But half of Lyme sufferers don’t recall a tick bite, according to the Centers for Disease Control and Prevention (CDC) in Atlanta. (McCarthy, for example, doesn’t remember getting one.) So doctors try to diagnose early Lyme by looking for telltale symptoms like a red rash—which shows up in 70 percent to 80 percent of people with Lyme; it doesn’t always appear as the characteristic bull’s-eye—or flu-like symptoms such as fever, fatigue and joint pain.
Still, even calling it Lyme oversimplifies things, because species of closely related bacteria can cause the disease. In February, scientists from the Mayo Clinic in Rochester, Minnesota, announced that they’d discovered an entirely new bacterial species causing the disease in the Midwest. It brings on symptoms like extreme drowsiness and vomiting—things doctors don’t typically associate with Lyme.
Adding to the confusion is the fact that a single tick can carry more than one species of Lyme-causing bacteria at the same time. Ticks often carry other pathogens, too, which can require additional diagnostic tests and treatments.
Lyme affects women differently.
Infected ticks are equally likely to latch on to men and women, but research suggests women may be less likely to test positive for the infection once they have it. One study found that 50 percent of men with Lyme disease test positive, but only 32 percent of women do. That’s because women may produce less of a Lyme-bacteria-fighting antibody called immunoglobulin G, which is often used to diagnose the infection. But experts aren’t sure why. The longer it takes a doctor to diagnose Lyme—she may suspect stress or a viral infection, like McCarthy’s did during her ER visit—the greater the delay in prescribing antibiotics to treat it and the harder it may be to cure. Research shows even after they’re treated, women are more likely than men to develop the lingering symptoms known as posttreatment Lyme disease syndrome (PTLDS).