Last reviewed: September 2018
Last updated: May  2017



History and exam

Key diagnostic factors

  • fever of sudden onset
  • malaise
  • myalgia
  • arthralgia
  • pharyngitis
  • anorexia
  • abdominal pain
  • visual disturbances
  • headache
  • rash
  • lymphadenopathy
  • conjunctival injection
  • multifocal chorioretinal lesions
  • chorioretinitis and inflammatory vitritis
  • seizures
  • respiratory distress
  • jaundice
  • epigastric tenderness
  • mild confusion
  • disorientation
  • stupor/coma
  • neck stiffness
  • Kernig sign
  • Brudzinski sign
  • muscle paralysis
  • parkinsonism
  • ataxia
  • myoclonus
  • tremors

Other diagnostic factors

  • nausea/vomiting
  • generalized muscle weakness
  • splenomegaly
  • retinal hemorrhages
  • chest pain, dyspnea, palpitations
  • photophobia
  • depression
  • loss of memory
  • bowel and bladder dysfunction
  • cranial nerve palsies

Risk factors

  • significant vegetation
  • exposed skin while outdoors
  • stagnant water
  • blood transfusion
  • needlestick injuries
  • organ transplant
  • living in/visiting areas with high WNV activity
  • late spring/early fall
  • outdoor activities between dusk and dawn

Diagnostic investigations

1st investigations to order

  • CSF WNV-specific IgM using MAC-ELISA
  • serum WNV-specific IgM using MAC-ELISA
  • CSF protein
  • CSF cell count
  • CSF glucose
  • CBC
  • serum electrolytes
  • LFTs
  • serum amylase/lipase
  • CT head
Full details

Investigations to consider

  • serum or CSF WNV-specific IgM using plaque-reduction neutralization test (PRNT)
  • WNV isolation from serum, CSF, or body tissue using culture or PCR
  • MRI brain
Full details

Treatment algorithm


Authors VIEW ALL

Bruce Y. Lee

Associate Professor of International Health


Global Obesity Prevention Center

Director of Operations Research

International Vaccine Access Center (IVAC)

Johns Hopkins School of Public Health




BYL declares that he has no competing interests.

Peer reviewers VIEW ALL

Executive Scientific Officer

American Red Cross




SS declares that she has no competing interests.

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