Ontario Tick and Lyme Disease Statistics 2026

Ontario reported 2,369 Lyme disease cases in 2024, more than any other province. All of Halton Region is an established blacklegged tick risk area, and all of Toronto an estimated one. This page brings together official numbers and key research findings on ticks and tick-borne disease in Ontario, from Public Health Ontario, the Public Health Agency of Canada, Halton Region, Toronto and Peel public health, and peer-reviewed studies. Every number has its publisher, date and a link right under it.

Key Takeaways

Ontario reported 2,369 of Canada's 5,809 Lyme disease cases in 2024, the most of any province.Source: Public Health Agency of Canada, Annual report: Tick-borne disease surveillance in Canada (January 2026)
Lyme disease cases reported in Ontario rose 27% in 2024 compared with the year before.Source: Public Health Agency of Canada, Annual report: Tick-borne disease surveillance in Canada (January 2026)
Canada's reported Lyme disease cases rose from 144 in 2009 to 5,809 in 2024, and the preliminary count for 2025 is 7,105.Source: Public Health Agency of Canada, Lyme disease: Monitoring (July 2026)
Halton Region Public Health considers all of Halton Region an established blacklegged tick risk area.Source: Halton Region Public Health, Lyme Disease and Other Tick-Borne Diseases (page as of May 2026)
Adding up the four Oakville sites where Halton Region found blacklegged ticks in 2025, 29 of the 72 ticks tested carried the Lyme disease bacterium (our total of Halton's site figures).Source: Halton Region Public Health, Lyme Disease and Other Tick-Borne Diseases (page as of May 2026)
The share of Halton ticks testing positive for the Lyme disease bacterium rose from 17% in 2023 to 27% in 2024, and to 38% in ticks collected in spring 2025.Source: Halton Region Public Health, West Nile virus, Lyme disease and Anaplasma are active (physician update) (July 2025)
All of Toronto is considered an estimated blacklegged tick risk area.Source: Toronto Public Health, Lyme Disease (accessed October 2026)
Public Health Ontario's 2025 risk area map added 13 new blacklegged tick risk areas, including two in Peel.Source: Public Health Ontario, Public Health Ontario Launches New Ontario Vector-Borne Disease Tool (June 2025)
In 2022, 27.4% of blacklegged ticks collected by tick dragging in Ontario tested positive for Borrelia burgdorferi, the bacterium that causes Lyme disease.Source: Public Health Agency of Canada, Canada Communicable Disease Report, Surveillance for Ixodes scapularis and Ixodes pacificus ticks and their associated pathogens in Canada, 2022 (February 2026)
More than 80% of cases of Ontario's four reportable tick-borne diseases have onset dates between May and October.Source: Public Health Ontario, Tick-Borne Diseases in Ontario: An Update (PHO Rounds) (May 2026)
In most cases, an infected tick must be attached for at least 24 hours before it passes on the Lyme disease bacterium.Source: Public Health Agency of Canada, Lyme disease: For health professionals (July 2026)
Of Ontario's confirmed and probable Lyme disease cases from 2023 to 2025, 3.8% were hospitalized and no deaths were reported.Source: Public Health Ontario, Tick-Borne Diseases in Ontario: An Update (PHO Rounds) (May 2026)
Ontario recorded 112 hospitalizations (21.1% of cases) and 4 deaths among anaplasmosis cases from 2023 to 2025.Source: Public Health Ontario, Tick-Borne Diseases in Ontario: An Update (PHO Rounds) (May 2026)
In 2025, the bacterium that causes Rocky Mountain spotted fever was found in American dog ticks at Long Point, the first such detection in Ontario in over 50 years.Source: Public Health Ontario, Hazard Identification and Risk Assessment: Climate Change and Vector-borne Diseases (May 2026)

How many Lyme disease cases does Ontario report each year?

Ontario reported 2,369 Lyme disease cases in 2024, the most of any province and 27% more than the year before, according to the Public Health Agency of Canada. Incidence in Ontario increased 3-fold from 2015 to 2022.

Ontario reported 2,369 of Canada's 5,809 Lyme disease cases in 2024, the most of any province.Source: Public Health Agency of Canada, Annual report: Tick-borne disease surveillance in Canada (January 2026)
Lyme disease cases reported in Ontario rose 27% in 2024 compared with the year before.Source: Public Health Agency of Canada, Annual report: Tick-borne disease surveillance in Canada (January 2026)
Ontario reported 1,859 Lyme disease cases to the Public Health Agency of Canada in 2023.Source: Public Health Agency of Canada, Annual report: Tick-borne disease surveillance in Canada (January 2026)
Ontario accounted for 39% of Canada's reported Lyme disease cases in 2023, behind Nova Scotia at 43%, with most Ontario cases in the south-eastern part of the province.Source: Public Health Agency of Canada, Annual report: Tick-borne disease surveillance in Canada (January 2026)
Ontario reported 1,478 Lyme disease cases in 2022: 1,406 confirmed and 72 probable.Source: Public Health Agency of Canada, Lyme disease surveillance in Canada: Annual edition 2022 (April 2024)
Ontario's Lyme disease incidence rate was 9.78 cases per 100,000 population in 2022.Source: Public Health Agency of Canada, Lyme disease surveillance in Canada: Annual edition 2022 (April 2024)
Ontario reported 7,762 Lyme disease cases from 2015 to 2022, of which 7,213 (92.9%) were confirmed and 549 (7.1%) were probable.Source: Emerging Infectious Diseases (Adams JA, Nelder MP et al.), Age- and Sex-Specific Differences in Lyme Disease Health-Related Behaviors, Ontario, Canada, 2015-2022 (October 2024)
Lyme disease incidence in Ontario increased 3-fold from 2015 to 2022.Source: Emerging Infectious Diseases (Adams JA, Nelder MP et al.), Age- and Sex-Specific Differences in Lyme Disease Health-Related Behaviors, Ontario, Canada, 2015-2022 (October 2024)
Of confirmed and probable Lyme disease cases reported in Ontario from 2023 to 2025, 281 (3.8%) were hospitalized and no deaths were reported.Source: Public Health Ontario, Tick-Borne Diseases in Ontario: An Update (PHO Rounds) (May 2026)

How fast are Lyme disease cases rising across Canada?

