Most of us have heard of Lyme disease, and many of us know someone who’s been diagnosed with the disease. But health officials say that our awareness of Lyme disease is about to go up – and it’s not because people are suddenly becoming interested in vector-borne diseases.
According to a series of recent reports, the harsh winter did nothing to cull the nationwide tick population, and health officials are primed for summer to bring a rapid increase in the number of tick-borne diseases. And even more disturbing is that the uptick (see the pun there?) in these illnesses is thought to be due, at least in part, to climate change — which means that this trend will only get worse in coming years.
Tick Talk: A Brief Background on Tick-Borne Diseases
Lyme disease, named after the towns of Lyme and Old Lyme, Conn., where a number of cases were first identified in 1975, is recognized as a disease that was often misdiagnosed and widely under reported by physicians. The Centers for Disease Control and Prevention previously recorded the number of diagnosed and probable cases at around 45,000 annually.
While this is a large number when compared to other vector borne diseases like West Nile virus, a landmark moment in the history of Lyme disease came in August 2013 when the CDC announced that the real number of Lyme disease cases nationwide probably approaches about 300,000 annually.
Although Lyme disease is by far the most common tick-borne disease, the insects can spread a huge array of diseases including Q fever, Colorado tick fever, Rocky Mountain spotted fever, African tick bite fever, tularemia, tick-borne relapsing fever, babesiosis, ehrlichiosis, tick paralysis, and tick-borne meningoencephalitis.
Tick-borne diseases are found in many areas across the country, but they’re often clustered in specific regions. Rocky Mountain spotted fever, for instance, occurs mainly in the mid-Atlantic and southern states. Lyme disease is found mainly in the Northeast and upper Midwest, but cases have been reported in nearly every state.
Deer ticks, also called “blacklegged” ticks, tend to live in moist and humid environments, particularly in or near wooded or grassy areas. These ticks are the ones that carry Borrelia burgdorferi, the bacterium that causes Lyme disease.
While all ticks are small creatures, deer ticks are especially tiny. The young “nymphs” are only the size of poppy seeds — and these are responsible for the vast majority of Lyme disease infections. While adult ticks can transmit the disease, most humans are infected through the bites of nymphs, which are most active during the spring and summer. Their small size makes them particularly difficult to detect, and often they attach to the body in hard-to-see areas such as the groin, armpits, and scalp.
“Ticks can be so tiny that most people who get Lyme disease don’t recall a tick bite,” says Dr. Adriana Marques, a Lyme disease expert at NIH. But if you have symptoms of the disease, she says, “the earlier you get treated, the better.”
Tick-borne diseases tend to share certain symptoms. Symptoms can include fever, headache, muscle or joint pain, and extreme fatigue. People with Lyme disease usually get an expanding red rash that sometimes resembles a bull’s-eye. “The rash is usually tender, not painful or itchy, so people may not realize they’re sick,” says Marques.
When it’s caught early, Lyme disease usually responds well to antibiotics, and full recovery is typical. However, if left untreated, the infection can spread and cause a variety of symptoms, some of which can be quite severe and even debilitating. Even with antibiotics, an estimated 25 percent of those infected with Lyme disease experience lingering symptoms. Some people may develop nerve problems, arthritis, migraines, cognitive impairment, or other chronic conditions.
Explaining the Uptick
Over the past two decades, marked increases have been reported in the abundance of ticks and the incidence of tick-borne disease in North America and Europe. While some of these changes have been attributed to an increase in awareness of tick-borne diseases and increased abundance of wild tick hosts (principally deer), there is evidence that the increases in tick-borne diseases are being driven by climate change.
A federal report released last week said climate change could bring warmer winters that make diseases like Lyme more prevalent. The impact of climate change on tick-borne diseases was also highlighted in a recent report from the Intergovernmental Panel on Climate Change, which noted that the number of cases of Lyme disease, and the ticks that carry it, will continue to spread along “climate-determined trajectories.”
Climate change affects tick populations and tick-borne diseases in two major ways: it allows ticks to expand their geographical boundaries and also increases the survival of ticks through the winter season, thereby increasing their numbers as well as their distribution. With more ticks in more places, the incidence of tick-born diseases naturally goes up.
The increase in Lyme disease is most severe in certain states in the Northeast. In Vermont, for example, confirmed cases of Lyme disease numbered just 12 in 2000 — that figure increased to a staggering 500 in 2013. Maine has also experienced marked increases in Lyme disease cases: in 2013, the state documented 1,376 confirmed cases, nearly double the number of cases they had in 2010. Connecticut, New Hampshire, Delaware, Massachusetts, Pennsylvania, New Jersey, and Wisconsin, states where the incidence of Lyme disease is already high, have also reported growing numbers of cases in recent years.
