Bovine spongiform encephalopathy (BSE) revisited

Since 2001, bovine spongiform encephalopathy (BSE) has continued to attract considerable scientific interest. It is now widely accepted that abnormal prions (proteinaceous infective agents) in bovine products can transmit BSE between cattle and are the cause of (new) variant Creutzfeldt—Jacob disease (vC JD) in humans. A better understanding of transmissable spongiform encephalopathies (TSEs) and how they propagate will affect how we feed and manage our livestock and prepare their products for entry into the human food chain; it should also advance our understanding and management of vCJD. This disease is invariably fatal although recently there have been reports of possible immunization using monoclonal antibodies or use of drugs to prevent infection or extend the quality of life of those infected. To date about 150 people have died of vCJD, mainly in Europe. Predictions of future deaths from vCJD have been revised downwards but are still uncertain. Countries outside the EU that have newly reported BSE cases include Israel, Japan and most recently Canada; it is probable that there are cases in other Asian countries that have not been detected. The case in Canada has again raised questions about the possibility of cross—species transmission (to humans or livestock) of TSEs such as chronic wasting disease (CWD), a widespread disease of farmed and feral deer and elk in Canada and the USA. All evidence indicates that Australia is free of BSE, but we must remain proactive. Safeguards are in place that should prevent the entry of BSE infection. Veterinary oversight and contingency plans should maximize the chances of our quickly diagnosing and eliminating BSE from domestic cattle if, as seems unlikely, a case of BSE should be detected.