Burn Down the Sky by James Jaros

Wicca raped the minds of men and women alike, bludgening them with psychosis, shattering halucinations too wrenching to endure. No one counted the victims, no one could, but billions were said to have slain themselves. Off bridges, towers, with acid cocktails and tire irons, mass incineration and poison chambers. A holocaust of willing horrors, of mad oaths for ending life. Waves of suicide so thick they'd left cities roasting with mouldering flesh, the reeky heat of rot and waste rising from the streets choking with corpses and the creatures that scavenged them - raptors, ravens and vultures that darkened skylines and shadowed the dead, and rats and cats and carrion dogs grown huge as hogs.