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From: TSS ()
Subject: USDA takes steps to battle CWD June 15, 2005
Date: June 5, 2005 at 7:58 pm PST

June 15, 2005 USDA takes steps to battle CWD

Chronic wasting disease survey and certification program in the works
The Department of Agriculture's Animal and Plant Health Inspection Service is seeking approval from the Office of Management and Budget to launch a national chronic wasting disease study and CWD herd certification program. The certification program and study are aimed at supporting the captive deer and elk industry in the United States and reducing CWD in captive herds. If the study and program are approved, participation will be voluntary.

Dr. Randy Pritchard, a veterinary medical officer with USDA-APHIS Veterinary Services who focuses on CWD, says he hopes the certification program and survey will be approved by fall 2005. "There is not a lot of information available for this industry," he said.

First detected in 1967, CWD has been found in members of the deer family, which include white-tailed deer, mule deer, and elk. To date, the disease has been identified in 13 states (see map) and two Canadian provinces.

In April, APHIS announced it was seeking OMB approval for a study that would collect information, through the National Animal Health Monitoring System, on the health and management practices of up to 5,600 cervid producers. "All indications are that it will be approved," Dr. Pritchard said.

If given the green light, the study will describe the farmed/captive cervid industry and identify the most efficient ways to contact producers for outreach purposes. In addition to other information, APHIS will track how long particular herds have been monitored for CWD.

"It is really important that people know that this is a voluntary study and that it is completely confidential," Dr. Pritchard said. "They won't be giving us any identification information. There will be no way to tie this back to an individual."

The agency will also use the collected information to prepare descriptive reports and information sheets that will be disseminated to cervid producers, stakeholders, academia, and other interested parties.

Dr. Pritchard says APHIS hopes to tie the survey to the national herd certification program, which is also awaiting approval from the OMB. The proposed rule on this certification program was published in the Federal Register on Dec. 24, 2003. "There were numerous comments from that, and it has taken awhile to sort through all of those," Dr. Pritchard said.

Dr. Dean Goeldner, APHIS CWD program coordinator, says that the agency has reviewed the comments and made some changes to the proposed rule. He says the final rule is still a few months away from being published.

Jurisdiction over captive deer and elk varies from state to state, and several states already enroll deer and elk herd owners in voluntary state certification programs. The proposed national herd certification program will recognize state programs that meet equivalent requirements, and allow cervid owners who reside in states without equivalent certification programs to directly enroll in the national certification program. The goal is to ensure that interstate movement of captive deer and elk does not spread CWD.

The national program will focus primarily on animal identification, regular CWD herd surveillance, testing of animals that die in monitored herds or are sent for slaughter, and limiting of new acquisitions to animals from herds that are also enrolled in the program. State and federal agencies will work together to trace the movements of animals with CWD and identify animals and herds that were exposed to them.

"I think this national program is very important, and the reason it is important is it would help standardize the approach taken by individuals states. It offers states a blueprint on which to build their programs," said Dr. William Hueston, director of the Center for Animal Health and Food Safety at the University of Minnesota. "It would really facilitate the whole interstate movement of these animals."

The proposed national program would not apply to animals being held for CWD research purposes, but to all other types of captive deer and elk. Most captive deer and elk are farmed, raised either for sale as meat, for sale as breeding animals, for harvest of antler velvet, or for hunting on private game facilities. A smaller number of captive deer and elk are maintained in zoos, other exhibitions, or research facilities.

Linking the CWD survey and herd certification program is commonsense, according to Dr. Pritchard. "The national certification program would be an ideal time to do this survey," he said. "Most of the time, the questionnaire is going to be administered by a field veterinarian, so our hope was that they would already be on the farm for the certification program."

Producers will be able to go through the certification process but skip the survey, if they so desire, and vice versa.

Although APHIS expects both the certification program and study to be given the go-ahead, it may move forward with the study if that is approved first. Staff at APHIS' CWD program have received a barrage of questions from the public, many of which they have not been able to answer because of a lack of data.

"We searched for answers to some of those questions and found out pretty quickly that those answers are not available, at least on an national level," Dr. Pritchard said. "We don't have a lot of knowledge about this industry."

Information collected through the survey should help.

–Kate O'Rourke

http://www.avma.org/onlnews/javma/jun05/050615d.asp


June 15, 2005

CWD found in New York wildlife
Chronic wasting disease, a transmissible encephalopathy, has been identified in two wild deer in Oneida County, New York. This news came shortly after the identification of five cases of CWD in farmed deer herds in the same county, which is located in the central part of the state (see JAVMA, May 15, 2005, page 1633). New York is the first state east of Illinois to have animals identified with the disease.

The wildlife cases were discovered through the New York State Department of Environmental Conservation's intensive monitoring efforts that were put into place after the disease was identified in captive herds.

In response to the wildlife cases, the DEC filed emergency regulations regarding the handling, transport, and management of deer in the state to prevent further spread of the disease in the wild. For example, the regulations prohibit the movement of certain animal parts out of a containment area established in and around Oneida County, and establish mandatory checkpoints for deer hunters in this area. They also include a number of provisions to be followed by individuals and facilities across the state. Implemented on April 29, the emergency regulations will be effective for 90 days. The DEC is in the process of developing permanent regulations.

At press time, the DEC, along with the Department of Agriculture's Wildlife Services program, had tested 317 wild deer in central New York as part of its investigation and had not identified any further cases of CWD in the wild. Investigators were still trying to determine the source or sources of the disease in the state. Since 2002, the DEC has collected more than 3,700 samples from wild white-tailed deer.

http://www.avma.org/onlnews/javma/jun05/050615p.asp

May 15, 2005
CWD found in New York
Disease makes first appearance in eastern United States; New York responds
Chronic wasting disease, a transmissible encephalopathy, has made its debut in farmed deer herds in the eastern United States. At press time, CWD had just been confirmed in five deer from two herds in Oneida County, New York. This is the first time the disease has been identified in any state east of Illinois.

Until now, CWD had been identified only in Colorado, Illinois, Kansas, Minnesota, Montana, Nebraska, New Mexico, Oklahoma, South Dakota, Utah, Wisconsin, and Wyoming. Saskatchewan and Alberta in Canada have also reported CWD infections. The disease has been found in captive animals in some states and provinces and in the wild in others. In some areas, the disease is found in both captive and wild animals.

Chronic wasting disease, first detected in 1967, has been found in members of the deer family, which include white-tailed deer, mule deer, and elk. Researchers hypothesize that prions, infectious proteins, cause the disease, but more research is needed into the fatal neurologic illness.

Responding to the positive cases in New York, Dr. William Hueston, director of the Center for Animal Health and Food Safety at the University of Minnesota, says he won't be surprised if the disease is found in additional states.

States that have experienced CWD have taken steps to regulate the movement of farmed deer and elk, but not all states have followed suit. The Department of Agriculture's Animal and Plant Health Inspection Service provides support for CWD prevention and surveillance for farmed and wild elk and deer as well as indemnification dollars for captive herds that must be destroyed. Many states, however, still struggle to fund state surveillance programs.

"The challenge is that most of the states are stretched very thin in their animal health resources," Dr. Hueston said. "Largely, legislators and legislatures have the attitude, which I perfectly understand, that if we don't have a problem, why should we pay for additional veterinary services or animal health programs? That is all well and good, as long as you don't get a new problem emerging."

The political climate is also a factor. "We are in an era where, in general, the majority of the people would like to see a smaller government and less laws, and that creates a window of opportunity for emerging diseases," Dr. Hueston said.

In New York, the responsibility for controlling CWD is shared by the USDA and two state departments. The Department of Environmental Conservation issues licenses to individuals who possess, import, or sell white-tailed deer, and also routinely tests New York's wild deer. The Department of Agriculture and Markets monitors the health and movement of all captive deer and elk for the presence of CWD. In July 2004, this department initiated the CWD Enhanced Surveillance and Monitoring Program. This program requires captive deer and elk herd owners to take various actions, including routine sampling and testing, animal identification, and an annual herd inventory.

