Pete Doherty has undergone "immediate treatment" after developing a high fever and shortness of breath.The Libertines, who married Katia de Vidas in a secret wedding ceremony in September last year, was forced to cancel a string of his UK shows after his health worsened on Thursday night. In a post shared to his Instagram account, it was revealed that the doctor was quickly called in, and the 42 year old was diagnosed with a respiratory infection.