October 07, 2020

They suck blood, they’re hard to find, and there is a small group of people who are absolutely fanatic about them.

No, we’re not talking about vampires. We’re talking about ticks!

Ohio is home to several different species of ticks—and, as tick experts in Ohio are discovering, more are moving in.

While a tick bite won’t turn you into a member of the living dead, ticks are vectors for harmful diseases that can affect humans and animals. A vector, unlike a vampire, is a living organism that carries and transmits an infectious pathogen. Vectoring illnesses such as Lyme disease and Rocky Mountain spotted fever, ticks are a top priority for experts seeking to stop the transfer of disease

Despite their tiny size, detecting these different types of ticks is no small task.

Risa PesapaneThankfully, experts like Dr. Risa Pesapane are on the job. Dr. Pesapane is an assistant professor in the Department of Veterinary Preventive Medicine and the School of Environment and Natural Resources. She is a proud member of that small group of people who are fanatic about ticks. Officially, we call them acarologists—those who study ticks and mites. Rather than vampire hunters, acarologists are more like vampire scientists; they identify ticks and try to understand where ticks are moving, how they survive, and how they transmit disease.

Given the prevalence and variety of ticks that call the state home, Ohio is an ideal laboratory for tick scientists. American dog ticks have long been endemic to the Buckeye state and different species of ticks have been encroaching on Ohio—lone star ticks from the south, and black legged ticks from the east and west.

“We’re basically in a tick sandwich,” says Dr. Pesapane.

Asian longhorned ticksEarlier this summer, Risa detected a new ingredient—she identified the first Asian longhorned tick in Ohio. But this wasn’t just serendipity—Risa has been strategically developing a system for tick surveillance by collaborating with community partners in Ohio.

IDI asked Risa more about her discovery, her surveillance methods, and her love story with an arthropod that ticks most people off.

Not So Hopeless Romantic

Risa didn’t always care for acarology. “I like to say that I had a slow romance with ticks,” she says. According to Risa, there was a time when she thought ticks were gross—so, what lit the spark?

Our love story begins with Risa’s research in wildlife health and disease ecology. Those two areas of study, she says, bleed into One Health. OneHealth is the collaborative efforts of multiple disciplines working locally, nationally, and globally, to attain optimal health for people, animals, and our environment.

While completing her PhD, the study system Risa worked in involved ticks. That’s when the scale of the problem really started to suck her in:

“I was really exposed to how understudied ticks were and how underrepresented acarologists...were in vector-borne disease in the United States. We’ve had a precipitous decline in the training of medical entomologists. At the same time, we’ve had a staggering increase in tick-borne disease over the past 20 years. I began to respect the need for this type of research and love the complexity of the ecology behind tick-borne disease.”

Soon, the bugs that used to get under her skin were regularly under Risa’s microscope. Today, Risa primarily works with ticks and mites. And, of course, the creatures that ticks like to bite.

Puppy Love Leads to Tick Discovery

Risa’s research program is working with the Ohio Department of Health to establish a baseline understanding of what tick species, and tick diseases, we have in what counties within Ohio. In order to develop a baseline, Rise developed three surveillance programs: one with the public, one with deer, and one with dogs.

The third program, a surveillance project in shelter dogs, led to the discovery of the first Asian longhorned tick in Ohio. The project was targeted to the southern part of the state where Ohio has a high diversity of ticks.

Risa was aware that the U.S. Department of Agriculture (USDA) had reported several counties in West Virginia just across the Ohio River that had the Asian longhorned tick—she had to figure out a way to collect ticks from that area. So, she turned to a scientist’s best friend: a colleague!

Risa, unsurprisingly, is connected to some amazing people. Her colleague worked for Gigi’s, a non-profit shelter partner organization that takes in dogs from high needs, high supply areas and provides them with veterinary care and behavioral training and then places them in rehoming facilities in areas of the state with a high demand for dogs. Gigi’s was a perfect partner, because they pull from these high needs counties in the southern part of the state where Risa was hoping to get ticks and blood samples.

Dogs are picked up by local shelters, and shortly thereafter, Gigi’s is contacted to come and pick up the dogs. Immediately upon intake of those dogs, all ticks that can be found are removed, and a blood sample is drawn. Gigi’s collects blood samples until they have a certain number, and Dr. Pesapane typically picks them up every month. Her lab then identifies the ticks and test for tick-borne disease in the ticks and the dogs.

And sure enough, one of the dogs transferred in from Gallia County in May was carrying an Asian longhorned tick. On May 28th, a seven-year-old male beagle was transferred to Gigi’s, and they removed more than a dozen ticks off of him.

To the average person, a tick is just a tick. But not to Risa and her lab—when it comes to ticks, they’re pretty particular. For example, Risa knows the appearance of the Asian longhorned tick down to microscopic detail:

“[Asian longhorned] ticks are small and plain, no ornamentation. They’re brown in color. Generally, you could differentiate them by size or lack of color or patterns. However, it’s really difficult for people to sometimes differentiate ticks once they’ve fed – like an engorged tick. Because they swell, and it makes features very difficult to see. This is why we encourage people to submit ticks for identification.

…[A] fed adult Asian longhorned tick when engorged at its largest size is about the size of a pea...In the laboratory, Asian longhorned ticks have really unique mouth parts. Their mouth parts are triangular in a way that is distinct from most of our ticks in the state. However, we do have one native Haemaphysalis tick that is the rabbit tick, so it requires microscopy to look close enough to determine if you have a rabbit tick or an Asian longhorned tick.”