However, even states not typically affected by Lyme disease are also seeing increases in the incidence of tick-borne diseases. In Tennessee, for example, health officials have been documenting a higher incidence of certain tick-borne infections like rickettsiosis and ehrlichiosis. This spring, the Tennessee Department of Health reported a 500 percent increase in tick-borne rickettsiosis.
Researchers are also discovering new tick-borne bacterial infections that have never before been documented. Borrelia miyamotoi, a bacterium closely related to the one that causes Lyme disease, has been detected in species ticks for years — but it wasn’t until 2011 that the first human cases of the bacterial infection were reported. While the initial cases were found in Russia, a 2013 study discovered that the disease may be shockingly common in the United States. Among people with symptoms of Lyme disease, over 20 percent tested positive for Borrelia miyamotoi infection, suggesting that the prevalence is much higher than previously thought.
While these trends may be driven by a number of factors, most scientists agree that climate change accounts for a significant proportion of the increase in tick-borne diseases. And experts say the trend will only get worse. One recent study estimated that the current geographic distribution of tick-borne illnesses will double in the next few years if the climate trajectory stays the same — meaning that people living in areas that rarely see tick-borne diseases will start to see a rapid increase in cases. The same study also found that climate changes are creating alterations in the life cycle of ticks, which will lead to more effective disease transmission. This means that the chances of getting infected from a tick bite will increase dramatically. Taken together, these changes are predicted to cause a significant and rapid rise in the number of cases of tick-borne infections in the U.S. and elsewhere.
So hopefully I’ve convinced you that tick-borne diseases are something to think about. But now that you know your risk of these infections is greater than ever, you probably want to know what to do about it!
Of course, the best way to avoid Lyme and other tick-borne diseases is to prevent tick bites in the first place. Help keep ticks off your skin by wearing long sleeves, long pants, and long socks. You can also ward off ticks by using an insect repellant that contains at least 20% DEET (for the skin) or permethrin (for clothes). To avoid ticks, walk in the center of trails and steer clear of tall vegetation.
If you’ve been in an area where ticks are common, bathe or shower as soon as possible, and wash or tumble your clothes in a dryer on high heat. Check your body carefully for ticks, focusing on areas under your arms, in and around your ears, behind your knees, on your scalp, and any other areas where a tick may be able to hide. Performing these ticks right after you come inside is important — they dig and burrow into the skin before they bite and feed, so finding them early is key. Removing ticks right away can help prevent disease — but be careful when trying to remove a tick. If you don’t remove the entire tick, the ‘head’ of the insect can remain attached to your skin and continue transmitting bacteria.
To remove a tick:
- Use fine-tipped tweezers.
- Grab the tick close to the skin and gently pull upward to remove the entire tick.
- Don’t use home remedies like petroleum jelly, nail polish, or a lit match to try to detach ticks.
- After removing the tick, clean the bite area and wash your hands thoroughly.
If you develop a rash, severe headaches, or fever within weeks of removing a tick, see your doctor.
And don’t forget about your pets! Prevent family pets from bringing ticks into the home by limiting their access to tick-infested areas and by using veterinarian-prescribed tick collars or spot-on treatment.
Finally, don’t underestimate the potential damage that a small tick can cause. Although most cases of Lyme disease are successfully resolved with antibiotics, a small but significant proportion of those infected with the disease report long-term symptoms ranging from dizziness, muscle aches, and minor “brain fog” to intense pain, overwhelmingly fatigue, mood disorders, and severe memory problems.
Often called “chronic Lyme disease,” the official term for these persistent symptoms is Post-Treatment Lyme Disease Syndrome (PTLDS). The exact cause of PTLDS is not yet known. Most medical experts believe that the lingering symptoms are the result of residual damage to tissues and the immune system that occurred during the infection. Similar complications and “auto–immune” responses are known to occur following other infections, including Campylobacter (Guillain-Barre syndrome), Chlamydia (Reiter’s syndrome), and Strep throat (rheumatic heart disease). Some health care providers believe that these symptoms reflect persistent infection with Borrelia burgdorferi, the bacterium that causes Lyme disease, but the evidence is inconclusive.
If you have been treated for Lyme disease and still feel unwell, see your doctor to discuss how to relieve your suffering. Your doctor may want to treat you in ways similar to patients who have fibromyalgia or chronic fatigue syndrome. While this may be frustrating, there is currently no consensus on the best course of treatment for PTLDS.
If you want to learn more about PTLDS, or if you think you may be suffering from persistent symptoms of Lyme disease, a good place to start is the International Lyme and Associated Diseases Society. You may also want to check out the American College of Physicians’ patient’s guide to Lyme disease.
Here’s to a happy, healthy, and tick-bite-free summer!
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