CWD -2006 Summary
CHRONIC WASTING DISEASE, CERVIDS - USA: 2006 SUMMARY
Following is an excerpt of the 2006 annual report of the [U.S.
Congressional] Committee on Captive Wildlife and Alternative
Livestock, dated 15 Jan 2007.
Drs. Dean Goeldner and Tom Gidlewski, VS (Veterinary Services), APHIS
(USDA Animal and Plant Health Inspection Service), USDA (United
States Department of Agriculture), presented the APHIS-VS chronic
wasting disease (CWD) program update. CWD has been discovered in
free-ranging cervids in 11 states and 41 captive cervid herds in 9
states. There are currently 4 infected elk herds and one infected
white-tailed deer herd that have [been] chosen to remain under
quarantine instead of depopulate.
In 2006, the CWD program depopulated one elk herd in the endemic
area, which turned out to be infected as well as a chronically
infected white-tailed deer herd and a mixed elk and white-tailed deer
herd for a total of approximately 110 animals.
For the last 3 years, the program has paid for testing about 15 000
captive cervids per year. Demand for testing is expected to increase
with the implementation of the program. The 1st infected free-ranging
white-tailed deer was found in northwest Kansas in 2006. On the
positive side, New York found no additional positive free-ranging
cervids in 2006 but West Virginia found 4 additional animals in
Hampshire County.
Wisconsin continues to aggressively battle CWD with over 100 000
animals submitted for testing since 2000 and over 650 positive deer
identified. The infected area appears to be largely limited to the
original counties. Interestingly, the number of deer in the Wisconsin
endemic area does not appear to be decreasing despite the large
number of animals that have been removed. Colorado has stopped
culling deer in "hot spots" as they believe that it was not very
successful.
Alberta, Canada continues to find more positive white-tailed deer
adjacent to the infected Saskatchewan areas.
Appropriate tissue collection and submission for CWD diagnosis
includes obex, medial retropharyngeal lymph nodes, and palatine
tonsils. Submission of an ear with the official ear tag attached or
submission of fresh tissue accompanied by an appropriately executed
chain of evidence document will allow DNA comparison in the event of
a positive diagnosis. Archiving herd blood samples on special
collection cards is also a way to compare DNA in the event of a
positive diagnosis in the future. All positive cases are verified by
2 pathologists and the presumptive positive tissues are completely
retested at the National Veterinary Services Laboratory (NVSL).
Rectal biopsy continues to be examined as a tool for CWD ante-mortem
diagnosis. Hundreds of animals have been examined and the results
look promising. Larger numbers need to be examined in order to make
final conclusions.
Retrospective epidemiologic analysis and transgenic mouse research in
2006 still support the theory that CWD does not appear to affect
people or non-cervid animals.
APHIS received approximately USD 18.5 million in appropriated CWD
funding in FY (fiscal year) 2006, including USD 2.44 million in
congressional earmarks. Congress has not passed the FY 2007
appropriations; the president's budget requests USD 15.4 million for CWD.
On 21 Jul 2006, APHIS published its final CWD rule. The final rule
added moose and all cervid species to the previously announced deer
and elk species covered in the herd certification program. It
- expanded the term "captive" to "farmed and captive"
- maintained a 5-year surveillance standard for surveillance
- clarified that 2 positive official tests are needed for a CWD diagnosis
- reduced the minimum testing age to 12 months
- adjusted commingling buffers
- eliminated the 48-hour exemption for short-term commingling
- changed the identification (ID) requirement to one official ID and
one ID unique within the herd; and
- added the reporting of escapes and disappearances.