In her new book, Maryn McKenna unspools the misuse of drugs, and chronicles how food animals may have created bacteria more resistant to human medicine.

For most people, antibiotic resistance is a hidden epidemic, unless they have the misfortune to contract an infection themselves or have a family member or friend unlucky enough to become infected. Drug-resistant infections have no celebrity spokespeople, negligible political support, and few patients’ organizations advocating for them. If we think of resistant infections, we imagine them as something rare, occurring to people unlike us, whoever we are: people who are in nursing homes at the end of their lives, or dealing with the drain of chronic illness, or in intensive-care units after terrible trauma. But resistant infections are a vast and common problem that occur in every part of daily life: to children in day care, athletes playing sports, teens going for piercings, people getting healthy in the gym.

Forecasting the future of pandemics in 1994.

And though common, resistant bacteria are a grave threat and getting worse. They are responsible for at least 700,000 deaths around the world each year: 23,000 in the United States, 25,000 in Europe, more than 63,000 babies in India. Beyond those deaths, bacteria that are resistant to antibiotics cause millions of illnesses — two million annually just in the United States — and cost billions in health care spending, lost wages, and lost national productivity. It is predicted that by 2050, antibiotic resistance will cost the world $100 trillion and will cause a staggering 10 million deaths per year.