The writer visits a farm in the town of Lyme, Conn. with a group of biologists to learn what’s driving the population of pathogen-laden ticks:

It’s startling to look at the graphs of tick-borne diseases over the past few decades. They’re mostly going in the wrong direction. The research on Lyme disease is fairly recent, sparked in the mid-1970s after a cluster of children around Lyme developed fever and aches. They were diagnosed with juvenile arthritis—a peculiar diagnosis for so many children in one place. Their parents searched for an explanation, and eventually Allan Steere, a doctor at Yale, figured out that they suffered from an infectious disease. The fact that they all came from a rural part of the state suggested that an insect or some other animal had delivered the infection. In 1982, Willy Burgdorfer, an entomologist with the National Institute of Allergy and Infectious Diseases, discovered corkscrew-shaped bacteria in black-legged ticks from Long Island. He exposed the bacteria to serum from people with Lyme disease and discovered that their antibodies swarmed around the microbes. That was a sign that these bacteria—which would later be named Borrelia burgdorferi after him—were the cause of Lyme disease.