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PubMed1986

[Encephalization of the marine lamprey, Petromyzon marinus (L.). Quantitative analysis of the principle brain subdivisions].

The measure of both the somatic weight (S) and the brain weight (E) on a sample of 13 adult individuals of Petromyzon marinus (L.) leads for this species to the determination of its brain-body weight coefficient of allometry and to the knowledge of its index of encephalization. The value of the first one is 0.556. Its locates the Sea-Lamprey at the highest level of a scale of decreasing values belonging one after the other to Chondrichthyes (0.551), to Teleost fishes (0.487), to Anurans (0.458), to Reptiles (0.43) and at last to Mammals (0.25). This result revalues our previous hypothesis which gives to this kind of statistic a phylogenetic meaning (RIDET et al. 1977). The index of encephalization has been arbitrarily fixed at the 10 value; it is the lowest of all the other indices previously known and consequently it points the Sea-Lamprey as the less encephalized Vertebrate species. The histological study carried out on the brain allows to the knowledge of the volumes of the main encephalic subdivisions. It leads to various results as: 1. The study the relative volumes (that is to say the volume of each subdivision expressed in percentage of the volume of the whole brain) emphasizes the olfactory bulbs and the Tegmentum + Medulla oblongata which have together the highest values amongst the brain percentages of Petromyzon marinus (and also of Lampetra planeri). This peculiarity has no equivalence in the brain structure of the other studied species of Vertebrates and we consider it as the expression of a primitive brain pattern. 2. The isoponderal indices locate also the Sea-Lamprey at the lowest level for all its encephalic subdivisions, as it was previously the case for the whole brain expressed by the index of encephalization. Such an unanimity seems also to be related to a fundamental brain organization. Comparisons between Petromyzon marinus, Lampetra planeri and Myxine glutinosa corroborate the paraphyletic status of the last one in the Agnathes. The differences pointed also between the two first species are less obvious but justify meanwhile a more detailed study of this group (Petromyzontidae) which shall be given soon.

Animals↗
PubMed2007

Proinflammatory mediators released by activated microglia induces neuronal death in Japanese encephalitis.

While a number of studies have documented the importance of microglia in central nervous system (CNS) response to injury, infection and disease, little is known regarding its role in viral encephalitis. We therefore, exploited an experimental model of Japanese Encephalitis, to better understand the role played by microglia in Japanese Encephalitis Virus (JEV) infection. Lectin staining performed to assess microglial activation indicated a robust increase in reactive microglia following infection. A difference in the topographic distribution of activated, resting, and phagocytic microglia was also observed. The levels of various proinflammatory mediators, such as inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (Cox-2), IL-6, IL-1beta, TNF-alpha, and MCP-1 that have been implicated in microglial response to an activational state was significantly elevated following infection. These cytokines exhibited region selective expression in the brains of infected animals, with the highest expression observed in the hippocampus. Moreover, the expression of neuronal specific nuclear protein NeuN was markedly downregulated during progressive infection indicating neuronal loss. In vitro studies further confirmed that microglial activation and subsequent release of various proinflammatory mediators induces neuronal death following JEV infection. Although initiation of immune responses by microglial cells is an important protective mechanism in the CNS, unrestrained inflammatory responses may result in irreparable brain damage. Our findings suggest that the increased microglial activation following JEV infection influences the outcome of viral pathogenesis. It is likely that the increased microglial activation triggers bystander damage, as the animals eventually succumb to infection.

Animals↗
PubMed1996

Molecular characterization of the Japanese encephalitis serocomplex of the flavivirus genus.

