) for the management of well-appearing febrile infants in the Intermountain Healthcare System. We report an observational study describing changes in (1) care delivery, (2) outcomes of febrile infants, and (3) costs before and after implementation of the EB-CPM in a children's hospital and in regional medical centers.

RESULTS

From 2004 through 2009, 8044 infants had 8431 febrile episodes, resulting in medical evaluation. After implementation of the EB-CPM in 2008, infants in all facilities were more likely to receive evidence-based care including appropriate diagnostic testing, determination of risk for SBI, antibiotic selection, decreased antibiotic duration, and shorter hospital stays (P < .001 for all). In addition, more infants had a definitive diagnosis of urinary tract infection or viral illness (P < .001 for both). Infant outcomes improved with more admitted infants positive for SBI (P = .011), and infants at low risk for SBI were more often managed without antibiotics (P < .001). Although hospital admissions were shortened by 27%, there were no cases of missed SBI. Health Care costs were also reduced, with the mean cost per admitted infant decreasing from $7178 in 2007 to $5979 in 2009 (-17%, P < .001).

CONCLUSIONS

The EB-CPM increased evidence-based care in all facilities. Infant outcomes improved and costs were reduced, substantially improving value.

Comparison of human parechovirus and enterovirus detection frequencies in cerebrospinal fluid samples collected over a 5-year period in edinburgh: HPeV type 3 identified as the most common picornavirus type

Human enteroviruses (EVs) and more recently parechoviruses (HPeVs) have been identified as the principal viral causes of neonatal sepsis-like disease and meningitis. The relative frequencies of specific EV and HPeV types were determined over a 5-year surveillance period using highly sensitive EV and HPeV PCR assays for screening 4,168 cerebrospinal fluid (CSF) specimens collected from hospitalized individuals between 2005 and 2010 in Edinburgh. Positive CSF samples were typed by sequencing of VP1. From the 201 EV and 31 HPeV positive (uncultured) CSF samples on screening, a high proportion of available samples could be directly typed (176/182, 97%). Highest frequencies of EV infections occurred in young adults (n = 43; 8.6%) although a remarkably high proportion of positive samples (n = 98; 46%) were obtained from young infants (<3 months). HPeV infections were seen exclusively in children under the age of 3 months (31/1,105; 2.8%), and confined to spring on even-numbered years (22% in March 2006, 25% in April 2008, and 22% in March 2010). In contrast, EV infections were distributed widely across the years. Twenty different EV serotypes were detected; E9, E6, and CAV9 being found most frequently, whereas all but one HPeVs were type 3. Over this period, HPeV3 was identified as the most prevalent picornavirus type in CNS-related infections with similarly high incidences of EV infection frequencies in very young children. The highly sensitive virus typing methods applied in this study will assist further EV and HPeV screening of sepsis and meningitis cases as well as in future molecular epidemiological studies and population surveillance.

Human parechoviruses in infants with systemic infection

Human parechoviruses (HPeVs) are RNA viruses related to neonatal sepsis, meningoencephalitis and other infections in young children. Little clinical and epidemiological information is available on these viruses. HPeVs were sought in cerebrospinal fluid from 397 infants aged less than 12 months from whom a sample was obtained to exclude meningitis or encephalitis from 2006 to 2009. HPeV infections were also tested in stool samples from 271 children aged less than 3 years old with gastroenteritis from November 2008 to March 2009. HPeV detection was by real-time polymerase chain reaction assay (region 5'UTR), followed by genotyping (region VP3/VP1). HPeVs were detected in the cerebrospinal fluid of nine infants (2.3%), one aged 6 months and eight aged 14-55 days old. All were admitted to hospital for febrile syndrome with abrupt clinical deterioration and suspected systemic infection without clear laboratory signs of meningeal inflammation. The same virus was detected in all the available nasopharyngeal aspirates, stool, and/or serum samples from each patient. At least eight of the nine cases were caused by HPeV3. HPeVs were detected in stool samples from 17 children (6.3%), the most prevalent types being types 1 and 3. In conclusion, HPeV infection is common in the Basque Country (Spain) and HPeV3 is a significant cause of hospital admission due to systemic infection in the first few months of life. In these patients, HPeVs should be investigated as part of routine tests for enterovirus.

Clinical characteristics of human parechoviruses 4-6 infections in young children

BACKGROUND

Human parechoviruses (HPeVs) and enteroviruses (EVs) belong to the family Picornaviridae. EVs are known to cause a wide range of disease such as meningitis, encephalitis, and sepsis. HPeV1 and 2 have been associated with mild gastrointestinal or respiratory symptoms in young children. HPeV3 is associated with more severe neonatal infection. Little is known about the epidemiology and pathology of HPeV4-6 in children.

