Diagnosis of enteroviral meningitis with the polymerase chain reaction

Activity- and gene-based quantification of enteric viruses, F- specific RNA phage genogroups, pepper mild mottle virus, and Escherichia coli in surface water

Polymerase chain reaction (PCR) is widely applied for the monitoring of pathogenic viruses in water environments. To date, several pretreatments to selectively detect genes from infectious viruses via PCR have been developed. This study was aimed to characterize and validate methods for quantifying active viruses and indicators and to evaluate the proportion of their active fractions in surface water (n = 42). Active E. coli and F-specific RNA phage (FRNAPH) genogroups were quantified using culture assays. In addition to these microbes, norovirus genogroups I (GI) and II, Aichi virus 1, and pepper mild mottle virus (PMMoV) were quantified by (reverse transcription)-quantitative PCR (RT-qPCR) with and without cis-dichlorodiammineplatinum (CDDP) treatment to exclude genes in inactive viruses. CDDP-RT-qPCR showed concentrations and detection frequencies comparable to or higher than culture assays. Consequently, although CDDP-RT-qPCR can suggest the presence of an inactive virus, it can also overestimate the activity of the virus in the environment. Differences between culture and CDDP-RT-qPCR and between CDDP-RT-qPCR and RT-qPCR varied among the viruses. CDDP-RT-qPCR showed a concentration comparable to the culture assay (within 1 log10 difference) in 93 % of positive samples for GI-FRNAPH but in <63 % of positive samples for GII- and GIII-FRNAPHs. GII-NoV was detected from 5 and 30 out of 42 samples via CDDP-RT-qPCR and RT-qPCR, respectively, and was suggested as inactivated by 2.0 log10 or higher in most of the samples. By contrast, concentrations of PMMoV determined by these two assays were not notably different. It is suggested that the operational conditions of wastewater treatment plants around the sites, rather than environmental stresses, affected the microbial inactivation. To better understand the infectivity of viruses in the environment, it is important to investigate them using sensitive detection methods at various sites, including the source of contamination.

Molecular diagnostics of infectious disease: Detection and characterization of microbial agents in cytology samples

BACKGROUND

Cytology samples are widely used to diagnose various infectious diseases by detection and identification of causative infectious agents, including bacteria, fungi, and viruses. The role of cytopathology in infectious disease has expanded tremendously in the past decades with the advances in molecular techniques. Molecular diagnostic methods, compared to conventional methods, have shown improved patient outcome, reduction in cost, and shortened hospital stay times. The aim of this article is to review molecular testing in cytology samples for diagnosis of infectious diseases.

METHODS

The literature search for molecular testing in common cytology samples for diagnosis of infectious diseases was performed. The findings of the studies were summarized. The common cytology samples included in this article were gynecologic specimens, cerebrospinal fluid, bronchoalveolar lavage, and urine samples.

CONCLUSIONS

There are a number of molecular diagnostic tests that are available to be used in common cytology samples to detect infectious agents. Each test has its own advantages and limitations. It is our hope that upon reading this review article, the readers will have better understanding of molecular diagnostic testing of infectious diseases utilizing commonly sampled cytology specimens in daily practice.

Hearing and Neurodevelopmental Outcomes of Young Infants with Parechovirus-A and Enterovirus Meningitis: Cohort Study in Singapore Children and Literature Review

Parechovirus-A (PeV-A) and Enterovirus (EV) commonly cause childhood aseptic meningitis. Bacterial meningitis in children has been associated with devastating long-term sequelae. However, developmental outcomes are unclear in Parechovirus meningitis. This study aims to review the clinical findings and developmental outcomes of infants with PeV-A and EV meningitis. We performed a retrospective study of infants aged 90 days or younger being admitted to our hospital with PeV-A meningitis between November 2015 and July 2017, with positive cerebrospinal fluid (CSF) PeV-A PCR and negative blood and CSF bacterial cultures. Hearing and neurodevelopmental outcomes were compared with a previous cohort of infants aged 90 days or younger with EV meningitis admitted from January 2015 to December 2015. A total of 161 infants were included in our study, of which 68 infants (42.2%) had PeV-A meningitis and 93 infants (57.8%) had EV meningitis. We assessed their developmental outcome at 6 months, 1 year, and 2 years post-meningitis. At 2 years post-meningitis, three infants with PeV-A meningitis had developmental delay (5.5%), whereas none with EV meningitis had developmental delay. One patient had speech delay and autism spectrum disorder, while two had mild speech delay. When compared with our cohort of EV meningitis ≤90 days old, children with PeV-A meningitis ≤90 days old were more likely to have developmental delay 2 years post-meningitis (odds ratio 2.4, 95% confidence interval 2.0–3.0, p = 0.043). None of the patients with PeV-A or EV meningitis had sensorineural hearing loss or neurological sequelae, such as cortical blindness, oropharyngeal dysphagia, hydrocephalus, epilepsy, or cerebral palsy. Infants with PeV-A meningitis had a significant risk of developmental delay 2 years post-meningitis compared with those with EV meningitis. It is important to follow-up the developmental milestones of infants diagnosed with PeV-A meningitis for at least 2 years; and when they develop developmental delay, to ensure that they receive appropriate intervention.

Good hearing outcome in children recovering from non-polio enteroviral meningitis

AIM

Evaluation of hearing outcome in children following non-polio enteroviral meningitis (EVM).

METHODS

We reviewed hearing outcome of children, aged ≤15 years, with EVM managed at our institution over a 4-year period from July 2008 to July 2011 and January-December 2015. Children with concomitant bacterial infections, and those who required intensive care, or with a prior history of hearing impairment or immunodeficiency were excluded. Data on demographics, medical history, presentation and outcome of hearing screen were collected. The children attended post-meningitis review and hearing screen utilising transient-evoked otoacoustic emission testing at 8-10 weeks. Children who failed the transient-evoked otoacoustic emission testing and those with caregiver concerns were referred to otolaryngology for comprehensive audiologic evaluation.

