Examination on total of 450 samples including fresh water fishes, eels, shrimps, crabs and frogs, and 300 fresh water snails in 3 study sites of Nam Dinh, Hanoi and Hoa Binh City were done and analyzed. The result showed that, the infection rate of fish borne trematode in fishes was 10 percent in Nam Dinh, 3.2 percent in Hoa Binh and 2 percent in Hanoi. The infection rate of Spirometra erinacei in frogs was 8 percent in Nam Dinh, 4 percent in Hoa Binh and 10 percent in Hanoi. The infection rate of Gnathostoma in eels was 2 percent in Nam Dinh and 2 percent in Hanoi
infection rate of Paragonimus larvae in stone crabs was 4 percent and in Melanoides snails was 1. 7 percent. Treatment for waste water before feeding fish is needed and no eating raw aquatic food.