Interpretation of Coagulation Tendency Contributing to Thrombosis in Vector-Borne Diseases (Ehrlichiosis, Anaplasmosis, Leishmaniosis, and Dirofilariasis) among Dogs

Abstract

Background: Vector-borne infectious and zoonotic diseases are an important health problem that directly affects human and animal health negatively. Results through evaluation of coagulation disorders among vector-borne diseases should be of beneficial for both human and dogs studies. According to the present author’s knowledge reports regarding changes in platelet (PLT) count, prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB) and D-dimer levels in dogs naturally infected with one or more vector-borne pathogens are lacking. Therefore, the present study was aimed to detecting those parameters for relation between diagnosis and prognosis of vector-borne diseases among dogs.

Materials, Methods & Results: The material of this study was 46 dogs (36 were naturally infected with vector-borne diseases and 10 were healthy) from different breed, age and of both sexes. Venous blood samples were obtained to detect PLT counts, antibodies of ehrlichiosis, anaplasmosis, borreliosis, leishmaniosis and antigens of Dirofilaria immitis. The diagnosis of vector-borne diseases was performed by using a commercial ELISA assay kits. PLT count was performed with an automated blood cell counter analyser. In addition, PT, APTT and FIB concentrations were measured using a microcoagulometer. D-dimer concentrations were determined using fluorescence immunoassay rapid quantitave test analyser. Subgroups were formed according to the number of cases and the distribution of vector-borne agent. Statistically significant decreased PLT count was found in dogs mono infected with ehrlichiosis compared to healthy dogs (P < 0.001). Changes in mean PT value in the studied animals did not show statistically significant differences among the groups
 (P > 0.05). APTT values in the ehrlichiosis mono infection group were significantly higher than that of the healthy control
 (P < 0.01). A significant increase in FIB levels were detected for ehrlichiosis mono infection and ehrlichiosis - leishmaniosis co infection versus healthy control (P < 0.001). Plasma D-dimer concentrations were found to be higher in all groups infected with vector borne diseases compared to healthy group (P < 0.001) and the differences between infected groups were not statistically significant.

Discussion: Bleeding disorders such as epistaxis, haematuria and haemorrhagic diarrhoea has been reported in dogs with vector-borne diseases. These disorders represent the main cause of death in dogs. In the present study, thrombocytopenia was observed in dogs mono infected with ehrlichiosis compared to healthy. This finding is in agreement with those reported in dogs with ehrlichiosis. Plasma FIB is one of the most important factors in the coagulation cascade. In the present study, a significant difference between dogs with ehrlichiosis mono infection and ehrlichiosis - leishmaniosis co infection versus healthy controls group was observed. PT and APTT are commonly used in evaluating dogs with bleeding tendencies. In the present study, a significant difference between dogs with ehrlichiosis and with healthy control was observed in APTT values, however, differences in PT values compared to healthy dogs were insignificant. No statistical difference in PT values might be related to the lower sensitivity of the commercial PT assays. In dogs, D-dimer concentrations can be elevated due to disseminated intravascular coagulopathy, infections, metabolic disorders, neoplasia and post-surgically. In the present study, a significant increase in D-dimer concentration was observed in all dogs with vector-borne diseases. This finding points to the activation of the fibrinolysis system in consequence of thrombophilia. In conclusion, elevations presented in coagulation biomarkers such as APTT, FIB and D-dimer in the present study were interpreted as with the effects of vector-borne diseases. It may be briefly suggested that D-dimer levels as a marker of pro-coagulatory activity, as well as fibrinolysis, indicates the highly active and excessive coagulation, and all through are risk factors for thromboembolic disorders. Therefore, these findings should be considered in the diagnosis, treatment and prognosis of the vector-borne diseases in dogs.