DISEASE FILE · GRADE C: WHO/CDC, CHECKED 2026-09
West Nile: the red flags are neurological.
About 1 in 5 infected people get fever; about 1 in 150 get the dangerous form, which touches the brain and nerves. The signs to know are weakness, confusion and stiff neck.
PLATE 204
- 1 · Gloves first: never bare-hand a dead bird
- 2 · Bag, label, call: the surveillance chain starts here
Neurological red flags: emergency care
These mark neuroinvasive disease: the 1-in-150 form that hospitalizes.
WEAKNESS
Sudden limb weakness or paralysis
CONFUSION
Disorientation, altered behavior
STIFF NECK
With fever and headache
TREMORS
Uncontrolled movements, seizures
No vaccine, no specific treatment exist. Supportive care only, which is why the neurological flags matter: they change where you are treated, not what with.
Sources checked 2026-09 · How we grade
THE QUESTION PEOPLE ACTUALLY TYPE
How serious is West Nile virus? Most infections are silent; about one in five cause fever, and about one in 150 cause neuroinvasive disease with weakness, confusion or stiff neck. Those flags mean emergency care.
CDC West Nile clinical summary, checked 2026-09
The numbers, in context
Every row sourced, every page dated.
| FACT | VALUE | SOURCE |
|---|---|---|
| Silent infections | About 80% of cases | CDC |
| Fever form | About 20% | CDC |
| Neuroinvasive form | About 1 in 150 | CDC |
| Vector | Culex, night biters, organic water | CDC |
| Treatment | Supportive only; no vaccine | CDC |