复旦大学：《医学微生物学 Medical Microbiology（MBBS）》课程讲义_理论课_Lecture22-Arboviruses & rodent-borne viurs

Arthropod-borne viruses(Arboviruses) rodent-borne viruses (虫媒病毒&病毒性出血热) Shibo Jiang(姜世勃) MOH&MOE Key Lab of Medical Molecular Virology Shanghai Medical College, Fudan University 复旦大学上海医学院分子病毒学教育部/卫生部重点实

Arthropod-borne viruses (Arboviruses) & rodent-borne viruses (虫媒病毒 & 病毒性出血热) Shibo Jiang (姜世勃) MOH&MOE Key Lab of Medical Molecular Virology Shanghai Medical College, Fudan University 复旦大学上海医学院分子病毒学教育部/卫生部重点实验室

Comparison of arthropod- and rodent-borne viruses Viruses arthropod-borne viruses rodent-borne viruses Reservoir hosts arthropods(e.g, mosquitoes, and rodents (e.g, mice, rats, ticks) squirrels, and hamsters) bloodsucking arthropods from one contact with body fluids or Transmitted by vertebrate host to another excretions of rodents ellow fever, dengue, Japanese b hantavirus infections encephalitis, St Louis encephalitis, Lassa fever, South Major diseases western equine encephalitis, eastern American hemorrhagic equine encephalitis, Russian spring- fevers, and African summer encephalitis, West Nile hemorrhagic fevers fever, and sandfly fever (Marburg and Ebola

Viruses arthropod-borne viruses rodent-borne viruses Reservoir hosts arthropods (e.g., mosquitoes, and ticks) rodents (e.g., mice, rats, squirrels, and hamsters) Transmitted by bloodsucking arthropods from one vertebrate host to another contact with body fluids or excretions of rodents Major diseases yellow fever, dengue, Japanese B encephalitis, St. Louis encephalitis, western equine encephalitis, eastern equine encephalitis, Russian spring￾summer encephalitis, West Nile fever, and sandfly fever hantavirus infections, Lassa fever, South American hemorrhagic fevers, and African hemorrhagic fevers (Marburg and Ebola) Comparison of arthropod- and rodent-borne viruses

Part Arthropod-borne viruses (Arboviruses Overview General information of arbovirus Main properties of togaviruses (alphavirus) Chikungunya caused by alphavirus Main properties of flaviviruses Dengue fever caused by flavivirus Japanese B Encephalitis caused by flavivirus

Part I Arthropod-borne viruses (Arboviruses ) Overview  General information of arbovirus  Main properties of togaviruses (alphavirus)  Chikungunya caused by alphavirus  Main properties of flaviviruses  Dengue fever caused by flavivirus  Japanese B Encephalitis caused by flavivirus

Arboviruses Arboviruses spread by arthropod vectors such as mosquitoes, ticks, and flies It has four families: togaviruses, flaviviruses bunyaviruses and reoviruses The major arbovirus disease worldwide are yellow fever, dengue, Japanese B encephalitis, St Louis encephalitis, Russian spring-summer encephalitis Most illnesses caused by these viruses are mild fevers; some may cause severe encephalitis, and life-threatening hemorrhagic fever

 Arboviruses spread by arthropod vectors, such as mosquitoes, ticks, and flies  It has four families: togaviruses, flaviviruses, bunyaviruses and reoviruses  The major arbovirus disease worldwide are yellow fever, dengue, Japanese B encephalitis, St. Louis encephalitis, Russian spring-summer encephalitis.  Most illnesses caused by these viruses are mild fevers; some may cause severe encephalitis, and life-threatening hemorrhagic fever. Arboviruses

The influence of the vectors Vectors and viruses tend to be clustered in the tropics and subtropics; many temperate zones have periodic epidemics Arbovirus life cycles are closely tied to the ecology of the vectors Infections show a peak incidence when the arthropod is actively feeding and reproducing(e. g Dengue fever's peak in Taiwan is Oct or Nov) Humans can serve as dead-end. accidental hosts or a maintenance reservoir Controlling the vector controls the disease

The influence of the Vectors  Vectors and viruses tend to be clustered in the tropics and subtropics; many temperate zones have periodic epidemics.  Arbovirus life cycles are closely tied to the ecology of the vectors.  Infections show a peak incidence when the arthropod is actively feeding and reproducing (e.g., Dengue fever’s peak in Taiwan is Oct or Nov).  Humans can serve as dead-end, accidental hosts or a maintenance reservoir.  Controlling the vector controls the disease

