A new study of prion diseases, using a human cerebral organoid model, suggests there is a substantial species barrier preventing transmission of chronic wasting disease (CWD) from cervids—deer, elk and moose—to people.
The findings, from National Institutes of Health scientists and published in Emerging Infectious Diseases, are consistent with decades of similar research in animal models at the NIH’s National Institute of Allergy and Infectious Diseases (NIAID).
In 2019, NIAID scientists at Rocky Mountain Laboratories in Hamilton, Montana, developed a human cerebral organoid model of Creutzfeldt-Jakob Disease to evaluate potential treatments and to study specific human prion diseases.
In the new CWD study, the bulk of which was done in 2022 and 2023, the research team validated the study model by successfully infecting human cerebral organoids with human CJD prions (positive control). Then, using the same laboratory conditions, they directly exposed healthy human cerebral organoids for seven days with high concentrations of CWD prions from white-tailed deer, mule deer, elk, and normal brain matter (negative control). The researchers then observed the organoids for up to six months, and none became infected with CWD.
This indicates that even following direct exposure of human central nervous system tissues to CWD prions there is a substantial resistance or barrier to the propagation of infection, according to researchers. The authors acknowledge the limitations of their research, including the possibility that a small number of people may have genetic susceptibility that was not accounted for, and that emergence of new strains with a lesser barrier to infection remains possible. They are optimistic that the inference of these current data is that humans are extremely unlikely to contract a prion disease because of inadvertently eating CWD-infected cervid meat.
