OT Wrote:
As I understand it the tests only show that the disease hasn't manifested itself in the animal- not that it can't be incubating the disease- which could show up in later years...
Wrong OT - the test will identify the presence of PrPsc in the animal, regardless of age, providing the PrPsc has replicated to sufficient numbers and that typically will not take too long after the first infection by whatever means it may have occrred. The urine that filters the blood, will exrete the PrPsc along with the normal PrP and they will both be detected.
Also, for clarification, we have suggested that a urine sample be taken from the animal within a wekk or so of it being slughtered and then, during the sluaghter process, a hypodermic needle will take another sample from the exposed bladder and this will act as the confirmatory test for the animal. The first sample is logged and tagged to be from a specific animal and the second sample is logged as taken from the same animal. This will require that the animal is tagged as it enters the slaughterhouse or existing ID tag info is kept on the animal at least until the sample is taken and the results are back. So what if the animal goes from that stage to storage for a brief time until the test result is back? The most important aspect of this is that the ID of the animal and the sample must be precisely matched at all times including the time that the sample remains in cold storage - approxiamtely 3 months after the animal is processed. This appears to be long enough to allow for the period that encompasses the routing from the pasture to the plate!!
If the PrPsc has not manifested itself in the animal it could be concluded that the animal is BSE free!! The term "manifest" is such a lose word in this sense. It could mean that the animal is BSE free and therefore shows no clinical signs and having BSE could mean the the animal is infected but shows no symptoms of infection.
As for muscle cuts - tests have been done on muscle that formed part of an homogenate in saline. The tests were conducted in the UK and in Scotland. The results showed that muscle cuts, shanks and rumps and tails contained PrPsc in the meat. The contamination from the blood appears to have infitrated the entire animal and this has occurred long before the animals displayed the ataxic symptoms of shaking and falling. To all intents and purposes, the animals tested were known to be carriers from the tests performed on their brain tissues, but displayed no outward symptoms and yet PrPsc was detected in blood, muscle and other tissues, including the brain, tongue, eyeballs, saliva glands. spleens, liver and spinal fluid, to name but a few. As far as I know, the results of these tests have never been formally published. I will however, try to come up with some info.