 Scully discovers that two worms put together will kill each other . When the investigators place one of the worms into the infected dog , it recovers . Against Scully 's objections , Hodge and DaSilva try to place the other worm into Mulder and Hodge realizes that DaSilva is the infected person . He and Mulder restrain the hysterical DaSilva and place the last worm inside her . When they are rescued , DaSilva is quarantined and the others are released . Although Mulder wants to return to the site , he is told that it has been destroyed by the government . 
