1. 疾病;(动植物的)病害
A disease is an illness which affects people, animals, or plants, for example one which is caused by bacteria or infection.
e.g. ...the rapid spread of disease in the area.
疾病在这一区域的迅速蔓延
e.g. ...illnesses such as heart disease...
诸如心脏病之类的疾病
2. （尤指社会某一群体的）弊病，积习，恶习
You can refer to a bad attitude or habit, usually one that a group of people have, as a disease.
e.g. ...the wretched disease of racism eating away at the core of our society.
侵蚀着我们社会核心的种族主义恶疾