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Cwd in Norway

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CHRONIC WASTING DISEASE, CERVID - NORWAY: REINDEER HERD SLAUGHTER
*****************************************************************
A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases
<http://www.isid.org>

Date: Mon 3 Apr 2017 5:30 PM
Source: Science Magazine [edited]
<http://www.sciencemag.org/news/2017/04/norway-plans-exterminate-large-reindeer-herd-stop-fatal-infectious-brain-disease>


A year after a deadly and highly contagious wildlife disease surfaced
in Norway, the country is taking action. Chronic wasting disease
(CWD), caused by misfolded proteins called prions, has already ravaged
deer and elk in North America, costing rural economies millions in
lost revenue from hunting. Its presence in Norway's reindeer and moose
-- the 1st cases in Europe -- is "a very serious situation for the
environment and for our culture and traditions," says Bj?rnar
Ytrehus, a veterinary researcher at the Norwegian Institute for Nature
Research in Trondheim.

Last week [week of 26 Mar 2017], Norway's minister of agriculture and
food gave the green light for hunters to kill off the entire herd in
which 3 infected individuals were found, about 2000 reindeer, or
nearly 6 per cent of the country's wild population. "We have to take
action now," says Karen Johanne Baalsrud, director of plant and animal
health at the Norwegian Food Safety Authority in Oslo. The deer's
habitat will be quarantined for at least 5 years to prevent
reinfection. The odds of a successful eradication, experts say, will
depend largely on how long CWD has been present in Norway. [This is a
factor that is unknown. - Mod.TG]

CWD, discovered in 1967, has been found in 24 US states and 2 Canadian
provinces, and it has been spread in part by shipments of infected
animals. Many species of cervids are susceptible, including elk,
moose, and several kinds of deer. Infected animals typically begin
showing signs such as weight loss, lethargy, and drooling 2 to 3 years
after infection and then die within months. In Wyoming, where CWD has
been endemic for decades, up to 40 per cent of some herds are
infected, and white-tailed deer populations are declining by 10 per
cent a year.

CWD is very contagious: Prions spread easily through saliva, urine,
and feces, and can linger in the environment for years, which suggests
that feeding stations and salt licks are hot spots of infection. Once
the disease has become firmly established, environmental contamination
makes eradication very hard, says Christina Sigurdson, a prion
researcher at the University of California, San Diego. "It hasn't been
shown so far to be possible," she says. There's no evidence that
humans can get sick from eating infected deer, but it is not
recommended. (Mad cow disease, also caused by prions, can infect
people who eat contaminated meat and has caused more than 200 deaths
so far.) [Please note, the expert cited here says that eradication in
the environment has not been shown to be possible so far. It would be
useful to know on what scientific data the decision was made that 5
years is a long enough a quarantine. - Mod.TG]

Norway's 1st CWD case was detected by chance after wildlife biologists
working in the rugged mountains of Nordfjella found a sick young
reindeer on 15 March 2016. After its death, tests at the Norwegian
Veterinary Institute (NVI) in Oslo pointed to CWD. "I couldn't believe
it," says NVI prion researcher Sylvie Benestad. But international
reference labs confirmed her diagnosis.

The prions resemble those found in North American deer, Benestad and
her colleagues have found. How the disease got to Norway is a mystery.
Prions may have arrived in deer urine, which is bottled in the United
States and sold as a lure, or perhaps they hitched a ride on hiking
boots or hunting gear. But prion diseases can also start
spontaneously, after proteins begin to misfold in a single individual,
and Benestad's hunch is that this is a more likely scenario.
[Paragraph 4, above, states, "Prions spread easily through saliva,
urine, and feces, and can linger in the environment for years..." so
if urine is imported as a lure, then they may have imported it. -
Mod.TG]

After the initial discovery, Norwegian officials began looking for
other cases. A local hunter found 2 moose with CWD near the town of
Selbu, 40 kilometers [25 miles] south east of Trondheim (see map on
original page), in May 2016. During last fall's hunting season,
thousands of hunters and other volunteers collected about 8000 brain
samples from all over the country, turning up 2 more cases of infected
reindeer near Nordfjella. The cases in Nordfjella and Selbu are likely
not linked, says Benestad, as the reindeer and moose have different
types of prions.

Hot zone
Reindeer will be slaughtered in Nordfjella, Norway; no culling is
recommended for the area near Trondheim where 2 moose with CWD have
been found.

An advisory panel convened by the Norwegian Scientific Committee for
Food Safety last week [week of 26 Mar 2017] suggested different
approaches for the 2 locations. Around Selbu, it recommended increased
surveillance, but no culling of moose yet. The 2 infected moose were
older animals, suggesting that these were cases of spontaneous
disease, which are less likely to be infectious. (The reason why: In
spontaneous cases of prion disease, such as in sheep, prions are only
found in the brain.) And even if the unusual prions in moose are
contagious, the solitary nature of these animals lowers the chances of
transmission.

