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PubMed1983

Primary viraemia responses of herons to experimental infection with Murray Valley encephalitis, Kunjin and Japanese encephalitis viruses.

Rufous night herons, Pacific herons, little egrets and intermediate egrets were experimentally infected with Murray Valley encephalitis, Kunjin or Japanese encephalitis viruses. Viraemias of at least one day's duration were detected in all birds except two intermediate egrets inoculated with a very low dose of Kunjin virus and one rufous night heron inoculated with Japanese encephalitis virus. there was usually a viraemia of 3 to 5 days' duration commencing on the first or second day and continuing until day 5 or 6 and rarely until day 7. Maximum titres tended to be higher in young birds, up to 2-5 months of age (10(4)-10(5) mouse LD50/ml), than in older birds more than 8 months of age (10(3)-10(4) mouse LD50/ml). Significant differences in maximum viraemia titres were not observed in the different species or between Murray Valley encephalitis and Kunjin viruses. Japanese encephalitis viraemias were significantly lower, but this was probably due to the high mouse brain passage level of the strain used. The onset of viraemia was earlier in intermediate egrets than in rufous night herons inoculated with similar doses of Murray Valley encephalitis virus, but no difference in the susceptibility to infection was observed. With Kunjin virus there was a significant difference in the susceptibility of intermediate egrets and rufous night herons, with rufous night herons being more susceptible to infection with low doses of virus. This difference in threshold of infection, if it extends to other species with both Kunjin and Murray Valley encephalitis viruses, may, in part, be an explanation for the greater incidence of natural infections observed in rufous night herons compared with other species and orders of water birds.

Animals↗
PubMed1983

The caprine arthritis-encephalitis virus is a distinct virus within the Lentivirus group.

The genetic relatedness among viral genomes of caprine arthritis-encephalitis virus, visna virus, and progressive pneumonia virus, was determined. Whereas the genomic RNAs of two strains of visna virus are indistinguishable as reflected both by their annealing kinetics as well as by the thermal stability of the hybrids, the caprine arthritis-encephalitis virus and visna virus have only 30% of their nucleic acid sequences in common. Furthermore, within the homologous regions of the two viral genomes, there is a significant level (approximately 10%) of mismatched base pairs. This limited homology that exists between caprine arthritis-encephalitis virus and visna virus was lower than the sequence homology observed between the genomes of visna virus and progressive pneumonia virus, or between the genomes of caprine arthritis-encephalitis virus and progressive pneumonia virus. All this indicates that caprine arthritis-encephalitis virus is an additional distinct member of the Lentivirus group of the Retroviridae family.

Animals↗
PubMed1994

Analysis of virus-cell binding characteristics on the determination of Japanese encephalitis virus susceptibility.

The susceptibility of fourteen established cell lines to infection with Japanese encephalitis virus (JEV) was assayed using an indirect fluorescent antibody technique. In kinetic studies, the degree of binding and internalization of JEV allowed the identification of high susceptibility and low-susceptibility cells. Scatchard analysis showed that JEV specifically bound to high-susceptibility Vero cells with greater affinity than to low-susceptibility NRK cells. Microinjection of viral genomic RNA into NRK cells induced highly efficient production of viral antigen and infectious virions. A hemagglutinin-inhibiting monoclonal antibody against JEV (MAb 301) inhibited the binding of JEV to the Vero and NRK cells. JEV was found to bind to a 74K molecule present in the membrane fraction of Vero cells and this binding was inhibited by MAb 301. Importantly, the 74K molecule was not detected in the membrane faction of NRK cells. These results suggest that early events in the JEV-cell interaction influence the susceptibility of cells to infection, and in particular suggests that the 74K molecule may be a possible candidate or component of the cellular receptor for JEV.

Animals↗
PubMed2001

Biphasic illness pattern due to early relapse in Japanese-B virus encephalitis.

