Detection of both herpes simplex and varicella-zoster viruses in cerebrospinal fluid from patients with encephalitis

Disseminated herpes simplex virus and varicella zoster virus co-infection in a patient with idiopathic thrombocytopenic purpura

Concomitant disseminated herpes simplex virus (HSV) and varicella zoster virus (VZV) infection is a rare event. We describe a case of disseminated HSV and VZV infection in an 80-year-old patient many years after splenectomy for idiopathic thrombocytopenic purpura (ITP). This is the first case of disseminated HSV-1 and VZV infection with molecular evidence of the simultaneous presence of both viruses in two different body sites (the skin and cerebrospinal fluid). This adds to the three reports of patients developing cutaneous disseminated herpes zoster multiple years after splenectomy for ITP.

Viral infections of the central nervous system in Spain: a prospective study

The aim of the study was to determine the incidence of viruses causing aseptic meningitis, meningoencephalitis, and encephalitis in Spain. This was a prospective study, in collaboration with 17 Spanish hospitals, including 581 cases (CSF from all and sera from 280): meningitis (340), meningoencephalitis (91), encephalitis (76), febrile syndrome (7), other neurological disorders (32), and 35 cases without clinical information. CSF were assayed by PCR for enterovirus (EV), herpesvirus (herpes simplex [HSV], varicella-zoster [VZV], cytomegalovirus [CMV], Epstein-Barr [EBV], and human herpes virus-6 [HHV-6]), mumps (MV), Toscana virus (TOSV), adenovirus (HAdV), lymphocytic choriomeningitis virus (LCMV), West Nile virus (WNV), and rabies. Serology was undertaken when methodology was available. Amongst meningitis cases, 57.1% were characterized; EV was the most frequent (76.8%), followed by VZV (10.3%) and HSV (3.1%; HSV-1: 1.6%; HSV-2: 1.0%, HSV non-typed: 0.5%). Cases due to CMV, EBV, HHV-6, MV, TOSV, HAdV, and LCMV were also detected. For meningoencephalitis, 40.7% of cases were diagnosed, HSV-1 (43.2%) and VZV (27.0%) being the most frequent agents, while cases associated with HSV-2, EV, CMV, MV, and LCMV were also detected. For encephalitis, 27.6% of cases were caused by HSV-1 (71.4%), VZV (19.1%), or EV (9.5%). Other positive neurological syndromes included cerebellitis (EV and HAdV), seizures (HSV), demyelinating disease (HSV-1 and HHV-6), myelopathy (VZV), and polyradiculoneuritis (HSV). No rabies or WNV cases were identified. EVs are the most frequent cause of meningitis, as is HSV for meningoencephalitis and encephalitis. A significant number of cases (42.9% meningitis, 59.3% meningoencephalitis, 72.4% encephalitis) still have no etiological diagnosis.

Aetiologies of central nervous system infection in Viet Nam: a prospective provincial hospital-based descriptive surveillance study

Background

Infectious diseases of the central nervous system (CNS) remain common and life-threatening, especially in developing countries. Knowledge of the aetiological agents responsible for these infections is essential to guide empiric therapy and develop a rational public health policy. To date most data has come from patients admitted to tertiary referral hospitals in Asia and there is limited aetiological data at the provincial hospital level where most patients are seen.

Methods

We conducted a prospective Provincial Hospital-based descriptive surveillance study in adults and children at thirteen hospitals in central and southern Viet Nam between August 2007– April 2010. The pathogens of CNS infection were confirmed in CSF and blood samples by using classical microbiology, molecular diagnostics and serology.

Results

We recruited 1241 patients with clinically suspected infection of the CNS. An aetiological agent was identified in 640/1241 (52%) of the patients. The most common pathogens were Streptococcus suis serotype 2 in patients older than 14 years of age (147/617, 24%) and Japanese encephalitis virus in patients less than 14 years old (142/624, 23%). Mycobacterium tuberculosis was confirmed in 34/617 (6%) adult patients and 11/624 (2%) paediatric patients. The acute case fatality rate (CFR) during hospital admission was 73/617 (12%) in adults and to 42/624 (7%) in children.

