Below is an article written by Henry L. Fox who was in World War 1 and participated in Trench Warfare. He describes "Cooties", "Rats", "Mud" and "Gas Masks". Cooties are birds that pester you at all times, they are basically unreasonable birds. Rats are basically just large rats. They are as big as cats and carry many diseases causing large number of illnesses throughout out the army. "Mud Fever" is what they called the hatred for the mud during rainy seasons. The men hated going out to drill during rainy season and they only way to get out of it was going to the infirmary. Lastly gas masks were just a convenient addition to your protection. American gas masks were ahead of the game and were very useful.
The two picture of propaganda were very popular during the war. Propaganda usually was presented to the public making them feel guilty in this case. By doing this they will have more people join the army to go fight over seas or have them do something to help the troops.