5 dengue sage apr2013 global strategy

8/20/2019 5 Dengue SAGE Apr2013 Global Strategy

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GLOBAL STRATEGY

FOR DENGUE PREVENTION AND CONTROL


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GLOBAL STRATEGY

FOR DENGUE PREVENTION AND CONTROL


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WHO Library Cataloguing-in-Publication Data

Global strategy for dengue prevention and control 2012-2020.

1.Dengue – prevention and control. 2.Dengue – epidemiology. 3.Endemic diseases – prevention and control. 4.Disease outbreaks– prevention and control. 5.Mosquito control. 6.Health planning. I.World Health Organization.

ISBN 978 92 4 150403 4 (NLM classification: WC 528)

© World Health Organization 2012

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interpretation and use of the material lies with the reader. In no event shall the World Health Organization be liable for damages arisingfrom its use.

Printed in France

Design & layout: Patrick Tissot WHO/HTM/NTD


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CONTENTS

FOREWORD ............................................................................................................................. iv

EXECUTIVE SUMMARY ................................................................................................................ v

1. DENGUE: A GLOBAL THREAT – GLOBAL ANSWERS ..................................................................1

1.1 Burden of the disease ....................................................................................................1 1.2 Reversing the trend ........................................................................................................3 1.3 Opportunities for investment ...........................................................................................4

2. THE GLOBAL STRATEGY FOR DENGUE PREVENTION AND CONTROL .......................................6

2.1 Goal and objectives ......................................................................................................6 2.2 Overview of technical elements and enabling factors for implementation..............................6

3. TECHNICAL ELEMENTS ..........................................................................................................8

3.1 Diagnosis and case management ....................................................................................8 3.2 Integrated surveillance and outbreak preparedness .........................................................10

3.2.1 Integrated surveillance ......................................................................................11 3.2.2 Outbreak preparedness ....................................................................................12

3.3 Sustainable vector control .............................................................................................14 3.4 Future vaccine implementation ......................................................................................16 3.5 Basic, operational and implementation research .............................................................18

4. ENABLING FACTORS FOR IMPLEMENTATION ........................................................................20

4.1 Advocacy and resource mobilization .............................................................................20

4.2 Partnership, coordination and collaboration ...................................................................20 4.3 Communication to achieve behavioural outcomes............................................................21 4.3.1 Communication in outbreak response .................................................................22

4.4 Capacity-building 4.4.1 Strengthening local management capabilities for informed decision-making ............23

4.5 Monitoring and evaluation ...........................................................................................23

REFERENCES ............................................................................................................................25

ANNEXES ............................................................................................................................28

ACKNOWLEDGEMENTS ...........................................................................................................34


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FOREWORD

In just the past decade, the significance of dengue asa threat to health and a burden on health services andeconomies has increased substantially. Compared withthe situation 50 years ago, the worldwide incidence ofdengue has risen 30-fold. More countries are reportingtheir first outbreaks. More outbreaks are explosivein ways that severely disrupt societies and draineconomies. Today, dengue ranks as the most importantmosquito-borne viral disease in the world. Everywhere,the human and economic costs are staggering.

In a sense, this neglected tropical disease has taken theworld by surprise, with few coherent and coordinatedefforts, at national or international levels, undertakento hold dengue at bay and reverse these alarmingtrends. The Global strategy for dengue prevention and

control, 2012–2020, aims to correct this situation. Itanswers requests, by multiple WHO Member States, foradvice on how to move from a reactive response to anemergency situation to proactive risk assessment, earlywarning systems, and preventive measures, guided byentomological as well as epidemiological surveillance.

Above all, the Global strategy emphasizes the manynew opportunities, opened by country experiences and

recent research, also on vaccines, that can be seized toreduce morbidity and mortality, rationalize the diseaseresponse, and build capacities that increase resilienceto future outbreaks. To this end, the document alsoserves as an investment case, spelling out the steps thatcan be taken to improve risk assessment and mapping,stockpiling and logistics, surveillance and diagnosticcapacity, behavioural and social interventions, and riskcommunication.

A complex disease like dengue demands a multi-pronged response that engages government ministries

well beyond the healthsector. The Globalstrategy promotescoordinated action amongmultisectoral partners,an integrated approachto vector management,and sustained controlmeasures at all levels.Its guiding principle is toharmonize prevention,entomological and epidemiological surveillance, andcase management with existing health systems, ensuringthat efforts are coherent, sustainable, cost-effective andecologically sound.

This is a global strategy for a global threat. As wehave learned, dengue and its vectors travel wellinternationally. I challenge all partners to study thestrategy, define their role, and engage with a fullyjustified sense of urgency. As the strategy demonstrates,doing so will be highly rewarding. The overall messageis upbeat and encouraging. Despite the complex clinicalmanifestations of this disease, its management is relativelysimple, inexpensive and highly effective in saving lives,

provided correct and timely interventions are instituted.When these interventions are in place, mortality fromdengue can be reduced to zero. Let us make this ouroverarching – and broadly shared – goal.

Dr Margaret ChanDirector-General

World Health Organization


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EXECUTIVE SUMMARY

and training health personnel, along with appropriatereferral systems, at primary health-care levels.

Dengue morbidity can be reduced by implementingimproved outbreak prediction and detection throughcoordinated epidemiological and entomologicalsurveillance; promoting the principles of integratedvector management and deploying locally-adaptedvector control measures including effective urban andhousehold water management. Effective communicationcan achieve behavioural outcomes that augmentprevention programmes.

Research will continue to play an important role inreversing the trend in dengue, a neglected tropicaldisease, by improving methods and systems for

surveillance, prevention and control.Reversing the trend requires commitments andobligations from partners, organizations and countries,as well as leadership by WHO and increased funding.Fund-raising is probably best addressed by a combinedeffort, with consideration for dengue as a public healthproblem in countries with substantial local and nationalfunding resources that must be effectively channelled

through sound technical support. Dengue preventionand management can now exploit opportunitiespresented by promising advances in vector controltechnology interventions, diagnostics, prognosticsystems for triage, evidence-based clinical interventionsand candidate vaccine developments. In order torealize these opportunities, we need to ensure they areimplemented, coordinated and adequately resourced.

Dengue is a major public-health concern throughouttropical and sub-tropical regions of the world. It is themost rapidly spreading mosquito-borne viral disease,with a 30-fold increase in global incidence over thepast 50 years. The World Health Organization (WHO)estimates that 50–100 million dengue infections occureach year and that almost half the world’s populationlives in countries where dengue is endemic. Whiledengue is a global concern, with a steady increase inthe number of countries reporting the disease, currentlyclose to 75% of the global population exposed todengue are in the Asia-Pacific region.

Epidemics of dengue result in human suffering, strainedhealth services and massive economic losses. In somecountries, the burden of dengue is comparable to that

of tuberculosis and other communicable diseases withhigh disease burdens; unexpected surges in cases andthe challenge to health systems of triaging thousands ofcases without knowing which severe cases will requirehospital care are additional challenges. There has not,however, been concerted action against dengue, andthe 1995 WHO strategy1 warrants revision in the lightof new advances. This Global strategy for dengueprevention and control, 2012–2020 aims to address

this need.

The goal of the global strategy is to reduce the burden ofdengue. The specific objectives are to reduce mortalityand morbidity from dengue by 2020 by at least 50%and 25% respectively (using 2010 as the baseline).These objectives can be achieved by applying existingknowledge.

Dengue mortality can be reduced by implementingearly case detection and appropriate managementof severe cases; reorienting health services to identifyearly cases and manage dengue outbreaks effectively;

1 WHO (1996). Report of the consultation on key issues in dengue vectorcontrol towards the operationalization of a global strategy, WHO, Geneva,6–10 June 1995 . Geneva, World Health Organization(CTD/FIL(DEN)/IC/96.1).