RESULTS

The study cohort consisted of 179 children, aged from 3 days to 15 years, of whom 158 (89%) were younger than 90 days of age. Eleven were preterm infants. A total of 158 children had received intravenous gentamicin at 5-7.5 mg/kg/day for a median duration of 2 days. All 179 study participants were found to have good hearing post EVM.

CONCLUSION

Hearing outcome in children recovering from EVM is good.

Molecular Microbiology

Background

Nucleic acid (NA) amplification techniques are now commonly used to diagnose and manage patients with infectious diseases. The growth in the number of Food and Drug Administration–approved test kits and analyte-specific reagents has facilitated the use of this technology in clinical laboratories. Technological advances in NA amplification techniques, automation, NA sequencing, and multiplex analysis have reinvigorated the field and created new opportunities for growth. Simple, sample-in, answer-out molecular test systems are now widely available that can be deployed in a variety of laboratory and clinical settings. Molecular microbiology remains the leading area in molecular pathology in terms of both the numbers of tests performed and clinical relevance. NA-based tests have reduced the dependency of the clinical microbiology laboratory on more traditional antigen detection and culture methods and created new opportunities for the laboratory to impact patient care.

Content

This chapter reviews NA testing as it applies to specific pathogens or infectious disease syndromes, with a focus on those diseases for which NA testing is now considered the standard of care and highlights the unique challenges and opportunities that these tests present for clinical laboratories.

Enteroviral encephalitis in children: clinical features, pathophysiology, and treatment advances

Enteroviruses (EVs) have emerged as one of the important etiological agents as a causative organism for encephalitis, especially in children and adults. After the first report of EV encephalitis cases in 1950s, there have been increasing reports of regular outbreaks of EV encephalitis worldwide. Enteroviruses are RNA viruses of the family Picornaviridae that consists of more than 100 serotypes, which are characterized by a single positive-strand genomic RNA. The clinical features are pleomorphic and can be accompanied by mucocutaneous manifestations or isolated encephalitis only. The incidence of encephalitis in EV infection is reported to be about 3% and is associated with high mortality and morbidity. A number of newer therapeutic agents have been used in EV encephalitis with variable results. This review will focus on clinical features, pathophysiology, and newer treatment modality in EV encephalitis.

Nonpolio enterovirus infections in neonates

There are currently 12 species and over 100 serotypes that have been identified in the enterovirus genus, including the coxsackieviruses, echoviruses, and polioviruses. Since their discovery 65 years ago, much has been discovered and continues to be researched regarding the pathogenicity and scope of disease of nonpolio enteroviruses. Like many infections, enteroviruses have been found to affect neonates much differently, and often more severely, than older children and adults. Neonatal infections often cause mild illnesses with nonspecific symptoms, but they may also have severe presentations involving the cardiovascular, gastrointestinal, hematologic, or central nervous systems. This article provides an overview of what is known about nonpolio enteroviruses in neonates including epidemiology, transmission, clinical presentation, diagnosis, and treatment.

Comparison of the genexpert enterovirus assay (GXEA) with real-time one step RT-PCR for the detection of enteroviral RNA in the cerebrospinal fluid of patients with meningitis

Background

Enteroviruses (EVs) are the leading cause of aseptic meningitis worldwide. Detection of enteroviral RNA in clinical specimens has been demonstrated to improve the management of patient care, especially that of neonates and young children.

Findings

To establish a sensitive and reliable assay for routine laboratory diagnosis, we compared the sensitivity and specificity of the GeneXpert Enterovirus Assay (GXEA) with that of the reverse transcription polymerase chain reaction (RT-PCR) based assay referred to as real-time one step RT-PCR (RTo-PCR). The sensitivity/specificity produced by GXEA and RTo-PCR were 100%/100% and 65%/100%, respectively.

Conclusions

Both methods evaluated in this article can be used for detection of enterovirus in clinical specimens and these nucleic acid amplification methods are useful assays for the diagnosis of enteroviral infection.

Optimization of a combined human parechovirus-enterovirus real-time reverse transcription-PCR assay and evaluation of a new parechovirus 3-specific assay for cerebrospinal fluid specimen testing

Human parechoviruses (HPeVs), particularly type 3 (HPeV3), are known central nervous system (CNS) pathogens, causing serious infections in infants similar to those caused by enteroviruses (EVs). The primary aim of this study was to combine and validate HPeV and EV real-time reverse transcription-PCR (RT-PCR) detection assays with the best available RT-PCR reagents and conditions for parallel detection of HPeV and EV on a single platform. The secondary aim was to develop and validate a newly developed HPeV3-specific real-time RT-PCR assay. Five commercially available RT-PCR kits were evaluated with the pan-HPeV and EV assays in one-step and two-step RT-PCRs. Two-step RT-PCR with the AgPath ID RT-PCR (AGP) kit performed best for both pan-HPeV and EV assays. The pan-HPeV-specific assay performed best with the AGP kit in a one-step RT-PCR. Frozen aliquots of 145 (for HPeV, n = 70; for EV, n = 75) previously characterized cerebrospinal fluid (CSF) specimens were tested by EV-, pan-HPeV-, and HPeV3-specific (HPeV specimens only) assays. The pan-HPeV and EV assays demonstrated 100% analytical sensitivity and specificity compared to historic results, while the HPeV3-specific assay demonstrated 97% sensitivity and 100% specificity. We propose a real-time pan-HPeV, EV two-step RT-PCR algorithm for simultaneous detection of HPeV and EV from CSF specimens on a single platform. The HPeV3-specific one-step RT-PCR assay can be used as a rapid and cost-effective assay to detect and identify HPeV3 in pan-HPeV RT-PCR assay-positive CSF specimens.

[Detection of enterovirus in cerebrospinal fluid by real-time nested reverse transcription polymerase chain reaction.]

BACKGROUND

Enterovirus is a common cause of aseptic meningitis, respiratory disease and nonspecific febrile illness. The conventional methods for laboratory diagnosis of enterovirus infections have been virus culture and serotyping by an immunofluorecent test. We studied a new and more rapid approach for enterovirus detection in cerebrospinal fluid (CSF) by real-time nested PCR.

