Is it true that all cases of BSE have been traced to mammalian-derived feed?

The claim that all cases of Bovine Spongiform Encephalopathy (BSE), commonly known as mad cow disease, have been traced to mammalian-derived feed is not accurate, making the answer correct in stating that this statement is false. BSE is primarily associated with the consumption of feed that contains rendered protein from infected cattle. However, not every incidence of BSE can definitively be linked to such feed sources.

Additionally, while many cases of BSE have been identified with a clear connection to this type of feed due to its role in the introduction of the prion responsible for the disease, there have been exceptional instances where the source of infection could not be established, or the exact transmission route was not clearly defined. This indicates that while mammalian-derived feed has been a significant factor, it is not the sole pathway for the transmission of BSE in all cases, allowing for the correct classification of the statement as false. Thus, it's important for students to recognize the complexities involved in tracing the origins of diseases like BSE.