On March 31, 2005, the NYSDAM announced they had confirmed the first case of CWD in the state. The animal, a six-year-old, white-tailed doe, was slaughtered from a captive herd as part of the state's mandatory surveillance. Preliminary tests performed at the New York State Veterinary Diagnostic Laboratory at Cornell University determined the presumptive positive, which was confirmed by the National Veterinary Services Laboratories in Ames, Iowa.

Nathan Rudgers, New York State commissioner of agriculture, said the identification demonstrated that the state control program is working. "Our control program achieves what it's intended to do, and that's to rapidly detect disease, if it's out there, and provide the proper protocols to quickly respond," he said.

The subsequent investigation revealed that one of the herds associated with the index animal had recently sent another sample to New York's veterinary diagnostic laboratory to be tested for CWD. The white-tailed deer had died from aspiration pneumonia, which is often associated with the disease. Because of the direct connection with the index herd, the department expedited the testing procedure by rerouting the sample to the NVSL, which announced the sample was positive.

The NYSDAM quarantined and depopulated the two herds in which the positive deer were found, and testing revealed three more deer with CWD from the index herd. Herds associated with the infected herds were also quarantined and, at press time, an investigation had been initiated to find and test any susceptible deer that came into contact with the index herd. Investigators were attempting to determine the source of the infection, and the NYSDEC was also conducting surveillance in surrounding wild deer populations.

The DEC is implementing precautionary regulations limiting transportation and possession of whole carcasses and some parts of wild deer taken near the location of the infected captive herds. The regulations will be similar to those currently in place for importation of carcasses and parts of deer into New York.

For the latest on the investigation, visit www.agmkt.state.ny.us/AI/cwd.html.

– Kate O'Rourke

http://www.avma.org/onlnews/javma/may05/050515h.asp


Greetings,

some studies worth noting...TSS


Title: Experimental Transmission of Chronic Wasting Disease (Cwd Mule Deer) Agent to Cattle by Intracerebral Route

Authors

Hamir, Amirali
Kunkle, Robert - bob
Cutlip, Randall - ARS RETIRED
Miller, Janice - ARS RETIRED
O'Rourke, Katherine
Williams, Elizabeth - UNIVERSITY OF WYOMING
Miller, Michael - COLORADO DIV WILDLIFE
Stack, Mick - VET SERVICES AGENCY, UK
Chaplin, Melanie - VET SERVICES AGENCY, UK
Richt, Juergen


Submitted to: Journal Of Veterinary Diagnostic Investigation
Publication Acceptance Date: January 3, 2005
Publication Date: N/A


Interpretive Summary: This communication reports final observations on experimental transmission of chronic wasting disease (CWD) from mule deer to cattle. Thirteen calves were inoculated into the brain with brain suspension from mule deer naturally affected with CWD. Three other calves were kept as uninoculated controls. The experiment was terminated 6 years post inoculation (PI). During that time, abnormal prion protein was demonstrated in the brain and spinal cord of 5 cattle by laboratory tests. However, consistent clinical signs and microscopic changes were not seen in any of these cattle. Age related changes were seen in both inoculated and control cattle. Findings of this study show that only 38% of the inoculated cattle were positive for CWD agent. Although inoculation directly into the brain is an unnatural route of exposure, and is the most severe challenge possible, this experiment shows that CWD transmission in cattle could have long incubation periods (up to 5 years). This finding suggests that oral exposure of cattle to CWD agent, a more natural potential route of exposure, would require not only a much larger dose of inoculum, but also, may not result in amplification of CWD agent within brain and spinal cord tissues during the normal lifespan of cattle. It is possible that a second bovine passage of material (cattle brain infected with CWD) from this study may result in a larger incidence of affected cattle with a shortened incubation time, and may produce different clinical and pathological findings. Such a study is now in progress. Also, experimental inoculations of cattle with CWD isolates from white-tailed deer and elk are needed to compare findings with the present study and these studies will be initiated in the near future. Impact: Results of this study show that although cattle inoculated directly into the brain with CWD succumb to the disease, the attack rate was rather small (38%) with this unnatural route of transmission. It is speculated that the oral route of infection may not result in replication of the agent during normal lifespan of cattle.
Technical Abstract: This communication reports final observations on experimental transmission of chronic wasting disease (CWD) from mule deer to cattle by the intracerebral route. Thirteen calves were inoculated intracerebrally with brain suspension from mule deer naturally affected with CWD. Three other calves were kept as uninoculated controls. The experiment was terminated 6 years post inoculation (PI). During that time, abnormal prion protein (PrPres) was demonstrated in the central nervous system (CNS) of 5 cattle by both immunohistochemistry (IHC) and Western blot (WB). However, microscopic lesions suggestive of spongiform encephalopathy in the brains of these PrPres positive animals were subtle in 3 cases and absent in 2 cases. The 3 uninoculated control cattle and 8 other inoculated animals euthanized during this time did not have PrPres in their CNS. Degenerative changes indicative of neuroaxonal dystrophy (NAD) were seen in dorsal medulla oblongata and appeared to be related to advancing age in both inoculated and control cattle. Analysis of the gene encoding bovine PRNP revealed homozygosity for alleles encoding 6 octapeptide repeats, serine (S) at codon 46 and S at codon 146 in all samples. Findings of this study show that although PrPres amplification occurred following direct inoculation into the brain, none of the affected animals had classic histopathologic lesions of spongiform encephalopathy. Furthermore, only 38% of the inoculated cattle demonstrated amplification of PrPres. Although intracerebral inoculation is an unnatural route of exposure, and is the most severe challenge possible, this experiment shows that CWD transmission in cattle could have long incubation periods (up to 5 years). This finding suggests that oral exposure of cattle to CWD agent, a more natural potential route of exposure, would require not only a much larger dose of inoculum, but also, may not result in amplification of PrPres within CNS tissues during the normal lifespan of cattle.


http://www.ars.usda.gov/research/publications/publications.htm?seq_no_115=166311


Perspective Title: Experimental Inoculation of Tme, Scrapie, and Cwd to Raccoons: An Update


Authors


Hamir, Amirali
Miller, Janice
Cutlip, Randall
Stack, Mick - VLA, WEYBRIDGE, UK
Chaplin, Melanie - VLA, WEYBRIDGE, UK
Bartz, J - CREIGHTON UNIVERSITY
Jenny, Al - USDA-APHIS-NVSL, AME
Williams, Elizabeth - UNIV WYOMING, LARAMIE


Submitted to: Wildlife Disease Association Annual Meeting
Publication Acceptance Date: August 11, 2003
Publication Date: August 11, 2003
Abstract only
Citation: Hamir, A.N., Miller, J.M., Cutlip, R.C., Stack, M., Chaplin, M., Bartz, J., Jenny, A., Williams, E. 2003. Experimental Inoculation Of Tme, Scrapie, And Cwd To Raccoons: An Update [abstract]. 52nd Annual Wildlife Disease Association Annual Meeting. P. 125.

