What is mad cow disease

JAKARTA (JP): Bovine spongiform encephalopathy (BSE) is transmissible to cattle through contaminated meat and bonemeal (MBM) and cattle feed containing infected "specified offals" (brains, nerve or lymphatic tissues).

It is a prion disease; prions are not viruses or bacteria but infectious proteins which have been linked to diseases of the nervous system.

First detected in Britain in 1986, the disease has an incubation period of from two years to eight years. It reached a peak in 1992 and 1993 when at least 100,000 cattle in Britain had to be slaughtered in order to stop its spread.

There is also evidence that BSE affects other livestock, with prion agents infecting other mammals and birds. The first case of feline spongiform encephalopathy (FSE) was recorded in May 1990 in Britain. There were 52 more FSE cases by July the same year, infections which experts concluded almost certainly came from contaminated pet food.

The United States, which accounts for almost 50 percent of beef imports to Indonesia, has no recorded cases of BSE. However, some experts have warned that strains of the disease can be found in deer, elk, mink and sheep -- with the possibility that carcasses of such animals may be found in animal feed.

Although it is almost impossible to link BSE to the new variation of Creutzfeldt-Jakob disease (CJD) in people, many doctors in the west are convinced they are related. CJD has been recorded since the 1920s, particularly in areas with high consumption of offal; a prion-disease variation was long recognized in parts of Algeria, where sheep's heads, including their eyes, are delicacies.

However, the variations recorded in Britain in the 1980s caused concern because the people affected were much younger than usual victims of CJD. (Tri Hafiningsih).