METHODS

We evaluated the clinical symptoms of the children with an HPeV 4, 5, or 6 infection. The patients with positive HPeV4-6 in stool samples were selected and available plasma or cerebrospinal fluid samples from these patients were tested for HPeV. Data on clinical symptoms, diagnosis, presence and duration of fever, medical history, mean age, use of antibiotics of the children infected with HPeV4-6 were retrospectively documented.

RESULTS

HPeV4-6 were found in 31 of the 277 HPeV positive children (11%). Coinfection with EV was seen in 8 patients. Fever was seen in 13 (42%) patients. Of the HPeV4-6 positive patients, 20 of the 31 children (64%) presented with gastrointestinal complaints and 18 of 31 (58%) patients had respiratory symptoms. The mean age was 14 months, 58% of the patients had an underlying disorder such as bronchomalacia or a cardiac disorder.

CONCLUSIONS

Symptomatic HPeV4-6 infections are seen in relative young children and are associated with respiratory and/or gastrointestinal symptoms. HPeV type 4 was detected more frequently than HPeV types 5 and 6.

Seizures following picornavirus infection

PURPOSE

We demonstrate the establishment and characterization of a novel virus infection-induced seizure model in C57BL/6 mice.

METHODS

C57BL/6 mice were infected with Theiler's murine encephalomyelitis virus (TMEV) or mock infected. Mice were followed for seizures, weight change, body temperature, motor function (righting reflex, rotorod) and neurological manifestations (inflammation [perivascular cuffing], pyknotic neurons, transforming growth factor [TGF]-beta expression).

RESULTS

C57BL/6 mice are susceptible to seizures induced by TMEV infection. Approximately 50% of C57BL/6 mice develop transient afebrile seizures. Motor function and coordination are impaired in seized mice. Pyramidal neuron pyknosis and TGF-beta expression correlate with seizure activity in the hippocampus.

DISCUSSION

The characterization of this model will enable the investigation of viral and immune contributions in the central nervous system to the development of seizure disorders in humans.

Severe neonatal parechovirus infection and similarity with enterovirus infection

BACKGROUND

Enteroviruses (EV) are an important cause of neonatal disease including hepatitis, meningoencephalitis, and myocarditis that can lead to death or severe long-term sequelae. Less is known about severe neonatal infection caused by the parechoviruses (PeV) of which type 1 (PeV1) and type 2 (PeV2) were previously known as echovirus 22 and echovirus 23. They belong to the same family of Picornaviridae as the EV. Of the PeV, so far only PeV3 has been associated in 2 recent reports with severe neonatal infection including involvement of central nervous system.

METHODS

We compared the clinical signs, diagnosis, laboratory data, cerebral imaging, and neurodevelopmental outcome of 11 neonates with PeV infection with 21 infants with EV infection treated in our hospital between 1994 and 2006. The diagnosis of EV infection or PeV infection was confirmed by a positive EV and/or PeV real time-polymerase chain reaction on blood, cerebrospinal fluid, (CSF) or stool or a viral culture of stool, nasopharyngeal swab, and/or CSF.

RESULTS

The 32 infants presented with sepsis-like illness and the most frequent signs were: fever, seizures, irritability, rash, and feeding problems. All patients received antibiotic treatment. Eleven of 21 infants infected with EV and 7 of 11 infants infected with PeV were full-term. Differentiation between the infants infected with EV and PeV on the basis of fever, irritability, rash, and seizures was not possible. Myocarditis was exclusively seen in 4 patients infected by EV. Eight of 11 patients with a PeV infection had meningoencephalitis of whom only 1 infant developed pleocytosis in the CSF. Serum C-reactive protein and CSF protein values were significantly higher in infants with EV infection than in those with PeV infection. Cerebral imaging of all infants with EV or PeV cerebral infection showed mild to severe white matter abnormalities. In 1 infant with EV infection and 3 infants with PeV infection, neurodevelopmental delay occurred. Mortality and long-term sequelae were mainly associated with myocarditis in the infants who were infected with EV (4 of 21).

CONCLUSIONS

It is not possible to distinguish neonatal PeV from EV infection on the basis of clinical signs. Neonates with PeV or EV infection present with sepsis-like illness and the most frequent signs are fever, seizures, irritability, rash, and feeding problems.

Aseptic meningitis

PURPOSE OF REVIEW

To highlight some of the recent key epidemiologic and clinical diagnostic dilemmas of aseptic meningitis and to evaluate some tests that may help distinguish aseptic compared with bacterial meningitis.

