"Mad Cow
Disease Spread More Extensive than U.S. Officials Realize."
By Michael Greger
In October 2001, 34-year-old Washington State
native Peter Putnam started losing his mind. One month he was
delivering a keynote business address, the next he couldn't form
a complete sentence. Once athletic, soon he couldn't walk. Then
he couldn't eat. After a brain biopsy showed it was Creutzfeldt-Jakob
disease, his doctor could no longer offer any hope. “Just take
him home and love him,” the doctor counseled his family. Peter's
tragic death, in October 2002, may have been caused by Mad Cow
disease.
Seven years earlier and 5000 miles away, Stephen
Churchill was the first in England to die. His first symptoms
of depression and dizziness gave way to a living nightmare of
terrifying hallucinations; he was dead in 12 months at age 19.
Next was Peter Hall, 20, who showed the first signs of depression
around Christmas, 1994. By the next Christmas, he couldn't walk,
talk, or do anything for himself. Then it was Anna's turn, then
Michelle's. Michelle Bowen, age 29, died in a coma three weeks
after giving birth to her son via emergency cesarean section.
Then it was Alison's turn. These were the first five named victims
of Britain's Mad Cow epidemic. They died from what the British
Secretary of Health called the worst form of death imaginable,
Creutzfeldt-Jakob disease, a relentlessly progressive and invariably
fatal human dementia. The announcement of their deaths, released
on March 20, 1996 (ironically, Meatout Day), reversed the British
government's decade-old stance that British beef was safe to eat.
It is now considered an “incontestable fact”
that these human deaths in Britain were caused by Bovine Spongiform
Encephalopathy (BSE), or Mad Cow disease. Bovine means “cow or
cattle,” spongiform means “sponge-like,” and encephalopathy means
“brain disease.” Mad Cow disease is caused by unconventional pathogens
called prions—literally infectious proteins—which, because of
their unique structure, are practically invulnerable, surviving
even incineration at temperatures hot enough to melt lead. The
leading theory as to how cows got Mad Cow disease in the first
place is by eating diseased sheep infected with a sheep spongiform
encephalopathy called scrapie.
In humans, prions can cause Creutzfeldt-Jakob
disease (CJD), a human spongiform encephalopathy whose clinical
picture can involve weekly deterioration into blindness and epilepsy
as one's brain becomes riddled with tiny holes.
We've known about Creutzfeldt-Jakob disease for
decades, since well before the first mad cow was discovered in
1985. Some cases of CJD seemed to run in families; other cases
seemed to just arise spontaneously in about one in a million people
every year, and were hence dubbed “sporadic.” The new form of
CJD caused by eating beef from cows infected with Mad Cow disease,
though, seemed to differ from the classic sporadic CJD.
The CJD caused by infected meat has tended to
strike younger people, has produced more psychotic symptoms, and
has often dragged on for a year or more. The most defining characteristic,
though, was found when their brains were sampled. The brain pathology
was vividly reminiscent of Kuru, a disease once found in a New
Guinea tribe of cannibals who ate the brains of their dead. Scientists
called this new form of the disease “variant” CJD.
Other than Charlene, a 24-year-old woman now
so tragically dying in Florida, who was probably infected in Britain,
there have been no reported cases of variant CJD in the U.S. Hundreds
of confirmed cases of the sporadic form of Creutzfeldt-Jakob disease,
however, arise in the United States every year, but the beef industry
is quick to point out these are cases of sporadic CJD, not the
new variant known to be caused by Mad Cow disease. Of course,
no one knows what causes sporadic CJD. New research, discussed
below, suggests that not hundreds but thousands of Americans die
of sporadic CJD every year, and that some of these CJD deaths
may be caused by eating infected meat after all.
Although the fact that Mad Cow disease causes
variant CJD had already been strongly established, researchers
at the University College of London nevertheless created transgenic
mice complete with “humanized” brains genetically engineered with
human genes to try to prove the link once and for all. When the
researchers injected one strain of the “humanized” mice with infected
cow brains, they came down with the same brain damage seen in
human variant CJD, as expected. But when they tried this in a
different strain of transgenic “humanized” mice, those mice got
sick too, but most got sick from what looked exactly like sporadic
CJD! The Mad Cow prions caused a disease that had a molecular
signature indistinguishable from sporadic CJD. To the extent that
animal experiments can simulate human results, their shocking
conclusion was that eating infected meat might be responsible
for some cases of sporadic CJD in addition to the expected variant
CJD. The researchers concluded that “it is therefore possible
that some patients with [what looks like]... sporadic CJD may
have a disease arising from BSE exposure.” Laura Manuelidis, section
chief of surgery in the neuropathology department at Yale University,
comments, “Now people are beginning to realize that because something
looks like sporadic CJD they can't necessarily conclude that it's
not linked to [Mad Cow disease]...”
