@i_petersen @CathNoakes @BallouxFrancois That's not the case for many infectious diseases which are environmentally controlled, eg. food-borne, water-borne, rabies, etc. Lots of susceptible people around (often all) but they still usually don't spread as long as society functions well enough to maintain controls.
@i_petersen @CathNoakes @BallouxFrancois 对于许多环境控制的传染病而言，情况并非如此，例如。食源性、水源性、狂犬病等。周围有很多易感人群（通常是所有人），但只要社会运转良好以维持控制，它们通常仍不会传播。