Researchers from the University of Minnesota College of Veterinary Medicine are taking what they learned at Itasca State Park last summer studying Lyme disease in ticks to show how mobile labs can be a useful tool for researchers around the world.
Peter Larsen, an assistant professor and molecular biologist in the Department of Veterinary and Biomedical Sciences, was accompanied by research scientists Kenwyn Shriner, a second-year Department of Veterinary Medicine/Minnesota Public Health student, and Laramie Lindsey, a postdoctoral scholar.
“The deployable mobile lab can fit into two suitcases and it has everything we need to screen for pathogens,” Larsen said. “We wanted to show it was possible to generate results in less than 12 hours. We were able to look at DNA extracted from ticks to see if they had the causative agent for Lyme disease within a couple of hours of collecting the ticks, with 25 to 30 percent carrying Lyme. The next step is sequencing the DNA of the causative agent of Lyme disease, the Borrelia bacteria, and that can typically take days if you send your sample into a traditional lab for sequencing. We showed that we can do that in less than a day with the mobile lab.”
Larsen said that to extract the DNA, “basically, you take the tick and liquify it, then you use a combination of different detergents and chemicals to extract all the DNA from that tick and that includes any DNA from tick-borne pathogens.”
Larsen said detection is the first step in dealing with a disease like Lyme.
“We can expand this mobile testing to parks and recreation areas and sample ticks there, and rapidly say what the density is of those tick-borne diseases. Then strategies can be put into place and information shared with public health officials.”
He said it is important to understand strain variations of the causative agent of Lyme disease.
“The more data you generate like that, the more you can understand how that pathogen is moved from location to location and how it has evolved through time. That information can ultimately be used to form treatment strategies. There are researchers all around the country working on vaccines for tick-borne diseases and treatment options. The data we generate, describing what is out there, can help inform other research teams who are working on developing therapeutics.”
Wood ticks of Itasca
Researchers tucked their socks into their pants, zipped up their painter’s suit and fashioned drag clothes to pull through the woods to collect ticks. They purposefully did not apply insect repellent, as ticks won’t approach with any present.
Larsen said dragging a burlap cloth through woods is a standard method for sampling ticks. “It’s something ticks can hook onto,” he said. “Ticks like to congregate on the tips of grass or other vegetation along trails where deer and other wildlife walk. When we are out hiking on wilderness trails we can also pick up ticks.The ticks respond to the dragging cloth like they would to a passing animal or person and hang on.”
After an hour and a half, researchers had collected 39 adult ticks.
“I was shocked by the amount of ticks we found in our first location on this trip,” said Shriner, who later spent another hour and a half in other parts of the park rounding out her sample to a total of 50 ticks. “It was almost a little scary. On previous trips I have been on, I have collected 40 adult ticks after a full eight-hour day.”
Larsen said many factors influence tick density across the state.
“Certain areas may have high or low tick density,” he said. “The environment at Itasca is probably similar to the rest of northern Minnesota.Ticks like leaf litter, but there are other environmental characteristics that affect the tick population, too, like whether it has been a wet or dry year.”
Larsen said the white-footed mouse and deer mouse in the state are a reservoir for Lyme disease. “The mouse can carry Borrelia, and when a young nymph tick feeds on the mouse it can pick up the disease. Eventually, the adult tick can transmit that to humans. It is all one process.”
According to information from Dr. Oliver, an assistant professor in the University of Minnesota School of Public Health and public health entomologist, there are approximately 1,000 to 1,400 cases of Lyme disease per year, but this number likely underrepresents the actual number of cases.
Nationwide, about 33,000 cases per year fit the Centers for Disease Control and Prevention definition of Lyme disease, though the agency admits there are probably actually around 300,000 cases per year.
While Lyme disease is the most prevalent tick-borne disease impacting people, there are many more out there, including human granulocytic anaplasmosis, ehrlichiosis, tularemia, Rocky Mountain spotted fever and other spotted fevers, tick-borne relapsing fever, q-fever, Colorado tick fever, Powassan virus, Bourbon virus, Heartland virus, Southern tick-associated rash illness, and babesiosis.
Benefits of mobile testing lab
“The mobile labs can run on battery packs,” Larsen said. “Our three-week trip to Borneo in August showed we can go anywhere in the world to do research using these labs. Once mobile labs like this become more accessible, there could be one set up on site at Itasca or anywhere in the world, so researchers can do screenings themselves with a few days of training. You don’t need a big brick-and-mortar lab.”
The Borneo trip was funded by the University of Minnesota’s Center for Global Health and Food Studies, where work was done through a collaboration with the University of Malaysia Sarawak.
“We trained 10 students and one faculty member from the university in how to use the mobile lab,” he said. “Then we set them up with their own mobile lab they can use to look for emerging diseases.”
Out in the field, members of the group looked for food-borne pathogens circulating in wildlife, such as salmonella and E. coli. “The biggest thing we found was evidence of listeria, an emerging pathogen of concern, in rodents at a picnic area. Listeria outbreaks can kill people.”
The goal is to use what is learned through research to understand how diseases are spread and stop that from happening.
“We want to leverage these emerging tools and advance rapid diagnostics to help detect disease,” he said. “We want to do everything we can to speed up the diagnosis. That’s the first step. Then the medical community can take action.”
One world, one health
Larsen said the relationship among humans, domesticated animals and wildlife is referred to as “One Health.” That relationship is complex and understanding those interactions is essential to understanding the health of all species on earth.
“Many diseases have adapted to spread across this web of animals and humans, infecting our food supply, harming endangered species, and potentially even leading to future pandemics,” he said.
“What our lab is trying to do is discover emerging pathogens and diseases all around the world that are coming from wildlife or insects. The focus is understanding the interface between wildlife and agriculture and humans. What diseases are circulating throughout that triangle? This lies at the heart of our research program.”
Larsen said climate change is absolutely influencing the distribution of wildlife and pathogens. “We see wildlife moving in the U.S. and the associated pathogens that may be linking in those animals and insects are part of this broader issue. We see certain pathogens expanding their distribution that way. Being aware of how dynamic that process is emphasizes the importance of surveillance. That is why public health departments have these projects to try to understand how things move and if new pathogens start coming on the scene. Biosurveillance is so important, to track how tick-borne pathogens are moving and changing.”
The next trip Larsen is planning is to Guyana, in the northern Amazon region of South America, with a return trip to Borneo on the agenda for next summer.
“We’re also going to be visiting farms around the state with these mobile labs,” he said.