Bovine spongiform encephalopathy (BSE)

Bovine spongiform encephalopathy (BSE) is a disease in cattle. It belongs to a group of fatal neurodegenerative diseases affecting humans and animals called transmissible spongiform encephalopathies (TSEs). They are caused by the abnormal form of a cell protein called prion protein (PrP). Since the discovery of BSE in cattle, only two cases have been confirmed in species other than cattle: one goat in France and one goat in the UK.

BSE was first discovered in 1986. Since 1989, the European Commission and the EU Member States have put in place a comprehensive series of measures to manage the risk of BSE in the EU.

BSE has three different presentations: classical BSE, H-type atypical BSE and L-type atypical BSE. Classical BSE is the only form that can be transmitted to humans through the consumption of contaminated meat causing variant Creutzfeldt-Jakob disease, which was first diagnosed in 1996.

Classical BSE

The epidemic of BSE (now known as classical BSE) started in 1986 in the UK. It was first a European and later a global problem affecting cattle. Epidemiological studies suggested that the source of the disease in cattle was feed containing BSE-infected processed protein (meat and bone meal).

The common symptoms of classical BSE in cattle include behavioural changes, lack of coordination, difficulty in walking or standing up, decreased milk production and weight loss. However, the disease has also been detected in animals showing no symptoms.

Milestones

July 2018 EFSA publishes a scientific opinion on the risk of BSE posed by processed animal protein (PAP) in feed.

July 2017 EFSA publishes a scientific opinion on the origin of the 60 cases of classical BSE reported in cattle born after the EU ban on the use of animal proteins in livestock feed was enforced in 2001. Experts concluded that contaminated feed was the most likely source of infection. A second possibility was that contaminated feed ingredients may have been imported from non-EU countries. They could not rule out other causes due to the difficulty of investigating individual cases.

July 2014: EFSA develops a laboratory protocol on how to conduct new studies for investigating the presence of the agent of Atypical BSE in tissues of infected cattle.

October 2012: EFSA gives scientific and technical assistance on the minimum sample size to test should an annual BSE statistical testing regime be authorised inhealthy slaughtered cattle

Role

EFSA’s role is to provide independent scientific advice to risk managers on all animal and public health-related aspects of BSE in the EU. Most of EFSA’s work is based on requests from the European Commission.

EFSA has carried out comprehensive scientific work regarding BSE. The Panel on Biological Hazards (BIOHAZ) has provided scientific advice on different aspects related to BSEsuch as:

• The review of the EU surveillance system
• The review of the BSE monitoring system in specific countries
• Assessments on the infectivity in the tissues of small ruminants (sheep and goats) and atypical BSE
• Risks associated with animal tissues harbouring most of the infectivity (specified risk materials).Risks associated with the use of animal proteins in animal feed

EU framework

In the EU, a large body of legislation is in place to protect humans and animals from BSE and other animal TSEs. All EU measures on animal TSEs are consolidated in Regulation (EC) 999/2001.

The main measures for BSE include:

• A ban on using animal protein in feed given to animals farmed for food production.
• A comprehensive monitoring system, including post-mortem testing of at-risk animals over certain ages.
• Compulsory removal and destruction of tissues containing the highest risk of BSE infectivity, such as the brain and spinal cord from bovine animals over a certain age.
• Following the detection of a positive BSE case, destruction of the carcass.

The European Commission adopted a strategy document – the TSE Roadmap 2 - on transmissible spongiform encephalopathies for 2010-2015, which outlines areas where changes to EU TSE-related measures could be made.

Some of these areas have been actioned and resulted in changes in the legislation given the success of the European Union's efforts in combating(TSEs, such as BSE in cattle or scrapie in sheep and goats.