Lyme disease gets its name from Lyme, Connecticut, the small town where the illness was first identified in 1975. A mysterious cluster of arthritis cases in children and adults caught the attention of researchers, and the town’s name stuck as a label for the disease long before anyone understood what was causing it.
The Outbreak That Started It All
In the early fall of 1975, two mothers from Old Lyme, Connecticut, began reaching out to doctors and health officials about a puzzling wave of arthritis affecting their families and neighbors. Children were developing swollen, painful joints with no clear explanation, and the number of cases was far too high to be coincidence.
Their persistence triggered a formal investigation. Researchers from Yale School of Medicine, led by Allen Steere and Stephen Malawista, launched a surveillance study in December 1975 across three small towns on the eastern bank of the Connecticut River in New London County: Old Lyme, Lyme, and East Haddam. Out of a combined population of just 12,000 people, they identified 51 residents with unexplained arthritis, 39 of them children. That concentration was staggering for such a rare diagnosis. The Yale team initially called the condition “Lyme arthritis,” naming it after the town at the center of the cluster.
As researchers dug deeper, they noticed many patients also developed a distinctive expanding skin rash before the joint problems appeared. The team recognized this rash as the diagnostic hallmark of the infection, and the name gradually broadened from “Lyme arthritis” to “Lyme disease” as more symptoms beyond joint pain came to light.
Europe Knew About It First
Here’s what surprises most people: the disease had been documented in Europe decades earlier, just under different names. A Swedish dermatologist named Arvid Afzelius described the characteristic expanding rash in the early 1900s, calling it erythema migrans. He suspected it was caused by something transmitted through a tick bite. By the 1920s and 1930s, European doctors had connected that same rash to disabling neurological and skin conditions that followed it.
In Europe, the various manifestations carried their own labels. The neurological form was known as Bannwarth’s syndrome. A chronic skin condition linked to the same infection was called acrodermatitis chronica atrophicans. These descriptions date back to the 1880s in some cases. But no one had tied them all together as a single disease with a single cause. It took the dramatic clustering of cases in a small Connecticut town to finally unify these scattered observations under one name.
Finding the Actual Cause
For six years after the Connecticut outbreak, researchers knew the disease existed but couldn’t identify what was behind it. That changed in 1981, when William Burgdorfer, a researcher at the National Institutes of Health Rocky Mountain Laboratories, discovered slim, spiral-shaped bacteria called spirochetes in the guts of deer ticks collected from forests near where infections were occurring. Laboratory testing confirmed these bacteria, passed to humans through tick bites, were the cause of Lyme disease.
The bacterium was named Borrelia burgdorferi in his honor. This discovery also gave the disease its formal medical name: Lyme borreliosis, which is the term more commonly used in European medical literature. In everyday conversation and in most American medical settings, “Lyme disease” remains the standard.
Why the Name Stuck
Diseases named after places have a long history in medicine, from Ebola (named after a river in the Democratic Republic of the Congo) to Rocky Mountain spotted fever. Lyme disease followed the same pattern. The Connecticut town name was simple, memorable, and already embedded in medical literature by the time scientists understood the bacterium and its tick vector. Renaming it would have created confusion, so “Lyme disease” persisted even as knowledge evolved far beyond that initial cluster of arthritic children in New England.
Today, Lyme disease is the most common tick-borne illness in both the United States and the European Union. The CDC estimates that roughly 476,000 people are diagnosed and treated for it each year in the U.S. alone. The tiny Connecticut towns where it all began have a combined population that wouldn’t fill a mid-size concert venue, yet their name is now attached to one of the most widespread infectious diseases in the Northern Hemisphere.