The Lyme Epidemic Is Worse Than Ever

Prevention is the best medicine for Lyme disease—but we’ve got our work cut out for us as climate change gives ticks a warm welcome.

A black-legged tick

Credit: Juniors Bildarchiv GmbH/Alamy

In the summer of 2013, I was changing into pajamas when an irritated blotch of skin caught my eye. My rib cage looked like a miniature advertisement for Target: There was a near-perfect ring of red, a smaller, concentric ring of clear skin, and then a red dot right in the middle. Bull’s-eye.

Symptoms of Lyme disease

In medical jargon, this distinctive bull’s-eye rash is called erythema migrans, and it’s the calling card of Lyme disease. The disease is spread by a specific parasite, a black-legged tick infected with a bacterium called Borrelia burgdorferi or B. burgdorferi (Lyme is not contagious through human-to-human contact). The rash appears at the site of the tick bite in the days or weeks after the exposure. Fittingly enough, I was spending this particular peak tick season in Old Lyme, Connecticut—where the disease was first described in 1975. Luckily, I knew to be on the lookout for this exact symptom, and a course of antibiotics knocked it out of my system. I experienced no further problems.

While Lyme disease usually responds well to early treatment, cases aren’t always as straightforward as mine was. According to the Centers for Disease Control and Prevention (CDC), somewhere around a quarter of infected people never get the bull’s-eye rash, and other early signs—fever, headache, fatigue, and achy muscles—can be easy to misinterpret. If Lyme progresses untreated, it can spread to the joints, heart, and nervous system, sometimes triggering problems such as meningitis, arrhythmias, or temporary facial paralysis. Later stages of the disease can cause symptoms that are more difficult to treat, like arthritis and memory loss.

A quarter of Lyme-infected patients never see the bull’s-eye rash that is a sign of the disease.
Credit: KC Shields/Alamy

The spread of B. burgdorferi

Worryingly, more and more people are experiencing Lyme’s ravages as environmental conditions help black-legged ticks—and, by extension, the disease-causing B. burgdorferi bacteria—spread into new areas.

“It’s a huge problem, it’s growing, and we really are concerned about the lack of prevention tools that are available,” says C. Ben Beard, deputy director of the CDC’s Division of Vector-Borne Diseases.

Unlike the tiny ticks that carry the troublesome bacteria, Lyme’s rise is easy to spot in the CDC’s incidence maps from the past couple of decades. Since the early 1990s, the annual number of officially reported cases of Lyme in the United States has more than tripled to about 35,000, but recent estimates say the actual number of people diagnosed and treated for the disease each year is more than 13 times higher than that—close to 476,000. Climate change, suburban land development, and habitat change are creating conditions that not only allow the ticks to thrive, but also put more people into contact with them and their harpoonlike mouthparts.

Black-legged ticks (also known as deer ticks) feed exclusively on blood and need three meals over a two-year period to complete the four stages of their life cycle; otherwise, they starve to death (good riddance). As winters warm, milder seasons are giving the bloodsuckers a larger window of opportunity to find hosts to dine on, allowing them to survive in greater numbers. Meanwhile, higher temperatures are enabling the ticks to spread to parts of the map that have historically been too cold to sustain them. (These arachnids also depend on a high baseline of relative humidity, which explains why residents of drier regions of the country don’t have to worry about the disease.)

A black-legged tick’s four stages life
Credit: Pamela Freeman

Climate change isn’t the only thing humans are causing to make the environment more hospitable to these parasites. Forest fragmentation is giving a boost to populations of white-footed mice, the primary carriers of B. burgdorferi, and suburbanization puts humans into closer contact with these and other tick-hosting wildlife, like chipmunks and deer.

Almost half of all U.S. counties reported the presence of black-legged ticks as of 2015, up 45 percent from 1996. Still, Lyme is mostly a regional threat—more than 90 percent of cases occur in states in the Northeast, mid-Atlantic, and upper Midwest. And within those states, Lyme is sickening more and more people. The upsurge is especially pronounced in the Northeast, where the number of counties with high incidence of the disease increased 320 percent between 1993 and 2012. Canadian doctors are also seeing more patients with the disease: In 2017, Lyme cases in Ontario had tripled compared to their five-year average between 2012 and 2016.