Canada reported 5,809 Lyme disease cases in 2024, up from 144 in 2009, and the preliminary count for 2025 is 7,105. Ontario, Nova Scotia and Quebec reported 96% of the 2024 cases.

Lyme disease cases reported in Canada by year, as a table
Year	Cases
2009	144
2010	143
2011	266
2012	338
2013	682
2014	522
2015	917
2016	992
2017	2,025
2018	1,487
2019	2,634
2020	1,617
2021	3,147
2022	2,525
2023	4,785
2024	5,809
2025 (preliminary)	7,105

The Public Health Agency of Canada notes that the national case definition was revised in 2016 and in 2024, which may affect trends.Source: Public Health Agency of Canada, Lyme disease: Monitoring (July 2026)

Canada reported 5,809 human cases of Lyme disease in 2024, annual growth of over 20%.Source: Public Health Agency of Canada, Annual report: Tick-borne disease surveillance in Canada (January 2026)
PHAC says the jump in reported cases in 2023 is partly due to a change in Nova Scotia's provincial case definition that year.Source: Public Health Agency of Canada, Annual report: Tick-borne disease surveillance in Canada (January 2026)
Canada's preliminary count for 2025 is 7,105 reported human cases of Lyme disease.Source: Public Health Agency of Canada, Lyme disease: Monitoring (July 2026)
The incidence of Lyme disease in Canada was 14.1 cases per 100,000 population in 2024, up from 11.9 per 100,000 in 2023.Source: Public Health Agency of Canada, Annual report: Tick-borne disease surveillance in Canada (January 2026)
Ontario (41%), Nova Scotia (40%) and Quebec (14%) reported most of Canada's 2024 Lyme disease cases; PHAC puts the three provinces together at 96% (shares are rounded).Source: Public Health Agency of Canada, Annual report: Tick-borne disease surveillance in Canada (January 2026)
Nova Scotia had the highest Lyme disease incidence of any province in 2024, at 217 cases per 100,000 population.Source: Public Health Agency of Canada, Annual report: Tick-borne disease surveillance in Canada (January 2026)
Ontario accounted for 46.0% of all Lyme disease cases reported in Canada from 2009 to 2019, and Ontario, Nova Scotia and Quebec together for 92.1%.Source: Public Health Agency of Canada, Canada Communicable Disease Report, Surveillance for Lyme disease in Canada, 2009 to 2019 (May 2022)
Canada had an estimated 40 reported human cases of Lyme disease in 2004, a number that rose to 682 in 2013.Source: Canadian Veterinary Journal (Bouchard C et al.), The increasing risk of Lyme disease in Canada (July 2015)

Are there Lyme disease ticks in Oakville and the rest of Halton?

Yes. Halton Region Public Health considers all of Halton Region an established blacklegged tick risk area, and 41 of the 106 blacklegged ticks it tested in 2025 carried the Lyme disease bacterium. In May 2024, Halton Region Public Health said the risk of getting Lyme disease in Halton remained low, while locally acquired cases were trending upward.

Halton Region tick dragging, 2025: sites where blacklegged ticks were found
Town	Site	Ticks tested	Carried Lyme bacteria
Oakville	Langtry Park	25	7
Oakville	Sedgewick Forest	23	13
Oakville	Aspen Forest Trail	20	8
Oakville	McCraney Valley Trail	4	1
Burlington	Hidden Valley Park	6	3
Milton	Robert Edmundson Conservation Area	10	3
Milton	Rattlesnake Point	8	3
Milton	Drumquin Park	4	2
Halton Hills	Acton Rotary Park	3	1
Halton Hills	Halton Regional Forest, Acton Tract	3	Not reported

By our count, Halton lists 21 sites; the 11 where no blacklegged ticks were found are left out.Source: Halton Region Public Health, Lyme Disease and Other Tick-Borne Diseases (page as of May 2026)

Based on its spring and fall tick dragging, Halton Region Public Health considers all of Halton Region an established blacklegged tick risk area.Source: Halton Region Public Health, Lyme Disease and Other Tick-Borne Diseases (page as of May 2026)
Halton Region Public Health tested 106 blacklegged ticks in its 2025 tick surveillance, and 41 were positive for Borrelia burgdorferi, the bacterium that causes Lyme disease.Source: Halton Region Public Health, Lyme Disease and Other Tick-Borne Diseases (page as of May 2026)
Adding up the four Oakville sites where Halton Region found blacklegged ticks in 2025, 29 of the 72 ticks tested carried the Lyme disease bacterium (our total of Halton's site figures).Source: Halton Region Public Health, Lyme Disease and Other Tick-Borne Diseases (page as of May 2026)
Halton Region Public Health tested 112 blacklegged ticks in its 2024 tick surveillance, and 30 were positive for Borrelia burgdorferi.Source: Halton Region Public Health, Lyme Disease and Other Tick-Borne Diseases (page as of May 2026)
The share of ticks from Halton Region's active surveillance testing positive for the Lyme disease bacterium rose from 17% in 2023 to 27% in 2024, and ticks collected in spring 2025 showed a further increase to 38%.Source: Halton Region Public Health, West Nile virus, Lyme disease and Anaplasma are active (physician update) (July 2025)
Halton Region recorded 28 confirmed locally acquired Lyme disease cases in 2023, up from 8 confirmed cases in 2022.Source: Halton Region Public Health, Increasing risk of tick-borne diseases in Halton (physician update) (May 2024)
Halton Region Public Health said in 2024 that the risk of acquiring Lyme disease in Halton remains low, though locally acquired cases are trending upward.Source: Halton Region Public Health, Increasing risk of tick-borne diseases in Halton (physician update) (May 2024)
In spring 2025, two ticks collected through Halton Region's active tick surveillance tested positive for Anaplasma for the first time in the region.Source: Halton Region Public Health, West Nile virus, Lyme disease and Anaplasma are active (physician update) (July 2025)

