The illness is usually terminal.

这种病通常为不治之症。

《牛津词典》

The illness was diagnosed as cancer.

此病诊断为癌症。

《牛津词典》

The illness frequently coexists with other chronic diseases.

这种病往往与其他慢性病同时存在。

《牛津词典》

The aide recovered, but the illness was part of the worldwide outbreak of H1N1 swine flu.

VOA: standard.2009.08.10

And then you would recover for a while, that initial phase of the illness would disappear, your fever might go down, you might appear to be normal.

接着你会暂时恢复,在开始阶段出现的症状会消失,你的体温会降下来,看起来似乎比较健康

耶鲁公开课 - 生物医学工程探索课程节选

If we don't have these things,that's when the illness comes in.

如果不具备这些，疾病就会趁虚而入。

哈佛公开课 - 幸福课课程节选

The transplant is used to get the patient past the critical stage of the illness.

BBC: Some liver transplants 'avoidable'

Since the outbreak began in November, 77 people have needed hospital treatment for the illness.

BBC: South West Wales

But Amanda has not let the illness stop her doing what she wants to do.

BBC: 'I'm lucky to have survived pancreatic cancer'