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1. DENGUE: A GLOBAL THREAT –GLOBAL ANSWERS

Compared with other diseases and their respectiveburdens, dengue can cause as much or greater humansuffering than other communicable diseases in someof the most affected regions. In Latin America and theCaribbean, for example, by the 1990s dengue wascausing a similar burden of disease as meningitis,hepatitis, malaria, the childhood cluster of diseases(polio, measles, pertussis, diphtheria and tetanus) ortuberculosis (Meltzer et al., 1998). For South-East Asia,the burden of the disease was comparable with thatof meningitis, having twice the burden of hepatitis andone third of the burden of HIV/AIDS (Shepard DS etal, 2004). For Africa, there are insufficient data fromendemic countries to make even rough estimates ofburden. In a recent publication 22 countries in Africahave reported sporadic cases or outbreaks of dengue

from 1960-2010 (Amarasinghe A et al, 2011).For individual countries, the importance of dengueas disease and public health problem cannot beoverestimated, as seen in the recent explosive outbreaksof dengue in Brazil and Pakistan. In 2008, in Rio de

Janeiro State alone, an outbreak caused more than158 000 reported cases, over 9000 hospital admissionsand 230 deaths between January and April (Barreto,

2008). This situation led to the military being deployedto help in the massive response, mostly involvingimproved health-care and vector control operations.A call for international aid was later formulated(Lancet editorial, 2008) – although it is estimated that

1.1 BURDEN OF THE DISEASE

In 2012, dengue ranks as the most important mosquito-borne viral disease in the world. Outbreaks exert ahuge burden on populations, health systems andeconomies in most tropical countries of the world.The emergence and spread of all four dengue viruses(“serotypes”) from Asia to the Americas, Africa andthe Eastern Mediterranean regions represent a globalpandemic threat. Although the full global burden of thedisease is still uncertain, the patterns are alarming forboth human health and the economy.

During the past five decades, the incidence of denguehas increased 30-fold (Figure 1). Some 50–100 millionnew infections are estimated to occur annually in more

than 100 endemic countries (WHO, 2012a; Figure2 ), with a documented further spread to previouslyunaffected areas (CDC, 2010; La Ruche G et al,2010); every year hundreds of thousands of severecases arise, including 20 000 deaths (Gubler DJ,Meltzer MI, 1999); 264 disability-adjusted life yearsper million population per year are lost (Cattand P etal, 2006), at an estimated cost for ambulatory andhospitalized cases of US$ 514–1394 (Suaya J et

al, 2009), often affecting very poor populations. Thetrue numbers are probably far worse, since severeunderreporting and misclassification of dengue caseshave been documented (Suaya J et al., 2007; BeattyME et al. 2011).


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Figure 1. Average number of dengue and severe dengue cases reported to WHO annuallyin 1955–2007 and number of cases reported in recent years, 2008–20102500000

2000000

1500000

1000000

500000

0

N u m b e r o f c a s e s

55–59 60–69 70–79 80–89 90–99 00–07 2008 2009 2010

Period of year

908 15497

122174

295554

479848

1279668

1451083

2204516

925896

Figure 2. Distribution of global dengue risk (determination of risk status based on combinedreports from WHO, the United States Centers for Disease Control and Prevention, Gideon online,ProMED, DengueMap, Eurosurveillance and published literature (Simmons CP et al, 2012).

Suitability for Dengue

Transmission

High suitability

Low suitability

Unsuitable or nonendemic


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US$1 billion was already being spent at the nationallevel on dengue prevention and control. Despite thesecontrol efforts, in 2010 there were more than 1.2million reported dengue cases in Brazil (CONASS,2011), which is only one country cited as an exampleof the worsening global situation (Figure 3). Annex 2describes this worsening situation in five of WHO’s sixregions; Annex 3 details its underlying causes.

Given the importance of the global dengue epidemic,with its staggering human and economic costs, aninternational effort to reduce morbidity and mortality is

long overdue. As a neglected tropical disease, little orno globally coordinated efforts have been undertaken.New opportunities to overcome the disease now makesuch an effort feasible.

The 2005 revision of the International Health Regulations(IHR) (WHO, 2005a), adopted by the Fifty-eighthWorld Health Assembly (resolution WHA58.3), includesdengue as an example of a disease that may constitute

a public health emergency of international concern,with implications for health security due to disruptionand rapid epidemic spread beyond national borders.Implementation of the IHR (2005) obliges countriesto take routine and specific actions to build resilienceagainst such epidemic-prone diseases. Such actionsrequire investment in surveillance and preparednesscapacity for early detection and reporting of diseaseoutbreaks, and carrying out robust and timely public

health responses for their containment and mitigation,including cross-border and wider internationalinformation sharing and collaboration. Hence, nationalcommitments to dengue control are consistent with theaims and requirements of the IHR (2005). Annex 3

highlights the global commitment to dengue preventionand control, as articulated in resolutions of the WorldHealth Assembly and related resolutions.

This global strategy addresses the necessary steps andopportunities for investment in order to achieve theobjective of reducing mortality and morbidity causedby dengue.

1.2 REVERSING THE TREND

This global strategy provides the technical elements andenabling factors for implementation that are necessaryto reverse the growing trend in the number of denguecases. Applying existing knowledge for dengueprevention and control will require collaboration amongpartners, organizations and countries, leadership byWHO and increased funding.

Dengue mortality can be reduced by implementing

early case detection and referral systems for patients;managing severe cases with appropriate treatment;reorienting health services to cope with dengueoutbreaks; and training health personnel at all levels ofthe health system.

Dengue morbidity can be reduced by implementingimproved outbreak prediction and detection throughcoordinated epidemiological and entomological

surveillance; promoting the principles of integrated vectormanagement; deploying locally-adapted vector controlmeasures, including effective urban and household watermanagement; and through communication to achievebehavioural outcomes in prevention programmes.


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Because dengue infection can cause a spectrum ofdisease manifestations, more accurate estimates ofits true burden are essential to assess the progressof prevention measures. The enhanced surveillancesystems and dedicated studies necessary for estimatingtrue burden will not be possible in all endemic countrieswithout additional investment.

Reversing the trend of the disease could be furthersupported by the anticipated availability of a denguevaccine within the next few years. Drawing on theexperiences of other vaccine-preventable vector-

borne diseases, effective surveillance, prevention andoutbreak response tools (vector control and vaccines)must continue to complement each other in reducing theburden of the disease. The main question for planningfor dengue prevention and control is therefore how to

integrate a vaccine with other prevention and controlinterventions. Increased research will play an importantrole in any strategy to reduce dengue incidencebecause, as a neglected tropical disease, dengueresearch has received relatively little support.

1.3 OPPORTUNITIES FOR INVESTMENT

Mortality from dengue can often be reduced to zeroif severely ill patients access health services in timeand receive appropriate clinical care. The technical

knowledge for achieving this objective is available:implementation depends on capacity-building.Training in all affected countries must reach thosehealth personnel involved in prevention and casemanagement of dengue. The development and use oflocally adapted public information materials can helpfamilies recognize the early warning signs of severedengue so they seek medical care promptly. Countrieswith greater experience than others could be requested

to participate in a South–South collaboration. It mightalso be necessary to assess how to reorganize a health-care services to better cope with dengue outbreaks.

