The changes in investor mood often happen in a flash-an infection of outlook that can seem as swift as an epidemic of flu.

投资者的心境变化通常都在须臾之间，对未来的看法改变可以像流行感冒一样迅速传播。

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The outbreak of swine flu that was first deteccted in Mexico was declared a global epidemic on June 11, 2009.

2009年6月11日，墨西哥首次爆发的猪流感被宣布为全球流行病。

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Now utopia has grown unfashionable, as we have gained a deeper appreciation of the range of threats facing us, from asteroid strike to epidemic flu and to climate change.

现如今，这种乌托邦空想已经过时了，我们对所面临的威胁有了更深刻的认识，从彗星撞击到流行感冒，再到气候变化。

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Scientists also completed similar research on victims of the Spanish flu epidemic in nineteen eighteen.

VOA: special.2010.06.29

Growing fears of a flu epidemic across the Arab world is prompting Arab health ministers to restrict participation in this year's annual Hajj.

VOA: standard.2009.07.23

He notes that except for the death toll in Mexico, most of the swine flu cases reported since the current epidemic struck have been relatively mild.

VOA: standard.2009.04.28

As luck would have it, though, the new advice agrees more closely with the recommendations of the CDC's advisory committee on immunisation practices about the best approach to the epidemic of N1H1 swine flu that is now circulating.

ECONOMIST: Influenza vaccination

We exchanged letters every Christmas until he passed away in the flu epidemic of 1918.

NPR: Excerpt: 'True Grit'

The final great epidemic of the 20th Century was Russian flu, which hit Britain in 1977.

BBC: The flu virus that nearly killed me