A rare and life-threatening disease called babesiosis is slowly spreading in Canada with the help of an eight-legged, blood-sucking arachnid — the blacklegged tick.
The blacklegged ticks, also known as deer ticks, can transmit babesiosis, an infection similar to malaria. Although rare in Canada, this tick-borne illness is becoming more prevalent in some provinces and in parts of the northeast United States.
Babesiosis can be a serious, fatal disease, especially for the elderly and people who are immunosuppressed, according to the U.S. Centers for Disease Control and Prevention (CDC). It can also cause life-threatening complications, including renal, liver and heart failure and respiratory distress syndrome.
South of the border, the CDC reported in March that the tick-borne parasitic disease is on the rise in northeastern states. Babesiosis is now considered endemic in three new states: Maine, New Hampshire and Vermont.
In Canada, babesiosis became a provincially reportable disease in Manitoba in 2015.
Ticks can be active at temperatures of 4 C and above, which can be in every season, even in the winter. In Canada, the peak tick season lands between mid-spring and early fall.
“We are seeing more ticks, we’re seeing ticks spread into new areas in Canada,” explained Justin Wood, founder of Genetics, a Canadian-based lab that tests tick-borne diseases. “Which means there will probably be a rise in cases.”
Part of the reason tick-borne diseases, such as babesiosis, are on the rise is that climate change has led to more suitable environments for ticks to thrive in, such as shorter winters leading to improved reproduction and longer seasonal activity, he said.
“We seem to be having less intense winters, which can contribute to the survival rate of ticks,” Wood said.
“And the biggest contributor is that shorter winters mean there’s a more active time for ticks, and that means there’s more time for ticks to find hosts to feed and to progress through their life cycle.”
Babesiosis in Canada
Babesiosis has typically been spread in North America by two parasite species: Babesia microti (the tick-borne disease spreading in the U.S.) and Babesia duncani (an emerging tick-borne pathogen that is mainly on the Pacific coast).
The parasite is commonly spread to humans during the tick’s nymphal stage, through its saliva when it bites into the skin. The nymph is typically the size of a poppy seed, so many people may be unaware they have a bite.
Babesiosis can be transmitted by ticks at various stages of their development, it is just not as common.
Until recently, babesiosis was not found in Canada, according to a 2021 study in the Canadian Medical Association Journal (CMAJ).
However, with climate change and the help of migratory birds, more blacklegged ticks are travelling north, and are growing in numbers in places like Manitoba, Ontario, Quebec, Nova Scotia and New Brunswick. They are also bringing babesiosis with them.
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In 2013, the first human case of Babesia microti in Canada was reported in Manitoba after a child with a “complicated medical history” became infected with the disease. Since then, it has been reported in other provinces such as British Columbia, Ontario, Quebec, New Brunswick and Nova Scotia.
And in 2017, the first reported human case of Babesia duncani was found in a 70-year-old man in southern Ontario after a deer tick bite.
A 2014 study predicted that the risk of infection from tick-borne diseases (such as babesiosis) is increasing in eastern and Central Canada and spreading north at an estimated rate of 33-55 kilometres per year.
Although on the rise, the species Babesia microti and Babesia duncani are still rare, explained Wood, adding there is another more concerning species to watch for called Babesia odocoilei.
A 2021 study out of Diagnostics found that Babesia odocoilei was prevalent in blacklegged ticks in certain parts of Ontario.
“The original work looked at just one area in Ontario, and since then we’ve been testing ticks all across Canada. We found it almost everywhere,” he said.
How is babesiosis different from Lyme disease?
Lyme disease is the most common tick disease in Canada and is primarily spread by deer ticks. It’s been on the rise in the country over the last decade due to climate change.
In 2021, there were 3,147 reported cases of Lyme Disease across Canada – up from just 144 cases reported in 2009, according to the latest Health Canada data.
Lyme disease is caused by a bacteria called Borrelia burgdorferi and is transmitted through the bites of infected deer ticks.
The symptoms of Lyme disease depend on how long the infection has been present in the body.
The first sign is often an expanding round or oval red “bullseye” rash, according to Johns Hopkins Medicine. Other symptoms include fever, chills, headache and vomiting, which typically show up within hours or days of being bitten.
Babesiosis, meanwhile, is caused by a tiny parasite called Babesia that infects red blood cells and is transmitted primarily through the bite of blacklegged ticks. Like Lyme disease, it is transmitted through the bite of a deer tick.
Some cases are completely asymptomatic, but others come with fever, muscle aches, muscle pain, joint pain and other symptoms. Unlike Lyme disease, babesiosis doesn’t cause a rash.
Mortality rates for those infected with babesiosis are around five per cent, but can be as high as 21 per cent among hospitalized and immuno-compromised patients, according to Manitoba Public Health.
Lyme disease is rarely fatal, but the CDC reported that there have been 11 Lyme-disease related worldwide between 1985 and 2019.
Danial Cameron, an epidemiologist based in New York, specializes in the treatment of Lyme disease. Because both Lyme disease and babesiosis are transmitted by the same tick, a person can be infected with both illnesses, he explained.
Babesiosis cannot be treated with the same medications used to treat Lyme disease, as one is a parasite and another is a bacteria, Cameron said. But if a person is infected with both illnesses, they can receive both antibiotic and antimicrobial medication.
“In the belly of a tick, there is quite a range of different bacteria, parasites and viruses,” he said. “If you mix the two that people with Lyme and babesiosis at the same time, their condition was more severe,” he said.
How can Canadians protect themselves?
Blacklegged ticks live in forested areas, tall grasses and bushes, explained Dr. Nicholas Ogden, a research scientist and director of the public health risk sciences division with the National Microbiology Laboratory.
The main period of risk for contracting a tick-borne illness, such as Lyme disease or babesiosis, is when nymph ticks are active, as they have higher numbers than adult ticks.
“They are about the size of a sesame seed, and they are the main cause of transmission of Lyme disease because they are so small and you are likely to miss them,” he said.
Nymphs are active from mid-spring to mid-summer and adult ticks are active in early spring and fall.
Ogden suggests that people “wear clothing that limits the tick getting onto the skin and burying its head” as well as apply insect repellent containing DEET. He said people can even tuck their pants into their socks to prevent the tick from climbing up their legs.
“When you return home after being out in the woodlands, you should conduct a tick check to see if you can find a tick that has attached, and remove them. This certainly helps prevent Lyme disease and other tick-borne illnesses.”
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