Description

• Dengue virus (DENV) is an arthropod-borne virus (arbovirus) that causes a febrile illness characterized by intense headache (classically retro-orbital), rash, abdominal pain, nausea, and joint pain.
• The majority of DENV infections is subclinical or asymptomatic, but some people with DENV infection develop severe dengue disease, which:
  • Manifests when the fever from the initial illness subsides
  • Is characterized by plasma leak leading to hypovolemic shock and death
  • Can be anticipated based on the presence of warning signs
• Identification of severe dengue-associated warning signs is important for determining need for additional monitoring and hydration.

Epidemiology

DENV has been reemerging over the last 50 years as a significant cause of febrile illness in tropical and subtropical areas of the world.

• Approximately 50 to 60 million symptomatic infections per year worldwide
• Estimated 300 million infections per year worldwide, including subclinical or asymptomatic infections

Risk Factors

• Travel to or residing in an area that is experiencing an outbreak of or is endemic for DENV.
• Exposure to Aedes spp. mosquitoes
• Previous DENV infection of a serotype that is different than the circulating serotype

General Prevention

• Mosquito avoidance
  • Wear clothing that maximizes skin coverage.
  • Use insect repellants such as N,N-diethyl-meta-toluamide (DEET).
• Empty open containers of standing water.

Pathophysiology

• DENV has a tropism for monocytes, macrophages, and dendritic cells.
• After invading a cell, it hijacks the cellular machinery to produce more infectious virus.
• Massive activation of the host inflammatory response is thought to lead to severe dengue disease.
• DENV nonstructural protein 1 (NS1) also directly affects vascular endothelium leading to plasma leakage.

Etiology

• DENV is transmitted by Aedes aegypti and Aedes albopictus mosquitoes.
• Aedes mosquitoes are
  • Endemic in many tropical and subtropical areas of the world
  • Highly adapted to thrive in peri-urban settings, often entering homes and laying eggs in man-made containers
  • Able to lay eggs in as little as a tablespoon of water
  • Expanding their habitat range due to global warming
• DENV is endemic in many parts of South and Southeast Asia, Central and South America, and Australia.
• Humans are only known reservoir for DENV.
• DENV can be categorized into four serotypes.
  • One or more serotypes may be circulating in an area.
  • Infection from one serotype is thought to protect against reinfection from the same (homologous) serotype but does not provide durable protection against the other (heterologous) serotypes.
  • Antibodies produced against one serotype (during primary infection) can cross-react with a heterologous serotype (during secondary infection) and increase the risk for developing severe dengue disease via a mechanism called antibody-dependent enhancement of infection.
• Single-stranded RNA virus
• DENV is a member of the Flaviviridae family of viruses that includes yellow fever virus, Japanese encephalitis virus, Zika virus, hepatitis C virus.

Commonly Associated Conditions

Other tropical and subtropical infections, including other mosquito-borne infections such as malaria or other arboviruses