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!   Symptoms & response   !

What ticks can do.
And what to do about it.

Most tick bites in Canada are uneventful. The risk of serious disease is real but specific — concentrated in the blacklegged tick’s range, in attached ticks engorged for 24+ hours, and in a handful of identifiable diseases. Below is what to watch for, and where to go if it happens.

What's out there

Tick-borne diseases in Canada.

Lyme disease

moderate
Pathogen
Borrelia burgdorferi (bacterium)
Vector
Blacklegged tick (Ixodes scapularis), western blacklegged (I. pacificus)
Onset
3–30 days after bite (rash); weeks to months for systemic signs.

By far the most common tick-borne disease in Canada and the one most worth knowing the early signs of. Treatable with antibiotics in early stages. Late-stage Lyme is much harder to clear.

Symptoms

Expanding rash at the bite site (bullseye or solid red — most Canadian cases never produce a bullseye). Fever, fatigue, headache, muscle and joint aches, swollen lymph nodes. Later: arthritis (especially the knees), facial palsy, neurological symptoms.

Anaplasmosis

moderate
Pathogen
Anaplasma phagocytophilum (bacterium)
Vector
Blacklegged tick
Onset
1–2 weeks after bite.

Often a Lyme co-infection — the same blacklegged tick carries both. Treatable with doxycycline. Can be severe in older or immunocompromised patients.

Symptoms

High fever, severe headache, muscle aches, chills. Looks like a bad flu without respiratory symptoms. Lab tests show low platelets, low white-cell count, elevated liver enzymes.

Babesiosis

moderate
Pathogen
Babesia microti (protozoan)
Vector
Blacklegged tick
Onset
1–4 weeks after bite, occasionally longer.

Rare in Canada but increasing in the same geography as Lyme. Causes a malaria-like illness by infecting red blood cells. Can be severe in older or splenectomised patients.

Symptoms

Fever, fatigue, chills, sweats, muscle aches. Sometimes haemolytic anaemia (dark urine, jaundice). Often diagnosed alongside Lyme — symptoms overlap.

Powassan virus

severe
Pathogen
Powassan virus (flavivirus)
Vector
Blacklegged tick; also some Ixodes cookei
Onset
1 week to 1 month after bite.

Rare but very serious — there is no specific antiviral treatment. Mortality around 10%; long-term neurological deficits in up to half of survivors. Transmission can happen within minutesof attachment, unlike Lyme’s 24-hour window.

Symptoms

Fever, headache, vomiting, weakness, confusion. Can progress to seizures, encephalitis, meningitis. Go to an emergency room if these neuro symptoms appear in the month after a tick bite.

Ehrlichiosis

moderate
Pathogen
Ehrlichia chaffeensis, E. muris eauclairensis
Vector
Lone star tick, blacklegged tick
Onset
1–2 weeks after bite.

Rare in Canada but rising as the lone star tick establishes in southern Ontario. Similar presentation to anaplasmosis. Treatable with doxycycline.

Symptoms

Fever, headache, fatigue, muscle aches, sometimes a rash. Low platelets and elevated liver enzymes on lab work.

Rocky Mountain spotted fever

severe
Pathogen
Rickettsia rickettsii (bacterium)
Vector
American dog tick, Rocky Mountain wood tick
Onset
2–14 days after bite.

Very rare in Canada (mostly south of the border). When it does occur it can progress fast and is fatal in 15-30% of untreated cases. Treatable with doxycycline if caught early.

Symptoms

Sudden high fever, severe headache, muscle pain. A characteristic rash starting on wrists and ankles appears around day 3–5 — small red spots that may become petechial.

Alpha-gal syndrome

chronic
Pathogen
Alpha-gal allergen (not an infection)
Vector
Lone star tick
Onset
Weeks to months — develops after repeated bites.

Not an infection but an immune reaction to a carbohydrate (galactose-α-1,3-galactose) introduced by lone star tick saliva. Causes a delayed allergy to red meat — symptoms appear 3–8 hours after eating beef, pork, or lamb.

Symptoms

Hives, abdominal pain, nausea, or anaphylaxis several hours after a red-meat meal. The delay makes it hard to recognise. Diagnosed by IgE blood test.

Where to go

Pharmacist, doctor, or ER.

The right destination depends on what’s happening and when. Three tiers, in escalating order of urgency.

Pharmacist

When

Within 72 hours of a high-risk tick bite, no symptoms yet.

What

In Ontario: a pharmacist can prescribe a single preventive dose of doxycycline if criteria are met — deer tick, attached ≥24 hours, within 72 hours of removal, no allergy. Walk in with the tick on a card. See the removal page for full criteria. In other provinces this pathway varies — check with your local pharmacy regulator.

Walk-in clinic or family doctor

When

Symptoms appearing within 30 days of a bite.

What

Expanding rash (bullseye or solid red, anywhere on the body), unexplained fever, joint or muscle pain, severe fatigue, headaches that won’t quit, swollen lymph nodes. Bring the tick if you saved it. The earlier antibiotics start, the better the outcome.

Emergency room — call 911

When

Severe symptoms within a month of a bite.

What

Confusion, severe headache, neck stiffness, seizures, facial weakness on one side, sudden vision changes, difficulty breathing, anaphylaxis. These can be signs of Powassan virus encephalitis, late-disseminated Lyme, anaphylactic alpha-gal reaction, or other serious tick-borne illness. Don’t wait it out.

Tick testing

Two Canadian labs that test the tick itself.

Testing the tick is sometimes faster and more reliable than testing your blood, because the antibody response takes weeks to show up. If you saved the tick, two Canadian options:

Free

eTick.ca

A Canadian site (run by Bishop’s University) that identifies your tick from a photo. Free; usually back to you within a few days. Your submission also helps build the national tick-tracking map. etick.ca

Paid, PCR testing

Geneticks

Tests the tick itself by PCR for Borrelia (Lyme), Anaplasma, Babesia, Borrelia miyamotoi, and Powassan. Turnaround typically under a week. Cost varies by panel. geneticks.ca

A positive tick test means the tick carried a pathogen — not necessarily that it transmitted to you. A negative tick test is reassuring but not definitive. Treat the test result as one input alongside symptoms and exposure window, not as a yes/no answer.

Last reviewed

General information only — not medical advice. In an emergency, call 911. Read the full disclaimer.

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