They're here

You could say that Risa Pesapane, PhD, knows what “ticks” when it comes to zoonotic disease. 

On any given day, you might find Pesapane, a disease ecologist, testing mailed-in tick samples for infectious disease; collecting ticks in fields, forests, and farmland; teaching veterinary medical students, veterinary public health students and other graduate students how to identify ticks; or sharing the latest infection data with the Ohio Department of Health.

One thing is for certain: Pesapane is on a mission to reduce the threat of ticks and tick-borne pathogens in humans and animals in Ohio — and her research aims to do that and more.

The ultimate goal? To use research findings to predict health risks to humans and animals and to educate communities about best intervention and prevention practices.

Ticks are getting a foothold

“We have new ticks expanding into the state, and as tick diversity increases, so does the diversity of pathogens we can be exposed to,” says Pesapane.

She says several factors are responsible for the rise in numbers, such as land use changes like reforestation, the increasing deer population (which are frequent hosts), and global trade and travel.

Pesapane’s research on ticks and tick-borne pathogens reveals several significant findings:

• The number of ticks and tick-borne pathogens in Ohio has increased substantially in recent years. In some areas of Ohio, two out of every three blacklegged ticks carry the bacteria that causes Lyme disease, and some are infected with multiple pathogens that can cause illness in people and pets.

• The blacklegged tick (also known as the deer tick) has also expanded across the state and is reported to be in 83 of Ohio’s 88 counties. Over 25,000 ticks from 73 counties have been logged and reported to the Ohio Department of Health since 2019.

• New tick species such as the Asian Longhorned tick (ALHT) — identified in Ohio for the first time in 2020— and the Gulf Coast Tick, which had been periodically reported but now is established here, continue to expand in Ohio, where Pesapane is designated as the state’s ALHT reference and reporting laboratory. The ALHT has now been found in 16 Ohio counties, including Gallia, Belmont, Morgan, Monroe, Guernsey, Jackson, Ross, Franklin, Delaware, Athens, Lawrence, Muskingum, Coshocton, Licking, Washington, and Vinton. Female ALHT can reproduce without mating and lay up to 2,000 eggs.

“These findings are especially concerning in Ohio because we don’t have the social awareness of ticks and tick-borne diseases that states with a longer history of ticks like Connecticut, Massachusetts and New Hampshire have,” she says.

“Our increased exposure increases our risk of developing disease,” she says. “This is happening because the ranges where we typically find these ticks are expanding.”

The implications of infection can be serious, she says, potentially leading to long-term severe illness in people and possible death in animals if undetected.

According to the Centers for Disease Control and Prevention, more than 300,000 people nationally are infected with Lyme disease each year, which is transmitted by the blacklegged tick. Many thousands more infections go unreported. In Ohio, the annual cases of human Lyme disease have increased 16-fold, from 67 in 2012 to 1,079 in 2023.

In the field and the lab

Pesapane’s lab employs several strategies to monitor the abundance and distribution of tick species and tick-borne pathogens in Ohio, including active field work to collect ticks and sometimes the hosts themselves, both wildlife and livestock.

“With field work, we can learn what hosts ticks are feeding on, which can influence the pathogens they may carry and this factors into our evaluation of their potential impact on health,” she says. “We can also evaluate interventions to actively reduce the number of ticks at a site.” 

Pesapane and her team are especially interested in what pathogens ALHT may be carrying since this tick is new, and it’s not yet fully understood how it may impact animal and human health.

Already, there are a growing number of cases of bovine theileriosis in Ohio, which is caused by a pathogen that came to the United States along with the ALHT. Theileriosis can cause increased heart and respiratory rates, anemia, jaundice and mortality.

The Pesapane lab also partners with veterinary clinics, the general public and parks statewide to collect ticks. Anyone can submit ticks to the lab, which then identifies them and conducts pathogen testing to learn what types of bacteria they carry, and reports this data to the Ohio Department of Health Zoonotic Disease Program. The lab team records the information, including site locations, that is included in the data submitted to a federal database. 

The Pesapane Lab, which is affiliated with the Ohio State Department of Veterinary Preventive Medicine, the School of Environment and Natural Resources and other units, works closely with state agencies in Ohio, such as the Department of Health and Department of Agriculture, as well as city and county health agencies and veterinary practices.

Community engagement and One Health

The Pesapane Lab has extensive community outreach efforts, which include creating and distributing education and extension materials to the public, veterinary clinics and livestock producers.

As part of its One Health approach, Pesapane’s team has plans to create an on-demand tick testing service lab for the general public in collaboration with the Ohio State Infectious Diseases Institute.

Lastly, Pesapane is working with students from New Philadelphia High School in Tuscarawas County, where tick abundance is growing. Science teacher Kip Brady, interested in including tick education and testing in the biology curriculum, obtained grants from the Entomological Society of America and the Ohio EPA to fund the project.

“The students learn how to safely collect ticks, bring them to their lab, do DNA extraction and test for the bacteria that causes Lyme disease right there in the classroom,” says Pesapane, who then does parallel comparative testing of the student’s work in her own lab.

“It’s an amazing program,” she says, with students learning about biology and a very serious problem in their county in an exciting way. “They’re also getting STEM exposure and potentially gaining an interest and excitement about vectorborne disease and public health.” The students later teach community members about ticks on community night.

Pesapane says the possibilities for growth in the K-12 space are exciting in terms of community outreach.

“We have professionals who need this training, but it’s better if we can do it earlier in the pipeline if we really want to have an impact.”

The research taking place in the Pesapane lab surrounding tick-borne pathogens exemplifies the innovative and impactful research taking place at Ohio State’s College of Veterinary Medicine to improve the health of animals and people throughout our local community, across Ohio and globally, advancing our ambition to Be The Model® comprehensive College of Veterinary Medicine in the world.