The Chronic Wasting Disease (CWD) is a Transmissible Spongiform Encephalopathy (TSE) or prion disease of natural transmission affecting cervids. Prion diseases are fatal neurodegenerative diseases and are characterized by the accumulation of an abnormal isoform and partially resistant to the enzymatic digestion of the cellular prion protein (PrPc), usually designated by PrPres or prion and, because of its conformation, it is very resistant to inactivation procedures used on conventional infectious agents.
Unlike the epidemic Bovine Spongiform Encephalopathy (BSE) epidemic, related to animal feedstuffs contaminated by prion-infected meat and bone meal, and whose control has been feasible with the ban on this practice, CWD is endemic and difficult to eradicate. So the study of susceptibility / resistance the cervid population to CWD is very important to define the risk of dissemination and development of the disease.
The recent identification of CWD in Norway points to the hypothesis that cervids population in Europe could be at risk for TSEs and a potential prion reservoir, as it occurs in other diseases, threatening the livestock and public health. In these species, the susceptibility / resistance to prion diseases are also influenced by the polymorphisms in the prnp gene, so the characterization of the prnp genotypic profile in cervids, as well as the PrPres survey and the georeferencing of TSE affected farms will contribute to delineate if there is a risk of dissemination of CWD in Portugal.
Thus, we propose to carry out a risk analysis for a potential occurrence of CWD in Portugal through: a) Sampling of risk cervids for detection of PrPres in lymphoid and / or brainstem tissues; B) Prnp genotyping in cervids; C) Identification of risk factors;
We expect: i) To determine the prnp genetic variability in the cervidae population; ii) Definition if there is genetic susceptibility / resistance to CWD; iii) Definition of the risk of exposure of the cervid population in Portugal to prions; iv) increase CWD awareness among stakeholders.
A more in-depth knowledge of these aspects may contribute to answering many of the questions that remain open regarding this progressive and fatal neurodegenerative disease. These new data, which will be disseminated within a collaborative work platform associated with a database, will be essential for the design of programs for the TSE control and prevention.