Detection of Chronic Wasting Disease Prions in Raw, Processed, and Cooked Elk Meat, Texas, USA

Abstract

We describe chronic wasting disease (CWD) prion detection in raw and cooked meat from a CWD-positive elk. We found limited zoonotic potential in CWD prions from those meat products. Nonetheless, risk for transmission to humans is still unclear, and monitoring of circulating and emerging CWD prion strains for zoonotic potential is warranted.

Keywords: BSE; CJD; CWD; Chronic wasting disease; Creutzfeldt-Jakob disease; Texas; United States; bovine spongiform encephalopathy; prions and related diseases.

Figure 1

Flowchart of experimental strategy to detect chronic wasting disease prions in raw, processed, and cooked elk meat. We sampled ham, boneless steak, sausage, and hamburger meat from an elk that tested positive for chronic wasting disease. We homogenized raw meat samples and samples of meat cooking by grilling or boiling. We then tested homogenates of raw and cooked meat and the remnant water used in the boiling procedure by PMCA using elk and human substrates. PMCA, protein misfolding cyclic amplification.

Figure 2

Western blot of PMCA used for detection of chronic wasting disease prions in raw, processed, and cooked elk meat. A) Representative PMCA data of the different samples tested. The panels depict the results obtained in 3 PMCA rounds of 1 of the replicates conducted in this analysis. All samples were treated with proteinase K, except for PrP^C that was used as a control for antibody activity and electrophoretic mobility. Numbers at the right depict molecular weight markers. B) Summary of the PMCA detection data in both replicates for raw, grilled, and boiled meats and for the water used in the boiling process. PMCA, protein misfolding cyclic amplification; PrP^C, cellular prion protein; R, round.

Figure 3

Western blot of PMCA to evaluate zoonotic potential of CWD-containing meats in a study of chronic wasting disease prions in raw, processed, and cooked elk meat. A) Ham; B) boneless steak; C) cutlets; D) hamburger; E) jerky; F) sausage; G) filets; H) chili meat; I) positive control; J) negative control. We evaluated raw, processed, and cooked meat from a CWD-positive elk for the ability to misfold the human prion protein in a single PMCA round. All samples were treated with proteinase K. The analysis depicts samples frozen before PMCA, or sonicated and submitted to PMCA. PBS and scrapie prions were used as negative controls for human PMCA reactions, and BSE and an elk CWD isolates were used as positive controls. Numbers at the left depict molecular weight markers. BSE, bovine spongiform encephalopathy; CWD, chronic wasting disease; F, frozen; PBS, phosphate-buffered saline; PMCA, protein misfolding cyclic amplification; S, sonicated.