The National Microbiology Laboratory helps to bring modified Lyme disease testing techniques to Canada

May 1, 2024


Dr. Heather Coatsworth is passionate about bugs.

So much so, she has made it part of her life’s work. An entomologist by training, she has brought this passion to her role as Chief of the Field Studies program at the Public Health Agency of Canada’s (PHAC) National Microbiology Laboratory (NML), where part of her job is researching Lyme disease.

Dr. Heather Coatsworth, Chief of Field Studies, NML

Dr. Heather Coatsworth, Chief of Field Studies, NML

Lyme disease (caused by infection with Borrelia burgdorferi) rates in Canada are driven by the rapid northwestern spread of the blacklegged tick. Lyme disease went from a rare occurrence in Canada in 2006, to endemic (regularly occurring) throughout most of southern Canada as of 2023. Dr. Coatsworth says there continues to be an increasing number of samples collected from humans sent for Lyme testing. In addition, the number of infected blacklegged ticks submitted as part of tick surveillance programs continues to increase. Lyme disease can progress into post-treatment Lyme disease syndrome, which is associated with long-term illness, highlighting the need for increased education, diagnosis and treatment.

This work hits close to home for Dr. Coatsworth, whose mother has post-treatment Lyme disease syndrome. Seeing how the disease has affected her mother has shaped her perspective, and drives her work at the NML to advance Lyme disease testing methods, continue research into the disease and increase awareness.

Dr. Coatsworth and her mother at the TickNet Canada symposium.

Dr. Coatsworth and her mother at the TickNet Canada symposium.

“There’s a personal piece to me being in this space and it is really encouraging to see the changes in access, understanding and knowledge when it comes to Lyme disease. It’s great to be part of those discussions and to see where it’s going,” says Dr. Coatsworth.

Modified testing techniques for Lyme disease

The Field Studies section, led by Dr. Coatsworth, focuses on human diagnostics, monitoring and research related to zoonotic (animal) and tick-borne pathogens that are infectious to humans. One of their responsibilities is the development and evaluation of diagnostic testing.

The Field Studies section assisted provinces in validating a new Lyme disease testing process for serological (blood) testing, called Modified Two-Tier Testing (MTT), which detects the presence of human antibodies to the Lyme disease pathogen,. The standard testing algorithm (STT), which was the only testing method used before the MTT was validated, while comparable in specificity and sensitivity, produces complex results that can be difficult to interpret. The modified method is faster and easier to interpret for health care practitioners. MTT has also allowed provinces to take on the testing themselves and streamline Lyme testing. In addition, the NML performs molecular testing for early stage cases of Lyme disease on tissue and synovial fluid (liquid found in your joints) samples. The NML continues to offer STT testing for non-endemic areas of Canada, for difficult to interpret or unique cases, and as quality assurance when confirmation of a result is needed.

Lyme disease research at NML

The NML continues to work on finding new Lyme testing methods for human samples, including a target for the early stages of infection as well as for post-treatment Lyme disease syndrome. They are also working on expanding testing for European Lyme, as well as neurological Lyme. The NML works with provincial, territorial and international partners so that Health Canada approved Lyme testing is accurate and sensitive. The team collaborates with networks and researchers across Canada to collect animal and tick samples to better understand the genetic diversity of the Lyme disease pathogen, estimate current and future risk, analyze the climatic tolerance of blacklegged ticks in Canada and assess the effectiveness of tick reduction strategies.

In addition to her personal connection to the disease, Dr. Coatsworth is motivated by working with partners, research networks, medical professionals and patient groups to provide support and share knowledge. All these groups work together to urge patients to use accredited testing methods.

“I think everyone in public health has the lens of working for a bigger picture that isn't just ourselves. I like having that connectivity, especially when it's difficult to feel connected to all of Canada because we're such a big place.”

Collecting tick samples in the field.

Collecting tick samples in the field.

A scientist examines ticks under a microscope.

A scientist examines ticks under a microscope.

Prevention and early treatment are key

There is now more knowledge regarding the symptoms, diagnosis and treatment of Lyme disease, including post-treatment Lyme disease syndrome. While laboratory tests play in a role in providing evidence to support a diagnosis, Lyme cases are primarily diagnosed clinically, with a focus on early treatment through antibiotics.

The best way to protect against Lyme disease is to prevent tick bites. Follow these tips:

  • Wear light-coloured long-sleeved shirts and pants.
  • Tuck your shirt into your pants, and your pants into your socks.
  • Wear closed-toe shoes.
  • Use bug spray with DEET or Icaridin (always follow label directions).
  • Walk on cleared paths or walkways.
  • Shower or bathe as soon as possible after being outdoors.
  • Do a daily full body tick check on yourself, your children, your pets and your gear.
  • Put your clothes in a dryer on high heat for at least 10 minutes.

For more information about PHAC’s tick and Lyme disease surveillance system and to check if you live in a Lyme disease risk area, visit and enter your postal code.