OldDog/NewTricks
Well-known member
Positive BSE Test Results
http://www.aphis.usda.gov/newsroom/content/2006/03/bsestatement3-13-06_vs.shtml
http://www.aphis.usda.gov/newsroom/content/2006/03/bsestatement3-13-06_vs.shtml
Positive BSE Test Results :(
- Thread starter OldDog/NewTricks
- Start date
ranchwife
Well-known member
OUCH!!!! NOW ALL WE CAN DO IT SIT BACK AND SEE WHAT HAPPENS.............. 
Jason
Well-known member
Like this is a big surprize?
We all knew there would/will be more positives found.
Being open by announcing it right away is the best policy.
Looks like the on farm testing is starting to catch up. Keep it up.
We all knew there would/will be more positives found.
Being open by announcing it right away is the best policy.
Looks like the on farm testing is starting to catch up. Keep it up.
OldDog/NewTricks
Well-known member
Just Got This I have not Read Yet!
This link may work:
http://www.cattlenetwork.com/content.asp?ContentId=22838
Story:
Alert: Positive Result On Western Blot Test
Average reader rating: 0
by USDA Clfford Statement Today 3/13/2006 2:54:00 PM
BSE Alert: Positive Result On Western Blot Test
"We received a positive result on a Western blot confirmatory test conducted at the USDA laboratories in Ames, Iowa, on samples from an animal that had tested "inconclusive" on a rapid screening test performed on Friday, March 10.
"The samples were taken from a non-ambulatory animal on a farm in Alabama. A local private veterinarian euthanized and sampled the animal and sent the samples for further testing, which was conducted at one of our contract diagnostic laboratories at the University of Georgia. The animal was buried on the farm and it did not enter the animal or human food chains.
"We are now working with Alabama animal health officials to conduct an epidemiological investigation to gather any further information we can on the herd of origin of this animal. The animal had only resided on the most recent farm in Alabama for less than a year.
"We will be working to locate animals from this cow's birth cohort (animals born in the same herd within one year of the affected animal) and any offspring. We will also work with Food and Drug Administration officials to determine any feed history that may be relevant to the investigation. Experience worldwide has shown us that it is highly unusual to find BSE in more than one animal in a herd or in an affected animal's offspring. Nevertheless, all animals of interest will be tested for BSE.
"Under USDA testing protocols, surveillance samples are sent to contract laboratories for screening tests. If the sample is found to be inconclusive on the screening test, it is then shipped to our National Veterinary Services Laboratories (NVSL) in Ames, Iowa, for an additional rapid test and two confirmatory tests: the immunohistochemistry (IHC) test, which is conducted by APHIS scientists, and the Western blot test, which is conducted by scientists with USDA's Agricultural Research Service. USDA considers an animal positive for BSE if either of the two confirmatory tests returns a positive result.
"In this instance, the inconclusive result from the contract lab in Georgia was confirmed through a second rapid test at NVSL. Now, the Western blot test has returned a positive result, and that is sufficient for us to confirm this animal to be positive for BSE, which is why we are making this announcement today. The IHC results are still pending and we will release those results as soon as they are available, which we expect to be later this week.
"I want to emphasize that human and animal health in the United States are protected by a system of interlocking safeguards, and that we remain very confident in the safety of U.S. beef. Again, this animal did not enter the human food or animal feed chains.
"While epidemiological work to determine the animal's precise age is just getting underway and is ongoing, the attending veterinarian has indicated that, based on dentition, it was an older animal, quite possibly upwards of 10 years of age. This would indicate that this animal would have been born prior to the implementation of the Food and Drug Administration's 1997 feed ban. Older animals are more likely to have been exposed to contaminated feed circulating before the FDA's 1997 ban on ruminant-to-ruminant feeding practices, which scientific research has indicated is the most likely route for BSE transmission.
"By any measure, the incidence of BSE in this country is extremely low. Our enhanced surveillance program was designed as a one-time snapshot to provide information about the level of prevalence of BSE in the United States. We have conducted surveillance in the United States since 1990 and following the initial positive in December 2003, we developed an enhanced surveillance program. Since June 2004, all sectors of the cattle industry have cooperated in this program by submitting samples from more than 640,000 animals from the highest risk populations and more than 20,000 from clinically normal, older animals, as part our enhanced BSE surveillance program. To date, including the animal in today's announcement, only two of these highest risk animals have tested positive for the disease as part of the enhanced surveillance program.
