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Chronic Wasting Disease overview
Methods of fighting prion diseases
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Introduction to CWD;
Chronic Wasting Disease (CWD) is a fatal neuro-degenerative, transmissible spongiform encephalopathy (TSE) of the family Cervidae (Hamir, et.al., 2006). The family Cervidae includes mule deer, Odocolileus hemionus, white-tailed deer, Odocolileus virginianus, Rocky Mountain elk, Cervus elaphus nelsoni, and moose, Alces alces shirasi, among others (Sigurdon & Aguzzi, 2007). CWD is a prion disease, meaning it is a protein caused infection, that occurs naturally in the deer family (Song & Lawson, 2009). This protein is suspected to be an abnormal isoform (PrPSc) of the naturally occurring host prion protein (PrPC) (Blanchong, et. Al., 2009). Bovine spongiform encephalopathy (BSE), mad cow disease, is a similar prion effecting cattle as CWD affects Cervidae. Although, scientists are not sure of transmission route it is suspected that CWD is transmissible and infectious through direct contact with infected individuals or through environmental contamination (Song & Lawson, 2009). Tests have been performed showing susceptibility of altered mice to oral transmission, mimicking the suspected route of entry, and the incubation appears slower but lasts longer with oral infection (Trifilo, et.al., 2007). The approximate time from the initial infection to death is three years.
History of CWD;
The origin of CWD has yet to be determined (Sigurdson & Aguzzi, 2007). The infection was first noted in 1967 at a captive mule deer research facility. In 1978 pathologists recognized the TSE type brain lesions, also that CWD presented as a prion disease by the neuronal perikaryonic vacuoles, the accumulation of aggregated prion protein and prion infectivity in the brain. In the late 1970s and early 1980s the infection w...
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... to 225SF (Sigurdson & Aguzzi, 2007). Elk expressing codon 132MM and 132ML were seen to be a high percentage of the infected while elk expressing 132LL showed resistance to CWD infection for at least four years. In Wisconsin white-tailed deer showed reduced susceptibility with the expression of codons G966S and Q95H.
Conclusion;
White-tailed deer, along with the rest of the Cervidae family, are facing a possible epidemic. Although the disease has not spread over the entire range CWD is efficiently transmitted between individuals. CWD is to the best of our knowledge 100% fetal and incubation can take a few years allowing for many possible transmissions. There also at this time is no form of vaccine or treatment for infected cervids. Despite efforts being put forth to control CWD, being a free-range family of animals proves control to be extremely difficult.
When people talk about deer, they are commonly talking about the North American Whitetail. That is because they are so prevalent in this country. They can be found in every state in the US. The only place where you will not find any whitetails is in parts of Arizona and California. In most states the whitetail is very prevalent, especially in the northeast. They are one of the most hunted animals in this area, particularly in Pennsylvania and Michigan. Despite the amount they are hunted, both in and out of season, you can not drive more than a few miles out of the towns without seeing one that was hit by a car. The deer population in this area just keeps growing. It is unclear what should be done to stop the over population of this beautiful creature. Perhaps different hunting seasons or longer seasons are the answer. Possibly we should focus more on the development of birth control for the female deer, or maybe repopulating wolves into the areas where the deer population is too great. Something has to be done.
The author provides information describing the deer population in parts of New Jersey; yet, he does not include any data regarding the population in the rest of the United States, nor does he include any sources of where this information was obtained. A reader may be more
The meningeal worm is also known as the brain worm, or the deer worm. It frequently infects llamas and alpacas, but can infect other species as well like moose, elk, goats, and sheep. The meningeal worm is an internal parasite that is a part of the protostrongylidae family with the definitive host being the common white tailed deer. Even though they are the host, adult meningeal worms rarely cause clinical signs of disease in the deer. The white tail deer’s tolerance to infection from these worms is actually beneficial to the parasite because the white tail deer are the only species that will allow the worm to complete their life cycle.
