Reuters reports tests done in Britain to determine the extent of avian flu after the H5N1 virus was found in a dead swan may have been flawed, a science magazine said on Tuesday.http://today.reuters.com/news/articlenews.aspx?type=scienceNews&storyid=2006-04-11T180405Z_01_L11119995_RTRUKOC_0_US-BIRDFLU-BRITAIN.xml