The Japanese encephalitis (JE) serocomplex of flaviviruses comprises 10 members, 9 of which: Alfuy (ALF); Koutango (KOU); Kokobera (KOK); Kunjin (KUN); Murray Valley encephalitis (MVE); JE; Stratford (STR); Usutu (USU); and West Nile (WN) have been isolated from Africa, southern Europe, Middle East, Asia, and Australia. The tenth member, St. Louis encephalitis (SLE) virus, is confined to North, Central, and South America. For ALF, KOK, KOU, STR, and USU, no sequence data have as yet been reported, and little molecular phylogeny has been determined for this complex as a whole. Using a rapid, one-step RT-PCR and universal primers, we have amplified and sequenced a 450-600 base pair region of the virus genome encompassing the N terminus of the nonstructural protein NS5 and the 5' end of the 3' noncoding region, for several strains of all of these viruses, except USU and SLE viruses. These data, as well as published sequence data for other flaviviruses, were analyzed with the ClustalW and Phylip computer packages. The resultant phylogenetic data were consistent with some of the current flavivirus serological classification, showing a close relationship between ALF and MVE viruses and between KOK and STR viruses, but suggested that KOK and STR are distantly related to the other viruses and should perhaps be reclassified in their own serocomplex. The data also confirmed the close relationship between KUN and WN viruses and showed that an isolate of KUN virus from Sarawak may represent a "link" between these two virus species. In addition, the primary sequence data revealed a polymorphic region just downstream of the stop codon in the 3' end of the viral genomes.

Amino Acid Sequence↗
PubMed1978

Morphological demonstration of the virus of tick-borne encephalitis in the human brain.

A case is presented in which the fourfold increase of the HI titer during the progression of the disease, and an increase in IgM content found at the beginning of the second week of the disease confirmed the diagnosis of tick-borne encephalitis. The light microscopic changes correspond to the findings accepted as characteristic to tick-borne encephalitis. Viruses, morphologically belonging to the Flavivirus genus were found by electron microscopy in the thalamus, substantia nigra, and cerebellum of the dissected brain. This paper presents the first demonstration of the virus in a case of a human tick-borne encephalitis.

Adult↗
PubMedDate not supplied

Experimental encephalitis in monkeys caused by the Powassan virus.

We have carried out a comparative study of the experimental infection of monkeys with the P-40 strain of the Powassen virus, isolated in the Primor'e Territory of the USSR, and with the Canadian prototype LB strain. The Powassan virus was found to be pathogenic for Macaca rhesus. The clinical and pathomorphological picture of the experimental encephalitis was studied, and the full identity of the infection produced in the monkeys by the P-40 strain and the Canadian LB strain of the Powassan virus was demonstrated. On electron microscopic examination of the central nervous system the virus was detected in the neurons, glial cells, and intercellular spaces. The virions of the strains studied have identical morphological parameters, being 37-45 nm in diameter and of spherical shape. The data obtained indicated a marked neurotropism of the virus. They will contribute to the elucidation of the role of the virus in the infection pathology of humans, i.e., in the differentiation of encephalitis cases not associated etiologically with the virus of the spring-summer tickborne encephalitis.

Animals↗
PubMedDate not supplied

Acute disseminated encephalomyelitis after Japanese B encephalitis vaccination.

A 6-year-old girl (Patient 1) and a 5-year-old boy (Patient 2) with acute disseminated encephalomyelitis after Japanese B encephalitis vaccination are reported. Drowsiness, paresthesias, and gait disturbance were observed at 14 days (Patient 1) and 17 days (Patient 2) after the vaccination; however, transient impairment of visual acuity was only found in Patient 1. Laboratory examinations revealed slow theta waves on electroencephalography and elevated myelin basic protein in the cerebrospinal fluid in both patients. The most striking feature on magnetic resonance imaging was the combination of white matter lesions and abnormal intensity signals of the thalamus. The administration of oral prednisolone (2 mg/kg/day) markedly improved the clinical findings and abnormal magnetic resonance imaging findings. A similar magnetic resonance imaging finding of abnormal intensity of the thalamus with deep white matter lesions has been reported in patients with Japanese B encephalitis; therefore, thalamic lesions may be related to the naturally occurring encephalitis.