Japanese-B virus encephalitis (JE) is considered a uniphasic illness with a variable outcome. Biphasic illness patterns have never been reported previously. From an endemic zone in India we observed six patients of JE (from 62 patients treated in 7 years) who had an early relapse resulting in the biphasic clinical course. Five had poor socio-economic status and three had laboratory evidence of nutritional deficiency. Two patients were adults and the other four were children. Fever, rigors, headaches, body aches, altered consciousness, rigidity and tremors predominated the first phase of illness. During the second phase, behavioural changes, dystonia, pen-oral dyskinesia, drooling, mutism and muscle wasting due to anterior horn cell involvement were the important features. Though the serial antibody titres against the JE virus showed a four-fold rise in the initial or late convalescent phases, there was no increase during the second phase of the illness as compared to the first phase. On MRI, fresh lesions appeared during the second phase at the sites known for their involvement in JE, suggesting recrudescence of the virus. One patient survived with major sequelae, two with minor sequelae and the other three had complete recovery. We conclude that some patients with JE may have an early relapse after partial recovery, giving rise to the biphasic illness pattern. A locally prevalent genetic variant of the virus or host factors may be responsible for the altered clinical course of the disease. Biphasic illness does not necessarily mean a bad prognosis.

Adolescent↗
PubMed2004

Aerosol infection of cynomolgus macaques with enzootic strains of venezuelan equine encephalitis viruses.

Because Venezuelan equine encephalitis viruses (VEEVs) are infectious by aerosol, they are considered to be a biological-weapons threat. Nonhuman-primate models are needed to evaluate the efficacy of candidate vaccines. In the present study, cynomolgus macaques, after aerosol exposure to either VEEV-IE or VEEV-IIIA, developed fever, viremia, and lymphopenia; the severity of the fever response, viremia, and lymphopenia correlated with the inhaled dose of VEEV. Of the 10 macaques in our study, 7 developed clinical signs indicative of encephalitis, including loss of balance and hypothermia. In the macaque, the enzootic strains used are infectious by aerosol and lead to disease, including clinical encephalitis.

Aerosols↗
PubMed2025

Proteome Profiling in Cerebrospinal Fluid Reveals Increased Levels of Peroxiredoxin 2 Discriminating Japanese Encephalitis Virus and Scrub Typhus Infection.

Japanese encephalitis virus (JEV) and scrub typhus (ST) are major etiological agents of acute encephalitis syndrome (AES) in India and South Asia. The pathophysiological changes at the molecular level caused by JEV and ST have yet to be studied in detail. The cerebrospinal fluid (CSF) proteomic landscape is a critical indicator of CNS pathology. Here, we conducted label-free quantitative proteomics on CSF from AES patients (n = 15) to identify etiology-specific differentially expressed proteins (DEPs) linked to encephalitis. The key DEPs were validated via ELISA in CSF (n = 49) and serum (n = 33). Our findings revealed 50 proteins exhibited differential expression across JEV and ST groups, with a notable subset of three proteins, PRDX2, KLK6, and TTR. PRDX2 and KLK6 were markedly elevated in JEV CSF (AUC: 0.8933 and 0.9689) but not in ST or non-JEV AES, while TTR was reduced in JEV yet elevated in ST (AUC: 0.5619 vs. 0.8238). Further, PRDX2 upregulation was validated in JEV-infected mouse brains and cortical neurons. Overexpression of PRDX2 in human neuroblastoma cells correlated with enhanced antiviral gene expression, p-STAT1, p-AKT (ser473), and viral replication. Thus, our comprehensive proteomic analysis of CSF identifies PRDX2 as an important circulatory protein, differentially expressed between JEV and ST, with high specificity and enhancing viral propagation, underscoring its role in viral propagation and pathogenesis.

Humans↗
PubMed1999

Characterization of the immunodominant cross-reacting epitope of visna maedi virus and caprine arthritis-encephalitis virus capsid antigen.

Maedi visna (MV) and caprine arthritis-encephalitis (CAE) are two retroviral infections distributed world wide. Antigenic cross reactions between the viruses have been demonstrated in gag and env encoded structural proteins. Antigens from ovine lentiviruses are easier to produce in cell culture systems and therefore have been used in the development of diagnostic tests for both infections. Antigenically relevant epitopes have been characterised in the transmembrane protein, but little information is available on the immunodominant and cross reacting epitopes in the major capsid antigen (p25). In this study four different recombinant subunits of ovine lentivirus p25 were tested against sera from infected goats and a detailed characterisation of the immunodominant subunit was carried out. Highest ELISA absorbances were obtained with a 29 amino acid subunit located in the N'-terminal half of p25. Through the analysis of overlapping peptides spanning this region we identified a 17 amino acid sequence that can be used in the development of a highly standardized synthetic peptide-based assay.

Amino Acid Sequence↗
PubMed1974

Cross-protection between group B arboviruses: resistance in mice to Japanese B encephalitis and St. Louis encephalitis viruses induced by Dengue virus immunization.

