Abstract
OBJECTIVE: To provide an overview of the diagnosis and management of patients with anaplasmosis, also known as human granulocytic anaplasmosis, a lesser-known tick-borne illness increasing in prevalence in Canada. SOURCES OF INFORMATION: A PubMed search was conducted between October 2024 and March 2025 using the search terms anaplasmosis and tick-borne illness with a focus on epidemiology, diagnosis, and management. Levels of evidence for treatment recommendations ranged from II to III, with most available data coming from case reports, case series, retrospective studies, and systematic reviews. MAIN MESSAGE: Tick-borne illnesses are becoming more prevalent in Canada due to the effects of climate change. Anaplasmosis is a lesser-known tickborne illness transmitted by the same vectors as Lyme disease. Patients with anaplasmosis commonly present with a nonspecific febrile illness, often without a distinctive rash. Leukopenia, thrombocytopenia, and mild transaminitis are commonly seen in bloodwork results. Family physicians in Canada should familiarize themselves with this relatively new entity and include it in their differential diagnosis when evaluating patients with fever of unknown origin. In such cases, polymerase chain reaction testing for anaplasmosis, alongside Lyme disease serology, should be considered. Patients with either disease respond well to treatment with doxycycline. CONCLUSION: With the expanding range of tick populations in Canada, the risk of anaplasmosis, along with other tick-borne illnesses, is becoming more prevalent. Increased awareness among family physicians is critical for timely diagnosis. Prompt recognition and treatment can reduce the risk of complications.