AIDS raised the prospect that the threat from infectious disease might come not from the reappearance of old diseases, but from the sudden emergence of new ones, or at least unrecognized ones.

艾滋病的出现表明了这样一种前景，即传染病的威胁有可能并不是来自于以前发生过的疾病的又一次发作，而是来自于新病种或者至少是未曾被发现的病种的突然出现。

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