PARMA, Italy – Contaminated feed is the most likely origin of isolated cases of bovine spongiform encephalopathy (BSE) infections, the European Food Safety Authority said.

EFSA found 60 cases of classical BSE have been reported in cattle after the European Union enforced a ban on animal proteins in livestock feed. Classical BSE is transmissible to humans. The number of classical BSE cases dropped from 554 reported in 2005 (after the ban) to two in 2015.

“EFSA experts concluded that contaminated feed is the most likely source of infection,” the agency said in a summary of the research. “This is because the infectious agent that causes BSE has the ability to remain active for many years. Cattle may have been exposed to contaminated feed because the BSE infectious agent was present where feed was stored or handled. A second possibility is that contaminated feed ingredients may have been imported from non-EU countries.”

EFSA was unable to rule out other causes due to factors such as the long incubation period of the disease and lack of detailed information on individual cases. However, the agency made several recommendations aimed at maintaining and strengthening the EU’s BSE surveillance program to monitor the evolution of the trail of the BSE epidemic; detect a potential re-emergence of BSE and detect a new BSE form in cattle.

The full report is available at: