Having spent many years living and travelling in Europe, and having worked in both the growth hormone and blood products industry, I’ve probably had more than my fair share of potential exposure to prions. I’ve certainly attended enough scientific meetings, written enough position papers and sat through way too many chilling and tragic BBC news broadcasts on the subject. Here in the US, however, the subject has generated relatively little media or clinical attention. So I was interested to hear that the Centers for Disease Control and Prevention (CDC) has just published the results of its investigation into the risk of human exposure to prion disease. Specifically they looked at the risks associated with:
- venison consumption
- travel to areas in which prion diseases have been reported
Although rare, human prion diseases such as vCJD, result in the brain developing sponge-like holes. This causes progressive memory and personality changes, dementia, and problems with eyesight, speech and movement. CDC investigators evaluated the results of a 2006-2007 survey conducted in Connecticut, Georgia, Maryland, Minnesota, New Mexico, Oregon, and Tennessee, as well as five counties in the San Francisco Bay area, seven counties in the Greater Denver area, and 34 counties in western and northeastern New York. Survey participants were asked about behaviors that could be associated with exposure to the agents causing BSE and CWD, including travel to the nine countries considered to be BSE-endemic:
- United Kingdom
- Republic of Ireland
- The Netherlands
…and their cumulative length of stay in each of those countries. 29.5% of survey respondents reported travel to at least one of the nine BSE endemic countries since 1980. Travel to the UK was reported by 19.4%, and the median duration of travel was 14 days.
Respondents were asked if they ever had hunted for deer or elk, and if that hunting had taken place in northeastern Colorado, southeastern Wyoming or southwestern Nebraska, areas considered to be CWD-endemic. They were also asked if they had ever consumed venison, the frequency of consumption, and whether the meat came from the wild. 18.5% of survey respondents reporting having hunted for deer or elk. Of these, 1.2% reported having hunted for deer or elk in CWD-endemic areas. Venison consumption was reported by 67.4% of respondents with 88.6% of those having obtained all of their meat from the wild.
The CDC advises hunters in CWD-endemic areas to take simple precautions such as avoiding consuming meat from sickly deer or elk, avoiding consuming brain or spinal cord tissues, minimizing the handling of brain and spinal cord tissues, and wearing gloves when field-dressing carcasses.
And while the Agency did not warn against travel to Europe they say that the prevalence and extent of travel to the UK indicate that prion health concerns may also become issues for US residents. “While prion diseases are rare, they are generally fatal for anyone who becomes infected. More than anything else, the results of this study support the need for continued surveillance of prion diseases,” commented lead investigator Joseph Y. Abrams, MPH, National Center for Emerging and Zoonotic Infectious Diseases.