"As we approach the conclusion of our enhanced surveillance program, let me offer a few thoughts regarding surveillance going forward. I can assure you that we will continue to base our maintenance surveillance testing on international guidelines. Though the nature and extent of maintenance surveillance has not yet been finalized, the incidence of BSE in this country remains extremely low and our interlocking safeguards are working to protect both human and animal health and we remain very confident in the safety of U.S. beef.
"As we move forward with the epidemiological investigation that has been initiated today into this case of BSE, we will continue to be very transparent in sharing information with the public and with our trading partners around the world."
This link may work:
http://www.cattlenetwork.com/content.asp?ContentId=22838
Story:
Alert: Positive Result On Western Blot Test
Average reader rating: 0
by USDA Clfford Statement Today 3/13/2006 2:54:00 PM
BSE Alert: Positive Result On Western Blot Test
"We received a positive result on a Western blot confirmatory test conducted at the USDA laboratories in Ames, Iowa, on samples from an animal that had tested "inconclusive" on a rapid screening test performed on Friday, March 10.
"The samples were taken from a non-ambulatory animal on a farm in Alabama. A local private veterinarian euthanized and sampled the animal and sent the samples for further testing, which was conducted at one of our contract diagnostic laboratories at the University of Georgia. The animal was buried on the farm and it did not enter the animal or human food chains.
"We are now working with Alabama animal health officials to conduct an epidemiological investigation to gather any further information we can on the herd of origin of this animal. The animal had only resided on the most recent farm in Alabama for less than a year.
"We will be working to locate animals from this cow's birth cohort (animals born in the same herd within one year of the affected animal) and any offspring. We will also work with Food and Drug Administration officials to determine any feed history that may be relevant to the investigation. Experience worldwide has shown us that it is highly unusual to find BSE in more than one animal in a herd or in an affected animal's offspring. Nevertheless, all animals of interest will be tested for BSE.
"Under USDA testing protocols, surveillance samples are sent to contract laboratories for screening tests. If the sample is found to be inconclusive on the screening test, it is then shipped to our National Veterinary Services Laboratories (NVSL) in Ames, Iowa, for an additional rapid test and two confirmatory tests: the immunohistochemistry (IHC) test, which is conducted by APHIS scientists, and the Western blot test, which is conducted by scientists with USDA's Agricultural Research Service. USDA considers an animal positive for BSE if either of the two confirmatory tests returns a positive result.
"In this instance, the inconclusive result from the contract lab in Georgia was confirmed through a second rapid test at NVSL. Now, the Western blot test has returned a positive result, and that is sufficient for us to confirm this animal to be positive for BSE, which is why we are making this announcement today. The IHC results are still pending and we will release those results as soon as they are available, which we expect to be later this week.
"I want to emphasize that human and animal health in the United States are protected by a system of interlocking safeguards, and that we remain very confident in the safety of U.S. beef. Again, this animal did not enter the human food or animal feed chains.
"While epidemiological work to determine the animal's precise age is just getting underway and is ongoing, the attending veterinarian has indicated that, based on dentition, it was an older animal, quite possibly upwards of 10 years of age. This would indicate that this animal would have been born prior to the implementation of the Food and Drug Administration's 1997 feed ban. Older animals are more likely to have been exposed to contaminated feed circulating before the FDA's 1997 ban on ruminant-to-ruminant feeding practices, which scientific research has indicated is the most likely route for BSE transmission.
"By any measure, the incidence of BSE in this country is extremely low. Our enhanced surveillance program was designed as a one-time snapshot to provide information about the level of prevalence of BSE in the United States. We have conducted surveillance in the United States since 1990 and following the initial positive in December 2003, we developed an enhanced surveillance program. Since June 2004, all sectors of the cattle industry have cooperated in this program by submitting samples from more than 640,000 animals from the highest risk populations and more than 20,000 from clinically normal, older animals, as part our enhanced BSE surveillance program. To date, including the animal in today's announcement, only two of these highest risk animals have tested positive for the disease as part of the enhanced surveillance program.
"As we approach the conclusion of our enhanced surveillance program, let me offer a few thoughts regarding surveillance going forward. I can assure you that we will continue to base our maintenance surveillance testing on international guidelines. Though the nature and extent of maintenance surveillance has not yet been finalized, the incidence of BSE in this country remains extremely low and our interlocking safeguards are working to protect both human and animal health and we remain very confident in the safety of U.S. beef.
