Dengue Prevention and Control Program

BACKGROUND

Dengue is the fastest spreading vector-borne disease in the world endemic in 100 countries·

  • Dengue virus has four serotypes (DENV1, DENV2, DENV3 and DENV4)
  • First infection with one of the four serotypes usually is non-severe or asymptomatic, while second infection with one of other serotypes may cause severe dengue.
  • Dengue has no treatment but the disease can be early managed.
  •  The five year average cases of dengue is 185,008; five year average deaths is 732; and five year average Case Fatality Rate is 0.39 (2012-2016 data).

TRANSMISSION

Dengue virus is transmitted by day biting Aedes aegypti and Aedes albopictus mosquitoes.

DENGUE CASE CLASSIFICATION AND LEVEL OF SEVERITY

  • Dengue illness is categorized according to level of severity as dengue without warning signs, dengue with warning signs and severe dengue.
  • Dengue without warning warnings can be further classified according to signs and symptoms and laboratory tests as suspect dengue, probable dengue and confirmed dengue.
  1. dengue without warning signs​​

      a.1 suspect dengue

- a previously well individual with acute febrile illness of 1-7 days duration plus two of the following: headache, body malaise, retro-orbital pain, myalgia, arthralgia, anorexia, nausea, vomiting, diarrhea, flushed skin, rash (petechial, Hermann’s sign)

        a.2 probable dengue

-  a suspect dengue case plus laboratory test: Dengue NS1 antigen test and atleast CBC (leukopenia with or without thrombocytopenia) or dengue IgM antibody test (optional) 

       a.3 confirmed dengue

- a suspect or probable dengue case with positive result of viral culture and/or Polymerase Chain Reaction (PCR) and/or Nucleic Acid Amplification Test- Loop Mediated Amplification Assay (NAAT-LAMP) and/ or Plaque Reduction Neutralization Test (PRNT)

b. dengue with warning signs

a previously well person with acute febrile illness of 1-7 days plus any of the following: abdominial pain or tenderness, persistent vomiting, clinical signs of fluid accumulation (ascites), mucosal bleeding, lethargy or restlessness, liver enlargement, increase in haematocrit and/or decreasing platelet count 

c. severe dengue

severe plasma leakage leading to

  • shock (DSS)
  • fluid accumulation with respiratory distress

severe bleeding

  • as evaluated by clinician

severe organ impairment

  • Liver: AST or ALT ≥ 1000
  • CNS: e.g. seizures, impaired consciousness
  •  Heart:and other organs (i.e. myocarditis, renal failure)

​PHASES OF DENGUE INFECTION

  1. Febrile Phase
  •  Usually last 2-7 days
  • Mild haemorrhagic manifestations like petechiae and mucosal membrane bleeding (e.g nose and gums) may be seen.
  • Monitoring of warning signs is crucial to recognize its progression to critical phase.
  1. ​Critical Phase
  • Phase when patient can either improve or deteriorate.
  • Defervescence occurs between  3 to 7 days of illness. Defervescence is known as the period in which the body temperature (fever) drops to almost normal (between 37.5 to 38°C).
  • Those who will improve after defervescence will be categorized as Dengue without Warning Signs, while those who will deteriorate will manifest warning signs and will be categorized as Dengue with Warning Signs or some may progress to Severe Dengue.
  • When warning signs occurs, severe dengue may follow near the time of defervescence which usually happens between 24 to 48 hours.
  1. Recovery Phase
  • Happens in the next 48 to 72 hours in which the body fluids go back to normal.
  • Patients’ general well-being improves.
  • Some patients may have classical rash of “isles of white in the sea of red”.
  • The White Blood Cell (WBC) usually starts to rise soon after defervescence but the normalization of platelet counts typically happens later than that of WBC. 

MANAGEMENT (based on patient type)

  1. Group A- patients who may be sent home

These are patients who are able to:

  • Tolerate adequate volumes of oral fluids
  •  Pass urine every 6 hours
  • Do not have any of the warning signs particularly when the fever subsides
  • Have stable haematocrit
  1. Group B- patient who should be referred for in-hospital management

Patients shall be referred immediately to in-hospital management if they have the following conditions:

  • Warning signs\
  • Without warning signs but with co-existing conditions that may make dengue or its management more complicated ( such as pregnancy, infancy, old age, obesity, diabetes mellitus, hypertension, heart failure, renal failure, chronic haemolytic diseases such as sickle- cell disease and autoimmune diseases, etc.)
  • Social circumstances such as living alone or living far from health facility or without a reliable means of transportation.
  • The referring facility has no capability to manage dengue with warning signs and/or severe dengue.
  1. Group C- patient with severe dengue.requiring emergency treatment and urgent referral

These are patients with severe dengue who require emergency treatment and urgent referral because they are in the critical phase of the disease and have the following:

  • Severe plasma leakage leading to dengue shock and/or fluid accumulation with respiratory distress;
  • Severe haemorrhages;
  • Severe organ impairment (hepatic damage, renal impairment, cardiomyopathy, encephalopathy or encephalitis)

Patients in Group C shall be immediately referred and admitted in the hospital within 24 hours. 

