Fishes are considered one of the most valuable nutritive, tasty, palatable, cheap and easily digestable protein for man. Fishes can compensate shortage of other animal proteins which arise from rapid increase of human populations, particularly in developing countries, and also from dramatic impacts of emerging infectious diseases on livestock and poultry production, ranging from Bovine Spongiform Encephalopathy to Avian Influenza. From the public health point of view, consumption of fishes infected with the larval stages of some parasites represents a human hazard. Freshwater fishes are considered one of the most important sources of parasitic infections of man and fish-eating mammals, particularly when the waters of rivers and lakes increasingly are polluted.