Anaplasmosis, babesiosis, and Powassan virus must now be reported to Medical Officer of Health

Advisory Alert

June 30, 2023

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To: Local Health System Partners


Amendments to the Health Protection and Promotion Act: Addition of anaplasmosis, babesiosis, and Powassan virus as Designated Diseases of Public Health Significance

The purpose of this Advisory Alert is to make you aware of the approved amendments to Ontario Regulation 135/18 (Designation of Diseases) and Ontario Regulation 569 (Reports) under the Health Protection and Promotion Act (HPPA).

In response to reports of emerging tick-borne diseases and an increase in blacklegged tick populations across the province, Ontario has approved amendments to Ontario Regulation 135/18 to add anaplasmosis, babesiosis, and Powassan virus as Diseases of public health significance (DoPHS). In addition, the approval of amendments to Ontario Regulation 569 specifies new reporting requirements for these new DoPHS to Medical Officers of Health. The effective date for these amendments is July 1, 2023.

Public Health Ontario (PHO) will be developing disease-specific pages available from the Vector-Borne and Zoonotic Diseases webpage that will include Test Information Sheets that are specific for each tick-borne disease.

Diseases of public health significance must be reported to the Medical Officer of Health immediately or by the next working day. Reporting is required in accordance with Ontario Regulation 135/18 and amendments under the Health Protection and Promotion Act. Reports can be faxed or emailed to 705.677.9618 or

For information on enteric, vector-borne, zoonotic, or water-borne diseases, please call 705.522.9200, ext. 464 (toll-free 1.866.522.9200) to speak with a public health inspector. If you require an immediate response after hours or on public holiday closures, please call 705.688.4366.


Original Signed By

Dr. David Williams, Acting Medical Officer of Health


On behalf of Penny Sutcliffe, MC, MHSc, FRCPC

Medical Officer of Health and Chief Executive Officer

This item was last modified on June 30, 2023