Technical Abstract: Raccoons (Procyon lotor) are omnivorous and their diet may include carrion. It is therefore possible that in the wild they may get exposed to carcasses of animals with transmissible spongiform encephalopathies (TSEs). To determine the susceptibility of raccoons to transmissible mink encephalopathy (TME), scrapie, and chronic wasting disease (CWD), each of these agents was inoculated intracerebrally into a group of 4 kits. Three uninoculated kits served as controls. All raccoons in the TME-inoculated group developed neurologic signs and were euthanized within 6 months post inoculation (PI). In the scrapie-inoculated group, 3 animals became sick and were euthanized between 18 - 22 months PI. Although the fourth raccoon in this group did not show any clinical signs, it was euthanized at 24 months PI. At necropsy all clinically affected raccoons had extensive microscopic lesions of spongiform encephalopathy and protease-resistant prion protein (PrP**res) was detected in the CNS by immunohistochemistry and Western blot. In the CWD-inoculated group, 1 raccoon was euthanized at 39 months PI because of severe cystitis. Its brain was negative for PrP**res. At present, 4 years PI, the 3 remaining CWD-inoculated raccoons are alive and apparently healthy. These preliminary findings demonstrate that TME and scrapie can be transmitted to raccoons within 6 months and 2 years, respectively, whereas CWD cannot. Based on these incubation periods, it may be possible to differentiate these 3 TSEs should they occur in non-host species. Such a laboratory model would be relatively simple and inexpensive for characterization of unknown TSEs in the United States.


http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=148763

Title: Experimental Inoculation of Tme, Scrapie, and Cwd to Raccoons (Procyon Lotor) and the Unilization of Raccoons for Strain-Typing of Unknown Tses in the United States


Authors


Hamir, Amirali
Miller, Janice
Cutlip, Randall
Stack, Mick - VET LABS,WEYBRIDGE,UK
Chaplin, Melanie - VET LABS,WEYBRIDGE,UK
Bartz, J - CREIGHTON UNIVERSITY
Jenny, Allen - NVSL, APHIS, USDA
Williams, Elizabeth - UNIV WYOMING, LARAMIE


Submitted to: American Association Of Veterinary Laboratory Diagnosticians
Publication Acceptance Date: October 9, 2003
Publication Date: October 9, 2003
Abstract only
Citation: Hamir, A.N., Miller, J.M., Cutlip, R.C., Stack, M.J., Chaplin, M.J., Bartz, J., Jenny, A.L., Williams, E.S. 2003. Experimental Inoculation Of Tme, Scrapie, And Cwd To Raccoons (Procyon Lotor) And The Utilization Of Raccoons For Strain-Typing Of Unknown Tses In The United States [abstract]. 46th Annual Meeting Of The American Association Of Veterinary Laboratory Diagnosticians. P. 211.

Technical Abstract: Raccoons (Procyon lotor) are omnivorous and their diet may include carrion. It is therefore possible that in the wild they may get exposed to carcasses of animals with transmissible spongiform encephalopathies (TSEs). To determine the susceptibility of raccoons to transmissible mink encephalopathy (TME), scrapie, and chronic wasting disease (CWD), each of these agents was inoculated intracerebrally into a group of 4 kits. Three uninoculated kits served as controls. All raccoons in the TME-inoculated group developed neurologic signs and were euthanized within 6 months post inoculation (PI). In the scrapie-inoculated group, 3 animals became sick and were euthanized between 18 - 22 months PI. Although the fourth raccoon in this group did not show any clinical signs, it was euthanized at 24 months PI. At necropsy all clinically affected raccoons had extensive microscopic lesions of spongiform encephalopathy and protease-resistant prion protein (PrP**res) was detected in the CNS by immunohistochemistry and Western blot. In the CWD-inoculated group, 1 raccoon was euthanized at 39 months PI because of severe cystitis. Its brain was negative for PrP**res. At present, 4 years PI, the 3 remaining CWD-inoculated raccoons are alive and apparently healthy. These preliminary findings demonstrate that TME and scrapie can be transmitted to raccoons within 6 months and 2 years, respectively, whereas CWD cannot. Based on these incubation periods, it may be possible to differentiate these 3 TSEs should they occur in non-host species. Such a laboratory model would be relatively simple and inexpensive for characterization of unknown TSEs in the United States.


http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=149097


Title: Experimental Cross-Species Transmission of Chronic Wasting Disease (Cwd) at the National Animal Disease Center (Nadc), Ames, Iowa: An Update

Author

Hamir, Amirali


Submitted to: Meeting Abstract
Publication Acceptance Date: September 29, 2004
Publication Date: N/A


Technical Abstract: Experimental cross-species transmission of transmissible spongiform encephalopathies (TSEs) provides valuable information for identification of potential host ranges, and generates much needed prion-infected tissues for research. At NADC, studies utilizing CWD agent(s) were initiated in 1997. However, since these studies involve long incubation periods under BL-2 conditions, to date only one study has been completed. Initially our studies were restricted to farm livestock (cattle and sheep). However, as a result of increased demand from our stakeholders, we now also conduct research on wildlife (herbivores and carnivores). Following are some of the significant findings of past and on-going experiments at NADC: Completed study: CATTLE: Intracerebral inoculation of CWD-mule-deer resulted in amplification of PrPres in a small number of inoculated cattle (5 of 13; 38%). However, none of the animals with PrPres had classic histopathologic lesions of spongiform encephalopathy. Studies utilizing CWD-elk and CWD-white-tailed-deer in cattle are in progress. Preliminary findings of ongoing CWD experiments in other species indicate that: 1. SHEEP: CWD-mule-deer can be transmitted intracerebrally to sheep (1 of 8; 5 yrs PI). 2. WHITE-TAILED DEER: CWD-elk, CWD-white-tailed-deer, and CWD-mule-deer are pathogenic for white-tailed deer (60%; 2 yrs PI). 3. FALLOW DEER: Compared with other cervids studies, appear to be resistant to intracerebral inoculation of CWD-elk and CWD-white-tailed-deer (0%; 2 yrs PI). White-tailed deer with CWD-mule-deer are pending. 4. RACCOONS: TME and scrapie can be transmitted within 6 months and 2 years, respectively, whereas CWD cannot. (Therefore, may be possible to differentiate these 3 TSE agents in raccoons). Study utilizing BSE in raccoons is pending.


http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=167763


-------- Original Message -------- Subject: Re: CWD TO CATTLE by inoculation (ok,is it three or four OR NOW FIVE???)
Date: Mon, 23 Jun 2003 17:12:38 -0500
From: "Terry S. Singeltary Sr."
Reply-To: Bovine Spongiform Encephalopathy
To: BSE-L@uni-karlsruhe.de
References: sef6f471.006@nadcgw.nadc.ars.usda.gov


######## Bovine Spongiform Encephalopathy #########

hello Dr. Miller,

thank you so much for this update!


indistinguishable from scrapie


what do you conclude from this?

if CWD transmits to sheep, and it is;

''indistinguishable from scrapie''

then what do we have here?

if CWD transmits to sheep and is the same
as Scrapie, then what about BSE to sheep
being indistinguishable from scrapie?

those Vermont sheep are looking more and more
interesting, anything from that yet?

what a mess!

i don't mean for this to be a trick question,
just trying to figure this out...

this is more fuel for the fire to rapid TSE test
1 million USA cattle annually for 5 years, especially
in areas of high concentration of CWD, and ban all MMBM,
SRMS, MRMs, and stunning ASAP (in my opinion)...

thank you,
kindest regards,
terry


Janice M. Miller wrote:


######## Bovine Spongiform Encephalopathy #########

I am happy to provide an update on the experimental inoculation of
cattle and sheep with CWD. These are ongoing experiments and updates
are normally provided via presentations at meetings. Dr. Hamir has
prepared a poster of the following information that will be displayed at
4 upcoming meetings this summer and fall.

Experimental Transmission of Chronic Wasting Disease (CWD) to Cattle
and Sheep
Progress report - June 23, 2003

Experimental Transmission to Cattle

Background:
In 1997, 13 calves were inoculated intracerebrally with brain
suspension from mule deer naturally affected with CWD. During the first
3 years, 3 animals were euthanized 23, 24, and 28 months after
inoculation because of weight loss (2) or sudden death (1). Although
microscopic examination of the brains did not show classical lesions of
transmissible spongiform encephalopathy (TSE), a specific TSE marker
protein, PrPres, was detected by immunohistochemistry (IHC) and western
blot. Detailed information on these animals has been published
previously (A Hamir et al., J Vet Diagn Invest 13: 91-96, 2001).