METHODS

This study was performed on 50 CSF specimens from patients suspected of aseptic meningitis. Enterovirus was detected in CSF by PCRs for 3 different targets and real-time nested PCR. Enterovirus culture was also performed in 44 CSF specimens.

RESULTS

The positive rate of PCRs for each of the 3 different targets was 26.0%, 40.0%, or 46.0%, and that of real-time nested PCR was 86.0%. Only 6.8% were positive in culture. Thus, the positive rate of real-time nested PCR was much higher than other methods.

CONCLUSIONS

Our study revealed that the real-time nested PCR should be useful for diagnosis of enterovirus infections because of a high sensitivity and rapid detection.

Bovine lactoferrin digested with human gastrointestinal enzymes inhibits replication of human echovirus 5 in cell culture

Many infant formulas are enriched with lactoferrin (Lf) because of its claimed beneficial effects on health. Native bovine Lf (bLf) is known to inhibit in vitro replication of human enteroviruses, a group of pathogenic viruses that replicate in the gut as their primary infection site. On the basis of a model digestion and human gastrointestinal enzymes, we hypothesized that bLf could retain its antiviral properties against enterovirus in the gastrointestinal tract, either as an intact protein or through bioactive peptide fragments released by digestive enzymes. To test our hypothesis, bLf was digested with human gastric juice and duodenal juice in a 2-step in vitro digestion model. Two gastric pH levels and reduction conditions were used to simulate physiological conditions in adults and infants. The antiviral activity of native bLf and of the digested fractions was studied on echovirus 5 in vitro, using various assay conditions, addressing several mechanisms for replication inhibition. Both native and digested bLf fractions revealed a significant inhibitory effect, when added before or simultaneously with the virus onto the cells. Furthermore, a significant stronger sustained antiviral effect was observed when bLf was fully digested in the gastric phase with fast pH reduction to 2.5, compared with native bLf, suggesting the release of antiviral peptides from bLf during the human digestion process. In conclusion, this study demonstrates that bLf may have a role in the prevention of human gastrointestinal virus infection under physiological conditions and that food containing bLf may protect against infection in vivo.

Development of a highly sensitive real-time one step RT-PCR combined complementary locked primer technology and conjugated minor groove binder probe

Background

Enterovirus (EV) infections are commonly associated with encephalitis and meningitis. Detection of enteroviral RNA in clinical specimens has been demonstrated to improve the management of patients, by ruling out other causes of disease.

Method

To develop a sensitive and reliable assay for routine laboratory diagnosis, we developed a real-time one step reverse transcription polymerase chain reaction (RT-PCR) assay with minor groove binder probes and primers modified with complementary locked primer technology (TMC-PCR). We checked the sensitivity of the developed assay by comparing it to a previously published TaqMan probe real-time one-step RT-PCR (TTN-PCR) procedure using enteroviral isolates, Enterovirus Proficiency panels from Quality Control on Molecular Diagnostics (QCMD-2007), and clinical specimens from patients with suspected EV infections.

Results

One hundred clinical specimens from 158 suspected viral meningitis cases were determined to be positive by the TMC-PCR assay (63.29%), whereas only 60 were found to be positive by the TTN-PCR assay (37.97%). The positive and negative agreements between the TMC-PCR and TTN-PCR assays were 100% and 59.2%, respectively.

Conclusion

This data suggest that the TMC-PCR assay may be suitable for routine diagnostic screening from patient suspected EV infection.

Enterovirus infections of the central nervous system

Enteroviruses (EV) frequently infect the central nervous system (CNS) and induce neurological diseases. Although the CNS is composed of many different cell types, the spectrum of tropism for each EV is considerable. These viruses have the ability to completely shut down host translational machinery and are considered highly cytolytic, thereby causing cytopathic effects. Hence, CNS dysfunction following EV infection of neuronal or glial cells might be expected. Perhaps unexpectedly given their cytolytic nature, EVs may establish a persistent infection within the CNS, and the lasting effects on the host might be significant with unanticipated consequences. This review will describe the clinical aspects of EV-mediated disease, mechanisms of disease, determinants of tropism, immune activation within the CNS, and potential treatment regimes.

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.

Enhanced detection of enteroviruses in clinical samples by reverse transcription-PCR using complementary locked primer technology

To increase detection sensitivity, we modified primers using complementary locked primer (CLP) technology. The sensitivity of the reverse transcription-PCR (RT-PCR) with CLP-modified primers was 10- to 100-fold higher than that of RT-PCR without these primers. CLP-modified primers can increase sensitivity, providing a widely accessible method for molecular diagnosis.

GeneXpert enterovirus assay: one-year experience in a routine laboratory setting and evaluation on three proficiency panels

A prospective unblinded comparative evaluation of three assays for the detection of enteroviral RNA performed on 83 positive and 79 negative cerebrospinal fluid samples showed initial and resolved sensitivities of 90.4% and 98.8%, respectively, for the Cepheid GeneXpert enterovirus assay; 94.0% and 97.6%, respectively, for the Argene enterovirus consensus kit; and 100% and 100%, respectively, for an in-house real-time PCR. The initial and resolved specificities were 100% for all three assays.

Persistent Coxsackie B encephalitis: Report of a case and review of the literature

Although the diagnosis is rarely confirmed, enteroviruses are a common cause of meningitis. Coxsackie B is responsible for more than half of the cases of aseptic meningitis in infants less than 3 months old, but is less common as a cause of neurological disease in older persons. In addition to aseptic meningitis, Coxsackie B has been reported to cause a wide range of other neurological disorders, albeit rarely. The authors report a young adult with persistent Coxsackie B encephalitis that was heralded by focal seizures and evolved to intractable coma with multifocal myoclonus. The diagnosis was established by immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR) on tissue obtained at brain biopsy. Cerebrospinal fluid (CSF) viral cultures and PCR were negative for enteroviruses. This case highlights unusual features of a persistent infection that could easily have been mistaken for a neurodegenerative or other noninfectious process. It also emphasizes the importance of performing brain biopsy on individuals with neurological disease of obscure nature.

