John Carroll University Professor Colin Swearingen is in healthy shape, usually going on runs multiple times a week and staying active with his family. Naturally, it came as a great surprise when he started noticing last October that he couldn’t get past three minutes of continuous running when he was used to doing a full two miles without stopping. 

“It’s just that I couldn’t go on, and it got worse,” he recalls in an interview. 

Around the same time in mid-October, Swearingen was experiencing symptoms such as chills, night sweats and headaches, all of which are common for many conditions. He then began feeling that his pulse was very irregular and decided to go to the emergency room on the advice of an on-call nurse. After a series of tests and physician consultations, he was diagnosed with Lyme carditis, a rare form of Lyme disease that infects the heart. According to the Centers for Disease Control, this occurs when bacteria enters the heart tissue and interferes with normal electrical signals, causing heart palpitations or irregular beats.

Lyme disease is caused by a bacterium known as Borrelia burgdorferi that is harbored in ticks, specifically the blacklegged tick in the Northeast region of the United States and into Canada. These ticks are usually found on white-tailed deer, presenting a complicated interplay of vectors—the name scientists give to creatures that carry the disease. Lyme disease is just one example of a vector-borne disease that impacts human health and is becoming more of a concern due to climate change. 

Many experts have concluded that the warming temperatures of climate change are causing the range of these ticks to move northward, so researchers like Mark Nelder and a team at Toronto Public Health and the University of Toronto have done extensive studies to investigate the risk this poses to human health. 

John Brownstein et al. of the Yale School of Medicine, in a 2005 article published in the journal of Ecohealth, used a model that predicted that by 2080, the tick population will move northward through Canada as suitable habitat increased by 213%.

In Ohio specifically, experts have already seen an increase in cases in the past three to four years. Dr. Amy Edwards, a pediatric infectious disease specialist at Rainbow Babies and Children’s Hospital in Cleveland, said, “I would say we see [Lyme disease] more now than we used to. We used to go a whole year without seeing it.” 

Epidemiologist Lynn Denny from the Ohio Department of Health, stated, “In 2018, we had under 300 cases reported for the year, specifically 293. In 2021, we had 583, which is the most reported in the state.” 

These numbers speak for themselves in terms of hard evidence of rising cases of Lyme disease. 

The Ohio Department of Health has teams that track tick numbers throughout the state, and they are finding increased numbers of ticks which can explain the increased number of Lyme disease cases. Richard Gary, the zoonotic disease program manager for the department added that, although rising temperatures due to climate change are causing the increased range of ticks, there are other factors like habitat improvement or restoration that allow regrowth of woodlands and creatures and allow the white-tailed deer populations to increase. This lends to increased ticks and a greater risk for Lyme disease. 

On the other end of the spectrum, fragmentation of forests and tick habitats can also lead to increased human exposure to Lyme disease. David Quammen, a science journalist and author with expertise in zoonotic diseases, explained in an interview that in the suburbs, the landscape becomes fragmented into smaller strips of greenspace that can only support smaller animals like mice and squirrels. These animals are then able to come in closer contact with humans and can also harbor the blacklegged tick with Borrelia burgdorferi. 

Edwards shared that as humans are taking up more areas of the Earth, we are living more intimately with animals than we used to and therefore expect to see a rise in “zoonoses,” that is, diseases transmitted by animals to humans. 

Although he is an Ohio resident, Swearingen reported that he was playing disc golf in a wooded area in western Pennsylvania when he was most likely exposed to a tick bite harboring the bacteria that caused his Lyme carditis. Pennsylvania and New York have higher reported cases of Lyme disease than Ohio, so it was interesting to hear from Denny that the majority of Lyme cases reported to the Ohio Department of Health are by those who have traveled within their home county or within the state of Ohio. There are still cases reported after travel outside the state, like Swearingen’s, but these are not the majority. 

Denny also emphasized that most people diagnosed with Lyme never knew they were exposed to a tick, which was Swearingen’s experience. He could only conjecture, with the help of his infectious disease physician, that the onset of symptoms matched up with the timing of his trip to Pennsylvania. This element of surprise is a reminder to know the risks of tick bites and how to prevent them.

Another factor that can influence exposure to Lyme disease is the time of year. The blacklegged tick is active all year round, though Denny from the Ohio Department of Health stated that in “June through August the majority of our cases are reported.” She suspects this is because during the warmer months people are outdoors more and in the vicinity of tick populations. 

Additionally, the nymph stage, when ticks are immature, is also the stage at which humans are infected most often. According to the Ohio Department of Health, nymphs typically feed during the spring and summer months, explaining the increased number of cases during that time of year. 

Since Lyme disease is a bacterial infection, it is treated with antibiotics. Edwards reported that she typically prescribes doxycycline to treat Lyme disease cases. There are usually no long-term effects of having Lyme disease, though the sooner it is diagnosed and treated, the better. 

Swearingen was treated with IV antibiotics for eight days, which is slightly longer than the typical case. He said his infectious disease physician explained that it’s possible to have some lingering effects. It has been about five months since his diagnosis and he said, “I don’t think I’m one hundred percent, but I don’t think I’m far off either.” 

Having long-term side effects after Lyme disease is a controversial topic with those on both sides having strong opinions. Edwards explained that a condition known as “chronic Lyme” is claimed to be a type of post-infection syndrome. However, she strongly emphasized that there is no scientific evidence for this condition. 

Quammen explained that he met many people who said chronic Lyme has destroyed their lives and gone on for many years, finding niche doctors that will treat it for an extended period with supplements and such. He strengthened Edwards’ claim that it has not been backed up by any scientific evidence. 

Lyme disease may seem scary, but there are simple ways to prevent tick bites which will prevent the bacterial infection causing the disease. Edwards advises to use insect repellent that has DEET in it. The same products typically used to prevent mosquito bites can be used to prevent tick bites. 

Gary warned, “We’re now getting into the season where most of our tick diseases occur.” He agrees that one consistent recommendation is to use repellent if you are going to be outside and active. 

Denny adds that after coming in from the outdoors, one should do a tick check and take a shower. Ticks usually go to moist and dark places so making sure to check those areas of the body is crucial. Gary adds that it is important to check areas where your clothing is tight to the skin as ticks are often found there as well. 

If Swearingen had been more aware of the area he was in and his possible tick exposure, he could have been more careful about checking for ticks and used Denny’s and Gary’s advice to avoid contracting Lyme disease. Despite the burdens he suffered through, he reflected that he could have had it much worse if he hadn’t detected it when he did.

“I feel fortunate that I was able to ask the right questions and see the right people and get the right treatment,” Swearingen said.