Because this is a disease that has the ability to kill many people at once.
Explanation:
According to the text shown in the question above, we can see that the disease known as the Spanish Flu is very dangerous and can kill a very large number of people in a short period of time. This information can be confirmed by several articles and scientific and historical sources, which show how this disease has a devastating potential. This ability to kill is what causes this disease to receive so much attention from both historians and scientists, who need to document and look for ways to protect the world's population from this disease.
