dengue: introduction flavivirus - · pdf file250.000 cases dhf mortality 2,5-5% a ... epidemic...
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FLAVIVIRUS
Master Virologa, Universidad Complutense de Madrid
Dr. Cristina Domingo CarrascoRobert Koch Institut, Berlin
Germany
DENGUE:INTRODUCTION
100.000.000 cases/year
250.000 cases DHF
Mortality 2,5-5%
AGLOBALPUBLICHEALTHISSUE
DENGUE:THEETHIOLOGICALAGENT
FlaviviridaeFamily:(YFV,WNV,SLEV,TBEV,JEV...)
Fourdifferentserotypes:
DENV1;DENV2;DENV3;DENV4
Serotypespecificlifelongimmunity
DENGUE:THEETHIOLOGICALAGENT
CAPSID
Eprotein
Mprotein
ENVE
LOP
RNAsinglestranded
STRUCTURALGENESNONSTRUCTURALGENES
DENGUEVIRUS:VECTORSANDHOSTS
Aedes aegypti
Aedes albopictus
DENGUEVIRUS:VECTORSANDHOSTS
?
ROUTESOFTRANSMISSION
MOSQUITOBITE(=percutaneousexposure)
NOSOCOMIALTRANSMISSIONNeedlestick(4cases)Nonpercutaneous(1case)Mosquitobitesinsidethehospital????
VERTICALTRANSMISSION
PATTERNSOFTRANSMISSION
EPIDEMICDENGUE Introductionofdenguevirusasanisolatedevent Involvingasinglestrain Largepopulationofsusceptiblehostsandmosquitoesarepresent Incidenceofinfectionamongindividuals2550% Dependingonherdimmunity,changesinweatherandmosquitocontrolefforts CertainareasofSouthAmerica,newintroducedareasofAsiaandAfrica Intervalsofyearsbetweenepidemics Bothadultsandchildrenareinfected Lowfrequencyofhemorrhagicfever
HYPERENDEMICDENGUE ContinouscirculationMultipledengueserotypesinthesamearea Yearroundpresenceofmosquitoesandlargepopulationbaseormovementsofpeople Seasonalvariation Incidenceofinfectionamongindividuals510%MorefrequentinchildrenMajorfactorcontributingtotheoccurrenceofhemorrhagicfever
DENGUEHAEMORRHAGICFEVER:ANEWFORMOFDISEASE?
NON ENDEMIC
HIPOENDEMIC
HIPERENDEMIC
DENGUEEMERGENCEANDREEMERGENCE
DENGUEEMERGENCEANDREEMERGENCE
43 DENGUE CASES
50,333 DENGUE
CASES
1980-1996 MEXICO/USA BORDER
Dengue:asocioeconomic disease?
Reiter P., et al. EID, 2003: vol 9 (1); 86-89
Dengue:asocioeconomic disease?
CLIMATECHANGEANDDENGUE:ACLOSEASSOCIATION?
Increasedintheviralreplicationrate
IncreaseintheAedespopulation
Diminishingitsdevelopingtime
Northernareasinvasion
Agriculturalpracticeschanges
Domesticwatersupplies
DENGUE:AREASOFTRANSMISSION
DENGUE:SOUTHEASTASIAANDWESTERNPACIFICREGIONS
Southeast AsiaHyperendemic transmission ofall four DENVsAll yearroundtransmissionPeaks Juneto NovemberNepalfirst casesin2004Indonesiamost casesSouthAsiaIndiaandSriLankaWesternPacific IslandsMalaysiaandPhilippinesFrenchPolynesia in2009AustraliaNonendemic but periodic introduction
DENGUE:REGIONOFTHEAMERICAS
Hyperendemic for the 4serotypes
NorthAmericaLatesummerfallMexico
CentralAmericaHondurasandCostaRica
CaribbeanOctoberDecember
SouthAmericaLowlevel year roundtransmissionBrazil peaks inFebruaryMarchBrazil,VenezuelaandColombia
DENGUE:AFRICANANDEASTERNMEDITERRANEANREGIONS
Scant dataOngoing denguetransmission mainlyobserved through travelersSeveral outbreak reported inWestAfricaSaudi Arabiareported outbreaks in2009
DENGUEINEUROPEANTRAVELERS
Source:TropNet Europ Sentinel Surveillance Report, May 2010
Popularityofthesecountriesastouristicdestination
Activityandpossiblevariationsinthevirulenceofdengueviruses
Vectoractivityinendemiccountries
Source: ECDC
DENGUEINEUROPE:RISKOFTRANSMISSION
Aedes albopictus establishment and spread inEurope
DENGUEINEUROPE:RISKOFTRANSMISSION
AugustSeptember
2010
September2010
Aedes albopictus establishment and spread inEurope
Straetemans M.Eurosurveillance 2008,vol 13(13)
aegypti