Lyme disease is caused by the bacterium Borrelia burgdorferi and is transmitted to humans through the bite of infected blacklegged ticks. Stegerphoto | Getty Images

In the midst of relaxing summer days and long-awaited vacations, there's a tiny enemy that's causing oversize worry: ticks. Blacklegged ticks infected with the Lyme disease bacterium Borrelia burgdorferi are wreaking havoc in the northeastern, mid-Atlantic, and north-central states, as well as the West Coast, particularly in northern California. Lyme disease accounts for more than 80 percent of tick-borne diseases and, even if caught and treated, can cause long-lasting and debilitating symptoms. In May the Centers for Disease Control and Prevention reported that the number of people getting diseases from ticks, mosquitoes and fleas has more than tripled in the United States, with more than 640,000 cases reported during the 13 years from 2004 through 2016. In just the past year, celebrities Kelly Osbourne and The Real Housewives of Beverly Hills star Yolanda Hadid both released memoirs detailing their agonizing struggle with the disease and why it took so long for doctors to diagnose it. In fact, before finally testing positive for Lyme, Osbourne's doctors told her she had epilepsy. But there are glimmers of hope, experts say. New tests to more accurately detect Lyme are in the works, including one that uses a urine sample to more quickly detect the presence of the bacteria that causes the disease. And last year a French company, Valneva, received fast-track status from the FDA for a vaccine for Lyme disease. In the meantime, Lyme is affecting more people and is spreading to more states across the country. If left untreated, the disease can cause fever, fatigue, joint pain and eventually damage to the nervous system and heart. Fourteen states in the Northeast and upper Midwest, including Minnesota, Michigan, Maine and New Hampshire, have the greatest number of reported cases, according to the CDC, but nearly every state has been touched by it. Researchers at the CDC say there are several reasons why Lyme is on the rise. For starters, we're a more mobile society. As goods and humans increasingly move around the world, ticks travel with them, introducing the disease to new locales quickly. Couple that with environmental changes, like global warming, and woefully inadequate prevention efforts on both the federal and state level, and it's no wonder why Amy Schwartz, an epidemiologist with the CDC's division of vector-borne diseases, said Lyme disease is "not going away anytime soon."

A national health crisis

Making the disease even harder to battle, researchers say, is the fact that it is vastly underreported. Schwartz said about 30,000 cases of Lyme disease are reported in the United States each year (up from 10,000 a year in 1998), but about 300,000 cases annually are actually diagnosed, triple the amount from two decades ago. She said doctors are required to report cases of Lyme disease to their local health departments, but admits "that doesn't always happen." Dorothy Leland, vice president for education and outreach at LymeDisease.org, a patient advocacy group, discovered that. She claimed that in 2005 her then 13-year-old daughter became quite ill. Doctors couldn't figure out the cause but ruled out Lyme because they told her the disease wasn't present in her home state of California. It took another year until Leland's daughter was diagnosed, but by then the teenager was so debilitated she spent three years in a wheelchair. "They wouldn't even go down the path of considering that it could have been Lyme, because they said it didn't happen in California," she said. The other challenge with Lyme is that the available tests for it are not always accurate. As a result, people who have been bitten often suffer for months or, in the case of Hadid and Osbourne, for years until properly diagnosed. Here's why: The current blood test for the disease relies on detecting antibodies. Those are the proteins the body's immune system produces to fight the disease. The test doesn't detect the disease itself. The problem with this, said the CDC, is that a person isn't likely to test positive for Lyme until they've been infected for anywhere from four to six weeks. That's why doctors who suspect a patient has Lyme disease based on symptoms (rash, joint pain, and fatigue among them) should prescribe antibiotics even if the test is negative in the beginning.

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