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Virus Research Jul 2023Japanese encephalitis virus (JEV) is a mosquito-borne zoonotic virus that can cause severe viral encephalitis. Initial interactions between JEV and host cells are... (Review)
Review
Japanese encephalitis virus (JEV) is a mosquito-borne zoonotic virus that can cause severe viral encephalitis. Initial interactions between JEV and host cells are required for productive viral infection and initiation of the viral life cycle. The elucidation of these interactions is critical, not only to understand the pathogenesis of JEV infection, but also to design efficient antiviral strategies. In this review, we outline the known viral and cellular components involved in JEV entry into host cells, with a particular focus on the initial virus-host cell interaction on the cell surface and the downstream early events such as endocytosis, membrane fusion, and viral genome release.
Topics: Animals; Humans; Encephalitis Virus, Japanese; Host Microbial Interactions; Virus Internalization; Encephalitis, Japanese; Endocytosis; Encephalitis Viruses, Japanese; Virus Replication
PubMed: 37086856
DOI: 10.1016/j.virusres.2023.199120 -
MBio Aug 2023Survivors of Powassan encephalitis often have persistent neurological disease. A new mouse model replicates some elements of the human disease and demonstrates the...
Survivors of Powassan encephalitis often have persistent neurological disease. A new mouse model replicates some elements of the human disease and demonstrates the presence of viral RNA in the brain as well as myelitis more than 2 mo after the acute infection. The related tick-borne encephalitis and West Nile Neuroinvasive Disease (WNND) also have common neurological sequelae, and models for these better-studied diseases provide evidence for prolonged virus, RNA, and inflammation in some cases, in addition to damage from the acute encephalitic disease. A better understanding of the biological basis for persistent signs and symptoms after Powassan encephalitis, currently a rare disease, could benefit from further studies of the more prevalent flaviviral encephalitides.
Topics: Animals; Mice; Humans; Encephalitis Viruses, Tick-Borne; Encephalitis, Tick-Borne; Mice, Inbred C57BL; Flavivirus Infections; Nervous System Diseases
PubMed: 37338444
DOI: 10.1128/mbio.00712-23 -
The Journal of Experimental Medicine Sep 2023Mosquito-borne West Nile virus (WNV) infection is benign in most individuals but can cause encephalitis in <1% of infected individuals. We show that ∼35% of patients...
Mosquito-borne West Nile virus (WNV) infection is benign in most individuals but can cause encephalitis in <1% of infected individuals. We show that ∼35% of patients hospitalized for WNV disease (WNVD) in six independent cohorts from the EU and USA carry auto-Abs neutralizing IFN-α and/or -ω. The prevalence of these antibodies is highest in patients with encephalitis (∼40%), and that in individuals with silent WNV infection is as low as that in the general population. The odds ratios for WNVD in individuals with these auto-Abs relative to those without them in the general population range from 19.0 (95% CI 15.0-24.0, P value <10-15) for auto-Abs neutralizing only 100 pg/ml IFN-α and/or IFN-ω to 127.4 (CI 87.1-186.4, P value <10-15) for auto-Abs neutralizing both IFN-α and IFN-ω at a concentration of 10 ng/ml. These antibodies block the protective effect of IFN-α in Vero cells infected with WNV in vitro. Auto-Abs neutralizing IFN-α and/or IFN-ω underlie ∼40% of cases of WNV encephalitis.
