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Presence of BSE ("Mad Cow" disease) in U.S. uncertain Despite banning imports of Canadian beef on the basis of one infected cow, the United States can by no means be certain that it is free of BSE (bovine spongiform encephalopathy), the fatal prion disease that has of this writing killed 132 Europeans who ate the flesh of infected cows. It is likely that hundreds, perhaps thousands, of people ate flesh from the same and other infected animals indicating that the disease is not particularly contagious or that their immune systems were better able to resist the brain-destroying disease agent. It could be that an entire carcass is not infectious or that the disease is still incubating but has yet to reveal itself in more people. Also, some people are thought to be more genetically more susceptible to the disease. UPI Medical Correspondent, Steve Mitchell suggests (in an article published July 21, 2003) that "CJD (Creutzfeldt Jacob Disease, the human prion disease) screening may miss thousands of cases" and that some cases may have been misdiagnosed as AD (Alzheimer's Disease). CJD used to be separated into two types: the sporadic form that kills one in a million people and new variant CJD (vCJD) which can be traced to BSE. More recent research, however, has determined that BSE can cause both forms of the human disease. Mitchell quotes Laura Manuelidis, neuropathology section chief of surgery at Yale University who conducted the 1998 study that found that 13% of AD victims actually died from CJD: "Now people are beginning to realize that because something looks like (traditional sporadic) CJD, they can't necessarily conclude that it's not linked to (mad cow disease)." Both Britain and Switzerland have experienced an increase in CJD since their cows were found to be infected. Switzerland's incidence rose from between 8 and 11 new cases a year between 1997 and 2000 to 18 and 19 cases in 2001 and 2002 In the U.S., AD incidence has increased over 50 times from 857 deaths in 1979 to nearly 50,000 in 2000. According to Manuelidis, misdiagnosed CJD cases "could explain some of the increase we've seen." On the other hand, the increase could be due to the fact that people are living longer making them more likely to be afflicted with AD. In any case, the only sure way to diagnose these diseases, which have similar symptoms, is by autopsy after patients have died. ------------ "Something is out of balance, that the excessive unnaturalness we force on livestock could be catching up with us." - Philip Yam in The Pathological Protein: Mad Cow, Chronic Wasting, and Another Deadly Prion Diseases ----------- Even then, there is still room for controversy. Dr Peter Crinos and neuropathologist Nicholas Gonatas at the University of Pennsylvania Medical Center, suspicious because of the age of a 29-year-old CJD victim, performed an autopsy which revealed the microscopic holes found in the brains of vCJD victims. They sent three samples of the victim's brain tissue at two different times to the National Prion Disease Pathology Surveillance Center at Case Western Reserve University in Cleveland, but all results came back negative for vCJD. This may be an honest difference of opinion or an ineffective testing method, but government health officials have been reluctant to acknowledge indications that prion diseases are present in American animals and may be transmissible to humans. (CivAb Summer 1996). It would have been prudent to profit from the British experience by immediately banning all animal remnants from cattle feeds, but this was not done until later, presumably out of consideration for the profitability of livestock industry suppliers. There is substantiated evidence of prion disease in the U.S., the current spread of chronic wasting disease (CWD) in deer and elk for example. Three cases of CJD in young (under 30) people who had hunted or eaten venison were dismissed rather casually considering the circumstances. Squirrels in Kentucky are infected with an encephalopathy that has killed at least 11 people who ate their brains. More alarming was an outbreak in caged mink at a Wisconsin fur farm (CivAb Summer 1996). The mink had been fed almost exclusively on downed (unable to stand) cows. Because of the similarity in symptoms, there is a fair possibility that these cows may have been afflicted with a quieter strain of BSE, but tests have not confirmed this fear to date. Most of these cows are not autopsied as they are in Canada, however, and many are butchered for human consumption. More worrisome is the fact that 23 of the 2,614 American CJD victims were in their 20's and 30's, the younger age being a characteristic of vCJD. (CivAb Winter 1996-97). Studies conducted by University of Pennsylvania and Yale scientists found that respectively 6% and 14% of people who had officially died from AD had actually succumbed to CJD. (CivAb Spring 2001). In every case, except that of the Kentucky squirrels, the disease broke out in confined animals, possibly indicating that the prions are present but are not a major threat until animals are closely confined as they are under modern factory farm methods. In the last issue of CivAb, Michael Greger, MD, attributed the SARS outbreak to meat industry practices. Other zoonotic viruses such as influenza and Nipah originated from confined pigs and chickens. As Philip Yam wrote* "Something is out of balance, that the excessive unnaturalness we force on livestock could be catching up with us." *The Pathological Protein: Mad Cow, Chronic Wasting, and Other Deadly Prion Diseases |
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The Civil Abolitionist Autumn 2003 v.14 no. 2 |