资源描述
1 VIRAL ZOONOSES 2 transmission arthropod vectors (blood sucking) animal vectors inhalation infected secretions contact with infected secretions direct contact with infected animals animal bites 3 ARBOVIRUSES RODENT BORNE VIRUSES VECTOR UNKNOWN 4 VIGILANCE 5 6 ARBOVIRUSES ENCEPHALITIS FEBRILE DISEASES HEMORRHAGIC FEVERS 7 ARBOVIRUSES FAMILY ENVELOPE yes yes no SYMMETRY icosahedral helical icosahedral GENOME ssRNA (+ve) ssRNA (-ve) segmented dsRNA, segmented 8 9 ARTHROPOD Habitat Diurnal activity Preferred host Annual activity Overwintering ability Transovarial transmission VERTEBRATE Migratory activity Persistence of viremia Clinical consequences Reservoir ? Dead end host? 10 ST LOUIS ENCEPHALITIS 11 PREVENTION SURVEILLANCE VECTOR CONTROL REPELLENTS CLOTHING TIMING OF ACTIVITY (OR CANCELLATION) VACCINE 12 PREVENTION SURVEILLANCE VECTOR CONTROL REPELLENTS CLOTHING TIMING OF ACTIVITY (OR CANCELLATION) VACCINE 13 SYLVATIC (JUNGLE) CYCLE arthropod arthropod vertebrate man vertebrate 14 URBAN CYCLE arthropod arthropod man man 15 ARBOVIRUSES ENCEPHALITIS FEBRILE DISEASES HEMORRHAGIC FEVERS 16 ARBOVIRAL DISEASE MANY DIFFERENT ARBOVIRUSES CAUSE DISEASE OFTEN SUB-CLINICAL INITIAL VIRAL REPLICATION ENDOTHELIAL CELLS MACROPHAGES/MONOCYTE LINEAGE INTERFERON (RNA VIRUSES) VIREMIA 17 RECOVERY INTERFERON CELL-MEDIATED IMMUNITY ANTIBODY MAY PLAY A ROLE DURING VIREMIC PHASE 18 DIAGNOSIS New Yorker May 2000 19 DIAGNOSIS SPECIALIZED LABS 20 RESISTANCE IgG 21 ARBOVIRUSES ENCEPHALITIS DISTRIBUTION East US, Canada West US, Canada, Mexico, Brazil Central and S America, Texas, Florida North America East US, parts Europe, parts Africa North America FAMILY TOGAVIRIDAE Eastern equine encephalitis Western equine encephalitis Venezuelan equine encephalitis FLAVIVIRIDAE St Louis encephalitis West Nile virus encephalitis BUNYAVIRIDAE California serogroup (La Crosse etc) 22 ARBOVIRUS ENCEPHALITIS SPORADIC LOW % INFECTIONS - CLINICAL CASES NOT ALL CASES - MAJOR DISEASE CASE FATALITY RATIO (CFR) LOW PROBABLY UNDERDIAGNOSED 23 EASTERN EQUINE ENCEPALITIS Reservoir: birds Vector: mosquito Sentinels horse,quail, turkey Children at higher risk CFR 35% 5 cases/year av. CDC togavirus 24 WESTERN EQUINE ENCEPALITIS Reservoir: birds Vector: mosquito Sentinels horse,quail, turkey Children at higher risk CFR 3-5% No human cases recently togavirus 25 VENEZUELAN EQUINE ENCEPALITIS Reservoir: horse Vector: mosquito Mild disease in man togavirus 26 ST. LOUIS ENCEPHALITIS Commonest mosquito borne disease in US Reservoir: birds can have urban cycle Vector: mosquito 50yr old 80 cases, 8 deaths CFR 10% flavivirus 28 States in Enhanced WNV Surveillance and Control Project Alabama Connecticut Delaware Florida Georgia Louisiana Mississippi Maryland Massachusetts North Carolina New Jersey New York New York City Pennsylvania Rhode Island South Carolina Texas Virginia Washington DC Special Congressional appropriation of $2.9 million, Fiscal Year 2000 29 CALIFORNIA SEROGROUP ENCEPHALITIS (includes La Crosse virus) Recently commoner in eastern US Reservoir: small mammals Vector: mosquitos Children at higher risk Low CFR 70 cases/year av. bunyavirus 30 La Crosse life cycle 31 ARBOVIRUSES FEVER AND HEMORRHAGIC FEVER FAMILY FLAVIVIRIDAE Dengue Yellow fever REOVIRIDAE Colorado tick fever DISTRIBUTION World wide, especially tropics Africa, S. and C. America North America MAIN DISEASES