It Can Happen Here.

Savage Outbreaks of Animal-Borne Diseases Raise Fears that the Next Epidemic Could be in the U.S.

As infections go, mad cow disease and foot-and-mouth disease don't have much in common. Mad cow disease is hard to transmit, takes years to incubate in an infected animal and is almost impossible to detect until symptoms emerge late in the course of the infection. Foot-and-mouth, by comparison, is one of the most contagious animal diseases known. Unlike mad cow disease, which is hard to spread but always fatal, foot-and-mouth disease spreads quickly but rarely even kills animals and is considered harmless to human beings.

The fact that both diseases have emerged in the United Kingdom is mostly a matter of British bad luck. But both have something to teach us about the virtues of precaution. Diseases of livestock and people lurk in hidden crevices of the world, and the very technologies that we celebrate as emblems of modern progress can also serve as vehicles for transforming those diseases into epidemics. Just as AIDS spread throughout the world thanks in part to the speed and ease of modern travel, other diseases are cropping up with increasing frequency as a result of factors including increasing urbanization of wildlife habitats and intensive livestock farming practices.

Origins of an Epidemic

The recent British outbreak of foot-and-mouth disease began in early February on a farm in Northumberland, England's most northerly county. By February 25, most of the country had been declared a contaminated area. Its spread was assisted on February 13 when 40 sheep were purchased in Northumberland and shipped to Devon, a county on England's southwest peninsula. By the time the outbreak was identified as foot-and-mouth disease, consignments of sheep and pigs had already been shipped from infected areas throughout the country and to other parts of Europe. By March 1, the number of detected cases had reached 30, with new outbreaks occurring in Ireland and Scotland. Europe started slaughtering animals imported from Britain as soon as the epidemic became apparent, but by then, antibodies to foot-and-mouth were already being found in Germany. By March 21, nearly 400 cases had been detected, and the army had been called in to help with the disposal of carcasses as thousands of animals were slaughtered in an effort to eradicate the disease.

Europe will spend billions of dollars bringing this particular outbreak under control. But outbreaks of foot-and-mouth have risen throughout the world, due to activities that spread the disease, such as illegal smuggling of animals, international tourism and the globalization of trade. "The last two years have been among the worst on record, with more than 60 countries experiencing outbreaks, including many which have not had one in generations," reports the Guardian of London. Examples include Taiwan, Korea, Brazil and South Africa, as well as an outbreak last year in Japan that was traced back to diseased straw imported from China via Russia.

Unlike foot-and-mouth disease, which has vexed farmers for centuries, mad cow disease is a recent phenomenon created by technical innovations in agricultural production itself. The innovation that caused it was actually quite simple. In order to dispose of slaughtered animal parts that have no commercial value, the meat industry put them through a "rendering" process that consisted of grinding them up and cooking them in large vats to produce a product called "meat and bone meal" that was then fed back to other animals. This created what was essentially a cannibalistic feeding loop, as cows consumed the remains of other cows, sheep were fed to sheep, pigs to pigs, chickens to chickens and so forth.

Common sense might dictate that this practice is a bad idea, but the scientists and farmers who used this material genuinely believed it would be safe. What they didn't realize was that this feeding loop was also an amplification loop through which mad cow disease--something that had never even been detected prior to the 1980s--would become a devastating epidemic that has so far killed more than 170,000 cattle and began to kill human beings in 1996. To date, nearly 100 people have died, presumably from eating infected beef, and scientific projections for the eventual death toll in Europe range from a few hundred to 100,000.

Renderers like to point out that they deserve credit for helping to dispose of large quantities of animal waste that would otherwise putrefy and create a massive disposal problem. But modern large-scale agribusiness has created a problem that it only partially manages to solve. Even today, notwithstanding the nightmare that mad cow disease has meant for Europe, the U.S. meat industry and regulatory agencies have failed to take all the precautions needed to protect animal and human health. Europe has adopted tough regulations that ban the use of animal meat and blood in livestock feed.

