Generally, the species barrier provides reasonable protection for non-host animals against infection; even so, Friedland and his team argue, it is possible for a fish to serve as a carrier for the disease without being infected itself. Further, say researchers, it is "possible that eating diseased cow parts could cause fish to experience a pathological change that allows the infection to be passed between the two species." As Mad Cow disease takes decades to show itself in an infected person or animal, conclusive results may not be available until well into the future. Still, Friedland hopes that his article may help sound the alarm and change farmed fish-food before the disease pervades this transmission route.
From my standpoint, simply hearing that the farmed fish industry uses leftover cow products as fish-food is reason enough to change the practice. After all, said Friedland, "Fish do very well in the seas without eating cows."