Research Publications

Featured Principal Investigator: SFWS Research to Study Prevalence of Tick-Borne Diseases in Alabama

As most people who spend time in the outdoors know, exposure to ticks is all too common in the South. What is less known by the medical community and the public, is the degree of risk associated with these encounters.

There are several tick-borne illnesses that can be transmitted by ticks to humans and pets in the Southeast, including Rocky Mountain spotted fever, Lyme disease, ehrlichiosis, and others. Lyme disease is the most commonly reported vector-borne disease in the United States and is caused by bacteria that is carried and transmitted by black-legged ticks. Although Lyme disease is widely thought to be a problem of the Northeast, it has been established by experts in the fields of vector-borne disease ecology and epidemiology that the disease has also presented signs and symptoms in human patients in the South, consistent with Lyme disease recognized in the northeastern parts of the country. People and pets have been infected with Lyme and other tick-borne illnesses in all US states, including those in the Southeast, and every year tens of thousands of new cases emerge across the nation. According to the Alabama Department of Public Health website, there have been 48 confirmed cases of Lyme disease in Alabama within the last 12 months.

Emily Merritt, recent graduate of the School of Forestry and Wildlife Sciences and Research Associate, grew up in New York, a tick infested part of the country, and is well familiar with the realities of tick-borne illness. States Merritt, “When I moved to Alabama to pursue a master's degree at Auburn University, I realized that there was a problem with ticks and tick-borne illnesses here; but no one really talked or knew about it.” As she began researching the topic more, she found that doctors often misdiagnose and mistreat patients who have tick-borne illnesses because the medical community and the general public are not aware of the scope of the issue in the state.

Recognizing a gap in research about the distribution of ticks and prevalence of tick-borne diseases in Alabama, Merritt approached Dr. Graeme Lockaby, Associate Dean of Research of the School of Forestry and Wildlife Sciences, about the potential to undertake a study focused on the issue with the goal of identifying tick habitats and the degree in which ticks carry disease.

According to Dr. Lockaby, “While we in the SFWS are not trained medically, we are highly qualified to create precise descriptions of vegetation, stream, soil, and topographical habitats as well as to assess climate variation. With this expertise, we hope to clarify which habitats different species of ticks occupy and what climatic conditions contribute to the distribution and prevalence of ticks and tick-borne diseases in Alabama. This information will then be used to develop a risk prediction tool that will help us better educate Alabama residents, medical professionals, state and federal agencies, and others on the areas of greatest risk and what they can do to avoid tick contact.”

Realizing, by its nature, environmental health is complex, it was understood the project would require an interdisciplinary approach. With the addition of Rajesh Sawant and Dr. Sarah Zohdy of the SFWS, Dr. Derrick Mathias of Auburn’s Department of Entomology and Plant Pathology, and Dr. Navideh Noori of the School of Ecology at UGA; the research team unites expertise in wildlife science (particularly host interactions), forest ecology, climate modeling, DNA analyses, remote sensing and spatial analyses, and potentially in the future, sociology, to reach its primary goal of predicting risk. 

Dr. Mathias, whose role will be to identify the ticks collected by morphology and screen them for pathogens using molecular methods, states of his involvement, “I became interested in working with this team due to their expertise in ecological modeling, forestry, and wildlife biology. Tick-borne pathogens are zoonotic, meaning that they cycle among wildlife, and therefore, humans are incidental or “dead end” hosts. Zoonoses are very complex systems, so it takes a team of people with a diverse set of skills to determine why we see the patterns of disease that we do.”

Based on data from the Alabama Department of Public Health, we know clinical cases of tick-borne diseases in the state vary substantially between counties and that the number of cases has gone up significantly over the last several years. Mathias further explains, “These data provide clues about areas in the state where ticks thrive, but what we don’t understand are the factors responsible for variation in disease risk within these hot spots.”

It is this variation that makes the team’s expertise and research approach significant due to the strong correlation between risk and habitat features such as vegetation, topography, and variations in climate that strongly affect arthropods, a group that includes ticks, insects, and spiders. According to Lockaby, “Although this type of work is a new endeavor for the SFWS, it is highly appropriate given the strong linkages between forest fragmentation and arthropod disease vectors.” 

Initial conversations with medical professionals and early research funding from the Alabama Department of Conservation and Natural Resources and the U.S. Forest Service suggests there is strong support for tick-borne disease research in the state. With additional funding the team anticipates their research coverage will grow to encompass a larger geographic area to yield a wider range of applicability of the risk prediction tools and additional disease screening of tick samples. “Ultimately,” states Merritt, “we hope these tools have the potential to enable people to avoid tick encounters and consequently reduce the incidence of tick borne diseases in the Southeast.”