The health care company dropped after a new deal with Humana Inc. changed the terms of how Amedisys would be reimbursed. Humana now will pay Amedisys on a per-visit basis, rather than an “episodic” basis. The previous deal had given Amedisys about $65 million to $70 million annually. The new deal will cut that in half beginning this quarter, Amedisys said.