Albino Swiss mice, immunized with any of several types and strains of dengue viruses, were afforded substantial protection against peripheral Japanese B encephalitis or St. Louis encephalitis virus challenge. Dengue-2 (New Guinea "C")-immunized mice showed, 10 and 20 weeks after immunization, undiminished resistance with concomitant cyclophosphamide treatment and virus challenge. Examination of the effects of immunization on Japanese B encephalitis virus pathogenesis, after virus challenge with concomitant cyclophosphamide treatment, indicated that protection was associated with decreased viremia and virtually no virus replication in the brain as compared with controls. These effects could be demonstrated before detection of any neutralizing antibody to the challenge virus. From the applied aspect, the data support the hypothesis, based on epidemiological evidence and experiments in hamsters, that prior exposure of man to dengue viruses can confer some degree of protection against Japanese B encephalitis or St. Louis encephalitis disease.

Animals↗
PubMed1989

Characterization of the local and systemic B cell response of normal and athymic nude mice with Sindbis virus encephalitis.

During Sindbis virus (SV) encephalitis in mice B cells are an important component of the mononuclear inflammatory response and recovery depends primarily on the development of antiviral antibody. To begin to characterize various parameters of the local B cell response during SV encephalitis we have defined B cell isotype expression in brain sections, splenocytes and peripheral blood mononuclear cells (PBMC) in normal and athymic nude mice using an immunoperoxidase technique. Early (days 3-5) in SV encephalitis brain perivascular B cells are IgM or IgM/IgD-bearing lymphocytes, later (days 10-14) most B cells express one of the IgG isotypes or IgA. The pattern of isotype expression seen in the brain during the course of the encephalitis is reflected in the spleen and blood. The data suggest that progressive isotype switching results in an increasingly higher percentage of certain isotypes, especially IgG2a. Isotype switching of most B cells may occur outside of the brain, or may arise in situ from the IgM/IgD-bearing B cells found in the brain throughout the course of encephalitis. In athymic nude mice numbers of B cells in brain were markedly decreased and the cells present were primarily IgM-bearing, although IgG isotypes and IgA did appear late (day 14). The data suggest that T cells are required for recruitment of B cells into the inflammatory response as well as for normal isotype switching and peripheral B cell maturation during SV encephalitis.

Animals↗
PubMed1990

Alterations in iron levels in Japanese encephalitis virus infection.

Following Japanese encephalitis virus (JEV) infection in mice the serum iron concentration decreased; the decline started from day 3 and persisted up to day 9 postinfection. No significant difference was found in the total iron-binding capacity of serum in JEV-infected mice compared with that of controls. The hypoferraemia was associated with accumulation of iron in the spleen. Large amounts of stainable iron were demonstrated in splenic macrophages from day 5. This was accompanied by transient anaemia. Thus, the hypoferraemia, following intraperitoneal inoculation of JEV, was attributed to a block in the release of iron from the RES.

Animals↗
PubMed2005

West Nile virus infection and serologic response among persons previously vaccinated against yellow fever and Japanese encephalitis viruses.

It is hypothesized that previous heterologous flaviviral exposure may modulate clinical illness among persons infected with West Nile virus (WNV). Little is known about the serological response in such persons. In summer 2003, a WNV outbreak occurred in Colorado, the location of the Centers for Disease Control and Prevention, Division of Vector-Borne Infectious Diseases (DVBID). DVBID employees, most previously vaccinated with yellow fever virus (YFV) or Japanese encephalitis virus (JEV) vaccines, were studied to determine whether previous vaccination affected symptom development among those subsequently infected with WNV during the outbreak, as well as their serological response. Serum samples collected in December 2003 and previously banked samples were tested using the plaque reduction neutralization test (PRNT) against WNV, Saint Louis encephalitis virus, dengue- 4 virus, JEV, and YFV. Specimens shown to have WNV antibody by PRNT were tested by IgM and IgG enzymelinked immunosorbent assays (ELISAs). Ten (9%) of 113 serosurvey participants had WNV neutralizing antibody titers in December 2003. PRNT titers from previous specimens showed that one of the ten had seroconverted to WNV before 2003. Of the remaining nine participants, seven reported illness in the summer of 2003, two of which were unvaccinated and five previously vaccinated. In the December 2003 specimens, five persons previously unvaccinated or vaccinated only against YFV had a fourfold or greater neutralizing titer with WNV than with other flaviviruses, whereas no persons previously vaccinated against JEV or JEV and YFV showed a similar difference in neutralizing titers. Eight of nine persons infected in 2003 had negative or indeterminate WNV MAC-ELISA results in the December 2003 sample; the ninth person was vaccinated against YFV one month previously, and was also YFV positive by MAC-ELISA. We conclude that previous flaviviral vaccination does not markedly affect the development of WNV fever and that the IgM antibody response in patients without neuroinvasive WNV disease is transient.