"As we move forward with the epidemiological investigation that has been initiated today into this case of BSE, we will continue to be very transparent in sharing information with the public and with our trading partners around the world."
OldDog/NewTricks
Well-known member
Today 3/13/2006 3:38:00 PM
Cattle Alert: NCBA Statement On Positive BSE Test Result
http://www.cattlenetwork.com/content.asp?contentid=22839
"The United States Department of Agriculture (USDA) confirmed this afternoon a positive test result as part of its enhanced surveillance program to test cattle for Bovine Spongiform Encephalopathy (BSE).
"The USDA has confirmed this animal did not enter the human food or animal feed supply.
"The bottom line for consumers remains the same: Your beef is safe. Experts in human and animal health agree that U.S. beef is safe from BSE because of the progressive steps taken by the U.S. government over the past two decades. The world's leading scientists, medical professionals and government officials agree that BSE is not a public or animal health risk in the United States.
"USDA is conducting an investigation to confirm the origin and age of this animal, though according to its media statement, 'the attending veterinarian has indicated that, based on dentition, it was an older animal, quite possibly upwards of 10 years of age.' This indicates that the animal would have been born prior to implementation of FDA's feed ban, which has proven to break the cycle of BSE.
"U.S. cattle producers do not anticipate this announcement to have an impact on our relationship with our international trading partners. The United States will continue to engage in trade that is consistent with the international standards outlined by the World Organization for Animal Health (OIE), and we expect countries that trade with us to do the same.
"USDA implemented its Enhanced BSE Surveillance Program more than two years ago and has tested, to date, 644,603 targeted animals at highest risk for BSE and has found only two positive cases, evidence that the prevalence of this disease in the United States is extremely low.
"As America's beef producers, our number-one priority has always been providing the safest beef in the world. Our livelihood depends on it, and that's why we have worked with the government and top scientists for more than 17 years to build, maintain and expand the BSE safeguards that today are protecting our cattle as well as your family and our own families."
Cattle Alert: NCBA Statement On Positive BSE Test Result
http://www.cattlenetwork.com/content.asp?contentid=22839
"The United States Department of Agriculture (USDA) confirmed this afternoon a positive test result as part of its enhanced surveillance program to test cattle for Bovine Spongiform Encephalopathy (BSE).
"The USDA has confirmed this animal did not enter the human food or animal feed supply.
"The bottom line for consumers remains the same: Your beef is safe. Experts in human and animal health agree that U.S. beef is safe from BSE because of the progressive steps taken by the U.S. government over the past two decades. The world's leading scientists, medical professionals and government officials agree that BSE is not a public or animal health risk in the United States.
"USDA is conducting an investigation to confirm the origin and age of this animal, though according to its media statement, 'the attending veterinarian has indicated that, based on dentition, it was an older animal, quite possibly upwards of 10 years of age.' This indicates that the animal would have been born prior to implementation of FDA's feed ban, which has proven to break the cycle of BSE.
"U.S. cattle producers do not anticipate this announcement to have an impact on our relationship with our international trading partners. The United States will continue to engage in trade that is consistent with the international standards outlined by the World Organization for Animal Health (OIE), and we expect countries that trade with us to do the same.
"USDA implemented its Enhanced BSE Surveillance Program more than two years ago and has tested, to date, 644,603 targeted animals at highest risk for BSE and has found only two positive cases, evidence that the prevalence of this disease in the United States is extremely low.
"As America's beef producers, our number-one priority has always been providing the safest beef in the world. Our livelihood depends on it, and that's why we have worked with the government and top scientists for more than 17 years to build, maintain and expand the BSE safeguards that today are protecting our cattle as well as your family and our own families."
OldDog/NewTricks
Well-known member
Most Have Read this but...
USDA Confirms BSE in Alabama Beef Animal
3/13/2006
AgWeb.com Editors
USDA today confirmed that the animal producing an inconclusive BSE test result via rapid testing over the weekend did test positive for BSE via the western blot test. The results of the immunohistochemistry test will be available later this week.
This marks the second case of BSE discovered in the United States during the enhanced surveillance program, officials said.
The animal was around 10 years of age and was found in Alabama, according to USDA Chief Veterinary Medical Officer John Clifford, and the animal was a beef breed -- Santa Gartrudis.
"The samples were taken from a non-ambulatory animal on a farm in Alabama," Clifford said in a statement. "A local private veterinarian euthanized and sampled the animal and sent the samples for further testing, which was conducted at one of our contract diagnostic laboratories at the University of Georgia. The animal was buried on the farm and it did not enter the animal or human food chains."
