The suicide collectors

"The Despair has plagued the earth for five years. Most of the world's population has inexplicably died by its own hand, and the few survivors struggle to remain alive. A mysterious, shadowy group called the Collectors has emerged, inevitably appearing to remove the bodies of the dead. But in the crumbling state of Florida, a man named Norman takes an unprecedented stand against the Collectors, propelling him on a journey across North America. It's rumored a scientist in Seattle is working on a cure for the Despair, but in a world ruled by death, it won't be easy to get there."@en
"The despair has plagued the earth for five years. Most of the world's population has inexplicably died by its own hand, and the few survivors struggle to remain alive. A mysterious, shadowy group called the Collectors has emerged, inevitably appearing to remove the bodies of the dead. But in the crumbling state of Florida, a man named Norman takes an unprecedented stand against the Collectors, propelling him on a journey across North America. It's rumoured a scientist in Seattle is working on a cure for the Despair, but in a world ruled by death, it won't be easy to get there. -- Publisher description."
"In the wake of a mysterious plague that has caused ninety percent of the world's population to commit suicide, survivor Norman journeys across the remains of North America to counter a shadowy group and locate a scientist who is rumored to be working on a cure."