With more countries experiencing recurrent and, in-somecases, large-scale dengue outbreaks, effective dengueoutbreak prevention and control depends on a coherentapproach. Intersectoral collaboration and coordinationcan formalize emergency response planning with

stakeholders from diverse government ministries (health,environment, interior, education, etc.), municipaland local authorities, public and private sectors, andprofessional, religious and community representatives.

Dengue outbreaks are also of international concern andrequire global coordination of response efforts acrossnational borders. Special needs for support includewhen countries are experiencing epidemics, when the

A hospitalized child with severe dengue


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viruses appear in previously non-endemic regions andwhen a new serotype enters an endemic area.

Investment in dengue preparedness and response,

including risk assessment and mapping, stockpilingand logistics, surveillance and diagnostic capacity,behavioural and social interventions, and riskcommunication are all essential not only for earlyoutbreak detection and rapid response, but also forimplementing the IHR (2005) requirements to manageacute public health events.

A better estimate of the true burden of the disease needsto be addressed as a priority. Improved surveillanceand the training to support it should be supported bynational governments and coordinated by WHO.

Dengue research offers a unique opportunity forinvestment. Both basic and operational research areopportunities for international organizations and fundingsources. Networks for research cooperation could offer

opportunities to rapidly advance research with limitedfunding. To raise awareness and funds, an internationaleffort led and supported by WHO is recommended.

Advocacy, fundraising, international collaboration andharmonization of regional efforts can be addressedby strong leadership from WHO and its regional andcountry offices. This should include an effort to measure

the cost of implementing the global strategy at regionaland national levels.

Figure 3. Average number of dengue cases in 30 most highly endemic countries/territoriesas reported to WHO, 2004–2010

500’000

150’000

100’000

50’000

0

4 4

7 ’ 4 6

6

B r a z i l

I n d o n e s i a

V i e t N a m

M e x i c o

V e n e z u e l a

T h a i l a n d

P h i l i p p i n e s

C o l o m b i a

M a l a y s i a

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C o s t a R i c a

S r i L a n k a

B o l i v i a

C a m b o d i a

M y a n m a r

E l S a l v a d o r

I n d i a

P e r u

P a r a g u a y

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P u e r t o R i c o

M a r t i n i q u e

G u a d a l o u p e

S i n g a p o r e

G u a t e m a l a

D o m i n i c a n R e p u b l i c

E c u a d o r

F r e n c h G u i a n a

P a k i s t a n

A r g e n t i n a

1 2 9 ’

4 3 5

9 1 ’ 3 2 1

7 5 ’ 3 5 3

6 1 ’ 6 1 2

6 0 ’ 2 0 5

5 4 ’ 6

3 9

5 3 ’ 3 0 3

4 2 ’ 5

6 8

2 5 ’ 9 7 2

1 8 ’ 9

6 7

1 6 ’ 6

3 2

1 6 ’ 2 0 7

1 5 ’ 6 1 2

1 5 ’ 2 2 5

1 5 ’ 2 0 7

1 2 ’ 6 8 3

9 9 1 7

7 8 1 0

7 7 7 6

7 7 6 8

7 7 6 1

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7 5 0 2

7 3 8 9

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6 1 8 5

5 7 8 4

5 5 8 0

4 5 0 1


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2. THE GLOBAL STRATEGY FOR DENGUE PREVENTIONAND CONTROL

2.2 OVERVIEW OF TECHNICALELEMENTS AND ENABLING FACTORSFOR IMPLEMENTATION

The global strategy promotes coordination andcollaboration among multisectoral partners, anintegrated vector management approach and sustainedcontrol measures at all levels. Its guiding principle isto harmonize prevention, surveillance (entomologicaland epidemiological) and case management withexisting health systems, such that they are sustainable,cost-effective and ecologically sound. This strategyshould pave the way for reducing dengue morbidityand mortality worldwide through strengthened localand national capabilities and regional coordination.Mobilization and allocation of resources will also be

crucial for successful implementation of the strategy(Figure 4).

2.1 GOAL AND OBJECTIVES

The goal of the global strategy is to reduce the burdenof dengue. Its specifi c objectives are:

by 2020;

by 2020;1 and

by 2015.

The target audience of the strategy is leaders in nationalcontrol programmes, research and funding organizationsand other stakeholders involved in dengue preventionand control (e.g. urban planners, water resourcesmanagers): Dengue is a global threat that requires aglobal response involving all possible partners.

1 The year 2010 is used as a baseline.

DENGUE IS ONE OF THE 17 NEGLECTED

TROPICAL DISEASES (NTD) ADDRESSED IN

THE NTD ROADMAP.

A C C E L E R A T I N G W O R K

T O O V E R C O M E T H E G L O B A L I M P A C T O F

N E G L E C T E D T R O P I C A L D I S E A S E S

E X E C U T I V E S U M M A R Y

A R O A D M A P F O R I M P L E M E N T A T I O N


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Figure 4. The global strategy for dengue prevention and control, 2012–2020

GOAL:TO REDUCE THE BURDEN OF DENGUE

OBJECTIVES:

Technical element 1:

Diagnosis and casemanagement


Integrated surveillanceand outbreakpreparedness


Sustainable vectorcontrol


Future vaccineimplementation


Basic operationaland implementation

research

ENABLING FACTORS FOR EFFECTIVE IMPLEMENTATION OF THE GLOBAL STRATEGY:


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3. TECHNICAL ELEMENTS

Laboratory confirmation of dengue virus infection isimportant. Although in practice diagnosis is often madeby clinical signs and symptoms only, dengue can beconfused clinically with other vector-borne viral andparasitic diseases, such as malaria and chikungunyaand zika viruses. Diagnosis may involve detection ofthe virus, viral nucleic acid, antigens or antibodies, ora combination of these entities. Laboratory tests using

NS1 (non-structural protein 1) antigen can provide earlydiagnosis in febrile patients. After the onset of illness,the virus can be detected in serum, plasma, circulatingblood cells and other tissues for 45 days. Duringthe acute stage of the disease, virus isolation, nucleicacid or antigen detection can be used to diagnose theinfection. At the end of the acute phase of infection,serology is the method of choice for diagnosis.Serological assays to detect specific immunoglobulinM (IgM) or immunoglobulin G (IgG) antibodies todengue virus are widely available, and WHO hastaken a leading role in coordinating the production ofstandardized panels for comparison. These assays canprovide an alternative to virus isolation or polymerasechain reaction to support the diagnosis of dengue fever.First-time (primary) dengue virus infections typically have

3.1 DIAGNOSIS AND CASE MANAGEMENT

Mortality from dengue can be reduced to almost zero byimplementing timely, appropriate clinical management,which involves early clinical and laboratory diagnosis,intravenous rehydration, staff training and hospitalreorganization. The following technical elements area prerequisite to achieving the first objective of the

strategy: to reduce dengue mortality by at least 50%by 2020.

A successful clinical outcome requires efficient and earlydiagnosis of cases provided by accurate differentialdiagnosis, rapid laboratory assessment/confirmation,and early response to severe disease. Clinical incidencedata are critical to mobilizing outbreak control. Research

to provide better diagnostics and biomarkers predictingdisease severity are urgently needed.

Dengue infection has a wide clinical spectrum thatincludes both severe and mild manifestations. Manyviraemic infections may be inapparent. After theincubation period, the illness begins abruptly and isfollowed by three phases: febrile, critical and recovery(WHO, 2009). For a disease that is complex in its

manifestations, management is relatively simple,inexpensive and highly effective in saving lives providedcorrect and timely interventions are instituted. The keyis early recognition and understanding of the clinicalproblems during the different phases, leading to arational approach to case management and a goodclinical outcome. This is especially so for the treatmentof plasma leakage with oral or intravenous rehydration.For mortality from dengue, investigations are necessary

to establish the primary cause of deaths (includingautopsies).

