Diseases and Deaths Caused by Trenches
Trench Rats

Being built into the ground, trenches were often infested by millions of rats. The trenches had no waste disposal and corpses of dead soldiers all around, which contributed to an unsanitary conditions. These conditions made it the perfect habitat for rats, which also carried more diseases.
Body Lice

Lice was another issue many soldiers faced in the trenches. Although soldiers often tried to be delouse themselves, the lice continuously spread, often inhabiting the seams of soldiers' clothing. One way soldiers attempted to rid themselves of lice was to run a lit candle along the seams of their clothes. The lice also spread more sickness, call the Trench Fever.
Trench Fever

Caused by the lice outbreaks, soldiers also suffered from Trench Fever. Severe pains and high fevers came along with this sickness. Symptoms were very wide-ranged, some resembling typhoid and influenza. Although this fever was not particularly serious, it could take anywhere form five days to twelve weeks to recover.
Trench Foot

Soldiers often suffered trench foot due to a condition caused by fungal infections. Since trenches had cold and damp conditions, the soldiers had poor hygiene. Fungus would form on the foot, which led to soldiers often needing amputation.
Dysentery

Due to the poor sanitation and the irregular supply of drinking water in the trenches, soldiers suffered from Dysentery. They had to get their water either from melted snow and water from shell-holes. This unsanitary drinking water caused bacterial infections in the soldiers' intestines. Symptoms that came along with dysentery were diarrhea, fever, vomiting, and stomach aches. Dehydration from dysentery could result in death.