United Nations Food and Agricultural Organization (FAO) urged heightened preparedness and surveillance amid signs that a mutant strain of the deadly bird flu virus is spreading.

The H1N1 Avian Influenza virus was eliminated, infected rate peaked in 2006 the remaining nations with endemic outbreak has risen since then to almost 800 cases recorded between 2010-2011

Juan Lubroth the agency's chief veterinary office said that migrations have helped the virus travel over long distances and expand geographically. The H5H1 virus has shown up in poultry or wild birds in countries that had been virus-free for several years.

The H5N1 virus has been found in Nepal, Mongolia, Israel and Palestinian territories, Bulgaria and Romania.

Another concern for FAO is that the virus variant in China and Vietnam is able to bypass the defenses provided by existing vaccines.

The new virus strain H5N1 - has put Vietnam's veterinary services on high alert and reportedly considering targeted campaign this fall. The virus circulation in Vietnam poses a direct threat to rest of SE Asia as well as the Korean Peninsula and Japan. Wild bird migration can also cause the spread of the virus to other countries.

"Preparedness and surveillance remain essential" said Lubroth "This is no time for complacency. No one can let their guard down with H5N1."

Researchers point out that poultry production and marketing will determine how the disease will spread.

FAO reports that H5N1 virus has killed or forced the culling of more than 400 million domestic poultry and caused an estimated $20 billion of economic damages across the globe. It has infected and killed 331 people- 8 people died early this month in Cambodia.