Normal prions in nerve tissue of cattle, humans, cats, or other animals have to be deformed as the initial stage of spongiform encephalopathies. As discussed above, the mutant prion could occur spontaneously in a population at a rate of one in a million. The predilection for it can also be an inherited trait, which is related to the gene sequence for the prion protein and can be found in 38% of the human population (53).

The other 62% ?might? be resistant to the disease. However, other research suggests that those in the ?resistant? group might simply develop the disease much later (57).
But what causes a normal or susceptible prion to turn into a lethal one? One hypothesis that has been put forth is that this could be caused by organophosphates. Nerve damage is known to be caused by exposure to these potent chemicals, which were originally developed by the Nazis during the war as a toxic nerve agent.

If organophosphates are involved, the highly reactive free radicals in the chemical could deform normal or susceptible prions. According to some researchers, the deformed prions would become more prone to binding with manganese, and it is this combination that makes them dangerous. (One form of organophosphate even contains magnesium.) It is postulated that manganese-bound prions then become rogue prions that have the ability to deform other normal prions in a chain reaction that eventually destroys the brain.

This hypothesis contends that TSEs are likely linked to environmental conditions rather than prion-contaminated feed. The researchers discovered that prions require copper to develop properly. If copper is low and exposure to high levels of manganese occurs, the prion may bind to manganese and turn into the fatal form that eventually burns holes in the brain.

A small cluster of scientists argues that the environmental imbalance of copper and manganese are common factors among TSE cases around the world. This could explain the observance of scrapie in sheep and chronic wasting disease in deer in Colorado and Wyoming, where the deer feed on copper-starved soil. The deer could also have been exposed to the insecticide and then obtained the manganese from their diet of pine needles, which contain this element. The Colorado Division of Wildlife denies that the deer were fed meat products. (52) On the other hand, the researchers advocating spread of TSE by contaminated feed, have found evidence that scrapie may be passed among sheep by their feeding on TSE-contaminate grass (53).

Manganese poisoning could be linked to the soil, water or even industrial emissions. In cattle, the damaged prions would be capable of binding with manganese present in animal feeds (especially chicken manure), feeds grown on copper-depleted soil, or in mineral licks, or manganese sprayed on the land. This would convert normal prions into the rogue prions that cause the neurological damage of BSE. Therefore, the spongiform encephalopathies may be linked to modern industrial development. Manganese emissions from steel or petrochemical refinery processing may also have a connection.