Over two thousand American soldiers died that year. They were killed my disease and frostbite. Many were undernourished surviving on what was called fire cake which was a tasteless mix of water and flour.
I can't give an exact answer. There were 11,000-14,000 soldiers at Valley Forge. At least 2,500 died of disease. I would say about 4000-6000 died. Sorry for not giving an exact number but different...