Update:
During the 3rd, 4th and 6th years of observation, 7 additional animals
have been euthanized due to a variety of health concerns (primarily
chronic joint and foot problems). IHC and western blot results indicate
that 2 of these animals, necropsied 59 and 63 months after inoculation,
were positive for PrPres. One animal (# 1746) had not been eating well
for approximately 1 week prior to being found recumbent. At necropsy,
significant gross lesions consisted of an oblique fracture of L1
vertebral arch with extension into the body, and moderate multifocal
hemorrhagic ulceration in the abomasum. Microscopic examination of
brain revealed a few isolated neurons with single or multiple vacuoles,
but neither neuronal degeneration nor gliosis was observed. IHC
revealed the presence of PrPres in sections from several areas of the
brain. The other PrPres positive animal (#1742) was euthanized after
being found in lateral recumbency with a body temperature of 104.6 F.
It had not shown prior clinical signs except for some decreased appetite
for 2 days. Necropsy revealed only moderate hepatitis and a small renal
infarct due to intravascular thrombosis.

Summary of findings on all necropsied animals to date:

Ear tag Date of Survival Disease Clinical
Histo- IHC WB
no. necropsy period course signs
pathology
_____________________________________________________________________
1745 8/18/99 23m 2m +
± + +
1768 9/22/99 24m 3m +
± + +
1744 1/29/00 28m 3d ±
- + +
1749 5/20/01 44m NA -
- - -
1748 6/27/01 45m NA -
- - -
1743 8/21/02 59m NA -
- - -
1741 8/22/02 59m NA -
- - -
1746 8/27/02 59m 7d ±
± + +
1765 11/27/02 62m 1d ±
± - -
1742 12/28/02 63m 2d ±
- + +
NT = not tested; IHC = immunohistochemistry for PrPres; SAF = scrapie
associated fibrils; NA = not applicable; WB = Western blot
(Prionics-Check); + = lesions or antigen present; - = lesions or
antigen absent; ± = signs/lesions equivocal; i/c = intracerebral; m =
months; d = days.

Summary:
After 5.75 years of observation we have 5 CWD transmissions to cattle
from a group of 13 inoculates. These animals, which were necropsied 23,
24, 28, 59, and 63 months after inoculation, did not show the clinical
signs or histopathologic lesions typical of a TSE, but PrPres was
detected in brain samples by both immunohistochemistry and western blot.
Five other animals necropsied during the 4th, 5th and 6th years of
observation have not shown evidence of PrPres and the remaining 3 cattle
are apparently healthy. Note that this study involved direct
intracerebral inoculation of cattle with the CWD agent, which is an
unnatural route of exposure. Likely, it would be more difficult to
infect cattle by the oral route. Cattle have been inoculated orally at
the University of Wyoming with the same inoculum used in this
experiment, and 5.75 years into the study the animals remain healthy
(personal communication, Dr. Beth Williams).

Experimental Transmission of CWD to sheep

Eight Suffolk sheep from the NADC scrapie-free flock were inoculated
intracerebrally with the CWD brain suspension used to inoculate cattle.
PRNP genotyping showed that 4 of the sheep were QQ at codon 171 and the
other four were QR. Two of the QQ sheep were euthanized during the 3rd
year of observation. At necropsy one of these animals had a urethral
obstruction and PrPres was not detected in brain or lymphoid tissues.
The other sheep, necropsied 35 months after inoculation, showed clinical
signs and histopathologic lesions that were indistinguishable from
scrapie. IHC tests showed typical PrPres accumulations in brain,
tonsil, and some lymph nodes. The 2 remaining QQ sheep and all 4 QR
sheep are apparently healthy 47 months after inoculation.

Summary:
After 4 years of observation we have 1 transmission of CWD to a 171 QQ
sheep. This animal, which was necropsied 35 months after inoculation,
showed clinical signs and histopathologic lesions that were
indistinguishable from scrapie. Another QQ sheep that was necropsied
during the 3rd year showed no evidence of prion disease and all
remaining sheep (2 QQ and 4 QR) are apparently healthy.

########### http://mailhost.rz.uni-karlsruhe.de/warc/bse-l.html ############


########### http://mailhost.rz.uni-karlsruhe.de/warc/bse-l.html ############



Oral transmission and early lymphoid tropism of chronic wasting disease PrPres in mule deer fawns (Odocoileus hemionus )
Christina J. Sigurdson1, Elizabeth S. Williams2, Michael W. Miller3, Terry R. Spraker1,4, Katherine I. O'Rourke5 and Edward A. Hoover1

Department of Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523- 1671, USA1
Department of Veterinary Sciences, University of Wyoming, 1174 Snowy Range Road, University of Wyoming, Laramie, WY 82070, USA 2
Colorado Division of Wildlife, Wildlife Research Center, 317 West Prospect Road, Fort Collins, CO 80526-2097, USA3
Colorado State University Veterinary Diagnostic Laboratory, 300 West Drake Road, Fort Collins, CO 80523-1671, USA4
Animal Disease Research Unit, Agricultural Research Service, US Department of Agriculture, 337 Bustad Hall, Washington State University, Pullman, WA 99164-7030, USA5


Author for correspondence: Edward Hoover.Fax +1 970 491 0523. e-mail ehoover@lamar.colostate.edu


Abstract



Mule deer fawns (Odocoileus hemionus) were inoculated orally with a brain homogenate prepared from mule deer with naturally occurring chronic wasting disease (CWD), a prion-induced transmissible spongiform encephalopathy. Fawns were necropsied and examined for PrP res, the abnormal prion protein isoform, at 10, 42, 53, 77, 78 and 80 days post-inoculation (p.i.) using an immunohistochemistry assay modified to enhance sensitivity. PrPres was detected in alimentary-tract-associated lymphoid tissues (one or more of the following: retropharyngeal lymph node, tonsil, Peyer's patch and ileocaecal lymph node) as early as 42 days p.i. and in all fawns examined thereafter (53 to 80 days p.i.). No PrPres staining was detected in lymphoid tissue of three control fawns receiving a control brain inoculum, nor was PrPres detectable in neural tissue of any fawn. PrPres-specific staining was markedly enhanced by sequential tissue treatment with formic acid, proteinase K and hydrated autoclaving prior to immunohistochemical staining with monoclonal antibody F89/160.1.5. These results indicate that CWD PrP res can be detected in lymphoid tissues draining the alimentary tract within a few weeks after oral exposure to infectious prions and may reflect the initial pathway of CWD infection in deer. The rapid infection of deer fawns following exposure by the most plausible natural route is consistent with the efficient horizontal transmission of CWD in nature and enables accelerated studies of transmission and pathogenesis in the native species.


snip...


Oral exposure is the most plausible pathway by which the CWD prion may be introduced to deer in nature. Consequently, we chose this means of inoculation in an attempt to demonstrate the feasibility of CWD transmission by this route and to study early lymphoid tissue tropism of the PrPres in deer. Each deer was repeatedly exposed to a known infectious CWD inoculum over a 5-day-period because recent results with scrapie in hamsters indicate repeated oral exposure increases the incidence of infection (Diringer et al., 1998 ). Because mice are relatively resistant to CWD (M. Bruce, personal communication) precluding bioassay, and because several studies have shown that PrPres strongly correlates with disease (McKinley et al., 1983 ; Race et al. , 1998 ), we employed an enhanced immunostaining method (formic acid, proteinase K and hydrated autoclaving) to detect PrPres in situ. Formic acid and hydrated autoclaving have been previously described for PrPres epitope exposure prior to immunohistochemistry (IHC) (Miller et al., 1994 ; van Keulen et al., 1995 ). Using these methods, we demonstrate PrPres in regional lymph nodes as early as 6 weeks after oral exposure of deer fawns to the CWD agent.


snip...


