Understanding Lyme disease, in real time

Studying how tick-borne bacteria behave in the bloodstream

August 4, 2015

Canada is grappling with a new health threat – a pest that's crashing our camping trips and hiding out in our gardens.

The blacklegged ticks that carry Borrelia burgdorferi (or B. burgdorferi), the type of bacteria that causes Lyme disease, are expanding their territory, putting more people at risk of contracting the disease. In fact, public health researchers have estimated that by 2020, 80% of the population in eastern Canada will live in affected areas, up from just 18% in 2010.

But there are many unanswered questions about B. burgdorferi, and how it actually makes people sick. To help answer some of these questions, Dr. Tara Moriarty at the University of Toronto is studying how this pathogen disseminates – spreads – in the body.

"The most serious consequences of many bacterial infections happen when bacteria enter the bloodstream and spread to other parts of the body," says Dr. Moriarty.

Figuring out the mechanics of how bacteria spread would be an important step toward developing better treatments for Lyme disease and other types of infections. But, until recently, one of the major obstacles to understanding dissemination has been our limited ability to watch how bacteria behave in the bloodstream.

While working together at the University of Calgary, Dr. Moriarty and her colleague Dr. Ursula Norman developed a technique for watching the bacteria in action. Called intravital microscopy, it allows researchers to capture videos of pathogens as they are carried along by the blood.

"We generally work with fluorescent Borrelia, so we can watch them as they're flowing through the bloodstream, or as they are leaving the bloodstream, or study the way they are behaving in the skin, liver, joints or other places," says Dr. Moriarty.

Funded in part by the Canadian Institutes of Health Research, Dr. Moriarty has used this innovative technique to uncover how the bacteria stick to the cells lining the inside the blood vessels, so that they can slow down and enter tissues, spreading infection in the body. Previous researchers studied how the bacteria do this in blood that isn't moving, but Dr. Moriarty and her team have shown that B. burgdorferi relies on completely different mechanisms when they are in a flowing bloodstream.

As Dr. Moriarty's lab answers these basic questions about B. burgdorferi, they are contributing to our broader understanding of how bacteria make people sick, and how we can treat infection.

"A lot of the major advances that affect health care, and that affect treatment of different diseases, arise from people exploring scientifically," says Dr. Moriarty. "The ideas that we develop and test, even if they don't immediately seem they could be important, in fact could end up being the idea that's important for treating a disease."

She and her team are also working to establish collaborations with clinicians and public health officials, so they can work together to understand which strains of B. burgdorferi are entering the country, how they are spreading, how they are causing disease, and how we can stop them.

For more information on Lyme disease, visit Health Canada's website.

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