Evaluation of adenosine 5'-diphosphate (ADP)- and collagen-induced platelet aggregation in canine leishmaniasis.

Abstract Leishmania-infected dogs, which represent an important reservoir of infection in many parts of the world, frequently suffer from haematological disorders, including thrombocytopenia. In this study, the ability of platelets from healthy (control) dogs ( n =11) and from dogs with naturally acquired clinical leishmaniasis ( n =24) to aggregate in the presence of two different agonists (adenosine 5′-diphosphate [ADP] and collagen) was assayed. Haematological parameters examined consisted of the platelet count, prothrombin time, activated partial thromboplastin time (aPTT), fibrinogen concentration and D-dimer concentration. In dogs with leishmaniasis, a significant decrease in ADP- and collagen-induced platelet aggregation was observed. Compared with platelets from the control dogs, those from leishmania-infected dogs showed a higher sensitivity to collagen, as demonstrated by a reduction in platelet aggregation of up to 20.4%, and a significant ( P P