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Veterinary Microbiology Jun 2024Japanese Encephalitis Virus (JEV), the predominant cause of viral encephalitis in many Asian countries, affects approximately 68,000 people annually. Lysosomes are...
Japanese Encephalitis Virus (JEV), the predominant cause of viral encephalitis in many Asian countries, affects approximately 68,000 people annually. Lysosomes are dynamic structures that regulate cellular metabolism by mediating lysosomal biogenesis and autophagy. Here, we showed that lysosome-associated membrane protein 1 (LAMP1) and LAMP2 were downregulated in cells after JEV infection, resulting in a decrease in the quantity of acidified lysosomes and impaired lysosomal catabolism. What's more, JEV nonstructural protein 4B plays key roles in the reduction of LAMP1/2 via the autophagy-lysosome pathway. JEV NS4B also promoted abnormal aggregation of SLA-DR, an important component of the swine MHC-II molecule family involved in antigen presentation and CD4 cell activation initiation. Mechanistically, NS4B localized to the ER during JEV infection and interacted with GRP78, leading to the activation of ER stress-mediated autophagy. The 131-204 amino acid (aa) region of NS4B is essential for autophagy induction and LAMP1/2 reduction. In summary, our findings reveal a novel pathway by which JEV induces autophagy and disrupts lysosomal function.
PubMed: 38861863
DOI: 10.1016/j.vetmic.2024.110150 -
Journal of Neurovirology Jun 2024
PubMed: 38858345
DOI: 10.1007/s13365-024-01220-z -
Journal of Neurovirology Jun 2024Japanese Encephalitis remains a significant global health concern, contributing to millions of deaths annually worldwide. Microglial cells, as key innate immune cells... (Review)
Review
Japanese Encephalitis remains a significant global health concern, contributing to millions of deaths annually worldwide. Microglial cells, as key innate immune cells within the central nervous system (CNS), exhibit intricate cellular structures and possess molecular phenotypic plasticity, playing pivotal roles in immune responses during CNS viral infections. Particularly under viral inflammatory conditions, microglial cells orchestrate innate and adaptive immune responses to mitigate viral invasion and dampen inflammatory reactions. This review article comprehensively summarizes the pathophysiology of viral invasion into the CNS and the cellular interactions involved, elucidating the roles of various immune mediators, including pro-inflammatory cytokines, in neuroinflammation. Leveraging this knowledge, strategies for modulating inflammatory responses and attenuating hyperactivation of glial cells to mitigate viral replication within the brain are discussed. Furthermore, current chemotherapeutic and antiviral drugs are examined, elucidating their mechanisms of action against viral replication. This review aims to provide insights into therapeutic interventions for Japanese Encephalitis and related viral infections, ultimately contributing to improved outcomes for affected individuals.
PubMed: 38842651
DOI: 10.1007/s13365-024-01212-z -
Virology Journal Jun 2024The envelope (E) protein of the Japanese encephalitis virus (JEV) is a key protein for virus infection and adsorption of host cells, which determines the virulence of...
The envelope (E) protein of the Japanese encephalitis virus (JEV) is a key protein for virus infection and adsorption of host cells, which determines the virulence of the virus and regulates the intensity of inflammatory response. The mutation of multiple aa residues in the E protein plays a critical role in the attenuated strain of JEV. This study demonstrated that the Asp to Gly, Ser, and His mutation of the E389 site, respectively, the replication ability of the viruses in cells was significantly reduced, and the viral neuroinvasiveness was attenuated to different degrees. Among them, the mutation at E389 site enhanced the E protein flexibility contributed to the attenuation of neuroinvasiveness. In contrast, less flexibility of E protein enhanced the neuroinvasiveness of the strain. Our results indicate that the mechanism of attenuation of E389 aa mutation attenuates neuroinvasiveness is related to increased flexibility of the E protein. In addition, the increased flexibility of E protein enhanced the viral sensitivity to heparin inhibition in vitro, which may lead to a decrease in the viral load entering brain. These results suggest that E389 residue is a potential site affecting JEV virulence, and the flexibility of the E protein of aa at this site plays an important role in the determination of neuroinvasiveness.
