You might not know have any symptoms, you might just have a latent source of the microorganism somewhere in your body.

你可能没有任何症状,微生物可能只是在体内某处,暗中不断滋生

耶鲁公开课 - 生物医学工程探索课程节选

In fact, I do this as well, I mean I have water with me and I have no idea why because I'm not particularly dehydrated.

事实上,我也整天带着水壶,我是说我随身带水,但又不知道为什么要带,因为我并没有特别的脱水症状

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There were no asymptomatic carriers.

也没有无症状的病毒携带者

耶鲁公开课 - 生物医学工程探索课程节选