Recently, it looked like antibiotic use in agriculture in the United States was trending down–the result of decades of pressure by consumers on companies such as McDonald’s and Perdue Farms. But a new analysis by academics who study antibiotic use predicts that the drugs may not actually be going away. They might just be relocating.
In a paper published in the Proceedings of the National Academy of Sciences, Ramanan Laxminarayan of the Center for Disease Dynamics, Economics and Policy (CDDEP) in Washington, D.C. and colleagues predict that global use of agricultural antibiotics will rise by two-thirds by the year 2030—and that use in emerging economies such as China and India will double.
The authors, who hail from eight different institutions, say the increases will be driven by rising demand for meat among newly affluent middle classes. Two-thirds of the increase in drug use will be driven by countries simply raising more animals, and the rest will be due to those countries’ shifting to intensive livestock raising. (That’s when animals are given antibiotics to make them gain weight and to protect them from diseases that spread in close confinement.)
The animals most likely to get the drugs, they predict, will be pigs, and after them, chickens. (As the nonprofit Worldwatch Institute has shown, pork is the most widely consumed met in the world, though chicken consumption is growing the fastest.)
By 2030, the researchers say, the biggest users of farm antibiotics will be China (which will be using 30 percent of the world’s total), the United States (10 percent of the total; we use 13 percent now), Brazil (8 percent), India (4 percent), and Mexico (2 percent).
The countries where antibiotic consumption will grow the most are ones whose economies are expanding but still rank behind China and India: Myanmar (where farm antibiotic use is projected to rise by 205 percent), Indonesia (202 percent), Nigeria (163 percent), Peru (160 percent), and Vietnam (157 percent). In 2030, the authors predict that the use of antibiotics on farms just in Asia will equal 82 percent of the world’s entire consumption today.
The paper says:
In low- and middle-income countries, rising incomes have driven an unprecedented growth in demand for animal protein… In Asia, daily animal protein intake grew from 7 grams per capita per day to 25 grams per capita per day between 1960 and 2013 while the proportion of the diet coming from rice and wheat progressively decreased, primarily among higher-income adults. To meet this demand, countries such as Brazil, Russia, India, China, and South Africa have shifted toward highly cost-efficient and vertically integrated intensive livestock production systems. Because these production systems necessitate antimicrobials to keep animals healthy and maintain productivity, rising incomes in transitioning countries are effectively driving an increase in antimicrobial consumption and thereby antimicrobial resistance.
As numerous studies have documented, farm antibiotic use creates resistant bacteria in the animals receiving them; those bacteria leave farms in water or dust or on the animals themselves, and reach consumers either on meat, or indirectly by spreading in the environment.
“Antibiotic resistance is a dangerous and growing global public health threat that isn’t showing any signs of slowing down,” Laxminarayan, who is CDDEP’s director and a senior research scholar at the Princeton Environmental Institute, said in a statement. “Our findings advance our understanding of the consequences of the rampant growth of livestock antibiotic use and its effects on human health—a crucial step towards addressing the problem of resistance.”
To achieve the predictions, the researchers used data on farm sizes and drug-use trends from industrialized countries—the only ones for which such data is routinely collected and reliable—applied them to stats about agriculture and population in developing nations and then projected them forward. They assumed that intensive agriculture looks similar the world over—but added that, because most Western nations now place some restrictions on agricultural antibiotic use, the data on which they based their assumptions might be artificially low. That is, consumption in 2030 might be even higher than they’re predicting. (See our story here on how the Dutch have phased out farm antibiotics.)
Without similar control programs in the developing world, antibiotic use and antibiotic resistance will burgeon, Laxminarayan warned: “The invention of antibiotics was a major public health revolution of the 20th century.Their effectiveness—and the lives of millions of people around the world—are now in danger.”