Doctor Alexander Tiendrebeogo from the World Health Organization says the disease causes no pain at first.

VOA: special.2009.04.06

And the pain that he causes is intrinsically bad.

他造成的痛苦本质是坏的。

耶鲁公开课 - 死亡课程节选

Such a headache causes severe pain that goes away but returns later.

VOA: special.2010.03.30

The hepatitis A virus causes high body temperature,pain and weakness.

VOA: special.2010.11.16