Discussion




These results indicate that mule deer fawns develop detectable PrP res after oral exposure to an inoculum containing CWD prions. In the earliest post-exposure period, CWD PrPres was traced to the lymphoid tissues draining the oral and intestinal mucosa (i.e. the retropharyngeal lymph nodes, tonsil, ileal Peyer's patches and ileocaecal lymph nodes), which probably received the highest initial exposure to the inoculum. Hadlow et al. (1982) demonstrated scrapie agent in the tonsil, retropharyngeal and mesenteric lymph nodes, ileum and spleen in a 10-month-old naturally infected lamb by mouse bioassay. Eight of nine sheep had infectivity in the retropharyngeal lymph node. He concluded that the tissue distribution suggested primary infection via the gastrointestinal tract. The tissue distribution of PrPres in the early stages of infection in the fawns is strikingly similar to that seen in naturally infected sheep with scrapie. These findings support oral exposure as a natural route of CWD infection in deer and support oral inoculation as a reasonable exposure route for experimental studies of CWD.

snip...

full text;

http://vir.sgmjournals.org/cgi/content/full/80/10/2757?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&titleabstract=Oral+Transmission+And+Early+Lymphoid+Tropism+Of+Chronic+Wasting+Disease&fulltext=Oral+Transmission+And+Early+Lymphoid+Tropism+Of+Chronic+Wasting+Disease&searchid=1056118413058_454&stored_search=&FIRSTINDEX=0&search_url=http%3A%2F%2Fvir.sgmjournals.org%2Fcgi%2Fsearch&journalcode=vir

Oral transmission of kuru, Creutzfeldt-Jakob disease, and scrapie to
nonhuman primates.

Gibbs CJ Jr, Amyx HL, Bacote A, Masters CL, Gajdusek DC.

Kuru and Creutzfeldt-Jakob disease of humans and scrapie disease of
sheep and goats were transmitted to squirrel monkeys (Saimiri sciureus)
that were exposed to the infectious agents only by their nonforced
consumption of known infectious tissues. The asymptomatic incubation
period in the one monkey exposed to the virus of kuru was 36 months;
that in the two monkeys exposed to the virus of Creutzfeldt-Jakob
disease was 23 and 27 months, respectively; and that in the two monkeys
exposed to the virus of scrapie was 25 and 32 months, respectively.
Careful physical examination of the buccal cavities of all of the
monkeys failed to reveal signs or oral lesions. One additional monkey
similarly exposed to kuru has remained asymptomatic during the 39 months
that it has been under observation.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6997404&dopt=Abstract


1: Dev Biol Stand 1993;80:9-13

Transmission of human spongiform encephalopathies to experimental
animals: comparison of the chimpanzee and squirrel monkey.

Asher DM, Gibbs CJ Jr, Sulima MP, Bacote A, Amyx H, Gajdusek DC.

Laboratory of Central Nervous System Studies, National Institute of
Neurological Disorders and Stroke, NIH, Bethesda, MD 20992.

The agents of kuru and Creutzfeldt-Jakob disease have been consistently
transmitted from patients with those diseases to chimpanzees and
squirrel monkeys, as well as to other new-world primates, with average
incubation periods of two or three years. No other animals have been
found so consistently susceptible to the agents in human tissues. More
rapid and convenient assays for the infectious agents would greatly
facilitate research on the spongiform encephalopathies of humans.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8270119&dopt=Abstract

Aguzzi warns of CWD danger

The TSE family of diseases also includes chronic wasting disease (CWD)
in deer, a condition that has spread in the US in recent years (Nature
416, 569; 2002). Speaking at the Days of Molecular Medicine conference
in La Jolla in March, prion expert Adriano Aguzzi issued a strong
warning against underestimating this form of TSE.

"For more than a decade, the US has by-and-large considered mad cows
to be an exquisitely European problem. The perceived need to protect
US citizens from this alien threat has even prompted the deferral of
blood donors from Europe," he said. "Yet the threat-from-within
posed by CWD needs careful consideration, since the evidence that CWD
is less dangerous to humans than BSE is less-than-complete. Aguzzi
went on to point out that CWD is arguably the most mysterious of all
prion diseases.

"Its horizontal spread among the wild population is exceedingly
efficient, and appears to have reached a prevalence unprecedented even
by BSE in the UK at its peak. The pathogenesis of CWD, therefore,
deserves a vigorous research effort. Europeans also need to think
about this problem, and it would be timely and appropriate to increase
CWD surveillance in Europe too." Aguzzi has secured funding from the
National Institutes of Health to investigate CWD, and the effort will
be lead by Christina Sigurdson in his department at the University of
Zurich. KAREN BIRMINGHAM, LONDON

This quote from Dr. Gambetti is especially significant since he is the
rather cautious TSE researcher under contract with the Centers for Disease
Control to examine the brains of individuals who have died of CJD.
-----------------

Pierluigi Gambetti, director of the National Prion Disease Pathology
Surveillance Center at Case Western Reserve University in Cleveland,
said all deer should be tested for chronic wasting disease before any
processing is done.

"There is no way around it," he said. "Nobody should touch that meat
unless it has been tested."
--------------------------------------

http://www.ledger-enquirer.com/mld/...ion/3954298.htm

SEWING THE SEEDS OF MAD COW (CWD) THROUGH ANIMAL PROTEIN $

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DEPARTMENT OF HEALTH & HUMAN SERVICES PUBLIC HEALTH SERVICE FOOD AND DRUG ADMINISTRATION

April 9, 2001 WARNING LETTER

01-PHI-12 CERTIFIED MAIL RETURN RECEIPT REQUESTED

Brian J. Raymond, Owner Sandy Lake Mills 26 Mill Street P.O. Box 117 Sandy Lake, PA 16145 PHILADELPHIA DISTRICT

Tel: 215-597-4390

Dear Mr. Raymond:

Food and Drug Administration Investigator Gregory E. Beichner conducted an inspection of your animal feed manufacturing operation, located in Sandy Lake, Pennsylvania, on March 23, 2001, and determined that your firm manufactures animal feeds including feeds containing prohibited materials. The inspection found significant deviations from the requirements set forth in Title 21, code of Federal Regulations, part 589.2000 - Animal Proteins Prohibited in Ruminant Feed. The regulation is intended to prevent the establishment and amplification of Bovine Spongiform Encephalopathy (BSE) . Such deviations cause products being manufactured at this facility to be misbranded within the meaning of Section 403(f), of the Federal Food, Drug, and Cosmetic Act (the Act).

Our investigation found failure to label your swine feed with the required cautionary statement "Do Not Feed to cattle or other Ruminants" The FDA suggests that the statement be distinguished by different type-size or color or other means of highlighting the statement so that it is easily noticed by a purchaser.

In addition, we note that you are using approximately 140 pounds of cracked corn to flush your mixer used in the manufacture of animal feeds containing prohibited material. This flushed material is fed to wild game including deer, a ruminant animal. Feed material which may potentially contain prohibited material should not be fed to ruminant animals which may become part of the food chain.

