Dengue:Epidemiology,clinicalmanagementandcontrol

PORNTHIPCHAICHOMPOO

pornthip.chh@mahidol.ac.th

SCBM 346 Tropical infectious diseases and controls

DEPARTMENT OF PATHOBIOLOGY, FACULTY OF SCIENCE, MAHIDOL UNIVERSITY

References

Learningobjectives

Atthecompletionofthisunitthestudentwillbeableto:

• Explainbiologyandinfectioncycle ofdenguevirus• Discusstheepidemiologyofdengueinfectionandpublichealthproblem

• Demonstrateclinicalmanagement,preventionandcontrol ofdengueinfection

• (+)ssRNA virus• Family Flaviviridae• Genera Flavivirus• SpeciesDenguevirus

(DEN-1,DEN-2,DEN-3&DEN-4)• ArbovirusArthropod,Mosquito,born

(Aedes aegypti)• Pathogenic diseasesDenguefever/DHF/DSS

BiologyofDenguevirus

DENGUEVIRUS

Screaton G,etal.NatRevImmunol.2015Dec;15(12):745-59.

Infectiouscycle:Immature

Mature

host-encoded furin protease

Infected person

Healthy person

Infected mosquito

Incubation Period: 3 to 14 daysMost commonly 4 to 7 days

Denguetransmissioncycle

Otherroutesoftransmission

• Transplantation:Blood/Bonemarrow,organ(renaltransplantation)

• Verticaltransmission:DENVcanbetransmittedfromthemothertothefetusinuteroortotheneonateatparturition.

Aedes aegypti

Vector

InfectedFemaleMosquito

rarelyAedes albapticus

PathogenesisofDengueinfection

Navarro-Sa´nchez E, et al.Archi Med Res.2005; 36:425–35.9

Webster DP, et al. Lancet.2009;9(11):678-87.

PathogenesisofDengueinfection

10

Dengueasanemergingdisease

• DENwasaminor,geographicallyrestricteddiseaseuntilmid-20thcentury

• WorldWarII/globalcargotransportofAedesmosquitoeslikelyresponsiblefordissemination

• DEN/DHFpresentintheWHOregionsoftheAmericas,South-EastAsia,EasternMediterraneanandWesternPacific;AfricareportsDENbutonlysporadicDHF

• DHFfirstdocumentedin1950sinthePhilippinesandThailand

DengueasanemergingdiseaseAverageannualnumberofdenguefever(DF)anddenguehemorrhagicfever(DHF)casesreportedtoWHO,andofcountriesreportingdengue,1955–2007

DengueintheSouth-EastAsiaRegion

• Since2000,epidemicdenguehasspreadtonewareasandhasincreasedinthealreadyaffectedareasoftheregion.

• EpidemicdengueisamajorpublichealthprobleminIndonesia,Myanmar,SriLanka,ThailandandTimor-Leste.

• InThailand,dengueisreportedfromall4regions:Northern,Central,North-EasternandSouthern.

• InJune2007,outbreakswerereportedfromTratprovince,Bangkok,Chiangrai,Phetchabun,Phitsanulok,Khamkaeng Phet,NakhonSawan andPhit Chit.

• Atotalof58,836caseswerereportedfromJanuarytoNovember2007.Thecase-fatalityrateinThailandisbelow0.2%.

©WorldHealthOrganization2009

DengueintheWesternPacificRegion

• DengueisamajorpublichealthproblemintheWesternPacificRegion• Allfourserotypes(DENV-1,-2,-3,-4)arepresentintheRegion

• Occursthroughouttheyearbutratesincrease1-2monthsafterthestartoftherainyseasoninJune

• Lackofreportingremainsanimportantchallengeinpreventionandcontrol

DengueintheEasternMediterraneanRegion

©WorldHealthOrganization2009

DengueintheAmericas

©WorldHealthOrganization2009

• Thebiggestoutbreakoccurredin2002 withmorethan1millionreportedcases.

• 2001-2007,>30countriesoftheAmericasnotifiedatotalof4,332,731casesofdengue.

• ThenumberofcasesofDHF inthesameperiodwas106,037.

• Thetotalnumberofdenguedeathsfrom2001to2007was1299,withaDHFcasefatalityrateof1.2%.

• Thefourserotypesofthedenguevirus(DEN-1,DEN-2,DEN-3andDEN-4)circulateintheregion.

