A bunch of new variants of the Bagle virus and Mytob worm are spreading, but they won’t pose a major threat if people take the usual precautions, security companies say. Three new iterations of Bagle, released at one-hour intervals, popped up according to Maksym Schipka, a senior antivirus researcher at MessageLabs. About 70 variants of the mass-mailing computer virus have been reported since it first appeared in January 2004.