Topics: Encephalitis Virus, Japanese; Viral Envelope Proteins; Animals; Cell Line; Virulence; Virus Replication; Encephalitis, Japanese; Humans; Heparin; Amino Acid Substitution; Mutation, Missense; Mice; Mutation; Virulence Factors; Membrane Glycoproteins
PubMed: 38840203
DOI: 10.1186/s12985-024-02398-8 -
APMIS : Acta Pathologica,... Jun 2024Acute encephalitis syndrome (AES) is a major public health concern in India as the aetiology remains unknown in the majority of cases with the current testing algorithm....
Acute encephalitis syndrome (AES) is a major public health concern in India as the aetiology remains unknown in the majority of cases with the current testing algorithm. We aimed to study the incidence of Japanese encephalitis (JE) and determine the aetiology of non-JE AES cases to develop an evidence-based testing algorithm. Cerebrospinal fluid (CSF) samples were tested for Japanese encephalitis virus by ELISA and polymerase chain reaction (PCR). Multiplex real-time PCR was done for Dengue, Chikungunya, West Nile, Zika, Enterovirus, Epstein Barr Virus, Herpes Simplex Virus, Adenovirus, Cytomegalovirus, Herpesvirus 6, Parechovirus, Parvovirus B19, Varicella Zoster Virus, Scrub typhus, Rickettsia species, Leptospira, Salmonella species, Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, Plasmodium species and by ELISA for Mumps and Measles virus. Of the 3173 CSF samples, 461 (14.5%) were positive for JE. Of the 334 non-JE AES cases, 66.2% viz. Scrub typhus (25.7%), Mumps (19.5%), Measles (4.2%), Parvovirus B19 (3.9%) Plasmodium (2.7%), HSV 1 and 2 (2.4%), EBV and Streptococcus pneumoniae (2.1% each), Salmonella and HHV 6 (1.2% each) were predominant. Hence, an improved surveillance system and our suggested expanded testing algorithm can improve the diagnosis of potentially treatable infectious agents of AES in India.
PubMed: 38837462
DOI: 10.1111/apm.13443 -
Intractable & Rare Diseases Research May 2024The Japanese Research Group for Neuro-infectious Diseases was founded in August 1996, and by 2004 it had evolved into the Japanese Society for Neuro-infectious Diseases....
The Japanese Research Group for Neuro-infectious Diseases was founded in August 1996, and by 2004 it had evolved into the Japanese Society for Neuro-infectious Diseases. The Society focuses on neuroinfectious conditions (., encephalitis/encephalopathy, myelitis, and meningitis), providing a venue for academic presentations and exchanges. Clinical guidelines for major neurological infectious diseases are also published by the Society, in order to meet the social demands of each era. Although the threat of herpes simplex encephalitis has declined due to acyclovir's introduction, the frequency of encephalitis or peripheral neuropathy caused by varicella-zoster virus is increasing. In Japan, prion disease, human T-cell leukemia virus-1 (HTLV-1)-associated myelopathy (HAM), subacute sclerosing panencephalitis (SSPE), and progressive multifocal leukoencephalopathy (PML) are designated as intractable diseases. The incidence of prion disease is 1.8/1,000,000 individuals, with the sporadic type accounting for 80%. Prion disease is fatal, and effective medications are awaited. HAM's prevalence is ~3/100,000 individuals, with a male-to-female ratio of 1:2-3. HAM is common in western Japan, including Kyushu and Okinawa. The prevalence of PML is rising with the spread of both immunosuppressive therapy for transplantation and treatment for multiple sclerosis. From late 2019 through 2020, the world faced a global outbreak of coronavirus disease 2019 (COVID-19) due to virus mutations, and the threat of new mutations persists. Close attention should be paid to the emergence of new neurological infections that could arise from abnormal weather patterns and/or a decline in immune function due to aging.
PubMed: 38836177
DOI: 10.5582/irdr.2024.01008 -
Acta Tropica Aug 2024Culex gelidus (Diptera: Culicidae), an important vector of the Japanese encephalitis virus (JEV), contributes to human viral encephalitis in many Asian countries,...