Topics: Animals; Chlorocebus aethiops; Humans; West Nile Fever; West Nile virus; Vero Cells; Autoantibodies; Antibodies, Viral; Interferon Type I; Interferon-alpha
PubMed: 37347462
DOI: 10.1084/jem.20230661 -
Journal of Clinical Medicine Oct 2023The tick-borne encephalitis virus (TBEV) is the arboviral etiological agent of tick-borne encephalitis (TBE), considered to be one of the most important tick-borne viral... (Review)
Review
The tick-borne encephalitis virus (TBEV) is the arboviral etiological agent of tick-borne encephalitis (TBE), considered to be one of the most important tick-borne viral diseases in Europe and Asia. In recent years, an increase in the incidence of TBE as well as an increasing geographical range of the disease have been noted. Despite the COVID-19 pandemic and the imposition of restrictions that it necessitated, the incidence of TBE is rising in more than half of the European countries analyzed in recent studies. The virus is transmitted between ticks, animals, and humans. It seems that ticks and small mammals play a role in maintaining TBEV in nature. The disease can also affect dogs, horses, cattle, and small ruminants. Humans are incidental hosts, infected through the bite of an infected tick or by the alimentary route, through the consumption of unpasteurized milk or milk products from TBEV-infected animals. TBEV infections in humans may be asymptomatic, but the symptoms can range from mild flu-like to severe neurological. In Europe, cases of TBE are reported every year. While there is currently no effective treatment for TBE, immunization and protection against tick bites are critical in preventing this disease.
PubMed: 37892741
DOI: 10.3390/jcm12206603 -
Ugeskrift For Laeger Oct 2023Tick-borne encephalitis (TBE) is a viral tick-borne infection occurring in many parts of Europe and Asia as described in this review. Increasing TBE case numbers have... (Review)
Review
Tick-borne encephalitis (TBE) is a viral tick-borne infection occurring in many parts of Europe and Asia as described in this review. Increasing TBE case numbers have been reported over recent decades. In Denmark the infection is rare (1-14 annual cases). The rise in TBE in Denmark is mainly driven by microfoci outside of Bornholm, primarily North Zealand. Clinical illness has a bi-phasic presentation: "summer-flu" which may be followed by a neuroinfection. No specific treatment exists, and mortality is less-than 1%. A considerable percentage of patients may experience neurological sequelae. TBE is preventable through vaccination.
Topics: Humans; Encephalitis, Tick-Borne; Encephalitis Viruses, Tick-Borne; Europe; Seasons; Vaccination
PubMed: 37921107
DOI: No ID Found -
Ugeskrift For Laeger Oct 2023Tick-borne encephalitis is a rare infection in Denmark. The infection has been endemic to the island of Bornholm for many years. During the past 10 years, transmission...
Tick-borne encephalitis is a rare infection in Denmark. The infection has been endemic to the island of Bornholm for many years. During the past 10 years, transmission has occurred in other parts of Denmark, particularly North Zealand. This case report describes a typical tick-borne encephalitis case diagnosed in the first viraemic phase of the disease course. Clinical presentation and diagnostic criteria are described.
Topics: Humans; Encephalitis Viruses, Tick-Borne; Encephalitis, Tick-Borne; Male; Middle Aged
PubMed: 37921110
DOI: No ID Found -
Frontiers in Cellular and Infection... 2023The Japanese encephalitis virus (JEV) is classified into five distinct genotypes, with genotypes 1 and 3 historically showing higher activity. These genotypes are the... (Review)
Review
The Japanese encephalitis virus (JEV) is classified into five distinct genotypes, with genotypes 1 and 3 historically showing higher activity. These genotypes are the primary agents of viral encephalitis in the Asian continent. Genotypes 4 and 5 have remained silent in low-latitude tropical regions since their discovery. From 2009, the hidden genotype 5 suddenly emerged simultaneously in mosquitoes from the Tibetan region of China and those from South Korea in East Asia. The detection of genotype 5 of JEV in these mosquitoes was associated with cases of viral encephalitis in the local population. Similarly, in 2022, the long-silent genotype 4 of JEV emerged in Australia, resulting in a local outbreak of viral encephalitis that primarily affected adults and caused fatalities. The emergence and outbreaks of genotypes 4 and 5 of JEV present new challenges for the prevention and control of Japanese encephalitis (JE). This study not only analyzes the recent emergence of these new genotypes but also discusses their implications in the development of JE vaccines and laboratory tests for newly emerging JEV infections.
Topics: Adult; Animals; Humans; Encephalitis Virus, Japanese; Encephalitis, Japanese; Culicidae; Genotype; Disease Outbreaks
PubMed: 38076463
DOI: 10.3389/fcimb.2023.1292693