Thrombosis and nephritic syndrome in a dog with visceral leishmaniasis

Disseminated intravascular coagulation in a dog naturally infected by Leishmania (Leishmania) chagasi from Rio de Janeiro - Brazil

BACKGROUND

Disseminated intravascular coagulation (DIC) is an acquired disorder characterized by the activation of intravascular coagulation and excessive fibrin formation. It always occurs in association with other clinical conditions, including parasitic diseases. DIC has been described as a unusual complication in human and canine visceral leishmaniasis.

CASE PRESENTATION

DIC was found in a seven-year-old male mongrel dog naturally infected by Leishmania (Leishmania) chagasi. Haemostasis parameters demonstrated changes in primary and secondary haemostasis and fibrinolysis.

CONCLUSION

DIC is a unusual condition described in canine visceral leishmaniasis and it seems to be associated with several immunological and pathological mechanisms involved in the disease.

An immunohistochemical study in cases with usual and unusual clinicopathological findings of canine visceral leishmaniosis

The present study describes pathologic findings and immunohistochemical diagnosis of canine visceral leishmaniasis (CVL) in 22 dogs who died naturally in the Aegean region of Turkey. At necropsy, lymphadenomegaly, hepatosplenomegaly, hepatic, and nephrosclerotic lesions were conspicuous. Histopathologically, chronic inflammatory reactions of the spleen, lymph nodes, bone marrow, liver, and skin were marked findings. Cytological and histological examinations showed macrophages loaded with Leishmania amastigotes in these organs. Immunohistochemistry revealed that immunolabeling of amastigotes and/or parasite antigen, especially in the lymph nodes, spleen, bone marrow, liver, and skin, and occasionally, in the kidneys, intestines and lungs. Our laboratory results showed that immunohistochemistry should be included, along with cytological and histological examinations, in the diagnosis of CVL.

Forty years of visceral leishmaniasis in the State of Piaui: a review

Visceral leishmaniasis (VL) has been known to occur in the state of Piauí since 1934. The typically rural disease began to appear in urban areas over time, being concentrated mainly in Teresina, the capital of Piauí. Teresina was also affected by the first urban epidemic of VL in Brazil. Over 1,000 cases of the disease were reported during urbanization (1981-1986). Human population growth and migration led to land occupation on the outskirts of Teresina. These factors have contributed to vector proliferation, increasing the incidence of VL. At present, the incidence of human and canine disease is quite high and uncontrolled in Piauí. It seems that some measures, such as the elimination of seropositive dogs, failed to significantly reduce the number of new VL cases in Teresina. Despite previously conducted studies, little is known about VL epidemiology in urban areas. The aim of this review is to reveal the situation of VL in Teresina during the last 40 years, focusing on the major factors that may contribute to the high incidence and persistence of VL infection.

The effects of prednisone on haemostasis in leishmaniotic dogs treated with meglumine antimoniate and allopurinol

Thirty dogs naturally infected with Leishmania infantum were studied in order to determine the effects of treatment on haemostatic function. The animals were divided randomly into two treatment groups: Group 1 received meglumine antimoniate and allopurinol; Group 2 dogs were given the same treatment plus prednisone. Ten healthy animals were used as untreated controls. Clinical examination and determination of platelet aggregation, coagulation factors and biochemical parameters were undertaken before treatment and after 15, 30 and 60 days. A significant improvement in platelet aggregation was detected after 60 days in Group 1, but only after 15 days in Group 2. In both treated groups, platelet aggregation was lower than in the control group at the end of the study. The results suggest that prednisone may be a useful tool in the treatment of haemostatic disorders during canine leishmaniosis. The potential benefits and risks due to the use of corticosteroids in the treatment of leishmaniosis are discussed.

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

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 < 0.0001) difference for all the doses tested. With ADP the reduction was up to 10.4%, the difference reaching a significant level of P < 0.0001 only at the maximum dose used. The nature of this response, which was not accompanied by any clinical signs of bleeding other than an increase in aPTT, emphasizes the role of platelets in the parasite-host cell interaction.