Are there blacklegged ticks in Toronto and Peel?

Yes. All of Toronto is considered an estimated blacklegged tick risk area, and Toronto Public Health's 2025 tick dragging found ticks carrying the Lyme disease bacterium in Rouge Park and at Highland Creek. Peel Public Health reports that blacklegged ticks are established in Peel Region.

All of Toronto is considered an estimated blacklegged tick risk area, according to Public Health Ontario's 2024 established risk areas map.Source: Toronto Public Health, Lyme Disease (accessed October 2026)
Toronto Public Health tested 133 blacklegged ticks from its fall 2025 tick dragging for six pathogens, and 36 tested positive for Borrelia burgdorferi only; ticks that also carried a second pathogen are listed separately by Toronto Public Health.Source: Toronto Public Health, Blacklegged Tick Surveillance (February 2026)
Toronto Public Health tested 57 blacklegged ticks from its fall 2024 tick dragging, and 22 tested positive for Borrelia burgdorferi only; ticks that also carried a second pathogen are listed separately by Toronto Public Health.Source: Toronto Public Health, Blacklegged Tick Surveillance (February 2026)
Toronto Public Health tested 121 blacklegged ticks from its fall 2023 tick dragging, and 38 tested positive for Borrelia burgdorferi only; ticks that also carried a second pathogen are listed separately by Toronto Public Health.Source: Toronto Public Health, Blacklegged Tick Surveillance (February 2026)
At the Glen Eagle Vista Trail in Rouge Park, Toronto Public Health's fall 2025 tick dragging found 31 adult blacklegged ticks: 15 tested positive for Borrelia burgdorferi only and 2 more for both Borrelia burgdorferi and Anaplasma phagocytophilum.Source: Toronto Public Health, Blacklegged Tick Surveillance (February 2026)
At Highland Creek, Toronto Public Health's fall 2025 tick dragging found 34 adult blacklegged ticks: 10 tested positive for Borrelia burgdorferi only and 1 more for both Borrelia burgdorferi and Babesia odocoilei.Source: Toronto Public Health, Blacklegged Tick Surveillance (February 2026)
In 2015, Toronto Public Health tick dragging in Rouge Park found 10 blacklegged ticks, and one tested positive for Borrelia burgdorferi.Source: Toronto Public Health, Blacklegged Tick Surveillance (February 2026)
Peel Public Health reports that blacklegged ticks are established in Peel Region and across most of southern Ontario.Source: Peel Public Health, Health Professionals Update: Tick-borne disease risk in Peel Region (October 2024)
Peel Region recorded 6 locally acquired tick-borne disease cases in 2021, 13 in 2022, 17 in 2023 and 18 in 2024 (as of October 9, 2024).Source: Peel Public Health, Health Professionals Update: Tick-borne disease risk in Peel Region (October 2024)

Where are Ontario's tick risk areas, and how fast are they spreading?

Most of Ontario's blacklegged tick risk areas are in southern Ontario along the north shores of Lake Erie, Lake Ontario and the St. Lawrence River, and Public Health Ontario added 13 new risk areas in 2025. A model estimate, supported by field data from eastern Ontario, puts the tick's northward spread at about 46 km per year.

Public Health Ontario's 2025 risk area map added 13 newly identified blacklegged tick risk areas in six public health units: three each in Renfrew and South East, two each in Middlesex-London, Peel and Waterloo, and one in Niagara.Source: Public Health Ontario, Public Health Ontario Launches New Ontario Vector-Borne Disease Tool (June 2025)
In 2025, most of Ontario's blacklegged tick risk areas were in southern Ontario along the north shores of Lake Erie, Lake Ontario and the St. Lawrence River, with more in the Northwestern and Thunder Bay health units.Source: Public Health Ontario, Public Health Ontario Launches New Ontario Vector-Borne Disease Tool (June 2025)
Public Health Ontario defines an established blacklegged tick risk area as a 20 km radius circle around the place where blacklegged ticks were found by tick dragging.Source: Public Health Ontario, Technical Notes: Ontario Vector-Borne Disease Tool (May 2026)
To confirm a risk area, Public Health Ontario uses three person-hours of tick dragging in spring (May) and fall (October); finding at least one blacklegged tick in both seasons means an established risk area.Source: Public Health Ontario, Technical Notes: Ontario Vector-Borne Disease Tool (May 2026)
Field data from eastern Ontario support a model estimate that the blacklegged tick's range is spreading north at 46 km per year, with expected variation of 35 to 55 km per year depending on temperature.Source: PLOS ONE (Clow KM et al.), Northward range expansion of Ixodes scapularis evident over a short timescale in Ontario, Canada (December 2017)
When 36 Ontario study sites were resampled in 2016, blacklegged ticks were found at 17 of them, including 5 sites where they had not been found in 2014 or 2015.Source: PLOS ONE (Clow KM et al.), Northward range expansion of Ixodes scapularis evident over a short timescale in Ontario, Canada (December 2017)
In 2017, Leeds, Grenville and Lanark had Ontario's highest Lyme disease incidence at 128.8 cases per 100,000, followed by Kingston, Frontenac and Lennox and Addington at 87.2.Source: Public Health Agency of Canada, Canada Communicable Disease Report, The continued rise of Lyme disease in Ontario, Canada: 2017 (October 2018)
In 2017, Hastings and Prince Edward Counties had a Lyme disease incidence of 28.6 cases per 100,000 and Ottawa had 18.1.Source: Public Health Agency of Canada, Canada Communicable Disease Report, The continued rise of Lyme disease in Ontario, Canada: 2017 (October 2018)
In 2017, the Leeds, Grenville and Lanark, Kingston, Frontenac and Lennox and Addington, and Ottawa health units held 9.7% of Ontario's population but reported 60.4% of its Lyme disease cases.Source: Public Health Agency of Canada, Canada Communicable Disease Report, The continued rise of Lyme disease in Ontario, Canada: 2017 (October 2018)