The animal resided less than a year on the farm in Alabama where it was discovered, Clifford said. It is not clear at this time whether the animal was U.S.- or Canadian-born. USDA will now conduct an epidemiological investigation relative to the situation, and they will be working to locate the birth cohorts and any offspring from the animal, Clifford noted. "We are now working with Alabama animal health officials to conduct an epidemiological investigation to gather any further information we can on the herd of origin of this animal," Clifford added.
USDA will also be working with the Food and Drug Administration (FDA) relative to feed issues, and given that it was 10 years old, Clifford said it would seem most likely that it was born prior to the feed bans relative to BSE protections being put in place.
While USDA said that it was highly unusual that there would be more than one animal in the herd that would have BSE, but Clifford promised to test all animals on the farm for BSE.
Clifford said they did not expect that the situation would impact efforts to restart trade with Japan and South Korea.
USDA Confirms BSE in Alabama Beef Animal
3/13/2006
AgWeb.com Editors
USDA today confirmed that the animal producing an inconclusive BSE test result via rapid testing over the weekend did test positive for BSE via the western blot test. The results of the immunohistochemistry test will be available later this week.
This marks the second case of BSE discovered in the United States during the enhanced surveillance program, officials said.
The animal was around 10 years of age and was found in Alabama, according to USDA Chief Veterinary Medical Officer John Clifford, and the animal was a beef breed -- Santa Gartrudis.
"The samples were taken from a non-ambulatory animal on a farm in Alabama," Clifford said in a statement. "A local private veterinarian euthanized and sampled the animal and sent the samples for further testing, which was conducted at one of our contract diagnostic laboratories at the University of Georgia. The animal was buried on the farm and it did not enter the animal or human food chains."
The animal resided less than a year on the farm in Alabama where it was discovered, Clifford said. It is not clear at this time whether the animal was U.S.- or Canadian-born. USDA will now conduct an epidemiological investigation relative to the situation, and they will be working to locate the birth cohorts and any offspring from the animal, Clifford noted. "We are now working with Alabama animal health officials to conduct an epidemiological investigation to gather any further information we can on the herd of origin of this animal," Clifford added.
USDA will also be working with the Food and Drug Administration (FDA) relative to feed issues, and given that it was 10 years old, Clifford said it would seem most likely that it was born prior to the feed bans relative to BSE protections being put in place.
While USDA said that it was highly unusual that there would be more than one animal in the herd that would have BSE, but Clifford promised to test all animals on the farm for BSE.
Clifford said they did not expect that the situation would impact efforts to restart trade with Japan and South Korea.
BSE UPDATE ALABAMA March 17, 2006
MONTGOMERY - Alabama Agriculture & Industries Commissioner Ron Sparks, State Veterinarian Dr. Tony Frazier, and Dr. Ken Angel with the USDA held a press conference today to answer questions about yesterday's exhumation of the remains of the cow that tested positive for BSE.
Federal and state agriculture workers excavated the remains of the animal, which had been buried on the farm and did not enter the animal or human food chain, in accordance with USDA protocols. The carcass was that of a red crossbred beef type cow. An examination of the cow's teeth confirmed that the animal was at least 10 years of age. Samples were taken of the animal and the remaining carcass was transported to one of the department's diagnostic labs for proper disposal. State and Federal staff are continuing the traceback to determine the herd of origin.
One calf was identified by the owner as belonging to the red cow. The calf is approximately 6 weeks old and appeared to be a healthy animal. The calf was transported to a USDA lab where DNA from the calf will be compared to that of the red cow to confirm relation. If confirmed, this would be the first offspring of a BSE diagnosed cow in the United States. Officials today learned that in early 2005 the BSE-positive cow gave birth to another black bull calf. This animal is in the process of being traced.
The cow was first examined by a local veterinarian in late February 2006. After the animal failed to respond to medical attention, it was humanely euthanized. The cattle producer buried the cow at the farm because Alabama Department of Agriculture & Industries regulations require burial of livestock within 24 hours. The producer did not suspect that the cow had BSE. The local veterinarian sent samples of the cow to the Alabama Department of Agriculture & Industries lab
system, which was then forwarded to the USDA lab in Athens, GA as part of the routine voluntary surveillance program for BSE testing. After the rapid test for BSE gave an inconclusive result, the samples were sent to Ames, Iowa for a Western Blot test, which gave a positive result. A third test, the immunohistochemistry (IHC) test, was performed this week and also returned positive results for BSE.