Enterovirus meningitis in Greece from 2003-2005: diagnosis, CSF laboratory findings, and clinical manifestations

Enteroviruses (EVs) are the most commonly identified cause of aseptic meningitis. Rapid detection and characterization of EV meningitis is essential in making decisions for patient management and treatment. A total of 52 cases of acute aseptic meningitis that occurred from March 2003 to April 2005 were investigated for EVs using viral culture and/or molecular methods directly in the cerebrospinal fluid (CSF). EVs were detected in 21 out of 52 (40.4%) patients using reverse transcription-PCR (RT-PCR) and/or tissue culture. EVs were isolated from six out of 37 (16.2%) cultured specimens, while 20 out of 52 (38.4%) specimens yielded positive results when 5'non-coding region (5'NCR) RT-PCR assay was used. One specimen that was culture-positive was RT-PCR-negative. Using the VP1-2A RT-PCR and sequence analysis, 14 of the 21 positive EVs were identified as: four strains of Coxsackie virus B5, five echovirus 11, two echovirus 9, one echovirus 5, one echovirus 14, and one Coxsackie virus A9. Fever, headache, vomiting, and stiff neck were the most pronounced symptoms. Pleocytosis with the predominance of lymphocytes and mild elevated protein levels characterized the CSF specimens. Coxsackie virus B5 and echovirus 11 were the predominant serotypes during the study period. Although there was seasonal enteroviral activity (April-November), cases also occurred in the cold months. The 5'NCR and VP1-2A RT-PCR with sequence analysis were found to be superior to conventional methods for direct diagnosis and the typing of EVs.

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.

Enterovirus meningitis in Brazil, 1998-2003

Acute viral infections of the central nervous system (CNS) such as acute flaccid paralysis, meningitis, and encephalitis, are responsible for a high morbidity, particularly in children. Non-Polio enteroviruses (NPEV) are known to be responsible for over 80% of viral meningitis in which the etiologic agent is identified. In the present study, we show the frequency of enterovirus meningitis in Brazil from December 1998 to December 2003. Enterovirus were isolated from 162 (15.8%), of a total of 1,022 cerebrospinal fluid (CSF) specimens analyzed. Echovirus 30 was identified in 139 of these isolates (139/162-85.2%). Other identified enteroviruses were: Coxsackievirus B5 (3.7%), Echovirus 13 (3.7%), Echovirus 18 (3%), Echovirus 6 (1.2%), Echovirus 25 (1.2%), Echovirus 1 (0.6%), and Echovirus 4 (0.6%). Patients's age ranged from 28 days to 68 years old. The most frequent symptoms were fever (77%), headache (69.5%), vomiting (71.3%), neck stiffness (41.3%), convulsion (7.1%), and diarrhea (3.7%). Although, the majority of the patients recovered without any complication or permanent squeal, five deaths occurred. Throughout the surveillance period, five viral meningitis outbreaks were confirmed: four in the Southern Brazil and one in the Northeast Brazil. Echovirus 30 was responsible for four out of the five outbreaks while Echovirus 13 caused the fifth one. Besides the outbreaks, 734 sporadic cases were also identified during the study period and 59 of these were positive for virus isolation (8%). Echovirus 30 accounted for 70% of the isolates. Our results showed that Echovirus 30 was the most prevalent etiological agent of viral meningitis in Brazil, causing both outbreaks and sporadic cases.

Comparative study of four extraction methods for enterovirus recovery from wastewater and sewage sludge

This study investigated four methods for the recovery of enteroviruses from sterilized raw wastewater, activated sludge, thickened sludge and treated wastewater, inoculated with Echovirus 11, Gregory prototype. The adsorption-elution method recommended by the US Environmental Protection Agency (EPA) was better for Echovirus 11 recovery than a sonication method, a modified EPA method and a membrane adsorption elution method since it resulted in the highest detection levels by cell culture and RT-PCR (Friedman's test, p<0.00041 and p=0.041, respectively).

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.

Presentation, diagnosis, and management of enterovirus infections in neonates

The nonpoliovirus enteroviruses commonly infect newborns, with consequences ranging from asymptomatic infection and benign illness, to severe, life-threatening disease. Frequently occurring symptoms include fever, irritability, lethargy, anorexia, and rash. Although most illnesses are mild, severe disease develops in a subset of newborns infected in the first 2 weeks of life. Severe disease may consist of sepsis, meningoencephalitis, myocarditis, pneumonia, hepatitis, and/or coagulopathy. Substantial mortality rates have been reported, and long-term sequelae may occur among survivors. Risk factors and clinical features associated with severe disease include absence of neutralizing antibody to the infecting serotype, maternal illness prior to or at delivery, prematurity, illness onset within the first few days of life, multiorgan disease, severe hepatitis, positive serum viral culture, and specific infecting serotype (e.g. group B coxsackieviruses and echovirus 11). Whereas the mainstay of diagnosis has traditionally been viral isolation in tissue culture, the polymerase chain reaction has been demonstrated to be more sensitive than culture, highly specific, and rapid. Immunoglobulin has been used as a therapeutic agent for neonates with enterovirus disease; however, clinical efficacy has not been proven. Specific antiviral therapy for enteroviruses is in development. Pleconaril is an investigational agent that inhibits viral attachment to host cell receptors and uncoating of viral nucleic acid. It has broad and potent anti-enterovirus activity, excellent oral bioavailability, and is well tolerated. Some clinical trials have demonstrated benefit in children and adults with enterovirus meningitis, and in adults with upper respiratory tract infections caused by picornaviruses (rhinoviruses or enteroviruses). Data summarizing compassionate use for severe enterovirus diseases (including neonatal sepsis) also suggest possible benefit. Limited pharmacokinetic data are available in infants and neonates. A multicenter, placebo-controlled, randomized trial of pleconaril in neonates with severe hepatitis, coagulopathy, and/or myocarditis is currently being conducted.