This is not the first time meat was linked to
sporadic CJD. In 2001, a team of French researchers found, to
their complete surprise, a strain of scrapie—“mad sheep” disease—that
caused the same brain damage in mice as sporadic CJD.“This means
we cannot rule out that at least some sporadic CJD may be caused
by some strains of scrapie,” says team member Jean-Philippe Deslys
of the French Atomic Energy Commission's medical research laboratory.
Population studies had failed to show a link
between CJD and lamb chops, but this French research provided
an explanation why. There seem to be six types of sporadic CJD
and there are more than 20 strains of scrapie. If only some sheep
strains affect only some people, studies of entire populations
may not clearly show the relationship. Monkeys fed infected sheep
brains certainly come down with the disease. Hundreds of “mad
sheep” were found in the U.S. in 2003. Scrapie remains such a
problem in the United States that the USDA has issued a scrapie
“declaration of emergency.” Maybe some cases of sporadic CJD in
the U.S. are caused by sheep meat as well.
Pork is also a potential source of infection.
Cattle remains are still boiled down and legally fed to pigs (as
well as chickens) in this country. The FDA allows this exemption
because no “naturally occurring” porcine (pig) spongiform encephalopathy
has ever been found. But American farmers typically kill pigs
at just five months of age, long before the disease is expected
to show symptoms. And, because pigs are packed so tightly together,
it would be difficult to spot neurological conditions like spongiform
encephalopathies, whose most obvious symptoms are movement and
gait disturbances. We do know, however, that pigs are susceptible
to the disease—laboratory experiments show that pigs can indeed
be infected by Mad Cow brains—and hundreds of thousands of downer
pigs, too sick or crippled by injury to even walk, arrive at U.S.
slaughterhouses every year.
A number of epidemiological studies have suggested
a link between pork consumption and sporadic CJD. Analyzing peoples'
diet histories, the development of CJD was associated with eating
roast pork, ham, hot dogs, pork chops, smoked pork, and scrapple
(a kind of pork pudding made from various hog carcass scraps).
The researchers concluded, “The present study indicated that consumption
of pork as well as its processed products (e.g., ham, scrapple)
may be considered as risk factors in the development of Creutzfeldt-Jakob
disease.” Compared to people that didn't eat ham, for example,
those who included ham in their diet seemed ten times more likely
to develop CJD. In fact, the USDA may have actually recorded an
outbreak of “mad pig” disease in New York 25 years ago, but still
refuses to reopen the investigation despite petitions from the
Consumer's Union (the publishers of Consumer Reports magazine).
Sporadic CJD has also been associated with weekly
beef consumption, as well as the consumption of roast lamb, veal,
venison, brains in general, and, in North America, seafood. The
development of CJD has also, surprisingly, been significantly
linked to exposure to animal products in fertilizer, sport fishing
and deer hunting in the U.S., and frequent exposure to leather
products.
We do not know at this time whether chicken
meat poses a risk. There was a preliminary report of ostriches
allegedly fed risky feed in German zoos who seemed to come down
with a spongiform encephalopathy. Even if chickens and turkeys
themselves are not susceptible, though, they may become so-called
“silent carriers” of Mad Cow prions and pass them on to human
consumers. Dateline NBC quoted D. Carleton Gajdusek, the first
to be awarded a Nobel Prize in Medicine for his work on prion
diseases, as saying, “it's got to be in the pigs as well as the
cattle. It's got to be passing through the chickens.” Dr. Paul
Brown, medical director for the U.S. Public Health Service, believes
that pigs and poultry could indeed be harboring Mad Cow disease
and passing it on to humans, adding that pigs are especially sensitive
to the disease. “It's speculation,” he says, “but I am perfectly
serious.”
The recent exclusion of most cow brains, eyes,
spinal cords, and intestines from the human food supply may make
beef safer, but where are those tissues going? These potentially
infectious tissues continue to go into animal feed for chickens,
other poultry, pigs, and pets (as well as being rendered into
products like tallow for use in cosmetics, the safety of which
is currently under review). Until the federal government stops
the feeding of slaughterhouse waste, manure, and blood to all
farm animals, the safety of meat in America cannot be guaranteed.
The hundreds of American families stricken by
sporadic CJD every year have been told that it just occurs by
random chance. Professor Collinge, the head of the University
College of London lab, noted, “When you counsel those who have
the classical sporadic disease, you tell them that it arises spontaneously
out of the blue. I guess we can no longer say that.”
