The Spanish influenza pandemic of 1918 caused well over fifty million deaths. The epicentre undoubtedly was China, where gene mixing of different virus strains occurred amongst aquatic, migrant birds. But where and when did the virus first infect (or spill over to) a human being? We take, as our starting point, a paper demonstrating that an infection causing the same symptoms as the influenza virus was widespread in New York during the winter of 1917-1918. The authors of that paper went on to suggest that the virus had probably reached North America from Europe, in the context of troop movement during World War I. Our own researches have focussed on this point. We show that outbreaks of serious respiratory disease, local in nature but causing unusual patterns of mortality, were indeed reported by scientists and doctors in army hospitals in England and in France, well before the first wave of the pandemic had arrived. We use the records of these hospitals, now held in the National Archives, to trace the progress of this disease amongst the individuals who fell ill. We examine contemporary reactions to this minor epidemic - an epidemic, we suggest, which acted as a herald wave of the pandemic yet to come. The latter part of our paper addresses the second question, as to how troop movement across the North Atlantic, once the United States had entered into war, may well have enabled the virus to spread from Europe to North America.
Gill et al. (Wed,) studied this question.