Lyme diseaseHow the Lyme Disease Epidemic Is Spreading and Why Ticks Are So Hard to Stop
I have been following Lyme disease’s spread for nearly four decades. Over that time, Lyme disease cases increased from a few hundred reported in 1982 to more than 33,000 in 2018. The U.S. Centers for Disease Control and Prevention estimates the actual number of Lyme disease cases is about 10 times greater than those reported. Warm weather is arriving and people are beginning to seek outside respite from COVID-19 stay-at-home orders. This is the same time that ticks are beginning to search for their next meal, and the risk of getting Lyme disease rises. Its spread to new areas involves a complex interplay among animals that may aid in helping scientists slow its continuing advance.
In the 1970s, an epidemic of mysterious arthritis-like symptoms began spreading among children in the lushly wooded area around Lyme, Connecticut. Scientists traced the cause to tick bites and named it Lyme disease, but why it had suddenly appeared there was a mystery.
Similar symptoms had been documented on Long Island, New York, years before. Doctors there called it “Montauk spider bite” or “Montauk knee.” It would take until 1990 before scientists found museum specimens of ticks from Long Island and were able to connect the same tick-borne bacteria to both locations and suggest how Lyme disease might have started its modern spread.
As a researcher who studies how disease travels based on geography, I have been following Lyme disease’s spread for nearly four decades. Over that time, Lyme disease cases increased from a few hundred reported in 1982 to more than 33,000 in 2018. The U.S. Centers for Disease Control and Prevention estimates the actual number of Lyme disease cases is about 10 times greater than those reported. For people infected, the symptoms can be debilitating, including fever, fatigue and muscle and joint pain that can last for months or years after treatment, and in some cases cause neurological disorders and heart infections.
Warm weather is arriving and people are beginning to seek outside respite from COVID-19 stay-at-home orders. This is the same time that ticks are beginning to search for their next meal, and the risk of getting Lyme disease rises. Its spread to new areas involves a complex interplay among animals that may aid in helping scientists slow its continuing advance.
No Forests, No Deer, No Lyme
Lyme disease has existed in North America and Europe for a long time and must have affected American Indians and early colonists. But only recently has it become epidemic.
One reason Lyme disease may have remained obscure in the United States for so long before beginning to spread in the late 20th century had to do with the extensive deforestation to create farmland that began after colonists arrived in North America. With the loss of forests, deer disappeared from most of the Northeast. The only known populations in the Northeast were in the Adirondacks and on Long Island. Without deer, deer ticks, also known as black-legged ticks, were rare, and the bacterium that causes Lyme disease was contained in isolated tick populations, primarily in northern Wisconsin and on Long Island.
That changed when deer were reintroduced for hunting in the Northeast during the early 1900s
