Again, scientists don’t know why women are at a higher risk for this condition. “It may have something to do with women’s immune responses,” says John Aucott, M.D., assistant professor in the division of rheumatology at Johns Hopkins Medical School in Baltimore. Our immune systems may make us more prone to PTLDS’s vague but long-lasting symptoms—fatigue, aches and pains, and cognitive problems—which are similar to those of chronic fatigue syndrome and fibromyalgia, two additional conditions women are more likely to suffer from.
And it’s on the rise.
The number of reported cases of Lyme disease in the United States has grown about 70 percent during the past decade. And although Lyme is most rampant in the Northeast and Midwest—experts estimate that 85 percent of cases originate in these regions—it was reported in 45 states in 2014.
With each passing year, Lyme becomes more of a threat for a number of ecological reasons. When the United States shifted its focus from agriculture to industry about 150 years ago, an estimated 80 percent of farmland regrew into forest. This has allowed mice and rodents to flourish—and it’s where ticks pick up Lyme causing bacteria.
Some scientists believe that climate change is also causing ticks to spread north to areas that used to be too harsh for them, and it’s changing their behavior—some now emerge sooner in the spring and summer. In parts of the Midwest and Northeast, up to 50 percent of adult ticks now carry the infection, and these Lyme hot spots are growing: According to a 2015 CDC study, the number of U.S. counties at high risk for human Lyme disease approximately tripled from 1993 to 2012. “Now that the environment has been disturbed by us,” says Sam Telford, S.D., a tick-borne-disease specialist at Tufts University, “we see far more ticks than would ever be natural.”