Reindeer, however, are the most gregarious of cervids, and the 3 sick
individuals in Nordfjella could easily have spread prions. Culling the
entire herd would be "drastic", the panel acknowledged, but should be
attempted as soon as possible. The slaughter, to start in August, will
be carried out by amateur hunters, who can eat the meat if prion tests
come back negative. Professional sharpshooters will be used to find
any elusive survivors. "We will do whatever it takes," says Erik Lund,
a senior wildlife adviser at the Norwegian Environment Agency in
Trondheim. [This article acknowledges that this is a drastic
procedure. Given that urine can contain prions, then it is likely that
the infected animals have already peed their prion to the environment
and possibly to other animals. - Mod.TG]

Until the operation begins, wildlife rangers are patrolling to prevent
animals from leaving or entering the herd's 2000-square-kilometer
habitat. The area is ringed by paved roads, which reindeer don't like
to cross, but if any do, the rangers have orders to track down and
kill them. Repopulation won't begin until at least 2022. Benestad says
testing old feces may be a way to check whether prions lingering in
the environment have degraded. [Do prions degrade at the same rate as
the feces? Is there a reliable test for prions in degrading feces? -
Mod.TG]

Based on the prevalence in Nordfjella -- estimated at 1 per cent --
Lund guesses that CWD may have been present for only 5 to 7 years,
which could mean contamination is minimal. "There's a good chance they
can solve the problem," says wildlife ecologist Michael Samuel of the
University of Wisconsin in Madison. Quick response has been shown to
work before: In 2005, routine testing revealed CWD on 2 deer farms in
central New York. Strict regulations prevented the disease from
spreading. The state has seen no cases since.

But it's also possible that CWD is lurking elsewhere in Norway, the
panel noted. The agencies will collect another 20 000 samples in the
coming hunting season, and they plan to continue monitoring for years
to come. The specter of CWD has also alarmed the European Food Safety
Authority, which released a report in January [2017] recommending that
7 nearby countries all begin 3-year sampling programs.

Clarification, 4 April, 4.20 p.m.: The paragraph explaining why no
culling is planned around Selbu has been edited to make it clearer.

[byline: Erik Stokstad]

--
communicated by:
ProMED-mail
<promed@promedmail.org>

[This article does not provide any indication that the reindeer
owner(s) will be indemnified in any way. This is a brutal blow to the
owner's loss of his animals, his income, and apparently his property
as well. One wonders how he will make a living now that his land and
livelihood are being removed.

This article cites NY as being a success at eradicating this disease.
Yet, with disease of any kind it is always a case of search and you
shall find. Furthermore the case in NY was a deer in confinement, a
deer in captivity for raising. Consequently, since it was a confined
deer, then the chances of spread were much less. The date line and
plan of the follow-up procedures in NY can be found on
<http://www.dec.ny.gov/animals/33220.html>.

Other states have tried to kill their way out of CWD situations with
little or no success.

This area sounds large and although roads are thought to contain the
reindeer, the roads may not prevent other wildlife from dragging
carcasses in or from other infected cervids having contact with the
land or the reindeer.

Aside from a captive deer with CWD and NY's experience I see nothing
scientific about the justification for the slaughter of these
animals.

>From the discussion chapter in a 2016 Norwegian paper (open access at
<https://veterinaryresearch.biomedcentral.com/articles/10.1186/s13567-016-0375-4>).
[Please note the sentences or paragraphs marked with * as important.
Please also note the references are in the article cited above. -
Mod.TG]

A major question concerns the origin of CWD in Norway. Importation of
CWD infected deer could be the source of infection, as was the case in
South Korea. However, Norway has strict legislation and enforcement
regarding the importation of live animals and importation of cervids
is not allowed. The only exceptions are a few moose that have been
imported to zoos from Sweden. All red deer (_Cervus elaphus_) kept in
farms originate from wild Norwegian populations. It seems unlikely
that this CWD case is due to imported infected cervids unless illegal
imports from North America to Norway have taken place. It is however
noteworthy that Finland's white tailed deer population, estimated at
60 000 animals, originated from 1 import from North America in 1934 of
4 does and 1 buck. Due to the CWD situation in North America, Finland
targeted TSE testing especially to the white tailed deer in the period
between 2003 and 2015, and a total of 643 white tailed deer have been
tested and found negative for CWD (Sirkka-Liisa Korpenfelt, EVIRA,
Finland, personal communication).

Another possibility of contamination is through hunting urine baits
imported from North America, but for the time being, no information
about the use of these baits in Norway is available.

It has been speculated that the origin of CWD in North American
cervids may be associated with classical scrapie because some scrapie
infected sheep had been penned together with deer at a research center
between 1968 and 1971 [4, 15, 16]. To support this hypothesis,
Tamg?ney [17] reported the successful transmission of one classical
scrapie isolate into transgenic mice carrying the elk prion protein
gene [Tg(ElkPrP) mice], but it is noteworthy that the agent signature
(as defined by lesion profile) in these mice was different from that
in mice inoculated with CWD, suggesting that the scrapie and CWD agent
were distinct strains. Norway has had a scrapie surveillance program
in place since 1997 with a total of 264 000 small ruminants analyzed.
Few cases of classical scrapie have been diagnosed in Norway and the
last case was identified in 2009. There are no reports of classical
scrapie within the range of the Nordfjella reindeer sub-population,
but as sheep traditionally are transported over long distances to
graze in mountain pastures, it cannot be formally excluded that
reindeer in this or a nearby subpopulation could have been exposed to
sheep with classical scrapie at some point of time.

