Sporadic occurrence of atypical BSE occurs without the prior presence of the disease.

The atypical BSE - a cattle disease that seems to occur spontaneously, without carrying any known health threats, carries the same damaging trade implications as classical BSE. Regardless of the plans of the Australian trade defense, it may not be able to stop domestic cases of atypical BSE.

While the probability of classical BSE being transmitted into the Australian herd nears zero, atypical BSE poses greater implications to the beef industry, due to the potential effect on trade. Currently, the international trade policy treats the two forms of BSE in the same punitive way.

Senior Commonwealth vet Dr Reg Bulter, told the Global Biosecurity Conference in Brisbane last week, That, in my opinion, definitely needs to be changed. He said, current evidence show that atypical BSE is sporadic in nature, meaning it dose not depend on the prior presence of the disease, for it to occur.

Presently, the strongest pattern seen in 51 cases of atypical BSE which is related to age, said Dr Butler. All cases have appeared in cattle older than 8 years, except for a single case in Japan.

Atypical scrapie, the related disease seen in sheep and goats, has been first identified in 1998, is found to be 100 times more common.

The risk of getting an atypical scrapie case is related to flock size, said Dr Butler. While the World Organization for Animal Health (OIE) has ruled that atypical scrapie is a separate disease to classical scrapie, and reporting cases of atypical scrapie does not carry dire trade implications associated with classical scrapie, the same can't be said for atypical BSE, said Dr Butler.

David Adams, a retired vet, former worker with the Office of the Chief Veterinary Officer in Canberra, told NSW Farmers Association meeting on Tuesday that it was in the interest of Australia to reach for a clear policy distinction between both types of BSE.

He said, I think we need to be working on this at an international level. We don't carry the BSE baggage that the United Kingdom and European Union have, and we can play an important role in influencing the discussion. Classical BSE is virtually gone from the world, said Dr Adams.

He said the only mode of transmission is through feeding of meat and bone meal; stop that and the disease can be stopped. However, Dr Butler told the Global Biosecurity conference that some work remained to be done on atypical BSE.

It is still uncertain whether primates including humans can get the disease by eating damaged proteins and scientists are also in doubt whether the damaged prions responsible for atypical BSE are confined in the central nervous system, or can be located at other parts of the body.