MORTALITY FROM DENGUE CAN BE

REDUCED TO ALMOST ZERO BY

IMPLEMENTING TIMELY, APPROPRIATE

CLINICAL MANAGEMENT, WHICH INVOLVES

EARLY CLINICAL AND LABORATORY

DIAGNOSIS, INTRAVENOUS REHYDRATION,

STAFF TRAINING AND HOSPITAL

REORGANIZATION.


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a stronger and more specific IgM response; subsequent(secondary) infections show a weaker IgM response buta strong IgG response. These differing IgM responsepatterns to infection underscore the need to evaluate

the sensitivity and specificity of commercially availabletests, especially for diagnosis of secondary denguevirus infections. Research is necessary, however, forimproved and less expensive dengue diagnostics.

Activities (triage and management decisions) at theprimary and secondary care levels, where patients arefirst seen and evaluated, are critical in determining theclinical outcome of dengue (Table 1). A well-managedfront-line response not only reduces the number ofunnecessary hospital admissions but also saves the livesof severe dengue patients. Early notification of denguecases seen in primary and secondary care facilities

as well as commonly accepted definition of outbreakindicators (“triggers”) are crucial for identifying outbreaksand initiating an early response. Systems of referenceand counter-reference between different levels of health-

care delivery services need to be established. Thereare no biomarkers for predicting which admissions arelikely to develop severe disease, but studies to establishthe predictive value of clinical and laboratory “warningsigns” for severe dengue are under way. Research isnecessary also for the treatment of plasma leakage withco-morbidities and in pregnancy.

Training is a crucial element in all areas of dengue casemanagement, but especially for training of all medicaland non-medical staff involved in dengue clinicalmanagement. Factors such as staff turnover and careerpath should be considered when planning the frequency

Primary health centres District centres Reference centre

Dengue diagnostic tests

– Virus culture +

– Nucleic acid detection +

– Antigen detection + + +

– Serology

Other functions

– Training and supervision + +

– Quality assurance + + +

– Surveillance activities + + +

– Outbreak investigations + – Referral of problem specimens + + +

– Investigation of problem specimens +

Table 1. Possible levels of dengue diagnostic tests and other functions in health centres


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of such training. Communities should be made awareof early signs and symptoms in order to improve theirhealth-care-seeking behaviour.

In order for countries to achieve zero mortality fromdengue, a country must:

Improve case management and diagnosis to preventdeaths from dengue

for dengue with warning signs and severedengue;

appropriate interventions especially carefulintravenous rehydration and a greater evidencebase for interventions.

Improve capacities to facilitate a reduction in theburden of the disease

access and triage in endemic countries to prevent

dengue deaths;

managing outbreak situations;

both the private and the public sector;

material, including dengue courses;

health implications, bearing in mind thechallenges of widespread implementation.

3.2 INTEGRATED SURVEILLANCE ANDOUTBREAK PREPAREDNESS

Surveillance is a critical component of any dengue

prevention and control programme because it provides theinformation necessary for risk assessment and programmeguidance, including epidemic response and programmeevaluation. This technical element of the global strategy

plays an important role in implementing and measuringits objectives, especially the objective of improving theestimate of the burden of dengue by 2015.

The overall objectives of public health surveillance thatare most applicable to dengue are:

intervention;

data for the assessment of its social and economicimpacts on affected communities;

dengue over time and geographically;

collaborate where possible with monitoring ofother water, sanitation and hygiene-relateddiseases;

and control programmes; and

the basis of lessons learnt from programmeevaluation.

Crowded hospital wards during a dengue outbreak


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Surveillance can utilize both passive and active datacollection processes, as well as those of event-basedsurveillance (further details in section 4.5), and alsoinformation related to social and economic impact. It

is fundamental for setting goals and evaluating success.Understanding the spatial and temporal distributionof dengue cases and the entomological correlatesof risk in given situations would allow planners todeploy resources to areas where they would have thegreatest impact on reducing the disease. Although bothentomological and epidemiological surveillance datahave often been collected in countries, there are fewinstances in which health services integrate and fullyutilize such information to control an outbreak andprevent its expansion. Surveillance activities should,ideally, include the rapid detection of human infectionsupported by valid clinical and laboratory diagnosis,vector surveillance, and monitoring of environmentaland social risk factors for dengue epidemics to ensurethat increased dengue transmission is detected earlyand that the response is rapid and appropriate. In order

to achieve dengue surveillance, a country should:Improve surveillance to enhance reporting, preventionand control of dengue

surveillance indicators – for clinical reasons,a minimum set of indicators should be reportingthe number of dengue cases with clinical

diagnosis, severe dengue cases and the numberof dengue deaths. According to countrynecessities, further indicators may be collected;

risk indicators, including mosquito breeding sites(i.e. household water storage containers, poorurban water drainage) and appropriate

environmental control measures that areassociated with lower mosquito indices (i.e.tightly fitting water storage lids, presence offish or other biological control measures, andregular cleaning containers (Phuanukoonnon, etal., 2005);

sentinel sites should be established and age-

stratified seroprevalence and burden of disease(including economic costs) studies should beinitiated. Serotype changes should be monitoredcontinuously.

3.2.1 INTEGRATED SURVEILLANCE

The surveillance system for dengue should be a part

of the national health information system, with a set ofcore indicators monitored at various levels of the healthadministration. Such a health information system is “anintegrated effort to collect, process, report and use healthinformation and knowledge to influence policy-making,programme action and research”1. Data quality alsoneeds to be monitored and assessed periodically. Somecountries already have a routine health informationsystem and a parallel epidemic disease monitoringsystem for greater efficiency and decision-making atlocal, provincial, national and regional levels.

THE SURVEILLANCE SYSTEM FOR DENGUE SHOULD BE A PART OF THE NATIONAL HEALTH

INFORMATION SYSTEM, WITH A SET OF CORE INDICATORS MONITORED AT VARIOUS LEVELS OF

THE HEALTH ADMINISTRATION.

1 Health Matrix Network is a WHO-hosted global partnership dedicated tostrengthening health information.


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A harmonized effort across national dengue surveillancesystems is needed to obtain the critical data of thedisease’s burden necessary to assess progress inreaching mortality and morbidity reduction goals.The data currently generated by national surveillanceprogrammes are highly variable and in some known

endemic regions, such as Africa, almost no data existon incidence.

Using a tiered system, detailed serotype-specificincidence data could be obtained from a small numberof local, population-based studies at well-characterizedsites in different regions of the world. The next levelof data could come from sentinel hospitals with high-quality diagnostic capabilities that capture dengue

cases from a broader geographical range. Country-wide dengue infection data could be obtained withuniversally standardized syndromic methods and clinicaldiagnosis, when possible. Using data from this tieredsystem, national and regional estimates of diseaseburden could be extrapolated from data collected inthe different catchment systems. Efforts should focus oncapturing the entire spectrum of disease (suspected,laboratory confirmed and severe cases of dengue).

3.2.2 OUTBREAK PREPAREDNESS

Outbreak preparedness is an important technical andoperational element of the overall strategy. An effectiveresponse is based on well-developed contingencyplans that are broadly disseminated and thoroughlyunderstood and pre-tested before an epidemic. The planshould include relevant sectors and agencies. Importantresponse components will include the logistic capabilityto deal with the inflow of patients, medical supplies andfacilities, administration, political issues, vector control

efforts and communication with participating partnersand the mass media.