RECENT FINDINGS

Enteroviruses remain the most common cause of aseptic meningitis. Certain enteroviruses (e.g. coxsackie B5, echovirus 6, 9 and 30) are more likely to cause meningitis outbreaks, while others (coxsackie A9, B3 and B4) are mostly endemic. Nucleic acid tests are more sensitive than cultures in diagnosing enteroviral infections. In centers where the turnaround time for these tests is less than 24 h, there can be substantial cost savings and avoidance of unnecessary treatment of aseptic meningitis with antibiotics. Serum and stool specimens are important adjunct samples for diagnosing enteroviral infections in children. Cerebrospinal fluid protein (> or = 0.5 g/l) and serum procalcitonin (> or = 0.5 ng/ml) appear to be useful laboratory markers for distinguishing between bacterial and aseptic meningitis in children aged 28 days to 16 years, but they have relatively low sensitivity and specificity.

SUMMARY

Enteroviruses are the major causes of aseptic meningitis. The major focus of diagnosis remains ruling out bacterial infection or confirming enteroviral etiology of infection. Properly implemented nucleic acid tests have the potential to reduce cost and unnecessary treatment.

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.

Inflammatory mediators for the diagnosis and treatment of sepsis in early infancy

Interleukin-6 (IL-6), interleukin-8 (IL-8), and procalcitonin (PCT) are important parameters in the diagnosis of sepsis and for differentiating between viral and bacterial infection in children. We compared the value of IL-6, IL-8, and PCT with C-reactive protein (CRP) in the diagnosis and treatment of late-onset sepsis among infants admitted to the neonatal intensive care unit (group I) and febrile infants admitted to general hospitals from home (group II). Group I was divided into subgroups Ia, positive blood culture (all Gram-positive cocci); Ib, negative blood culture; and Ic, controls. Group II was divided into subgroups IIa, systemic enterovirus infection, and IIb, no enterovirus infection. Enterovirus was identified by real-time (RT) polymerase chain reaction (PCR) and/or by culture in blood and cerebrospinal fluid (CSF). The positive predictive values of IL-6, IL-8, and PCT (78%, 72%, and 83%, respectively) were better than that of CRP (63%) in the diagnosis of neonatal sepsis. After 48 h of antibiotic treatment, IL-6 and IL-8 levels significantly decreased and PCT stabilized in clinically recovered patients, suggesting that these markers may be useful in distinguishing patients in which antibiotic treatment may be discontinued. Among infants of subgroup IIa, 80%-90% had normal values of IL-6, IL-8, and PCT, whereas CRP was increased in 40%. In conclusion, IL-6, IL-8, and PCT are better parameters than CRP in the diagnosis and follow-up of neonatal sepsis due to coagulase-negative staphylococci (CoNS) and in the exclusion of bacterial infection among those with enteroviral infection among febrile infants presenting from home.

Real-time PCR in clinical microbiology: applications for routine laboratory testing

Real-time PCR has revolutionized the way clinical microbiology laboratories diagnose many human microbial infections. This testing method combines PCR chemistry with fluorescent probe detection of amplified product in the same reaction vessel. In general, both PCR and amplified product detection are completed in an hour or less, which is considerably faster than conventional PCR detection methods. Real-time PCR assays provide sensitivity and specificity equivalent to that of conventional PCR combined with Southern blot analysis, and since amplification and detection steps are performed in the same closed vessel, the risk of releasing amplified nucleic acids into the environment is negligible. The combination of excellent sensitivity and specificity, low contamination risk, and speed has made real-time PCR technology an appealing alternative to culture- or immunoassay-based testing methods for diagnosing many infectious diseases. This review focuses on the application of real-time PCR in the clinical microbiology laboratory.

Clinical and epidemiologic characteristics of viral infections in a neonatal intensive care unit during a 12-year period

BACKGROUND

The incidence of viral infections in patients treated in the neonatal intensive care unit (NICU) is not well-known. We summarized the data of all patients with laboratory-confirmed viral infections admitted at the NICU of our hospital during the period of 1992-2003.

OBJECTIVES

To determine the incidence of viral infections among infants hospitalized in a NICU, the associated clinical manifestations and their outcome.

METHODS

Retrospective analysis of epidemiologic, virologic and clinical data from infants with proven viral infection. The diagnosis viral infection was confirmed by positive viral culture and/or polymerase chain reaction from clinical samples.

