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Biology researchers study deer ticks and the bacteria that cause Lyme disease

Dr. Lloyd Turtinen, professor of biology at the University of Wisconsin-Eau Claire, turned one encounter with a tick into a five-year faculty-student research project that examined the prevalence of Borrelia burgdorferi (the causative bacterial agent and insect vector of Lyme disease) in Ixodes scapularis (the deer tick).

The research findings follow a recent report from the U.S. Centers for Disease Control and Prevention that said the prevalence of Lyme disease in humans is roughly 10 times higher than the number of cases reported nationally each year.

Student researchers Alyssa Kruger, a senior biochemistry/molecular biology major from Oakdale, Minn., and Madeleine Hacker, a 2013 microbiology graduate from Brown Deer, collaborated with Turtinen on the project, which was funded by the UW-Eau Claire Office of Research and Sponsored Programs.

The researchers conducted a DNA analysis on 341 adult female deer ticks collected from 21 counties in Wisconsin during 2010-13, with results showing an average of 35 percent of the ticks testing positive for the Borrelia burgdorferi bacteria. The counties with the highest infected tick prevalence rates were Chippewa (66.7 percent), Dunn (44.4 percent) and Eau Claire (36.5 percent) counties.

Additionally, the results showed the prevalence of positive ticks significantly increased each year of the study. In 2010, the prevalence from all counties was 21.6 percent, which increased to 32.4 percent in 2011, 40.9 percent in 2012 and 51.2 percent in 2013.

For Turtinen, the study began five years ago at the Minnesota State Fair when he noticed a tick burrowed in his leg. The tick was so embedded that he had to go to the health tent to have it removed.

"I was a little concerned about getting Lyme disease from the tick, so I brought it back to a clinic in Eau Claire," Turtinen said. "They told me they couldn't give an antibiotic for Lyme disease until a rash is present. Well, that concerned me because only 75 percent of people who get a tick that transmits the Borrelia burgdorferi bacteria actually get a rash. So there are 25 percent of people who will never get a rash, but still have Lyme disease. I thought it would be nice to know if the tick had the bacteria, so I went back to the lab and started working on a process to detect the bacteria's presence."

Turtinen developed a chemical process to extract all of the DNA from a deer tick, including any bacterial DNA it may be carrying.

"The assay that we used is called real-time polymerase chain reaction," Turtinen said. "In the sample of DNA, designed primers only bind to the specific DNA that causes Lyme disease. When they bind to that, we can amplify a small region of that bacterial DNA. We conduct this analysis in an instrument that actually lets us see the DNA being made in real time. We can see that it's increasing in amount, or amplifying, so at the end of approximately two and a half hours, we basically know whether or not this tick carried the Borrelia burgdorferi bacteria."

Kruger said she found the research project interesting because Lyme disease can affect anyone.

"You can be walking in the park and get a tick on you and potentially contract Lyme disease," Kruger said. "This project is very applicable to everyone, and it's really important to know that Lyme disease is prevalent in the area."

The ticks used for the research were collected by students in Turtinen's infectious disease ecology classes, who went into the field and used flannel material to sweep the ticks from grass and bushes.

Turtinen said he was surprised by the number of ticks that carried the Lyme disease-causing bacteria.

"When we first started this, I didn't think it was going to be in the 30 percent range, but that's what our results show," Turtinen said. "It certainly calls attention to the fact that there are a lot of positive ticks out there and you have to be careful."

Kruger said the most interesting part of the project was compiling the data and seeing the results of their work.

"It was so interesting to see the high levels of ticks that tested positive and how the prevalence of infected ticks was different from county to county," Kruger said. "Dunn and Chippewa counties had higher percentages of positive ticks than Eau Claire County. I thought that was interesting because we're neighboring counties."

Hacker agreed that the differences between counties was surprising and said the sheer number of ticks they analyzed was the most challenging aspect of the project.

"We analyzed 341 ticks," Hacker said. "That's a lot of ticks. We started doing six at a time and then bumped it up to 12 because it wasn't going fast enough. Just putting in that time and effort was the most challenging, but we got there and that was the exciting part."

Turtinen and his research team submitted their study to Emerging Infectious Diseases, a peer-reviewed medical journal published by the CDC.

Because multiple factors could be contributing to the increasing incidence of Lyme disease in humans, Turtinen expects scientists will conduct many more studies on the topic.

"Is it related to the deer population or climate change?" Turtinen said. "There are a lot of factors that affect the number of infected deer ticks, so I think you're going be seeing a lot of ecological studies looking at those factors and the increase in Lyme disease."

Being a part of a research project that has the potential to impact the public was rewarding and provided a hands-on practical application of all the laboratory methods and procedures she previously learned in the classroom, Hacker said.

"I never would have known what it would be like to conduct research had I not been a part of this project," Hacker said. "I think it's really important for students to make the most of the faculty-student collaborative research opportunities UW-Eau Claire provides. Forming a close relationship with your professor is an advantage this school offers over larger universities. It's a great opportunity to have this experience as an undergraduate."

Kruger said conducting the research project with Turtinen solidified her desire to go into research and apply for graduate school.

"Every biology class teaches you about techniques and procedures, but it's hard to grasp the concept of how they all work together until you're actually doing it yourself," Kruger said. "Being hands-on with a project helps it all click together and make so much more sense. I'm interested in the field of genetics and human diseases and am hoping to get into a Ph.D. program in either molecular biology or human genetics. I feel really prepared to enter into research at a graduate level now that I have had this experience with Dr. Turtinen."

Turtinen said he enjoys working with undergraduate students and seeing them come to appreciate the entire research process.

"One of the things I really want them to see and learn is that sometimes things don't work," Turtinen said. "Sometimes there's failure and then you have to figure out why it didn't work. So, with all of my students, we have gone through periods where things aren't working and they have to figure out what the problem is."

For more information about the research project on deer ticks and the bacteria that cause Lyme disease, contact Dr. Lloyd Turtinen at or 715-836-3506.