The dengue response plan should clearly articulate itsaims, objectives and scope, the lead (coordinating)agency, the organizational links with other agencies that

have direct responsibility for implementing aspects of theplan, and the “support” agencies (for example, socialwelfare agencies) that may be more involved in therecovery phase after an epidemic. Each agency shouldbe assigned specific roles and responsibilities under theplan, and costs and resources should be identified.

The 10 priority areas for planning dengue emergencyresponse, adapted from Rigau-Pérez and Clark (2005),

are to:

1. Establish a multisectoral dengue action committee

2. Formalize an emergency action plan

3. Enhance disease surveillance

4. Perform diagnostic laboratory testing

5. Enhance vector surveillance and control

6. Protect special populations and reduce the

impact of environmental determinants 7. Ensure appropriate patient care

8. Engage the community and relevant professionalgroups about dengue control as well as theirparticipation in dengue prevention and control

9. Investigate the epidemic

10. Manage the mass media.

Lessons learnt from large numbers of international publichealth emergencies led to the revision of the IHR. TheIHR (2005) emphasizes national capacity to monitor,

A HARMONIZED EFFORT ACROSS NATIONAL DENGUE SURVEILLANCE SYSTEMS IS NEEDED FOR

TO OBTAIN THE CRITICAL DATA OF THE DISEASE’S BURDEN NECESSARY TO ASSESS PROGRESS IN

REACHING MORTALITY AND MORBIDITY REDUCTION GOALS.


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identify and assess risks, and target preparednessplanning and operational capacity, in order to rapidlydetect outbreaks and respond in a timely manner.

Dengue activity may require consultation with, ornotification to, WHO under the IHR (2005) (WHO,2005a), depending on the risk assessment. Forexample, dengue activity may warrant communication

with WHO in instances such as the first confirmationof locally-acquired dengue in a previously disease-freearea, a newly predominant serotype or vector, atypicalclinical presentations or excessively high case-fatalityrates.

Rapid verification, risk assessment and information-sharing are critical to WHO coordination of the GlobalOutbreak Alert and Response Network (GOARN) andeffective international response to major outbreaks. Atthe request of a member State, WHO rapidly deploysinternational GOARN teams of experts to the affectedareas to integrate and coordinate activities in supportof national efforts. There is recognition of the strongtechnical leadership and unique role of nationaland international nongovernmental organizations,particularly in reaching poor populations. This rapid

response could be used as a mechanism to build globaland local capacity to improve preparedness and reducefuture vulnerability:

For countries in which dengue is endemic, theoverall aim of an emergency plan is to reduce the riskof dengue transmission and to strengthen and sustaincontrol measures thereby minimizing the clinical, socialand economic impacts of the disease. Monitoring and

evaluation should be planned and implemented toassess the impact of all interventions.

For countries in which dengue vectors are presentwithout circulating virus, risk management plansshould focus on strategies to reduce the risk oftransmission. These should include rapid investigationof sporadic cases (clinically suspected or laboratoryconfirmed) to determine whether they are importedor locally-acquired, regular monitoring of vectors andtheir abundance (particularly in regions with recorded

or suspected cases), social mobilization and integratedvector management. Once a locally-acquired case isconfirmed, the response may be escalated to epidemicresponse to prevent further spread and/or interruptionof transmission.

For countries in which there is risk of introducingdengue vectors, the focus of preparedness planningand activities should be on entomological surveillance

AN EFFECTIVE RESPONSE IS BASED ON WELL-DEVELOPED CONTINGENCY PLANS THAT ARE BROADLY

DISSEMINATED AND THOROUGHLY UNDERSTOOD AND PRE-TESTED BEFORE AN EPIDEMIC.

Space spraying for dengue vector control


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EFFECTIVE VECTOR CONTROL MEASURES ARE CRITICAL TO ACHIEVING AND SUSTAINING

REDUCTION OF MORBIDITY ATTRIBUTABLE TO DENGUE. PREVENTIVE AND VECTOR CONTROL

INTERVENTIONS AIM TO REDUCE DENGUE TRANSMISSION, THEREBY DECREASING THE INCIDENCE

OF THE INFECTION AND PREVENTING OUTBREAKS OF THE DISEASE.

at points of entry (ports, airports, ground crossing)and education of the health-care providers and thecommunity about the risk of dengue in travellers, and itsdiagnosis and reporting requirements.

3.3 SUSTAINABLE VECTOR CONTROL

Effective vector control measures are critical to achievingand sustaining reduction of morbidity attributable todengue. Preventive and vector control interventions aimto reduce dengue transmission, thereby decreasing theincidence of the infection and preventing outbreaks ofthe disease.

The mosquito Aedes aegypti is the primary vector ofdengue. It has evolved to mate, feed, rest and lay eggsin and around urban human habitation. Aedes aegypti is a daytime feeder; its peak biting periods are earlyin the morning and before dusk in the evening. FemaleAedes aegypti frequently bites multiple people during

each feeding period.

The mosquito Aedes albopictus, a secondary denguevector in Asia, has spread to North America and Europelargely due to the international trade in used tyres (abreeding habitat) and other goods (eg. lucky bamboo).Its spread is due to its tolerance to temperatures belowfreezing; it is able to hibernate and take shelter inmicrohabitats. Apart from these two well-established

species, Aedes polynesiensis (in French Polynesia,the Cook Islands and Wallis and Futuna) and Aedes

scutellaris (in New Guinea) have been shown to bevectors. (Rodhain F, Rosen L, 1997). Aedes hensilli wasidentified as an epidemic vector in the Federated Statesof Micronesia (Savage et al., 1998). Aedes furcifer

and Aedes luteocephalus are among probable sylvaticvectors in western Africa.

There are well-documented historical examples ofboth yellow fever and dengue being eliminated orsignificantly reduced through Ae. aegypti control. Morerecently, Singapore and Cuba greatly reduced denguetransmission by enacting anti-Aedes legislation andthrough sustained actions against the vector (Gubler DJ,2011).

Epidemic-prone countries typically initiate vector controlmeasures after the onset of an epidemic which is toolate to achieve significant impact. Endemic countries,on the other hand, too often carry out routine short-terminterventions, which are neither sustained nor evaluated.Any successful control effort must be centred on the

ability to sustain the intervention with sound monitoringand evaluation.

Control of dengue vectors has mainly been approachedby source reduction: the elimination of containers thatare favourable sites for oviposition and development ofthe aquatic stages. This can sometimes be accomplishedby fitting lids or covers on containers or by killing theaquatic stages using insecticides. Some insecticides

combine persistence in efficacy (thus requiring lessfrequent re-treatment) with absence of taste when


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applied to potable water, and may improve communityacceptance. Carrying out pupal surveys in humanhabitations can identify which containers are mostproductive; treating only these productive containers

can be as effective as dealing with all containers (Tun-Lin W et al, 2009). The ability of the vector, howeverto exploit unconventional sites to lay eggs should notbe underestimated. In the past few years, for example,breeding has been found in septic tanks in Puerto Ricoand in rooftop gutters in Singapore. The degree towhich immature populations must be reduced, shortof total elimination, to significantly reduce incidence isseldom known for any endemic locality, compromising apotentially useful index of entomological surveillance.

Although insecticide space-spraying is recommendedfor vector control in epidemics, its efficacy in othersituations has not been well documented (Ekpereonne Eet al, 2010). Delivery of indoor space spraying is highlylabour-intensive and, in most locations, it is impracticalin the event of an outbreak.

Residual surface treatments of insecticides are intendedto reduce the density of vectors and their longevity.Although indoor residual spraying is frequentlysuccessful against malaria vectors, its effect on Aedes,which often do not rest on interior walls is uncertain.Further research is required on the effect of residualinsecticides on curtains, container covers, screens andother materials which often have good community

acceptability. In general, methods that improve theability to deliver persistent treatments more rapidly andefficiently into large urban communities in a sustainedway are urgently needed.

