Well, I was just talking to a colleague about CWD and up comes a news release
from Minnesota. The disease has been found in a single game farmed elk in Aitkin
County (see attached news release). This is the second state in the midwest, the
first case in Minnesota.
On that subject, Damien Joly and I were discussing genetic susceptibility of
elk and potential for non-lethal or at least very long incubation period for CWD
in elk. This was relative to the new CWD case in South Dakota. In my update I
mentioned Dr. Sam Holland suspected another, undetected case and my comment on
measures taken to find other CWD cases ("though all mortalities were
required to be examined and they monitored the inventory of the herd") was
not meant to imply any CWD-affected animal would have been detected. An
asymptomatic carrier/disperser, incubating animal, is certainly possible.
However, the main issue I was discussing was how was the disease introduced
into the new pen? Three main vehicles seem likely knowing what we know about the
herd, monitoring, and inventory: 1. fence to fence contact for 2 months in 1998.
2. scavenger/other biota moving CWD from one side to the other, 3. environmental
contamination, drainage and environmental contamination of the new site. A
fourth option, that is a new, spontaneously arisen case of CWD seems farfetched,
but is also possible. Thanks, Damien for the discussion.
State of Minnesota
FOR IMMEDIATE RELEASE: Friday, August 30,
2002
Contacts:
Michael Schommer, Communications Director, 651-260-2956
Bill Hartmann, State Veterinarian, 651-296-2942, x27
Chronic
Wasting Disease found in a farmed elk from Aitkin County
Case marks the
first time this disease has been detected in Minnesota
ST. PAUL, Minn. – The Minnesota Board of Animal
Health today announced that a single animal from an Aitkin County farmed elk
herd has tested positive for Chronic Wasting Disease (CWD).
The case marks the first time this disease of elk and deer has been
detected in Minnesota.
A sample of the five-year-old male elk’s brain was
submitted to the U.S. Department of Agriculture’s National Veterinary
Services Laboratories (NVSL) in Ames, Iowa, after the animal died from an
unknown illness. Subsequent
testing at NVSL confirmed that the animal had CWD.
NVSL’s positive finding prompted the Board of Animal Health to
immediately quarantine the herd. This
quarantine means no animals can move on or off the farm.
In the coming days, the disposition of the herd will be determined.
Meanwhile, officials continue to investigate the source of the
infection and whether other animals may have been exposed.
Four years ago, Minnesota implemented a voluntary CWD
monitoring program for farmed deer and elk herds. Every time an adult deer or elk from one of the enrolled
farms dies or is slaughtered, its brain is tested for CWD. The herd from which the CWD positive animal came was enrolled
in the monitoring program since 2000, and in that time four other animals were
tested for CWD. All four animals
tested negative.
CWD is a fatal brain and nervous system disease found in
elk and deer in certain parts of North America.
The disease is caused by an abnormally shaped protein called a prion,
which can damage brain and nerve tissue.
Infected animals show progressive loss of body weight with accompanying
behavioral changes. In later
stages of the disease, infected animals become emaciated (thus “wasting”
disease). Other signs include
staggering, consuming large amounts of water, excessive urination, and
drooling.
According to state health officials and the federal
Centers for Disease Control and Prevention, there is no evidence that CWD can
be transmitted to humans.
Until this case was reported, CWD had never been found in
Minnesota. There have been cases
in farmed elk in Colorado, South Dakota, Oklahoma, Kansas, Nebraska, Montana
and Alberta and Saskatchewan, Canada. Cases
have also been found in wild deer in Wisconsin, Wyoming, Colorado, South
Dakota, Nebraska, New Mexico and Saskatchewan.
Thomas J. Roffe, PhD, DVM
Northern Rocky Mountain Science Center
USGS-BRD
FWP Bldg, 1400 S. 19th Ave.
Bozeman, MT
T: 406-994-5789
F: 406-994-4090
Cell: 406-539-4955
