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VIRAL ZOONOSES1transmissionarthropod vectors(blood sucking)animal vectorsinhalation infected secretionscontact with infected secretionsdirect contact with infected animalsanimal bites2ARBOVIRUSESRODENT BORNE VIRUSESVECTOR UNKNOWN3VIGILANCE45ARBOVIRUSESENCEPHALITISFEBRILE DISEASESHEMORRHAGIC FEVERS6ARBOVIRUSESFAMILYENVELOPEyesyesnoSYMMETRYicosahedralhelicalicosahedralGENOMEssRNA(+ve)ssRNA(-ve)segmenteddsRNA,segmented78ARTHROPODHabitatDiurnal activityPreferred hostAnnual activityOverwintering abilityTransovarial transmissionVERTEBRATEMigratory activityPersistence of viremiaClinical consequencesReservoir?Dead end host?9ST LOUIS ENCEPHALITIS10PREVENTIONSURVEILLANCEVECTOR CONTROLREPELLENTSCLOTHINGTIMING OF ACTIVITY(OR CANCELLATION)VACCINE11PREVENTIONSURVEILLANCEVECTOR CONTROLREPELLENTSCLOTHINGTIMING OF ACTIVITY(OR CANCELLATION)VACCINE12SYLVATIC(JUNGLE)CYCLEarthropodarthropodvertebratemanvertebrate13URBAN CYCLEarthropodarthropodmanman14ARBOVIRUSESENCEPHALITISFEBRILE DISEASESHEMORRHAGIC FEVERS15ARBOVIRAL DISEASEMANY DIFFERENT ARBOVIRUSES CAUSE DISEASEOFTEN SUB-CLINICALINITIAL VIRAL REPLICATIONENDOTHELIAL CELLSMACROPHAGES/MONOCYTE LINEAGEINTERFERON(RNA VIRUSES)VIREMIA16RECOVERYINTERFERONCELL-MEDIATED IMMUNITYANTIBODY MAY PLAY A ROLE DURING VIREMIC PHASE17DIAGNOSISNew Yorker May 200018DIAGNOSISSPECIALIZED LABS19RESISTANCEIgG20ARBOVIRUSES ENCEPHALITIS DISTRIBUTION East US,CanadaWest US,Canada,Mexico,BrazilCentral and S America,Texas,FloridaNorth AmericaEast US,parts Europe,parts AfricaNorth America FAMILYTOGAVIRIDAEEastern equine encephalitisWestern equine encephalitisVenezuelan equine encephalitisFLAVIVIRIDAESt Louis encephalitisWest Nile virus encephalitisBUNYAVIRIDAECalifornia serogroup(La Crosse etc)21ARBOVIRUS ENCEPHALITISSPORADICLOW%INFECTIONS-CLINICAL CASESNOT ALL CASES-MAJOR DISEASECASE FATALITY RATIO(CFR)LOWPROBABLY UNDERDIAGNOSED22EASTERN EQUINE ENCEPALITISReservoir:birdsVector:mosquitoSentinelshorse,quail,turkeyChildren at higher riskCFR 35%5 cases/year av.CDCtogavirus23WESTERN EQUINE ENCEPALITISReservoir:birdsVector:mosquitoSentinelshorse,quail,turkeyChildren at higher riskCFR 3-5%No human cases recentlytogavirus24VENEZUELAN EQUINE ENCEPALITISReservoir:horseVector:mosquitoMild disease in mantogavirus25ST.LOUIS ENCEPHALITISCommonest mosquito borne disease in US Reservoir:birdscan have urban cycleVector:mosquito50yr old80 cases,8 deaths CFR 10%flavivirus27States in Enhanced WNV Surveillance and Control ProjectAlabamaConnecticutDelawareFloridaGeorgiaLouisianaMississippiMarylandMassachusettsNorth CarolinaNew JerseyNew YorkNew York CityPennsylvaniaRhode IslandSouth CarolinaTexasVirginiaWashington DCSpecial Congressional appropriation of$2.9 million,Fiscal Year 200028CALIFORNIA SEROGROUP ENCEPHALITIS(includes La Crosse virus)Recently commoner in eastern US Reservoir:small mammalsVector:mosquitosChildren at higher riskLow CFR70 cases/year av.bunyavirus29La Crosse life cycle30ARBOVIRUSES FEVER AND HEMORRHAGIC FEVERFAMILYFLAVIVIRIDAEDengueYellow feverREOVIRIDAEColorado tick feverDISTRIBUTION World wide,especially tropicsAfrica,S.and C.AmericaNorth America MAIN DISEASES fever,hemorrhagic feverhemorrhagic fever fever31COLORADO TICK FEVER Vector:tickMild disease in manFever,rash,arthralgiaRMSF important consideration in differential diagnosisProbably common,rarely reportedReovirus