What share of Ontario's blacklegged ticks carry Lyme disease?

In 2022, 27.4% of the blacklegged ticks collected by tick dragging in Ontario tested positive for Borrelia burgdorferi, the bacterium that causes Lyme disease, down from 29.3% in 2021. Older figures from ticks the public sent in were measured differently and rose from 8.4% in 2008 to 19.1% in 2012.

In 2022, 27.4% of blacklegged ticks collected by tick dragging in Ontario tested positive for Borrelia burgdorferi, down from 29.3% in 2021.Source: Public Health Agency of Canada, Canada Communicable Disease Report, Surveillance for Ixodes scapularis and Ixodes pacificus ticks and their associated pathogens in Canada, 2022 (February 2026)
In 2022, 31.4% of blacklegged tick nymphs (70 of 223) and 26.1% of adult blacklegged ticks (176 of 674) collected by tick dragging in Ontario tested positive for Borrelia burgdorferi.Source: Public Health Agency of Canada, Canada Communicable Disease Report, Surveillance for Ixodes scapularis and Ixodes pacificus ticks and their associated pathogens in Canada, 2022 (February 2026)
The share of blacklegged ticks submitted in Ontario that carried Borrelia burgdorferi rose from 8.4% in 2008 to 19.1% in 2012.Source: PLOS ONE (Nelder MP et al.), Population-Based Passive Tick Surveillance and Detection of Expanding Foci of Blacklegged Ticks Ixodes scapularis and the Lyme Disease Agent Borrelia burgdorferi in Ontario, Canada (August 2014)
Of 17,230 blacklegged tick samples submitted from people in Ontario between 2011 and 2017, an estimated 17.5% carried Borrelia burgdorferi, with Toronto among the health units above 19.0%.Source: Parasites & Vectors (Nelder MP et al.), Monitoring the patterns of submission and presence of tick-borne pathogens in Ixodes scapularis collected from humans and companion animals in Ontario, Canada (2011-2017) (May 2021)
Between 2011 and 2017, 21.9% of unengorged blacklegged ticks submitted from people and pets in Ontario carried Borrelia burgdorferi, compared with 10.0% of engorged ticks.Source: Parasites & Vectors (Nelder MP et al.), Monitoring the patterns of submission and presence of tick-borne pathogens in Ixodes scapularis collected from humans and companion animals in Ontario, Canada (2011-2017) (May 2021)
In the Kingston, Frontenac and Lennox and Addington, Leeds, Grenville and Lanark, and Ottawa health units, the share of submitted ticks testing positive for Borrelia burgdorferi rose every year, from 12% in 2010 to 23% in 2016.Source: Emerging Infectious Diseases (Kulkarni MA et al.), Lyme Disease Emergence after Invasion of the Blacklegged Tick, Ixodes scapularis, Ontario, Canada, 2010-2016 (February 2019)
In Canada, infection with the Lyme disease bacterium in blacklegged ticks varies by region but is usually greater than 15% and sometimes over 50%.Source: Canadian Veterinary Journal (Bouchard C et al.), The increasing risk of Lyme disease in Canada (July 2015)
Since September 20, 2021, ticks submitted by the public in Ontario are no longer tested for pathogens, so newer tick testing results in Public Health Ontario's Vector-Borne Disease Tool come from tick dragging only.Source: Public Health Ontario, Technical Notes: Ontario Vector-Borne Disease Tool (May 2026)

How many ticks are found in Ontario, and which kinds?

Public Health Ontario reports 43 tick species recorded in Ontario. In passive surveillance data from 2008 to 2012, blacklegged ticks made up about 55% of the ticks the public submitted and American dog ticks about 36%. In 2022, Ontario recorded 4,338 blacklegged ticks through public submissions.