Conclusions

Zoonotic bacterial and viral pathogens are the most common causes of CNS infection in adults and children in Viet Nam.

Varicella-zoster virus (VZV) glycoprotein E is a serological antigen for detection of intrathecal antibodies to VZV in central nervous system infections, without cross-reaction to herpes simplex virus 1

Herpes simplex virus 1 (HSV-1) and varicella-zoster virus (VZV) cause serious central nervous system (CNS) diseases that are diagnosed with PCR using samples of cerebrospinal fluid (CSF) and, during later stages of such infections, with assays of intrathecal IgG antibody production. However, serological diagnoses have been hampered by cross-reactions between HSV-1 and VZV IgG antibodies and are commonly reported in patients with herpes simplex encephalitis (HSE). In this study we have evaluated VZV glycoprotein E (gE) as a new antigen for serological diagnosis of VZV-induced CNS infections. Paired samples of CSF and serum from 29 patients with clinical diagnosis of VZV CNS infection (n = 15) or HSE (n = 14), all confirmed by PCR, were analyzed. VZV gE and whole VZV were compared as antigens in enzyme-linked immunosorbent assays (ELISAs) for serological assays in which the CSF/serum sample pairs were diluted to identical IgG concentrations. With the gE antigen, none of the HSE patients showed intrathecal IgG antibodies against VZV, compared to those shown by 11/14 patients using whole-VZV antigen (P < 0.001). In the patients with VZV infections, significantly higher CSF/serum optical density (OD) ratios were found in the VZV patients using the VZV gE antigen compared to those found using the whole-VZV antigen (P = 0.001). These results show that gE is a sensitive antigen for serological diagnosis of VZV infections in the CNS and that this antigen was devoid of cross-reactivity to HSV-1 IgG in patients with HSE. We therefore propose that VZV gE can be used for serological discrimination of CNS infections caused by VZV and HSV-1.

DNA probe array for the simultaneous identification of herpesviruses, enteroviruses, and flaviviruses

Viral infections of the central nervous system (CNS) are caused by a variety of viruses, namely, herpesviruses, enteroviruses, and flaviviruses. The similar clinical signs provoked by these viruses make the diagnosis difficult. We report on the simultaneous detection of these major CNS pathogens using amplification by PCR and detection of amplified products using DNA microarray technology. Consensus primers were used for the amplification of all members of each genus. Sequences specific for the identification of each virus species were selected from the sequence alignments of each target gene and were synthesized on a high-density microarray. The amplified products were pooled, labeled, and cleaved, followed by hybridization on a single array. This method was successfully used to identify herpesviruses, namely, herpes simplex virus type 1 (HSV-1), HSV-2, and cytomegalovirus; all serotypes of human enteroviruses; and five flaviviruses (West Nile virus, dengue viruses, and Langat virus). This approach, which used highly conserved consensus primers for amplification and specific sequences for identification, would be extremely useful for the detection of variants and would probably help solve some unexplained cases of encephalitis. The analytical sensitivity of the method was shown to be 500 genome equivalents ml(-1) for HSV-1, 0.3 50% tissue culture infectious doses (TCID50s) ml(-1) for the enterovirus coxsackievirus A9, and 200 TCID50s ml(-1) for West Nile virus. The clinical sensitivity of this method must now be evaluated.

Detection and species identification of four human herpesviruses using polymerase chain reaction coupled with restriction endonuclease analysis

A polymerase chain reaction (PCR) based assay for detection and species identification of four human herpesviruses, including herpes simplex virus types 1 and 2, Epstein-Barr virus, and cytomegalovirus was developed. The detection of the herpesviruses was achieved by seminested PCR with three primers targeting well-conserved regions within the DNA-polymerase gene. Virus species were identified by simple restriction enzyme digestion of the amplified products with TaqI or RsaI. In comparison with mono-specific nested PCR assays the tetra-specific assay demonstrated similar specificity and sensitivity with reference and clinical samples. The tetra-specific assay is sensitive, cost effective, and can be used for examination of clinical samples of different origin.

