1.   Infected cows have to be separated off from the herd.

2.   According to officials from the Ministry of Agriculture and Food, the single infected cow was descended from British stock.

3.   An outbreak of the disease in Great Britain has been linked to eating beef of infected cows.

4.   A British laboratory subsequently confirmed the diagnosis, and agricultural ministry officials are now attempting to trace the whereabouts of other possibly infected cows from the same Hokkaido herd.

5.   After symptoms appear, the infected cow dies or must be destroyed within six months.

6.   But people can become sick with it by drinking unpasteurized milk from an infected cow.

7.   Can humans get a prion disease by eating meat from infected cows?

8.   Farmers could then use it to pick out infected cows to be destroyed.

9.   Meat from one infected cow is mixed with many other cows, so that one bad cow can cause hundreds of bad stomachs.

10.   No virus has ever been found in infected cow brains.