Child↗
PubMed1994

Predictive factors of short-term neurologic outcome in children with encephalitis.

When a child is admitted to the hospital with presumed encephalitis, the physician must use clinical criteria to gauge the appropriate level of hospital care and to give a preliminary assessment of outcome to the family because the etiology is unknown. This study attempted to determine which clinical factors gathered on hospital admission would be most helpful to the physician. The records of 106 children (ages 1 month to 20 years), admitted to Rainbow Babies and Childrens Hospital between 1978-1989 who had discharge diagnoses of encephalitis, were reviewed. Seventy-five met the case definition of presumed viral encephalitis, with viral etiology established in 23% of patients. Poor short-term outcome was defined as the presence of an abnormal neurologic examination at hospital discharge, and was present in 32% of patients. Focal signs on neurologic examination (odds risk: 16.30, P < .05) and abnormal neuroimaging studies (odds risk: 5.66, P < .05) were the only 2 factors present at admission that predicted a poor short-term outcome. Glasgow coma scale at admission was predictive of an abnormal neurologic examination at discharge only when profoundly depressed (6 or less); otherwise, this scale was not useful as a prognostic tool. Factors that were not correlated with adverse outcomes included age younger than 1 year, any type of seizure occurrence, status epilepticus, diffuse or focal electroencephalographic abnormalities, or abnormal cerebrospinal fluid findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Serological evidence for Japanese encephalitis and West Nile viruses in domestic animals of Nepal.

A regional survey was conducted in Nepal for antibody to Japanese encephalitis virus (JEV) in domestic animals. Sera from pigs, and limited numbers of ducks and horses were collected from 16 districts in 2002-2003 and subjected to three serological tests. Of 270 porcine sera tested by C-ELISA, 55% were found positive for the presence of antibodies against Japanese encephalitis virus. Additional testing for IgM antibody to JEV revealed less than 2% of C-ELISA positive sera had evidence of recent JEV infection. Plaque reduction neutralisation tests (PRNT) using JEV, Murray Valley encephalitis (MVEV) and Kunjin (KUNV) viruses implicated JEV as the flavivirus associated with the observed antibody response in most sero-positive pigs. However, eight porcine sera with predominant neutralising antibody for KUNV (an Australasian subtype of West Nile Virus) provided evidence for the circulation of West Nile virus in Nepal.

Animals↗
PubMed2006

Development of an enzyme-linked immunosorbent assay for serological diagnosis of tick-borne encephalitis using subviral particles.

The similarity of symptoms produced by tick-borne encephalitis (TBE) and Japanese encephalitis (JE) and the high degree of cross-reactivity between TBE and JE viruses by serological tests make the development of a differential diagnostic test a priority. In this study, recombinant prM/E proteins of TBE virus strain Oshima 5-10 expressed in mammalian cells resulted in the release of subviral particles (SPs) into the culture medium. Using the SPs as antigens, enzyme-linked immunosorbent assay (ELISA) systems were developed to detect TBE virus-specific IgM and IgG antibodies, designated SP-IgG and SP-IgM ELISAs, respectively. Of 83 serum samples from encephalitis patients in Khabarovsk, Russia, which were positive with the neutralization test (NT), 82 were positive by the SP-IgG ELISA, for a sensitivity of 98.8%, which was higher than that of a commercial ELISA kit. All 12 NT-negative samples were also negative by the SP-IgG ELISA (specificity, 100%). Of 17 patient samples that were NT-positive, 16 (94.1%) were positive by the SP-IgM ELISA. Of 15 paired serum samples that yielded equivocal results by NT, 11 had positive results with the SP-IgM ELISA, indicating a diagnosis of TBE infection. The SP-IgG and SP-IgM ELISAs showed no cross-reactivity with antibodies to the JE virus. The results indicate that these ELISAs will be useful for the detection of TBE-specific antibodies.

