Published: Aug 29, 2011 11:07 AM EDT
Updated: Aug 29, 2011 3:03 PM EDT


ROME (AP) - The United Nations has warned of a possible resurgence of the deadly bird flu virus and has urged greater surveillance.
 
The U.N. Food and Agriculture Agency says a mutant strain of H5N1 avian influenza, which can apparently sidestep defenses of existing vaccines, is spreading in China and Vietnam.
 
Last week, the U.N. reported that a 6-year-old Cambodian girl had died from bird flu, the eighth person to die from H5N1 this year in Cambodia.
 
FAO says bird migrations over the past two years have brought H5N1 to countries that had been virus-free for several years, including Israel, the Palestinian territories, Bulgaria, Romania, Nepal and Mongolia.
 
Globally there have been 331 human deaths from 565 confirmed bird flu cases since 2003.