Prospective investigation of a large outbreak of meningitis due to echovirus 30 during summer 2000 in marseilles, france

Enteroviruses (EVs) are responsible for an array of clinical diseases affecting different systems of the organism. Many cases are asymptomatic; the most severe clinical syndromes caused by EVs are due to infection of the central nervous system and present as aseptic meningitis or encephalitis. We report here a large outbreak of enteroviral meningitis that spread in Marseilles, France, during the year 2000. The dominant strain of the outbreak was genetically identified as a human echovirus 30. The study was conducted prospectively from May to December 2000, with an investigative protocol recording epidemiologic, clinical, and laboratory data. A total of 250 patients with febrile neurologic manifestations were included between May 15 and December 30, 2000. A total of 195 cerebrospinal fluid (CSF) samples, 114 throat swabs, and 85 stool specimens were processed through viral culture and resulted in respectively 117 (60%), 61 (54%), and 58 (68%) cultures positive for EV; 69/106 (65%) CSF samples tested positive for the presence of EV RNA. None of the throat swab cultures but 5 of the stool cultures in control patients were positive. One hundred thirty-nine (55.6%) patients were considered confirmed cases because they had positive culture or reverse transcription polymerase chain reaction (RT-PCR) in CSF, and 38 (15.2%) patients were considered probable cases because they had a positive throat and/or stool culture and a negative (or not performed) procedure in CSF. The 177 confirmed and probable cases were not significantly different from the remaining 73 patients in terms of age distribution and epidemiologic, clinical, and biologic characteristics. The median age was 18.4 years (range, 15 d to 84 yr), and 92% of patients were younger than 40 years old. The male:female sex ratio was 1.8:1. We found no evidence of cases spread in nosocomial, household, or institutional settings, or limited community spread. All patients were immunocompetent except 4 adults. Meningoencephalitis represented 5.6% of cases. All but 3 of the 177 patients had a good outcome without sequelae. Two immunocompetent adults with meningoencephalitis had neurologic sequelae and an immunosuppressed adult had a fatal outcome. Upper respiratory symptoms were noted in 18.5% of patients, diarrhea in 11.5%, various types of rash in 4.5%, and myalgia in 3.8%. In CSF, white cell count was elevated in 90% of cases, with a percentage of neutrophils >50% in 55% of cases. Protein level was increased in 43% of cases. In blood, C-reactive protein was elevated in 67% of cases. Other blood parameters were unremarkable. Clinical and laboratory features did not differ from those related to other pathogens that caused meningitis and meningoencephalitis. Hence, unnecessary treatment for other infections is frequently instituted during EV infections. Virologic diagnosis is important to distinguish between EV and other treatable bacterial and viral diseases.

PCR-based diagnostics for infectious diseases: uses, limitations, and future applications in acute-care settings

Molecular diagnostics are revolutionising the clinical practice of infectious disease. Their effects will be significant in acute-care settings where timely and accurate diagnostic tools are critical for patient treatment decisions and outcomes. PCR is the most well-developed molecular technique up to now, and has a wide range of already fulfilled, and potential, clinical applications, including specific or broad-spectrum pathogen detection, evaluation of emerging novel infections, surveillance, early detection of biothreat agents, and antimicrobial resistance profiling. PCR-based methods may also be cost effective relative to traditional testing procedures. Further advancement of technology is needed to improve automation, optimise detection sensitivity and specificity, and expand the capacity to detect multiple targets simultaneously (multiplexing). This review provides an up-to-date look at the general principles, diagnostic value, and limitations of the most current PCR-based platforms as they evolve from bench to bedside.

Clinical relevance of polymerase chain reaction (PCR) assays and antigen-driven immunoblots for the diagnosis of neurological infectious diseases

Polymerase chain reaction assays are a powerful tool for detecting the presence of infectious genomes in the cerebrospinal fluid. Positive results always mean a current or pending infection of the central nervous system. Subacute (>7 days) or chronic infections induce an intrathecal humoral immune response and the appearance of oligoclonal IgG antibodies directed against the causal infectious agent. This local synthesis may be observed even in cases of severe systemic immunodeficiency. The use of polymerase chain reactions in combination with the detection of a specific intrathecal immune response should represent the most reliable strategy for the diagnosis of viral and chronic infections of the central nervous system. The authors describe their experience, using this approach, in herpetic encephalitis, acute and recurrent herpetic meningitis, varicella zoster-induced neurological diseases, cytomegalovirus encephalitis, progressive multifocal leukoencephalitis and tuberculous meningitis.

Hand, foot and mouth disease in an immunocompromised adult treated with aciclovir

A 27-year-old man, immunosuppressed from recent chemotherapy for metastatic Ewing's sarcoma, presented with a 1-week history of a painful, pruritic, papulovesicular eruption on the hands and feet. A diagnosis of hand, foot and mouth disease was made based on histology, detection of Enterovirus ribonucleic acid by polymerase chain reaction on a swab from a vesicle, and a four-fold increase in Enterovirus antibody levels. At no stage however, were there lesions in the mouth. Another unusual feature in this case was a prolonged course, presumably as a result of immunosuppression. After 3 1/2 weeks he was commenced on oral aciclovir 200 mg five times daily, with subsequent resolution of all lesions within 5 days. There may be a role for systemic aciclovir in some patients with hand, foot and mouth disease.