Getting treatment for Lyme disease

As Lyme moves into new communities, residents often don’t know how to protect themselves, and local doctors aren’t always familiar with the symptoms and best treatment practices. On top of that, bad advice on how to treat Lyme is swirling around on the Internet. According to one study, more than 30 untested alternative therapies are marketed to Lyme sufferers online, including drinking urine, sleeping on a bed of 70 magnets, and blowing gaseous ozone into the rectum. Yup. (Just to be crystal clear: Do not try any of these at home…or anywhere else.) “The misinformation persists at almost all levels of the Lyme epidemic,” says Richard Ostfeld, a disease ecologist at the Cary Institute of Ecosystem Studies. Beard stresses the importance of seeing a health-care provider right away if you start feeling sick within a few weeks of a tick bite—especially as Lyme isn’t the only tick-borne disease.

Richard Ostfeld tags a white-footed mouse as part of field research on the ecology of Lyme disease.
Credit: Pamela Freeman

Combine inadequate prevention with serious—but sometimes enigmatic—symptoms, widespread misinformation, and a steady creep into new areas, and you’ve got a recipe for a population increasingly vulnerable to a Lyme epidemic. “I would characterize our preparedness as very poor,” says Ostfeld. “And that needs to be rectified.”

Advances in Lyme prevention

So what can be done? A lot, actually. Beard says the CDC is working to educate health-care providers in Lyme-prone areas on how to recognize the symptoms. The National Institutes of Health is also supporting research into more rapid diagnostic tests. The current approach detects antibodies that the immune system produces in response to the bacteria, but the antibodies can take a few weeks to show up.

Ostfeld thinks diagnosing Lyme will remain difficult for some time, and avoiding infections in the first place may still be the best strategy. Black-legged ticks need to be attached to the body for at least 24 hours before they can transmit Lyme. For people who live in Lyme hot spots, that makes wearing proper clothing (we recommend long pants tucked into your socks), steering clear of the tall grass and brushy areas where ticks love to lurk, conducting daily tick checks, and showering soon after returning from the outdoors particularly impactful. “What if we lived in a world in which [diagnosis] was less important because we were preventing so many potential cases of tick-borne disease?” Ostfeld asks.

Clinical trials are currently underway to investigate additional tools for prevention. In 2017, the FDA fast-tracked the approval process for VLA15, a potential Lyme disease vaccine that’s expected to enter Phase 3 clinical trials later this year. (A pharmaceutical company discontinued an earlier vaccine, introduced in 1998, after some recipients claimed it gave them arthritis. Clinical data did not support these claims; the same vaccine is now used to protect dogs from Lyme disease.) Meanwhile, researchers from UMass Chan Medical School are working on Lyme pre-exposure prophylaxis (or PrEP) in the form of a seasonal shot that delivers a Lyme-fighting antibody directly to the patient.

Lyme disease’s climate connection

On a larger scale, curbing the climate crisis and other environmental forces that drive Lyme disease and other vector-borne illnesses, like the Zika virus and malaria, into new areas could be critical. The Fourth National Climate Assessment warns that climate change is projected to alter the distribution of disease-carrying insects, including ticks, and the U.S. Environmental Protection Agency categorizes Lyme disease as a “climate change indicator” in the United States.

“We absolutely need to be pushing our leaders at all levels of government to cut carbon pollution,” says Juanita Constible, senior advocate for climate and health for NRDC’s Climate & Clean Energy program. “We’re setting up the backdrop for ticks to take over parts of the country where they never were before.”

Constible speaks from the heart. She lives in Loudoun County, Virginia, a Lyme hot spot, and has had the disease three times in the past decade. And though Constible has made a full recovery after each bout with Lyme, the experiences have left their mark on her work. “It makes it deeply personal for me, and it heightens the urgency to do something about climate change,” she says. “I certainly don’t want my friends and family and coworkers to face this.”

This story was originally published on April 9, 2018, and has been updated with new information and links.

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