03559nas a2200373   4500008004100000022004700041245013800088210006900226250001000295300001000305490000600315520235000321653001202671653003102683653002202714653002302736653002102759653003802780653001002818653003502828653002902863653000902892653002102901653002502922653002402947653002102971653006702992100001503059700001903074700001503093700001703108700001603125856004403141       2009                        eng d  a1932-6203 (Electronic) 1932-6203 (Linking)00aDetection of sub-clinical CWD infection in conventional test-negative deer long after oral exposure to urine and feces from CWD+ deer0 aDetection of subclinical CWD infection in conventional testnegat  a40151  ae79900 v43 aBACKGROUND: Chronic wasting disease (CWD) of cervids is a prion disease distinguished by high levels of transmissibility, wherein bodily fluids and excretions are thought to play an important role. Using cervid bioassay and established CWD detection methods, we have previously identified infectious prions in saliva and blood but not urine or feces of CWD+ donors. More recently, we identified very low concentrations of CWD prions in urine of deer by cervid PrP transgenic (Tg[CerPrP]) mouse bioassay and serial protein misfolding cyclic amplification (sPMCA). This finding led us to examine further our initial cervid bioassay experiments using sPMCA. OBJECTIVES: We sought to investigate whether conventional test-negative deer, previously exposed orally to urine and feces from CWD+ sources, may be harboring low level CWD infection not evident in the 19 month observation period. We further attempted to determine the peripheral PrP(CWD) distribution in these animals. METHODS: Various neural and lymphoid tissues from conventional test-negative deer were reanalyzed for CWD prions by sPMCA and cervid transgenic mouse bioassay in parallel with appropriate tissue-matched positive and negative controls. RESULTS: PrP(CWD) was detected in the tissues of orally exposed deer by both sPMCA and Tg[CerPrP] mouse bioassay; each assay revealed very low levels of CWD prions previously undetectable by western blot, ELISA, or IHC. Serial PMCA analysis of individual tissues identified that obex alone was positive in 4 of 5 urine/feces exposed deer. PrP(CWD) was amplified from both lymphoid and neural tissues of positive control deer but not from identical tissues of negative control deer. DISCUSSION: Detection of subclinical infection in deer orally exposed to urine and feces (1) suggests that a prolonged subclinical state can exist, necessitating observation periods in excess of two years to detect CWD infection, and (2) illustrates the sensitive and specific application of sPMCA in the diagnosis of low-level prion infection. Based on these results, it is possible that low doses of prions, e.g. following oral exposure to urine and saliva of CWD-infected deer, bypass significant amplification in the LRS, perhaps utilizing a neural conduit between the alimentary tract and CNS, as has been demonstrated in some other prion diseases.10aAnimals10aBiological Assay / methods10aBlotting, Western10aBrain / metabolism10aDeer / *genetics10aEnzyme-Linked Immunosorbent Assay10aFeces10aImmunohistochemistry / methods10aLymph Nodes / metabolism10aMice10aMice, Transgenic10aNeurons / metabolism10aPrions / metabolism10aProtein Isoforms10aWasting Disease, Chronic / *diagnosis / *transmission / *urine1 aHaley, N J1 aMathiason, C K1 aZabel, M D1 aTelling, G C1 aHoover, E A  uhttps://notifylibrary.org/reference/627