Hemostatic abnormalities in uncomplicated babesiosis (Babesia rossi) in dogs

Background: Babesiosis in dogs is associated with severe thrombocytopenia; yet infected dogs rarely show clinical signs of hemorrhage.

Hypothesis: Dogs with uncomplicated babesiosis have normal hemostatic capacity despite severe thrombocytopenia.

Animals: Nineteen client-owned dogs with uncomplicated babesiosis; 10 healthy controls.

Methods: A prospective, cross-sectional, observational study. Thromboelastography (TEG), prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, D-dimers, and antithrombin (AT) measured in both groups. Statistical significance set at P < .01.

Results: Babesiosis group hematocrit and platelet count significantly lower than controls (0.29 versus 0.50 L/L; P < .001 and 20.0 versus 374.5 × 10(9)/L; P < .001, respectively). Except for K, no significant difference in TEG variables between groups. Hemostatic variables for babesiosis group versus controls (mean ± SD); R: 5.9 ± 1.8 versus 4.6 ± 0.9 min (P = .048); K: 2.8 ± 1.1 versus 1.9 ± 0.6 min (P = .003); angle: 55.5 ± 11.7 versus 62.2 ± 4.1 degrees (P = .036); MA: 48.4 ± 9.7 versus 57.2 ± 5.2 mm (P = 0.013); G: 5.1 ± 1.9 versus 6.9 ± 1.5 dyn/cm(2) (P = .019); LY30 (median, range): 0 (0-5.7) versus 0.6% (0-6.1) (P = .152); and LY60: 0 (0-8.8) versus 3.1% (0-13.1) (P = .012). AT activity significantly lower (105.2 ± 16.5 versus 127.8 ± 15.4%; P = .001). Fibrinogen concentration significantly higher in babesiosis group (5.7 ± 1.3 versus. 3.0 ± 0.7 g/L; P < .001).

Conclusion and clinical importance: Despite severe thrombocytopenia, dogs with uncomplicated babesiosis did not have clinical signs of hemorrhage and TEG variables were normal, which could indicate a normocoagulable state.