Public Health Ontario reports 43 tick species recorded in Ontario: 12 established, 17 adventive and 14 travel-related.Source: Public Health Ontario, The Ticks of Ontario (2nd edition) (March 2026)
In Ontario passive surveillance data from 2008 to 2012, blacklegged ticks made up about 55% of submitted ticks and American dog ticks about 36%.Source: Public Health Ontario, The Ticks of Ontario (2nd edition) (March 2026)
The groundhog tick is the third most common tick submitted from people in Ontario, at about 6% of submissions.Source: Public Health Ontario, The Ticks of Ontario (2nd edition) (March 2026)
Passive surveillance in Ontario recorded 4,338 blacklegged ticks in 2022: 2,211 submitted as physical specimens and 2,127 as photos through eTick.Source: Public Health Agency of Canada, Canada Communicable Disease Report, Surveillance for Ixodes scapularis and Ixodes pacificus ticks and their associated pathogens in Canada, 2022 (February 2026)
Ontario, Quebec and Nova Scotia together accounted for 83.4% of the blacklegged and western blacklegged ticks submitted through passive surveillance in Canada in 2022.Source: Public Health Agency of Canada, Canada Communicable Disease Report, Surveillance for Ixodes scapularis and Ixodes pacificus ticks and their associated pathogens in Canada, 2022 (February 2026)
Tick dragging at 95 Ontario sites collected 904 blacklegged ticks in 2022, the second highest provincial total in Canada after Quebec at 1,077.Source: Public Health Agency of Canada, Canada Communicable Disease Report, Surveillance for Ixodes scapularis and Ixodes pacificus ticks and their associated pathogens in Canada, 2022 (February 2026)
Between 2011 and 2017, the number of blacklegged tick samples submitted from people in Ontario each year ranged from 1,520 to 5,099, with submissions increasing over the period.Source: Parasites & Vectors (Nelder MP et al.), Monitoring the patterns of submission and presence of tick-borne pathogens in Ixodes scapularis collected from humans and companion animals in Ontario, Canada (2011-2017) (May 2021)
Members of the public in Ontario submitted 14,369 ticks of 18 species from 2008 to 2012, and four species (blacklegged, American dog, groundhog and lone star ticks) made up 98.1% of them.Source: PLOS ONE (Nelder MP et al.), Population-Based Passive Tick Surveillance and Detection of Expanding Foci of Blacklegged Ticks Ixodes scapularis and the Lyme Disease Agent Borrelia burgdorferi in Ontario, Canada (August 2014)
The annual median number of lone star ticks submitted to the Public Health Ontario laboratory rose from 24 in 1999 to 2004 to 78.0 in 2017 to 2019, then fell to 15.5 in 2020 to 2023, when overall tick submissions decreased.Source: Public Health Ontario, Hazard Identification and Risk Assessment: Climate Change and Vector-borne Diseases (May 2026)
Fewer than 20 brown dog ticks are submitted per year through passive surveillance in Ontario.Source: Public Health Ontario, Hazard Identification and Risk Assessment: Climate Change and Vector-borne Diseases (May 2026)
Blacklegged tick nymphs are 0.15 cm long before feeding and about 0.3 cm when fully fed; adult females are about 0.3 cm before feeding and about 1 cm when fully fed.Source: Health Canada, Blacklegged (deer) ticks (December 2016)

When is tick season in Ontario?

Ticks typically start looking for a host once air temperatures reach 4 to 10 degrees Celsius, and more than 80% of cases of Ontario's four reportable tick-borne diseases begin between May and October.

Ticks typically begin questing for a host when air temperatures reach 4 to 10 degrees Celsius.Source: Public Health Agency of Canada, Canada Communicable Disease Report, Increased risk of tick-borne diseases with climate and environmental changes (April 2019)
More than 80% of cases of Ontario's four reportable tick-borne diseases have onset dates between May and October.Source: Public Health Ontario, Tick-Borne Diseases in Ontario: An Update (PHO Rounds) (May 2026)
Of Canada's 2024 Lyme disease cases with a known symptom onset date, 28% began in June, 26% in July and 13% in August.Source: Public Health Agency of Canada, Annual report: Tick-borne disease surveillance in Canada (January 2026)
In 2023, 31 of Ontario's 40 anaplasmosis cases (78%) and all 15 babesiosis cases had an estimated illness onset from June to August.Source: Public Health Ontario, Enhanced Epidemiological Summary: Anaplasmosis and Babesiosis in Ontario: 2023 (May 2024)

Who gets Lyme disease in Ontario?

Lyme disease in Ontario is reported more often in males than females. Incidence is highest in adults aged 60 to 69, with a second peak in children aged 5 to 9.

Males made up 58% and females 42% of confirmed and probable Lyme disease cases reported in Ontario from 2023 to 2025.Source: Public Health Ontario, Tick-Borne Diseases in Ontario: An Update (PHO Rounds) (May 2026)
The median age of Ontario Lyme disease patients from 2015 to 2022 was 53.0 years, and people aged 60 to 69 were the largest age group at 21.1% of cases.Source: Emerging Infectious Diseases (Adams JA, Nelder MP et al.), Age- and Sex-Specific Differences in Lyme Disease Health-Related Behaviors, Ontario, Canada, 2015-2022 (October 2024)
From 2015 to 2022, Ontario's average annual Lyme disease incidence was highest among adults aged 60 to 69, at 11.8 per 100,000, with a separate peak among children aged 5 to 9, at 7.2 per 100,000.Source: Emerging Infectious Diseases (Adams JA, Nelder MP et al.), Age- and Sex-Specific Differences in Lyme Disease Health-Related Behaviors, Ontario, Canada, 2015-2022 (October 2024)
Males made up 56% of Canada's reported Lyme disease cases in 2024 and females 44%.Source: Public Health Agency of Canada, Annual report: Tick-borne disease surveillance in Canada (January 2026)
In 2024, a larger share of Canada's Lyme disease cases were among people aged 5 to 9 (7%) and 60 to 69 (23%) than in other age groups.Source: Public Health Agency of Canada, Annual report: Tick-borne disease surveillance in Canada (January 2026)
About 3% of Canada's reported Lyme disease cases in 2024 were likely acquired during travel outside Canada.Source: Public Health Agency of Canada, Annual report: Tick-borne disease surveillance in Canada (January 2026)

How long must a tick be attached to pass on Lyme disease?