The Alabama Department of Agriculture and Industries and the USDA have been encouraging participation in Premises ID Registration as an important step in controlling animal disease. Since starting the program in 2005, over 2,000 premises have been registered in Alabama. For more information on Premises ID Registration call 334-240-7253
http://www.agi.state.al.us/press_releases/bse-update
http://www.agi.state.al.us/press_releases/bse-update?pn=2
ITEM 6 – BARB CASE CLUSTERS
39. Professor John Wilesmith (Defra) updated the committee on the
BSE cases born after the 1996 reinforced mammalian meat and
bone meal ban in the UK (BARB cases). Around 116 BARB cases
had been identified in Great Britain up to 22 November 2005,
mostly through active surveillance. BARB cases had decreased in
successive birth cohorts, from 44 in the 1996/1997 cohort to none
to date in the 2000/2001 cohort. However, 3 BARB cases had
been identified in the 2001/2002 cohort. Backcalculation of the
prevalence of BARB cases indicated a drop from 130 infected
animals per million (95% confidence interval 90-190) in the
1996/1997 cohort to 30 infected animals per million (95%
confidence interval 10-60) in the 1999/2000 cohort. A shift in the
geographical distribution of BSE cases, from the concentration of
pre-1996 BSE cases in Eastern England to a more uniform
14
© SEAC 2005
distribution of BARB cases, had occurred. However, it appeared
that certain post-1996 cohorts had a higher exposure to BSE in
certain areas for limited periods. Several clusters of BARB cases
within herds had been identified (5 pairs, 2 triplets and 1
quadruplet).
40. A triplet of BARB cases in South West Wales had been
investigated in detail. The triplet comprised 2 cases born in
September and October 2001 and a third in May 2002. The
animals born in 2001 were reared outdoors from the spring of 2002
but the animal born in 2002 had been reared indoors. Further
investigation of feeding practices revealed that a new feed bin for
the adult dairy herd had been installed in September 1998. In July
2002 the feed bin was emptied, but not cleaned, and relocated. All
3 BARB cases received feed from the relocated bin. This finding
suggested the hypothesis that the feed bin installed in September
1998 was filled initially with contaminated feed, that remnants of
this feed fell to the bottom of the bin during its relocation, and thus
young animals in the 2001/2002 birth cohort were exposed to
feedstuffs produced in 1998. No adult cattle had been infected
because of the reduced susceptibility to BSE with increasing age.
41. Further investigation of multiple case herds had found no
association of BARB clusters with the closure of feed mills.
42. Professor Wilesmith concluded that there is evidence of a decline
in risk of infection for successive birth cohorts of cattle. The BARB
epidemic is unlikely to be sustained by animals born after 31 July
2000. Feed bins could represent a continued source of occasional
infection and advice to farmers is being formulated to reduce this
risk. There is no evidence for an indigenous source of infection for
the BARB cases.
43. Members considered it encouraging that no other factor, apart from
feed contamination, had been identified as a possible cause of
BARB cases to date. Members commented that this study
suggests that only a small amount of contaminated feed may be
required for infection and that BSE infectivity can survive in the
environment for several years. Professor Wilesmith agreed and
noted that infection caused by small doses of infectious material
was consistent with other studies, and it would appear there is little
dilution of infectivity, if present, in the rendering system.
Additionally it appeared that the infectious agent had survived for 4
years in the feed bin.
44. The Chair thanked Professor Wilesmith for his presentation.
snip...
http://www.seac.gov.uk/minutes/final90.pdf
TSS
MONTGOMERY - Alabama Agriculture & Industries Commissioner Ron Sparks, State Veterinarian Dr. Tony Frazier, and Dr. Ken Angel with the USDA held a press conference today to answer questions about yesterday's exhumation of the remains of the cow that tested positive for BSE.
Federal and state agriculture workers excavated the remains of the animal, which had been buried on the farm and did not enter the animal or human food chain, in accordance with USDA protocols. The carcass was that of a red crossbred beef type cow. An examination of the cow's teeth confirmed that the animal was at least 10 years of age. Samples were taken of the animal and the remaining carcass was transported to one of the department's diagnostic labs for proper disposal. State and Federal staff are continuing the traceback to determine the herd of origin.
