Nearly two weeks after a 28-year-old researcher died from a mysterious infection while working in a Russian plague research laboratory, health officials around the world are still waiting for answers. 近两周前，一名在俄罗斯鼠疫研究实验室工作的28岁研究员因不明感染死亡，世界各地的卫生官员至今仍在等待答案。…