Report Ignites Unsubstantiated Fears Regarding CWD Transmission In Humans

Georgia has seen no cases of a deer infected with CWD.

A presentation earlier this month at the annual meeting of the American Academy of Neurology has unnecessarily reignited fear and uncertainty associated with human consumption of CWD-infected venison. Published in the journal, Neurology, the abstract stated, “The patient’s history, including a similar case in his social group, suggests a possible novel animal-to-human transmission of CWD.” While the researchers qualified their statement by citing a lack of evidence of transmission, their presentation has led to news reports with sensationalized headlines such as this one that appeared with a USA Today article: “Chronic wasting disease: Death of 2 hunters in US raises fear of ‘zombie deer.’

Before anyone gets too worked up here, we need to stop and review the facts—of CWD and this study. First, since its discovery in 1967, there has not been a single confirmed case of CWD in deer jumping to humans. If so, then why all the concern regarding potential human health implications? Simple, CWD belongs to a group of fatal brain diseases which includes mad cow disease, scrapie in sheep and Creutzfeldt-Jakob disease (CJD) in humans. Of these four related yet distinct diseases, two have been shown to impact humans—mad cow and CJD. The remaining two—CWD and scrapie—have yet to be linked to any human health concerns, let alone deaths. Scrapie has been around for at least 400 years and CWD for nearly 60 years, so that’s genuine reason for optimism.

To date, CWD has been confirmed in 33 states. Thankfully, Georgia is not one of the 33, although CWD has been confirmed in the Florida panhandle along the Alabama state line and in northwest Alabama near the Tennessee and Mississippi border. Like Georgia, South Carolina has never had a confirmed case of CWD in wild or captive deer. Georgia and South Carolina are the only two states in the Southeast without a known presence of CWD.

As for the recent report causing the uproar, extreme caution should be used when interpreting its conclusions. First, the “cluster” of reported infection consists of just two elderly men (one was 72 and the age of the other was not disclosed). Second, the study reported that the men consumed venison from a CWD-infected deer population. In other words, there was no evidence the men consumed infected venison, just venison from deer in an area with known CWD. Even if the men consumed CWD-infected venison, so too have tens thousands of elderly men over the past several decades. It’s worth noting here that CJD sporadically impacts roughly one in a million adults worldwide, primarily those 70 years of age or older. Therefore, sheer coincidence is just as likely, if not more so, the cause of disease in this case. Finally, while presented at a prestigious academic conference with a corresponding published abstract, this is not a peer-reviewed study. At this point, it’s simply an observation documented by researchers. In fact, the “study” was presented as a poster at the conference. Commonly, the weakest papers, or those in the preliminary stages of research, are relegated to poster status at academic conferences. About the only statement from their report that we agree with is that further investigation is needed. Until then, however, researchers and journalists alike should refrain from unsubstantiated CWD fear mongering.

Despite a continued lack of evidence that CWD can jump to humans, the possibility remains. Experimentally, it has been shown to be plausible in studies with genetically modified mice populations and at least one group of primates. More importantly, CWD is a contagious, always fatal disease of deer. Its cause—an abnormal, misshapen protein—can remain in the environment for decades, even in the complete absence of deer. At high enough levels of herd infection, CWD can limit a deer herd’s ability to maintain adequate reproduction and recruitment, limiting or preventing additional harvest by hunters. So, make no mistake, CWD is a bad deal for deer herds and deer hunters. But, at least for now, we can continue to remain cautiously optimistic that humans will not be harmed by consuming CWD-infected venison.