Prion diseases acquired

Acquired human prion diseases include kuru and variant CJD 794 Prion protein polymorphism contributes genetic susceptibility to prion disease 794... 

Human prion diseases encompass the three etiological types of prion disease inherited, sporadic and acquired forms. 

Acquired human prion diseases include kuru and variant... 

The acquired prion diseases account for less than 1 % of all human prion disease cases and these include variant CJD, iatrogenic CJD (iCJD), and kum (reviewed by Will, 2003). In these cases, prion infection is either orally acquired or associated vdth accidental transmission via medical practices. Many of these latter cases involve contamination with brain tissue, which contains the highest amount of prion infectivity, from the donor host. 

Iatrogenic CJD is the second most common acquired human prion disease and these cases are the result of accidental infection due to contact with prion contaminated tissues or instruments during medical procedures (Table 29.1). The mode of prion infection include surgical equipment (e.g., surgical insd uments, depth electrodes), transplantation of human tissues (comeal, dura mater), intramuscular injections with growth hormone or gonadotrophin extracted from human pituitary tissues, or blood transfusion (reviewed by Will, 2003). The most likely source of infection is from donors with subclinical sCJD, except for the tw o transfusion-related cases that have been linked to blood donors who developed vCJD several years later (reviewed by Ironside, 2006). The incubation period in these transfusion related cases was 5 to 6 years, v hich is shorter than primary vCJD infection in humans. 

The sites of prion agent replication and spread are largely cUctated by v hether the etiology of prion disease is sporadic, familial, or acquired. For example, in sCJD and fCJD, disease initiates in, and is largely confined to, the nervous system. In... 

The immune system plays a central role in the pathogenesis of prion infection. In the acquired human prion diseases, it is the initial site of agent replication prior to entry into the nervous system but the immune system does not appear to be essential in the pathogenesis of the familial and sporadic human prion diseases. Followdng peripheral exposure to the prion agent, the immune system can amplify prion infection but, interestingly, the adaptive immune response does not play a role in the clearance of the prion agent. 

Will RG (2003) Acquired prion disease Iatrogenic CJD, variant CJD, kuiu. Br Med Bull 66 255-265. 

Creutzfeldt-Jakob disease (CJD) the most common prion disease of humans and can have a sporadic, familial or acquired etiology. 

Genetic Susceptibility to Acquired and Sporadic Human Prion Disease... 

In other acquired prion diseases, notably scrapie of sheep and variant Creutzfeldt-Jakob disease (vCJD) in humans, amino acids encoded at certain key positions in the endogenous host prion protein are strongly associated with susceptibility to prion infection [57-59]. Studies of CWD in elk, mule deer, white-tailed deer, and moose have found that similar correlations between PrP amino acid sequence and likelihood of CWD infection could exist in these species as well. 

Prions share the ability to propagate strain information with nucleic acid based pathogens, but it is unclear how they mutate and acquire fitness in the absence of this informational component. Because prion diseases occur as epidemics, understanding this mechanism is of paramount importance for implementing control strategies to limit their spread, and for evaluating their zoonotic potential. While the existence and mutability of strains persuaded early researchers that prion... 

Collinge J, Whitfield J, McKintosh E, Beck J, Mead S, Thomas DJ, Alpers MP (2006) Kuru in the 21st century-an acquired human prion disease with very long incubation periods. Lancet 367 2068-2074... 

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