Lab hints CWD prions may cross species in primates, but human risk unclear

A Science Advances study in 18 cynomolgus macaques found limited prion seeding in the brain and spleen of some animals after exposure to CWD prions; standard tests often failed to detect prions, while highly sensitive PMCA and RT-QuIC assays detected low-level activity. While some macaques developed signs consistent with prion disease, the study does not prove human infection or efficient transmission, and researchers caution that extrapolating to humans is not straightforward. The findings suggest the macaque species barrier may not be absolute under experimental conditions and highlight the need for longer follow-up, better testing, and vigilant surveillance in CWD-endemic areas.