An increase in Lyme disease cases is a concern, Canada's top public health officer says.

Lyme disease is an infection caused by Borrelia burgdorferi bacteria. In Canada, it's transmitted by two species of ticks that suck on the blood of humans and other animals. Ticks look like a small, flat watermelon seed.

In 2015, there were more than 700 cases of Lyme disease reported to the Public Health Agency of Canada. In 2009, there were 128 cases.

"We think the numbers are much higher and it's alarming that the numbers are increasing continuously," said Dr. Gregory Taylor, the country's chief public health officer.

Taylor expects the true number of cases is much higher since mild cases may clear on their own, or may never be reported to public health authorities, even though it it's been nationally notifiable since 2009.

If detected early, the treatment is a short course of antibiotics that cures the majority of people. Left untreated, it can result in facial palsy, meningitis, heart problems, nerve damage and inflammation of the brain and spinal cord.

It's worrisome that something so easy to treat can sometimes have such an impact on people, Taylor said.

The easiest way to deal with Lyme disease is to protect yourself when going into areas where ticks live, such as woodlands or where there are leaves or tall grass on the ground.

Michael Chardavoyne helps his wife, Sarah Chardavoyne, who has suffered from Lyme disease for many years. Canada is hoping to improve surveillance of ticks and treatment of the disease. (Craig Rubadoux/Florida Today/Associated Press)

Step one is avoidance. If you live in a tick zone, remove leaf litter and tall grass around your house to reduce their numbers.

Recommended precautions include:

Cover up with light-coloured clothing to spot ticks more easily.

Walk in the centre of designated trails.

Wear closed-toed shoes.

Tuck your pant legs into your socks to prevent ticks from crawling up your legs.

Tuck your shirt in to prevent ticks from getting onto your skin.

Use insect repellents that contain DEET or Icaridin.

Have a friend give a quick scan at regular intervals to check if a tick is crawling on you.

Shower or bathe within two hours of being outdoors to wash away loose ticks.

When you return home, change your clothes and hang the clothes outside so ticks don't enter the house. A run through the dryer will kill ticks more effectively than the washer, said Janet Sperling, an entomologist at the University of Alberta and a board member of the Canadian Lyme Disease Foundation, an advocacy group.

Ticks are tied to reservoirs of deer and field mice populations, said Sandy Smith, a professor in the forestry faculty at the University of Toronto. Smith studies invasive forest pests and became interested in Lyme disease when she found a tick had climbed up her sleeve in a wooded area in Norfolk in southwestern Ontario.

Ticks like dark and quiet

The eight-legged critters can't fly or jump. They lurk on grass or shrubs and climb onto a passing host.

In most cases, the tick must be attached for 36 to 48 hours or more before Lyme disease bacteria can be transmitted, the U.S. Centers for Disease Control and Prevention says. Smith found her tick in just a few hours.

"Ticks like it where it's dark and quiet," Smith said. That's why it is so important to check for ticks if you've been out in tick areas.

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Undress, look under arms and in and around ears, in the belly button, back of the knees and around the waist and have a family member or close friend check the rest.

The tick will protrude but can be quite small, Smith said. Check children and pets, too, especially dogs. They can easily pick up ticks when walking in the woods.

Test and treatment controversy

Taylor said his major concern is the full impact of Lyme disease isn't known.

"I say we've got some folks saying the numbers could be in the thousands and thousands rather than hundreds. The more people are infected, the more cases of severe outcomes we're going to see," Taylor said.

This week, the Public Health Agency of Canada held a conference on Lyme disease, which covered enhanced surveillance, treatment guidelines and best practices, and education and awareness for clinicians on what to look for and how to treat it.

Tick surveillance depends on people submitting ticks for identification and testing in parts of the country where Lyme disease is not yet regularly found, as well as actively testing ticks for the bacteria.

Taylor acknowledged there's a division in Canada on how to interpret the blood test for Lyme disease and how to treat it. While mainstream physicians in Canada and the U.S. following criteria from the Centers for Disease Control and Prevention wouldn't put patients on antibiotics for several months, some clinicians do.

But long-term antibiotic treatment does carry risks of promoting antibiotic resistance and patients may develop severe diarrhea, Taylor said. The consensus is better, easier to interpret tests are needed, he said.

More than 100 people were interested in publicly speaking about their experience with Lyme disease at the conference. They spoke of trouble getting a diagnosis and treatment, said Susan McInnis of the Lyme Disease Association of Alberta.

"Diagnostic tests are failing Canadians and I hope to see better public awareness directed to this fact. A clinical diagnosis must be supported and doctors given freedom from persecution for treating chronically ill cases of Lyme disease," McInnis said Tuesday as the conference concluded.

For the conference to be a success, the momentum needs to continue, McInnis said.

The Public Health Agency of Canada said it is evaluating the performance of a new test on blacklegged ticks collected from people from across Canada to ensure it provides accurate and reliable information.