NDA Urges Deer Hunters to Consider New CWD Report With Caution

April 18, 2024 By: NDA Staff

A sketchy online report from neurologists at the University of Texas Health Science Center, in the journal Neurology, is getting attention and causing confusion about the human health implications of chronic wasting disease in deer. Caution and accuracy are critical when examining the question of CWD and human health. Until more information about this report becomes available, we urge deer hunters to consider this new report cautiously.

First, we emphasize: Nothing about this new report changes current knowledge or guidance on CWD in deer. The evidence remains strong that CWD in deer and elk is not causing disease among hunters who consume infected animals. Because scientific certainty is not 100%, and prion diseases are still not fully understood, experts continue to recommend CWD testing of all deer harvested in known CWD areas, and avoiding consumption of CWD-positive venison to minimize risk.

The brief report focuses on a 72-year-old man who died in 2022 of Creutzfeldt-Jakob Disease (CJD), a human disease that is similar to CWD in deer but never definitively connected through causation. We aren’t told where he lived. The man reportedly had a friend who also died “recently” of CJD. We are given scant details about any of this, but according to the report, both men had “…a history of consuming meat from a CWD-infected deer population.” 

This is not the same as eating meat from a CWD-infected animal. Just because CWD is in the population does not mean the patient ate a sick deer. In many CWD zones, prevalence rates are low and the vast majority of deer are healthy. If either of these patients in fact consumed CWD-positive venison, the evidence for this is not presented or even hinted at in the paper. 

CJD, which affects about one in every 1 million Americans annually and is most common in people over age 55, is known to be sporadic and to appear in localized clusters. No previously investigated cluster has been found to have links to CWD in deer. In fact, experts have looked for patterns or clusters among hunters in the oldest CWD zones without finding any. While the odds of two acquaintances both having CJD are slim, it is not impossible. Just because it is unlikely does not prove a connection to CWD, especially with no supporting evidence for that conclusion other than circumstance.

“Any assertion that CWD has spilled over into humans needs a full and comprehensive diagnostic investigation,” said Dr. Krysten Schuler, wildlife disease ecologist with the Cornell Wildlife Health Lab. “The implications of such a finding would have huge implications for wildlife and the hunting community.”

Unfortunately, the new report does not suggest a comprehensive investigation. The authors admit they are only speculating about a connection between CWD and CJD.

“Although causation remains unproven,” they write, “this cluster emphasizes the need for further investigation into the potential risks of consuming CWD-infected deer and its implications for public health.” 

We agree about further investigation, and many experts and institutions are doing just that. We hope they are more cautious and responsible in how they present their findings. Though these authors raise the question of whether CWD is to blame in their cases, they cannot answer that question with the information they possess. Thus, they unnecessarily cause alarm and fear – and triggered irresponsible news media coverage – without solid evidence justifying the alarm.

Numerous studies and experiments have reinforced the idea of a strong species barrier preventing humans from acquiring CWD from deer. An extensive, long-term CDC study of hunters in three CWD states did not find the human-variant disease at levels higher than in the general American population. 

There has never been a proven case of CWD spillover into humans, and that is still true after this report from the University of Texas Health Science Center in the journal Neurology. We hope the authors provide more details, evidence, or a clarification of their comments soon. The implications are just too important to treat this subject so casually.