On March 28, Allison Gardner, an assistant professor in the school of biology and ecology at the University of Maine, led the next segment of the Sustainability Series. This week the talk was called, “The Maine Forest Tick Survey: Cross-disciplinary and community-engaged science for public health” and discussed how the management of forests could lead to a higher risk of exposure to tick-borne disease. Moreover, the high usage of forested land in Maine creates a socio-ecological need to investigate how forest management affects disease transmission.
“We know that global travel and trade, for instance, have facilitated the movement of disease vectors and pathogens. They transmit to new locations over the past few decades. We also see that a combination of land use, change and climate change have facilitated the establishment of these factors and pathogens within their introduced ranges over-reliance on conventional insecticides, has facilitated the evolution of insecticide resistance,” Gardner said. “One of our major goals is to actually translate our findings to devise effective and sustainable disease control strategies that are, you know, ideally grounded in an ecological theory.”
Gardner explained the increase in cases over the course of the past five years, which she has been tracking.
“We’re up to about 43,000 reported cases per year by 2017, and I do want to emphasize that this is likely a ten-fold underestimate of the true number of cases that occurred in the U.S. during this time. We also see this dramatic increase in the number of cases in two particular focal areas of Tick-borne disease transmission, one of them here in the Northeast and the other in the upper Midwest,” Gardner said regarding the transmission of tick-borne diseases.
Gardner elaborated on the scientific research themes and goals for the study. The first of these is to investigate the interacting ecological and social conditions that enhance arthropod-borne disease transmission. Next they would like to explain and predict the spread of emerging and re-emerging arthropod-borne infectious diseases in the landscape. Lastly they want to be able to translate their findings to devise effective, sustainable disease control strategies that are grounded in ecological theory.
“I really want to emphasize that other pathogens like human babesiosis, human granules, cystic, anaplasmosis and poison virus also are emerging and are transmitted by the black-legged tick,” Gardner explained. “Even if we had, for instance, a lyme disease vaccine, which we currently don’t have, there are numerous other pathogens that the black-legged tick is carrying as well.”
Gardner stressed that ecologically-based management could broadly offer solutions to multiple pathogens simultaneously. By using this strategy, pathogens themselves may be mitigated, or at least, their interactions with host bodies.
In 2018, Gardner, Jessica Leahy, Carly Sponarski and Laura Kenefic established the Maine Forest Tick Survey, which aimed to help pinpoint the specific forest management practices that restrict the transmission of tick-borne diseases, as well as management tactics that work with the economic interests of landowners while practicing conservation tactics by preserving biodiversity and helping the ecosystem.
“Incidence is highest in southern and coastal Maine. Over 80% of the forest land actually is privately owned by small family forest landowners that own, in all likelihood, somewhere between five and maybe 10,000 acres,” Gardner said. “It’s really critical to understand how these landowners’ decisions impact transmission, and whether certain management decisions could potentially help to mitigate the problem of lyme disease transmission in Maine.”
This cross-disciplinary study focused on natural science by working with the Maine Woodland Owners Land Trust to understand the impacts of silviculture treatments on entomological risk of exposure to tick-borne pathogens, off-host tick survival, wildlife communities, small mammal behavior, entomological risk of exposure to tick-borne pathogens and tick encounter frequencies. The study investigated social science by looking at the factors that manage decisions by landowners and if this increased knowledge of Lyme disease and the environment context would help motivate the private landowners to be a part of the healthy practices to sustain the entire forest ecosystem.
“Social science elements of this project were designed to measure exactly this. Can exposure to tick-borne disease alter landowner perceptions around forest management and around tick-borne disease potentially affecting landowner decision-making and feeding back on transmission of tick-borne pathogens in the biophysical system?” Gardner said.