Adult↗
PubMed2005

Evaluation of combination therapy using aciclovir and corticosteroid in adult patients with herpes simplex virus encephalitis.

OBJECTIVE: Herpes simplex virus encephalitis (HSVE) is associated with significant morbidity and mortality, even with appropriate antiviral therapy. In the present investigation, the first to assess efficacy of corticosteroid treatment with aciclovir therapy in HSVE, multiple logistic regression analysis was performed of predictors of outcome in adult patients with HSVE. METHODS: A non-randomised retrospective study of 45 patients with HSVE treated with aciclovir was conducted. The patients were divided into poor and good groups based on outcome at three months after completion of aciclovir treatment. The variables evaluated were: clinical variables (sex, age, days after onset at initiation of aciclovir, Glasgow Coma Scale (GCS) at initiation of aciclovir, initial and maximum values for the cell numbers and protein concentration in the cerebrospinal fluid, and corticosteroid administration); neuroradiological variables (detection of lesions by initial cranial computed tomography and by initial magnetic resonance imaging); and one neurophysiological variable (detection of periodic lateralised epileptiform discharges on the initial electroencephalogram). Single variable logistic regression analysis was performed followed by multiple logistic regression analysis. The best set of predictors for the outcome of HSVE was estimated by stepwise logistic regression analysis. RESULTS: A poor outcome was evident with older age, lower GCS score at initiation of aciclovir, and no administration of corticosteroid. Patient age, GCS at initiation of aciclovir, and corticosteroid administration were found to be significant independent predictors of outcome on multiple logistic regression analysis, and these three variables also formed the best set of predictors (R(2) = 0.594, p<0.0001). CONCLUSION: Combination therapy using both aciclovir and corticosteroid represents one of the predictors of outcome in HSVE.

Acyclovir↗
PubMed1994

Protection elicited by a replication-defective adenovirus vector expressing the tick-borne encephalitis virus non-structural glycoprotein NS1.

Tick-borne encephalitis virus (TBEV) encodes a conserved, immunogenic, non-structural protein NS1 that is glycosylated and secreted from infected cells in an oligomeric form. An adenovirus recombinant, RAd51, expressing high levels of TBEV NS1 has previously been demonstrated to protect mice against a lethal challenge with TBEV. We show here that BALB/c mice infected with TBEV experienced a transient viraemia between days 3 to 5 post-inoculation that was detectable prior to the encephalitic phase of infection. Mice vaccinated with RAd51 were protected against both the viraemic and encephalitic infections associated with the TBEV challenge. Protection was demonstrated to be due to NS1 synthesized de novo from RAd51 in the vaccinated mice. Since TBEV NS1 is expressed on the cell surface, antibody-dependent complement-mediated cytolysis (CMC) of infected cells was considered as a possible mechanism of protection. Vaccination with the recombinant adenovirus proved to be effective in a mouse strain carrying a genetic deletion in the complement receptor C5. CMC is therefore not an essential component of the observed protective immune response.

Adenoviridae↗
PubMed2000

Secretion of the chemokine interleukin-8 during Japanese encephalitis virus infection.

Japanese encephalitis (JE) virus infection induces infiltration of neutrophils in neural as well as extraneural tissues in patients. As interleukin-8 (IL-8) has inflammatory properties, the present study was undertaken to investigate the IL-8 concentrations in cerebrospinal fluid (CSF) and serum from patients with JE and correlate them with neutrophil counts. IL-8 was measured in the CSF or serum of 30 patients with confirmed JE. The majority (92%) of the acute CSF samples showed raised levels of IL-8 with raised numbers of polymorphonuclear leucocytes. Similarly, significantly higher serum IL-8 concentrations were detected in the acute phase of illness than in convalescent JE patients or normal healthy controls. Twenty-one of 25 patients with high concentrations of IL-8 showed significantly increased neutrophil counts in acute phase sera. A gradual decline in neutrophil counts was observed in the convalescent phase of patients who recovered. There was a significant correlation between IL-8 level and the severity of illness, as all severely ill and fatal cases showed higher levels of IL-8 in acute CSF or serum than the levels found in those who recovered. IL-8 concentrations remained high for a longer period in patients with prolonged severe illness than in those who made a complete recovery.

