About 70 per cent to 80 per cent of infected people with WNV do not develop any symptoms. For those who do develop symptoms, they will usually appear within 2 to 15 days after infection.
Mild symptoms include:
- Headache
- Body aches
- Joint pains
- Vomiting
- Diarrhea
- Rash
Less than one per cent of people who are infected may develop meningitis or encephalitis (swelling of the brain). Ten per cent of people who develop neurologic infection die.
Severe symptoms include:
- severe headache
- high fever
- stiff neck
- nausea and/or vomiting
- trouble swallowing
- drowsiness
- confusion