Dengue infection is caused by the dengue virus that belongs to the family Flaviviridae.
There are 4 serotypes (DEN-1, DEN-2, DEN-3, DEN-4). Each serotype provides specific lifetime protective immunity against reinfection of the same serotype, but only temporary (within 2-3 months of the primary infection) and partial protection against other serotypes.
It is transmitted to humans through the bites of infected Aedes mosquitoes. It is primarily transmitted by female Aedes aegypti, a tropical and subtropical species. Humans are the main host of the virus.
After 4-10 days of incubation period, illness begins immediately.


  • Patients managed at home or admitted in the hospital without warning signs should be monitored daily until they are out of the critical phase
    • Should check for temperature pattern, volume of fluid intake & losses, urine output, warning signs, signs of plasma leakage & bleeding, hematocrit, white blood cell & platelet counts
  • Patients with shock should be monitored frequently until the critical period is over
    • Vital signs & peripheral perfusion should be checked every 15-30 minutes until the patient is out of shock, then every 1-2 hours
    • An indwelling arterial line may be placed for continuous & reproducible blood pressure measurements & regular blood sampling since in shock states, estimation of blood pressure using a cuff is usually inaccurate
    • Urine output should be checked hourly until the patient is stable & then 1-2 hourly
    • Hematocrit should be monitored before & after fluid boluses until the patient is out of shock & then 4-6 hourly
      • Changes in hematocrit must be interpreted together with the hemodynamic status, clinical response to fluid therapy & acid-base balance of the patient
    • Arterial & venous blood gases, lactate, total carbon dioxide or bicarbonate should be checked every 30 minutes to 1 hour until stable, then as needed
    • Blood glucose, renal profile, liver profile, coagulation profile should be monitored before fluid resuscitation, then as required
  • In general, patients given higher fluid infusion rate should be monitored more frequently in order to avoid fluid overload while ensuring sufficient volume replacement

Signs of recovery

  • Stable vital signs
  • Normal temperature
  • No bleeding
  • Return of appetite
  • No vomiting
  • Good urine output (0.5 ml/kg/hour)
  • Stable hematocrit
  • Convalescent confluent petechial rash

Discharge criteria for hospitalized patients

  • Visible clinical improvement
  • Absence of fever for 48 hours
  • Return of appetite
  • Good urine output
  • Stable hematocrit without intravenous fluids
  • Rising trend of platelet count
  • No respiratory distress


  • Preventing or reducing the transmission of dengue virus is dependent on controlling mosquito vectors or disturbing human-vector contact
  • Vaccination against dengue viruses are currently being developed, w/ promising results

Methods of Vector Control

  • Methods to control transmission should target habitats of immature & adult stages of A aegypti in the household & places where human-vector contact occurs
    • A aegypti is one of the most efficient vectors for arboviruses because it is highly anthropophilic, bites several times before oogenesis is complete & usually stays on artificial water containers closely associated w/ human habitat & commonly indoors
    • These mosquitoes do not fly far & mostly stay w/in 100 meters from where they emerged
    • Feeds mainly during daylight hours

Environmental management

  • Aims to change the environment to decrease or prevent vector dissemination & human contact w/ the vector-pathogen
  • Controlling mosquito vectors are mainly achieved by eradicating container habitats that are favorable oviposition sites & development of aquatic stages through the following:
    • Preventing access of mosquitoes to containers or emptying & cleaning them regularly
    • Using insecticides or biological control agents to kill developing stages or adult vectors
  • To decrease human-vector contact, mosquito screens may be placed on windows or doors, or mosquito nets may be used while sleeping during daytime

Chemical control

  • Larvicides should be done as complementary to environmental management
  • Adulticides are used to target adult vectors which is applied either as surface treatments or as space treatments
    • Intended to affect mosquito densities, longevity & other transmission parameters
    • Space spraying is done only to control vectors in emergency cases to suppress or prevent an epidemic
  • Individual & household protection such as clothings are advised to minimize exposure of skin & be protected from bites of dengue vectors during their active hrs
    • Repellents that contain DEET (N, N-diethyl-3-methylbenzamide), IR3535 (3-[N-acetyl-N-butyl]-aminopropionic acid ethyl ester), or Icaridin (1- piperidinecarboxylic acid-2-(2-hydroxyethyl)-1-methylpropylester) may be applied to skin or to clothes
    • Mosquito nets that are insecticide-treated also provides good protection
    • Household insecticide aerosol products or mosquito coils may also decrease biting activity\

Biological control

  • Certain species of larvivorous fish & predatory copepods (small freshwater crustaceans) may be introduced to specific container habitats of Aedes to reduce their population
  • Avoids chemical contamination of the environment but has operational limitations & are only effective against immature stages of vector mosquitoes in the larval habitat where they were introduced


  • The first dengue vaccine developed, CYD-TDV, is being reviewed by the WHO Strategic Advisory Group of Experts (SAGE) on Immunization
    • CYD-TDV is a recombinant, live, attenuated, tetravalent dengue vaccine that may be used in individuals aged 9-45 years residing in endemic areas
    • Two phase III clinical trials showed that CYD-TDV given on a 3-dose series on a 0/6/12 months schedule has an overall efficacy rate of 56% against any of the four dengue serotypes & virologically confirmed dengue infections, w/ a good safety profile
  • Other vaccines under clinical trial evaluation include subunit, DNA & purified inactivated as well as other live-attenuated vaccines
    • Additional vaccines under preclinical study evaluation are the virus-vectored & virus like particles (VLP)-based vaccines
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