West Nile Virus Disease

The West Nile virus disease is caused by a zoonosis present in France since the 1960s whose distribution across the planet has recently changed.

West Nile virus disease agent

The disease is caused from infection by the West Nile virus (WNV). The usual reservoir for the virus is birds which act as the amplifying host.

Transmission of West Nile virus disease

WNV affects human beings accidentally, usually from a bite from an infected mosquito although the infection may be transmitted in certain human blood products.

Symptoms of West Nile Virus Disease

The incubation period is 2 to 15 days (21 days for transfusion infections). Infection is usually clinically silent: 80% of human WNV infections are asymptomatic. In other cases the patients present a flu-like syndrome with fever, headaches, and muscle aches. Very rarely (1 in 150 cases), the disease presents a severe form with neurological features (aseptic meningitis, meningo-encephalitis, acute flaccid paralysis), and is mostly described in the elderly. The mortality rate has been estimated at 2%.

Treatment of West Nile Virus disease

There are no treatments or vaccines for the West Nile Virus disease. The medicines used only reduce symptoms.