Abstract This study aimed to assess the severity of anemia, associated parameters, and their impact on cardiac function in dogs naturally infected with Ehrlichia canis ( E. canis ), a zoonotic pathogen primarily transmitted by the brown dog tick. Forty-seven dogs, comprising 38 infected and 9 healthy controls, were classified into non-anemic (n=12), mildly mild (n=9), moderately (n=11), severely (n=4), and very severely anemic (n=2), groups. Hematological and echocardiographic assessments were performed, along with separate measurements of cardiac biomarkers (e.g., cardiac troponin I cTnI) and iron metabolism biomarkers (e.g., serum iron, total iron-binding capacity TIBC, and transferrin saturation). Hematological analysis revealed a significant reduction in hematocrit (17.11±1.34%), hemoglobin (5.22±0.88 g/dL), and platelet counts (38.25±22.62×10⁹/L) in severely anemic dogs compared to other groups. Echocardiographic findings demonstrated increased interventricular septal thickness during diastole (1.16±0.60 cm) and systole (1.38±0.10 cm) in moderately anemic dogs, indicating compensatory adaptations. Dogs with severe anemia exhibited elevated left ventricular end-diastolic (3.56±0.54 cm) and end-systolic dimensions (1.71±0.22 cm) in comparison to control dogs (p<0.05). Fractional shortening (53.83±7.71%) and ejection fraction (77.58±8.19%) were diminished among the severely anemic group, denoting altered cardiac function. Elevated cardiac troponin I (cTnI) levels (up to 0.29±0.22 ng/mL) were noted in a limited number of cases, suggesting that myocardial injury was not widespread. This study demonstrated that anemia severity significantly influences myocardial and hematological parameters in E. canis -infected dogs, with evidence indicating compensatory cardiac remodeling in response to chronic anemia. Further research utilizing advanced diagnostic techniques is recommended to better understand disease progression and associated complications.
Ustaer et al. (Mon,) studied this question.