“We are not saying that all or even most cases
of sporadic CJD are as a result of BSE exposure,” Professor Collinge
continued, “but some more recent cases may be—the incidence of
sporadic CJD has shown an upward trend in the UK over the last
decade... serious consideration should be given to a proportion
of this rise being BSE-related. Switzerland, which has had a substantial
BSE epidemic, has noted a sharp recent increase in sporadic CJD.”
In the Nineties, Switzerland had the highest rate of Mad Cow disease
in continental Europe, and their rate of sporadic CJD doubled.
We don't know exactly what's happening to the
rate of CJD in this country, in part because CJD is not an officially
notifiable illness. Currently only a few states have such a requirement.
Because the Centers for Disease Control (CDC) does not actively
monitor the disease on a national level, a rise similar to the
one in Europe could be missed. In spite of this, a number of U.S.
CJD clusters have already been found. In the largest known U.S.
outbreak of sporadic cases to date, five times the expected rate
was found to be associated with cheese consumption in Pennsylvania's
Lehigh Valley. A striking increase in CJD over expected levels
was also reported in Florida and New York (Nassau County) with
anecdotal reports of clusters of deaths in Oregon and New Jersey.
Perhaps particularly worrisome is the seeming
increase in CJD deaths among young people in this country. In
the 18 years between 1979 and 1996, only a single case of sporadic
CJD was found in someone under 30; whereas between 1997 and 2001,
five people under 30 died of sporadic CJD. So five young Americans
died in five years, as opposed to one young case in the previous
18 years. The true prevalence of CJD among any age group in this
country remains a mystery, though, in part because it is so commonly
misdiagnosed.
The most frequent misdiagnosis of CJD among
the elderly is Alzheimer's disease. Neither CJD nor Alzheimer's
can be conclusively diagnosed without a brain biopsy, and the
symptoms and pathology of both diseases overlap. There can be
spongy changes in Alzheimer's, for example, and senile Alzheimer's
plaques in CJD. Stanley Prusiner, the scientist who won the Nobel
Prize for his discovery of prions, speculates that Alzheimer's
may even turn out to be a prion disease as well. In younger victims,
CJD is more often misdiagnosed as multiple sclerosis or as a severe
viral infection.
Over the last 20 years the rates of Alzheimer's
disease in the United States have skyrocketed. According to the
CDC, Alzheimer's disease is now the eighth leading cause of death
in the United States, afflicting an estimated 4 million Americans.
Twenty percent or more of people clinically diagnosed with Alzheimer's
disease, though, are found at autopsy not to have had Alzheimer's
at all. A number of autopsy studies have shown that a few percent
of Alzheimer's deaths may in fact be CJD. Given the new research
showing that infected beef may be responsible for some sporadic
CJD, thousands of Americans may already be dying because of Mad
Cow disease every year.
Nobel Laureate Gajdusek, for example, estimates
that 1% of people showing up in Alzheimer clinics actually have
CJD. At Yale, out of a series of 46 patients clinically diagnosed
with Alzheimer's, six were proven to have CJD at autopsy. In another
study of brain biopsies, out of a dozen patients diagnosed with
Alzheimer's according to established criteria, three of them were
actually dying from CJD. An informal survey of neuropathologists
registered a suspicion that CJD accounts for 2-12% of all dementias
in general. Two autopsy studies showed a CJD rate among dementia
deaths of about 3%. A third study, at the University of Pennsylvania,
showed that 5% of patients diagnosed with dementia had CJD. Although
only a few hundred cases of sporadic CJD are officially reported
in the U.S. annually, hundreds of thousands of Americans die with
dementia every year. Thousands of these deaths may actually be
from CJD caused by eating infected meat.
The incubation period for human spongiform encephalopathies
such as CJD can be decades. This means it can be years between
eating infected meat and getting diagnosed with the death sentence
of CJD. Although only about 150 people have so far been diagnosed
with variant CJD worldwide, it will be many years before the final
death toll is known. In the United States, an unknown number of
animals are infected with Mad Cow disease, causing an unknown
number of human deaths from CJD. The U.S. should immediately begin
testing all cows destined for human consumption, as is done in
Japan, should stop feeding slaughterhouse waste to all farm animals
(see http://organicconsumers.org/madcow/GregerBSE.cfm), and should
immediately enact an active national surveillance program for
CJD.
Five years ago this week, the Center for Food
Safety, the Humane Farming Association, the Center for Media &
Democracy, and ten families of CJD victims petitioned the FDA
and the CDC to immediately enact a national CJD monitoring system,
including the mandatory reporting of CJD in all 50 states. The
petition was denied. The CDC argued that their passive surveillance
system tracking death certificate diagnoses was adequate. Their
analysis of death certificates in three states and two cities,
for example, showed an overall stable and typical one in a million
CJD incidence rate from 1979 to 1993. But CJD is so often misdiagnosed,
and autopsies are so infrequently done, that this system may not
provide an accurate assessment.