Laboratory diagnosis of common herpesvirus infections of the central nervous system by a multiplex PCR assay

A sensitive multiplex PCR assay for single-tube amplification that detects simultaneous herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2), varicella-zoster virus (VZV), human cytomegalovirus (CMV), and Epstein-Barr virus (EBV) is reported with particular emphasis on how the method was optimized and carried out and its sensitivity was compared to previously described assays. The assay has been used on a limited number of clinical samples and must be thoroughly evaluated in the clinical context. A total of 86 cerebrospinal fluid (CSF) specimens from patients which had the clinical symptoms of encephalitis, meningitis or meningoencephalitis were included in this study. The sensitivity of the multiplex PCR was determined to be 0.01 and 0.03 50% tissue culture infective doses/the reciprocal of the highest dilution positive by PCR for HSV-1 and HSV-2 respectively, whereas for VZV, CMV and EBV, 14, 18, and 160 ag of genomic DNA were detected corresponding to 48, 66, and 840 genome copies respectively. Overall, 9 (10.3%) of the CSF samples tested were positive in the multiplex PCR. HSV-1 was detected in three patients (3.5%) with encephalitis, VZV was detected in four patients (4.6%) with meningitis, HSV-2 was detected in one neonate (1.16%), and CMV was also detected in one neonate (1.16%). None of the samples tested was positive for the EBV genome. None of the nine positive CSF samples presented herpesvirus coinfection in the central nervous system. Failure of DNA extraction or failure to remove any inhibitors of DNA amplification from CSF samples was avoided by the inclusion in the present multiplex PCR assay of alpha-tubulin primers. The present multiplex PCR assay detects simultaneously five different herpesviruses and sample suitability for PCR in a single amplification round of 40 cycles with an excellent sensitivity and can, therefore, provide an early, rapid, reliable noninvasive diagnostic tool allowing the application of antiviral therapy on the basis of a specific viral diagnosis. The results of this preliminary study should prompt a more exhaustive analysis of the clinical value of the present multiplex PCR assay.

Simultaneous detection of 6 human herpesviruses in cerebrospinal fluid and aqueous fluid by a single PCR using stair primers

A Herpes Consensus allows the simultaneous detection of 6 human herpesviruses: herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2), human cytomegalovirus (HCMV), varicella-zoster virus (VZV), Epstein-Barr virus (EBV), and human herpes virus 6 (HHV-6). This technique was used first to examine retrospectively 100 DNA extracts from 95 CSF and 5 aqueous fluids, prepared by treatment by saturated NaCl followed by ethanol precipitation (n = 63) or by simple boiling (n = 37) and stored at -80 degrees C, and secondly to test prospectively 38 CSF samples for which two DNA extracts were prepared with commercially available DNA extraction kits. In all cases, the results were compared with those of an "in-house" PCR. Concordant results between both PCR and the Herpes Consensus techniques were obtained in 61 of 63 DNA extracts prepared by treatment by saturated NaCl (97%) and in only 31 of 37 boiled samples (84%). Both commercially available methods of DNA extraction examined appear to be suitable for Herpes Consensus PCR, although they cannot remove completely PCR inhibitors that must be sought in case of negative results. This preliminary study shows that the Herpes Consensus method should be of value for rapid diagnosis of herpesvirus infections on condition that it is performed on purified DNA extracts.

