Dengue Fever

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🦟 Dengue Fever – Overview

Dengue fever is a mosquito-borne viral infection caused by the dengue virus (DENV). It is common in tropical and subtropical regions and can range from a mild illness to a potentially deadly condition known as severe dengue or dengue hemorrhagic fever.

🧬 Cause

  • Caused by Dengue virus (DENV): There are 4 serotypes (DENV-1, DENV-2, DENV-3, DENV-4)
  • Transmitted by the bite of an infected Aedes aegypti or Aedes albopictus mosquito

📍 Transmission

  • Mosquitoes get infected by biting a person with dengue virus in their blood
  • They then transmit the virus to other people
  • Not spread from person to person directly

⚠️ Symptoms

🕐 Incubation period: 4–10 days after mosquito bite

1️⃣ Classic Dengue Fever

  • Sudden high fever (up to 40°C or 104°F)
  • Severe headache
  • Pain behind the eyes
  • Muscle and joint pain (“breakbone fever”)
  • Skin rash (usually appears 3–4 days after fever starts)
  • Nausea, vomiting
  • Fatigue

2️⃣ Severe Dengue (Dengue Hemorrhagic Fever or Dengue Shock Syndrome)

  • Bleeding (nose, gums, internal)
  • Blood in vomit or stool
  • Low blood pressure, shock
  • Difficulty breathing
  • Can be life-threatening, especially in children and second-time infections

🧪 Diagnosis

  • Blood tests:
    • NS1 antigen test (early detection)
    • PCR test (to detect viral RNA)
    • IgM/IgG antibodies (after 4–5 days of symptoms)
  • CBC: May show low platelet count and elevated hematocrit

💊 Treatment

  • No specific antiviral treatment
  • Supportive care:
    • Acetaminophen (paracetamol) for fever and pain
    • Avoid aspirin and ibuprofen (can increase bleeding risk)
    • Fluids to prevent dehydration
  • Hospitalization may be needed for severe dengue

🛡️ Prevention

  • No cure, so prevention is key:
    • Use mosquito repellents
    • Wear long sleeves and pants
    • Sleep under mosquito nets
    • Remove standing water (breeding sites)
    • Use window screens or insecticide sprays

💉 Vaccine:

  • Dengvaxia is approved in some countries for people who have had a previous dengue infection
  • New vaccines like Qdenga (TAK-003) are being rolled out in certain regions

🌍 Endemic Regions

  • Southeast Asia
  • South America
  • Central America
  • Africa
  • Pacific Islands
  • Caribbean

✅ Key Facts

  • Infection with one serotype gives lifelong immunity to that type, but not to others
  • Second infections with a different serotype increase risk of severe dengue
  • Early diagnosis and proper care reduce fatality rates to below 1%
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