Murray Valley encephalitis (MVE)

see also:

• zoonoses
• viruses
• Japanese encephalitis virus (JEV)
• Ross River virus (RRV)
• Barmah Forest virus (BFV)
• https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/murray-valley-encephalitis

• a flavivirus related to Japanese encephalitis virus (JEV) and dengue fever transmitted by female mosquitoes mainly along the Murray River region in Australia but it is native to northern Australia
• there is no person to person transmission

• Culex annulirostris (the common banded mosquito) is the most important mosquito species that carries this virus.
  • This mosquito also can carry Ross River virus (RRV), Barmah Forest virus (BFV), Japanese encephalitis virus (JEV)
  • breeds in fresh water and is most active at dusk and dawn

Culex annulirostris image courtesy https://wrbu.si.edu/vectorspecies/mosquitoes/annulirostris

• water birds such as herons or egrets
• chickens

• usually 7-12 days but can be 5-28 days

• most have a subclinical infection
• some have a mild illness:
  • fever
  • nausea / vomiting
  • myalgias
  • headaches
• a minority develop encephalitis which may be fatal or leave long term brain damage and which may cause:
  • severe headaches
  • neck stiffness
  • photophobia
  • seizures (especially in young children)
  • drowsiness
  • confusion
  • coma
• the acute phase of the illness lasts around 1 or 2 weeks, and the symptoms either disappear quickly or subside slowly over a period of time

• CT brain and lumbar puncture mainly to exclude other causes
• serology

• supportive care