A retrospective clinical, laboratory and outcome analysis in 43 cases of acute aseptic meningitis

Forty-three consecutive cases of acute aseptic meningitis (AAM) presenting within a 24-months period were retrospectively analysed with respect to clinical symptomatology, cerebrospinal fluid (CSF) findings, clinical course, treatment and outcome. Nineteen of the 43 AAM cases (44%) were caused by enterovirus, one by HIV (2%), two by Varicella zoster virus (5%), three due to herpes simplex virus I (7%), two due to herpes simplex virus II (5%), one due to Central European encephalitis virus (2%), and in 15 patients (35%) the aetiology of AAM remained unknown. Headache (100%) and fever (93%) were the presenting symptoms in the majority of cases. Signs of preceding infection were predominantly gastrointestinal in the enterovirus subgroup, but were inconsistently observed in the other subgroups. CSF findings at the first lumbar tap on admission generally revealed lymphomonocytic pleocytosis of less than 500 cells per micro l, mild to moderately elevated protein and normal lactate and glucose levels. Initial therapy consisted of an empirical antiviral and antibiotic regimen until a serological diagnosis was available. Acyclovir, effective only in herpes family viruses, was initially administered to all AAM cases. Effective therapy for other viral pathogens are not broadly available and treating AAM of unknown aetiology imposes a particular problem. The average hospitalization time ranged from 16 to 31 days. Patients were either discharged home (72%) or transferred to a rehabilitation centre (28%). The outcome was good (40%) to fair (51%) in the majority of cases.

Determination of enterovirus serotype inferred from sequence analysis of PCR products

BACKGROUND

Enterovirus infections are common in neonates. Virus isolation is the only diagnostic method to confirm enterovirus serotype infections, however, is not always successful.

OBJECTIVES

A new approach for the diagnosis of enterovirus infections was performed, using the reference strain inferred from sequence analysis of PCR products.

STUDY DESIGN

Virus isolation, enterovirus RT-PCR and sequence analysis were performed from clinical samples or stored sera from two neonates with fever and rash. Neutralizing test (NT) antibodies against prototype reference virus were measured in paired sera.

RESULTS

Virus isolation was negative in both patients but the enterovirus genome was amplified in the acute phase sera obtained from the two patients. From the results of sequence analysis of 109 nucleotides located in the 5'-noncoding of the conserved region of enteroviruses, a high homology to echovirus types 25 and 30 was found. More than a 4-fold increase in NT antibodies against reference viruses was demonstrated in the acute and convalescent phase sera. They were confirmed as echovirus type 25 and 30 infection, respectively.

CONCLUSIONS

These virological examinations are practical and useful for clinical settings for a diagnosis of enterovirus infections because of an insufficient positive rate in virus isolation.

Sudden death in a 35-year-old man with occult malformation of the brain and aseptic meningitis

A 35-year-old man was found dead by his wife. He was reported to have had symptoms of a common cold the week preceding his death. The medicolegal autopsy yielded signs of central dysregulation (ectasia of the urinary bladder and rectum, dystelectasis of the lungs) together with marked brain edema and fresh bite marks on the tongue. The cause of death was presumed to be lethal epileptic seizure. Neuropathologic examination revealed neuronal nodular heterotopia as well as discrete lymphocytic meningitis (aseptic meningitis). The death was most probably caused by the combination of the meningitis with the occult malformation, leading to a lowered seizure threshold and subsequent lethal seizure. The morphologic findings of this case are presented, and the probable mechanisms of death are discussed.

Molecular analysis of cerebrospinal fluid in viral diseases of the central nervous system

The use of nucleic acid (NA) amplification techniques has transformed the diagnosis of viral infections of the central nervous system (CNS). Because of their enhanced sensitivity, these methods enable detection of even low amounts of viral genomes in cerebrospinal fluid. Following more than 10 years of experience, the polymerase chain reaction or other NA-based amplification techniques are nowadays performed in most diagnostic laboratories and have become the test of choice for the diagnosis of several viral CNS infections, such as herpes encephalitis, enterovirus meningitis and other viral infections occurring in human immunodeficiency virus-infected persons. Furthermore, they have been useful to establish a viral etiology in neurological syndromes of dubious origin and to recognise unusual or poorly characterised CNS diseases. Quantitative methods have provided a valuable additional tool for clinical management of these diseases, whereas post-amplification techniques have enabled precise genome characterisation. Current efforts are aiming at further improvement of the diagnostic efficiency of molecular techniques, their speed and standardisation, and to reduce the costs. The most relevant NA amplification strategies and clinical applications of to date will be the object of this review.

A season of aseptic meningitis in Germany: epidemiologic, clinical and diagnostic aspects

OBJECTIVE

We assessed epidemiologic, clinical and laboratory features of aseptic meningitis during one season of multiserotype enteroviral meningitis in East Germany in 70 consecutive patients with aseptic meningitis admitted to the Children's University Hospital Leipzig.

RESULTS

Patients, age 1 to 16 years, typically presented with headache, emesis and fever, whereas signs of meningeal irritation were only moderately expressed in one-half of the patients. The median number of leukocytes in the CSF was 151 cells/mm(3) (range, 2 to 1,820) with a high percentage of polymorphonuclear cells (PMNs). Initial blood counts showed mild leukocytosis and pronounced PMN predominance (78.9 +/- 1.3%). The percentage of PMNs in the peripheral blood decreased in favor of mononuclear cells after 3 days to a pattern more compatible with viral infection as opposed to that suggestive for bacteria in the beginning. Mean cerebrospinal fluid values of protein, glucose and lactate and the C-reactive protein were mildly elevated or normal. Nonpolio enteroviruses were detected in 30 of 70 patients. Subsequent serotyping revealed echovirus type 13 (13 patients), type 6 (2), type 30 (1) and coxsackie B virus type 5 (2). There were no differences in demographic or clinical data between enterovirus positive and negative patients.

CONCLUSIONS

Even though individual laboratory values do not solely allow discrimination between viral and bacterial meningitis, the combined epidemiologic, clinical and laboratory data facilitate the diagnosis of aseptic meningitis in most cases. Viral diagnostics, identifying echovirus type 13 that thus far has not been associated with epidemics of meningitis, adds important epidemiologic information.

