The disease spread quickly, as troop ships transported the disease to many parts of the world, including Germany, France, and England. Around the same time, 8 million people throughout Spain became ill with a similar strain of influenza; hence, the name. The disease continued to spread across Africa, South America, and Canada. Within a few months more people had died of Spanish flu than of the Black Death in the Middle Ages
1
Causes of Influenza
Like the common cold, the flu is transmitted by viruses—specifically, influenza viruses—that attack about 10% of people during a normal winter. Because influenza viruses are much more aggressive and destructive than cold viruses, they demand a more forceful reaction from the immune system, which can weaken the body.
There are three types of the flu virus: A, B, and C. Flu viruses mutate rapidly, which means the immune system can no longer recognize the pathogens. Therefore, it is difficult for researchers to develop effective vaccines that provide lifelong immunity.
Protection Against Influenza
The flu can be life threatening, especially to the elderly. Children or those taking medication for a chronic condition are also vulnerable due to potentially weakened immune systems. The single best way to protect against the flu is to get vaccinated. But as history shows, the virus constantly mutates and changes. So you should strongly consider getting a yearly vaccination to help keep the flu out of your future.
1
Potter, C.W. A history of influenza, Journal of Applied Microbiology. 91:572-579. 2001.