Researchers at the Canadian Food Inspection Agency studied macaques, monkeys that are known to be susceptible to the same prion diseases as humans. They fed the macaques venison, or deer meat, infected with chronic wasting disease. After three years of eating a total of 5 kilograms of infected venison each, three out of the five macaques were found to be infected with CWD. The human equivalent would be eating one 7-ounce steak per month.