The Human Cost of Modern Farming
Antibiotics were developed to help keep us well, but their widespread use in modern agriculture may be putting our lives in jeopardy.
And the craziest food you ever ate?
When the question arrives, I begin with what you’d expect to hear from a food writer: chilied grasshoppers in Oaxaca, Mexico. Fried goat’s brain in Toronto. Tasmanian possum in Launceston, Australia (now, that was tough to swallow after watching the hairless creature get thrown around in a converted washing machine to tenderize it).
But the craziest food? Hands down, it was the chicken I ate one night in Tokyo. We had consumed nearly every part of the bird before the chef sent out glistening pink slices of raw chicken sashimi. To swallow the dish, I had to trust that it was free of the many pathogens that are routinely present on a chicken carcass in the supermarket.
Eating is an intimate act, and like most acts of intimacy, it requires you to trust your partner. Somebody-often a stranger-has created something that will end up inside you, part of you. This seems obvious in the face of a strange new food; less so when the most pervasive economic and social system on the planet requires us to place our faith in the people who produce what we eat daily, whether at a poncey restaurant in Tokyo or a KFC in Kingston, Ont.
The thing that scared me about eating raw chicken was the possibility that it contained bacteria that would make me sick. Salmonella, E. coli and campylobacter can kill us-or at least make us wish we were dead.
Not all microbes we host are dangerous. Hundreds of species have co-evolved to live peacefully with us, and to benefit us. This is also true of the animals in our lives, and bacteria move easily from one species to another. It follows that what happens on the farm can affect us at the dinner table. But most of us have no idea what actually goes on inside those unmarked chicken barns that sit just off the highway. It’s easier not to think about where our food comes from, or the risks it carries.
The notion that there is a connection between our health and that of other animals is not new. Sir William Osler, one of Canada’s most admired physicians and a father of modern medicine, is also considered a father of veterinary pathology. He believed that his students should study the anatomy and diseases of both human beings and animals. At the turn of the last century, in lecture halls where he taught at McGill in Montreal, veterinary students sat alongside medical students.
Today, each profession tends to collect and analyze its own data separately. We segregate these disciplines at our peril: many of the emerging infectious diseases that have plagued humans in recent decades-including Lyme disease, H1N1 and Ebola-began in animal populations and were transmitted to human beings, either directly or through our shared environment. “We are all swimming in the same pool,” says Jim Hutchinson, a Victoria-based expert in medical microbiology. But that pool has changed significantly in the last 60 years. Or, to be more precise, we changed it when we began killing off bacteria with antibiotics.
Nowhere is the division between human and veterinary medicine more significant than in the way we govern antibiotic use. Canada is one of the few developed countries that allows over-the-counter sales for animals (although two provinces require prescriptions). This makes it easy for farmers to obtain and abuse antibiotics; it also makes it difficult for scientists and regulators to track their use.
Farmers can bring in a three-month supply of unregistered, unregulated drugs from anywhere in the world, as long as they don’t sell them. According to Warren Skippon, who recently developed guidelines for the prudent use of antibiotics for the Canadian Veterinary Medical Association, we are the only industrialized country in the Western world that allows this. The upshot is that animals account for most of Canada’s antibiotic use: more than 1.6 million kilograms, according to a 2007 report from the Public Health Agency of Canada. By contrast, our doctors prescribe us 200,000 kilograms.
Antibiotics make modern farming possible. While the bulk of them are used in livestock, an editorial in The New England Journal of Medicine notes these drugs are also “dropped to salmon in cages in the seas and sprayed on fruit trees.” Even honeybees-which produce a sweetener with naturally antimicrobial properties-get treated with the stuff.
On February 6, the Canadian Federation of Agriculture celebrated Food Freedom Day-the day on which most Canadians will have earned enough at their jobs to pay for a year’s worth of groceries. This is nothing short of miraculous. Each decade seems to bring us cheaper, more plentiful plates of food, and there is no greater success story than chicken, the protein that ends up on our plates more than any other. About 2,700 Canadian farmers produced a staggering one billion kilograms of chicken in 2012. It looks like a good-news story-a chicken in every pot!-and in some ways it is.
In 1950, farmers spent 84 days raising their birds; today, most chickens are slaughtered after 38 days. Farmers can now produce a kilogram of meat using less than half the feed and in less than half the time. Such efficiencies help explain why the typical Canadian now eats 31 kilograms of chicken a year-21 kilograms more than we ate in 1965.