family32DENGUE FEVERjungle cycle(monkeys-mosquitos)urban cycle(man-mosquitos)rapidly increasing disease in tropicsevery year see in US due to importoccasional indigenous transmission50-100 million cases per year worldwideflavivirus33World Distribution of Dengue1999Areas infested with Areas infested with Aedes aegyptiAedes aegypti Areas with Areas with Aedes aegypti Aedes aegypti and recent epidemic dengue and recent epidemic dengue flavivirus34DENGUE FEVERfeverheadacheretro-orbital painmyalgia,arthralgiabone-ache breakbone feversometimes rashmay look like flu,measles,rubellaflavivirus35DENGUE HEMORRHAGIC FEVERhemorrhagesplasma leakagehemoconcentrationhypotensioncirculatory failureshockflavivirus36DENGUE HEMORRHAGIC FEVERchildren more severe diseasedo not give aspirin CFR depends on rapid responsecan be as low as 1%flavivirus37DENGUE HEMORRHAGIC FEVERimmunopathological4 serotypesmaternal antibody flavivirus38Reported Cases of DHF inthe Americas,1970-1998*Provisional data through 199839CDCYELLOW FEVERjungle and urban cycleshemorrhagesdegeneration liver,kidney,heartCFR 50%vaccineflavivirus40RODENT BORNE VIRUSESHEMORRHAGIC FEVERSHEMORRHAGIC FEVER WITH RENAL SYNDROMEPULMONARY SYNDROME41CDCrodent urinecontaminated materials(aerosols)respiratory tractROUTE OF INFECTION42RODENT BORNE FAMILYENVELOPEyesyesSYMMETRYhelicalhelicalGENOMEssRNA ambi-sensesegmentedssRNA(-ve)segmentedHantavirus genus43ARENAVIRUS-ASSOCIATED HEMORRHAGIC FEVERSLassa fever,Bolivian,Argentine hemorrhagic feverRecent cases in California of deaths thought to be associated with an arenavirus(Whitewater Arroyo Virus)dehydration,hemoconcentration,hemorrhage,shock CFR 5-35%CDC44Chronically infected Chronically infected rodentrodentVirus is present in Virus is present in aerosolized excreta,aerosolized excreta,particularly urineparticularly urineHorizontal transmission of Horizontal transmission of infection by intraspecific infection by intraspecific aggressive behavioraggressive behaviorVirus also present in throat swab Virus also present in throat swab and fecesand fecesSecondary aerosols,mucous membrane contact,Secondary aerosols,mucous membrane contact,and skin breaches are also a considerationand skin breaches are also a considerationTransmission of HantavirusesCDC45HANTAVIRUS-ASSOCIATED HEMORRHAGIC FEVERSKorean hemorrhagic fever with renal syndrome(CFR 7%)other HFRS viral diseases around the worldCDCHantavirus genus46HANTAVIRUS PULMONARY SYNDROMECFR 40-50%Hantavirus genus4748Radiographic Progression of Radiographic Progression of HPS in the LungHPS in the LungSource:Dr.L.Ketai via CDC49Hantavirus Pulmonary SyndromeLaboratory-confirmed DiagnosisHantavirus genus50VECTOR UNKNOWNHEMORRHAGIC FEVERS DUE TO EBOLA,MARBURG VIRUSES51VECTOR UNKNOWN FAMILYENVELOPEyes SYMMETRYhelical GENOME ssRNA(-ve)52Ebola and Marburg virusesRussell Regnery CDCFA Murphy UC Davis.vetnet.ucdavis.edu/fam_graphics/download.html53EBOLA AND MARBURG VIRUSEShemorrhagic feverscase fatality rate can be as high as 60-70%for certain strainsoccur in Africa,natural reservoir and vector unknownhigh viremia-stringent barrier nursing5455June 200056June 2000575859 September 20,199960July 25th,200061Aedes aegypti Breeding Sites626364American countries with laboratory-confirmed hemorrhagic fever(red shaded areas).65DENGUE HEMORRHAGIC FEVER66
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