George Washington and his soldiers, such as they were, established camp at Valley Forge, Pennsylvania. It was a week prior to Christmas. They stayed there until June, 1778. During those six months as many as 2,000 men died. It was cold during the winter months, but the men didn’t die due to the weather.
The close and unsanitary conditions at the camp became a breeding ground for dysentery, typhus pneumonia, and typhoid. But the main killer was not the disease either. The main problem was the surrounding farmers. Many of them chose to sell their produce to the British instead of the Army for the new United States. It seems they trusted the English sterling more than any recently minted American money.