Cheetah Posted April 17, 2017 Share Posted April 17, 2017 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 <[email protected]> [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) moosehttp://promedmail.org/post/20160614.4276448 Chronic wasting disease, cervid - Europe: (Norway)http://promedmail.org/post/20160410.4149651] .................................................sb/as/tg/ec/sh Quote Link to comment Share on other sites More sharing options...
Getanet Posted April 17, 2017 Share Posted April 17, 2017 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. Quote Link to comment Share on other sites More sharing options...
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