Author: Deanna Cannizzaro

My mother often reminisced on how she practically lived in the woods. Traversing through creeks and trees in shorts and a tank top was considered a typical day back in the 1970s and 80s. When I go into the woods, I’m covered head to toe in long pants, high socks, and a long-sleeved shirt despite the 90-degree weather.

“Weren’t you worried about ticks?” I asked back in 2010, appalled that she never checked for tick bites after her adventures. 

She shrugged and stated, “I swear, ticks weren’t a thing 30 years ago.”

No one particularly enjoyed the sensation of expert hiders crawling on their skin, but the only trace it left was some itchiness. Of course, it wasn’t only about finding a tick buried under skin but what they can carry – Lyme disease. Lyme disease now affects nearly 500,000 Americans annually and is caused by bacteria that some black-legged ticks carry. Without timely diagnosis and treatment, the disease can lead to detrimental neurological and immunological health problems.

"It's a debilitating disease and extremely dangerous. You can't play around with it, so you've got to check yourself for ticks."

                                               - Shania Twain

I wondered if in the 1970s and 80s if ticks had been around, but the Lyme bacteria wasn’t. A lack of disease could explain the lackadaisical attitude towards ticks. 

My idea was quickly proven wrong.

Fossils of tick species have been found from 100 million years ago, and the bacteria is at least 60,000 years old. Though ticks and Lyme bacteria have existed for an extended period of time, it wasn’t until 1976 that Lyme disease was officially identified in Lyme, Connecticut.

The disease miraculously traveled across the country from this isolated case in the northeast. Despite the Lyme bacterium and ticks coexisting for years on end, the reason for why Lyme disease tripled since 1995 was yet to be uncovered.

I wasn’t the first or only person to consider this conundrum. Katherine Walter at Yale University investigated the spike of Lyme disease in humans by delving into the genome, or full set of DNA, of the Lyme bacteria [5]. Before 19XX,  scientists thought that the Lyme bacteria had mutated, or changed, over time to become more infectious, but Walter’s research showed that wasn’t the case. The Lyme disease epidemic was not sparked by a new genetic variant of the bacteria, but from environmental shifts in North America. 

Environmental conditions and human industrialization inadvertently contributed to the increase of Lyme disease. As deer populations grew and spread from their forested homes into suburban areas, so did the ticks that feed off them. The deer explosion in the 20th century was initiated by deer hunting regulations and the decline of  wolf predators. These dynamics changed the food chain, allowing black legged deer ticks which carry the bacteria to invade in high numbers. New landscapes that alter interactions among species influence human lives more than one would think. 

The deer explosion may explain the rapid expansion of ticks, but how the Lyme bacteria followed in close succession remained in question. Ticks are not born carrying the Lyme bacteria, nor can they pass it to each other. Interestingly enough, it all comes down to an unexpected, but critical species that harbors the Lyme bacteria: the white-footed mouse.

While deer can carry ticks, it’s actually the white-footed mouse that is most responsible for infecting ticks with the Lyme bacteria. As ticks spread into suburban areas, they came into contact with more animals such as birds and white-footed mice. Young ticks often feed on these mice, which increases the chance that they would pick up the Lyme bacteria. 

Lyme disease has indeed risen in the past few decades, but not due to DNA changes or mere coincidence.Ticks do not have mal intent; they don’t realize they are infected.. A tick bite itself may itch, but the effects are short lived, like a mosquito bite. Ticks simply desire to feed on our blood, but they can unknowingly pass the Lyme bacteria into our bloodstream through their saliva, making their role in spreading the bacteria a serious concern for anyone venturing outdoors.

My mother was half-right, it seems. There were ticks back in the 1970s and 80s, but they rarely carried the Lyme bacteria. No one was overly worried about ticks– they gave annoying bites, but were not the efficient disease vessels they are today. Now, protecting oneself from tick bites is critical for human health and there are safe and effective measures to lower one’s risk. 

In the end, I will continue to sweat in long pants and long socks while hiking in the summer heat - and look a little funny while doing so.