The rise of the tick

If you enjoy being outdoors, chances are you’ve received your fair share of bug bites.  Some may cause itchiness or a skin rash, but other bites can sometimes lead to a serious health issue. Take Lyme disease for example; it’s an infection from a bacterium called Borrelia burgdorferi. The bacterium is transmitted to humans from the bite of infected blacklegged ticks and may lead to severe symptoms if left untreated.

Reports of Lyme disease in Canada are on the rise and the little bugs are growing in numbers in new areas, likely due in part to the warming effects of climate change. So now more than ever, we rely on science to help us understand how this disease is spreading.

On the watch

The Public Health Agency of Canada (PHAC) is continuing to work on Lyme disease surveillance. What is that you ask? Basically, scientists monitor data on reports of where the disease occurs by person, place and time. Accurate reporting of Lyme disease cases is important to better understand the health issue and the geographical spread.

The proportion of Lyme disease infected ticks in specified areas is also being monitored.

Lyme disease surveillance is not a solo job.  That’s why PHAC has teamed up with partners and stakeholders--such as Canadian universities, organizations, and provinces and territories--to provide better surveillance that shows a clearer picture of the situation.

How is it done?

Canadian Lyme disease surveillance is led by PHAC and is done in one of three ways:

1.       Passive tick surveillance involves testing ticks found on humans (and domestic animals in some regions) that are submitted voluntarily by the public and health care professionals. Tick specimens collected are shipped to the provincial Public Health Laboratories for species identification. Any blacklegged ticks identified are sent to the PHAC’s National Microbiology Laboratory (NML) to test for the presence of disease-causing bacteria.

2.       Active tick surveillance  (also known as tick dragging) is conducted by PHAC researchers going out to areas that are suspected to have a high population of ticks and then dragging flannel-like blankets through fields to collect ticks for diagnostic testing at the NML (Yes – this IS a government job!).  

3.       Human case reporting is done in collaboration with some provincial and territorial public health organizations by reporting human Lyme disease cases to PHAC via the Lyme Disease Enhanced Surveillance system.

The ticks are ticking

Our lab scientists analyze the data collected from the various surveillance methods to help determine such things as the level of risk to Canadians. Predictive risk maps have been developed using the data to pinpoint Lyme disease “hotspots”. Scientists have found that the annual number of nationally reported cases has been steadily rising each year, from 128 in 2009 to 522 in 2014. Preliminary numbers for 2015 report 707 cases.

The study also shows that most cases of Lyme disease are acquired where tick populations are spreading and that how fast and how far they are spreading varies among provinces. “Lyme disease is emerging in Canada due to the spread of the ticks that transmit it -- but there is a lot of variation from province to province in how common that spread is,” says scientist Dr. Nick Ogden.

Working together

A collaborative approach is needed to tackle Lyme disease -- from sharing surveillance to better understand this health threat, to working together to improve how the disease is prevented, identified, treated and managed. From May 15 to 17, PHAC hosted a national conference that brought together stakeholders, experts and other interested parties to help with the development of a comprehensive Federal Framework on Lyme Disease.

To learn more about Lyme disease, and how you can protect yourself and spread awareness, visit