Inadequate Protection

The U.S. has adopted regulations too, but with glaring holes. In March, the U.S. Department of Agriculture (USDA) confiscated two flocks of sheep imported from Europe, which they believe may have been exposed to mad cow disease. Unfortunately, U.S. agencies continue to rely heavily on attempts to interdict foreign imports that may carry the disease, while winking and nodding at practices that could cause equally devastating homegrown equivalents to emerge. It is still legal in the U.S., for example, to feed rendered cows to pigs, whose remains are fed in turn back to cows. And it is still perfectly legal to use cow blood in cattle/bed, a practice banned in Europe. The regulations that do exist are limply enforced. Bovine meat and bone meal is supposed to be labeled, "Do not feed to cows," but a Food and Drug Administration (FDA) investigation found that hundreds of feed makers are violating the law.

Modern feedlot farming, which force-feeds animals "scientifically blended rations" designed to maximize growth and minimize costs, has also introduced a variety of other practices that threaten to spread diseases. In addition to the rendered remains of their cousins, livestock today consume a variety of substances that are quite different from the grass and hay on which they conventionally have been nurtured, including industrial wastes, such as sawdust, wood chips, twigs, ground-up newspapers, cement dust from kilns and even treated manure and sewage sludge from municipal composting plants. This may not make particularly appetizing reading as you are about to sit down to dinner, but from industry's perspective, there is no harm in it. These materials help cut down on costs, dispose of wastes and translate into benefits for the consumer in the form of lower prices for your Chicken McNuggets.

As far as industry is concerned, there is no proof that these practices are dangerous, so why should they hesitate? But scientific research is still lacking in regards to the risks associated with these practices. No one knows how the recent outbreak of foot-and-mouth disease arrived in England, but it got there anyway. No one knew in advance that feeding livestock rendered meat and bone meal would cause an epidemic of mad cow disease, but it did. And no one knows today whether the introduction of genetically modified organisms into our food supply will create previously unknown allergies or other health problems in the people who consume them.

An International Problem

What we do know is that illnesses stemming from modern agriculture seem to be a growing problem worldwide. In October of last year, the United Nations Food and Agriculture Organization warned that increasing movements of people, animals and animal products for trade are leading to a greater spread of animal diseases across national borders. It noted that a number of livestock diseases have been diagnosed for the first time outside their "normal" areas of origin--sometimes thousands of miles away. In Yemen, close to the Saudia Arabian border, some 100 people have died from the first known outbreak of Rift Valley fever outside Africa. Outbreaks of bluetongue disease, a viral disease of sheep, have been reported in Bulgaria and Sardinia, locations where the disease was previously unknown. In addition to mad cow disease and foot-and-mouth disease, the United Kingdom saw an outbreak of classical swine fever, a disease believed to have been eradicated in the UK many years ago. The recent infection is thought to have been introduced through imported meat products.

Foodborne diseases among people also appear to be rising. In 1990, the Food and Nutrition Board of the National Academy of Sciences attributed the increase to "automated food processing, increased reliance on fast foods, greater use of prepackaged foods and microwave ovens, urbanization, public naivete about food production and slaughter methods and lack of knowledge about the hygienic precautions required at all stages of food handling." The foodborne nature of many illnesses often goes unrecognized by the victims, but government agencies have estimated that as many as 81 million cases of foodborne illness occur in this country each year, accounting for approximately 9,000 deaths.

The most common killers are not exotic diseases like mad cow disease, which the USDA has yet to detect in the U.S. They include E. coli O157:H7, Salmonella typhimurium and Listeria monocytogenes--bacteria that have become ubiquitous in the human food supply. Severe forms of E. coli food poisoning, often originating from fast food, kill 500 people a year.

Salmonella, which causes an intense flu-like illness that can be fatal, has been linked to the consumption of eggs, poultry, milk and dairy products and a variety of other foods. The FDA's Center for Food Safety and Applied Nutrition estimates that two to four million cases of salmonellosis occur every year in the U.S. The Center says, "[Salmonella] isolations from humans have shown a dramatic rise in the past decade, particularly in the northeast United States (six-fold or more)."

