1.   The sheep come straight in from the damp outdoors but infection must be kept at bay.

2.   Last month, a North Dakota rancher agreed to kill his flock after one sheep came down with scrapie.

3.   The sheep came from an area of Belgium where BSE has been found.

4.   The test results mean the sheep at one time came into contact with the virus.

5.   It means the sheep at one time came into contact with the virus.