In most cases an infected tick must be attached for at least 24 hours to pass on the Lyme disease bacterium, and the incubation period for early localized Lyme disease is 3 to 30 days. Powassan virus can pass much faster, within 15 to 30 minutes of attachment.

In most cases, an infected tick must be attached for at least 24 hours before it passes on the Lyme disease bacterium.Source: Public Health Agency of Canada, Lyme disease: For health professionals (July 2026)
Powassan virus can be transmitted within 15 to 30 minutes of tick attachment.Source: Public Health Agency of Canada, Canada Communicable Disease Report, Increased risk of tick-borne diseases with climate and environmental changes (April 2019)
Halton Region Public Health says that if a tick is attached to your skin for less than 24 hours, your chance of getting Lyme disease is extremely low, and advises removing an attached tick as soon as possible.Source: Halton Region Public Health, Lyme Disease and Other Tick-Borne Diseases (page as of May 2026)
The incubation period for early localized Lyme disease is 3 to 30 days.Source: Public Health Agency of Canada, Lyme disease: For health professionals (July 2026)
The erythema migrans rash usually appears within 7 days of the tick bite but can appear anywhere from 3 to 30 days after it.Source: Public Health Agency of Canada, Lyme disease: For health professionals (July 2026)
The erythema migrans rash of Lyme disease slowly grows to more than 5 cm across over several days.Source: Public Health Agency of Canada, Lyme disease: Symptoms and treatment (July 2026)
Among locally acquired Lyme disease cases in Canada from 2009 to 2019 with clinical information, 75.1% had a single erythema migrans rash and 34.1% had arthritis.Source: Public Health Agency of Canada, Canada Communicable Disease Report, Surveillance for Lyme disease in Canada, 2009 to 2019 (May 2022)
In the same cases, heart problems were reported in 3.7%, Bell's palsy in 7.6% and other nerve-related problems in 19.0%.Source: Public Health Agency of Canada, Canada Communicable Disease Report, Surveillance for Lyme disease in Canada, 2009 to 2019 (May 2022)
Symptoms of anaplasmosis typically begin 7 to 21 days after a bite from an infected blacklegged tick, and symptoms of babesiosis and Powassan virus 7 to 30 days after.Source: Government of Ontario, Tick-borne diseases (February 2026)

How common are anaplasmosis, babesiosis and Powassan virus in Ontario?

Anaplasmosis, babesiosis and Powassan virus became reportable in Ontario on July 1, 2023, so 2023 is a partial year: Ontario reported 40 anaplasmosis cases, 15 babesiosis cases and no Powassan virus cases. From 2023 to 2025, 112 of Ontario's confirmed and probable anaplasmosis cases were hospitalized and 4 died.

On July 1, 2023, the Ontario Ministry of Health made anaplasmosis, babesiosis and Powassan virus three new tick-borne Diseases of Public Health Significance.Source: Public Health Ontario, Enhanced Epidemiological Summary: Anaplasmosis and Babesiosis in Ontario: 2023 (May 2024)
Ontario reported 40 cases of anaplasmosis in 2023 (17 confirmed and 23 probable) and 15 cases of babesiosis (8 confirmed and 7 probable). 2023 is a partial year: the diseases became reportable on July 1, 2023.Source: Public Health Ontario, Enhanced Epidemiological Summary: Anaplasmosis and Babesiosis in Ontario: 2023 (May 2024)
Ontario reported no probable or confirmed cases of Powassan virus disease in 2023.Source: Public Health Ontario, Enhanced Epidemiological Summary: Anaplasmosis and Babesiosis in Ontario: 2023 (May 2024)
A May 2026 Public Health Ontario Rounds presentation reports that anaplasmosis incidence in Ontario has increased in the three years since it became reportable.Source: Public Health Ontario, Tick-Borne Diseases in Ontario: An Update (PHO Rounds) (May 2026)
Ontario recorded 112 hospitalizations (21.1% of cases) and 4 deaths among confirmed and probable anaplasmosis cases from January 1, 2023 to December 31, 2025.Source: Public Health Ontario, Tick-Borne Diseases in Ontario: An Update (PHO Rounds) (May 2026)
Ontario recorded 10 hospitalizations (37.0% of cases) and no deaths among babesiosis cases from 2023 to 2025.Source: Public Health Ontario, Tick-Borne Diseases in Ontario: An Update (PHO Rounds) (May 2026)
Ontario recorded 5 hospitalizations (71.4% of cases) and 1 death among Powassan virus cases from 2023 to 2025.Source: Public Health Ontario, Tick-Borne Diseases in Ontario: An Update (PHO Rounds) (May 2026)
Of the 30 Ontario anaplasmosis cases in 2023 with an exposure location in Ontario, all of their reported Ontario exposure locations were in eastern Ontario, most often Kingston, Frontenac and Lennox and Addington (13 cases).Source: Public Health Ontario, Enhanced Epidemiological Summary: Anaplasmosis and Babesiosis in Ontario: 2023 (May 2024)
In 2023, one Ontario babesiosis case named Halton Region as an exposure location and two named Toronto.Source: Public Health Ontario, Enhanced Epidemiological Summary: Anaplasmosis and Babesiosis in Ontario: 2023 (May 2024)
In 2023, adults aged 60 and older made up 73% of Ontario's anaplasmosis cases and 53% of its babesiosis cases.Source: Public Health Ontario, Enhanced Epidemiological Summary: Anaplasmosis and Babesiosis in Ontario: 2023 (May 2024)
Anaplasmosis, babesiosis and Powassan virus disease became nationally notifiable in Canada in January 2024.Source: Public Health Agency of Canada, Annual report: Tick-borne disease surveillance in Canada (January 2026)
Canada reported 673 cases of anaplasmosis in 2024, an incidence of 1.63 per 100,000 population, and Ontario accounted for 24% of them, second to Nova Scotia at 69%.Source: Public Health Agency of Canada, Annual report: Tick-borne disease surveillance in Canada (January 2026)
Canada reported 10 cases of babesiosis in 2024, with Ontario reporting the most of any province, and 3 cases of Powassan virus disease, all in Quebec and Ontario.Source: Public Health Agency of Canada, Annual report: Tick-borne disease surveillance in Canada (January 2026)
In 2024, 23 Ottawa residents were reported with anaplasmosis, 1 with babesiosis and none with Powassan virus.Source: Ottawa Public Health, Climate Change and Public Health in Ottawa: 2025 Surveillance Report, Key Findings (November 2025)
The Public Health Agency of Canada reports that death from anaplasmosis is rare, with a case fatality rate of less than 1%.Source: Public Health Agency of Canada, Anaplasmosis: For health professionals (July 2026)
In severe Powassan virus disease the case fatality rate is 5 to 10%, and about 50% of survivors may have long-term health problems.Source: Public Health Ontario, Tick-Borne Diseases in Ontario: An Update (PHO Rounds) (May 2026)
Halton Region Public Health says most people infected with Powassan virus develop very mild, flu-like symptoms or no symptoms at all.Source: Halton Region Public Health, Lyme Disease and Other Tick-Borne Diseases (page as of May 2026)
The first Powassan virus case was reported in 1958, in a young boy in Powassan, Ontario, and Canada had 22 reported cases as of 2018.Source: Public Health Agency of Canada, Pathogen Safety Data Sheet: Powassan encephalitis virus (December 2023)

