Almost 80% of all antibiotics in the United States aren’t taken by people. They’re given to cows, pigs, and chickens to make them grow more quickly or as a cheap alternative to keeping them healthy. These drugs could give rise to superbugs—bacteria that can’t be treated with modern medicine—and things are only getting worse. In 2013, more than 131,000 tons of antibiotics were used in food animals worldwide; by 2030, it will be more than 200,000 tons.
In a paper published today in Science, epidemiologist Thomas Van Boeckel of the Swiss Federal Institute of Technology in Zurich and colleagues outline the growing threat—and what can be done about it. Boeckel spoke to us about his team’s work. This interview has been edited for clarity and length.
Q: What are the threats posed by the overuse of antibiotics in food animals?
A: Most antibiotics are used either to prevent disease or to promote growth, and this means exposing healthy animals to antibiotics over long periods of time. If the bacteria that colonize these animals acquire [antibiotic] resistance genes, treatment becomes ineffective: That’s a threat for the livestock sector because you can’t keep your animals healthy. But bacteria in the animals’ gut can also transfer the resistance genes to microbes harmful to humans. We don’t know the magnitude of this process, but given the large amount of antimicrobials used in animals we have good reason to be concerned. [In 2013, researchers showed that people living near pig farms or crop fields fertilized with pig manure are 30% more likely to become infected with methicillin-resistant Staphylococcus aureus bacteria.]
Q: What was the motivation behind your study?
A: Most countries have taken baby steps to limit the use of…