This episode's headline: Bug Bytes; Silent Killer; Peru's Challenger; Political Wrap. ANCHOR: MARGARET WARNER; GUESTS: DAN SCHRADER, Trend Micro, Inc.; MARK RASCH, Global Integrity Corporation; JIM YOST, Ford Motor Company; DR. ED. ROCCELLA, National Heart, Lung, and Blood Institute; ALEJANDRO TOLEDO, Peruvian Presidential Candidate; MARK SHIELDS, Syndicated Columnist; PAUL GIGOT, Wall Street Journal; CORRESPONDENTS: MIKE JAMES; TERENCE SMITH; BETTY ANN BOWSER; SUSAN DENTZER; RAY SUAREZ; SPENCER MICHELS; MARGARET WARNER; FRED DE SAM LAZARO; GWEN IFILL; TERENCE SMITH; KWAME HOLMAN