HIPPA COW Security Administrative Safeguard Policy/Procedure Workgroup. (2006). Contingency Planning (Draft, Version 8). Wisconsin: HIPAA Collaborative of Wisconsin.
Mad Cow Disease, scientifically referred to as (BSE) Bovine Spongiform Encephalopathy, is a disease that affects those humans who eat the meat from infected cows. Mad Cow Disease is one of several fatal brain diseases called (TSE) Transmissible Spongiform Encephalopathy. (USDA) There was evidence of a new illness resembling the sheep disease scrapie. It was technically named BSE but quickly acquired the mad cow tag because of the way infected cattle behave. (CNN) In 1997, there was an award given to Stanley Prusiner, for concluding that a distorted protein called a prion was responsible for Mad Cow Disease, noted the long incubation period made it difficult to distinguish (Bryant). Another name for Mad Cow Disease is the new variant Cruetzfeldt-Jakob Disease (vCJD), similar to the Creutzfeldt-Jakob Disease, which is a deadly brain illness that strikes about one per million per year (USDA) due to genetic or unknown causes while the vCJD is contracted from eating infected cows (USDA). Both CJD and vCJD are so similarly named because of the similar effects from the illness.
Mad cow disease is caused by prions, "weird mutant proteins that are found in brain and spinal tissue"1. Another name for mad cow disease is called bovine spongiform encephalopathy (BSE) and the definition is "a progressive neurological disorder of cattle that results from infection by an unusual transmissible agent called a prion"2. It started from what is called a prion protein then it turned into a pathogenic, and then it starts to damaged the brain of a cattle. There's another name for this disease and it's called Creutzfeldt-Jakob Disease "a form of progressive dementia characterized by loss of nerve cells and degeneration of nerve cell membranes leading to the production of small holes in the brain. It is rare, degenerative, and invariably fatal"3. This disease happen in human causing lapses in the memory, mood swings similar to depression, lack of interest and social withdrawal3. It is said that this disease has no tr...
PrP can occur in two forms- a normal cellular prion protein known as PrPc and a pathogenic misfolded conformer known as PrPsc. The abnormal PrPsc differs from the normal prion protein PrPc in both secondary and tertiary structure. PrPsc is principally rich in Beta sheet contents but PrPc is principally rich in alpha helical contents. Due to this difference of between the isoforms, prions are extremely resistant to certain decontamination systems. The Two tables below outline both human and animal diseases (2).
Thesis: The population of white-tail deer in Alabama has drastically increased over the past century causing significant damage to property and homeowners, caused by hunters being less active.
Normally, cows in Northern Europe in places such as Denmark live normal lives simply grazing on grass, and existing. However, there have been recent changes that have disrupted this normal activity. Generally the bluetongue virus (spread by Culicoides imicola, a biting midge) has been confined to Southern Europe and other places around the Mediterranean. But with the increase in temperature throughout the area, the midge has been allowed to migrate northward. This new pest is a nuisance and causes lots of difficulties to farmers in the area. When a cow contracts this disease, they usually also receive oral ulcers, salivation, stiffness, fever and eventually the inevitable- death (Merck Veterinary Manual NP). Because of the increase in temperature, midges have spread around the globe infecting livestock and creating terrible trouble for many farmers.
Deer overpopulation is a controversial topic. Some believe that deer overpopulation is not a real problem. Some may also believe the high numbers that studies show, is a scheme to give hunters an excuse to hunt without reason. The truth is that deer overpopulation is a true issue. Deer, especially the eastern whitetail deer population in these modern times, is out of control. “There are an estimated 30 million whitetail deer in the United States today. Under optimal conditions, whitetail deer populations will double every two years”(Rooney). As the numbers of whitetail deer rise, the land for them to live on decreases. This may lead to deer walking on roads and causing accidents.
White tailed deer are the largest game animal in North America. This is due to their over abundance and annoyance to farmers. An average of 300000 deer are hunted down each year. A tragedy has been another 3000 are hit by cars every year. Many human efforts have been made to prevent these accidents, such as fencing and deer repellents near freeways, but many seem to think that hunting and controlling the population is the best way.