RESULTS

Viral infection was confirmed in 51 of 5396 infants (1%) admitted to the NICU; 20 (39%) had an enterovirus and parechovirus (EV/PEV) infection, 15 (29%) a respiratory syncytial virus (RSV) infection, 5 (10%) a rotavirus infection, 3 (6%) a cytomegalovirus (CMV) infection, 2 (4%) an adenovirus infection, 2 (4%) a parainfluenza virus infection, 2 (4%) a herpes simplex virus infection, 1 (2%) a rhinovirus infection and 1 (2%) a rubella virus infection. Three of the infants presented at birth with symptomatic rubella virus, CMV or herpes simplex virus infection. RSV infection developed mostly in hospitalized infants (60%), and 93% of infections occurred during the winter (November-March). The clinical presentations of EV/PEV disease were sepsis-like illness, prolonged seizures in term infants and gastrointestinal disease in preterm infants. RSV, parainfluenza virus, rhinovirus and CMV caused respiratory disease, predominantly in preterm infants. Gastrointestinal disease was seen only in preterm infants with adenovirus, rotavirus or EV/PEV infection. Mortality and serious sequelae were high in patients infected with EV/PEV (10 and 15%, respectively).

CONCLUSIONS

The incidence of viral infection in the NICU was 1%. Enteroviral infections were the most frequently diagnosed infections, occurred often in term infants born at home and presented with sepsis-like illness or seizures. Preterm infants hospitalized from birth mainly developed gastrointestinal disease caused by rotavirus and adenovirus infection or respiratory disease caused by RSV, parainfluenza and CMV infection. Enteroviruses were responsible for the highest mortality and development of serious sequelae.

Diagnosis and outcomes of enterovirus infections in young infants

BACKGROUND

Enterovirus (EV) infections commonly cause fever in infants younger than 90 days of age. The polymerase chain reaction (PCR) has improved our ability to diagnose EV infections.

OBJECTIVE

To evaluate the utility of blood and cerebrospinal fluid (CSF) specimens for the diagnosis of EV infections by PCR and to describe a large cohort of EV-infected infants.

DESIGN/METHODS

Febrile infants younger than 90 days of age evaluated for sepsis at Primary Children's Medical Center in Salt Lake City, UT, were enrolled in a prospective study designed to identify viral infections from December 1996 to June 2002. All patients had bacterial cultures of blood, urine and CSF. Testing for EV was performed by PCR and/or viral cultures. Patients who were positive for EV were identified for this study.

RESULTS

Of 1779 febrile infants enrolled, 1061 had EV testing and 214 (20%) were EV-positive. EV infections were diagnosed by PCR of blood, CSF or both in 93% of infants. PCR testing was positive in blood in 57%, and blood was the only positive specimen for 22% of EV infected infants. PCR of CSF was positive in 74%. The mean age of infants with EV infection was 33 days, with 18% younger than 14 days and 5% younger than 7 days. Fifty percent of EV-positive infants had CSF pleocytosis. Of EV PCR-positive infants, 91% were admitted, and 2% required intensive care. Possible serious EV disease was diagnosed in <1%, and there were no deaths. Twelve infants (5.6%) had concomitant urinary tract infection, and 3 (1%) had bacteremia.

CONCLUSIONS

EV infections are common in febrile infants younger than 90 days. Blood and CSF are equally likely to yield positive results by PCR, but the combination of both specimens improved the diagnostic yield.

Retrospective review of serious bacterial infections in infants who are 0 to 36 months of age and have influenza A infection

OBJECTIVE

Previous studies of febrile children who were 3 to 36 months of age and had clinically recognizable viral syndromes have shown low rates of concurrent bacteremia. We sought to determine the prevalence of serious bacterial infections (SBIs) among children with influenza A, a viral syndrome that can be established definitively by specific tests.

METHODS

We performed a retrospective cross-sectional study of patients who were 0 to 36 months of age and presented with fever to the emergency department (ED) over 4 consecutive influenza seasons. Chest radiographs and urine and cerebrospinal fluid cultures also were reviewed.

RESULTS

Of 705 included patients, 163 (23%) were influenza positive (IP) and 542 (77%) were influenza negative (IN). Only 1 IP patient was bacteremic (0.6%) versus 23 of the 542 IN control subjects (4.2%). Two (1.8%) of 110 IP cases had urinary tract infections versus 38 (9.9%) of the 382 IN control subjects. Thirteen (25.4%) of 51 IP patients had radiographic evidence of pneumonia versus 99 (41.9%) of 236 IN control subjects. There were no cases of meningitis in 41 cerebrospinal fluid samples obtained from IP patients versus 4 (2.2%) cases of culture-positive meningitis in 179 IN control subjects. A total of 16 (9.8%) SBIs were identified in the IP cases versus 153 (28.2%) in the IN control subjects.