The above is not intended to be an all-inclusive list of deviations from the regulations. As a manufacturer of materials intended for animal feed use, you are responsible for assuring that your overall operation and the products you manufacture and distribute are in compliance with the law. We have enclosed a copy of FDA's Small Entity Compliance Guide to assist you with complying with the regulation... blah, blah, blah...

http://www.fda.gov/foi/warning_letters/g1115d.pdf


Chronic Wasting Disease and Potential Transmission to Humans
Ermias D. Belay,* Ryan A. Maddox,* Elizabeth S. Williams,† Michael W. Miller,‡ Pierluigi Gambetti,§ and Lawrence B. Schonberger*
*Centers for Disease Control and Prevention, Atlanta, Georgia, USA; †University of Wyoming, Laramie, Wyoming, USA; ‡Colorado Division of Wildlife, Fort Collins, Colorado, USA; and §Case Western Reserve University, Cleveland, Ohio, USA

Suggested citation for this article: Belay ED, Maddox RA, Williams ES, Miller MW, Gambetti P, Schonberger LB. Chronic wasting disease and potential transmission to humans. Emerg Infect Dis [serial on the Internet]. 2004 Jun [date cited]. Available from: http://www.cdc.gov/ncidod/EID/vol10no6/03-1082.htm


--------------------------------------------------------------------------------

Chronic wasting disease (CWD) of deer and elk is endemic in a tri-corner area of Colorado, Wyoming, and Nebraska, and new foci of CWD have been detected in other parts of the United States. Although detection in some areas may be related to increased surveillance, introduction of CWD due to translocation or natural migration of animals may account for some new foci of infection. Increasing spread of CWD has raised concerns about the potential for increasing human exposure to the CWD agent. The foodborne transmission of bovine spongiform encephalopathy to humans indicates that the species barrier may not completely protect humans from animal prion diseases. Conversion of human prion protein by CWD-associated prions has been demonstrated in an in vitro cell-free experiment, but limited investigations have not identified strong evidence for CWD transmission to humans. More epidemiologic and laboratory studies are needed to monitor the possibility of such transmissions.


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Risk for Transmission to Humans
Epidemiologic Studies
The increasing detection of CWD in a wider geographic area and the presumed foodborne transmission of BSE to humans, resulting in cases of vCJD, have raised concerns about the possible zoonotic transmission of CWD (32). In the late 1990s, such concerns were heightened by the occurrence of CJD among three patients 30 years of age who were deer hunters or ate deer and elk meat harvested by family members (Table 2). However, epidemiologic and laboratory investigations of these case-patients indicated no strong evidence for a causal link between CWD and their CJD illness (33). None of the patients were reported to have hunted deer or eaten deer meat harvested in the CWD-endemic areas of Colorado and Wyoming. Such a history in unusually young CJD patients, if present, would have supported a causal link with CWD. Moreover, the testing of brain tissues from >1,000 deer and elk harvested from areas where the patients hunted or their venison originated did not show any evidence of CWD (33). In addition, the lack of homogeneity in the clinicopathologic manifestation and codon 129 of the prion protein gene among the three patients suggested that their illnesses could not be explained by exposure to the same prion strain. In vCJD, homogeneity of the genotype at codon 129 and the clinical and pathologic phenotype were attributed to the patients' exposure to the same prion strain, the agent of BSE.

In 2001, the case of a 25-year-old man who reportedly died of a prion disease after an illness lasting ≈22 months was investigated (Table 2). Although this man had hunted deer only rarely, his grandfather hunted deer and elk throughout much of the 1980s and 1990s and regularly shared the venison with the case-patient's family. The grandfather primarily hunted in southeastern Wyoming, around the known CWD-endemic area. The case-patient's illness began with a seizure and progressed to fatigue, poor concentration, and depression. Memory loss, ataxia, speech abnormalities, combative behavior, and recurrent seizures also developed. Histopathologic, immunohistochemical, and Western blot testing of brain autopsy samples confirmed a prion disease diagnosis. Analysis of the prion protein gene indicated a P102L mutation coupled with valine at the polymorphic codon 129 in the mutant allele, confirming a diagnosis of Gerstmann-Sträussler-Scheinker syndrome (GSS). This case-patient was unusually young even for a person with a GSS P102L mutation. It remains unknown whether the possible exposure of the case-patient to CWD-infected venison potentially contributed to the early onset of his prion disease.

In 2001, two additional CJD patients 26 and 28 years of age were reported from a single state (Table 2) (34). The patients grew up in adjacent counties and had illness onset within several months of each other. As a result of this fact and their unusually young age, a possible environmental source of infection, including exposure to CWD-infected venison, was considered. One of the patients died after an illness lasting 5–6 months that was characterized by progressive aphasia, memory loss, social withdrawal, vision disturbances, and seizure activity leading to status epilepticus and induced coma. Histopathologic, immunohistochemical, and Western blot testing of brain biopsy and autopsy samples confirmed a CJD diagnosis. The patient's disease phenotype corresponded to the MM2 sporadic CJD subtype reported by Parchi et al. (35). This patient did not hunt, and family members provided no history of regularly eating venison. The patient may have occasionally eaten venison originating from the Upper Peninsula of Michigan while away from home during his college years. However, ongoing surveillance has not detected CWD in Michigan deer (36).

The second patient died from an illness lasting <16 months. The patient's illness began with behavioral changes, including unusual outbursts of anger and depression. Confusion, memory loss, gait disturbances, incontinence, headaches, and photophobia also developed. Western blot analysis of frozen brain biopsy tissue confirmed a prion disease diagnosis. Immunohistochemical analysis of brain tissue obtained after the patient's death showed prion deposition consistent with GSS. A prion protein gene analysis could not be performed because appropriate samples were lacking. However, prion protein gene analysis of a blood sample from one of the patient's parents indicated a GSS P102L mutation. The patient did not hunt but may have eaten venison from Michigan once when he was 1–2 years old. The GSS diagnosis greatly reduced the likelihood that the two patients reported from adjacent counties had disease with a common origin.

Recently, rare neurologic disorders resulting in the deaths of three men who participated in "wild game feasts" in a cabin owned by one of the decedents created concern about the possible relationship of their illnesses with CWD (Table 2) (37). Two of the patients reportedly died of CJD, and the third died from Pick's disease. More than 50 persons were identified as possibly participating in these feasts; the three patients were the only participants reported to have died of a degenerative neurologic disorder. Reanalysis of autopsy brain tissues from the three patients at the National Prion Disease Pathology Surveillance Center indicated that two of them had no evidence of a prion disease by immunohistochemical analysis. CJD was confirmed in the third patient, who had clinicopathologic, codon 129, and prion characteristics similar to the most common sporadic CJD subtype (MM1/MV1) (35). This patient participated in the feasts only once, perhaps in the mid-1980s. In addition, the investigation found no evidence that the deer and elk meat served during the feasts originated from the known CWD-endemic areas of Colorado and Wyoming.

In 2003, CJD in two deer and elk hunters (54 and 66 years of age) was reported (38). The report implied that the patients had striking neuropathologic similarities and that their illness may represent a new entity in the spectrum of prion diseases. A third patient (63 years of age), who was also purported to have been a big game hunter, was subsequently reported from the same area. However, none of the three patients were reported to have eaten venison from the CWD-endemic areas of the western United States. The 66-year-old patient hunted most of his life in Washington State. Although information about the 54-year-old patient was limited, there was no evidence that he hunted in CWD-endemic areas. The third patient was not a hunter but ate venison harvested from Pennsylvania and Washington. The neuropathologic changes, Western blot profile, and genotype at codon 129 of the three patients each fit the MM1, VV1, or VV2 sporadic CJD subtype, indicating absence of phenotypic similarity among the cases or atypical neuropathologic features (35).

To date, only two nonfamilial CJD cases with a positive history of exposure to venison obtained from the known CWD-endemic areas have been reported. One of the patients was a 61-year-old woman who grew up in an area where this disease is known to be endemic, and she ate venison harvested locally. She died in 2000, and analysis of autopsy brain specimens confirmed that the patient's CJD phenotype fit the MM1 subtype, with no atypical neuropathologic features. The second patient was a 66-year-old man who was reported to have eaten venison from two deer harvested in a CWD-endemic area. Both deer tested negative for CWD, and the patient's illness was consistent with the MM1 CJD phenotype.