Listeria, which can cause fatal blood poisoning, miscarriages in pregnant women and meningitis, is believed to spread through ready-to-eat foods such as hot dogs, luncheon meats or cold cuts. According to the Centers for Disease Control and Prevention, some 2,000 people in the U.S. come down with serious cases of listeriosis each year, which is responsible for approximately 500 deaths.

The benefits of modern agricultural innovation are evident. The cost, however, is that we are performing a massive global experiment with ourselves and our children as the test subjects. CONTACT: Center for Media & Democracy, [phone], www.prwatch.org; Food and Nutrition Board, Institute of Medicine, www.nationalacademies.org; Food & Water, www.foodandwater.org; USDA Food and Nutrition Information Center, www.nal.usda.gov/fnic.

British Cases of Conventional and Variant
Creutzfeldt-Jakob Disease (vCJD)

                        Reported as of March 2, 2001

Year        Sporadic   Other   vCJD probable   vCJD confirmed   Total

1985           26        2          0                0            28
1986           26        0          0                0            26
1987           23        1          0                0            24
1988           22        2          0                0            24
1989           28        4          0                0            32
1990           28        5          0                0            33
1991           32        4          0                0            36
1992           44        8          0                0            52
1993           38        8          0                0            46
1994           51        8          0                0            59
1995           35        9          0                3            47
1996           40       10          0               10            60
1997           59       11          0               10            80
1998           63        8          0               18            89
1999           61        8          0               15            84
2000           42        3          1               27            73
2001(YTD)       3        0          9                2            14

"Sporadic" CJD refers to cases where the cause is unknown. "Other"
refers to cases with known causes other than exposure to mad cow
disease. This includes CJD, which has been caused accidentally by
medical procedures, as well as Fatal Familial Insomnia (FFI) and
Gerstmann-Straussler-Scheinker Syndrome (GSS), rare forms of human
transmissible spongiform encephalopathy known to be caused by
genetic mutations of the prion protein. The term "vCJD" refers to
variant Creutzfeld-Jakob Disease (sometimes also called "new variant
CJD" or "nvCJD"), a form of the disease that scientists have shown
is caused by exposure to mad cow disease. Cases listed as "vCJD
probable" have not yet been confirmed because the victim is either
still alive or is awaiting post-mortem results. Source: British
Department of Health, Monthly Creutzfeldt-Jakob Disease Statistics,
March 5, 2001 (http://213.38.88.195/coi/coipress.nsf).

RELATED ARTICLE: What About Mad Deer Disease?

Although the USDA is quick to proclaim that mad cow disease has never been detected in the United States, it is less eager to talk about a similar disease that is occurring here--chronic wasting disease (CWD), a transmissible spongiform encephalopathy that is similar to mad cow disease except that it occurs in deer and elk instead of cattle.

CWD was first discovered in the 1960s and has since been spreading slowly through the deer and elk population, mostly in a few western states such as Colorado and Wyoming. A few cases have also been detected in Canada. Mike Miller of the Colorado Division of Wildlife describes CWD as "an epidemic occurring in slow motion."

In recent years, two hunters and a woman who regularly ate venison have died from Creutzfeldt-Jakob Disease (CJD) in the United States. Dr. Ermias Belay of the U.S. Centers for Disease Control and Prevention has studied the circumstances related to the three deaths. They've raised concern, he notes, primarily because of the unusually young age of those infected. Like mad cow disease and CWD, CJD is a transmissible spongiform encephalopathy that kills its victims by filling their brains with microscopic sponge-like holes. It occurs throughout the world but is quite rare, accounting for an estimated one death per million people per year. Moreover, CJD almost always occurs in people older than age 45, yet all three of the venison-eating victims in the United States contracted their disease before the age of 30.

In a January presentation to the Food and Drug Administration, Belay noted that the unusually young age of the victims, combined with the fact that they all ate venison, suggested "a possible relationship with CJD." His review of the evidence found no common genetic or clinical signs that would point to CWD as the cause, and therefore he concluded that there was "no strong evidence of a causal link." However, absence of proof is not proof of absence. He added, "Our conclusions are limited to three patients, and continued surveillance remains very critical to continue to monitor the possible transmission of chronic wasting disease to humans."