Antibiotics help broiler farmers maximize yield while minimizing cost. Pathogens flourish in a 10,000-square-foot barn housing 10,000 birds. Warm, littered and extremely crowded, a broiler barn is almost perfectly designed to promote the growth and transmission of germs. And, like toddlers in a daycare, the chickens pick up nearly every infection they’re exposed to.
Because of this, antibiotics are used not only as you or I use them, to control an infection that has already taken hold; farmers also administer them in low doses to try to prevent infection. In addition, they promote faster growth.
We don’t know why animals gain weight faster when they’re given low doses of antibiotics. One hypothesis is that the energy chickens might otherwise devote to fighting off (or perhaps just feeding) the gut’s microflora can instead be used to pack on pounds. It’s quite possible that something similar is happening in humans.
One of the top bacterial strains found in broiler chickens on the farm is Salmonella Heidelberg. Though it doesn’t affect chickens, it can cause severe illness in human beings-
extra-intestinal infection, septicemia, myocarditis. It can kill you. Bacteria such as S. Heidelberg are successful in part because they are very promiscuous. They can reproduce in minutes and refashion themselves with new bits of genetic code that make them more resilient than their predecessors.
A decade or so ago, the Public Health Agency of Canada’s Dr. Rebecca Irwin and her colleagues formed the Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) and collected isolates from both livestock and humans to monitor S. Heidelberg and other food-borne pathogens. Since they didn’t have access to farm samples, they collected bacteria from the animals’ intestines at abattoirs and shopped for meat at grocery stores.
They also reviewed information from a Université de Montréal survey of Quebec hatcheries that were using the antibiotic ceftiofur to control E. coli infections. Ceftiofur also belongs to a World Health Organization class of “medically important” drugs. Doctors use ceftriaxone, a related drug for humans, to treat patients with a range of serious bacterial infections, including those caused by bugs like S. Heidelberg. Scientists were surprised to find a direct correlation between the ceftiofur injected into the eggs and resistance to ceftriaxone in S. Heidelberg. Moreover, the hard-to-treat bug was turning up on chicken in stores-and in patients in hospitals, first in Quebec and then in Ontario.
It wasn’t the first scientific inquiry to show that using antibiotics on farm animals could elevate resistance levels in food-borne pathogens. In 1975, Stuart Levy, an American microbiologist, established a family farm outside Boston and introduced two groups of chickens. One group received low doses of antibiotic-laced feed; the other did not.
In 2010, Levy appeared before the United States House Committee on Energy and Commerce to argue for the prudent use of antibiotics. “Within 24 to 48 hours, the chickens given the oxytetracycline-laced feed began to excrete tetracycline-resistant E. coli,” he recalled. After three months, the chickens were excreting E. coli that was also resistant to many other drugs. Levy published his findings in The New England Journal of Medicine and in Nature.
Each time we use antibiotics, we increase the odds for resistance to them. Any bacterium able to survive our antibiotic onslaught will reproduce resistant copies of itself. Once resistant bacteria are established, they can move from animal to animal-humans included-without the aid of any additional antibiotics. Create resilient “superbugs” that live on chickens, and they can travel easily through the food chain: from the farm to the abattoir to the supermarket to the dinner plate.
Each year, roughly one in eight Canadians-four million people-get sick from food-borne illnesses. Some of those illnesses involve resistant pathogens, which lengthen hospital stays, complicate treatments and at least double their cost.
But there’s a bigger problem, says Jim Hutchinson, who now heads up an antimicrobial stewardship program on Vancouver Island. Antibiotics, he says, have done more to extend our life expectancy than any other drug we use to treat disease: pneumonia, skin infections and even urinary tract infections can be fatal without them. Antibiotics make modern medicine possible.
Medical professionals around the world warn of a post-antibiotic era, when bacteria will be resistant to all the drugs we can throw at them. The prospect is scary enough to be called a “crisis” (by the WHO), a “nightmare” (by the CDC) and a “catastrophic threat” (by UK chief medical officer Sally Davies). If antibiotics no longer work, our lives end much sooner.
Some scientists compare antimicrobial resistance to climate change: it’s caused by human activity and we’ve known about it for a long time, but the problem is so complex, and involves so many players in so many places, that a solution seems beyond reach.
