The outbreak of West Nile in North America in 2002, which affected more than forty states in the United States, has led Public Health Agencies to adress the risk of emergence of vectorial zoonosis, outside of the area tropical. This epidemic events associated with climate change, has highlighted the central role of migratory birds in spreading the virus. The biology of birds, especially the migratory phenomenon, ensures a transport of viruses over long distances and across very diverse species. The Middle East, located at the crossroad between different continents, is extremely prone to the spread of zoonotic diseases, like West-Nile, in the Northern countries. The circulation of WN virus has reported from different countries in the region; such as Egypt, Israel, Lebanon, Iraq, United Arab Emirates and Iran. Saidi et al. (1970) have established the presence of antibodies to West Nile among the population of the Caspian coast (northern Iran), the provinces of Khorasan (Northeast) and Khuzestan (Southwest). Our study, in the framework of a collaborative programme associating TIMC-IMAG UMR CNRS UJF VetAgroSup, International Network of Institut Pasteur and Centre National d'Etudes Spatiales, aim to: (i) characterizing the circulation of the virus from West Nile in the equine population of Iran, and (ii) and modelling the health impact of the environment and climate on the transmission. The results obtained allow us to assess the risk associated with spatial and temporal spread of the virus by migratory birds. Particular attention is given to the study of environmental and climatic determinants that may increase the potential for transmission.
