PDD is a fatal disease that causes nervous system disorders in both domesticated and wild birds in the psittacine, or parrot, family worldwide.

• 前胃扩张症是一种致命性的疾病，它可以造成全世界范围内的不管是驯养的还是野生的鹦鹉目或科底下的鹦鹉神经系统紊乱。