West Nile Fever (WNF) is caused by a B arbovirus, which was first isolated in 1937 in Uganda. In Israel the disease bears an epidemic character, and during 1950-1957 several widespread outbreaks of WNF were described in detail. It emerged from obscurity in 1999 when the first incursion of the virus in North America caused 62 cases of encephalitis and 7 deaths in New York. In 1996 an outbreak in Romania signaled that WNF had emerged as clinically important disease in Europe. The virus is transmitted by a mosquito vector. Wild birds serve as amplifying hosts. Human and some domestic animals such as horses, can be infected incidentally. While neurological disease has been prominent in some epidemics, the West Nile virus infection is usually asymptomatic in areas of the world where the virus is endemic. This is a case study of the first patient diagnosed and treated for West Nile Fever in the Western Galilee, Israel. The epidemiology, pathogenesis, clinical manifestations, diagnosis and treatment of the disease are presented in detail.