by Mopes

Created on: January 30, 2009

The 1918 flu epidemic, more commonly known as the "Spanish flu" was a devastating event in human history. This outbreak spread rapidly and in the first 25 weeks was responsible for the deaths of nearly 25 million people. With the epidemic lasting over two years, from March 1918 to June 1920, it has been estimated to be responsible for up to 100 million deaths.

The strangest thing about the strain of influenza responsible is that it seemed to target healthy adults. Most flu strains tend to cause sickness in children and the elderly; people with weakened immune systems. This particular strain caused more deaths among healthy young adults, than those with a weakened immune system. The most common theory behind this is that the disease killed through something called a cytokine storm.

A cytokine storm is a bodily reaction that causes the body's immune system to severely overreact to a pathogen. In this case, the flu virus itself wasn't nearly as deadly as the body believed, but the immune response is so great, that the body essentially kills itself. This would explain why people with healthy immune systems were such a high proportion of Spanish flu related deaths.

The deadliness of the disease wasn't necessarily the cause of the outbreak, though. World events at the time could easily be blamed for the speed at which the disease spread. When the flu was first observed in Fort Riley, Kansas, it quickly spread to New York, and then onto Europe. In 1918, World War I was still under way, and this meant that many soldiers were living in very close quarters. If one person got sick, it could spread very quickly across an entire camp. Also, the massive troop movements inherent to war did much to hasten the spread across the continent. One infected group could easily spread the disease to every community in their path.

The spread wasn't only limited to Europe, though. In fact, the pandemic was recorded all over the world. Some populous areas that were hit, were not hit nearly as hard. Australia only documented approximately 12,000 deaths, while Japan had a mortality rate of less than 0.5%. Australia had limited contact with most of the world at the time, and Japan blocked off travel to the main islands as often as they possible could.

With these facts, it's easy to blame the sudden spread of the Spanish flu primarily on the new forms of travel associated with the time. World War I and the general convenience associated with new forms of travel made it far easier for a new strain of influenza to travel rapidly throughout the world, infecting a huge number of individuals.

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