Infectious Prions in Brains and Muscles of Domestic Pigs Experimentally Challenged With the BSE, Scrapie, and CWD Agents

Authors

Francisca Bravo-Risi
Fraser Brydon
Angela Chong
Kane Spicker
Justin J Greenlee
Glenn Telling
Claudio Soto
Sandra Pritzkow
Marcelo A Barria
Rodrigo Morales

Language

English

Publication Date

9-10-2025

Journal

mBio

DOI

10.1128/mbio.01800-25

PMID

40823831

PMCID

PMC12421853

PubMedCentral® Posted Date

8-18-2025

PubMedCentral® Full Text Version

Post-print

Abstract

Experimental studies suggest that animal species not previously described as naturally infected by prions are susceptible to prion diseases affecting sheep, cattle, and deer. These interspecies transmissions may generate prions with unknown host ranges. Pigs are susceptible to prions from different origins, including deer chronic wasting disease (CWD), sheep scrapie, and bovine spongiform encephalopathy (BSE). Here, we studied prions in brains and muscles from pigs previously infected with these different prion sources. Specifically, we measured the total prion protein (PrP) and PK-resistant PrP by western blot. Seeding activity in these tissues was evaluated using the protein misfolding cyclic amplification (PMCA) technique. We found that BSE-infected pigs contained substantially more seeding competent prions compared with those infected with CWD and scrapie. Moreover, the zoonotic potential of porcine-BSE prions seems to be relevant, as both brains and muscles from BSE-infected pigs induced the misfolding of the human prion protein in vitro. This study helps to understand the potential fate of naturally existing prion strains in a relevant host and calls for caution considering the co-existence between feral swine and other prion-susceptible animal species.

IMPORTANCE

Prions (PrP^Sc) are proteinaceous, infectious pathogens responsible for prion diseases. Some livestock are highly susceptible to prion diseases. These include cattle (bovine spongiform encephalopathy, BSE), sheep and goat (scrapie), and cervids (chronic wasting disease, CWD). Unfortunately, BSE has been reported to be naturally transmitted to humans and other animal species. Domestic pigs, a relevant livestock animal, have not been reported to be naturally affected by prions; however, they are susceptible to the experimental exposure to BSE, scrapie, and CWD prions. Given the widespread consumption of porcine food products by humans, we aimed to evaluate the levels of pig-derived BSE, scrapie, and CWD prions from experimentally challenged domestic pigs in brain and meat cuts (leg, cheek meat, skirt meat, and tenderloin). We detected pig-adapted prions in the brains and some muscles of these animals. Additionally, we evaluated the in vitro compatibility between pig prions and the human prion protein (as a surrogate of zoonosis). Our results show that only pig-derived BSE prions were able to induce the misfolding of the cellular human prion protein. This data highlights the consequences of prion spillovers to other animal species and their potential availability to humans.

Keywords

Animals, Brain, Encephalopathy, Bovine Spongiform, Swine, Cattle, Prions, Scrapie, Muscles, Wasting Disease, Chronic, Prion Diseases, Sheep, Sus scrofa, Humans, Deer, prion, pigs, chronic wasting disease, bovine spongiform encephalopathy, scrapie, PMCA, muscles, zoonotic infections

Published Open-Access

yes

Recommended Citation

Bravo-Risi, Francisca; Brydon, Fraser; Chong, Angela; et al., "Infectious Prions in Brains and Muscles of Domestic Pigs Experimentally Challenged With the BSE, Scrapie, and CWD Agents" (2025). Faculty, Staff and Student Publications. 6305.
https://digitalcommons.library.tmc.edu/uthgsbs_docs/6305