West Nile fever is a reemerging mosquito-borne viral disease in Europe, caused by the West Nile virus (WNV), which belongs to the Flavivirus genus. The virus has been isolated in various regions across Africa, Asia, and Europe, with outbreaks occurring in countries such as Romania, Italy, and the Czech Republic. The 1996-97 outbreak in Romania was the largest arboviral illness in Europe since the 1980s. WNV is transmitted primarily by mosquitoes, particularly Culex species, and can cause febrile, sometimes fatal, illnesses in humans and animals. Wild birds are the main hosts, and migratory birds play a key role in spreading the virus to temperate regions. Other vertebrates, including horses, can also be infected, with horses being particularly susceptible to severe disease. The virus can persist in various hosts and may be transmitted through ticks in certain conditions. In Europe, the virus is mainly transmitted through rural and urban cycles, with the urban cycle dominating in the 1996-97 outbreak in Romania. The disease is influenced by environmental factors, including climate and human activities, which can increase mosquito populations and the risk of outbreaks. Surveillance is essential for monitoring the spread of WNV, and research is ongoing to understand its persistence and transmission mechanisms. Global warming may increase the distribution and abundance of mosquito vectors, potentially leading to more frequent outbreaks. The study highlights the importance of continued research and surveillance to manage the reemergence of WNV in Europe.West Nile fever is a reemerging mosquito-borne viral disease in Europe, caused by the West Nile virus (WNV), which belongs to the Flavivirus genus. The virus has been isolated in various regions across Africa, Asia, and Europe, with outbreaks occurring in countries such as Romania, Italy, and the Czech Republic. The 1996-97 outbreak in Romania was the largest arboviral illness in Europe since the 1980s. WNV is transmitted primarily by mosquitoes, particularly Culex species, and can cause febrile, sometimes fatal, illnesses in humans and animals. Wild birds are the main hosts, and migratory birds play a key role in spreading the virus to temperate regions. Other vertebrates, including horses, can also be infected, with horses being particularly susceptible to severe disease. The virus can persist in various hosts and may be transmitted through ticks in certain conditions. In Europe, the virus is mainly transmitted through rural and urban cycles, with the urban cycle dominating in the 1996-97 outbreak in Romania. The disease is influenced by environmental factors, including climate and human activities, which can increase mosquito populations and the risk of outbreaks. Surveillance is essential for monitoring the spread of WNV, and research is ongoing to understand its persistence and transmission mechanisms. Global warming may increase the distribution and abundance of mosquito vectors, potentially leading to more frequent outbreaks. The study highlights the importance of continued research and surveillance to manage the reemergence of WNV in Europe.