The 2023 Ontario counts above come from Public Health Ontario and cover a partial year, while the 2024 counts for Canada come from federal surveillance, so the two are not directly comparable.

What other germs do Ontario ticks carry?

Besides the Lyme disease bacterium, Ontario blacklegged ticks can carry Anaplasma phagocytophilum, Babesia odocoilei and Borrelia miyamotoi (no Babesia microti was found in 2022 tick dragging), and in 2025 the bacterium that causes Rocky Mountain spotted fever was found in American dog ticks at Long Point.

In 2022, 3.8% of blacklegged ticks collected by tick dragging in Ontario (34 of 899) tested positive for Anaplasma phagocytophilum, the cause of anaplasmosis.Source: Public Health Agency of Canada, Canada Communicable Disease Report, Surveillance for Ixodes scapularis and Ixodes pacificus ticks and their associated pathogens in Canada, 2022 (February 2026)
In 2022, 5.6% of dragged blacklegged ticks in Ontario (50 of 899) tested positive for Babesia odocoilei, and 0.3% (3 of 899) for Borrelia miyamotoi.Source: Public Health Agency of Canada, Canada Communicable Disease Report, Surveillance for Ixodes scapularis and Ixodes pacificus ticks and their associated pathogens in Canada, 2022 (February 2026)
No blacklegged ticks dragged in Ontario in 2022 tested positive for Babesia microti (0 of 899) or Powassan virus (0 of 895).Source: Public Health Agency of Canada, Canada Communicable Disease Report, Surveillance for Ixodes scapularis and Ixodes pacificus ticks and their associated pathogens in Canada, 2022 (February 2026)
Among blacklegged ticks submitted from people in Ontario, 0.43% carried Anaplasma phagocytophilum (2011 to 2017), 0.35% carried Borrelia miyamotoi (2014 to 2017) and 0.054% carried Babesia microti (2013 to 2017), the last highest in Peel and Hamilton.Source: Parasites & Vectors (Nelder MP et al.), Monitoring the patterns of submission and presence of tick-borne pathogens in Ixodes scapularis collected from humans and companion animals in Ontario, Canada (2011-2017) (May 2021)
Anaplasma phagocytophilum was found in 1.1% of blacklegged ticks submitted through passive surveillance in Canada in 2021.Source: Public Health Agency of Canada, Canada Communicable Disease Report, Surveillance for Ixodes scapularis and Ixodes pacificus ticks and their associated pathogens in Canada, 2021 (February 2026)
In 2025, Rickettsia rickettsii, the bacterium that causes Rocky Mountain spotted fever, was found in American dog ticks at Long Point, Ontario, the first such detection in the province in over 50 years.Source: Public Health Ontario, Hazard Identification and Risk Assessment: Climate Change and Vector-borne Diseases (May 2026)
A September 2025 memo from the Office of Ontario's Chief Medical Officer of Health reported two confirmed human cases of Rocky Mountain spotted fever in Ontario, both with exposures at Long Point.Source: Ontario Ministry of Health, Office of the Chief Medical Officer of Health, Memorandum: Rocky Mountain Spotted Fever Exposures at Long Point, ON (September 2025)
Halton Region Public Health says the risk of getting anaplasmosis, babesiosis, Powassan virus or Rocky Mountain spotted fever remains low in Ontario, including Halton Region.Source: Halton Region Public Health, Lyme Disease and Other Tick-Borne Diseases (page as of May 2026)

How We Collected These Numbers

We only use primary sources: government public health agencies, Ontario public health units, and peer-reviewed studies. News stories and other statistics pages are never cited in place of the original source.

