Distribution of the misfolded isoform of the prion protein in peripheral tissues and spinal cord of Rocky Mountain elk (Cervus elaphus nelsoni) with naturally occurring chronic wasting disease.

Chronic wasting disease (CWD) is an infectious transmissible spongiform encephalopathy of cervids associated with the presence of a misfolded prion protein (PrPCWD). Progression of PrPCWD distribution has been described using immunohistochemistry and histologic changes in a single section of brain stem at the level of the obex resulting in scores from 0 (early) to 10 (terminal) in elk with naturally occurring CWD. Here we describe the spread and distribution of PrPCWD in peripheral tissues and spinal cord in 16 wild and 17 farmed Rocky Mountain elk (Cervus elaphus nelsoni) with naturally occurring CWD and correlate these findings with obex scores. Spinal cord and approximately 110 peripheral tissues were collected, processed, stained with hematoxylin and eosin, and immunolabeled with the anti-prion protein monoclonal antibody F99/97.6.1. The medial retropharyngeal and tracheobronchial lymph nodes were the first tissues to accumulate PrPCWD, followed by other lymphoid tissues, myenteric plexus, spinal cord, and finally tissues outside of the lymphatic and neural systems. However, the only significant histological lesion observed was mild spongiform encephalopathy in the dorsal column of the lower spinal cord in elk with an obex score of ≥9. Initial exposure to CWD prions may be through the respiratory system and spread appears to occur primarily via the autonomic nervous system. Therefore, we suggest using obex scores as a proxy for stage of disease progression and verifying with key peripheral tissues.

Detection of protease-resistant cervid prion protein in water from a CWD-endemic area.

Chronic wasting disease (CWD) is the only known transmissible spongiform encephalopathy affecting free-ranging wildlife. Although the exact mode of natural transmission remains unknown, substantial evidence suggests that prions can persist in the environment, implicating components thereof as potential prion reservoirs and transmission vehicles.(1-4) CWD-positive animals may contribute to environmental prion load via decomposing carcasses and biological materials including saliva, blood, urine and feces.(5-7) Sensitivity limitations of conventional assays hamper evaluation of environmental prion loads in soil and water. Here we show the ability of serial protein misfolding cyclic amplification (sPMCA) to amplify a 1.3 x 10(-7) dilution of CWD-infected brain homogenate spiked into water samples, equivalent to approximately 5 x 10(7) protease resistant cervid prion protein (PrP(CWD)) monomers. We also detected PrP(CWD) in one of two environmental water samples from a CWD endemic area collected at a time of increased water runoff from melting winter snow pack, as well as in water samples obtained concurrently from the flocculation stage of water processing by the municipal water treatment facility. Bioassays indicated that the PrP(CWD) detected was below infectious levels. These data demonstrate detection of very low levels of PrP(CWD) in the environment by sPMCA and suggest persistence and accumulation of prions in the environment that may promote CWD transmission.

Assistive devices: utilization by children.

The use of assistive devices by children has become widespread and has been supported financially by insurance carriers and governments. However, there has been little evaluation of the utilization of these devices. To determine utilization of, satisfaction with, and perceived value of the aid, an independent evaluator contacted 502 families who had used a provincial government funding program to obtain an assistive device. High levels of use, satisfaction, and perceived value were reported, indicating that a decentralized funding program can provide aids effectively.