CONCLUSIONS

Febrile children with influenza A had a lower prevalence of bacteremia, urinary tract infections, consolidative pneumonia, or any SBI compared with those without influenza A infection in this study.

Factors influencing PCR detection of viruses in cerebrospinal fluid of patients with suspected CNS infections

BACKGROUND

Polymerase chain reaction (PCR) is used to detect viruses in the cerebrospinal fluid (CSF) of patients with neurological disease. However, data to assist its use or interpretation are limited.

OBJECTIVE

We investigated factors possibly influencing viral detection in CSF by PCR, which will also help clinicians interpret positive and negative results.

METHODS

CSF from patients with was tested for human herpesviruses types 1-6, JC virus, enteroviruses, and Toxoplasma gondii. The likelihood of central nervous system (CNS) infection was classified as likely, possible, or unlikely. PCR findings in these categories were compared using single variable and logistic regression analysis.

RESULTS

Of 787 samples tested, 97 (12%) were PCR positive for one or more viruses. Of episodes likely to be CNS viral infections, 30% were PCR positive compared to 5% categorised as unlikely. The most frequent positive findings were Epstein Barr virus (EBV), enteroviruses, and herpes simplex virus (HSV). Enteroviruses and HSV were found predominantly in the likely CNS viral infection group, whereas EBV was found mainly in the unlikely group. Positive PCR results were more likely when there were 3-14 days between symptom onset and lumbar puncture, and when CSF white cell count was abnormal, although a normal CSF did not exclude a viral infection.

CONCLUSIONS

The diagnostic yield of PCR can be maximised by using sensitive assays to detect a range of pathogens in appropriately timed CSF samples. PCR results, in particular EBV, should be interpreted cautiously when symptoms cannot readily be attributed to the virus detected.

Serious bacterial infections in febrile infants 1 to 90 days old with and without viral infections

OBJECTIVE

The risk of serious bacterial infection (SBI) in febrile infants who are classified as low risk (LR) or high risk (HR) by the Rochester criteria has been established. LR infants average a 1.4% occurrence of SBI, whereas HR infants have an occurrence of 21%. The occurrence of SBI in Rochester LR or HR infants with confirmed viral infections is unknown. The objective of this study was to determine the occurrence of SBI in Rochester LR and HR infants with and without viral infections.

METHODS

All febrile infants who were 90 days or younger and evaluated at Primary Children's Medical Center between December 1996 and June 2002 were eligible. Infants were classified as Rochester LR or HR, and discharge diagnoses were collected. Viral testing for enteroviruses, respiratory viruses, rotavirus, and herpesvirus was performed as indicated by study protocol, clinical presentation, and season of the year. Results of all bacterial cultures were reviewed.

RESULTS

Of 1779 infants enrolled, 1385 (78%) had some form of viral diagnostic testing and 491 (35%) had 1 or more viruses identified. By the Rochester criteria, 456 (33%) infants were classified as LR and 922 (67%) infants as HR. For infants with viral infections, the occurrence of SBI was significantly lower than in infants without a viral infection (4.2% vs 12.3%). Rochester HR virus-positive (HR+) infants had significantly fewer bacterial infections than HR virus-negative (HR-) infants (5.5% vs 16.7%). When compared with HR- infants, HR+ infants were less likely to have bacteremia, urinary tract infection, or soft tissue infections, and HR+ infants had a similar occurrence of bacteremia as LR infants (0.92% vs 1.97%).

CONCLUSIONS

Febrile infants with confirmed viral infections are at lower risk for SBI than those in whom a viral infection is not identified. Viral diagnostic data can positively contribute to the management of febrile infants, especially those who are classified as HR.

Neonatal coxsackie B virus infection-a treatable disease?

Ten neonates with coxsackie B viral infection presented over a 3-month period. Clinical features included meningoencephalitis, thrombocytopenia, disseminated intravascular coagulopathy, cardiomyopathy, and hepatitis. Eight infants had multiorgan disease, four with severe myocardial dysfunction, of whom two died. All of the infants with severe disease developed symptoms within 7 days of age. In infants presenting within 10 days of birth, in all cases there were symptoms compatible with maternal infection prior to delivery. Severity was associated with perinatal transmission. Enteroviral polymerase chain reaction of CSF, urine, stool or throat swab was positive in nine of the ten babies. Seven of the infants were treated with a 7-day course of the new anti-picornaviral drug pleconaril (5 mg/kg 3 times daily).

CONCLUSION

These cases highlight the importance of not missing coxsackie B viral infection in the differential diagnosis of the septic neonate, especially as there is now a potential treatment.