疫情日益严重的英文表达可以是"the epidemic situation is becoming increasingly serious"或"the epidemic is worsening".这种表达方式源于"epidemic"一词指的是传染病，"worsen"一词指的是恶化，因此将这两个词结合起来形成了"the epidemic is worsening"这样的表达方式。
下面是一些例句：
The epidemic situation is becoming increasingly serious, and we must take immediate action to contain it.
The epidemic is worsening, and we must do everything we can to prevent it from spreading further.
We must take decisive action to stop the epidemic from worsening.
中文翻译如下：
疫情日益严重，我们必须立即采取行动控制它。
疫情在恶化，我们必须尽一切所能阻止它的扩散。
我们必须采取果断行动阻止疫情的恶化。