West Nile virus (WNV) is a mosquito-borne zoonotic arbovirus belonging to the genus Flavivirus in the family Flaviviridae. The virus is found in temperate and tropical regions worldwide, but first identified in the West Nile sub-region in the
East African nation of Uganda in 1937. Prior to the mid-1990s WNV infection was sporadically and considered a minor risk for humans, until an outbreak in Algeria in 1994, with cases of WNV-caused encephalitis, and the first large outbreak in
Romania in 1996, with a high number of cases with neuroinvasive disease. WNV has now spread globally to Europe beyond the Mediterranean Basin and the United States, is now considered to be an endemic pathogen in worldwide especially in Africa The WNV transmission is mainly by various mosquitoes species, also ticks were incriminated The birds especially passerines are the most commonly infected animal and serving as the prime reservoir host In Egypt more than 110 mosquito species and subspecies and more than 32 genera of ticks were identified. Besides, not less than 150 species of migratory birds visit Egypt annually in addition to 350 resident ones. This review provided an overview of the current understanding flaviviruses mainly WNFV. Primary care physician and senior nurse should be able to include the disaster diseases in differential diagnosis of various clinical conditions. They should take a thorough history to request specific dependable laboratory test(s) as soon as possible, and positive patient should be transferred to the fever hospital.