Acute Disease↗
PubMed2001

Complete nucleotide sequence and cell-line multiplication pattern of the attenuated variant CH2195LA of Japanese encephalitis virus.

Strain-specific determinant of Japanese encephalitis virus (JEV) can be different among each virulence phenotype. We reported previously that the attenuated variant CH2195LA compared with the non-attenuated variant CH2195SA had four amino acid differences in E protein (E-85, E-306, E-331, and E-387) (Wu, S.-C., Lian, W.-C., Hsu, L.-C., Liau, M., 1997. Japanese encephalitis virus antigenic variants with characteristic differences in neutralization resistance and mouse virulence. Virus Res. 51, 173-181). Our present study determined the complete nucleotide sequences of these two variants and found another five amino acid changes in the nonstructural gene regions, including NS2A-215, NS3-350, NS4B-196, NS4B-197, and NS4B-198. The complete nucleotide sequences of the attenuated variant CH2195LA were compared with the non-attenuated variant CH2195SA and other 13 JEV strains. CH2195LA was mostly close to CH2195SA and JaOArS982, and phylogenetically distant to SA14-14-2, SA14-2-8, and RP-2ms of the attenuated JEV strains. The multiplication patterns for CH2195LA compared with CH2195SA in other seven cell lines were different from Vero cells. Relative fitness vector analysis based on a mixture of both variants during cell passage indicated the attenuated variant CH2195LA showed increased viral fitness in Vero cell adaptation. These results revealed that the attenuated variant CH2195LA was unique to culture in Vero cells.

Amino Acid Substitution↗
PubMed1996

The patterns of varicella zoster virus encephalitis.

Varicella zoster virus (VZV) encephalitis has become increasingly prevalent in the era of acquired immunodeficiency syndrome (AIDS), and a widening spectrum of pathological lesions has defined the disease in these and other severely immunosuppressed patients. VZV produces three distinct morphological patterns of brain damage. VZV can cause bland or hemorrhagic infarctions secondary to a large or medium vessel vasculopathy. Deep white matter, ovoid mixed necrotic, and demyelinative lesions occur as a consequence of small vessel vasculopathy, with demyelination dependent on the degree of additional oligodendrocyte infection. Distinctive Cowdry A intra-nuclear viral inclusions are rare in either large or small blood vessels or near infarctions, but are commonly found in glial cells at the edge of the smaller ovoid, demyelinative lesions. Ependymal and periventricular necrosis occurs as a result of vasculopathy of subependymal vessels and secondary infection of ependymal and other glial cells in the periventricular region. To clarify these patterns of VZV encephalitis and shed light on their pathogenesis, the authors have examined all cases of VZV encephalitis seen at our institution since 1984. Additionally, the authors review the extensive literature in an attempt to classify the patterns of VZV encephalitis into (1) large/ medium vessel vasculopathy with bland or hemorrhagic infarctions, (2) small vessel vasculopathy with mixed ischemic/demyelinative lesions, and (3) ventriculitis/periventriculitis. Although one of these three patterns often predominates clinically and radiographically, careful histological examination at autopsy shows mixed features in many cases.

AIDS-Related Opportunistic Infections↗
PubMed1991

Persistent infection of Vero cells by the flavivirus Murray Valley encephalitis virus.

Murray Valley encephalitis (MVE) virus strain OR2 was serially passaged on Vero cells to establish a persistent infection which was maintained for over 300 days. Supernatants from infected cells protected Vero cells from c.p.e. and caused up to a 95% reduction of wild-type virus yield. These protective and interfering effects suggest that defective interfering (DI) particles are responsible for the establishment and maintenance of the MVE virus persistent infection. The persistently infected cell supernatant preparations shared several features with DI particle preparations from other viral systems, such as their amplification to detectable levels after two to four passages of virus. However, results from this study suggest that DI particles of MVE virus differ from other studied systems in that they are able to affect only moderately the yield of infectious wild-type virus. The genetic drift of the parental virus during the course of a long term persistent infection in vitro appears to be minimal.

Animals↗