Development of a PCR procedure for the detection of a herpes-like virus infecting oysters in France

A PCR-based procedure for detecting a herpes-like virus that infects the Japanese oyster, Crassostrea gigas, in France was developed. Two primers were designed to provide specific amplification products ranging in size from 917 to 1001 bp when carried out on oyster herpes-like virus DNA. No amplification was observed of oyster genomic DNA nor of the DNA from vertebrate herpesviruses. Crude samples were prepared and submitted to nested PCR, allowing amplification of DNA fragments of the expected size when carried out on infected larval and spat samples. The procedure used to prepare the sample for PCR was found to be critical because of the presence of unidentified substances in oyster tissues that inhibit the PCR reaction. A rapid and convenient sample preparation using ground tissues allowed a sensitive detection of the herpes-like virus infected oysters. The ability of the defined PCR protocol to diagnose herpes-like virus infections in oysters was compared to the transmission electron microscopy technique using 15 C. gigas larval batches with or without mortalities. PCR amplification is as sensitive a diagnostic assay for herpes-like virus as transmission electron microscopy. However, the nested PCR protocol is more convenient and less time consuming. The relationship between reported mortalities among C. gigas oyster spat and herpes-like virus DNA detection by PCR was also investigated. Statistical analysis showed that virus detection and mortalities are correlated. This observation highlights the importance of studying the causative role of herpes-like virus in oyster spat mortalities.

Nested PCR for rapid detection of mumps virus in cerebrospinal fluid from patients with neurological diseases

In this study, we have developed a reverse transcription (RT)-nested polymerase chain reaction (n-PCR) for the detection of mumps virus RNA in cerebrospinal fluid (CSF) from patients with neurological infections. A specific 112-bp fragment was amplified by this method with primers from the nucleoprotein of the mumps virus genome. The mumps virus RT-n-PCR was capable of detecting 0.001 PFU/ml and 0.005 50% tissue culture infective dose/ml. This method was found to be specific, since no PCR product was detected in each of the CSF samples from patients with proven non-mumps virus-related meningitis or encephalitis. Mumps virus RNA was detected in all 18 CSF samples confirmed by culture to be infected with mumps virus. Positive PCR results were obtained for the CSF of 26 of 28 patients that were positive for signs of mumps virus infection (i.e., cultivable virus from urine or oropharyngeal samples or positivity for anti-mumps virus immunoglobulin M) but without cultivable virus in their CSF. Overall, mumps virus RNA was detected in CSF of 96% of the patients with a clinical diagnosis of viral central nervous system (CNS) disease and confirmed mumps virus infection, while mumps virus was isolated in CSF of only 39% of the patients. Furthermore, in a retrospective study, we were able to detect mumps virus RNA in 25 of 55 (46%) CSF samples from patients with a clinical diagnosis of viral CNS disease and negative laboratory evidence of viral infection including mumps virus infection. The 25 patients represent 12% of the 236 patients who had a clinical diagnosis of viral CNS infections and whose CSF was examined at our laboratory for a 2-year period. The findings confirm the importance of mumps virus as a causative agent of CNS infections in countries with low vaccine coverage rates. In summary, our study demonstrates the usefulness of the mumps virus RT-n-PCR for the diagnosis of mumps virus CNS disease and suggests that this assay may soon become the "gold standard" test for the diagnosis of mumps virus CNS infection.

Viral diagnosis of neurological infection by RT multiplex PCR: a search for entero- and herpesviruses in a prospective study

The diagnosis of a wide range of different neurological syndromes was established by a reverse transcription multiplex PCR assay. The presence of enterovirus and herpesviruses was studied in cerebrospinal fluid samples collected prospectively from 200 patients hospitalized with neurological diseases suspected of viral infection. Positive PCR results for enterovirus and neurotropic herpesvirus (herpes simplex, HSV, and varicella zoster, VZV) were obtained among the immunocompetent patients (55/156, 35%) who presented aseptic meningitis or encephalitis. Among immunocompromised patients the yield of positive PCR results was 41% (18/44), predominantly lymphotropic herpesviruses (15/44, 34%). Cytomegalovirus (CMV) DNA was detected in patients with several clinical syndromes, including encephalitis, chronic meningitis, retinitis, ventriculitis, polyradiculomyelitis, and myeloradiculitis. Epstein-Barr (EBV) and VZV-specific DNA sequences were detected in patients with either encephalitis, aseptic meningitis, and chronic meningitis. Dual infections of CMV and HSV or CMV and EBV were established in two AIDS patients with encephalitis and polyradiculomyelitis, respectively. The applications of this RT multiplex PCR assay are extensive and may prove to be particularly valuable for the rapid and sensitive diagnosis of neurological diseases in both immunocompetent and immunocompromised patients.

