Summary
Dengue is a viral disease transmitted by mosquitoes (especially Aedes aegypti) and is widely distributed throughout the tropics and subtropics. Dengue classically presents with high fever, headache, body aches, exanthem, and generalized lymphadenopathy. Symptoms usually subside within one week. Some cases progress to the more severe dengue hemorrhagic fever (DHF) with thrombocytopenia, spontaneous bleeding, and potentially shock (dengue shock syndrome). Treatment is supportive. A vaccination is available for use in children, living in endemic areas, with confirmed prior dengue virus infection.
Epidemiology
- Distribution: tropical regions; worldwide, particularly Asia (e.g., Thailand)
-
Incidence
- Most common viral disease affecting tourists in tropical regions
- ∼ 400 million infections per year worldwide
References:[1]
Epidemiological data refers to the US, unless otherwise specified.
Etiology
-
Pathogen
- Dengue virus (Serotype: DENV 1–4)
- RNA virus of the genus Flavivirus
-
Transmission route [2]
- Vector-borne; : mosquitoes most commonly from the species Aedes aegypti
References:[3]
Clinical features
| Clinical featues of Dengue fever | |||
|---|---|---|---|
| Course | Clinical features | ||
| Dengue fever | Dengue without warning signs [3][4] |
|
|
| Dengue with warning signs [3][4] | |||
| Severe dengue (Formally called dengue hemorrhagic fever or DHF) [3][4] |
|
| |
| Dengue shock syndrome (DSS) |
|
| |
If symptoms appear more than 2 weeks after returning from a dengue-endemic region, it is very unlikely that dengue is the cause.
Severe dengue is more frequent in individuals who experience a repeat infection with a second serotype, especially serotype 2.
Diagnostics
Laboratory tests
- Leukopenia
- Neutropenia
- Thrombocytopenia
- ↑ AST
- Hct significantly increased or decreased in DHF (due to plasma leakage)
Confirmation of diagnosis [6]
Acute phase (≤ 7 days after symptom onset)
- Serologic tests: MAC-ELISA to detect IgM
- Molecular Tests (NAAT) to detect viral RNA
- NS1 antigen test: detection of the Dengue NS1 antigen (Dengue non-structural protein 1) via ELISA [7]
- Tissue tests (IHC)
Convalescent phase (i.e., > 7 days after symptom onset)
- Serologic tests (IgM, IgG)
- Molecular Tests (NAAT)
- Tissue tests (IHC)
Differential diagnoses
Chikungunya fever [8][9]
- Epidemiology: mainly occurs in the tropical and subtropical regions
-
Etiology
- Pathogen: Chikungunya virus (belongs to the alphavirus genus of the family Togaviridae)
- Transmission route: mosquitoes (Aedes aegypti and Aedes albopictus), possibly leading to coinfection with dengue
-
Clinical features
- Incubation period: usually 3–7 days
- Fever, malaise
- Headache
- Lymphadenopathy
- Severe bilateral polyarthralgia
- Periarticular edema
- Maculopapular rash
- Diagnosis
- Treatment: supportive
-
Complication: chronic arthritis
- Most common and severe complication
- May last for months to years and lead to long-term disability
- Prognosis: Most individuals fully recover within a week.
Severe hemorrhagic manifestations with shock and death as well as decreased neutrophil and platelet counts are more indicative of Dengue fever than Chikungunya fever.
Other
The differential diagnoses listed here are not exhaustive.
Treatment
-
Symptomatic treatment
- Fluid administration to avoid dehydration
- Acetaminophen
-
Dengue with warning signs and severe dengue
- Blood transfusions in case of significant internal bleeding (e.g., epistaxis, gastrointestinal bleeding, or menorrhagia)
- Urgent rescucitation with IV fluids
Prevention
- Avoid exposure, use of mosquito repellent (see also → mosquito bite prevention)
- A tetravalent attenuated live vaccine (CYD-TDV)
- Recombinant yellow fever virus in which genetic material coding for the Dengue virus envelope and premembrane proteins has been inserted
- Has been approved for use in children between 9–16 years of age who live in endemic areas and have a laboratory confirmed prior dengue virus infection.
References:[10][11][12][13][14]