Office of the Regional Executive for Biology - Central Region
5-14-2002
A few points of interest.
First on CWD: one of the big concerns is
transmissibility to humans. An NIH study suggested such transmissions would be
difficult based on experimental transmissions. However, in data I've seen
reported it appeared transmission from BSE affected material would be just about
as difficult. The low number of cases of CWD combined with the few people thus
far actually exposed to CWD would make CWD in humans almost undetectable if
transmission was at the same rate as BSE to humans. That is not to say CWD can
be transmitted and simply hasn't been found. Just that the data to prove the
negative (that transmission cannot occur) is very difficult to come by.
The whole idea of TSEs being spread by urine used by hunting
interests is interesting and theoretical. However prion protein has been
detected in urine, though to my knowledge the abnormal proteinase resistant form
hasn't. In BSE and scrapie infected animals specific physiologic and metabolic
markers have been found in urine. This may provide a basis for an antemortem
test.Note the continued debate on
who is to blame for origination and spread of CWD.
A fourth case of BSE has been found in Japan. All four cases
have been found in dairy cattle and as I've mentioned before there are several
guesses as to the potential source, including milk replacer. Japan continues to
be the only Asian country identified with this TSE. The first case of BSE was
reported in Poland the weekend of May 4, in a 9 year old cow. Poland imported a
significant amount of meat and bone meal (MBM) through 1997. MBM has been
identified as one of the primary risk factors for BSE transmission.
The total number of people affected by vCJD is about 130. In
recent UK data (as of 6 May 02), the number of deaths from confirmed or probable
vCJD is 111 with 10 living with probable vCJD. The UK total is then 121, and
about 10-12 cases outside the UK have been reported.
Thomas J. Roffe, PhD, DVM
USGS-BRD
Northern Rocky Mountain Science Center
FWP Bldg, 1400 S. 19th Ave.
Bozeman, MT 59718-5496
T: 406-994-5789
F: 406-994-4090
Cell: 406-539-4955
Supporting
Documents:
Date: 8 May 2002
From: ProMED-mail <promed@promedmail.org>
Source: Reuters, 6 May 2002 [edited]
<http://www.reuters.com/news_article.jhtml?type=healthnews&StoryID=923139&fromEmail=true>
There is no evidence that CWD, first identified in 1967, has
ever spread to humans, cattle, or any species other than deer and elk. In one
2000 study, National Institutes of Health researchers at Rocky Mountain
Laboratories in Hamilton, Montana determined that a molecular barrier appeared
to help prevent CWD from jumping to other species.
However, the researchers were able to get a low quantity of
diseased deer proteins, called prions, to convert healthy human prions to the
diseased form, suggesting it might be possible for humans to get CWD. Byron
Caughey, one of the Rocky Mountain researchers behind the study, cautioned
that it was difficult to draw any firm conclusions from the study about the
human risk of CWD.
"This is a test-tube reaction that is a poor surrogate
for actual transmission studies in the real world, but no one wants to
actually test whether CWD can infect humans," he said. "Our work
suggests that while it may be possible for humans to get CWD, it's likely to
be a low-efficiency process," he said.
Wisconsin Dept. of Natural Resources spokesman Bob Manwell
conceded that the recommendations on venison were "a little bit vague.
(But) it's similar to a lot of health advice that is given out, where it
really comes down to a personal decision. There is a small risk, and it's the
individual's decision as to how they feel about that," Manwell said.
Manwell said that for now, the state planned to go ahead
this fall with a deer donation program that provided meat to food pantries and
needy families. Hunters donated 3921 deer to the program last year, resulting
in about 176 000 pounds of venison. "Even after the realization that we
have this disease in the state, there has still been demand for the
meat," Manwell said. "It's really going to be up to individual food
pantry organizations what they want to do about it."
Date: 6 May 2002
From: ProMED-mail <promed@promedmail.org
Source: National Post [edited]
<http://www.nationalpost.com/news/national/story.html?f=/stories/20020506/133605.html>
Canada: Deer hunters could be spreading
lethal germs
Illness related to mad cow disease, experts say
CALGARY - Hunters may be unwittingly spreading Chronic
Wasting Disease (CWD) by using deer scents made from the urine of infected
animals in game farms, some scientists and hunting advocates fear.
The packaged scents, spread on the ground by hunters to lure
quarry, could contain prions, the resilient agent scientists blame for CWD, an
illness related to mad cow disease that is associated with animals in fenced
game farms.
Although the link between deer scents and CWD has not been
studied, several experts say there is a "theoretical risk" that CWD
could be spread by the deer attractants.
Rob Miskosky, editor of Alberta Outdoorsmen, says some game
farmers are packaging deer scents to diversify in an industry tainted by
outbreaks of CWD and reeling from bans on shooting captive animals and
collapsed Asian markets for elk antler velvet. One consortium of Alberta game
farmers is constructing a facility capable of collecting 1000 ounces of urine
a day from deer.
Norm Moore, a game farmer and industry spokesman,
dismisses the concerns, saying the industry is strictly monitored for disease.
"We have an identification and tracking system that is second to none in
agriculture," he said.
Although packaged scents are not tested for safety,
Mr. Moore says health precautions undertaken by game ranchers make it unlikely
any disease would be associated with the packaged urine. "I don't think
there are any regulations specifically for that product, but [game farm] herds
would have to be on the normal health program or they couldn't have the
animals," Mr. Moore said.
