Before WWI, Frank w. Weed wrote that if there were earlier records about wartime diseases in the USA during the civil war, epidemics might have been foreseen and diarrheas prevented.

Before World War II the majority of fatalities in war were not caused by trauma but by diseases. Common diseases like dysentery, cholera, typhus, typhoid fever, smallpox and the influenza were the major killers of soldiers. WWII marked the transition from infectious to trauma era.

Trauma wounds cause injury to living tissue caused by an extrinsic agents like bullets, shrapnel, or blunt force injuries. Medical advances with blood transfusions, vaccines, and antibiotics caused a shift from infection being the most significant cause of combat fatalities to trauma causing the most deaths.

Modern military history from a medical perspective can be divided into two eras, the Infection Era and the Trauma Era, depending on the etiology of death of the soldiers. The Infection Era began in 1775 and continued until the end of WWI in 1918. Diseases weakened troops and increased their vulnerability in battle. According to military hygienist Alfred A.Woodhull “the sick are for the time as ineffective as the dead.”[1]

[1]Vincent J. Cirillo, "Two Faces of Death fatalities from disease and combat in Americas principal wars, 1775 to present," Perspectives in Biology and Medicine 51 (2008) 121 .

Prior to WWII, infectious diseases spread out ramptly because the trenches lacked sanitation and proper disposal of wastes. On average, the number Disease spread rampantly throughout over crowded camps in which there was a lack of sanitation and disposal of wastes. Soldiers and doctors practiced poor hygiene, which helped spread disease. On average the infectious deaths to combat deaths was 4.34:1 between 1775 and 1918. The highest ratio occurred during the War of 1812 inwhich there was a ratio of 7.5 infectious deaths to each combat death.

After WWI, An average of 1.1 infection deaths to each combat death occurred.

(of 7.5 infectious deaths to each combat death, compared with 1.1:1 in WWII.
www.lemoyne.edu/Portals/11/pdf_content/History_Paper.pd.).The end of the infectious era was marked by influenza pandemic in 1918. This flu outbreak covered the entire world and spread rapidly throughout the armies in WWI Of the U.S. soldiers who died in Europe, half of them fell to the influenza virus and not to the enemy (Deseret News, http://virus.stanford.edu/uda/)..

The Trauma Era began in 1941 and continues today. This presented a shift in which significantly more soldiers died from battle injuries than infections, despite no drastic change in wartime weapons between WWI and WWII,

By the end of WWII only .06(www.lemoyne.edu/Portals/11/pdf_content/History_Paper.pdf) soldiers died from infection to each combat related death

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