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