A bird flu strain found in Europe represents a major threat to the poultry industry in countries crossed by migrating wild birds, two intergovernmental organizations said on Monday.

Germany, the Netherlands and Britain have reported cases this month of the H5N8 highly pathogenic bird flu, which is similar to one that devastated poultry flocks in South Korea earlier this year, but has never been detected in humans.

In a joint statement, the Food and Agriculture Organization (FAO) and the World Organization for Animal Health (OIE) said the threat to poultry farmers was especially high along the Black Sea and East Atlantic migratory routes of wild birds.

Poor countries, or states facing political turmoil, like Ukraine, were particularly at risk, a spokeswoman for OIE said.

Wild birds are suspected to be the carriers of the disease, which has already lead to the culling of several hundred thousand poultry in Europe this month.

"Should poultry systems with low-biosecurity conditions become infected in countries with limited veterinary preparedness, the virus could spread through farms with devastating effects, both on vulnerable livelihoods as well as on country economies and trade," FAO and OIE said.

They said other influenza outbreaks had shown that wild birds were able to carry the virus long distances.

The two organizations called for increased surveillance efforts for early detection of the virus, more measures to prevent contact between wild birds and domestic poultry, and improved rapid response capabilities for vets.

FAO and OIE warned that although H5N8 had not been found in humans it was related to the H5N1 virus, which caused the deaths of nearly 400 people and hundreds of millions of poultry after it spread from Asia into Europe and Africa in 2005-2006.

"The new virus strain provides a stark reminder to the world that avian influenza viruses continue to evolve and emerge with potential threats to public health, food security and nutrition, to the livelihoods of vulnerable poultry farmers, as well as to trade and national economies," they said.