Chronic wasting disease (CWD) is a prion disease that primarily affects cervids, but there have been concerns about its potential to infect humans. New data from the National Institute of Allergy and Infectious Diseases (NIAID) suggests that there is a substantial species barrier preventing the transmission of CWD to humans.
Healthy human cerebral organoids were exposed to high concentrations of CWD inocula from white-tailed deer, mule deer, and elk for 7 days. Despite this prolonged exposure, the organoids remained uninfected with CWD for up to 6 months. This suggests that there is a strong species barrier preventing the transmission of CWD to humans.
In contrast to CWD, there have been cases of other prion diseases, such as bovine spongiform encephalopathy, transmitting to humans. These cases have resulted in the emergence of variant Creutzfeldt-Jakob disease (CJD), which is universally fatal. However, the study by NIAID and Rocky Mountain Laboratories indicates that CWD does not have the same zoonotic potential as other prion diseases.
Recent reports have raised questions about the possibility of CWD prions infecting humans. A case presented at the American Academy of Neurology annual meeting described a 72-year-old man who had consumed meat from a CWD-infected deer population and experienced rapid-onset confusion and aggression. However, detailed prion protein characterization is necessary to definitively rule out CWD in such cases.
While the study provides valuable insights into the transmission of CWD to humans, there are limitations to consider. The researchers used human cerebral organoids as a model, which may not fully replicate the complex environment of the human brain. Additionally, the study only focused on short-term exposure to CWD inocula, and further research is needed to assess the long-term effects.
The data from the NIAID study suggest that there is a significant species barrier preventing the transmission of CWD from cervids to humans. While the possibility of CWD crossing into humans cannot be completely ruled out, the findings provide reassurance that the risk of transmission is low. Further research is necessary to fully understand the zoonotic potential of CWD and to ensure public health safety.
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