Tuesday, December 26, 2023

USGS Update: The Continued Spread Of CWD In North America



#17,836

In the summer of 2019 we looked at the worrisome spread of Chronic Wasting Disease (CWD) in Deer and Elk (see mBio: Chronic Wasting Disease in Cervids: Implications For Prion Transmission To Humans & Other Animalsboth in the United States and Canada. 

That mBio article noted the spread of CWD (in 2000, only 5 States reported the disease), and its zoonotic potential.  While human cases have not been identified, it may take years for the disease to manifest in humans, and even then diagnosing it could be challenging.  

The authors (including Michael T. Osterholm) wrote:

Available data indicate that the incidence of CWD in cervids is increasing and that the potential exists for transmission to humans and subsequent human disease. Given the long incubation period of prion-associated conditions, improving public health measures now to prevent human exposure to CWD prions and to further understand the potential risk to humans may reduce the likelihood of a BSE-like event in the years to come.

There is precedence, as other prior diseases have (very rarely) been transmitted from animals to humans, including vCJD (Variant Creutzfeldt-Jakob disease), which the CDC describes as:

Variant Creutzfeldt-Jakob disease (vCJD) is a prion disease that was first described in 1996 in the United Kingdom. There is now strong scientific evidence that the agent responsible for the outbreak of prion disease in cows, bovine spongiform encephalopathy (BSE or ‘mad cow’ disease), is the same agent responsible for the outbreak of vCJD in humans.

Despite the lack of confirmed CWD human infections, some key points from the CDC include:

  • If CWD could spread to people, it would most likely be through eating of infected deer and elk. 
  • To date, there is no strong evidence for the occurrence of CWD in people, and it is not known if people can get infected with CWD prions.
  • Hunters must consider many factors when determining whether to eat meat from deer and elk harvested from areas with CWD, including the level of risk they are willing to accept.
  • In areas where CWD is known to be present, CDC recommends that hunters strongly consider having those animals tested before eating the meat.

This month the USGS has updated their CWD Map (see below), which should be of interest to anyone who hunts deer or elk, or consumes their meat, from these regions. 













Chronic wasting disease (CWD) has been detected in 32 US states and four Canadian provinces in free-ranging cervids and/or commercial captive cervid facilities. CWD has been detected in free-ranging cervids in 32 states and three provinces and in captive cervid facilities in 18 states and three provinces.

Also in 2019, in the CDC: The 8 Zoonotic Diseases Of Most Concern In The United States, we looked at a newly published 68-page One Health Zoonotic Disease Prioritization report, that identified the top 56 threats to the United States.

https://www.cdc.gov/onehealth/pdfs/us-ohzdp-report-508.pdf
CWD placed #10 on their list, coming in well ahead of Ebola, Nipah, Monkeypox and MERS-CoV. 

While the risk is uncertain, the CDC offers the following advice to hunters:
To be as safe as possible and decrease their potential risk of exposure to CWD, hunters should take the following steps when hunting in areas with CWD:
  • Do not shoot, handle or eat meat from deer and elk that look sick or are acting strangely or are found dead (road-kill).
  • When field-dressing a deer:
    • Wear latex or rubber gloves when dressing the animal or handling the meat.
    • Minimize how much you handle the organs of the animal, particularly the brain or spinal cord tissues.
    • Do not use household knives or other kitchen utensils for field dressing.
  • Check state wildlife and public health guidance to see whether testing of animals is recommended or required. Recommendations vary by state, but information about testing is available from many state wildlife agencies.
  • Strongly consider having the deer or elk tested for CWD before you eat the meat.
  • If you have your deer or elk commercially processed, consider asking that your animal be processed individually to avoid mixing meat from multiple animals.
  • If your animal tests positive for CWD, do not eat meat from that animal.

For more information you may wish to visit the USDA's: Cervids: Chronic Wasting Disease website.