Clinical Illness
The fervor and ravenous nature that the media has taken with West Nile Virus, has created a much more anxious society in regard to this pathogen. Now while this virus is still potentially quite dangerous, the extent to which it has statistically affected human populations should bring a sense of relief to anyone nervous about contracting the disease. The CDC and other academic sources have seen the following trends in symptoms for this virus:

No Symptoms in Most People. Approximately 80% of people who are infected with West Nile Virus will not show any symptoms at all and will likely never know they are infected. Mild Symptoms in Some People. Up to 20% of the people who become infected will display mild symptoms known as West Nile Fever. This fever is very flu like in nature including fever, headache, and body aches, nausea, vomiting, and sometimes swollen lymph glands or a skin rash on the chest, stomach and back. Symptoms typically only last 3-6 days with no permanent effects.

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Serious Symptoms in a Few People.
About one in 150 people (.67%) infected with WNV will develop severe illness, which can include encephalitis, meningitis, and acute flaccid paralysis. The symptoms of these more serious conditions can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. These symptoms may last several weeks, and neurological effects may be permanent. The death rate for West Nile Fever following hospitalization is between 4% and 18%, 9% for those who contract Meningoencephalitis. The most important factor in determining the risks of this pathogen is that of age. In cases involving people over the age of 70 the death rates jump to nearly 21% of the individuals hospitalized by the virus.

Pathogenesis
Virus replication first occurs in skin tissues and lymph nodes, and then spreads to the Reticuloendothelial system which consisting of all the cells able to ingest bacteria or colloidal particles etc, except for certain white blood cells. A second spread of the virus can spread it to other organs and the nervous system. Blood tests can identify the virus before the onset of symptoms, but after the illness occurs, the virus is soon difficult to identify after IgM, IgG and neutralizing antibodies develop. Age fatality due to the virus has been suggested due to changes in the blood-brain barrier, the virus spreading to the brain and causing neurological problems.

Diagnosis
Diagnosis of WNV is made using serologic methods, detection of the IgM antibody in serum or CSF samples using IgM antibody capture emzyme-linked immunosorbent assay. Presence in the CSF, the Cerebrospinal fluid, reveals the Central Nervous System is infect because the antibody does not cross the blood-brain barrier.

Treatment
There is no cure for West Nile Virus, treatment is supportive, and no control studies have been taken to determine the relative success of ribavirin, interferon, gamma globulin, steroids, anti-seizure medications or osmotic agents. Infection is prevented by insect (mosquito) repellant.