Despite the decades-long endemicity of CWD in Colorado and Wyoming, the incidence of CJD and the age distribution of CJD case-patients in these two states are similar to those seen in other parts of the United States. From 1979 to 2000, 67 CJD cases from Colorado and 7 from Wyoming were reported to the national multiple cause-of-death database. The average annual age-adjusted CJD death rate was 1.2 per million persons in Colorado and 0.8 in Wyoming. The proportion of CJD patients who died before age 55 in Colorado (13.4%) was similar to that of the national (10.2%). The only CJD case-patient <30 years of age in Colorado had iatrogenic CJD linked to receipt of human growth hormone injections. CJD was not reported in persons <55 years of age in Wyoming during the 22-year surveillance period.

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Conclusions
The lack of evidence of a link between CWD transmission and unusual cases of CJD, despite several epidemiologic investigations, and the absence of an increase in CJD incidence in Colorado and Wyoming suggest that the risk, if any, of transmission of CWD to humans is low. Although the in vitro studies indicating inefficient conversion of human prion protein by CWD-associated prions raise the possibility of low-level transmission of CWD to humans, no human cases of prion disease with strong evidence of a link with CWD have been identified. However, the transmission of BSE to humans and the resulting vCJD indicate that, provided sufficient exposure, the species barrier may not completely protect humans from animal prion diseases. Because CWD has occurred in a limited geographic area for decades, an adequate number of people may not have been exposed to the CWD agent to result in a clinically recognizable human disease. The level and frequency of human exposure to the CWD agent may increase with the spread of CWD in the United States. Because the number of studies seeking evidence for CWD transmission to humans is limited, more epidemiologic and laboratory studies should be conducted to monitor the possibility of such transmissions. Studies involving transgenic mice expressing human and cervid prion protein are in progress to further assess the potential for the CWD agent to cause human disease. Epidemiologic studies have also been initiated to identify human cases of prion disease among persons with an increased risk for exposure to potentially CWD-infected deer or elk meat (47). If such cases are identified, laboratory data showing similarities of the etiologic agent to that of the CWD agent would strengthen the conclusion for a causal link. Surveillance for human prion diseases, particularly in areas where CWD has been detected, remains important to effectively monitor the possible transmission of CWD to humans. Because of the long incubation period associated with prion diseases, convincing negative results from epidemiologic and experimental laboratory studies would likely require years of follow-up. In the meantime, to minimize the risk for exposure to the CWD agent, hunters should consult with their state wildlife agencies to identify areas where CWD occurs and continue to follow advice provided by public health and wildlife agencies. Hunters should avoid eating meat from deer and elk that look sick or test positive for CWD. They should wear gloves when field-dressing carcasses, bone-out the meat from the animal, and minimize handling of brain and spinal cord tissues. As a precaution, hunters should avoid eating deer and elk tissues known to harbor the CWD agent (e.g., brain, spinal cord, eyes, spleen, tonsils, lymph nodes) from areas where CWD has been identified.

Acknowledgments
snip...END

http://www.cdc.gov/ncidod/EID/vol10no6/03-1082.htm


SEAC Statement
18th January 2005

--------------------------------------------------------------------------------

Position statement - Chronic wasting disease in UK deer
Introduction

1. The Food Standards Agency asked SEAC to consider the possible public and animal health implications of chronic wasting disease (CWD), in particular the level of risk posed to consumers of meat from infected animals. The committee also considered the possibility that BSE may be present in UK deer.

Background

2. CWD has emerged as an endemic transmissible spongiform encephalopathy (TSE) in certain captive and free-ranging species of cervid (deer) in some areas of North America. The disease is characterised by weight loss and behavioural changes in infected animals, usually over a period of weeks or months leading to death. CWD has not been found in the UK or elsewhere in Europe. No definitive or suspected cases of transmission of CWD to humans have been reported.

3. SEAC considered a review of the published, and some unpublished, research on CWD, together with surveillance data on TSEs in European cervids and information on UK cervid populations (1).

Origins

4. The origins of CWD are unknown. On the basis of epidemiological data, it is highly improbable that CWD originated from the recycling of mammalian protein in processed feed. It has been suggested that CWD may have arisen from transmission and adaptation of scrapie from sheep to cervids, as a result of a spontaneous change of endogenous prion protein (PrP) to an abnormal disease-associated form, or from an unknown source.

5. Data supporting any of these possible origins of CWD are either absent or equivocal. Although CWD could have originated from scrapie, the differing properties of the two prion diseases in strain typing bioassays, whilst limited, do not support this hypothesis. Evidence for multiple strains of CWD is equivocal. It seems most likely that CWD arose from a spontaneous change of endogenous PrP resulting in a disease-associated and laterally-transmissible form of PrP, although direct data to support this hypothesis are lacking.

Host range

6. The known natural hosts for CWD are mule deer (Odocoileus hemionus hemionus), black-tailed deer (Odocoileus hemionus columbianus), white-tailed deer (Odocoileus virginianus) and Rocky Mountain elk (Cervus elaphus nelsoni). The prevalence and geographical distribution of CWD in these species appears to be increasing in North America in a manner which is unlikely to be due simply to increased surveillance.

7. There are no direct data relating to the transmissibility of CWD to UK cervid species. However, comparison of a limited number of PrP codons indicates some homology in the endogenous PrP gene of European and North American cervid species. Thus, the possibility that UK cervids may be susceptible to CWD cannot be excluded, in particular red deer (Cervus elaphus elaphus) which are closely related to elk.

8. There is no evidence to suggest that CWD is present in UK cervids. However, because surveillance in the UK is very limited, a low level prevalence of CWD cannot be ruled out. The committee endorsed the opinion of the European Food Safety Authority on CWD surveillance in the European Union (2004) .

9. Transmission studies using parenteral routes of administration to cattle, sheep and a single goat, together with data from in vitro PrP conversion experiments, suggest that a significant barrier to CWD transmission to these species may exist. No transmission has been evident so far in an on-going oral transmission study in cattle after six years. Furthermore, no signs of infection have been observed from monitoring of cattle co-habiting areas with infected cervids, or in cattle, sheep or goats in close contact with infected cervids in research facilities. Thus, although the data are limited, there is currently no evidence to suggest that CWD can be transmitted naturally to cows, sheep or goats, and it is likely that there is a strong species barrier to such transmission.

Routes of transmission

10. Epidemiological data indicate that lateral transmission between infected and susceptible cervids occurring naturally is sufficiently effective to maintain epidemics in both captive and free-living populations. There is good evidence from studies of cervids inhabiting paddocks previously inhabited by infected animals or contaminated with infected carcases, that CWD can be transmitted laterally between animals via the environment. The precise mechanism of transmission is unclear. It is possible that the infectious agent is shed in the saliva, faeces or urine or as a result of decomposition of infected carcases and transferred to other cervids grazing the contaminated areas. It is also possible that some maternal transmission occurs.

11. There have also been suggestions that the lateral transmission of CWD may be influenced by environmental factors.

Pathogenesis

12. Information on the pathogenesis of CWD is limited. The data show that, following oral challenge, PrPCWD is first detected in the oral and gut-associated lymphoid tissues before spreading more widely within the lymphoid system and then to the brain. Involvement of the retropharyngeal lymph nodes or tonsils in the pathogenesis may not occur in some elk. At the microscopic level, the nature and distribution of the tissue lesions are similar to those found for scrapie. The available data suggest the pathogenesis of CWD is similar to scrapie.

BSE in UK deer

13. Both captive and free-ranging cervids in the UK may have been exposed to contaminated feed prior to the reinforced mammalian meat and bone meal ban instituted in 1996. A study to look at the potential susceptibility of red deer to BSE has shown no signs of transmission of the disease by the oral route, but it is at a very preliminary stage. Although a theoretical possibility exists, there is no evidence from the very limited surveillance data to suggest that BSE is present in the UK cervid population.