The evolution and spread of resistance to insecticidesis a major concern for the control of dengue vectors.Bioassay data demonstrate that resistance toorganophosphates (temephos) and pyrethroids is

widespread in Ae. aegypti , and resistance has also

been reported in Ae. albopictus. Assessing the impactof insecticide resistance on vector control is complicatedby variations in the methodology used to measure andreport resistance, and by the lack of studies on the

epidemiological consequences of insecticide resistance(Ranson H et al, 2009). Monitoring resistance isnecessary to ensure that effective insecticides are beingused and that changes in insecticide policy are basedon sound scientific data. Monitoring must be wellcoordinated at the local level with other vector-bornedisease control programmes and usage of insecticidesin agriculture.

Innovative vector control tools are badly needed(Morisson AC et al., 2008) .Some recent developmentsin the pipeline are: insecticide-treated materials;lethal ovitraps; spatial repellents; genetically modifiedmosquitoes; and Wolbachia-infected Aedes. Some ofthese new tools could play a significant role in long-termdengue prevention and control strategies of Member

Used tires proliferate dengue vector breeding


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COUNTRIES SHOULD ADOPT THE

INTEGRATED VECTOR MANAGEMENT

APPROACH TO VECTOR CONTROL ASPROMOTED BY WHO (WHO, 2004,

2012C). DEFINED AS A RATIONAL

DECISION-MAKING PROCESS TO OPTIMIZE

THE USE OF RESOURCES FOR VECTOR

CONTROL, IT AIMS TO IMPROVE EFFICACY,

COST EFFECTIVENESS, ECOLOGICAL

SOUNDNESS AND SUSTAINABILITY OFVECTOR CONTROL INTERVENTIONS.

DENGUE VECTOR CONTROL IS MOST

AMENABLE TO THE IMPLEMENTATION OF

THE PRINCIPLES OF INTEGRATED VECTOR

MANAGEMENT, WHICH ENSURE JUDICIOUS

USE OF INSECTICIDES IN COMBINATION

WITH OTHER PREVENTION AND CONTROLINTERVENTIONS.

States. Periodic monitoring and evaluation of all stagesof vector suppression must ensure that appropriatestandards are met; they are crucial to maximize efficacyand efficiency of the global strategy. Methods to assess

the impact of vector interventions need to be establishedwhile those for risk assessment and response improved.Reliable, practical, standardized vector surveillancemethods and entomological correlates of virustransmission (for example, entomological inoculationrate) are required.

Countries should adopt the integrated vectormanagement approach to vector control as promotedby WHO (WHO, 2004, 2012c). Defined as arational decision-making process to optimize the useof resources for vector control, it aims to improveefficacy, cost effectiveness, ecological soundness andsustainability of vector control interventions. Denguevector control is most amenable to the implementation ofthe principles of integrated vector management, whichensure judicious use of insecticides in combination with

other interventions.

3.4 FUTURE VACCINE IMPLEMENTATION

The availability of a safe, efficacious and cost-effectivevaccine would significantly alter the concept for dengueprevention. As the global spread of dengue persists,

vaccine development has received increasing interestand support by researchers, vaccine manufacturers,policy-makers and funding agencies. But as has beenrepeatedly demonstrated, even a perfect vaccine is onlyas good as our ability to deliver it. Planning for the mosteffective implementation of vaccine delivery is a technicalelement that should begin to be addressed now.

The most advanced vaccine candidate, which is based

on live-attenuated chimeric yellow fever-dengue virus,has progressed to phase III clinical trials (Guy B et al.,2011). Several other live-attenuated vaccines, as well

as a subunit and a DNA vaccine, are in earlier stagesof clinical development (Coller BA, 2011). Additionaltechnological approaches, such as virus-vectored and

inactivated vaccines, are under evaluation in preclinicalstudies (Schmitz J et al., 2011). Challenges to vaccinedevelopment include the need to provide protectionagainst all four dengue viruses, as well as resolvingquestions about the immune correlates of protection.While proof of concept of vaccine efficacy is currentlystill missing, successful progression of ongoing efficacytrials could lead to the availability of a vaccine in 2–4

years.

Current dengue prevention and control strategies shouldtherefore include vaccines as an important element to


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anticipate and prepare for. This includes preparing forfuture decision-making on vaccine introduction and use,considering the integration of vaccines with other toolsfor dengue prevention and control, and investments in

surveillance systems and safety monitoring of vaccines.

In order to provide guidance to national regulatoryagencies and manufacturers on vaccine evaluationand registration, WHO has published Guidelines onthe quality, safety and efficacy of dengue tetravalentvaccines (live, attenuated) (WHO, 2012b). Theseguidelines cover issues concerning manufacturing andquality control, pre-clinical development, and clinical

evaluation of the first generation of live-attenuateddengue vaccines. Updates will likely be requiredas second-generation vaccines become available,which may be based on different technologies. Long-term safety and effectiveness of dengue vaccines willrequire particularly careful assessment. This includesthe follow-up of vaccine trial participants for several

years’ post-vaccination, special post-licensure studies,and surveillance systems capable of monitoring vaccineimpact on dengue epidemiology and its disease burden.In anticipation of vaccine licensure and introductionin at least some endemic countries in the near-termfuture, there is a need to ensure strong regulatory andsurveillance capacity in endemic countries.

Evidence-based decision-making on the introduction ofvaccines and their use will require not only reliable data

on vaccine product characteristics (e.g. safety, efficacy,cost) but also information on effective vaccinationstrategies, their likely impact on disease burden andcost effectiveness. Moreover, various issues relatedto vaccine implementation (e.g. integration into thenational immunization programme; logistics of vaccinestorage and transport; financing and supply) will haveto be addressed (WHO, 2005b).

Assuming proof of concept is met, some of thechallenges for vaccine delivery are already evident: (i)the population at risk of dengue is huge and occurs

throughout the tropics. It will be necessary for endemiccountries to have rational means for deciding whichsegments of the population to protect when nationalresources or vaccine supply are limited; (ii) ease of

delivery and cost will limit implementation. Ideally, avaccine will be administered as a single dose, willprotect against all four viruses, and will have a longduration of efficacy with no significant side-effects. Inreality, some or all of these ideals will not be met. Avaccine that requires multiple doses, for example,or which cannot be incorporated in an expandedprogramme on immunization will require supplementaryinvestments into delivery infrastructure; (iii) post-approval

studies, monitoring of vaccinated populations andstrong regulatory competency in dengue-endemiccountries will be needed; (iv) the role of vector control,surveillance and case management in enhancing theimpact of the vaccine must be determined. Althougheach country will require a different combination, somebasic guidance for decision-making must be developed;(v) there is a possibility that dengue could be eliminated

from some regions, such as islands or low endemicareas. How and where such a special target could bereached should be determined.

development and implementation of vaccinationstrategies include the choice of target populations(e.g. age groups, location), delivery approaches(e.g. routine immunization, catch-up campaigns),

vaccination schedules and overall immunizationcoverage in the population.

been developed, which may contribute toinforming the design of optimal dengueimmunization strategies (WHO, 2011;

Johansson MA, Hombach J, Cummings DA,2011).

vaccination strategies are well integrated withother interventions for dengue prevention andcontrol.


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3.5 BASIC, OPERATIONAL ANDIMPLEMENTATION RESEARCH

Supporting all objectives of the strategy, and basic,

operational and implementation research are needed.All partners should emphasize the value of research,and promote and support the efforts at all levels.

