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Bovine Spongiform Encephalopathy (BSE) (Mad Cow Disease)

Introduction
 
1. The occurrence of Bovine Spongiform Encephalopathy (BSE) or Mad Cow Disease in some European (EU) countries in recent years has become a focus of public attention.
   
2. The EU countries have implemented comprehensive control and surveillance measures to prevent the spread of the disease. Hong Kong has also taken corresponding measures to protect public health.
 
What is BSE or Mad Cow Disease
 
1. BSE, also known as mad cow disease, is a progressive and fatal brain disease of cattle first reported in Britain in 1986. It is characterized by spongy like changes in the brain and spinal cord of the affected animals with an average incubation period of about 4 to 5 years.
   
2. One generally accepted theory suggested that a self-replicating protein known as prion causes the disease. Prion is resistant to freezing, drying and heating at normal cooking temperature. It is also unlikely to be inactivated by normal pasteurization and sterilization.
   
3. Epidemiological studies suggested that the spread of BSE might have resulted from the use of ruminant feed containing ruminant-derived meat and bone meal
   
 
The Risks of BSE
 
1. In March 1996, a new disease known as Variant Creutzfeldt-Jakob disease (vCJD) was reported in the United Kingdom (UK) affecting human with characteristic spongy degeneration of the brain
   
2. Epidemiological evidence suggested that vCJD is strongly linked with exposure to the BSE agent, and probably through ingestion of food contaminated by the central nervous system tissues of bovines affected by BSE.
   
3. vCJD is different from the traditional form of Creutzfeldt-Jakob disease (CJD). The traditional CJD is a rare neurological disease of human and is not associated with the consumption of beef.
   
4. Tissues derived from spinal cord, brain, eyes, tonsils and intestines of cattle, sheep and goat are regarded as Specific Risk Materials in EU countries and should be handled with care.
   
5. Nevertheless, according to the information of the World Health Organization, infectivity has not yet been detected in skeletal muscle tissue. Reassurance can be provided by removal of visible nervous and lymphatic tissues from meat. Furthermore, milk and milk products are considered safe. Tallow and gelatin are also considered safe if prepared by a manufacturing process that has been shown experimentally to inactivate the transmissible agent.
 
Situation in Overseas Countries
 
1. Since 1986 and up to December 2000, approximately 180,000 cases of BSE have been reported in the UK. The incidence was at peak in 1992 with an annual case number of more than 37,000. Nevertheless, the incidence has fallen sharply to about 1100 cases in 2000 due to implementation of a series of active control measures by the local authorities. This represented approximately 50% decrease compared to that in 1999.

   
2. BSE cases have also been reported in some EU countries. Up-to-date information of BSE cases can be obtained from the website of the Office International des Epizooties: http://www.oie.int/eng/info/en_esbmonde.htm.

   
3. Recently, there has been an increase in the number of BSE cases reported in France and Germany. This was due to the introduction of active and improved surveillance measures, and the stepping up of tests for BSE in these countries.
   
4. As at December 2000, some 80 cases of vCJD have been diagnosed in the UK, three in France, and one in the Republic of Ireland. No cases have been reported in other countries.
 
Control Measures in EU Countries
 
1. WHO recommended all countries must prohibit the use of ruminant tissues in ruminant feed and must exclude tissues that are likely to contain BSE agent from any animal or human food chain.

   
2. UK has banned the use of ruminant proteins since 1988, and cattle suspected of having the disease were subsequently destroyed and incinerated.
   
3. The European Commission (EC) also put in place a series of very comprehensive measures to combat BSE. These measures include the requirement for removal and destruction of Specific Risk Materials from cattle, sheep and goat from 1 October 2000.

Situation and Regulatory Measures in Hong Kong
 
1. So far, no cases of vCJD, which is closely related to exposure of BSE in cattle, have been reported in Hong Kong.

   
2. The import of beef is governed by the Imported Game, Meat and Poultry Regulations, Cap.132. An official health certificate stating that the meat is fit for human consumption must accompany each consignment of imported beef.
   
3. The Food and Environmental Hygiene Department (FEHD), in line with recommendations of the relevant international authorities, including Office International des Epizooties and WHO, has imposed additional sanitary requirements on beef products imported from EU countries which have reported cases of mad cow disease to prevent and control the spread of the disease in Hong Kong. Such BSE-specific safety assurance attestation should be incorporated in the health certificate accompanying each consignment of beef.
   
4. Under the present requirements, importers have to obtain prior approval from FEHD before importing beef products into Hong Kong from countries with history of mad cow disease. In addition to reporting explicitly the exporting country's mad cow disease status, importers are required to submit health certificates issued by recognized authorities stating the meat-bone-meal is not used to feed cows in the exporting country, that all cows have passed ante-mortem inspection by professional staff and that specific high risk parts like brain and spinal cord have not been included in beef products for export. The consignment in question can only be imported into Hong Kong after FEHD has assessed and approved the application. On arrival to Hong Kong, the beef products will first be held. FEHD will check the health certificates and inspect the products to ascertain that no specific high-risk parts like brain and spinal cord are contained therein before releasing the beef products for sale.
   
5. The majority of beef imported to Hong Kong are from BSE free countries such as the Mainland, USA, Canada, Australia and New Zealand.
   
6. FEHD would continue to monitor the situation and take appropriate control measures where necessary.

 

Risk Assessment Section
February 2001

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