*In contrast to classical scrapie is Nor98/atypical scrapie diagnosed
in sheep in Norway. Between 5 and 13 cases have been identified each
year the past 10 years, and they are found over the whole country,
including where the CWD reindeer was discovered. Whether
Nor98/atypical scrapie could be the source of CWD in Norway cannot be
excluded, despite the fact that, as it could be expected in case of
direct transmission, the distinctive molecular signature of
Nor98/atypical scrapie, a multiband WB pattern [18] was not observed
in the present reindeer.

*A plausible alternative to the occurrence of CWD in Europe could be
that a cervid developed a genetic or spontaneous transmissible
spongiform encephalopathy which subsequently spread horizontally to
other cervids. As cervids may eat or gnaw on remnants of carcasses, we
may speculate that there could have been an incident more or less
analogous to the Kuru epidemic on Papua New Guinea, which is suggested
to have started with ritual cannibalism of an individual with sporadic
Creutzfeldt-Jakob Disease [19].

Currently we have no information about the distribution and prevalence
of CWD in the Norwegian cervid population. Whether CWD is contagious
among reindeer is also an open question, but should be expected. The
social behavior of reindeer living close together in herds and grazing
on the ground may increase the likelihood for CWD transmission. As
opposed to most of the prion diseases, infectivity in cervids is
demonstrated in many peripheral tissues, such as muscles [20], elk
antler velvet [21], endocrine glands [22] and in excreta like urine,
saliva, blood and feces [23, 24, 25, 26]. In the present reindeer,
PrPCWD was detected by IHC in the tracheobronchial lymph node. This
vast distribution of infectivity in the host, together with a high
stability of prions in the environment [27, 28, 29] can explain why
CWD is known as the most contagious prion disease, with a prevalence
of up to 30 per cent in free-ranging herds or 90 per cent in captive
herds [6, 30] and we should be prepared for detecting additional CWD
cases in the Norwegian cervid population.

Norway has a particular responsibility to manage and protect the last
remnant of the wild tundra reindeer in Europe, and the detection of
CWD in one of these sub-populations is of great concern. Efforts are
being made to reduce the migration of reindeer from Nordfjella to
neighboring sub-populations and known migration paths are being
monitored. Measures such as intensified nationwide CWD surveillance
are being planned by the Norwegian Food Safety Authority and the
Norwegian Environment Agency.

*Surveillance for CWD in Europe has been limited. In Norway,
approximately 2200 cervids have been tested from 2004 to 2015, of
which only 10 were free-ranging reindeer, but none were from the
Nordfjella area. The small number of wild reindeer tested reflects
that the chances of a sick animal in such remote areas being observed,
reported and submitted for testing are small. The European Food Safety
Authority (EFSA) stated that the occurrence of CWD could not be
excluded in cervids in Europe, "especially in remote and presently
unsampled areas" (EFSA journal 2010). Because of the limitation of the
surveillance program in cervids, it is not possible to exclude that
CWD has been present in Norway or Europe for decades without being
detected until now. This assumption is strengthened by the discovery,
at the time of writing of this paper, of 2 additional CWD cases in
moose in Norway, originating from a region situated about 300 km [186
miles] from the Nordfjella area where the CWD infected reindeer was
found. *The prevalence, epidemiology and implications of CWN in
Norwegian and European cervids remain to be determined.*

CWD is enzootic in multiple regions in North America and unfortunately
the disease is spreading. To our knowledge, this is the 1st case
report of CWD in Europe and the 1st case of the disease naturally
occurring in reindeer worldwide. The origin, prevalence, and incidence
of CWD in Norway are currently not known, but being investigated. [end
of clipped discussion from article.)

However, It does not look like an investigation, so much as it looks
like a slaughter or perhaps a rush to judgment.

Appreciation to my ProMED-mail colleague AS for the article. - Mod.TG

A HealthMap/ProMED-mail map can be accessed at:
<http://healthmap.org/promed/p/107>.]

[See Also:
2016
---
Chronic wasting disease, cervid - Europe (02): (Norway) moose
http://promedmail.org/post/20160614.4276448
Chronic wasting disease, cervid - Europe: (Norway)
http://promedmail.org/post/20160410.4149651]
.................................................sb/as/tg/ec/sh

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That stinks for Norway. Not only hat this disease has found its way to their herd - but also the infighting between the various hunting groups about the severity of the disease, and their fighting with the agencies in charge of managing wildlife there.  If MN is any indication, there doesn't appear to be any agreement over how much of a threat CWD is to the herd or hunters - or what if anything should be done to contain or eradicate it.

 

What is interesting from that article is the reference to Wyoming's CWD problem, and the 10% annual herd decline that is attributed to it. Many of the arguments I've read from people who are against what the MN DNR is doing in Zone 3 claim that CWD doesn't have a negative long term impact on a herd.

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