Dengue prevention and control programmes wouldbe empowered with more effective tools. Researchshould address how the efficacy, cost-effectiveness,sustainability and scaling up of existing and promisingnew control methods can be enhanced. New diagnostictools and means of vector control are needed. Moreeffective approaches to fostering sustained communityparticipation are also needed. Some core areas forresearch are:

cases through locally-adapted training curriculathat increase accurate clinical diagnosis.

Research is also needed on, for example,alternate methods of fluid management, dealingwith dengue in pregnancy and with co-morbidities, and better guidance on use of bloodproducts.

be used at point-of-care clinics to diagnosecases as early as possible; improving andstandardizing quality control of currently available

and future rapid diagnostic tests; identifyingbiomarkers of severe disease.

response by national health services, includingmodels for the rapid relay and analysis ofinformation. Means of improving the coordinationof vector control and medical assets duringpreparedness and response.

risk for dengue outbreaks as early warning signals.Defining risk factors for human infection, forexample, the contribution of people with

asymptomatic infections to transmission and/orthe proximity of Ae. aegypti breeding sitesto populations. Defining the relationshipbetween mosquito parameters and transmissionrisk, and between vector interventions andepidemiological outcomes. Establishingaction thresholds according to the epidemiologicalsituation and developing tools for managingoutbreak preparedness and response.

evaluating the impact of virus population structure,urbanization and other land-use changes, humanbehavioural interactions and climate parameterson dengue epidemiology. Developing modelsto quantify combined vaccine and vector controlapproaches on transmission.

of cost-effective implementation strategies,scaling-up of successful local interventions,evaluation protocols for effectiveness of humanand entomological surveillance, householdwater management, conditions favouringsustained human behavioural change, models foridentifying vulnerable groups or geographicallocalities, and evaluation of settings in selectingapproaches (e.g. schools, workplaces, religious

establishments).

among dengue vectors using non-insecticidalmethods, rotation of insecticides, standardizingcontemporary methods for detection andmanagement of resistance, assessing the impactof resistance on dengue prevention programmes,and monitoring the role of unregulated and


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broad-spectrum usage of insecticides (e.g.agricultural pest, nuisance fly control, householdproducts) and its possible role in insecticideresistance.

and control outbreaks of dengue by non-insecticidal methods (e.g. effective urbandrainage), suppression of mosquito populationsand their possible elimination through attractanttraps, repellents, genetically modified mosquitoes,Wolbachia-based approaches, , insecticide-treated materials and rapid delivery of insecticideinto houses where mosquitoes rest and bitepeople.

MONITORING RESISTANCE IS NECESSARY TO ENSURE THAT EFFECTIVE INSECTICIDES ARE BEING

USED AND THAT CHANGES IN INSECTICIDE POLICY ARE BASED ON SOUND SCIENTIFIC DATA.

and their integration with existing interventions.In particular there is a need to address gapsin our knowledge about vaccine efficacy, long-

term safety and effectiveness, immune correlatesof protection, possible booster needs, herdimmunity and co-administration with othervaccines; it is important to begin to developoptimal immunization strategies (includingtarget populations, delivery approaches,vaccination schedules, immunization coverage);and strategies for integrating dengue vaccinationwith other dengue prevention and control

methods.

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4. ENABLING FACTORS FOR IMPLEMENTATION

implementing the strategies and plans for the Americasand Asia-Pacific regions; and it should also assist inbuilding relevant capacities in the African, EasternMediterranean and European regions. WHO is uniquelyplaced to encourage and facilitate closer integrationof dengue surveillance and epidemic mitigation withthe syndromic approaches required by the IHR (2005)(WHO, 2005a), particularly as it pertains to a common

case definition and to harmonized data collection,analysis and dissemination. Advocacy packages forpolitical support and resource mobilization need to bedeveloped at regional and country levels. It would beideal to focus efforts on dengue by using high-profilepublic figures as champions for the cause at national levelsand utilize existing regional and global collaborationsto promote the effort widely. An example of a regionalinitiative is the ASEAN (Association of South East Asian

Nations) countries’ decision to commemorate “ASEANDengue Day” on 15 June every year. Special advocacycampaigns should target the public sector, the privatesector (including water and sanitation and relatedinfrastructure) and sectors involved in developing newproducts for dengue prevention and control.

4.2 PARTNERSHIP, COORDINATION ANDCOLLABORATION

Dengue is the classic 21st century disease, driven byan urban adapted mosquito and easily transportedby infected people or the vector through increasing

Successful implementation of the global strategyrequires five enabling factors: (i) advocacy andresource mobilization; (ii) partnership, coordinationand collaboration; (iii) communication to achievebehavioural outcomes; (iv) capacity-building; and (v)monitoring and evaluation. At the national level, theseelements require greater collaboration at all levels ofgovernment and other sectors; globally, implementation

requires concerted action by Member States, effectiveglobal leadership and appropriate engagement of allrelevant stakeholders.

4.1 ADVOCACY AND RESOURCEMOBILIZATION

For dengue prevention and control there is very littleinternational advocacy or successful funding efforts.Whereas some research organizations are successfullyraising funds for focused research work, almost nomoney is available for international control efforts.This funding gap affects all areas where internationalresponse could help, such as outbreak preparednessand response, development of training material,organization of training courses and support of research

networks.WHO should lead the global advocacy effort. Itshould coordinate with regional and country offices todevelop and implement advocacy plans to increase thepolitical support and resource mobilization needed for

SPECIAL ADVOCACY CAMPAIGNS SHOULD TARGET THE PUBLIC SECTOR, THE PRIVATE SECTOR(INCLUDING WATER AND SANITATION AND RELATED INFRASTRUCTURE) AND SECTORS INVOLVED

IN DEVELOPING NEW PRODUCTS FOR DENGUE PREVENTION AND CONTROL.

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trade, changing land use and expanding urbanization.Successful dengue control programmes are characterizedby multisectoral and interagency preparedness andresponse. Unfortunately, this is not often the case in

most countries, and this approach should be promotedand encouraged at all levels in every endemic country.Equally important, internationally, different organizationsworking in dengue control or research are often notconnected: development of networks for partnership,coordination and collaboration is highly desirable.

Dengue prevention and control needs an effectiveintersectoral approach, requiring coordination between

the lead ministry (usually the Ministry of Health) andother relevant ministries and governmental agencies, theprivate sector (including private health-care providers),nongovernmental organizations and local communities.Resource sharing is an important aspect of coordination,and is critical in emergency situations when scarce orwidely dispersed human and material resources must bemobilized rapidly and their use coordinated to mitigatethe effects of an epidemic.

Coordination with urban planning and water resourcesmanagement is especially important for preventionefforts and to reduce dengue morbidity. The projectedrapid increases in urban populations in dengue-endemiccountries further highlights the need for concurrentincreases in improved and reliable supplies of pipeddrinking-water and sanitation in order to prevent water

storage, reduce urban breeding sites and improvedrainage, including near community water collectionpoints.

Intersectoral and intra-sectoral collaboration amongpartners is key to the successful implementation ofthe global strategy. Networking facilitates a morecoordinated approach than the individual andindependent efforts of different sectors or departments,

and provides a platform for partners to resolve cross-and intra-agency issues and to share best practices

while reducing duplication of efforts. Networking fordengue control also helps to leverage the strengths ofpartners and to synergize their efforts, thereby enhancingthe effectiveness and efficiency of actions for dengue

prevention and control. Effective surveillance systems,for example, require networking among technicalagencies and personnel who collect data and processdata and who can assist in establishing sentinel sites.In many countries, inter-ministerial or inter-departmentalactivities remain a challenge due to a lack of attentionto building relationships and hierarchal structures withinthe ministry, which must be addressed at the highestpolitical level.

