As the First World War was grinding to its end in 1918, reports started to emerge of an infectious disease in the trenches, army barracks and medical hospitals crowded with soldiers. The first outbreaks were reported in March 1918, although initially doctors weren’t sure if it was flu or some other infectious disease. The Spanish flu pandemic ranks with the Justinian plague and the Black Death as one of the worst medical disasters in human history. It spread around the world