Human case of avian flu detected in England as virus spreads among birds - Bird flu virus likely mutated within a Louisiana patient, CDC says - Bird flu outbreak leads to deaths of tigers at Vietnam zoo - Bird flu virus found in Los Angeles County wastewater - Dozens of zoo tigers die after contracting bird flu in southern Vietnam - 47 tigers dead in Vietnam zoos due to bird flu: state media - Live poultry markets may be source of bird flu virus in San Francisco wastewater - Bird flu found in western China as US combats cattle outbreak - Bird flu virus possibly found in a handful of wastewater sites, CDC says