DengueintheAfricanRegion

©WorldHealthOrganization2009

• EasternAfrica,theavailableevidencesofarindicatesthatDEN-1,-2and-3appeartobecommoncausesofacutefever.

• WesternAfricainthe1960s,DEN-1,-2and-3wereisolatedforthefirsttimefromsamplestakenfromhumansinNigeria.

• DenguemaynotappeartobeamajorpublichealthprobleminAfrica comparedtothewidespreadincidenceofmalariaandHIV/AIDS.

• Severalcombiningfactorsproduceepidemiologicalconditionsintropicalandsubtropicaldevelopingcountriesthatfavouring viraltransmissionbyAedes aegypti:

Dengueasanemergingdisease

• Rapidpopulationgrowth• Rural–Urbanmigration• Inadequatebasicurban

infrastructure• Increaseinvolumeofsolid

wastewhichprovidelarvalhabitatsinurbanareas.

• Dengueinflictsserioushealthandsocioeconomicburden• DALY’slosttodengue=528in20011

• TheoverallcostofadenguecaseisUS$8282

• Estimatesignore:• underreportingofcases• substantialcostsassociatedwithdenguesurveillanceandvectorcontrolprogrammes.

Diseaseburden

1 Cattand et al. Tropical Diseases Lacking Adequate Control Measures: Dengue, Leishmaniasis, and AfricanTrypanosomiasis. Disease Control Priorities in Developing Countries, World Bank, 2006.2 Suaya et al. Costs of dengue cases in 8 countries in the Americas and Asia: A prospective study. Am J Trop MedHyg, 2009, 80:846-855.

Patientassessment forDengueinfection

Step1:Historytaking

Step2:Clinicalexamination

Step3:Investigations

Step4:Diagnosis,phaseofdiseaseandseverity

Step1:Historytaking

Step1:Historytaking

DENGUECASEINVESTIGATIONREPORT

Step2:Clinicalexamination

DENGUECASEINVESTIGATIONREPORT

DENGUECASEINVESTIGATIONREPORT

HemodynamicAssessment– STABLECIRCULATION

HemodynamicAssessmentinCOMPENSATEDSHOCK

HemodynamicAssessmentinCOMPENSATEDSHOCK

KEY:Clinicalexaminationofdenguepatients

Step3:Investigation

Step3:Investigation

Step3:Investigation

Step4:Diagnosis,phaseofdiseaseandseverity

1.Doesthepatienthavedengueorotherillnesses?2.Whichphaseofdengue(febrile/critical/recovery)?3.Whatisthehydrationstate?4.Aredenguewarningsignspresent?5.Whatisthehemodynamicstate?6.Whatisthebestmedicalplanforthepatient?

Primaryprevention

• Avoidbeingbitten(justafterdawnuntiljustaftersunset)

• BugGuardagents• Oiloflemoneucalyptus:Repel• Wearlong-sleevedshirtandlongpantswhenoutdoors• Usescreensinhouse

• Killadultmosquitoesandlarvainyourhome

Prevention&Controldengueinfection

Vector control

1. Environmentalmanagement2. Chemicalcontrol:larvicides3. Chemicalcontrol:adulticides4. Safeuseofinsecticides5. Monitoringofinsecticidesusceptibility6. Individualandhouseholdprotection7. Biologicalcontrol8. Towardsimprovedtoolsforvectorcontrol

Delivery of vector control interventions

Prevention&Controldengueinfection

1. Linkstoepidemiologicalservices2. Advocacy,socialmobilizationandlegislation3. Socialmobilizationandcommunication4. Collaborationwithinthehealthsectorandwithothersectors5. Integratedapproachestocontrol6. Strengtheningcapacity7. Operationalresearch8. Monitoringandevaluation

Denguepreventionandcontrol:examplesofgoodandbadpractice

Assignment• Oneassignmentpergroup• Brainstorm30min• Presentation&Discussion20min/group

Assignment1

DevelopcontrolstrategiestoaddressdengueinfectioninJapan

Dengue Virus Type 2 in Travelers Returning to Japan from Sri Lanka, 2017

Emerging Infectious Diseases2017;23(11):1931-3.

Assignment2

• Developcontrolstrategiesto effectiveeliminatemosquitoes

Would it be wrong to eradicate mosquitoes?

Assignment3

• Developcontrolstrategiestomanagedenguecaseclassificationandlevelsofseverityinprimarycare(outsideBangkok).