Animals↗
PubMed2004

Construction of recombinant pseudorabies virus expressing NS1 protein of Japanese encephalitis (SA14-14-2) virus and its safety and immunogenicity.

The bivalent genetic engineering vaccine of Japanese encephalitis (JE) and Aujeszkj disease (AD) was developed to provide a novel approach to prevent and control these two diseases. NS1 gene of Japanese encephalitis virus (JEV) SA14-14-2 strain was produced by reverse transcriptase-mediated PCR (RT-PCR) and was cloned into vector pUSK to form recombinant plasmid (designed as pUSK-NS1). A co-transfection experiment was performed in porcine kidney (PK-15) cells with pUSK-NS1 and the genome of the vector virus (PRV TK(-)/gG(-)/LacZ(+) mutant). By plaque purification, PCR detection and southern hybridization, recombinant pseudorabies virus (PRV) expressing NS1 protein of JEV was acquired and named TK(-)/gG(-)/NS1(+). Western blot analysis and ELISA demonstrated the NS1 protein expression. To evaluate the recombinant virus's potential application, we characterized the safety and immune responses in Balb/c mice and swine. The safety test indicated that, when receiving the recombinant virus at a concentration of 10(6.0)pfu, no virulence of the recombinant virus to the mice, piglets and pregnant sows was observed. The vaccinated animals could acquire protective immunity against lethal challenge of the virulent PRV Ea strain and develop a good humoral and cellular immune response against JEV. The above results revealed that the recombinant virus could be a suitable candidate vaccine strain for developing a novel genetic vaccine to combat pseudorabies and Japanese encephalitis in the pig industry.

Animals↗
PubMedDate not supplied

Effect of single dose of SA 14-14-2 vaccine 1 year after immunisation in Nepalese children with Japanese encephalitis: a case-control study.

BACKGROUND: In July, 1999, a single dose of live-attenuated SA 14-14-2 Japanese encephalitis vaccine was given to children aged 1-15 years in the Terai region of Nepal. Cases of natural infection occurred almost immediately. Our aim was to assess the long-term protective effect of this vaccination. METHODS: In 2000, this same population had a second seasonal exposure to the virus. We therefore did a case-control study to measure the prevalence of vaccination against Japanese encephalitis in 35 patients hospitalised for the disease 1 year after immunisation, and in age-sex matched village controls. FINDINGS: Of 35 children resident in Bardiya and Banke districts admitted to the Bheri Zonal Hospital with serologically confirmed Japanese encephalitis, only one had been vaccinated in 1999. In 430 age-sex matched village controls, 234 (54.4%) were vaccinated. We calculated a median unbiased estimate of the odds ratio of 0.0155, with lower and upper confidence limits of 0.0004 and 0.0986. The protective effect of vaccine after 12-15 months was 98.5% (CI 90.1-99.2%). INTERPRETATION: Our study provides evidence of sustained high protection afforded by one dose of live attenuated SA 14-14-2 vaccine in Nepalese children.

Adolescent↗
PubMed2001

Amplification and cloning of the full-length genome of Japanese encephalitis virus by a novel long RT-PCR protocol in a cosmid vector.

A novel and rapid full-length long RT-PCR technique was established to produce genome-length cDNA from Japanese encephalitis virus. In vitro positive strand RNA transcripts from the full-length RT-PCR amplicon including T7 promoter sequences at the 5' end were proved to be infectious upon transfection. The full-length amplicon without the T7 promoter was cloned into a cosmid vector under the SP6 promoter. This stable clone, designated as pJEV-1, was characterised further and used as a genetic resource for generation of infectious RNA transcripts, gene manipulation and expression. The 'run-off' transcript from pJEV-1 with vector sequences at the either end of the insert was not infectious, but transcripts of the full-length PCR amplicon from pJEV-1 produced infectious virus upon transfection. A transcript with an engineered Xho I site from two ligated PCR fragments amplified from pJEV-1 was also infectious. Furthermore, the coding region for premembrane and envelope proteins (preM-E) from pJEV-1 was subcloned and expressed in the Drosophila Expression System. The expressed protein showed correct molecular size and was immunoreactive with a Japanese encephalitis virus E protein-specific antibody. The derivation of genome-size cDNA from Japanese encephalitis virus and the stable clone will facilitate investigation of this virus and elucidation of its pathogenesis at the molecular level.

