Anaplasmosis, Canada’s second most common tick-borne infection, has triggered a severe case of acute focal myocarditis in a 79-year-old rural Ontario resident. The patient recovered fully after targeted doxycycline therapy.
Doxycycline Cures Tick-Borne Infection in Ontario Patient
- What happened: A patient in eastern Ontario developed a serious heart inflammation and confusion from a tick-borne bacterial infection, despite not remembering any tick bite.
- How it was treated: Physicians diagnosed the condition using blood smears and polymerase chain reaction (PCR) tests, curing the infection with the antibiotic doxycycline.
- Why it matters: As the range of the blacklegged tick expands across Canada, physicians must look for tick-borne diseases even when patients report no known bites.
Expanding Geographic Vectors and Diagnostic Challenges in Eastern Ontario
The patient, a 79-year-old man with a medical history including type 2 diabetes and ulcerative colitis, presented to a community hospital in July following two days of fatigue, chills, and weakness that resulted in a fall. At admission, he exhibited a high fever of 39.8°C, lymphopenia, thrombocytopenia, and acute kidney injury. Initial treatment with broad-spectrum ceftriaxone failed to halt his decline.
By the second day, the patient developed altered mental status, mild dyspnea, and worsening cytopenias. Blood smears subsequently revealed intracytoplasmic morulae within neutrophils, identifying Anaplasma phagocytophilum. Real-time polymerase chain reaction testing confirmed the diagnosis.
Transthoracic echocardiography showed a newly reduced ejection fraction of 43 percent with global left ventricular hypokinesia. Cardiac magnetic resonance imaging confirmed acute focal myocarditis, showing myocardial edema and late gadolinium enhancement in the basal inferolateral wall.
Clinical Comparison of Tick-Borne Pathogens in Canadian Healthcare
Anaplasmosis is transmitted by the blacklegged tick, Ixodes scapularis, whose geographic range continues to grow across Canada. First described in the northeastern United States in 1994, the infection is now a reportable disease, with provincial surveillance data from Ontario showing rising infection rates among tick vectors. While most cases present with mild, flu-like symptoms including fever, malaise, headache, and gastrointestinal distress, severe organ-specific complications can occur.
| Tick-Borne Infection | Primary Vector | Common Laboratory Findings | Primary Organ Complications |
|---|---|---|---|
| Anaplasmosis | Ixodes scapularis | Thrombocytopenia, lymphopenia, elevated ALT and creatinine | Myocarditis, acute respiratory distress syndrome, acute kidney injury |
| Lyme Disease | Ixodes scapularis | Variable | Atrioventricular block, facial palsy, meningitis |
| Babesiosis | Ixodes scapularis | Hemolytic anemia, thrombocytopenia | Renal failure, severe hemolysis |
Complications affecting target organs remain uncommon, occurring in fewer than 10 percent of recorded cases. Advanced age, immunosuppression, and chronic comorbidities such as diabetes elevate the risk of severe disease. Unlike Lyme disease, anaplasmosis targets blood cells and can induce multi-organ strain without any visible skin rash or remembered bite.
Doctors Should Treat Suspected Tick-Borne Infections Immediately
Doxycycline serves as the empirical and definitive treatment for anaplasmosis and should be administered immediately when tick-borne infections are suspected in endemic regions. Healthcare providers must evaluate patients presenting with unexplained fever, thrombocytopenia, and elevated liver enzymes in regions where Ixodes scapularis is established. Patients experiencing persistent fever, confusion, chest discomfort, or shortness of breath following outdoor exposure in wooded areas of Ontario, Quebec, or Manitoba must seek immediate medical evaluation.
References
- CMAJ: Anaplasmose et myocardite attribuables à une piqûre de tique dans l’est de l’Ontario
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