1. The recent outbreaks of cholera are a timely reminder that this disease is still a serious health hazard. 最近几次爆发的霍乱是一个适时的提醒，该疾病依然是个严重的健康危害。
2. However, soon after these fierce outbreaks, the virus died out, at least temporarily. 然而，这些病毒在爆发后不久就消失了，至少暂时是这样。
3. Across vast areas of western North America, increasingly mild winters are causing massive outbreaks of bark beetle. 在北美西部的广大地区，日益温暖的冬季正导致树皮甲虫的大规模爆发。
4. In stands dominated by trees such as aspen, however, incipient gypsy moth outbreaks are quickly suppressed by viral epidemics. 然而，在以白杨等树为主的林分，最初的舞毒蛾爆发很快就被病毒流行病所抑制。
5. There are several hypotheses trying to explain that outbreaks but none have elements of the truth because they contradict each other. 有几种假说试图解释这种疾病的爆发，但没有一种假说是正确的，因为它们相互矛盾。