Animals↗
PubMed1995

Thrombocytopenia, leukopenia and abnormal liver function tests in the initial phase of tick-borne encephalitis.

One-hundred-seventy-five patients in whom bone marrow puncture had been performed at the Department of Infectious Diseases, University Medical Centre, Ljubljana, during the period from 1988 to 1992, were analysed in a retrospective study. In five out of these 175 patients, tick-borne encephalitis virus infection was confirmed by serological tests and in all of them bone marrow puncture was performed in the initial phase of the illness as part of diagnostic work-up in a patient with a febrile illness accompanied by leukopenia and thrombocytopenia. Bone marrow examination revealed minimal reactive changes or normal findings. In addition to leukopenia and thrombocytopenia, abnormal liver function tests were also found in four patients. All these patients later developed meningoencephalitis, i.e. they had clinically typical tick-borne encephalitis with biphasic course of the illness. In the initial phase of tick-borne encephalitis in addition to well-known leukopenia, thrombocytopenia and abnormal liver function tests may be found.

Adult↗
PubMed2003

Detection of antibodies to alphaviruses and discrimination between antibodies to eastern and western equine encephalitis viruses in rabbit sera using a recombinant antigen and virus-specific monoclonal antibodies.

Three arthropod-borne alphaviruses, western equine encephalitis viruses (WEEV), eastern equine encephalitis viruses (EEEV) and Venezuelan equine encephalitis viruses are the aetiological agents of a sometimes severe encephalomyelitis in equines and humans in the New World. With regard to the different ecology and epidemiology of these viruses, a method applied in serological screening should be able to distinguish between them as well as other related members of the genus Alphavirus in the American continent. However, this has been hampered in the past by (a) the close antigenic relationship between alphaviruses in traditional serological assays, especially in the routinely used haemagglutination-inhibition, and (b) the need of biosafety level 3 facilities to grow the viral antigens. An epitope blocking assay using an EEEV glycoprotein E1-expressing recombinant Sindbis virus and virus-specific monoclonal antibodies (mAbs) binding to the E1 of EEEV (strain NJ/60) and the E1 of Sindbis virus was established using automated flow cytometry. The test was evaluated using sera of infected and vaccinated rabbits. A cut-off value of 30% inhibition for antigenic complex-specific seroconversion was found to be sufficient for the detection of the respective infection. By using three different mAbs in parallel, we were able to detect alphavirus genus-, EEEV- and WEEV-complex-specific serum antibodies. As this test is based on the inhibition of binding of virus-specific mAbs, sera of every origin other than mouse can be tested. Thus, this assay may prove useful in the serological screening of a variety of animal species during an outbreak investigation.

Animals↗
PubMed1988

Western equine encephalitis virus is a recombinant virus.

The alphaviruses are a group of 26 mosquito-borne viruses that cause a variety of human diseases. Many of the New World alphaviruses cause encephalitis, whereas the Old World viruses more typically cause fever, rash, and arthralgia. The genome is a single-stranded nonsegmented RNA molecule of + polarity; it is about 11,700 nucleotides in length. Several alphavirus genomes have been sequenced in whole or in part, and these sequences demonstrate that alpha-viruses have descended from a common ancestor by divergent evolution. We have now obtained the sequence of the 3'-terminal 4288 nucleotides of the RNA of the New World Alphavirus western equine encephalitis virus (WEEV). Comparisons of the nucleotide and amino acid sequences of WEEV with those of other alphaviruses clearly show that WEEV is recombinant. The sequences of the capsid protein and of the (untranslated) 3'-terminal 80 nucleotides of WEEV are closely related to the corresponding sequences of the New World Alphavirus eastern equine encephalitis virus (EEEV), whereas the sequences of glycoproteins E2 and E1 of WEEV are more closely related to those of an Old World virus, Sindbis virus. Thus, WEEV appears to have arisen by recombination between an EEEV-like virus and a Sindbis-like virus to give rise to a new virus with the encephalogenic properties of EEEV but the antigenic specificity of Sindbis virus. There has been speculation that recombination might play an important role in the evolution of RNA viruses. The current finding that a widespread and successful RNA virus is recombinant provides support for such an hypothesis.

