On a sweltering, sunny day this summer, Emory University researcher Arabella Lewis made her way through the brush in a patch of woods in Putnam County, Georgia, about an hour southeast of Atlanta. She was after something most people desperately try to avoid while in the woods: ticks.
“Sometimes you have to get back into the weeds to get the best ticks,” she explained as she swept a large square of white flannel along the forest floor.
The idea was that the ticks could sense the movement of the fabric and smell the carbon dioxide that Lewis exhaled and would grab onto the flannel flag.
“My favorite thing about them is their little grasping forearms, the way they want to swing them around, like they’re trying to grab onto things,” says Lewis, who has been fascinated by ticks since she was a young child growing up. a farm – and constantly dealing with ticks. “They have these little organs on their hands that smell, so they smell with their hands.”
As soon as a tick jumped aboard her flannel, Lewis picked it up with the tweezers she wore around her neck and deposited it in a labeled vial. Back at the Emory lab, she would test ticks for the Heartland virus.
The tick collection and testing is part of an ongoing effort to better manage Georgia’s tick population and the diseases the ticks carry. Earlier this year, Emory scientists published detailed, localized maps of where the state’s most common ticks are likely to appear. Now they follow emerging diseases such as Heartlanda still rare virus that causes symptoms such as fever, fatigue, nausea and diarrhea.
Nationwide, vector-borne diseases – that is, diseases spread by vectors such as ticks and mosquitoes – are on the rise, According to the CDCand climate change is a big factor.
Matthew Pearson / WABE / Grist
“Changes in climate lead to changes in the environment, which lead to changes in ecology, incidence and distribution of these diseases,” said Ben Beard, the deputy director of CDC’s Division of Vector-Borne Diseases.
There is a lot at play with vector-borne diseases, not all of which is related to climate change. These diseases live in animal hosts, so scientists must consider how climate change affects those animals as well as the vector species such as ticks. Humans continue to enter forested land full of host animals and ticks, increasing their interactions and potential exposure.
As for the ticks themselves, longer summers and milder winters mean they come out earlier and stay longer. The lone star tick, which carries the Heartland virus and has long been widespread throughout the South and Mid-Atlantic, is expanding north and west as the climate warms. So is the black-legged tick, which transmits Lyme disease expand its range – especially in areas that have seen significant warming, Beard said.
“So all of those things kind of come together,” he said. “And so the net effect is that you potentially have more people over a wider geographic distribution, and over a longer period of time during the season potentially exposed to the bites of infected ticks.”
That’s exactly why the Georgia researchers are trying to better manage ticks and their diseases: so they can help people avoid getting sick.
“My hope is that people in these regions that are predicted to have a high probability will take more preventative measures when they’re out hiking, or just out in the garden, just generally interacting with our environment to hopefully prevent them any tick-borne diseases,” said Steph Bellman, who led Emory’s lone star tick mapping project.
As for the Heartland virus, it’s still largely a mystery, Lewis said.
“There is no treatment at this point other than just taking care of the symptoms,” she said. “It’s considered an emerging pathogen, so pretty rare.”
More than 60 cases in 14 states are at the Centers for Disease Control and Prevention from 2022. It’s still a very small number, but scientists want to be ready in case it grows.
“We’re taking the steps to understand it now, so if an increasing human incidence were to happen, we know what can be done,” said Emory environmental sciences professor Gonzalo Vazquez-Prokopec, who leads this research team.
They are establishing a baseline of knowledge and research, he said, so they can stay on top of these diseases as they move and the climate changes.