Clinical manifestations and laboratory assessment in an enterovirus 71 outbreak in southern Taiwan

An epidemic of enterovirus 71 (EV71) infection compatible with hand, foot and mouth disease and associated with high morbidity and mortality occurred in Taiwan in 1998. We recruited 90 patients (50 males, 40 females) with definite EV71 infections for clinical and laboratory analysis. The neurological signs and symptoms, all of which occurred during the febrile period, in patients with central nervous system (CNS) involvement (aseptic meningitis, encephalitis or myelitis) were myoclonic jerks (23/33), vomiting (10/33), ataxia (7/33), lethargy (6/33), seizure (4/33) and tremor (2/33). Patients with CNS involvement had longer durations of fever (4.6+/-0.2 vs. 3.1+/-0.3 d; p <0.01) and a higher white blood cell count (12,512+/-658 vs. 10,607+/-409 cells/mm3; p = 0.01) than patients without CNS involvement. The case fatality rate in patients with CNS involvement was 4/33 (12%), whereas no fatalities (0/57) occurred in patients without CNS involvement. Six of 11 patients subjected to MRI showed a high intensity T2-weighted signal in the brainstem. A nested fluorescent RT-PCR for detection of virus in throat and stool specimens showed higher sensitivity than viral culture. Viremia was detectable using RT-PCR in 20% of cases (3/15), whereas no virus was isolated from culture or detected by RT-PCR in cerebrospinal fluid.

Clinical and epidemiological aspects of an enterovirus outbreak in a neonatal unit

An outbreak of enterovirus infection occurred among neonates in a maternity hospital between July 7 and 22, 1999. Twenty neonates became ill (18 confirmed and two probable), an attack rate of 33%. The incubation period ranged from three to six days (mean, 4.2). The male:female ratio was 11:9 and the mean age at the onset of illness was 5.5 days. All the babies had fever, eight, a maculopapular rash, and six had symptoms of gastroenteritis, 11 developed meningitis. Nineteen neonates required hospitalization for three to seven days, but all were discharged home without sequelae. Enteroviral RNA was detected in all of 18 urines, and 14 cerebrospinal fluid specimens tested. A case-control study was conducted to determine risk factors associated with the outbreak. Rooming in the nursery ward was a significant risk factor (odds ratio=33.35; 95% confidence interval, 3.79-800; P=0.00002). No association was found between illness and other possible risk factors. Appropriate control measures resulted in resolution of the outbreak. Our findings demonstrate the potential for enteroviruses to cause widespread illness among newborns, and emphasize the usefulness of polymerase chain reaction in the early diagnosis of infection, and underline the role of effective control measures in interrupting viral transmission.

Application of polymerase chain reaction and subsequent phylogenetic analysis to the diagnosis of enteroviral infection in the central nervous system

BACKGROUND

Enteroviral infections of the central nervous system (CNS) are often difficult to diagnose, even if consistent conventional laboratory methodologies are used.

OBJECTIVES

To clarify the efficiency of two polymerase chain reaction (PCR) methods for the sensitive detection of enteroviruses and for the identification of enteroviral genotypes based on phylogenetic analysis of the amplified genome sequences, and to facilitate the diagnosis of enteroviral infection in CNS.

STUDY DESIGN

Cerebrospinal fluid (CSF), throat swab, rectal swab, and/or serum samples were collected from 171 patients with aseptic meningitis and 67 patients with febrile seizures. The samples were tested for the presence of enteroviruses by cell culture and PCR methods for the detection and identification of enteroviruses.

RESULTS

In 111 (64.9%) of 171 patients with aseptic meningitis, enteroviruses were isolated by cell cultures from any site. In 143 (83.6%) patients, including 110 of 111 patients with aseptic meningitis, the enteroviral genome was detected in CSF by PCR. No enterovirus was isolated from any site for the 67 patients with febrile seizures. PCR detected the enteroviral genome in CSF samples from 13 (61.9%) of 21 patients who developed febrile seizures in the summer (June-August). Phylogenetic analysis of amplified genome sequences showed that the major pathogens of febrile seizures in summer were group A coxsackieviruses, which are usually difficult to isolate by cell culture.

CONCLUSION

PCR methods for the detection and identification of enteroviruses were useful for the diagnosis of enteroviral infection in CNS.

Impact of rapid polymerase chain reaction results on management of pediatric patients with enteroviral meningitis

BACKGROUND

Enterovirus (EV) infections can be rapidly detected by PCR. However, several studies suggest that results must be available early in the management of the patient to impact significantly on patient care. We evaluated this hypothesis directly during an outbreak of EV aseptic meningitis.

METHODS

From June through November, 1998, EV PCR was performed 5 days a week on cerebrospinal fluid specimens from pediatric patients evaluated for meningitis. We compared antibiotic use, length of stay and hospital charges in a group of patients with EV meningitis whose positive EV PCR results were available within 24 h of specimen collection, to a group of similar patients whose results were available >24 h after collection.

RESULTS

Cerebrospinal fluid specimens were submitted for EV PCR from 113 patients with suspected EV meningitis, and 50 of 113 (44%) were positive. Of these 50 EV-PCR-positive patients, 17 of 50 (34%) had EV PCR results available in < or = 24 h and 33 of 50 (66%) had results available in >24 h. Patients with EV-positive results reported < or = 24 h after specimen collection had 20 h less of antibiotic use (P = 0.006) and $2,798 less in hospital charges (P = 0.001) than patients with positive results available in >24 h. Hospitalized patients who received positive results rapidly did not have significantly less antibiotic therapy or shorter length of stay, but hospital charges were reduced by $2,331 (P = 0.009).

CONCLUSION

Rapid reporting of PCR results can have a significant impact on several outcome measures for patients with EV meningitis.

The pathogenesis of febrile seizures: is there a role for specific infections?