Amino Acid Sequence↗
PubMed2000

Early diagnosis of Murray Valley encephalitis by reverse transcriptase-polymerase chain reaction.

A 4-year-old aboriginal boy developed encephalitis due to Murray Valley encephalitis virus (MVE) following an earlier infection with Kunjin virus (KUN). The illness was severe, resulting in cerebral atrophy and profound physical and intellectual disability. The earlier KUN infection complicated his serological profile and delayed antibody responses to MVE. By contrast, the reverse transcriptase-polymerase chain reaction (RT-PCR) assay detected MVE in serum 3 days after the onset of illness and 4 days before the appearance of MVE-specific IgM. We suggest that MVE-specific RT-PCR provides rapid and specific diagnosis of MVE and should be used more widely for the diagnosis of acute viral encephalitis in cases originating from flavivirus endemic areas.

Antibodies, Viral↗
PubMed2001

Varicella-zoster virus limbic encephalitis in an immunocompromised patient.

A case of limbic encephalitis in a patient who had undergone prolonged immunosuppressive treatment with i.v. cyclophosphamide and oral prednisolone for a microscopic polyangeitis is reported. A brain MRI scan revealed symmetric mesial temporal lobe lesions. Studies of cerebrospinal fluid (CSF) revealed a positive PCR for varicella-zoster virus (VZV) DNA in 2 separate samples. Owing to a delay in diagnosis, intravenous acyclovir was initiated only after 11 d of symptoms. PCR of CSF for VZV DNA became negative on day 14 of treatment while brain lesions had resolved on subsequent MRI scans. Limbic encephalitis is a novel form of VZV infection. When brain imaging is suggestive of limbic encephalitis in an immunocompromised patient, PCR of CSF for VZV DNA should be performed, as early antiviral treatment may improve the outcome.

Acyclovir↗
PubMed2002

Tick-borne encephalitis in north-eastern Poland in 1997-2001: a retrospective study.

The aim of this study was to characterize the epidemiology and clinical features of tick-borne encephalitis in north-eastern Poland. Clinical and epidemiological data were analysed of patients hospitalized with the diagnosis in the Department of the Infectious Diseases and Neuroinfections of the Medical University in Bialystok in 1997-2001. Tick-borne encephalitis was diagnosed in 152 patients: 51 (34%) presented with meningitis, 89 (59%) with meningoencephalitis and 12 (8%) with meningoencephalomyelitis. Headache (84%) and fever (81%) were the most common symptoms. Meningeal signs were present in 137 patients (90%). Most common neurological abnormalities were: Oppenheim and Babinski signs (74 patients, 49%), ataxia (37, 24%), impaired consciousness (37, 24%) and pareses (16, 10%). Of patients examined, 146 (96%) had raised pleiocytosis, frequently accompanied by high cerebrospinal fluid protein concentration (90%), raised erythrocyte sedimentation rate (65%), peripheral blood leucocytosis (26%) and increased aminotransferase activity (16%). There was only 1 forest worker among the patients. Tick-borne encephalitis remains common in north-eastern Poland but, possibly because of effective vaccination, it has virtually disappeared among forest employees. The diagnosis appears difficult in some cases, as meningeal signs may not be present and laboratory findings may not be suggestive of a viral infection.

Adolescent↗