Every number was checked on its source page or PDF in a separate review before it was added, and it is copied as published. Agencies sometimes count the same year differently, for example by the date the data was pulled or the case definition used, so where two sources disagree we show each with its own source instead of blending them. Preliminary counts are marked as preliminary. Halton Region's website blocks automated readers, so we read Halton's tick surveillance page from the Internet Archive copy dated May 10, 2026; the link goes to Halton's own page, which may now show newer results.

Two figures are our own arithmetic on Halton Region's 2025 table, and both are labelled: the Oakville total, which adds up the four Oakville sites where Halton found blacklegged ticks, and the count of sites in the Halton table.

The date at the top is when this page was last updated. Each source shows its own publication date.

Sources

Public Health Agency of Canada, Annual report: Tick-borne disease surveillance in Canada (January 2026)
Public Health Agency of Canada, Lyme disease: Monitoring (July 2026)
Halton Region Public Health, Lyme Disease and Other Tick-Borne Diseases (page as of May 2026)
Halton Region Public Health, West Nile virus, Lyme disease and Anaplasma are active (physician update) (July 2025)
Toronto Public Health, Lyme Disease (accessed October 2026)
Public Health Ontario, Public Health Ontario Launches New Ontario Vector-Borne Disease Tool (June 2025)
Public Health Agency of Canada, Canada Communicable Disease Report, Surveillance for Ixodes scapularis and Ixodes pacificus ticks and their associated pathogens in Canada, 2022 (February 2026)
Public Health Ontario, Tick-Borne Diseases in Ontario: An Update (PHO Rounds) (May 2026)
Public Health Agency of Canada, Lyme disease: For health professionals (July 2026)
Public Health Ontario, Hazard Identification and Risk Assessment: Climate Change and Vector-borne Diseases (May 2026)
Public Health Agency of Canada, Lyme disease surveillance in Canada: Annual edition 2022 (April 2024)
Emerging Infectious Diseases (Adams JA, Nelder MP et al.), Age- and Sex-Specific Differences in Lyme Disease Health-Related Behaviors, Ontario, Canada, 2015-2022 (October 2024)
Public Health Agency of Canada, Canada Communicable Disease Report, Surveillance for Lyme disease in Canada, 2009 to 2019 (May 2022)
Canadian Veterinary Journal (Bouchard C et al.), The increasing risk of Lyme disease in Canada (July 2015)
Halton Region Public Health, Increasing risk of tick-borne diseases in Halton (physician update) (May 2024)
Toronto Public Health, Blacklegged Tick Surveillance (February 2026)
Peel Public Health, Health Professionals Update: Tick-borne disease risk in Peel Region (October 2024)
Public Health Ontario, Technical Notes: Ontario Vector-Borne Disease Tool (May 2026)
PLOS ONE (Clow KM et al.), Northward range expansion of Ixodes scapularis evident over a short timescale in Ontario, Canada (December 2017)
Public Health Agency of Canada, Canada Communicable Disease Report, The continued rise of Lyme disease in Ontario, Canada: 2017 (October 2018)
PLOS ONE (Nelder MP et al.), Population-Based Passive Tick Surveillance and Detection of Expanding Foci of Blacklegged Ticks Ixodes scapularis and the Lyme Disease Agent Borrelia burgdorferi in Ontario, Canada (August 2014)
Parasites & Vectors (Nelder MP et al.), Monitoring the patterns of submission and presence of tick-borne pathogens in Ixodes scapularis collected from humans and companion animals in Ontario, Canada (2011-2017) (May 2021)
Emerging Infectious Diseases (Kulkarni MA et al.), Lyme Disease Emergence after Invasion of the Blacklegged Tick, Ixodes scapularis, Ontario, Canada, 2010-2016 (February 2019)
Public Health Ontario, The Ticks of Ontario (2nd edition) (March 2026)
Health Canada, Blacklegged (deer) ticks (December 2016)
Public Health Agency of Canada, Canada Communicable Disease Report, Increased risk of tick-borne diseases with climate and environmental changes (April 2019)
Public Health Ontario, Enhanced Epidemiological Summary: Anaplasmosis and Babesiosis in Ontario: 2023 (May 2024)
Public Health Agency of Canada, Lyme disease: Symptoms and treatment (July 2026)
Government of Ontario, Tick-borne diseases (February 2026)
Ottawa Public Health, Climate Change and Public Health in Ottawa: 2025 Surveillance Report, Key Findings (November 2025)
Public Health Agency of Canada, Anaplasmosis: For health professionals (July 2026)
Public Health Agency of Canada, Pathogen Safety Data Sheet: Powassan encephalitis virus (December 2023)
Public Health Agency of Canada, Canada Communicable Disease Report, Surveillance for Ixodes scapularis and Ixodes pacificus ticks and their associated pathogens in Canada, 2021 (February 2026)
Ontario Ministry of Health, Office of the Chief Medical Officer of Health, Memorandum: Rocky Mountain Spotted Fever Exposures at Long Point, ON (September 2025)

How to Cite This Page

You are welcome to quote these numbers. Please credit the original source shown under each one, and link to this page:

Sting Out Pest Control. (2026, October 21). Ontario Tick and Lyme Disease Statistics 2026. https://www.stingoutpestcontrol.com/ontario-tick-statistics

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<a href="https://www.stingoutpestcontrol.com/ontario-tick-statistics">Ontario Tick and Lyme Disease Statistics 2026</a> (Sting Out Pest Control, updated October 21, 2026)

Charts and tables on this page can be reused too, with credit to Sting Out Pest Control, a link to this page and the original source named with each one.

This page summarizes public data and is not medical advice. Halton Region Public Health advises removing an attached tick as soon as possible and talking to a health care provider or pharmacist. If you develop symptoms, see a health care provider right away or call Health811 at 811.

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