fever, hemorrhagic fever hemorrhagic fever fever 32 COLORADO TICK FEVER Vector: tick Mild disease in man Fever, rash, arthralgia RMSF important consideration in differential diagnosis Probably common, rarely reported Reovirus family 33 DENGUE FEVER jungle cycle (monkeys-mosquitos) urban cycle (man-mosquitos) rapidly increasing disease in tropics every year see in US due to import occasional indigenous transmission 50-100 million cases per year worldwide flavivirus 34 World Distribution of Dengue 1999 Areas infested with Aedes aegypti Areas with Aedes aegypti and recent epidemic dengue flavivirus 35 DENGUE FEVER fever headache retro-orbital pain myalgia, arthralgia bone-ache breakbone fever sometimes rash may look like flu, measles, rubella flavivirus 36 DENGUE HEMORRHAGIC FEVER hemorrhages plasma leakage hemoconcentration hypotension circulatory failure shock flavivirus 37 DENGUE HEMORRHAGIC FEVER children more severe disease do not give aspirin CFR depends on rapid response can be as low as 1% flavivirus 38 DENGUE HEMORRHAGIC FEVER immunopathological 4 serotypes maternal antibody flavivirus 39 Reported Cases of DHF in the Americas, 1970 - 1998 0100002000030000400005000060000Reported Cases1970s1980s1990s* Provisional data through 1998 40 CDC YELLOW FEVER jungle and urban cycles hemorrhages degeneration liver, kidney, heart CFR 50% vaccine flavivirus 41 RODENT BORNE VIRUSES HEMORRHAGIC FEVERS HEMORRHAGIC FEVER WITH RENAL SYNDROME PULMONARY SYNDROME 42 CDC rodent urine contaminated materials (aerosols) respiratory tract ROUTE OF INFECTION 43 RODENT BORNE FAMILY ENVELOPE yes yes SYMMETRY helical helical GENOME ssRNA ambi-sense segmented ssRNA (-ve) segmented Hantavirus genus 44 ARENAVIRUS-ASSOCIATED HEMORRHAGIC FEVERS Lassa fever, Bolivian, Argentine hemorrhagic fever Recent cases in California of deaths thought to be associated with an arenavirus (Whitewater Arroyo Virus) dehydration, hemoconcentration, hemorrhage, shock CFR 5-35% CDC 45 Chronically infected rodent Virus is present in aerosolized excreta, particularly urine Horizontal transmission of infection by intraspecific aggressive behavior Virus also present in throat swab and feces Secondary aerosols, mucous membrane contact, and skin breaches are also a consideration Transmission of Hantaviruses CDC 46 HANTAVIRUS-ASSOCIATED HEMORRHAGIC FEVERS Korean hemorrhagic fever with renal syndrome (CFR 7%) other HFRS viral diseases around the world CDC Hantavirus genus 47 HANTAVIRUS PULMONARY SYNDROME CFR 40-50% Hantavirus genus 48 49 Radiographic Progression of HPS in the Lung Source: Dr. L. Ketai via CDC 50 Hantavirus Pulmonary Syndrome Laboratory-confirmed Diagnosis Hantavirus genus 51 VECTOR UNKNOWN HEMORRHAGIC FEVERS DUE TO EBOLA, MARBURG VIRUSES 52 VECTOR UNKNOWN FAMILY ENVELOPE yes SYMMETRY helical GENOME ssRNA (-ve) 53 Ebola and Marburg viruses Russell Regnery CDC FA Murphy UC Davis http:/www.vetnet.ucdavis.edu/fam_graphics/download.html 54 EBOLA AND MARBURG VIRUSES hemorrhagic fevers case fatality rate can be as high as 60-70% for certain strains occur in Africa, natural reservoir and vector unknown high viremia - stringent barrier nursing 55 56 June 2000 57 June 2000 58 59 60 September 20, 1999 61 July 25th, 2000 62 Aedes aegypti Breeding Sites 63 64 65 American countries with laboratory-confirmed hemorrhagic fever (red shaded areas). 66 DENGUE HEMORRHAGIC FEVER
展开阅读全文