Jenna Ladd| August 17, 2017
As temperatures and humidity rise in the United States, conditions are becoming more favorable for disease-carrying deer ticks.
The U.S. Environmental Protection Agency (EPA) reports that climate change has expanded the geographical range of ticks. Deer ticks specifically are most active when temperatures are above 45 degrees Fahrenheit and humidity is at least 85 percent. As temperatures and humidity rise in many parts of North America, so too are tick populations. The EPA reports that the incidence of Lyme disease in the U.S. has doubled since 1991.
The Northeastern U.S. has experienced the sharpest increase Lyme disease transmission. This part of the country is becoming more humid, making conditions better for ticks to emerge from the ground and latch onto hosts. New Hampshire, Maine, and Vermont have seen the largest spike in Lyme disease incidence since 1991, followed closely by Delaware and Massachusetts. On average, the EPA reports, these states now see 50 to 100 more cases per 100,000 people than they did in 1991.