That wacky CDC is up to its old, potentially fatal-virus-spreading tricks again. But instead of anthrax or dengue , this time, the Centers for Disease Control brought a deadly strain of bird flu into its revolving cast of highly contagious characters. While rushing to get to a meeting, a CDC scientist accidentally tainted a tamer strain of bird flu with a far more deadly one--and then sent it out to another unsuspecting lab. Whoops.