West Nile disease (WN) is a notifiable non-contagious infectious disease caused by a flavivirus. In the last years it has become especially relevant in Europe because of its reemergence, particularly in the countries of the Mediterranean basin. This disease is vectorial, involving mainly mosquitoes of the genus Culex, and affects a wide range of hosts, especially birds (considered to be amplifying hosts), equines and humans (both considered to be dead-end hosts). In equines, this virus is usually associated with a subclinical infection, although a small percentage may suffer from neurological symptoms, or even a severe encephalomielitis leading to the death of animals. In Spain, the virus started to cause outbreaks in 2010 in several farms in southern Andalusia; in 2011 the number of cases increased. Furthermore, a lineage distinct (lineage 2) from the one currently circulating in our country (lineage 1) has been spreading from eastern Europe, causing outbreaks of higher virulence affecting a large number of birds, horses and even humans. Global warming is having a direct influence on the distribution and survival of vectors, which leads to enhance surveillance and control measures against this disease that is exacerbating each new season.
This section contains all information relevant to the epidemiology of WN and its background, current situation and outbreak updates, which will be periodically reviewed by sending new communications. For more information, please consult the West Nile simulation on our website.