Ebola, Lassa, Marburg and HIV are frightening examples of these

Ebola, Lassa, Marburg and HIV are frightening examples of these deadly organisms. The death tolls where they strike are sobering. Even the flu virus can be a killer. We’ve known about it for many decades now, but flu experts are still involved in a full-time race to keep up with the virus as it mutates.
【正确答案】：埃博拉、拉沙、马尔堡病毒以及艾滋病病毒，都是这些致命微生物的可怕的例子在它们肆虐的地区，死亡人数之多令人警醒。即便是流感病毒都能够致人死命。虽然我们早在几十年前就发现它，可是流感专家们仍在全力与时间赛跑，以便跟上流感病毒变异的速度。