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> The Spanish Flu Issue: 2006-2 Section: Biology



No sooner had the First World War ended than the Spanish flu pandemic appeared. It is thought to have been one of the most deadly pandemics so far in human history. It affected the whole world between February 1918 and April 1919, and led to the death of about 50 million people.

This viral infection disease was caused by the H1N1 type of influenza virus. It hasn’t been deeply studied since people didn't keep samples of the 1918 strain of influenza. However, after a few years, scientists managed to find out samples from corpses buried in the frozen ground of Alaska.

Although this illness is called Spanish flu, it didn't appear in Spain. Indeed, owing to the Spanish neutrality during the First World War, there was no censorship, so that the media could talk freely about the outbreak of the influenza, and thus warn people. On the contrary, the other countries preferred to concentrate their population on war effort.


The Cell

(1) The H5N1 virus with detail of RNA segment

(2) Flu virus with legend


The real origins are confused, there are two different hypotheses: on the one hand, it might have come from China and it would spread out to Europe because of the Chinese immigrants. On the other hand, it might have come from the USA, from Fort Riley (Kansas), and reached Europe the American troops. The propagation of the disease all around the world was amplified by the First World War armistice and by the return of the soldiers of the colonies. Thus the whole world was affected in only three months.

The virus would come from poultry and it would underwent mutations which allowed it to contaminate mankind. This virus was the father virus, which was very contagious but not really virulent. The virus of Spanish flu developed from the father and it occurred in two steps: the first one from September to December 1918, and the second one from February to April 1919. All the populations had been seriously infected because the virus had become much more virulent and above all, lethal.

When governments realised the fullness of the phenomenon, they decided to forbid some things, such as shaking hands or coughing in public places.

The Spanish flu was highly infectious and deadly because humanity had never experienced such a strain of influenza. The strain was unusual in killing many young and healthy people, unlike common influenza which killed mostly new-borns, disabled people and the old. Old people were immunised thanks to the 1890's pandemic. The more the young people travelled, the more likely they were to be affected, and the spreading of the disease was linked to these journeys.

The main effect of the Spanish flu was the weakening of immune defences, hence an increasing sensibility towards other diseases, which explained the high rate of mortality even though the Spanish flu wasn't directly responsible for death. Symptoms included fever and coughing up blood, caused by severe destruction of the lungs. In later stages, the virus caused an uncontrollable bleeding which filled the lungs, and the patients drowned in our body fluids.


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