- Case counts (2016-2025), population estimates (2016-2023), & population projections (2024-2025): Public Health Ontario.
- Query: Case counts of reportable diseases by public health unit and year. Toronto, ON: Ontario Agency for Health Protection and Promotion; extracted on March 9, 2026.
Anaplasmosis
Anaplasmosis (previously known as human granulocytic anaplasmosis or HGA) is a disease caused by the bacterium Anaplasma phagocytophilum. These bacteria are spread to people by tick bites primarily from the blacklegged tick, also called a deer tick (Ixodes scapularis), and the western blacklegged tick (Ixodes pacificus). These ticks are in our region and are also spreading to new areas of the province, sometimes travelling on birds and deer. See Public Health Ontario's Vector-Borne Disease Tool.
Ticks are most active in spring and summer but can be found at any time of the year when the temperature is above freezing (0oC). As we experience global warming, ticks are becoming a greater concern.
Infections brought on by blacklegged tick bites, including Lyme disease, anaplasmosis, babesiosis, and Powassan virus, can be serious. Not all blacklegged ticks carry the infectious agents that cause infections, and not everyone who is bitten by an infected tick will develop signs and symptoms of these diseases.
See the Ministry of Health’s Tick-Borne Diseases webpage for information about:
- What blacklegged ticks look like and where they live
- How to avoid getting a tick bite and how to remove a tick
- Tick testing
- Signs and symptoms, diagnosis, and treatment
The Public Health Agency also has information about how to remove a tick and how to prevent tick bites.
Found a tick on you?
If you find a tick on you or someone else, place it in a container and get it identified on eTick.ca. If you find a tick on your pet, call your veterinary clinic. Laboratory testing is for surveillance purposes only and is not intended to replace clinical guidance.
Visit your healthcare provider as soon as possible if you are not comfortable with removing a tick, you cannot remove the tick because it has buried itself deep into your skin, or if you have concerns after being bitten by a tick, aren’t feeling well, or have any symptoms.
Contact our Environmental Health program for more information. They can be reached at 705-474-1400 or toll-free at 1-800-563-2808, ext. 5400.
Know Your Tick.
Submit a photo of your tick and find out its species within 48 hours on eTick.ca.
Local Information
2025 Statistics
Incidence rate is the number of new cases of disease divided by the number of persons at risk for the disease during a particular time period.
Cases
0*
Incidence rate per 100,000 in 2025: 0
*Includes confirmed cases in 2025.
Incidence rate per 100,000 of anaplasmosis by year
More Information about Anaplasmosis
- National Collaborating Centre for Infectious Diseases: Anaplasmosis
- See our Lyme Disease webpage for more information about tick prevention, management, and safety.
Report to the Health Unit within one business day by fax (705-482-0670) or phone at 705-474-1400 or toll free at 1-800-563-2808, ext. 5229 if anaplasmosis is suspected or confirmed as per Ontario Regulation 135/18 and amendments under the Health Protection and Promotion Act, R.S.O., c.H.7.
Should one go to childcare, school, or work if they have anaplasmosis?
No exclusion necessary unless too ill to participate in regular activities. Person to person transmission has not been documented.
Healthcare Provider Information
Individuals with potential exposure (prolonged hard tick bite in endemic area) and compatible clinical signs/symptoms (acute onset of fever accompanied by chills, headache, myalgia, arthralgia, leukopenia, thrombocytopenia, and/or elevated liver enzymes) may have testing requested for Anaplasma.
Samples to collect for individuals being investigated for anapasmosis include:
- Within two weeks of sign(s)/symptom(s) onset (i.e. acute illness) the following may be collected:
- whole blood or serum specimen for PCR
- first serum specimen (will be stored for future paired serology)
- Between 2 to 12 weeks from sign(s)/symptom(s) onset (i.e. convalescent phase) if the initial PCR during acute illness was negative:
- second serum specimen for paired serology (not advised if PCR was positive)
- For PCR - specimens should ideally be collected in acute illness prior to the initiation of antibiotic therapy, but treatment should never be withheld, if required based on the patient's clinical status.
- For serology - an acute serum (within two weeks of sign(s)/symptom(s) onset) and a convalescent serum (between 2-12 weeks form sign(s)/symptom(s) onset) is required for testing to be performed.
For additional information and instruction on specimen collection, refer to Public Health Ontario Lab’s (PHOL) Test Information Sheet on Anaplasma – PCR and Serology
While waiting for laboratory testing, initiate treatment with appropriate antibiotics for patients who present with clinical manifestations of anaplasmosis or other rickettsial disease.
Doxycycline is the most commonly recommended oral antibiotic for symptomatic adult and pediatric patients suspected of having anaplasmosis. Rifampin is another alternative.
Doxycycline is also the preferred treatment for other tick-borne diseases. However, doxycycline and other drugs used to treat anaplasmosis are not effective against babesiosis. If infection or co-infection with babesiosis is suspected or confirmed, a specific regimen is required.
- Public Health Ontario: Anaplasmosis
- Public Health Ontario: Arthropods (e.g., Mites, Lice, Fleas, Maggots, and Ticks) - Microscopy
- Public Health Ontario: Enhanced Epidemiological Summary: Anaplasmosis and Babesiosis in Ontario: 2023
- Infectious Disease Protocol, Appendix 1: Anaplasmosis
- Public Agency of Canada: Anaplasmosis: For Health Professionals
- National Collaborating Centre for Infectious Diseases: A review of ticks in Canada and health risks from exposure
Contact our Communicable Disease Control (CDC) program at 705-474-1400 or toll free at 1-800-563-2808, ext. 5229, or by email to cdc@healthunit.ca for more information.
Last updated: Feb 2026, by CDC