Tick-Talk with researcher Robert Colautti

Tick-Talk with researcher Robert Colautti

The evolutionary biologist discusses ticks, tick-borne diseases, and his part in developing a portable device to test ticks for Lyme disease while in the field.

August 16, 2021


Deer tick closeup
Closeup of female deer tick underside, showing the barbed, needle-like hypostome (i.e. mouth) and palp (i.e. mouth cover). (Courtesy of Colautti Lab)

In the past two decades, tick-borne diseases like Lyme disease have increased in Canada. Queen’s professor Robert Colautti and a team of researchers are developing a portable device that will get purified DNA/RNA from ticks on site. Instead of waiting for results from a lab, this device can be used in the field to quickly determine if the tick carries pathogens that cause Lyme disease. The Gazette recently spoke to Dr. Colautti about the device and the myLyme project, which brings together a multidisciplinary team of scientists to tackle the problem of tick-borne diseases in Canada.

Research demonstrates that deer ticks are more abundant in Ontario than 10-20 years ago. Can you give us some insight into why this is?

The main tick that transmits Lyme disease is the deer tick (Ixodes scapularis) and it has definitely increased in abundance and expanded its range northward into Canada over the last 20 years or so. We also see in Canada a rapid increase in Lyme disease cases over the same timeframe. The ecology of ticks is key to understanding why.

Deer ticks live for two years and require only three blood meals during this time. Many pathogens like Borrelia are not transmitted through the eggs so the number and types of pathogens depend on what the tick is feeding on. Different hosts species (e.g. mice, racoons, deer) are fed on by different life stages and each species can carry different pathogens in their microbiome. Human impacts on climate and habitat can directly impact the survival of ticks but more importantly they impact the host populations, and this can create some complicated dynamics in the number of ticks and the health risks they pose each season.

Lyme disease is caused by a group of bacteria carried by deer ticks called Borrelia burgdorferi, but it’s important to know that there are other emerging diseases in Canada caused by other pathogens carried by deer ticks. These include other bacteria that cause Anaplasmosis and a Lyme-like relapsing fever, as well as a malaria-like parasite that causes Babesiosis, and the Powassan virus, which is a flavivirus related to the viruses that cause Zika, West Nile and dengue.

How should people adapt to this new reality of living with a greater amount of deer ticks?

At an individual level, prevention is a very effective and relatively simple strategy. Deer ticks live in wooded areas in leaves and brush, so whenever I am out in the deep woods, I wear long pants tucked into my socks, which I spray with a strong repellent. A common misconception is that ticks are insects, but they are actually arachnids like spiders, mites and scorpions, so not all insect repellents will be effective against ticks. It’s important to read the label carefully. Ticks tend to grab on to you when you brush against leaves or sticks near the ground and then slowly crawl up your body, so I spray my clothes and shoes from the waist down and this is usually enough to deter them. In conservation areas, I stay on the main trail and avoiding going off into heavier leaf or brush where ticks might be waiting. Pets are another source of ticks, and even though there is a vaccine for dogs, they can still bring ticks into the house. After returning from the deep woods or a day in the field I will shower, wash my clothes, and check for embedded ticks as soon as I get home.

At the public health level, there is also a lot we need to do in terms of monitoring natural populations, educating health practitioners, improving diagnostic tools, and understanding complex symptoms and treatments of tick-borne diseases.

Can you tell us about your work into developing a portable device to test for Lyme disease? How would it work?

The device is still in the development stage. It is being developed with Indumathi Prakash, an intern from Harvard University funded by a scholarship from the Mitacs GlobaLink program. Our device is designed to get DNA and RNA out of ticks and then purify and stabilize the DNA/RNA for analysis.

Usually, we would bring the tick back into the lab, sterilize it, freeze it to -80 C, grind it up in a machine, and then begin a long process of lysing the bacterial cells and purifying the DNA/RNA. Once we have the DNA we can use other tools in the lab to amplify specific genes and then sequence them. From the DNA and RNA sequences we can reconstruct the entire microbiome of the ticks as well as the genes of the tick itself. Analyzing tick genomes and microbiomes lets us probe the ecological factors that affect the spread of ticks and the microbes they are carrying.

The key innovation for this project is that we are trying to do the whole lab extraction process in a small device in the field. Getting purified DNA/RNA from these ticks is the key step that would enable field-based sequencing and rapid tests for specific tick-borne diseases. But this requires another device or two.

If someone finds themselves bitten by a tick, what should they do?

The simple and best answer is to talk to your doctor. If a tick is embedded, then it’s important to try to remove it with tweezers by the head to avoid breaking it open. You can kill it in your freezer and then bring it to the doctor who can request for testing from Public Health Ontario. You can try to assess how long it has been feeding, which is important because the risk of disease increases with feeding time, which can last three to four days for nymphs and seven to 10 days for adults. You might be able to figure out feeding time based on your activity, for example if you just got back from a three-hour hike in the woods then you know it hasn’t been feeding more than three hours. You can also look at the tick. If the body is still flat, then it hasn’t been feeding long. If it is expanded like a tiny balloon, then it may have been feeding for a while and you should see your doctor as soon as possible.

Can you tell us about myLyme project?

The myLyme project is funded by a Wicked Ideas grant from Queen’s and an Exploration grant from the New Frontiers Research Fund. These grants support a new approach to science called “convergence research” or “transdisciplinary research.” Convergence research combines expertise from broadly different areas to tackle difficult problems in a way that can’t be done through more conventional approaches. The myLyme project brings together health scientists, social scientists, and natural scientists to tackle the problem of tick-borne diseases in Canada. We think tick-borne diseases represent a wicked problem because health impacts depend on the complex ecology and genetics of ticks and the microbes they carry, but symptoms also depend on human genetics and behavior, and treatments by healthcare practitioners who vary in their knowledge of this emerging healthcare threat.

Tell us about the myLyme project 2020 survey and the current 2021 survey?

The 2020 survey was developed by Emilie Norris-Roozmon who is co-supervised by Rylan Egan (Health Science) and myself. That survey has ended, and Emilie is currently writing up her Master's thesis based on the results. More than 1,200 anonymous respondents reported being bitten by a tick with symptoms ranging from none to multiple, long-term chronic effects. We were expecting 100 to 200 for this kind of study, so the large number shows us how many people care about this issue. Emilie’s focus is to see how well the self-reported symptoms can predict their reported diagnoses. We are also trying to see whether there is evidence for syndromes or clusters of symptoms that might indicate different diseases in the cohort.

The 2021 survey is the work of Tim Salomons (Psychology) and Nader Ghasemlou (Health Science), who both study chronic pain and cognition. It is open to anyone who self-identifies as suffering from a tick-borne disease — regardless of diagnosis — and it includes a general online survey followed by an optional follow-up survey that uses a smartphone app to help patients track their symptoms over time.

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