The detection of intrathecal synthesis of anti-herpes simplex IgG antibodies: comparison between an antigen-mediated immunoblotting technique and antibody index calculations. European Union Concerted Action on Virus Meningitis and Encephalitis

The detection of intrathecal antibody synthesis was compared by the calculation of antibody indices (AI) derived from ELISA techniques with the detection of virus-specific oligoclonal IgGs by an antigen-mediated capillary blot technique. Twenty-seven paired serum and cerebrospinal fluid (CSF) samples were examined from 15 immunocompetent patients with herpes simplex virus encephalitis (HSE) diagnosed by PCR on early CSF samples. These techniques were also applied to paired samples from 20 multiple sclerosis (MS) patients, 10 patients with other inflammatory neurological diseases and 10 patients with non inflammatory neurological disorders. There was a good correlation between the results obtained by AI and those obtained by immunoblotting, especially in HSE (2 discordant results out of 27). Discrepancies were more frequent (25%) in MS patients where a "polyspecific" reaction characterized by low affinity antibodies is known to occur. Some of the discrepancies could, in part, be due to serological cross-reaction with varicella zoster virus.

Specific diagnostic methods for herpesvirus infections of the central nervous system: a consensus review by the European Union Concerted Action on Virus Meningitis and Encephalitis

BACKGROUND

Herpesvirus infections of the central nervous system are often severe but are fortunately rare. The incidence of these infections has however, increased in recent years as a consequence of an increase in the number of immune-compromised individuals. New diagnostic procedures have improved our ability to diagnose these infections and herpesviruses may yet be implicated as the cause of further neurological diseases with no known aetiology. Methodological standards for selection and evaluation of patient materials are essential to the provision of reliable diagnosis, yet few studies have addressed this important issue.

OBJECTIVES

To describe and define methodological standards and reference methodology for diagnosis of herpesvirus infections of the CNS.

STUDY DESIGN

Information gathered by literature review.

RESULTS

Only for herpes simplex encephalitis is there sufficient data to allow the definition of reference methodology. Good methodological standards exist but few studies have adhered to these standards. As methods for the detection of specific intrathecal antibody synthesis are well established yet under-used in diagnostic virology, the principle of these measurements is reviewed in some detail.

CONCLUSIONS

Herpesvirus infections of the CNS are of increasing importance. High quality, multi-centre studies are needed to establish the value of the new diagnostic test procedures if further improvement in the diagnostic sensitivity and specificity of these procedures is to be achieved.

Detection of enteroviral RNA and specific DNA of herpesviruses by multiplex genome amplification

A reverse transcription (RT) multiplex polymerase chain reaction (PCR) assay was developed to allow rapid, sensitive and simultaneous detection of enteroviral RNA and herpesviral DNA specific sequences in a single tube. The method involves a reverse transcription step followed by a multiplex nested PCR in which the combination of primers amplifies cDNA from enteroviruses and specific herpesviruses DNA. Nested amplification utilises primers designed to anneal into the amplification product from the first reaction. Individual viruses were then detected and differentiated by the size of their PCR products determined using ethidium bromide stained agarose gels. To exclude false negatives due to sample inhibitors an internal amplification control, a cloned fragment of DNA from Pseudorabies virus (PRV DNA) was included in the reaction mixture. Detection levels between 0.01 and 0.001 TCID50 of prototype strains of Polio and Coxsackie type B viruses and between 1 and 100 molecules of cloned-DNA of herpesviruses prototype strains were achieved. The RT multiplex PCR method proved capable of detecting enteroviral RNA or herpesviral DNA in cerebro spinal fluid (CSF) samples from patients with aetiologically well characterized encephalitis or aseptic meningitis.