Acute paraplegia associated with vasculitis in a dog with leishmaniasis

A 14-month-old female crossbreed dog with leishmaniasis, receiving allopurinol, was presented with acute paraplegia. A diagnosis of renal failure with pelvic limb lower motor neuron signs was made and the dog was euthanased. Histopathological examination demonstrated leukocytoclastic vasculitis in multiple organs. Malacia and haemorrhage affecting the spinal cord was associated with multiple foci of vasculitis within the nervous tissue. Rupture and thrombosis of inflamed vessels caused haemorrhage in the spinal cord and subsequent paralysis.

Atypical forms of canine leishmaniosis

Canine leishmaniosis is a common disease in the Mediterranean area, but sporadic cases in dogs having travelled through endemic regions are also reported. The disease's evolution is usually chronic and symptoms are either non-specific (fever, weight loss, lethargy, enlarged lymph nodes), dermatological, renal or ocular. The purpose of this article is to review the literature and to describe our own experience of certain atypical forms of canine leishmaniosis. These include specific skin lesions, monoclonal gammopathy, renal failure (without any other signs), chronic colitis, haemostatic problems and disorders of the cardiovascular, respiratory and musculo-skeletal systems.

Evaluation of the potential causes of epistaxis in dogs with natural visceral leishmaniasis

Haemostasis was evaluated in 19 dogs with natural Leishmania infection, six of them with a history of epistaxis, and the results were compared with the results from 24 healthy dogs. In addition, the dogs' blood pressure was measured and biopsies were taken from the nasal mucosa. Buccal mucosa bleeding time was prolonged in the dogs with leishmaniasis (P < 0.002) and most significantly in those with epistaxis (P < 0.005). None of the Leishmania-infected dogs had thrombocytopenia, low levels of plasma von Willebrand factor antigen, a prolonged prothrombin time or activated partial thromboplastin time, a low plasma fibrinogen concentration or high serum fibrin degradation products. These results rule out defects of secondary haemostasis or disseminated intravascular coagulation as significant causes of epistaxis in non-complicated leishmaniasis. Histopathology of the nasal mucosa of 10 of the affected dogs, three of them with epistaxis, revealed ulcerative and inflammatory lesions in all of them.

Evaluation of secondary haemostasis in canine leishmaniasis

Secondary haemostasis was evaluated in 26 dogs with leishmaniasis and 10 normal dogs by measurements of modified one-stage prothrombin time (m-OSPT), activated partial thromboplastin time (APTT), thrombin time, fibrinogen concentration and fibrin degradation products. There were no significant differences between the groups in the m-OSPT, fibrinogen concentration, or levels of fibrin degradation products. The APTT was significantly (P = 0.006) longer in the infected dogs than in the control group, and in infected dogs with alanine aminotransferase (ALT) activities > 50 U/litre. There was a significant linear regression between ALT and APTT. Thrombin time was significantly (P = 0.003) longer in the infected dogs than in the normal dogs. There were no significant differences between the thrombin times of sick dogs with different levels of creatinine or activities of ALT, or between male and female dogs, whether diseased or normal.

Evaluation of primary haemostasis in canine leishmaniasis

Primary haemostasis was evaluated by measurements of bleeding time and platelet count in 26 dogs with leishmaniasis and 10 normal dogs. Bleeding time was significantly (P = 0.02) longer in the infected dogs than in the control group, and in infected dogs with creatinine concentrations > 1.5 mg/dl than in infected dogs with normal creatinine levels. There was a significant linear regression between the concentration of creatinine and bleeding time (P = 0.02) although the coefficient of determination was low (r2 = 0.194). There were no significant differences in platelet counts between the normal and diseased dogs, and there were no significant differences between male and female dogs in either group.

Ultrasonographic localization of a caudal vena cava thrombus in a dog with leishmaniasis

A dog with visceral leishmaniasis developed rear limb edema, and distension of the caudal epigastric veins. Glomerular disease with nephrotic syndrome and hypercoagulable state was diagnosed. Sonographically there was massive thrombosis of the caudal vena cava.