A dengue task force or steering committee is set up inmany countries but is often activated only at times ofepidemics. In order to effectively implement the globalstrategy, members of the taskforce should have relevanttechnical expertise and decision-making authorityand should meet regularly to evaluate and monitorprogress and provide strategic oversight. A greaterlevel of cohesion among partners will be achievedby focusing efforts on team building and improvedcommunication skills. Building partnerships withindustry and allied sectors (such as water, sanitationand infrastructure development agencies) can preventvector proliferation through product development andshared best practices. WHO needs to support effortsat harmonizing case definitions, data collection andprocessing, dissemination of data and cross-border

exchange of information among Member countries atsubregional and regional levels.

4.3 COMMUNICATION TO ACHIEVEBEHAVIOURAL OUTCOMES

Communication is integral to every activity neededto implement the technical elements in this strategy

document. Dengue cases and dengue deaths canbe reduced only through the behavioral actions of

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those responsible for designing and implementingdengue prevention and control programmes, and bythe adoption of risk reduction and health protectionbehaviors by the populations at risk. Knowledge is a

prerequisite for action but it does not always convinceand persuade people to act. Communication forBehavioural Impact (COMBI) is a systematic planningmethodology adopted by WHO to design andimplement behaviourally-focused communicationstrategies for modifying behaviours associated withdengue and other vector-borne diseases. Examplesof how COMBI might be used in dengue preventionand control programmes include enhancing community

mobilization for source reduction, appropriate use ofhousehold insecticides, appropriate and timely use ofhealth services, diagnosis and reporting of denguecases, and acceptance of dengue vaccination when itbecomes recommended.

WHO needs to advocate for behavioural outcomesto partners and Member States and should include asection on communication to achieve it in all relevantdocuments (dengue and vector-borne diseases).

Awareness and capacity should be created at allprogramme levels to support:

to identify existing behaviours that promote orimpede programme outcomes;

related to programme outcomes (e.g. bettercoordination of each technical element orintervention, programme interaction with theat-risk population); and

behaviours related to population outcomes (e.g.reduced disease, reduced deaths, craftingmessages and their dissemination through massmedia and other channels).

4.3.1 COMMUNICATION IN OUTBREAK RESPONSE

Effective communication linked to promoting specific,measurable, appropriate, realistic and time-bound

(SMART) outbreak prevention and control behavioursare vital for:

interventions and allocate resources (people,funds, supplies) so that teams on the ground mightrespond appropriately and rapidly;

from many sources needed for assessing theevent and identifying whether interventions areworking and what technical inputs are neededto bring the event under control;

teams to talk with health care workers, patients,public health officials, NGOs and responsepartners to rapidly assess the problem andimplement appropriate control and prevention

measures;

implement appropriate risk communicationstrategies to prepare national systems,stakeholders and partners for response; and

design and implement behavioural and socialinterventions that will prepare communities for

potential public health measures and to promoterisk reduction.

Training of staff at national and regional levels must becoordinated and an inventory of expertise should beavailable for use as and when needed.

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4.4 CAPACITY-BUILDING

Capacity-building has been neglected at all levels ofdengue prevention and control. Ongoing efforts, such

as training courses often are not sustained or scaled-up to the national level. Effective implementationof the global strategy requires adequate staff withaccess to appropriate equipment and facilities, andthe knowledge, competencies and skills to effectivelyexecute, monitor and evaluate the dengue controlprogramme. Programme management should bestrengthened for effective sustainable dengue preventionand control.

Social scientists and communication specialists,public health entomologists, vector control personnel,epidemiologists, diagnostic laboratory staff, and health-care personnal play essential roles and need to worktogether. Training activities, including in-service training,should be tailored to the needs of the various groupsof personnel, integrate adult learning techniques andfocus on improving the performance of multidisciplinaryteams. WHO has published guidance on severalcomponents of dengue control programmes such asdiagnosis, case management, prevention and control,and communication strategies. Efforts must be madeto adapt these documents for local needs at countryand regional levels. Wider dissemination of availablematerials would significantly benefit all stakeholders andavoid duplication of efforts (Annex 4).

4.4.1 STRENGTHENING LOCAL MANAGEMENTCAPABILITIES FOR INFORMED DECISION-MAKING

Local health systems are increasingly responsiblea wide variety of disease prevention and control

activities. However, they are generally not prepared forthe management of dengue outbreaks and resources(human, technical and financial) are insufficient. “Tabletop” or simulation exercises should be developed by

WHO for use at the local level. The sometimes longinter-epidemic periods are a challenge to maintainingresponse management expertise. Managers needsupport from their superiors so that dengue preventionand control activities continue to receive appropriateattention within the broader communicable diseasecontrol programme. Decision-makers, planners andprogramme managers have many other responsibilitiesand may not know how to prioritize control and outbreak

measures with adequate safeguard to manage potentialchanges in the epidemiology of the disease. They needaccess to a panel of technical experts to inform theirdecision-making.

Sustainability and continuity of control measures areessential. Dengue prevention and control needs amore participatory approach at the local level, andkey decision-makers need to forge partnerships withcommunity leaders for better communication andcollaboration. There is a need to recognize and usewhen possible the existing networks for respondingto public health emergencies that can extend fromgovernment to community level. Ministries of healthservices at the local level should also integrate keycomponents (surveillance, entomology, environment,communication, laboratory) for better decision-

making and efficient use of resources. In order toensure implementation and sustainability of controlprogrammes at the local level, the national regulation(on vector control or pesticides) may be adaptedto integrate surveillance and control measures asmandatory contributions of local authorities (includingcommunity leaders) to the national plan.

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4.5 MONITORING AND EVALUATION

A functional monitoring and evaluation system is vitalto the successful implementation of the dengue strategy.

Monitoring and evaluation guides the planning andimplementation of the global strategy, assesses itseffectiveness, identifies areas for improvement andoptimizes the use of resources.

Monitoring and evaluation is a very weak link in nearlyall dengue programmes and needs to be strengthenedand integrated urgently. Relevant training programmesare available at both the national and international

levels.

The combination of monitoring and evaluation allowsthe identification of successes and shortcomings, fromwhich lessons learnt, can inform decision-making.A major challenge is to identify indicators for use ateach level of the health system that can be measuredobjectively and systematically. At decentralized levelsof the system, indicators for resource use, processes,behaviour, epidemiology, and entomology need to bedeveloped by Member States.

The use of one national system to collect, analyse,interpret and use monitoring and evaluation data isencouraged to reduce the reporting burden. Improvingthe quality and consistency of information requires,common indicators, clear data collection methods, and

uniform analysis and interpretation.

WHO collects a minimum set of dengue indicators fromMember States, which include:

severe dengue,

and

The global strategy needs to standardize indicators.Although the best assessment of the dengue burden andits trends today must rely on a combination of suspectedcases and confirmed data, accurate surveillance shouldbe the ultimate goal for programmes. Routine surveillancehas two particular advantages for estimating caseincidence, spatially and through time. Data compiledannually allow for the effects of changes in the array offactors that influence dengue outbreaks and prevalence

from place to place (at the level of cities, provinces,etc.) and from year to year, especially the factorslinked to climatic variation, serotype change andcontrol interventions. For these reasons, monitoring andevaluation is critical and should be a key componentfor dengue surveillance programmes, systems thatprovide guidance and risk assessment, and outbreakresponse plans. WHO should coordinate metrics forsurveillance and assessment through the selection of

well-characterized field sites where the variables canbe defined and by developing epidemiological metricsand methods for their estimation (e.g. vector thresholds,virus prevalence and/or incidence).

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