It may kill fewer people in one fell swoop than a raging flood or an extended drought,but once it takes root in a community,it often defies eradication and can invade other areas.

• 它一次性猛烈的爆发造成的死亡也许没有一次狂怒的洪水或者一次长期的旱灾吞噬的人多，但是它一旦在一个地区生了根，就难以根除并会蔓延到其它地区。