How is BSE transmitted?

The route of transmission of BSE is still not proven. It is thought so far that cattle may have became infected with BSE when fed meat and bone meal produced from the BSE-infected carcasses of dead or slaughtered animals. An hypothesis suggests that the first BSE cases were due to the feeding of cattle with scrapie infected meat and bone meal. Other possible routes and causes of transmission have still not been ruled out.

Transmission of BSE from live animal to animal has not been demonstrated. Vertical transmission from cow to calf is a very rare event.