Haemostatic Disorders in Dogs Naturally Infected by Leishmania infantum

Hemostatic assessment of dogs associated with hepatic parasite load of Leishmania infantum chagasi

Leishmania infantum chagasi liver parasite load was compared to hemostatic abnormalities, as well as to clinical, laboratorial, and histopathological findings in dogs with visceral leishmaniasis. The liver parasite load of 30 dogs L. infantum chagasi naturally-infected was evaluated by quantitative real- time PCR and the results were compared with serum biochemistry and primary and secondary hemostasis findings. Moreover, hepatic histological lesions were described in these dogs. Prolonged bleeding time, prothrombin time (PT), and activated partial thromboplastin time (APTT), were observed in the group with visceral leishmaniasis. Eleven dogs presented inflammatory liver lesions, with predominance of mild multifocal mononuclear periportal hepatitis. No association between the presence of parasites and abnormalities in screening tests was observed by Spearman's rank correlation coefficient. The clinical progression in leishmaniasis is associated with the occurrence of hemorrhagic diathesis, which depends not only on the presence of the parasite but also the inflammatory process, compromised immunological response, hepatic and renal failure in symptomatic dogs.

An update on the diagnosis and treatment of canine leishmaniosis caused by Leishmania infantum (syn. L. chagasi)

Canine leishmaniosis caused by Leishmania infantum is still a common disease in endemic areas, such as the Mediterranean countries, and has progressively expanded into non-endemic areas like Central and Northern Europe. The aim of this article is to critically review current knowledge on the diagnosis and treatment of this disease. In dogs with typical clinical signs and clinicopathological abnormalities, diagnosis is relatively easy based on the exclusion of major differentials, the demonstration of the parasite (e.g., with lymph node and/or skin cytology) and the presence of Leishmania-specific immunoglobulin G antibodies (quantitative serology). In less typical cases, these criteria together with the exclusion of possible differentials and the demonstration of compatible histological lesions in affected organs and tissues form the basis for a sound diagnosis. In clinically healthy dogs, molecular techniques are the most sensitive means for detecting L. infantum infection. Treatment of canine leishmaniosis should follow clinical staging and is usually based on meglumine antimonate or miltefosine administration for a few weeks in combination with allopurinol for several months. However, allopurinol monotherapy may be used in very mild cases as well as in dogs with end stage kidney disease. Aminosidine administered once daily at a revised dosage shows some promise but additional controlled studies are needed. Close attention to published guidelines regarding treatment and follow-up is necessary to achieve the best possible therapeutic outcome.

Relationship between Leishmania IFAT titer and clinicopathological manifestations (clinical score) in dogs

During canine leishmaniasis (CanL) due to Leishmania infantum, high levels of antibodies production are associated with the presence of various clinical signs, because of the deposition of soluble immune complexes in organs and tissues. The immunofluorescence antibody test (IFAT) is one of the most commonly used techniques for detection of anti-Leishmania antibodies. The purpose of this study was to assess whether there is a correlation between clinical signs and IFAT titers in dogs naturally infected with Leishmania. A retrospective study was performed on medical records of 49 dogs diagnosed with CanL. Information extracted from the medical records of each dog with CanL was clinical score, IFAT titer, serum total protein (TP), gamma globulin (IgG) and creatinine concentration, and protein creatinine ratio in urine sample (UP/UC) at each follow-up examination. Results show that dogs with highest IFAT titers recorded had higher mean clinical scores indicating a positive relationship (P < 0.0001) between anti-Leishmania antibodies (IgG) and clinical manifestations, which becomes more evident in severe clinical forms of canine leishmaniasis. Higher TP and IgG serum concentrations were recorded in dogs with higher clinical scores. Significant association was observed between UP/UC and the IFAT titer (P = 0.004).