Jakob Disease In Humans Biology Essay


According to the World Health Organization (W.H.O) fact sheet, no. 180, the Variant Creutzfeldt-Jakob disease (vCJD) is a rare but fatal occurrence in human beings. The organization labels the disease as a neurodegenerative condition, classified as a "Transmissible Spongiform Encephalopathy TSE" (WHO, 2011). The fatal brain disorder affects one person in a population of a million people in the world yearly; hence, is a very rare disease. According to the Centers for Disease Control and Prevention, "the median age at death for vCJD patients is 28 years, compared with 68 years for patients with classic CJD" (CDC, 2010). These statistics show that vCJD can stay in a person for quite a long time without making the carrier sick or showing profound symptoms. Some of the profound symptoms associated with the disease as it progresses include psychiatric symptoms such as depression, withdrawal and anxiety, sensory symptoms neurological abnormalities such as ataxia. The progression of the disease ultimately leads to death (Bradley, p. 1759).

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Although the Creutzfeldt-Jakob disease (CJD) first appeared in 1920, a new variant of CJD appeared in 1996 in the UK. It is possible to draw parallels and contrasts between these two diseases. They both lead to fatal progressive degeneration of brain cells leading to death. A contrast between the two diseases is that vCJD has the possibility of infecting much younger people than the other forms of CJD. In addition, transmission of the variant type of this disease can be by eating contaminated beef products and blood transfusion. Unlike CJD, vCJD has completely different symptoms and a longer survival period after the onset of symptoms, which is above one year, (an average of about 14 months) while CJD has a survival period of one year after the onset of its profound symptoms. vCJD is also characteristic of producing a rare abnormality in brain tissue referred as "florid plaques", which are rarely or not found in the other forms of CJD (CDC, 2010).

Evidence collected since its description, seems to point that a link can be established with the outbreaks of Bovine Spongiform Encephalopathy (BSE), otherwise known as "mad cow" disease with vCJD. The variant is highly linked to exposure, especially through food to a transmissible spongiform encephalopathy of cattle referred to as Bovine Spongiform Encephalopathy (BSE). Scientific proof point out that the agent that causes outbreak of the prion disease in cattle is the same agent that causes vCJD in humans. Both conditions in humans and cattle lead to fatal brain diseases caused by transmissible agents referred to as prions (proteinaceous infectious particle), which are composed of "misfolded prion proteins". Prions are the only known transmissible agents other than bacteria, parasites or fungi, considered as "pure proteins" (Bishop, Will & Manson, 2010). Research has shown that the incubation period for vCJD is around 10 years. Researchers and scientists have however not established a vaccine to deal with the disease. The prions are responsible for causing progressive brain damage and the profound symptoms characteristic of the disease. They attack the brain and kill tissues, which creates gaps in the tissues. The European Centre for Disease Prevention and Control, points out that "prions are stable and relatively resistant to proteaseas, high temperatures, UV radiation, and commonly used disinfectants" (ECDC, 2011).

According to the Food and Drug Administration, "Individuals in the UK are at a greater risk for this rare disease than are individuals elsewhere because of the previous higher risk of potential exposure to contaminated beef in the UK diet" (FDA, 2009). To support this claims, the FDA points out that statistics carried out between1995 and 2007, indicate that 165 out of the 202 individuals diagnosed worldwide are from the UK, with the US having only three cases reported. Two of the victims in the US cases had lived in the UK between these periods. The disease peaked in 1999 and started declining afterwards. However, there is a very low risk of acquiring vCJD even after consuming the infected meat, with the FDA stating that the "current risk of acquiring vCJD from eating beef and beef products appears to be negligible" (FDA, 2009).

Although the transmission of vCJD is primarily through consumption of infected cattle products, there are cases in the UK where the agent blood transfusions have been the cause of transmission of the agent. Four people infected after receiving red blood cells, had gone through the transfusion process from three donors who were vCJD carriers. However, there has been no evidence linked with the spread of the disease through personal contact such as kissing, hugging or even having sexual encounters (FDA, 2009).

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Since the main cause of the occurrence of vCJD is through the consumption of beef products, emphasis has mainly been on reducing the spread of BSE. This is through restricting importation of animals from countries that have high prevalence rates of BSE. Most Europeans countries have in the past few years increased the surveillance of BSE and placed bans of high-risk products. The other type of transmission of the disease, blood transfusion has seen enhanced actions by medical authorities to reduce the spread of prions. Restrictions on donating blood are tightly in place for individuals who lived in the UK between 1980 and 1996, when the prevalence of the disease was high. In the UK, "universal leukocyte reduction was introduced", as a preventative measure to reduce transmission of the disease through blood transfusion (Pall, 2011). The medical fraternity in the UK ensures that all infants born after 1996 receive blood plasma from outside the UK to reduce the risk of vCJd. However, research seems to suggest that the effectiveness of leukocyte reduction stands at only 42% suggesting that the risk of transmission is still considerably high, especially considering the fact that "not all prions found in the blood are cell associated" (Pall, 2011). Individuals who have received "pituitary derived hormones, dura matter, sclera or corneal grafts" from the UK are differed from donating blood in most European countries (Moiz, 2006 p. 78).

The fatality of vCJD makes it imperative to device strategies to counteract its fatal nature. It is important to note that other forms of CJD have a negligible risk rate in transmission through blood transfusion; the same is not applicable to vCJD. The fact that current data shows that four cases of transmission of the disease has taken place through blood transfusion, makes it an issue of concern (CJD, 2011). Since there is no known vaccine or treatment, the only way to reduce its infection through blood transfusion is a device that cleans the blood of the donor from the proteins responsible for causing the disease. The gist behind filtering is capturing the misfolded proteins (prions), an action that eliminates the possibility of prions aggregating in the brain. The fact that no tests exist to determine if an individual has the vCJD proteins, leads to restrictions on determining who has the prions and this increases the risk of the disease spreading. There is a high possibility that some people may be asympotomatic carriers, which means they have the prion proteins but have not developed the clinical illness. The promise that the prions filter device offers could alter this situation and reduce the likely hood of transmitting the vCJD disease through blood transfusions. The device only used once, works by capturing and removing vCJD proteins from blood by a "highly specific affinity absorbent material" that is passed through the device under the force of gravity (MacoPharma, 2009).

In conclusion, it is evident that Variant Creutzfeldt-Jakob disease is rare yet fatal disease that leads to death. Unlike other forms of CJD, it attacks much younger people, has a longer incubation period, and transmitted through consumption of beef products and blood transfusion. Taking measures against this fatal disease is emphasized and especially screening of blood from donors to reduce effectively the risk of transmission.