Culex gelidus (Diptera: Culicidae), an important vector of the Japanese encephalitis virus (JEV), contributes to human viral encephalitis in many Asian countries, including Thailand. This study represents the first investigation of the demographic patterns of Cx. gelidus populations in Thailand using cytochrome c oxidase subunit I (COI) gene analysis and wing geometric morphometrics (GM). Mosquitoes were collected from 10 provinces across six regions of Thailand in 2022. Analysis of the COI sequences (n = 182) indicated high haplotype diversity (0.882) and low nucleotide diversity (0.006), with 72 haplotypes identified. The haplotype network demonstrated no profound splits among the geographic populations. Neutral tests, including Tajima's D and Fu's Fs, displayed negative values, with a significant result observed for Fu's Fs (-33.048, p < 0.05). The mismatch distribution analysis indicated that the population does not statistically deviate from a model of sudden population expansion (SSD = 0.010, p > 0.05; Rg = 0.022, p > 0.05). The estimations suggest that the Cx. gelidus population in Thailand began its expansion approximately between 459,243 and 707,011 years ago. The Mantel test showed no significant relationship between genetic and geographic distances (r = 0.048, p > 0.05). Significant phenotypic differences (based on wing shape) were observed among most populations. Additionally, in this study, we found no significant relationships between phenotypic and genetic distances (r = 0.250, p > 0.05). Understanding the genetic and morphological dynamics of Cx. gelidus is vital for developing targeted surveillance and vector control measures. This knowledge will also help to predict how future environmental changes might affect these populations, thereby informing long-term vector management strategies.
Topics: Animals; Thailand; Culex; Electron Transport Complex IV; Mosquito Vectors; Wings, Animal; DNA, Mitochondrial; Genetic Variation; Haplotypes; Female; Encephalitis, Japanese; Encephalitis Virus, Japanese; Male; Phylogeny
PubMed: 38821146
DOI: 10.1016/j.actatropica.2024.107276 -
Journal of Virology May 2024
PubMed: 38819169
DOI: 10.1128/jvi.00407-24 -
The Medical Journal of Australia Jun 2024
Topics: Humans; Australia; Encephalitis, Japanese; Encephalitis Virus, Japanese; Animals
PubMed: 38817085
DOI: 10.5694/mja2.52319 -
The Medical Journal of Australia Jun 2024To determine the proportion of people in New South Wales towns at high risk of Japanese encephalitis virus (JEV) infections during the 2022 outbreak; to identify risk...
OBJECTIVES
To determine the proportion of people in New South Wales towns at high risk of Japanese encephalitis virus (JEV) infections during the 2022 outbreak; to identify risk factors for JEV infection.
STUDY DESIGN
Cross-sectional serosurvey study of the seroprevalence of JEV-specific antibodies in NSW.
SETTING, PARTICIPANTS
Convenience sample of people (all ages) from five regional NSW towns deemed to be at high risk of JEV infections after first outbreak of Japanese encephalitis in southeastern Australia in early 2022 (Balranald, Corowa, Dubbo, Griffith, Temora), 21 June - 22 July 2022.
MAIN OUTCOME MEASURES
Proportion of people seropositive for JEV total antibody, assayed by defined epitope-blocking enzyme-linked immunosorbent assay; prevalence odds ratios for exposure risk factors and protective behaviours.
RESULTS
Eighty of 917 eligible participants (559 girls or women, 61%; 42 Aboriginal and Torres Strait Islander people, 4.6%; median age, 52 years [IQR, 37-62 years]) were seropositive for JEV-specific total antibody (8.7%); the median age of seropositive people was 61 years (IQR, 48-70 years). The seropositivity proportion was largest for people aged 65 years or more (30 of 192; weighted proportion, 13.7%) and larger for male than female participants (30 of 358, 10.6% v 50 of 559, 7.5%). Five of 42 samples from Aboriginal and Torres Strait Islander participants were seropositive (12%). We found mixed associations with a range of potential risk factors.
CONCLUSION
We found evidence for a substantial number of JEV infections in five regional NSW towns during a single arbovirus season in 2022. Public health responses, including effective surveillance, vaccination against JEV, and mosquito management, are critical for controlling outbreaks. Promoting behaviours that reduce exposure to mosquitoes is a core component of prevention, particularly when the vaccine supply is limited.
Topics: Adolescent; Adult; Aged; Child; Child, Preschool; Female; Humans; Infant; Male; Middle Aged; Young Adult; Antibodies, Viral; Cross-Sectional Studies; Disease Outbreaks; Encephalitis Virus, Japanese; Encephalitis, Japanese; New South Wales; Risk Factors; Seroepidemiologic Studies
PubMed: 38815982
DOI: 10.5694/mja2.52320