procedures-for-identifying-infectious-prions-after-passage-through

Procedures for Identifying Infectious Prions After Passage Through the Digestive System of an Avian Species

Infectious prion (PrPRes) material is likely the cause of fatal, neurodegenerative transmissible spongiform encephalopathy (TSE) diseases1. Transmission ...

USDA

Pigmentations of the oral cavity are commonly noted in clinical practice and may have physiologic, non-physiologic, or pathologic etiologies. The most common non-physiologic localized pigmentation is the amalgam tattoo; another, less common, non-physiologic pigmentation is the graphite tattoo. Graphite tattoos may easily be confused with amalgam tattoos but have only infrequently been reported in the literature.

Use of a subepithelial connective tissue graft to treat an area pigmented with graphite.

Deposition of prions into the environment by infected animals may contribute to transmission and spread of chronic wasting disease (CWD) among free-ranging cervids, and identification of such environmental sources may provide an avenue for managing CWD. We evaluated the role that wallow use by elk (Cervus elaphus) may play in CWD transmission by monitoring wallows with animal-activated cameras throughout their period of use. We monitored 39 wallows from 5 August 2005 to 14 October 2005. Elk visited 20 sites; we recorded 22 events when only male elk wallowed and 374 additional events when male and female elk had naso-oral contact with wallow contents. Because wallows are foci of male elk activity, behaviors at wallows could potentially contribute to the maintenance and transmission of CWD. Our findings, however, suggest that because wallows are only used an average of one or two times a season they may not be important in CWD transmission. The data also suggest that mineral licks could be more important in CWD transmission because they were used more frequently and by three species that contract CWD.

Elk use of wallows and potential chronic wasting disease transmission.

Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy (TSE) of Rocky Mountain elk in North America. Recent studies suggest that tissue and blood mineral levels may be valuable in assessing TSE infection in sheep and cattle. The objectives of this study were to examine baseline levels of copper, manganese, magnesium, zinc, selenium, and molybdenum in the brains of Rocky Mountain elk with differing prion genotypes and to assess the association of mineral levels with CWD infection. Elk with leucine at prion position 132 had significantly lower magnesium levels than elk with 2 copies of methionine. Chronic wasting disease-positive elk had significantly lower magnesium than control elk. The incorporation of manganese levels in addition to magnesium significantly refined explanatory ability, even though manganese alone was not significantly associated with CWD. This study demonstrated that mineral analysis may provide an additional disease correlate for assessing CWD risk, particularly in conjunction with genotype.

Increased risk of chronic wasting disease in Rocky Mountain elk associated with decreased magnesium and increased manganese in brain tissue.

Avian scavengers, such as American crows (Corvus brachyrhynchos), have potential to translocate infectious agents (prions) of transmissible spongiform encephalopathy (TSE) diseases including chronic wasting disease, scrapie, and bovine spongiform encephalopathy. We inoculated mice with fecal extracts obtained from 20 American crows that were force-fed material infected with RML-strain scrapie prions. These mice all evinced severe neurological dysfunction 196-231 d postinoculation (x =198; 95% CI: 210-216) and tested positive for prion disease. Our results suggest a large proportion of crows that consume prion-positive tissue are capable of passing infectious prions in their feces (ˆp=1.0; 95% CI: 0.8-1.0). Therefore, this common, migratory North American scavenger could play a role in the geographic spread of TSE diseases.

Prion remains infectious after passage through digestive system of American crows (Corvus brachyrhynchos).

Mechanisms for the spread of transmissible spongiform encephalopathy diseases, including chronic wasting disease (CWD) in North American cervids, are incompletely understood, but primary routes include horizontal and environmental transmission. Birds have been identified as potential vectors for a number of diseases, where they ingest or are exposed to infected material and later shed the disease agent in new areas after flying substantial distances. We recently identified American crows (Corvus brachyrhynchos) as having the potential to translocate infectious prions in their feces. Our results suggest that this common, migratory North American scavenger is capable of translocating infectious prions to disease-free areas, potentially seeding CWD infection where no other initial source of pathogen establishment is forthcoming. Here we speculate on the role avian scavengers, like American crows, might play in the spatial dissemination of CWD. We also consider the role mammalian scavengers may play in dispersing prions.

Article	Year
Use of a subepithelial connective tissue graft to treat an area pigmented with graphite. Journal of periodontology\| PubMed ID: 16171450	2005
Elk use of wallows and potential chronic wasting disease transmission. Journal of wildlife diseases\| PubMed ID: 17984281	2007
Increased risk of chronic wasting disease in Rocky Mountain elk associated with decreased magnesium and increased manganese in brain tissue. Canadian journal of veterinary research = Revue canadienne de recherche vétérinaire\| PubMed ID: 20357959	2010
Prion remains infectious after passage through digestive system of American crows (Corvus brachyrhynchos). PloS one\| PubMed ID: 23082115	2012
Could avian scavengers translocate infectious prions to disease-free areas initiating new foci of chronic wasting disease? Prion\| PubMed ID: 23822910	2013

Gregory E Phillips

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