Darrel Rowledge, director of the advocacy group
Alliance for Public Wildlife, says it is astonishing such products, which have
been used by hunters for decades, are released into the marketplace untested.
Hunters spread the scents, made from a combination of urine and feces, on
their boots and clothing and on trees, branches, rock, grasses and the ground.
Mr. Miskosky, writing in the current edition of Alberta
Outdoorsmen, says scientific journals confirm TSE prions, the mutant protein
causing CWD, have been found in urine long before the disease is detected in
animals and could remain viable
in soil for years. Destroying the prions requires incineration of an infected
animal in temperatures higher than 600 Celsius.
The Canadian Food Inspection Agency (CFIA) is investigating
1 case of CWD in Alberta. Dr. George Luterbach, a CFIA veterinarian, said all
72 animals on the infected farm will be destroyed and a compensation package
is being worked out with the rancher. In Saskatchewan, about 8000 elk from
game farms were destroyed last year after an outbreak of the disease, which
was confirmed in more than 200 animals.
The cost to federal taxpayers of controlling the
Saskatchewan outbreak has been estimated by one animal rights group at $60
million [Canadian], including compensation to the affected game farmers.
Dr. Luterbach said the agency is also waiting for lab test
results on 12 animals from the infected Alberta farm that were sold to other
game ranchers. If the tests come back positive, it is likely all the animals
on the other farms will also be destroyed, he said.
The game farming industry says it is unfairly blamed for CWD.
Mr. Moore says the disease started in the wild in Colorado, spread into a zoo
and was then passed into captive herds when a stricken zoo animal was sold to
a game farm, where it spread among the contained herd. The industry's
stringent testing makes it a lightning rod for CWD because its detection
system is unmatched by public wildlife administrators, he said.
Game farmers sell the meat of wild game such as deer and elk
-- which is low in fat and cholesterol -- to restaurants.
Date: 10 May 2002
From: ProMED-mail <promed@promedmail.org
Source: Meat and Livestock Commission, UK
"Testing for transmissible spongiform encephalopathies in cattle and
sheep"
<http://www.mlc.org.uk/>
Urine tests
Alternative diagnostic tests in the live animal involve the
detection of disease specific physiological or metabolic markers. These are
secondary substances produced as a result of infection. Such markers,
apparently related, have been identified in serum and in urine. Whether or not
they remain specific to BSE or scrapie remains to be proven.
Changes have been detected in the constituents of
urine of CJD patients, sheep with scrapie and cattle with BSE. Molecules that
may be disease specific have been found in cattle and further work is in
progress to develop and validate a diagnostic test. The time of appearance of
this substance at detectable levels in the disease is unknown. Work is
underway to determine when these changes are first detectable in the long
incubatioperiod of BSE.
Date: 11 May 2002
From: ProMED-mail <promed@promedmail.org>
Source: ABC news [edited] <http://www.abcnews.go.com/wire/US/reuters20020511_127.html>
Japan Reports Fourth Case of Mad Cow
Disease
TOKYO: Tests on Saturday confirmed another case of mad cow
disease in Japan, the first since November and the fourth since an
outbreak last September that
devastated the country's food sector and battered consumer confidence. The
Health Ministry said tests at a university in Hokkaido, northern Japan, had
confirmed a preliminary positive test for the brain-wasting illness.
It said the case was still pending final determination by a
panel of experts, which would make an announcement on Monday.
Formally known as bovine spongiform encephalopathy (BSE),
mad cow disease has been linked to variant Creutzfeldt-Jakob disease, which
has killed about 100 people in Europe but none in Japan.
The outbreak has gutted Japan's appetite for beef, battered
the earnings of food companies and restaurants, and damaged the faith of
consumers in the country's food-safety standards.
Satoshi Takaya, director of the health ministry's food
safety division, told reporters the six-year old Holstein cow that had tested
positive had come from a dairy farm on Hokkaido island.
Since October, Japan has tested all the cows slaughtered for
beef for the disease.
The Farm Ministry said last month that it estimated the
total industry-wide damage of BSE at up to 2.95 billion Dollars but the report
of the new case comes at a time when there were signs that confidence in beef
was returning.
The latest case comes just four weeks before thousands of
visitors are due to arrive in Japan for the World Cup soccer tournament, which
it is co-hosting with South Korea. South Korea has its own problems,
confirming last week another outbreak of foot and mouth disease in its pig
population.
That disease is considered harmless for humans, but
threatens nevertheless to damage consumer confidence.
Cattle are believed to contract mad cow disease by eating
meat-and-bone meal contaminated with BSE, but officials have not pinned down
the source of the outbreak in Japan.
An investigating panel last month slammed the government for
ignoring warnings from both the World Health Organization and the European
Commission that could have prevented the crisis.
Japan's total beef imports are expected to hit 506 000
tonnes this year, down 25 percent from 2001. Most imports come from the United
States, although Australia is also a major supplier.
The weighted average price of domestic beef on the Tokyo
Meat Market hit 6.54 Dollars per kg this week -- a significant recovery from
lows plumbed in September, but well off levels before the first outbreak on 10
Sep 2002.
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