Echocardiographic and Hematological Changes in Dogs Naturally Infected with <i>Ehrlichia</i> Spp.

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&lt;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.