Can west nile virus be fatal?

Yes: It's more dangerous for the young and old with weaker immune systems, and it's not common, but it is certainly possible.

Most are safe: About 80% of people bit by a mosquito infected with the west nile virus do not get sick, according to the cdc. About 20% will have relatively mild symptoms, such as fever, headache and vomiting. Symptoms can last for as short as a few days or as long as a few weeks. About one in 150 people infected with west nile will develop a severe illness, which can include paralysis, coma or death.

Yes: About 1% have severe illness which can include neurologic problems. Possible sx’s include: seizures, severe headache w stiffness of the neck, high fever, confusion & weakness. 3 to 15% of persons with severe illness die. Severe illness can include problems like encephalitis, meningitis or complete flaccid paralysis. People older than 75 are at a high risk.