The three victims' brains were autopsied by Dr. Pierluigi Gambetti, professor of pathology and director of the National Prion Disease Pathology Surveillance Center at Case Western University in Cleveland, Ohio. Like Belay, Gambetti did not find proof that the hunters died from exposure to CWD, but he did not find anything to disprove it either.

Gambetti says that he personally will avoid eating venison. "Why should I? I can eat something else," he says. "But that's not because I really think there is great danger. I just think the whole issue of prion disease in the United States, both in animals and humans, has to be confronted seriously. We really have to do more." Gambetti is hesitant to say there is danger of an epidemic, but he agrees that more research is needed.

"The deer issue is potentially a problem," CJD expert Paul Brown of the National Institutes of Health said recently at a meeting of CJD Voice, a support group for family members of CJD victims. "I don't think it's a problem yet, but I think it could possibly explode," Brown said. "What we're seeing in this country is a handful of cases that has excited the popular imagination because of the possible association with deer and venison and elk [and] the geographical association. A cause-and-effect might be established, in which case it will be very important. Or it might be a chance cluster of a few young people due to random clumping alone, and when we look at it in five years, we may not see any more."

But while scientists continue to study the question, without any clear evidence one way or the other, hunters in the U.S. continue to eat venison from animals with a disease that definitely kills the animals themselves and may turn out to kill human beings.--S.R.

RELATED ARTICLE: Mad Cow Disease: The Death Toll Rises

In 1995, Stephen Churchill, the 19-year-old son of a fire inspector, became the first Briton to die of variant Creutzfeldt-Jakob Disease (vCJD, the form of CJD that has been linked to mad cow disease). The first signs were a gradual deterioration of Churchill's college grades, accompanied by depression and dizziness, followed by a loss of coordination and balance. "About four months before he died, he started to stagger," says his mother, Dorothy Churchill. "It brought back memories of seeing the cows we had seen on the news. I mentioned it to somebody, and then I dismissed it because it seemed a ridiculous idea."

Stephen Churchill had visited his aunt's farm every year for eight years, coming into contact with cows and drinking unpasteurized milk. Only a few months after Churchill died, 29-year-old Michelle Bowen, who had worked at a butcher's shop when she was a teenager, also died from vCJD.

In the five years since the British government concluded that people were dying from exposure to mad cow disease, fewer than 100 people have died from vCJD. This statistic may not seem terribly alarming, but public health officials familiar with the long incubation period of this class of diseases are far from complacent. According to an analysis published in the January-February 2001 issue of the Centers for Disease Control and Prevention's Emerging Infectious Diseases, which was written by leading researchers from both the United Kingdom and the U.S., the death toll may eventually surpass 100,000.

"Much of the lingering uncertainty about the extent of the vCJD outbreak is attributable to the fact that the incubation period of vCJD is unknown," say the researchers, who include Paul Brown of the U.S. National Institutes of Health, Robert Will of England's National Creutzfeldt-Jakob Disease Surveillance Unit and Linda Detwiler of the USDA. "If the average incubation period is 10 to 15 years," they say, "the earliest patients with vCJD would have been infected in the early 1980s, when BSE [Bovine Spongiform Encephalopathy] was still silently incubating in small but increasing numbers of cattle. If, however, the average incubation period of vCJD is five to 10 years, the earliest human infections would have begun in the mid- to late 1980s, when exposure to BSE was maximal. Depending on assumptions about the incubation period and other variables, the total extent of the outbreak could range from fewer than one hundred to hundreds of thousands of cases."

This broad range of uncertainty has actually narrowed since 1996, when scientists first discovered that mad cow disease had jumped species and was beginning to kill people. Back then, scientists estimated that the eventual human death toll would be somewhere between a few dozen and a few million. By tracking the rate of increase of the epidemic over the course of the past five years, they have been able to narrow the range significantly, but it will still be several years before anyone has an accurate estimate of the number of people infected. --S.R.

SHELDON RAMPTON edits PR Watch and is the co-author, with John Stauber, of books including Mad Cow USA: Could the Nightmare Happen Here? and Trust Us, We're Experts: How Industry Manipulates Science and Gambles With Your Future.