The role that agriculture plays in antimicrobial resistance in humans has long been the subject of acrimonious debate. In this way, too, the issue resembles climate change: it’s easier to point fingers than to fix the problem. Doctors write scathing commentary in The New England Journal of Medicine laying blame at the feet of farmers. In response, farmers point to the studies that suggest overuse of antibiotics in human medicine is the worse offender.
Many doctors, including Hutchinson, agree with the farmers. There is great concern that many countries don’t even regulate over-the-counter sales of human medications. Still, no one denies that agricultural antibiotics contribute to resistance and that reforms to the way we distribute drugs in Canada are long overdue. Ignoring the use of antibiotics in one part of the food chain, or one part of the world, imperils us all.
In the fall of 2014, I visit Derek Detzler, a modern-day chicken farmer in southwestern Ontario. For more than a decade, he has been grappling with how to control infection in broiler flocks without resorting to drugs. “Nothing works as well as a working antibiotic,” he says.
In the early aughts, across the industry, chickens were becoming less healthy, growing more slowly and requiring more feed to gain any weight. And, in a mirror of what was happening in our hospitals, the antibiotics used to fight disease didn’t seem to be working as well as they once did. At the time, Detzler worked in research and development at a feed mill. His boss, afraid of losing his competitive edge, charged him with finding an alternative. What Detzler learned, through trial and error, informed his own flock management when he took over his dad’s 324-hectare operation six years ago.
The farm is a 10-minute drive from Walkerton, the town that made national headlines in 2000 when agricultural runoff contaminated the water supply with E. coli and infected half of its 5,000 residents. It’s the town where Detzler and his family went in 2000 for a Mother’s Day brunch. Everyone ordered a pop except Detzler’s four-year-old daughter, Madison, who drank the water and ended up in the intensive care unit in nearby London with kidney failure.
Even before this, Detzler had taken an interest in animal health; when he was younger, he wanted to go to vet school. It’s taken about five years, he says, to figure out how to control infections without antibiotics. He’s still learning. Sitting at a polished granite island in his shiny stainless-steel kitchen, Detzler explains that he manages coccidiosis, an intestinal infection that is nearly ubiquitous in modern coops, by vaccinating the chickens with a pre-resistant strain of the bacteria to provide some immunity and make sure that the barn is dominated by vulnerable coccidiosis variants.
It has taken him a long time to figure this out. “It hurt a lot,” he says of the early days of experimentation. “Mortality would skyrocket.” His mortality rates are still a bit higher than those of conventional farmers (he would not be specific), and his chickens take a few more days to reach slaughter weight. But he can charge a premium for them, since they get sold as antibiotic-free.
A lot of the work Detzler does off the farm these days involves advising and troubleshooting with other producers who want to reduce or eliminate the use of drugs. “You have to love to do it,” he says, “because it’s harder.” But it will take more than love to change a $2.3-billion industry’s business model.
Countries such as Denmark and the Netherlands have already taken action. Following bans in both nations on the non-therapeutic use of antibiotics in livestock, resistance to some drugs dropped by half. Meanwhile, production costs and supermarket prices have done what many thought impossible: they have remained stable.
Discussions about the prudent use of antibiotics often promote the principle of stewardship. Levy calls them “societal drugs” because their use by one individual affects us all. We could also think of them as a common resource, like water, that must be protected. “Use is a privilege, not a right,” says Skippon, “whether we’re talking about a livestock producer or the parent of a small child with an ear infection.”
A few years ago, Ontario’s University of Guelph researcher John Prescott appeared before a parliamentary committee in Ottawa to talk about regulating antibiotics and the 38 recommendations made in a landmark report to Health Canada in 2002. “Most of these recommendations have not been acted upon,” he said. “Currently, I think nobody in the federal government is in charge-just the resistant bacteria.”
Bacteria, like us, are just trying to survive. They predate us by millions of years and will probably outlast us by millions more. But they are even less visible than the chickens our farmers raise behind locked doors, which means they are even easier to forget. During our interview, Prescott allows himself a moment of pessimism: he worries aloud that it’s all too little too late and that rumours of regulatory change would never translate into concrete action. Then he quickly recovers.
“Bacteria can change,” he says. “But so can we.”
© 2014 by Sasha Chapman. The Walrus (January/February 2015). thewalrus.ca