Doctors and government are sounding the alarm on tick-borne diseases as the first blacklegged ticks of the season have been discovered in Manitoba.
Lyme disease, the illness most associated with the blacklegged tick and a growing villain in the minds of Manitobans, once again tops the province’s tick-related health concerns.
Last year saw the highest rate of Lyme disease since statistics were first collected in 2009. There were 62 potential cases in Manitoba in 2016, up from 39 in 2015 and 48 in 2014.
The infection, often typified by a bull’s-eye-shaped rash (although not present in all cases), first causes headache, fever, aches and pains, stiff neck, swollen lymph nodes and fatigue before manifesting more serious symptoms. Left untreated, the disease has been known to cause joint, heart and nervous system problems and, even after successful treatment, symptoms can persist for years.
Dr. Michael Routledge, medical officer of health with the Southern Health Region, says the disease is commonly contracted early in the tick season, as ticks are less likely to be removed during the 24-hour grace period before disease transmission.
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“We tend to see more cases this time of year because, No. 1, the ticks are out, but also they’re quite small at this time of year but they’re at a stage where they can transmit,” he said.
Less than one-third of Lyme patients recall being bitten by a tick, the province has said, while blacklegged ticks may be active as soon a temperatures rise consistently above 4 C.
The Pembina Valley, Red River Valley corridor and southeast Manitoba, all areas with known blacklegged tick populations, lie within the Southern Health Region. Nineteen cases of Lyme disease were reported in the Southern Health Region last year, up from 14 in 2015.
Routledge identified both growing tick populations and growing awareness of Lyme disease as reasons for the increase. He noted however, that the condition is still comparatively rare.
While Manitobans have long been used to dog ticks, which are not known to carry Lyme disease, the blacklegged tick is a relatively recent interloper. The province has seen a westward spread of the pest in recent decades. In 2011, the province first confirmed populations in the Pembina Valley Region, now a hot spot for the pest. At the time, over one-third of tested ticks in the region were positive for Lyme-causing bacteria.
Blacklegged tick risk zones now run through south-central Manitoba, as far north as the Interlake and as far west as Brandon.
Dr. Amy Frykoda, officer of medical health for the Prairie Mountain Health Region, says four cases of Lyme disease were reported last year, up from two in both 2015 and 2014.
“The general message is that we are seeing a steady increase in case numbers of the blacklegged tick risk areas than we’ve seen in the past,” she said.
There was an average 1.2 Lyme disease cases per year in the Prairie Mountain Health Region from 2011 to 2015.
“It is possible to find blacklegged ticks in areas outside the known blacklegged tick risk areas of Manitoba because ticks can attach to migrating birds and be carried over large distances,” Manitoba Health, Seniors and Active Living has said. “However, the disease risk is relatively low because the chance of encountering infected blacklegged ticks is less likely outside of these risk areas.”
Interestingly, Routledge has said, many Lyme cases seem to stem from those living in urban centres rather than farms. Little comprehensive data has been collected on patient career, but Southern Health has not seen any ties between Lyme disease and agriculture, which takes place mostly outdoors, he said.
“Anybody who’s spending lots of time outdoors is at risk, but it’s not surprising in the sense that where we tend to see these populations is more away from what I would call agricultural areas. It tends to be more in a wooded area,” he said.
He acknowledged that some aspects of agriculture would put producers in contact with Lyme disease risk zones.
Frykoda says cases to the west have been largely balanced between rural and urban populations. She noted that some producers may live in towns, but contract the disease on rural farms.
“The other thing that could be happening when you’re finding this information surprising, but it may not be surprising, is just that there are higher population numbers in an urban centre,” she said.
Two other tick-borne diseases, anaplasmosis and babesiosis, have also warranted public alerts this year. A record 17 potential cases of anaplasmosis and the province’s first potential case of babesiosis were reported last year. Anaplasmosis, which causes fever and flu-like symptoms, generally appears between five and 21 days after an infected tick bite and generally resolves itself within 30 days. For the elderly or those with compromised immune systems, however, the risks are higher. Severe cases of anaplasmosis have caused respiratory and neurological problems, infection, kidney failure or even death.
Babesiosis, typically manifesting one to six weeks after the bite, proves a particular challenge as most cases will develop no symptoms. For those who do, fatigue is a common first indicator, followed by any of the following: chills and sweating, severe appetite loss, anemia, headaches and weakness, joint pain, nausea or a persistent, unproductive cough. Like anaplasmosis, babesiosis may require hospitalization, while fatigue, weakness and anemia may persist for months after treatment.
An online tick checker tool has been introduced this year in an effort to better track the blacklegged tick population. The public is asked to submit pictures and information at http://forms.gov.mb.ca/tickSubmission/. Information will be used to direct tick-scouting efforts.
“Certainly, over the last number of years we’ve often had people asking about how they can submit a tick for assessment,” Routledge said. “This is just another sort of tool that we developed and Manitoba Health has developed in order to be able to facilitate that.”
There have been no cases of anaplasmosis in the Prairie Mountain Health Authority, although Frykoda says that may change as tick populations continue to spread.