Spanish Flu of 1918 to 1919
The Spanish Flu of 1918 or the influenza pandemic killed between 20 and 40 million people in 1918 and 1919. The Spanish Flu was more devastating than World War I, in terms of the numbers lost. The Spanish Flu was exceptionally virulent, and unusually lethal. Like other plagues, this one spread with shipping, trade, and the movement of armies.
Fatality rates were around 2.5 percent; in comparison to Yersinia pestis, that seems quite low; however, the illness spread very easily, so infection rates were astonishing. In addition, the majority of deaths came in individuals between 20 and 40 years of age. This is in direct opposition to the normal deaths associated with influenza, which typically kills the very young and very old.
There is relatively little understanding of the specifics of the Spanish Flu, but it is believed to have originated with a genetic mutation in China. This was not the first flu pandemic; a virulent strain of influenza had impacted much of the world in 1890. Those that had survived the flu in 1890 had some resistance in 1918.
Treatments available were minimal; scientists were aware of and understood microorganisms, but believed that influenza was bacterial, not viral. Initial symptoms included a high fever, sore throat, body aches, and headache. Vomiting and diarrhea was sometimes present. Many people recovered, then relapsed, with much more serious respiratory symptoms, including pulmonary hemorrhage.
Efforts were made to produce a vaccine, but these were ineffective at the time. The disease moved quickly, causing economic disruption, but left as quickly as it came, typically exhausting itself within a single community within just a few weeks. The pandemic was largely forgotten, and more than a decade would pass before the isolation of the influenza virus.