How did the flu virus affect the U. S. Military?

It claimed alot of lives

Explanation:

The flu depleted and demoralized troops, and may have diverted military and political leaders from fighting the war to combating disease. It ultimately killed more American military personnel than did enemy machine guns and artillery ...

An estimated 675,000 Americans died of influenza during the pandemic, ten times as many as in the world war. Of the U. S. soldiers who died in Europe, half of them fell to the influenza virus and not to the enemy (Deseret News).

While it's unlikely that the "Spanish Flu" originated in Spain, scientists are still unsure of its source. France, China and Britain have all been suggested as the potential birthplace of the virus, as has the United States, where the first known case was reported at a military base in Kansas on March 11, 1918