Human health implications

14. Epidemiological data on possible CWD infection of humans are very limited. The possibility that clinical symptoms of CWD in humans differ from those of Creutzfeldt-Jakob Disease (CJD) cannot be excluded. There is no significant difference between the prevalence of CJD in CWD endemic areas and other areas of the world. However, because CJD surveillance in the USA is relatively recent, not all CJD cases may have been identified. Additionally, detection of a small increase in prevalence of such a rare disease is very difficult. Investigation of six cases of prion disease in young people (< 30 years of age) in the USA found no definite causal link with consumption of venison from known CWD endemic areas. The disease characteristics in these cases were indistinguishable from sporadic CJD or Gerstmann-Sträussler-Scheinker syndrome. Likewise, in a study of three hunters (> 54 years of age) diagnosed with sporadic CJD, no link with consumption of venison from CWD endemic areas was found. No causal link was found in an investigation of three men with neurological illnesses who were known to partake in “wild game feasts”. Only one of these subjects was found to have a prion disease and this was also indistinguishable from sporadic CJD.

15. Preliminary results from transmission experiments in transgenic mice expressing human PrP suggest the presence of a significant species barrier to transmission of CWD to humans. However, these findings must be interpreted with caution as they may not accurately predict the human situation. Data from in vitro experiments on conversion of human PrP by disease-associated forms of PrP, including PrPCWD, are equivocal.

16. The committee concluded there is no evidence of transmission of CWD to humans from consumption of venison, and that there may be significant barriers to transmission. Nevertheless, as the data are extremely limited a risk cannot be ruled out should CWD enter UK herds.

Conclusions

17. There is no evidence that CWD (or BSE) is present in the UK cervid population. However, because only limited surveillance is conducted in the cervid population, a low level prevalence of CWD cannot be ruled out. It is recommended that further surveillance of TSEs in UK cervids is conducted.

18. There is no evidence of transmission of CWD to humans from consumption of meat from infected cervids. Although epidemiological and experimental data on potential transmission of CWD are extremely limited, they suggest that there may be a significant species barrier. It would be helpful if further studies were available assessing the potential species barrier for transmission to humans.

19. Although limited, there is no evidence CWD can be transmitted to cattle, sheep or goats by natural means.

20. In summary, it appears that CWD currently poses relatively little risk to human health, or to the health of cattle, sheep or goats in the UK. Nevertheless, as a risk cannot be excluded a watching brief should be maintained.


SEAC
January 2005

http://www.seac.gov.uk/statements/state180105.htm

10:00
Chronic Wasting Disease in UK deer
Alan Harvey (FSA).Wildlife Information Network.
85/2*(pdf)


http://www.seac.gov.uk/papers/tsesdeer-%20final.pdf

Annex 1 (pdf)

http://www.seac.gov.uk/papers/cwdiseaseannex1.pdf

Annex 2 (pdf):

http://europa.eu.int/comm/food/fs/sc/ssc/out324_en.pdf

Annex 3 (incl. appendices) (pdf)

http://www.seac.gov.uk/papers/munrodeerrptannex3.pdf

Annex 4 (pdf)

http://www.seac.gov.uk/papers/deersurvannex4.pdf

Annex 5 (pdf):


http://www.seac.gov.uk/papers/efsa-annex%205.pdf


ALL of these false reassurances we have heard time and time again, and ALL have been proven wrong.

AS with the BSE TO HUMANS AND BSE to GOAT. IT was always it never happend under natural conditions, just in the lab, so not to worry. NOW WE HAVE TO WORRY;

http://www.jarvm.com/articles/Vol2Iss1/DEBOSSCHERE.htm

http://www.pnas.org/cgi/content/full/041490898v1



WHILE animals under 12 months of age have been diagnosed
with pre-clinical infection by IHC, the YOUNGEST ELK
DIAGNOSED WITH CLINICAL CWD WAS 17 MONTHS
OLD. Canadian veterinary services consider that the incubation
period for CWD is 16-36 months, with a mean of 22 months.
With elk, as with deer, animals of all ages and both sexes have
been found infected with CWD and no bias had been evident...

snip...

CONCLUSION

CWD is spreading and may have the potential to infect humans...

FULL TEXT ;

Chronic Wasting Disease in deer and elk: Scientific Facts and Findings

Mo. D. SALMAN

Animal Population Health Institute, College of Veterinary Medicine
and Biomedical Sciences, Colorado State University, Fort Collins,
Colorado 80523-1681, USA

(Received 12 April 2003/Accepted 2 June 2003)

http://www.jstage.jst.go.jp/article/jvms/65/7/761/_pdf



In Confidence - Perceptions of unconventional slow virus diseases
of animals in the USA - APRIL-MAY 1989 - G A H Wells


CWD TO PRIMATES PAGE 24 - 27

PAGE 25

Transmission Studies

Mule deer transmissions of CWD were by intracerebral inoculation and
compared with natural cases resulted in a more rapidly
progressive clinical disease with repeated episodes of synocopy ending
in coma. One control animal became affected, it is believed through
contamination of inoculam (?saline). Further CWD transmissions were
carried out by Dick Marsh into ferret, mink and squirrel monkey.
Transmission occurred in all of these species with the shortest
incubation period in the ferret.

snip...

The occurrence of CWD must be viewed against the context of the
locations in which it occurred. It was an incidental and unwelcome
complication of the respective wildlife research programmes. Despite its
subsequent recognition as a new disease of cervids, therefore justifying
direct investigation, no specific research funding was forthcoming.
The USDA viewed it as a wildlife problem and consequently not their
province!

[figures...TSS]

snip...

VISIT TO USA - DR A E WRATHALL - INFO ON BSE AND SCRAPIE

1. Dr Clark lately of the Scrapie Research Unit, Mission Texas has
successfully transmitted ovine and caprine scrapie to cattle. The
experimental results have not been published but there are plans to do
this. This work was initiated in 1978. A summary of it is:-

better cut this short, you can read full text of part 2 here;

snip...

In Reply to: In Confidence - Perceptions of unconventional slow virus
diseases of animals in the USA - APRIL-MAY 1989 - G A H Wells

http://www.bseinquiry.gov.uk/files/mb/m11b/tab01.pdf

As implied in the Inset 25, we must not _ASSUME_ that transmission
of BSE to other species will invariably present pathology typical
of a scrapie-like disease...

snip...

G A H WELLS 4 January 1991

http://www.bseinquiry.gov.uk/files/yb/1991/01/04004001.pdf


Is there a Scrapie-like disease in cattle in USA

http://www.bseinquiry.gov.uk/files/mb/m09a/tab01.pdf

http://www.bseinquiry.gov.uk/files/mb/m09/tab05.pdf


BASE in cattle in Italy of Identification of a second bovine amyloidotic
spongiform encephalopathy:
Molecular similarities with sporadic Creutzfeldt-Jakob disease

http://www.pnas.org/cgi/content/abstract/0305777101v1

Adaptation of the bovine spongiform encephalopathy agent to primates and
comparison with
Creutzfeldt- Jakob disease: Implications for human health THE findings
from Corinne Ida Lasmézas*,
[dagger] , Jean-Guy Fournier*, Virginie Nouvel*, Hermann Boe*, Domíníque
Marcé*, François Lamoury*,
Nicolas Kopp [Dagger ] , Jean-Jacques Hauw§, James Ironside¶, Moira
Bruce [||] , Dominique Dormont*,
and Jean-Philippe Deslys* et al, that The agent responsible for French
iatrogenic growth hormone-linked CJD
taken as a control is very different from vCJD but is similar to that
found in one case of sporadic CJD and
one sheep scrapie isolate;

http://www.pnas.org/cgi/content/full/041490898v1


Characterization of two distinct prion strains derived from bovine
spongiform encephalopathy transmissions to
inbred mice

http://vir.sgmjournals.org/cgi/content/abstract/85/8/2471

TSS



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