Common arboviruses Species(of high economic/epidemiologic Family Genera importance) Vectors Diseases caused Eastern equine enceph virus, O'nyong'nyong virus, Ross River virus, Togaviridae Alphavirus Semliki Forest virus, Venezuelan equine encephalitis virus, Western equine encephalitis virus mosquito viral encephalitis, arthritis Flaviviridae Flavivirus St Louis encephalitis virus. west nile virus mosquito viral encephalitis Flaviviridae Flavivirus Murray valley encephalitis virus, viral encephalitis, viral Yellow fever virus mosquito hemorrhagic fever Flaviviridae Flavivirus Louping ill virus, Powassan virus, Tick-borne encephalitis virus tick(Ixodes spp viral encephalitis Bunyaviridae Phlebovirus Rift Valley fever virus mosquito(Aedes viral encephalitis, viral spp, Culex spp. hemorrhagic fever Bunyaviridae Phlebovirus Pappataci fever, Toscana virus Phlebotomus spp fever Orthobunya California encephalitis virus, La Crosse Bunyaviridae vi encephalitis mosquito viral encephalitis Bunyaviridae Nairovirus Crimean-Congo hemorrhagic fever virus c viral hemorrhagic fever Anopheles A, Anopheles B, Bakau, Crimean-Congo hemorrhagic fever, Kaisodi, Mapputta, Nairobi Bunyaviridae Uukuvirus sheep disease, Phlebotomus fever, Turlock; viral encephalitis, viral un-assigned viruses hemorrhagic fever Reoviridae Coltivirus Colorado tick fever virus viral hemorrhagic fever African horse sickness virus, Bluetongue diseaseCeratopogonidae Reoviridae Orbivirus virus, Epizootic hemorrhagic disease virus (Culicoides spp. viral encephalitis

Common Arboviruses Family Genera Species (of high economic/epidemiologic importance) Vectors Diseases caused Togaviridae Alphavirus Chikungunya virus, Eastern equine encephalitis virus, O'nyong'nyong virus, Ross River virus, Semliki Forest virus, Venezuelan equine encephalitis virus, Western equine encephalitis virus mosquito viral encephalitis, arthritis Flaviviridae Flavivirus Japanese encephalitis virus, St. Louis encephalitis virus, West Nile virus mosquito viral encephalitis Flaviviridae Flavivirus Dengue virus, Murray Valley encephalitis virus, Yellow fever virus mosquito viral encephalitis, viral hemorrhagic fever Flaviviridae Flavivirus Louping ill virus, Powassan virus, Tick-borne encephalitis virus tick (Ixodes spp.) viral encephalitis Bunyaviridae Phlebovirus Rift Valley fever virus mosquito (Aedes spp., Culex spp.) viral encephalitis, viral hemorrhagic fever Bunyaviridae Phlebovirus Pappataci fever, Toscana virus Phlebotomus spp. fever Bunyaviridae Orthobunya virus California encephalitis virus, La Crosse encephalitis mosquito viral encephalitis Bunyaviridae Nairovirus Crimean–Congo hemorrhagic fever virus tick viral hemorrhagic fever Bunyaviridae Uukuvirus Anopheles A, Anopheles B, Bakau, Crimean-Congo hemorrhagic fever, Kaisodi, Mapputta, Nairobi sheep disease, Phlebotomus fever, Turlock; 8 un-assigned viruses tick viral encephalitis, viral hemorrhagic fever Reoviridae Coltivirus Colorado tick fever virus tick viral hemorrhagic fever Reoviridae Orbivirus African horse sickness virus, Bluetongue disease virus, Epizootic hemorrhagic disease virus Ceratopogonidae (Culicoides spp.) viral encephalitis

Family: Togaviridae Genus: Alphavirus

Family: Togaviridae Genus: Alphavirus

Properties of Alphavirus Genus Alphavirus Chikungunya eastern, Spherical, 70 nm in western, and Venezuelan diameter, nucleocapsid has equine encephalitis viruses, 42 capsomeres Genome Mayaro, O' Nyong-nyong, positive-sense, single- Ross River semliki forest, stranded RNA, 11-12 kb in and sindbis viruses size Envelope. three or Arthropod-borne four major structural (mosquitoes) polypeptides, two glycosylated Replication: cytoplasm. Assembly budding through host cell membranes. All viruses serologically related

Properties of Alphavirus

Chikungunya The name is derived from the Makonde word meaning " bends up"in reference to the stooped posture developed as a result of the arthritic symptoms of the disease Chikungunya is a relatively rare form of viral fever(non-fatal viral illness) caused by alphavirus through mosquitoes Aedes aegypti mosquito

Chikungunya  The name is derived from the Makonde word meaning "bends up" in reference to the stooped posture developed as a result of the arthritic symptoms of the disease.  Chikungunya is a relatively rare form of viral fever (non-fatal viral illness) caused by alphavirus through mosquitoes. Aedes aegypti mosquito

Epidemiology of chikungunya Chikungunya was first described in Tanzania, Africa in1952 An outbreak of chikungunya was discovered in 1999 in Port Klang in Malaysia, affecting 27 people a big outbreak was recorded in 2005 on the french island of reunion in the Indian ocean More than 250,000(1/3 residents were infected by the virus, resulting in about 220 deaths(0.1%

Epidemiology of Chikungunya  Chikungunya was first described in Tanzania, Africa in 1952.  An outbreak of chikungunya was discovered in 1999 in Port Klang in Malaysia, affecting 27 people.  A big outbreak was recorded in 2005 on the French island of Réunion in the Indian Ocean. More than 250,000 (1/3) residents were infected by the virus, resulting in about 220 deaths (～0.1%)