Cholangiocarcinoma, a tiny parasite that causes the aforementioned cancer in the bile duct years after eating the freshwater fish found in Vietnamese streams. The Veterans Administration has been denying claims for it. Full story in the Arkansas Democrat Gazette, November 26, 2017, page 2. This will most likely affect Army, Marines, and others who served in the jungle and ate the fish when their rations ran out. I was in the Ashau Valley and we washed up in the stream next to the fire base after we would throw a grenade in the water to stun the leaches. Didn't eat any of the fish though.