In 1997, the CDC set up the National Prion Disease
Pathology Surveillance Center at Case Western Reserve University
to analyze brain tissue from CJD victims in the U.S. in hopes
of tracking any new developments. In Europe, surveillance centers
have been seeing most, if not all, cases of CJD. The U.S. center
sees less than half. “I'm very unhappy with the numbers,” laments
Pierluigi Gambetti, the director of the Center. “The British and
Germans politely smile when they see we examine 30% or 40% of
the cases,” he says. “They know unless you examine 80% or more,
you are not in touch.”“The chance of losing an important case
is high.”
One problem is that many doctors don't even
know the Center exists. And neither the CDC nor the Center are
evidently authorized to reach out to them directly to bolster
surveillance efforts, because it's currently up to each state
individually to determine how—or even whether—they will track
the disease. In Europe, in contrast, the national centers work
directly with each affected family and their physicians. In the
U.S., most CJD cases—even the confirmed ones—seem to just fall
through the cracks. In fact, based on the autopsy studies at Yale
and elsewhere, it seems most CJD cases in the U.S. aren't even
picked up in the first place.
Autopsy rates have dropped in the U.S. from 50%
in the Sixties to less than 10% at present. Although one reason
autopsies are rarely performed on atypical dementia cases is that
medical professionals are afraid of catching the disease, the
primary reason for the decline in autopsy rates in general appears
to be financial. There is currently no direct reimbursement to
doctors or hospitals for doing autopsies, which often forces the
family to absorb the cost of transporting the body to an autopsy
center and having the brain samples taken, a tab that can run
upwards of $1500.
Another problem is that the National Prion Disease
Pathology Surveillance Center itself remains underfunded. Paul
Brown, medical director for the National Institutes of Health,
has described the Center's budget as “pitiful,” complaining that
“there isn't any budget for CJD surveillance.” To adequately survey
America's 290 million residents, “you need a lot of money.” UK
CJD expert Robert Will explains, “There was a CJD meeting of families
in America in which...[the CDC] got attacked fairly vigorously
because there wasn't proper surveillance. You could only do proper
surveillance if you have adequate resources.”“I compare this to
the early days of AIDS,” says protein chemist Shu Chen, who directs
the Center's lab, “when no one wanted to deal with the crisis.”
Andrew Kimbrell, the director of the Center
for Food Safety, a D.C.-based public interest group, writes, “Given
what we know now, it is unconscionable that the CDC is not strictly
monitoring these diseases.” Given the presence of Mad Cow disease
in the U.S., we need to immediately enact uniform active CJD surveillance
on a national level, provide adequate funding not only for autopsies
but also for the shipment of bodies, and require mandatory reporting
of the disease in all 50 states. In Britain, even feline spongiform
encephalopathy, the cat version of Mad Cow disease, is an officially
notifiable illness. “No one has looked for CJD systematically
in the U.S.,” notes NIH medical director Paul Brown. “Ever.”
The animal agriculture industries continue to
risk public safety, and the government seems to protect the industries'
narrow business interests more than it protects its own citizens.
Internal USDA documents retrieved through the Freedom of Information
Act show that our government did indeed consider a number of precautionary
measures as far back as 1991 to protect the American public from
Mad Cow disease. According to one such document, however, the
USDA explained that the “disadvantage” of these measures was that
“the cost to the livestock and rendering industries would be substantial.”
Plant sources of protein for farm animals can
cost up to 30% more than cattle remains. The Cattlemen's Association
admitted a decade ago that animal agribusiness could indeed find
economically feasible alternatives to feeding slaughterhouse waste
to other animals, but that they did not want to set a precedent
of being ruled by “activists.”
Is it a coincidence that USDA Secretary Veneman
chose Dale Moore, former chief lobbyist for the National Cattlemen's
Beef Association, as her chief of staff? Or Alison Harrison, former
director of public relations for the Cattlemen's Association,
as her official spokeswoman? Or that one of the new Mad Cow committee
appointees is William Hueston, who was paid by the beef industry
to testify against Oprah Winfrey in hopes of convicting her of
beef “disparagement”? After a similar conflict of interest unfolded
in Britain, their entire Ministry of Agriculture was dissolved
and an independent Food Safety Agency was created, whose sole
responsibility is to protect the public's health. Until we learn
from Britain's lesson, and until the USDA stops treating this
as a PR problem to be managed instead of a serious global threat,
millions of Americans will remain at risk. |
