Dengue

Dengue fever is a mosquito-borne disease caused by dengue virus (DENV), an RNA virus belonging to the Flaviviridae family, genus Flavivirus. The pathogen exists as four antigenically distinct serotypes (DENV-1 through DENV-4), each capable of causing the full range of dengue clinical manifestations. Infection with one serotype confers lifelong immunity to that specific type but provides only transient cross-protection against the remaining serotypes, creating immunological complexity that influences subsequent infection severity.

The incubation period between mosquito bite and symptom onset ranges from 3 to 14 days, with most cases presenting within 4 to 7 days. Approximately 80% of infections are either asymptomatic or manifest as uncomplicated fever, while roughly 5% progress to severe dengue. Characteristic symptoms of mild dengue include sudden-onset high fever, retro-orbital headache, myalgia and arthralgia (often called 'breakbone fever'), nausea, vomiting, and a characteristic maculopapular rash with pruritus. The clinical course progresses through three phases: a febrile phase lasting 2 to 7 days, a critical phase of approximately 24 to 48 hours during which plasma leakage may occur, and a recovery phase. Severe dengue (formerly dengue hemorrhagic fever or dengue shock syndrome) presents with plasma leakage leading to hypovolemic shock, significant bleeding, thrombocytopenia, and potentially organ dysfunction. Warning signs of progression to severe disease include severe abdominal pain, persistent vomiting, rapid breathing, and mucosal bleeding.

Dengue is endemic across tropical and subtropical regions worldwide, with transmission exhibiting strong seasonal patterns that typically peak during and after rainy seasons when mosquito vector populations flourish. Multiple factors drive epidemic intensity and geographic expansion, including high Aedes mosquito population density, population susceptibility to circulating serotypes, favorable ambient temperatures, precipitation levels, and humidity—all of which influence vector reproduction, feeding behavior, and viral incubation dynamics. Unplanned urbanization and climate change phenomena including heat waves have intensified dengue transmission in frequency, duration, and geographic distribution in recent decades. Significant surveillance and control challenges persist, including insufficient sustained monitoring systems, resource constraints, and fragmented programmatic responses across affected countries.

Dengue is primarily transmitted through the bite of infected female mosquitoes of the Aedes genus, with Aedes aegypti serving as the principal vector globally. The mosquito acquires the virus by feeding on an infected human host and subsequently can transmit it to susceptible individuals during subsequent blood meals. Human-to-human direct transmission does not occur; the mosquito vector is essential for propagation of the pathogen in nature.

Source-backed detail on specific high-risk groups is not yet available. However, the source material notes that children and older individuals face elevated risk of complications compared to other age groups, with young children typically experiencing more intense symptoms. Pregnant women who contract dengue demonstrate increased risk of adverse pregnancy outcomes including miscarriage, low birth weight, and premature birth.

Primary prevention strategies focus on vector control and personal protection against mosquito bites. Mosquito elimination through environmental management and source reduction, combined with personal protective measures such as insect repellents, insecticide-treated bed nets, and protective clothing, constitute the cornerstone of prevention. Two dengue vaccine formulations have received regulatory approval and entered commercial markets; however, Dengvaxia (the first approved vaccine, available since 2016) carries specific usage restrictions based on prior dengue exposure status due to increased severe disease risk in seronegative recipients.

Dengue surveillance should account for the disease's seasonal transmission patterns, with heightened vigilance during and following rainy periods when vector abundance peaks. The WHO's 2023 Grade 3 emergency designation reflects the escalating global burden and underscores the need for robust, integrated surveillance systems capable of detecting early warning signals of outbreak expansion. Laboratory confirmation through detection of viral RNA or serological testing remains important for accurate case classification, given symptom overlap with other febrile illnesses endemic to the same regions such as malaria, influenza, and Zika virus infection.

1. 1 WHO Health Topics. Dengue and severe dengue.
2. 2 WHO Q&A. News.
3. 3 Wikidata. Dengue virus.
4. 4 Wikipedia. Dengue fever - Wikipedia.

ICD-10

A90

ICD-11

1D2Z.0

Total cases

176K

Total deaths

15

Peak month

2014-10

Coverage

4 reporting countries · 2000-01-01 → 2023-03-25