Vector and Animal-Borne Disease Information for Health Care Providers

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The information on this page is for health professionals. If you are looking for health information for community members visit Insect and Animal Diseases.

Vector-borne diseases

Vector-borne diseases that must be reported to Public Health include,

Lyme disease, babesiosis, anaplasmosis and Powassan virus, all transmitted by blacklegged ticks
West Nile virus, transmitted by mosquitoes

Refer to the list of Diseases of Public Health Significance for how to report to Public Health.

As of September 2025, health care providers are strongly encouraged to report all suspected and confirmed cases of Rocky Mountain Spotted Fever (RMSF) to their local public health unit. Contact the Infectious Disease and Tuberculosis Control Program by the next business day (Phone: 519-575-4400 ext. 5275, Fax: 519-883-2248).

Primary resources

Vector-borne and zoonotic diseases (Public Health Ontario)
Tick-borne diseases (Government of Ontario)

Additional resources

Ontario vector-borne disease tool (Public Health Ontario) includes blacklegged tick risk map, surveillance data of human cases and vector populations, updated annually
Lyme disease monitoring in Canada (Government of Canada)
Tick-borne diseases (Government of Canada)
Lyme disease surveillance and data in the USA (CDC)
eTick.ca, a free platform to submit a picture for tick identification. Results are available within 1-2 business days, may be as soon as 2-3 hours during business hours.
Presentation on Tick-borne Disease (Public Health Ontario) May, 2024

Testing for vector-borne diseases

Testing for vector-borne diseases is performed at the Public Health Ontario laboratory.

Lyme disease testing
- As of April 2023, Public Health Ontario is testing for Lyme disease using a modified two-tiered testing (MTTT) algorithm
- Although MTTT improves sensitivity during early localized disease, management of patients should be based on the overall clinical picture present. This is due to the possibility of false negatives in serological results early in the disease’s course.
- Sensitivity may be reduced if already treated.
- MTTT serum antibodies cannot distinguish between a past or new case of Lyme disease, so correlation with clinical symptoms and risk acquisition is important.
- MTTT serum antibodies usually remain positive long-term even after successful treatment (so test of cure is not advised).
- Serology is not required for public health reporting for clinician-confirmed erythema migrans of > 5 cm.
Babesiosis testing
Anaplasmosis testing
Powassan virus testing
West Nile virus testing
Rocky Mountain Spotted Fever (RMSF) testing

Treatment and clinical guidance

Lyme disease

Doxycycline is the preferred antibiotic treatment for early Lyme disease in both children and adults.
Management of Tick Bites and Investigation of Early Localized Lyme Disease (Ontario Clinical Guidance)
Assessment and prescribing algorithm for pharmacists: Antibiotic prophylaxis to prevent Lyme disease following a tick bite (Public Health Ontario)
Lyme disease clinical practice guidelines (Infectious Diseases Society of America)

Other reportable tick-borne diseases

Babesiosis treatment (CDC)
Anaplasmosis treatment (CDC)
Anaplasmosis guidance (National Collaborating Centre for Infectious Diseases)
Powassan virus treatment and prevention (CDC)
Powassan virus symptoms and treatment (Government of Canada)

Rocky Mountain Spotted Fever (RMSF)

There have been confirmed cases of RMSF in humans and dogs in Ontario. All exposures were at Long Point, Ontario. RMSF is caused by the bacterium R. Rickettsia and is transmitted by the American dog tick (Dermacentor variabilis), a common tick species in Ontario.

RMSF symptoms usually appear within 2 to 14 days after a tick bite and may include fever, headache, rash, nausea, vomiting, muscle pain and abdominal pain. The rash typically starts as a maculopapular rash on the wrists, forearms and ankles, then spreads to the trunk and becomes petechial over time. The characteristic rash may be absent or delayed and illness can progress rapidly.

Prompt recognition and treatment are critical to prevent severe outcomes. Diagnosis is primarily clinical, and treatment with doxycycline should not be delayed while awaiting lab confirmation.

For information on testing, please visit Public Health Ontario’s testing information page.

RMSF is not currently listed as a Disease of Public Health Significance. Health care providers are strongly encouraged to report all cases to their local public health unit. This will help support surveillance efforts and provide valuable information about the risk of transmission in Ontario.

Contact the Infectious Disease and Tuberculosis Control Program by the next business day to report cases of RMSF (Phone: 519-575-4400 ext. 5275, Fax: 519-883-2248).