Dengue Fever

Basics

Dengue fever occurs secondary to dengue viral infection
Most prevalent mosquito-borne viral infection
Poorly understood immunopathologic response causes dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS)
DHF and DSS usually occur in patients with previous exposure to dengue virus
Hemorrhagic manifestations occur after defervescence of fever
Vascular permeability increases
Plasma extravasates into extravascular space, including pleural and abdominal cavities
Dengue fever, DHF, and DSS
World Health Organization – required criteria for the diagnosis of DHF:
- Fever
- Bleeding evidenced by one of the following: Positive tourniquet test, petechiae, ecchymosis, purpura, GI tract bleeding, injection site bleeding
- Increased vascular permeability and plasma leakage as evidenced by an elevated hematocrit (>20%), decreased hematocrit >20% after volume replacement or pleural effusions, ascites or hypoproteinemia
- Thrombocytopenia (<100,000/mm³)
World Health Organization – required criteria for diagnosis of DSS:
- All 4 criteria of DHF +
- Rapid and weak pulse
- Narrow pulse pressure or hypotension for age
- Cold, clammy skin
- Restlessness
A vaccine is under development

Occurs in tropical and subtropical regions: Asia, Africa, Central and South America, and the Caribbean
Caused by dengue virus serotypes 1–4. A fifth serotype was identified in 2013
Transmitted by mosquitoes: Aedes aegypti and Aedes albopictus
Incubation period of 3–14 d
There is only transient and poor cross protection among the 4 serotypes
Up to 390 million infections occur per year with nearly 100 million resulting in illness

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