West Nile virus is a member of the Flaviviridae family, an arbovirus responsible for an emerging disease of significance in both animal health and public health, as it is considered a zoonotic disease. It is phylogenetically related to the Japanese encephalitis complex and was first isolated in 1937. Between 1999 and 2010, it spread to humans and equines in the United States, demonstrating that the importation and establishment of vector-borne pathogens represent a serious public health threat. In humans, clinical manifestations range from a subclinical infection to death. The natural cycle of this disease involves wild and domestic birds as natural reservoirs, facilitating widespread virus dissemination and perpetuating the enzootic cycle. Common mosquito genera have been identified as primary vectors, capable of maintaining the virus within the natural mosquito-bird-mosquito transmission cycle. The fever and encephalitis caused by this virus can have serious health consequences. Due to its epidemiological characteristics, it is included in World Health Organization’s International Health Regulations and is classified as a notifiable disease by the WOAH.