It has been clearly established, from many years of research, that wild birds are the hosts of low pathogenic avian influenza (LPAI) viruses. LPAI viruses have been isolated from 105 wild birds species (26 bird families) with Anseriformes (ducks, swans and geese) and Charadriiformes (gulls, terns and waders) constituting the major natural reservoirs. These viruses are distributed globally and in generally reside in long-distance migratory species. Most importantly, wild birds that serve as reservoirs of LPAI viruses do not show signs of illness or disease. A relationship exists in which the virus survives, replicates, and is transmitted to other wild bird hosts. Wild birds are essentially unaffected by hosting these viruses.
In 2004, the EMPRES program supported a small scale HPAI surveillance effort in wild birds in Mongolia through the Wildlife Conservation Society. In 2005, following the spread of HPAI to Russia , Kazakhstan and Central Europe , FAO promoted a large scale HPAI surveillance programme in wild birds to track the evolution and possible spread of the virus along migratory routes. These activities were initiated through Technical Cooperation Programs. A first campaign of surveillance, conducted in 14 countries between mid-January and mid-May 2006, was coordinated by FAO and implemented by CIRAD in collaboration with Wetlands International. Implementation of the field operations were organized in partnership with national wildlife and veterinary services and in collaboration with international conservation and research organizations such as the African Bird Ringing Unit (AFRING), Oiseaux Migrateurs du Paléarctique Occidental (OMPO), Office National de la Chasse et de la Faune Sauvage (ONCFS), De Vereniging SOVON Vogelonderzoek Nederland , Wildfowl and Wetlands Trust, UK (WWT), local ornithological non-governmental organizations NGOs, national hunting associations and safari operators. Geographical distributions of sampling sites as well as sampling periods were selected to cover the seasonal patterns of waterbird migration over Eastern Europe , the Middle East and Africa , and targeted natural sites where waterbirds of various geographical origins congregate and mix.
A second round of surveillance was carried out from September 2006 to April 2007 in a total of 19 countries; Burkina Faso, Chad, Egypt, Ethiopia, Iran, Malawi, Mali, Mauritania, Morocco, Kenya, Niger, Nigeria, Romania, Senegal, Sudan, Tunisia, Turkey, Ukraine and Zambia. A total of approximately 18,000 samples have been collected and while some analyses are still underway, no positive samples for H5N1 HPAI have been found in at least 10,000 samples from healthy, wild free-ranging birds, though other AI viruses have.