LABORATORY TESTS

 

Test

Description

1.      Dengue NS1 RDT

  • Requested between 1-5 days of illness
  • Use to detect dengue virus antigen during early phase of acute dengue infection
  • Test is for free in all health centers and selected public hospitals nationwide

2.      Dengue IgM/IgG

  • Requested beyond five days of illness
  • Use to detect dengue antibodies during acute late stage of dengue infection (IgM) and to determine previous infection (IgG)
  • May give false positive result due to antibodies induced by dengue vaccine
  • May cross react with other arboviral diseases such as Chikungunya and Zika
  • DOH augmentation is limited to selected government hospitals only

3.      Polymerase Chain Reaction (PCR)

  • One of the gold standard laboratory tests to confirm dengue virus.
  • Molecular based test confirmatory test
  • Available only in dengue sub-national and national reference laboratories

4.      Nucleic Acid Amplification Test- Loop Mediated Isothermal Amplification Assay (NAAT-LAMP)

  • A novel molecular-based confirmatory test used to detect dengue virus.
  • Work just like PCR but cheaper and simpler in nature.
  • In the pipeline to be introduced under the National Dengue Prevention and Control Program in district and provincial hospitals

5.      Plaque Reduction Neutralization Test (PRNT)

  • Gold standard to characterize and quantify circulating level of anti-DENV neutralizing antibody (NAb)
  • Available only at the dengue national reference laboratory

6.      Other tests:

-Total While Blood Cell (WBC) count

-Platelet

-Hematocrit

  • Routinely used in hospitals as standard dengue diagnostic tests
  • Look for trend of decreasing WBC, decreasing platelet and increasing hematocrit

NATIONAL DENGUE PREVENTION AND CONTROL PROGRAM

Vision                    A dengue free Philippines

 

Mission                  Ensure healthy lives and promote well-being for all at all ages

Goal                       To reduce the burden of dengue disease

Objectives/            1.) To reduce dengue morbidity by atleast 25% by 2022

Indicators               Morbidity rate = No. of suspect, probable & confirmed cases x100,000

                                                                                 total population

                                                             (baseline: 198.1 per 100,000 population)

                                                         (2015 data: 200,145/100,981,437 x 100,000)

 

                              2.) To reduce dengue mortality by atleaset 50% by 2022

                              Mortality rate = No of dengue (probable & confirmed) deaths x 100,000

                                                                                 total population

                                                              (baseline: 0.59 per 100,000 population)

                                                             (2015 data: 598/100,981.437 x 100,100)

 

                              3.) To maintain Case Fatality Rate (CFR) to < 1% every year.

                                                CFR = no. of dengue (probable & confirmed) deaths x 100

                                                                   no. of probable & confirmed cases

 

PROGRAM COMPONENTS

  1. Surveillance
  • Case Surveillance through Philippine Integrated Disease Surveillance and Response (PIDSR)
  • Laboratory-based surveillance/ virus surveillance through Research Institute for Tropical Medicine (RITM) Department of Virology, as national reference laboratory, and sub-national reference laboratories.
  • Vector Surveillance through DOH Regional Offices and RITM Department of Entomology

   2. Case Management and Diagnosis

  • Dengue Clinical Management Guidelines training for hospitals.
  • Dengue NS1 RDT as forefont diagnosis at the h ealth center/ RHU level.
  • PCR as dengue confirmatory test available at the sub-national and national reference laboratories.
  • NAAT-LAMP as one of confirmatory tests will be available at district hospitals, provincial hospitals and DOH retained hospitals.

   3. Integrated Vector Management (IVM)

  • Training on Vector Management, Training on Basic Entomology for Sanitary Inspector, Training on Integrated Vector Management (IVM) for health workers.
  • Insecticide Treated Screens (ITS) as dengue control strategy in schools.

   4. Outbreak Response

  • Continuous DOH augmentation of insectides such as adulticides and larvicides to LGUs for outbreak response.

   5. Health Promotion and Advocacy

  • Celebration of ASEAN Dengue Day every June 15
  • Quad media advertisement
  • IEC materials

   6. Research

   

STRATEGIES

  • Enhanced 4S Strategy

S - earch and Destroy

S - eek Early Consultation

S - elf Protection Measures

S - ay yes to fogging only during outbreaks

 

LINKS TO PROGRAM POLICIES AND GUIDELINES

 

AO 2016-0043                                                                                     Guidelines for the nationwide Implementation of Dengue Rapid Diagnostic Test
AO 2012-006                                                                   Revised Dengue Clinical Management Guidelines
AO 2001-0045                  Guidelines on the Application of Larvicides on the Breeding Sites of Dengue Vector Mosquitoes in Domestic Water
DM 2017-0353Implementation Guidelines for Initial Implementation of Nucleic Acid Amplification Assay - Loop Mediated Isothermal Assay (LAMP) as One of Dengue Confirmatory Tests to Support Dengue NSI RDT
DM 2015-0309Reactivation of Dengue Fast Lanes and Continuing Improvement of Systems for Dengue Case Management and Services
DM 2014-0112Technical Guidelines, Standards and other Instructions for Reference in the Implementation of Sentinel-based Active Dengue Surveillance