GREENSBORO, N.C. (WGHP) — In the wilds of North Carolina, ticks and other creatures are known to spread certain diseases, but how can we control those diseases at the source without damaging the environment?
Researchers working with the University of North Carolina at Greensboro are answering that question by going out into nature and getting a firsthand look at how diseases develop.
Ecological approach
The “medical approach” would have each patient treated one at a time when they get sick. The “ecological approach,” on the other hand, focuses on the source of the sickness in the wild.
“People just used the medical approach … end-of-the-line … whack-a-mole type of approach where you just take each case at a time and try to fix it,” said Dr. Gideon Wasserberg. “But they haven’t used the upstream approach that the ecological approach takes … to understand what is happening at the source. Once we understand … what happens at the source … you can make predictions as to where and when those diseases could occur and where people might come in contact.”
Wasserberg, a professor at UNCG in the Department of Biology, is an infectious disease ecologist.
“The general motto of my research is the application of an ecological approach to the study of infectious diseases that are associated with … wildlife components,” Wasserberg said.
He works alongside a group of researchers to observe and model how infectious diseases develop through a complex interaction between the carrier of the disease, the host and the environment where they both live.
One benefit of this research is that it helps scientists learn how to spot the development, severity and evolution of a disease in nature and find any weak links.
“This type of ecological understanding might shed light on potential weak links in the transmission cycle that could provide opportunities for novel, effective, targeted and environmentally-friendly approaches for control of the disease or at least prevention or reducing the exposure,” Wasserberg said.
Studying tick-borne diseases in NC with the ecological approach
Wasserberg and other infectious disease experts with North Carolina universities have been doing active surveillance for black-legged ticks in state parks across several North Carolina counties.
“The tick story is relatively newer. We started working on that system in 2017,” Wasserberg said. “There appeared to have been a trend of increasing incidence of Lyme disease in North Carolina, but there was barely any data on the tick distribution.”
“We sampled on a north-to-south gradient going from the border with Virginia, going down to Greensboro … Later on, we expanded towards the northwest area: Ashe, Alleghany, Watauga. … That area had the highest rate of human case reports.”
The study is currently expanding to central North Carolina and the coastal region.
“The main finding was there was a strong consistency of the abundance of ticks with human cases … in Ashe, Alleghany, Watauga. That seems to be an active hotspot of human Lyme disease as well as tick abundance as well as infection rates in the ticks. … It’s pretty endemic in those areas,” Wasserberg said.
He and other researchers used the ecological approach to determine if that area’s natural settings, including the mountains and foothills, were potentially suitable areas for Lyme disease to spread.
He said there are three main factors to studying tick-borne diseases that are important for researchers to understand in order to help prevent diseases in nature from spreading beyond hotspots:
- Can ticks survive in a specific environment?
- Do they have the right host?
- Has a seasonal cycle developed?
So what do these three factors look like in a real-world setting?
Wasserberg explained that over a two-year span, researchers trapped rodents and found white-footed mice in North Carolina were “highly competent” hosts because they could effectively carry pathogens and create a cycle.
Researchers also studied the seasonal patterns of the ticks because both the carriers of diseases (ticks) and hosts (white-footed mice) have to work together for a pathogen to spread.
The ticks studied have a two-year life cycle. They are born in the summer and pick up the pathogen around the summer and fall seasons. They, then, go dormant and go into the nymph stage in spring.
“That is crucial on several levels … First, the spring and the winter, people are starting to go out and go explore the outdoors, and that’s exactly when … the hungry, infected nymphs are coming out, so that’s a perfect situation for risk for humans,” Wasserberg said.
This is also the time baby rodents are being born. Diseases can be passed on to them by infected nymphs, so the cycle of infection continues in nature.
One-health approach
The ecological approach is also related to the one-health approach, which is a newer paradigm that Wasserberg says is gaining more traction both in the medical and veterinary fields.
Broadly speaking, the one-health approach is the idea that human health is “tightly interconnected with the health of the natural environment.”
“When you mess with the natural ecosystem, you impact human health, you impact the health of agricultural systems that we all depend on, either animals or plants,” Wasserberg said.
Wasserberg studied La Crosse encephalitis, a potentially deadly virus that inflames the brain. It is the most prevalent mosquito-borne disease in North Carolina.
Within North Carolina, La Crosse encephalitis is most commonly found in neglected areas in the mountains, in rural communities, in indigenous communities and in isolated communities.
“It doesn’t get the attention it needs to,” Wasserberg said. “In collaboration with Prof. Brian Byrd from Western Carolina University, we conducted a study … that evaluated anthropogenic changes to the environment enhances the risk to humans … Often, the environment of housing in that area produces more suitable habitats for the mosquitoes to breed and increases their abundance … their longevity, their size, their quantity, so it’s both quality and quantity that results in higher risk to local people.”
