The widespread use of antifungals in food production is hastening an increase in drug-resistant infections, putting millions of people at risk.
On the surface, our modern system of food production looks efficient: It produces plenty of food and seems highly innovative. But it also encourages people to eat unhealthy sugars and fats, while fully one-third of all food produced is lost or goes to waste. Industrial agriculture is defiling lakes and rivers with chemical runoff and depleting irreplaceable fertile topsoils.
The food and agriculture industries are pretty good at keeping these and other costs hidden from public view. But that may get harder if people start dying in large numbers, which isn’t far-fetched, according to the United Nations. Health officials around the world are struggling with the explosive rise of deadly drug-resistant strains of the fungus Candida auris, which prey on people with weakened immune systems. Worryingly, their emergence may be tied to indiscriminate use of fungicides in agriculture and food production.
First detected in Japan in 2009, C. auris — a pathogen that is mostly associated with health-care environments and can be spread through contact with infected patients — has since spread across the globe, alarming public health authorities. It’s extremely hard to detect and eradicate, and it kills more than 50 percent of those it infects. In the U.S., hundreds of new infections have been reported in the past few years, mainly in New York, Illinois and New Jersey. The Centers for Disease Control and Prevention are trying to educate physicians about best practices.
Just as important as education is determining the origin of these strains, some of which are resistant to all three major classes of antifungal medicines. The resistant strains, genetic studies indicate, have arisen independently on multiple occasions and been found in patients having had no prior treatment with medical fungicides. So where did they come from?
One possibility looms large: that the new strains have emerged due to fungicide use not in medicine, but in agriculture. Fungicides known as azoles are widely used to deter fungal growth in plants and fruits. They account for about one-third of all global fungicide sales and, remarkably, are chemically almost identical to the antifungal agents doctors rely on to treat humans.
Research has already implicated agricultural fungicides in the emergence of another drug-resistant fungus, Aspergillus fumigatus. While the fungus doesn’t attack crops, it can be found in soils all over the world; it is one of the most common mold infections worldwide, and it is potentially lethal to those with weakened immune systems. Drug-resistant strains found in fungicide-treated fields or flower beds show specific genetic mutations just like those in Aspergillus detected in infected patients
It will take further research to determine if the new strains of C. auris have their origins in agriculture, but Aspergillus has already illustrated the perils of modern farming. Antibiotics are applied on a massive scale in food production, pushing the rise of bacterial drug resistance. A British government study published in 2016 estimated that, within 30 years, drug-resistant infections will be a bigger killer than cancer, with some 10 million people dying from infections every year.
We don’t have to end up there. Pesticide use on most farms can be greatly reduced, or even eliminated, without reducing crop yields or profitability. Methods of organic farming, even as simple as crop rotation, tend to promote the growth of mutualistic fungi that crowd out pathogenic strains such as C. auris. Unfortunately, because conventional agriculture is heavily subsidized and market prices don’t reflect the costs to the environment or human health, organic food is more expensive and faces an uphill battle for greater consumption.
Of course, improved technology could help, with drugs of new kinds or in breeding and engineering resistant strains of plants. There’s also plenty of opportunity for lightweight agricultural robots, which can weed mechanically or spray pesticides more accurately, reducing the quantity of chemicals used. But tech shouldn’t be the sole focus just because it happens to be the most profitable route for big industries.
In his recent book “The Grand Food Bargain,” agricultural expert Kevin Walker of Michigan State University traces the history of farming over the past 100 years, as big agriculture has systematically pushed small farms to the margins. In the U.S., just four corporations account for anywhere between 50 to 95 percent of seed sales, agricultural chemicals, animal breeding and farm machinery. As these firms have come to control markets, the quality and nutrition in food has decreased, and diets have shifted increasingly to processed foods high in sugars and fats, which earn bigger profits.
“Food is no longer valued for its ability to sustain life,” Walker concludes, “but only for its ability to generate profits.” As the rise of C. auris suggests, such a narrow focus risks sacrificing the effectiveness of some of our most valuable medicines.
Mark Buchanan at email@example.com
Mark Buchanan, a physicist and science writer, is the author of the book “Forecast: What Physics, Meteorology and the Natural Sciences Can Teach Us About Economics.”