The 1918 Influenzia, International, 40-50 Million Casualties
The 1918 global influenzia, also known under the more famous name “Spanish Flu” was an unusually severe and deadly form of influenza that was spread across the world at the end of the First World War and lasted for two years until 1920. The flu spread like wildfire, often through the country’s soldiers, and nearly a third of the world’s population was infected in the course of a year. What is unusual about this epidemic is that it primarily affected young people; the smallest risk group for flu diseases. The epidemic ended up taking 40 million deaths from all over the world.
Despite its name, the flu did not originate from Spain, but it was the country where it first received a large press coverage, and therefore came to be associated with this country. Before it reached Spain, the disease had already affected other European countries that were involved in the World War like France, England and Germany.
It was long unknown which virus was behind the pandemic, but in 1998, pathologist Johan Hultin brought together some samples which contained virus from the lung tissue of a woman who died in 1918 of the Spanish Flu, as her her body had been preserved in permafrost in Alaska. The samples were sent to a research team in the United States, led by Dr. Taubenberger, who later managed to isolate the virus in one of Hultins samples.
The research showed that the virus in the Spanish Flu caused an overreaction of the immune system by activating genes related to apoptosis (programmed cell death), which normally is an effective defense against infections. In this case, the cell death could be so large that large parts of the lung epithelium was destroyed, which is both fatal and opens the door for fatal bacterial pneumonia. This may explain the observation that it was mainly healthy people who were most affected by the disease.