Prion diseases iatrogenic

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

Subclinical or carrier states of prion disease have major implications for public health, most notably iatrogenic transmission from apparently healthy individuals. The existence of subclinical prion infections also raise the possibility that other species (such as sheep, pigs and poultry), exposed to BSE prions by contaminated feed, might be able to develop subclinical carrier states. Given that BSE prions are pathogenic in a wide variety of species, and that the strain characteristics of BSE prions are retained upon transmission to new species, it must be considered possible, if not probable, that BSE in animals other than cattle will retain pathogenicity for humans. 

Fig. 3. Classification of human prion diseases. Sporadic the transformation from PrPc (circle) to PrPSc (square) occurs without apparent cause. Familial a point mutation ( ) is thought to facilitate the transformation. Infectious the transformation arises via PrPSc which acts as a template. The kinetic equations are defined by Eigen (1996). The infectious form includes kuru, iatrogenic CJD (iCJD), variant CJD (vCJD first reported in 1996), bovine spongiform encephalopathy (BSE first reported in 1985), and scrapie. In the nucleation-dependent model, monomeric PrPc and PrPSc are in chemical equilibrium.

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. 

CNS Pathogenesis of Sporadic, Familial, and Iatrogenic Prion Diseases... 

Examples for the different causes of a TSE disease are provided by the various subforms of CJD in humans. CJD was first observed in 1920, and remains one of the best analyzed prion diseases. Classic CJD is divided into three subforms according to the pathogenic mechanism with iatrogenic CJD patients are infected, for example, through administration of contaminated human growth hormone or transplantation of contaminated dma mater. In addition, the disease can be passed on by contaminated EEG needles in individual cases. In total, more than... 

Known human prion diseases are Creutzfeldt-Jacob disease (CJD), Gerstmann-Straussler-Schienker syndrome (GSS) and fatal familial insomnia (FFI). GSS and FFI are inherited, whereas CJD may be inherited, sporadic or infectious. Another infectious form of CJD (iatrogenic CJD) arises from inadequately sterilized surgical instruments, dura mater grafts, and from human growth hormone isolated from cadavers. Kuru is a classical example of an infectious human prion disease transmitted by the ritual cannibalism of human brains, this disease was formerly common in the Fore tribe of New Guinea. 

Prion diseases The current state of iatrogenic prion disease and how to navigate this risk have recently been reviewed [166, 167 ]. 

Barrenetxea G. Iatrogenic prion diseases in humans an update. Eur J Obstet G)fnecol Reprod Biol 2012 165(2) 165-9. 

---