Tick identification in a high-res microscope

Risa’s lab identified one of the ticks pulled from the beagle as the Asian longhorned tick. It was a nymph stage, so there was no sex, but they immediately recognized that it was an exotic tick Haemaphysalis longicornis which Risa knew had not been reported in Ohio. She had another acarologist confirm the identification and then sent the sample per protocol to the National Veterinary Services Lab (NVSL). When an Asian longhorned tick is found in a new state or even a new county, NVSL must confirm it at the national lab. Soon after, NVSL confirmed Risa’s identification.

Ticking Time Bomb

The presence of the Asian longhorned tick has major consequences for Ohioans, especially folks in the livestock industry.

First, the tick can potentially transmit a disease called theileriosis, which causes illness in cattle. Second, because they reproduce in the absence of a male and the females lay more than 2,000 eggs, Asian longhorned ticks are often found in very large population sizes, creating really heavy infestations on livestock that can cause significant blood loss leading to reduced production. This blood loss can lead to abortion of calves, and it can even lead to death of the animal itself. In North Carolina, cows have died from acute anemia due to Asian longhorned ticks essentially sucking them dry of blood.

To address the issues presented by this new tick, it’s going to take teamwork. Thankfully, at Ohio State and across the state of Ohio, there is no shortage of team players, even when it comes to ticks.

An ad hoc inter-agency team for dealing with ticks has emerged from Ohio State Extension’s engagement with the public and producers. In order to rapidly create education and outreach materials to identify the Asian longhorned tick, the College of Veterinary Medicine, the College of Food, Agriculture, and Environmental Sciences, and Ohio State Extension are partnering with the Ohio Department of Agriculture, the Ohio Department of Health, and the USDA Veterinary Services Ohio.

Ohio State Bites Back

According to Risa, Ohio State is in a position to lead tick-borne disease research for the state of Ohio.

Ohio State is home to an ensemble cast of bug-loving superstar experts. There’s the Biting Insect Team Education (BITE) team, which includes people who research vector-borne disease in general like mosquitos from OSU’s entomology department. There are nationally-recognized experts in ticks and mechanisms of vector transmission like Dr. Yasuko Rikihisa and Dr. Hans Klompen. There’s Risa, who is a disease ecologist focusing on ticks that spans veterinary and public health needs and now agricultural needs. And, there are folks from the Extension education team that have been doing tick education for a long time, like Tim McDermott.

That’s just the start—Risa is part of the “Ohio Regional Tick Symposium Planning Committee” which is planning Ohio’s first tick conference. The state has never had a conference dedicated to discussing ticks and tick-borne disease, but Risa is ensuring the Buckeye state ticks that one off.

Many Factors, One Health

The Pesapane lab will be leading the identification of suspected Asian longhorned ticks in the state. Materials went out in early September that included information on how people can submit any suspicious tick on their farm or on their animals to Risa’s lab. The Pesapane lab is now actively accepting ticks. This will directly contribute to Risa’s original goal of wanting to know what ticks we have and where we have them in the state.

“From a research standpoint, this is a wonderful opportunity to gather large amounts of information from the public on where we have different species of ticks occurring in the state,” says Risa. “And that is the baseline information we would need to ask bigger questions about the ecology of Asian longhorned ticks in the state. We still know very little about the ecology of Asian longhorned ticks in the United States, since this is a novel habitat.”

Though the Asian longhorned tick poses the biggest risk to cattle, the tick is most commonly found on deer and dogs in the United States.

Risa Pesapane dragging for ticks

“This study is a beautiful example of why, if we’re interested in livestock health, we need to be partnering with our veterinarians and partnering with our wildlife folks, because we are perhaps more likely to see this tick first in those populations,” says Dr. Pesapane. “I think it’s a great example of how you need to do One Health surveillance across these different animal disciplines to appropriately detect this tick, because it’s been reported on more than two dozen species, and most of those species are wildlife species.”

Public Tick Talk

Risa has spread her passion and for One Health surveillance—and ticks—through two other surveillance studies are also based in partnerships with the public, and public services.

In April of 2020, Risa started a public tick submission program. It started small—she started by asking hunters and trappers to submit ticks that they might pull off of animals as they were out doing their hunting activities. Then, it got larger—she worked with the Ohio Department of Natural Resources and the Ohio State Trappers Association, and asked them to send in any ticks that they were encountering or pulling off of wildlife. And larger—those folks forwarded onto foresters, and they forwarded on through Facebook to outdoorsmen groups. And larger—Risa did an outdoor radio interview for The Big Outdoors radio.

With the call for ticks spread across the airwaves, Risa’s tick submission is still growing. Since April, she’s had over 744 ticks submitted from the public all over the state. And, Risa makes sure the public always sees the benefit of their participation—the data from the surveillance is shared directly with the Ohio Department of Health, so that her lab’s research feeds directly into the needs of public health.

Critical Tick Takeaway

Risa doesn’t want you to get the wrong impression about the risk the Asian longhorned tick poses to you or your furry friends.

Just because we have no known human or domestic animal disease doesn’t mean we won’t. In the laboratory with ticks from the U.S. population, scientists have learned ticks are capable of transmitting at least the bacteria responsible for Rocky Mountain spotted fever, so there’s a concern that it’s only a matter of time before Asian longhorned ticks are transmitting more than livestock disease.

“All tick bites should be taken seriously,” says Risa. “People should take preventive measures like wearing repellant and appropriate clothing to prevent tick bites, and they should save the tick for identification and be noting on a calendar any time they’re bitten by a tick so they have that information for their doctor.”


Dr. Risa Pesapane is an assistant professor in the Department of Veterinary Preventive Medicine and the School of Environment and Natural Resources.


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