Going Bovine by Linda Bray

Sixteen year old Cameron has spent his entire life flying under the radar. Your typical high school slacker, he spends most of his time getting high in the school's bathroom or visiting the local music store. When he's diagnosed with the deadly Mad Cow Disease, he finds himself on a crazy journey to find the one scientist in the world who may hold the cure. Accompanied by his new friend Gonzo (an extreme hypochondriac) and the flighty angel Dulcie, he embarks on what may be his first and only wild adventure.