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Arbovirus

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Arbovirus

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  1. Arbovirus

  2. Arbovirus • viruses from various families which are transmitted via arthropods from one vertebrates to another. • Diseases caused by arboviruses • Encephalitis • febrile diseases • hemorrhagic fevers

  3. Flaviviridae Family Encephalitis B virus Epidemic encephalitis B Asia-subtropic or tropic regions Mosquito Dengue virus fever, hemorrhagic fever Worldwide – tropic regions Mosquito Forest encephalitis virus Forest encephalitis Worldwide Tick Bunyaviridae Family Xinjiang hemorrhagic fever virus Xinjiang hemorrhagic fever Xinjiang, China Tick

  4. Encephalitis B virus • Japanese encephalitis virus • Epidemic encephalitis B

  5. Biological Properties • 30-40nm • +ssRNA • envelope • icosahedral • only one serotype • E protein

  6. Epidemiology • Source • Mosquito and livestocks • Vector • mainly Culex tritaeniorhynchus • epidemic region • sub-tropic and tropic of Asia

  7. Encephalitis B virus

  8. pathogenicity • Pathogenesis • Two viremia • Clinical findings • subclinical infections • Acute encephalitis

  9. Prevent and Treatment • Prevention • Vector control • Avoid being bitten by mosquito • Eliminating all Culex breeding places • vaccination • man • Animal resovior • Treatment • no

  10. Dengue Virus • Flaviviridae • Flavivirus • four virus serotypes

  11. Pathogenicity • Source • human and primate • Vector • Mosquito • Occurrence • world wide---tropic or subtropic areas • Transmission • two viremia

  12. Aedes aegypti Mosquito

  13. Pathogenicity • Clinical Findings • dengue fever (DF) • dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) • Hypothesis on Pathogenesis of DHF • Antibody-dependent enhancement (ADE)

  14. 1 1 1 1 1 Homologous Antibodies Form Non-infectious Complexes Dengue 1 virus Neutralizing antibody to Dengue 1 virus Non-neutralizing antibody Complex formed by neutralizing antibody and virus

  15. 2 2 2 2 2 2 Heterologous Antibodies Form Infectious Complexes Dengue 2 virus Non-neutralizing antibody to Dengue 1 virus Complex formed by non-neutralizing antibody and virus

  16. 2 2 2 2 2 2 2 2 2 2 2 2 Heterologous Complexes Enter More Monocytes, Where Virus Replicates Dengue 2 virus Non-neutralizing antibody Complex formed by non-neutralizing antibody and Dengue 2 virus

  17. Dengue virus 皮下出血

  18. hantavirus