Dengue Virus

Family:

Genome:

• The Family includes:

  Kunjin
  Dengue
  Japanese encephalitis virus
  Murray valley encephalitis virus
  St. Louis encephalitis virus
  Louping ill virus
  Yellow fever virus
  Chikungunya ("doubled-up")
  Omsk virus
  
• There are four serotypes of dengue
• Dengue uses the mosquito Aëdes aegypti as its principle vector

  Infection and Replication:

  • Dengue's infection of monocytes (and possibly vascular endothelium) induces the release of cytokines that can lead to complications including shock.

  Pathology:

  Syndromes
  • Minor febrile illness after a 4-8 day incubation. Aches and arthralgia which can progress to arthritis, myositis and a maculopapular rash (also called breakbone fever or dandy fever)
  • The most serious syndrome includes bleeding into the skin and mucous membranes following fever. Rash and haemorrhaging from body orifices is accompanied by a drop in the platelet numbers (thrombocytopaenia) and sometimes disseminated intravascular coagulation (DIC).
  • In children, Dengue Haemorrhagic Shock Syndrome (DHSS) is a dangerous complication in which fever is followed by collapse with shock, decreased blood pressure, and signs of haemorrhage as described above.
  • DHSS results from immune enhancement following infection with a different serotype from that which caused a previous infection.
  • Tretament is symptomatic - recovering fluid loss, returning electrolyte levels to normal and transfusing if blood loss is severe.