It’s peak season for another infectious disease waiting for Canadians in parks and campgrounds

As Canadians rush outdoors after weeks in lockdown, researchers and public-health officials warn of a less novel, but ever-increasing infectious villain waiting for them in the woods: the black-legged ticks.

The timing could not be worse: peak season for the tiny bug, which carries the bacteria that causes Lyme Disease, is happening just as governments across the country lift restrictions on parks and camping areas.

A collection of new cases presented in the Canadian Medical Association Journal on Monday details the rare but deadly health consequences of Lyme disease, especially when it is not detected early.

The cases include the death of a healthy, 37-year-old Manitoba man two summers ago after he was diagnosed with Lyme carditis, a condition that occurs when the bacteria that causes Lyme interferes with the heart’s electrical signals. It causes dizziness, fainting and a slowing heartbeat, and can eventually lead to what scientist call a heart block. The man had been bitten by a tick weeks earlier, but the diagnosis came too late: by the time he was admitted to hospital and given intravenous antibiotics, the damage to his heart was too severe. He died 48 hours later.

The doctors involved with the cases say that they are trying to raise awareness both of the need for prevention by the public and vigilance for physicians, especially those in rural emergency departments.

“We are not trying to scare people, but we want to highlight the disease,” said Richard Rusk, a primary physician and public-health officer who co-authored the paper about the Manitoba case.

Dr. Rusk worries that a country already exhausted by messaging about physical distancing and hand-washing may not heed this instruction: when walking through long grass, forests and off-trail, wear repellent, long sleeves and tuck your socks into pants.

If you spend time in nature where the presence of ticks is high – which includes the entire province of Nova Scotia, swathes of Manitoba, much of Vancouver Island, as well as areas in and around cities such as Ottawa and Toronto – conduct a tick check each night. Unlike mosquitoes, ticks often don’t sting when they latch on to a host. They can be as small as a grain of sand, so easily overlooked.

Cases of Lyme disease have grown exponentially in Canada over the past decade. According to national surveillance statistics, the number of cases was 2,025 in 2017, compared with 144 in 2009. Scientists believe a major factor in their advance north is climate change.

The chances of being infected with Lyme disease from a tick bite are about 3 per cent to 5 per cent according to research. But the percentage of Lyme disease cases that develop into heart problems may be up to 10 per cent, said Adrian Baranchuk, a cardiologist and researcher in Kingston, Ont. “If it goes undiagnosed, the possibility of having serious complications is not that small,” he said.

In another case reported in CMAJ, Dr. Baranchuk treated a 56-year-old female patient in Kingston who was diagnosed with Lyme carditis after being bitten by a tick while jogging. She recovered after a dose of intravenous antibiotics. In the past, many of these cases have resulted in younger patients being given pacemakers, but Dr. Baranchuk says there is now enough good evidence – led by research done in Kingston – to support the less invasive, less costly approach of a round of antibiotics and careful monitoring.

This depends, however, on doctors identifying cases quickly, which can be complicated because people may not remember being bitten, and the symptoms of Lyme often resemble those of other illnesses. What’s more, only about half of the people bitten by a tick get the classic bulls-eye rash, Dr. Baranchuk said. In the case of his female patient, her rash appeared as a reddish blotch and was first treated as cellulitus, a common skin infection. She was only properly diagnosed when she returned to emergency 15 days later with palpitations and light-headedness.

The cases described in the CMAJ further highlight how easily Lyme Disease may be overlooked. In the family account of the case involving the Manitoba man, Samuel, his sister writes that at a family swimming gathering she noticed circular rashes on his chest and back, but Samuel did not recall being bitten by a tick. A visit to the doctors returned a diagnosis of a bad flu. He seemed better at the next family gathering for his 37th birthday. But about a week later, he messaged his family that he was being kept over night at hospital for “minor heart symptoms.” The next day, she says, they rushed to the hospital to find him on life support.

A third case reported in the CMAJ involved a four-year-old Ontario boy brought to hospital with symptoms of fever, vomiting, as well as a condition called ataxia, which affects muscle co-ordination and speech. A picture provided by his parents showed a tick-like rash four months earlier, and led doctors to diagnose Lyme Disease and successfully treat the boy with antibiotics.

To improve the chances of catching serious problems in time, the CMAJ paper recommends that patients suspected or confirmed to have Lyme Disease be checked for heart symptoms, and, if discharged, told to seek immediate care if symptoms develop.

But ultimately, the experts say, the best treatment is prevention.

In Mahone Bay, N.S., Lisa Ali Learning discovered this the hard way when her two sons, then 11 and 9, came down with mysterious swollen joints, eventually found to be caused by tick-borne disease. They recovered with antibiotics but “it was huge eye-opener,” said Ms. Learning, who, with an Acadia University researcher, went on to develop a natural spray that is awaiting approval from Health Canada as a tick repellent. “I was completely ignorant, and that was a problem.” Now her family is vigilant about daily tick checks.

Dr. Rusk offered this advice: “We don’t say people are weird for wearing a mask, we say that’s appropriate.” It’s the same with tucking your pants into your socks when you enjoy the woods – another new normal so Canadians can stay safe outdoors.

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