One calf was identified by the owner as belonging to the red cow. The calf is approximately 6 weeks old and appeared to be a healthy animal. The calf was transported to a USDA lab where DNA from the calf will be compared to that of the red cow to confirm relation. If confirmed, this would be the first offspring of a BSE diagnosed cow in the United States. Officials today learned that in early 2005 the BSE-positive cow gave birth to another black bull calf. This animal is in the process of being traced.
The cow was first examined by a local veterinarian in late February 2006. After the animal failed to respond to medical attention, it was humanely euthanized. The cattle producer buried the cow at the farm because Alabama Department of Agriculture & Industries regulations require burial of livestock within 24 hours. The producer did not suspect that the cow had BSE. The local veterinarian sent samples of the cow to the Alabama Department of Agriculture & Industries lab
system, which was then forwarded to the USDA lab in Athens, GA as part of the routine voluntary surveillance program for BSE testing. After the rapid test for BSE gave an inconclusive result, the samples were sent to Ames, Iowa for a Western Blot test, which gave a positive result. A third test, the immunohistochemistry (IHC) test, was performed this week and also returned positive results for BSE.
The Alabama Department of Agriculture and Industries and the USDA have been encouraging participation in Premises ID Registration as an important step in controlling animal disease. Since starting the program in 2005, over 2,000 premises have been registered in Alabama. For more information on Premises ID Registration call 334-240-7253
http://www.agi.state.al.us/press_releases/bse-update
http://www.agi.state.al.us/press_releases/bse-update?pn=2
ITEM 6 – BARB CASE CLUSTERS
39. Professor John Wilesmith (Defra) updated the committee on the
BSE cases born after the 1996 reinforced mammalian meat and
bone meal ban in the UK (BARB cases). Around 116 BARB cases
had been identified in Great Britain up to 22 November 2005,
mostly through active surveillance. BARB cases had decreased in
successive birth cohorts, from 44 in the 1996/1997 cohort to none
to date in the 2000/2001 cohort. However, 3 BARB cases had
been identified in the 2001/2002 cohort. Backcalculation of the
prevalence of BARB cases indicated a drop from 130 infected
animals per million (95% confidence interval 90-190) in the
1996/1997 cohort to 30 infected animals per million (95%
confidence interval 10-60) in the 1999/2000 cohort. A shift in the
geographical distribution of BSE cases, from the concentration of
pre-1996 BSE cases in Eastern England to a more uniform
14
© SEAC 2005
distribution of BARB cases, had occurred. However, it appeared
that certain post-1996 cohorts had a higher exposure to BSE in
certain areas for limited periods. Several clusters of BARB cases
within herds had been identified (5 pairs, 2 triplets and 1
quadruplet).
40. A triplet of BARB cases in South West Wales had been
investigated in detail. The triplet comprised 2 cases born in
September and October 2001 and a third in May 2002. The
animals born in 2001 were reared outdoors from the spring of 2002
but the animal born in 2002 had been reared indoors. Further
investigation of feeding practices revealed that a new feed bin for
the adult dairy herd had been installed in September 1998. In July
2002 the feed bin was emptied, but not cleaned, and relocated. All
3 BARB cases received feed from the relocated bin. This finding
suggested the hypothesis that the feed bin installed in September
1998 was filled initially with contaminated feed, that remnants of
this feed fell to the bottom of the bin during its relocation, and thus
young animals in the 2001/2002 birth cohort were exposed to
feedstuffs produced in 1998. No adult cattle had been infected
because of the reduced susceptibility to BSE with increasing age.
41. Further investigation of multiple case herds had found no
association of BARB clusters with the closure of feed mills.
42. Professor Wilesmith concluded that there is evidence of a decline
in risk of infection for successive birth cohorts of cattle. The BARB
epidemic is unlikely to be sustained by animals born after 31 July
2000. Feed bins could represent a continued source of occasional
infection and advice to farmers is being formulated to reduce this
risk. There is no evidence for an indigenous source of infection for
the BARB cases.
43. Members considered it encouraging that no other factor, apart from
feed contamination, had been identified as a possible cause of
BARB cases to date. Members commented that this study
suggests that only a small amount of contaminated feed may be
required for infection and that BSE infectivity can survive in the
environment for several years. Professor Wilesmith agreed and
noted that infection caused by small doses of infectious material
was consistent with other studies, and it would appear there is little
dilution of infectivity, if present, in the rendering system.
Additionally it appeared that the infectious agent had survived for 4
years in the feed bin.
44. The Chair thanked Professor Wilesmith for his presentation.
snip...
http://www.seac.gov.uk/minutes/final90.pdf
TSS