The Spanish flu of 1918, for example, swept the world for a year and a half and then suddenly disappeared without a trace. Although epidemiologists from around the world spent many decades searching for this deadly virus and monitoring possible outbreaks, they failed utterly to find the key to its origin in 1918.
像是一九一八年西班牙流感橫掃全球一年半後，突然銷聲匿跡，這麼多年來，任憑全球疾病專家努力地監控、尋找，卻怎麼樣也無法還原當年這隻病毒肆虐的關鍵真相。