Chronic Wasting Disease is a highly transmissible, deadly neurodegenerative disease that affects cervids in North America (Belay et al., 2004; Saunders et al., 2012). There are only four types of cervid that are known to get this disease which include elk, mule deer, white-tailed deer, and moose (Chronic Wasting Disease Alliance). It has been classified has a transmissible spongiform encephalopathy (TSE), otherwise known as a prion disease (Belay et al., 2004). A prion is an irregular, pathogenic agent that causes abnormal folding of specific proteins called prion proteins. These proteins are mostly located in the brain (Chronic Wasting Disease Alliance). The abnormal folding of this protein causes neurodegenerative diseases in a variety of species including humans, sheep, cattle, and deer (Abrams et al., 2011).
Chronic obstructive pulmonary disease (COPD) is preventable disease that has a detrimental effects on both the airway and lung parenchyma (Nazir & Erbland, 2009). COPD categorises emphysema and chronic bronchitis, both of which are characterised by a reduced maximum expiratory flow and slow but forced emptying of the lungs (Jeffery 1998). The disease has the one of the highest number of fatalities in the developed world due to the ever increasing amount of tobacco smokers and is associated with significant morbidity and mortality (Marx, Hockberger & Walls, 2014). Signs and symptoms that indicate the presence of the disease include a productive cough, wheezing, dyspnoea and predisposing risk factors (Edelman et al., 1992). The diagnosis of COPD is predominantly based on the results of a lung function assessment (Larsson, 2007). Chronic bronchitis is differentiated from emphysema by it's presentation of a productive cough present for a minimum of three months in two consecutive years that cannot be attributed to other pulmonary or cardiac causes (Marx, Hockberger & Walls, 2014) (Viegi et al., 2007). Whereas emphysema is defined pathologically as as the irreversible destruction without obvious fibrosis of the lung alveoli (Marx, Hockberger & Walls, 2014) (Veigi et al., 2007).It is common for emphysema and chronic bronchitis to be diagnosed concurrently owing to the similarities between the diseases (Marx, Hockberger & Walls, 2014).
In the last decade, from the Rockies to New England and the Deep South, rural and suburban areas have been beset by white-tailed deer gnawing shrubbery and crops, spreading disease and causing hundreds of thousands of auto wrecks. But the deer problem has proved even more profound, biologists say. Fast-multiplying herds are altering the ecology of forests, stripping them of native vegetation and eliminating niches for other wildlife. ' 'I don 't want to paint deer as Eastern devils, ' ' said Dr. McShea, a wildlife biologist associated with the National Zoo in Washington, ' 'but this is indicative of what happens when an ecosystem is out of whack. ' ' The damage is worse than anyone expected, he and other scientists say. Higher deer densities have affected growth, survival, and reproduction of many plant species which have aesthetic, economic or ecological value. In some cases, many species of trees have also been shown to have reduced growth as a result of high deer density (Environmental Benefits of Hunting, 1). Deer prefer certain plant species over others and frequently feed on economically valuable tree species. For example, they prefer oak and sugar maple seedlings, as well as acorns, over less palatable species like American Beech and striped maple. Thus, less marketable species are more likely to survive to maturity,
Years ago, killing animals for food was part of the average man’s everyday life. While, now a days, hunting is questioned by many across the world because it is commonly viewed as a recreational activity. Many residents have a problem with the dangers that come with hunting. Not to mention, as time goes on, society seems to feel differently about animals and how they should be treated. One of the biggest debates is the harvest of white tailed deer. All over the United States, white tailed deer thrive because of the few predators that feast upon them and the large forests and habitats that these deer can flourish in. However, as buildings and subdivisions pop up left and right decreasing the white tailed deer natural habitat, the debate grows stronger. The heart of the debate is centered around ethical issues, human and deer conflicts, safety, and the benefits hunting has on the economy.