Although fever is regarded as the main trigger in the pathogenesis of febrile seizures (FS), it is not supposed to be the unique causative factor. In FS, there is a strong familial predisposition. This does not exclude infections as a causative factor because subtle genetic polymorphisms have been demonstrated to affect the course of infections. We review the literature on: (1) the role of fever, especially the height of temperature, its cause, and metabolic effects induced by temperature; (2) the role of heredity; (3) the role of cytokines which play a role in the induction of fever; and (4) the role of type of infection, with emphasis on newly identified agents and improved diagnostic techniques. With modern molecular techniques such as PCR, viruses have been detected in the CSF far more often than previously thought, even in the absence of pleocytosis of the CSF. This makes it difficult to distinguish FS from acute encephalitis. FS may be caused by neuroinvasion or intracerebral activation of viruses. Further studies should focus on these options because therapeutic intervention is possible and may prevent late sequelae such as recurrent FS and subsequent epilepsy.

Evaluation of a one-tube RT-PCR system for detection of enteroviruses

BACKGROUND

A highly sensitive PCR assay for early and rapid detection of enteroviral (EV) RNA in CSF is necessary to investigate the role of EV in acute neurological illnesses.

OBJECTIVES

To evaluate and compare two PCR protocols (Titan one-tube RT-PCR and random primed RT-PCR) for detection of enteroviral RNA in CSF.

STUDY DESIGN

The PCR protocols were evaluated for lower limit of input detection using log dilutions of five stock EV strains and an isolate of enterovirus-71 in minimum essential medium and three EV stock strains in CSF. The tests were also applied on 77 CSF samples, 46 from patients with suspected acute EV neurological illness and 31 from 'disease controls'.

RESULTS

Even though in the initial virus titration assays there was no statistically significant difference in the limit of input detection by Titan system and the random primed two-step PCR, the latter had a higher positivity rate when used on CSF samples from patients (20/46 vs. 10/46, P<0.01).

CONCLUSIONS

Random primed RT-PCR assay is superior to Titan one-tube RT-PCR for detection of EV RNA in CSF.

Detection of enteroviruses in cases of neurological disorders in the State of Pará, Brazil

Eighty-one cerebrospinal fluid (CSF) samples mainly from cases of aseptic meningitis and motor deficiency syndrome were sent to the Virology Section of Evandro Chagas Institute, Belém Pará, in the period of January 1995 to January 1996 in order to isolate viruses. All samples were inoculated onto HEp-2 cell culture and newborn mice, with negative results. The probability of isolating viruses by these methods is reduced because of the low concentration of viral particles in these specimens. In order to obtain more information about the etiology of these cases, a group of 23 samples were selected to be tested by a more sensitive technique than the virus isolation - the reverse transcription polymerase chain reaction (RT-PCR). Specific primers directed to conserved regions in the enterovirus genome were used, considering that this group of viruses is frequently associated with these neurological disorder. The age of the patients ranged from 1 to 55 years and nearly all of them lived in Belém, State of Pará, North of Brazil. Of 15 samples analyzed by RT PCR nine (60%) were positive; of these, 6 (66.6%) had motor deficiency and 3 (33.3%) developed aseptic meningitis. These results show that it is important to investigate enterovirus as cause of these syndromes.

The intrathecal humoral immune response: laboratory analysis and clinical relevance

In normal conditions, albumin and immunoglobulin (Ig)G in the cerebrospinal fluid (CSF) originate from the blood, and there is no antibody production within the central nervous system. Up to 20% of CSF proteins are intrathecally synthesized, but the major fraction is blood-derived. The CSF/serum albumin quotient (QAlb) is the best marker of the blood-CSF barrier function. The corresponding immunoglobulin quotients (QIGG, QIGA, QIGM) are not linearly related to QAlb and their correlations are defined by an hyperbolic equation. This equation is used to discriminate between a blood-derived and a locally produced fraction of immunoglobulins in case of an intrathecal humoral immune response. The detection of CSF-specific oligoclonal IgG is more sensitive than the quantitative comparison between QIGG and QAlb. A further step is the determination of antibody indices and the detection of specific oligoclonal antibodies by antigen-driven immunoblots. CSF analysis remains a cornerstone for the diagnosis of various neurological disorders, including multiple sclerosis and infectious diseases of the central nervous system.

Successful treatment of enterovirus infection with the use of pleconaril in 2 infants with severe combined immunodeficiency

Two patients with severe combined immunodeficiency and enterovirus infections were successfully treated with pleconaril. There were no adverse affects.

Detection of enteroviruses in the cerebrospinal fluid by polymerase chain reaction: prospective study of impact on the management of hospitalized children

A polymerase chain reaction kit (AMPLICOR EV) for the detection of enteroviruses (EV-PCR) in the cerebrospinal fluid (CSF) was evaluated in clinical conditions in a prospective blinded-intention study. Forty-three children (mean age 2.7 years) hospitalized for suspected meningitis or fever of unclear etiology were enrolled. EV-PCR was performed on a daily basis. Results were available in less than 2 days in 72% of cases. EV-PCR was positive in nine (21%) children, including three infants without CSF pleocytosis. Knowing their EV-PCR result would have allowed a saving of 18 hospital days and 12 days of antibiotic therapy. The EV-PCR in the CSF can thus be practically useful for children hospitalized for meningitis or fever if available on-site on a daily basis.

Outbreak of echovirus 30 meningitis in Switzerland

This study includes 80 patients (38 children and 42 adults) who contracted aseptic meningitis in the summer of 1996 in Fribourg, Switzerland. Virological studies revealed an enteroviral infection in 65 out of 70 (93%) investigated patients. In 47 out of the 53 cases (89%) where a precise virus could be identified, the causative agent was an Echovirus 30. More than 50 patients lived in an area within a 5-km radius. The patients presented with the classic symptoms and signs of aseptic meningitis. In contrast, polymorphonuclear leukocytes predominated in the cerebrospinal fluid in the first 24 h and 32% of the cases had a left shift in their peripheral blood smear. The patients' age did not influence white blood cell count, the proportion of polymorphonuclear leukocytes or protein concentration in the cerebrospinal fluid. Thirty-three patients (41%) received antibiotic treatment, and 38 patients (48%) left the hospital within 24 h. Only 2 neuroradiological procedures and 1 electroencephalographic recording were performed. The outcome was favourable in all patients.