Sludge Watch ==> USA Wyoming - first report of sheep infected with atypical Scrapie

[Maureen Reilly]

Sludgewatch Admin:
For the new readers - Scrapie is a sheep version of BSE or Mad Cow Disease.


Scrapie, atypical, sheep - USA (Wyoming): first report
17.mar.07
A ProMED-mail post
http://www.promedmail.org
Date: 17 Mar 2007
From: Terry Singeltary flounder9 at verizon.net
Source: Gazette News Services [edited]

http: 
//www.billingsgazette.net/articles/2007/03/17/news/wyoming/64-scrapie.txt
Rare form of scrapie found in sheep; United States documents 1st case
rare Nor98 scrapie strain

The Wyoming Livestock Board says a sheep from a flock in the northeastern 
corner of the state has tested positive for a rare form of the disease 
scrapie, the 1st time the particular strain has been found in the United 
States.
The USDA Animal Plant Health Inspection Service [APHIS] notified the state 
Friday [16 Mar 2007] that the ewe tested positive for a form of scrapie 
consistent with the Nor98 strain, 1st diagnosed in Norway in 1998.
The livestock board said it doesn't expect the strain of the disease to 
become a major problem for the Wyoming sheep industry. State and federal 
officials intend to monitor the remainder of the flock, near the Black 
Hills, to make sure the disease doesn't become established.
According to a release from the livestock board, the ewe was slaughtered in 
Michigan as part of the USDA's regular scrapie slaughter surveillance 
program and traced back to the Wyoming flock.
The release states that the Nor98 strain of scrapie is rare even in Europe, 
with fewer than 300 cases diagnosed since it was identified in 1998.
Scrapie is a transmissible disease similar to chronic wasting disease found 
in deer and elk. Scrapie is limited to sheep and goats and takes years to 
affect an animal after it has been infected.
There are no known human health risks associated with scrapie.
"This provides evidence that the surveillance program is working," said 
Bryce Reece, executive director of the Wyoming Wool Growers Association. "It 
also indicates that the program is on the cutting edge of science to detect 
such a rare disease during standard surveillance." An epidemiological 
investigation is ongoing.
--
Terry S. Singeltary Sr.
flounder9 at verizon.net

[Scrapie is a fatal, degenerative disease affecting the central nervous 
system of sheep and goats. It is among a number of diseases classified as 
transmissible spongiform encephalopathies (TSE). Infected flocks that 
contain a high percentage of susceptible animals can experience significant 
production losses. Over a period of several years, the number of infected 
animals increases, and the age at onset of clinical signs decreases, making 
these flocks economically unviable.

First recognized as a disease of sheep in Great Britain and other countries 
of Western Europe more than 250 years ago, scrapie has been reported 
throughout the world. Only 2 countries are recognized by the United States 
as being free of scrapie: Australia and New Zealand.
The 1st case of scrapie in the United States was diagnosed in 1947 in a 
Michigan flock. The flock owner had imported sheep of British origin through 
Canada for several years. APHIS conducted a slaughter surveillance study 
from 1 Apr 2002 to 31 Mar 2003, which determined the prevalence of scrapie 
in mature U.S. cull sheep to be 0.2 percent or one positive out of 500 cull 
sheep.
This particular strain was identified in Norway in 1998, in ARR/ARR genotype 
sheep. Some would argue this raises important issues with regard to control 
of scrapie infection in small ruminants. Of major concern, ARR/ARR sheep can 
no longer be regarded as free of natural TSE infection.

The research on this particular strain can be viewed in its entirety at 
http://www.pnas.org/cgi/content/full/102/44/16031.

Much of this paper was done on transgenic mice. This moderator contends that 
mice and sheep are a long way apart physiologically and everything found in 
a mouse is not necessarily the final word for research.

Portions of this posting have been extracted from:
http://www.aphis.usda.gov/lpa/pubs/fsheet_faq_notice/fs_ahscrapie.html.
Mod.TG]