Canine visceral leishmaniasis with amyloidosis: an immunopathological case study

Canine leishmaniasis caused by Leishmania leishmania infantum in two Labrador retrievers

Canine leishmaniasis, a generally fatal parasitic disease, was diagnosed in 2 dogs with a medical history of foreign travel, lymphadenopathy, emaciation, anorexia, intermittent fever, and cutaneous lesions. Clinically, hyperproteinemia, proteinuria, azotemia, and glomerulopathy were evident. Isolation of Leishmania species was done using Schneider's Drosophila medium. Syrian hamsters were used for infectivity studies. Clear taxonomic identification was done biochemically by isoenzyme analysis and comparison of zymogram banding patterns with 6 World Health Organization reference strains. Based on the geographic origin of affected dogs, clinicopathologic presentation, visceralization with hepatosplenomegaly in hamsters, and isoenzyme analysis, a diagnosis of Leishmania leishmania infantum was made. This study, representing the first taxonomic identification of an isolate from canine leishmaniasis, demonstrates the zoonotic and epidemiologic implications of this disease.

Erosive colitis in experimental canine Leishmaniasis

Six 4 month-old beagles were inoculated with Leishmania infantum, three of them intraperitoneally (Group A) and the other three intravenously (Group B). The animals from Group A were killed at 109, 433 and 592 days after inoculation and animals from Group B 109, 171 and 334 days after inoculation. At 350 days (Group A) and 275 days (Group B) after inoculation, dogs started to develop a chronic large bowel diarrhoea. At necropsy a diffuse colonic and rectal wall thickening of gradually increasing severity was observed. Histological examination of the colon showed a diffuse inflammatory infiltration of the mucosa and submucosa by macrophages with amastigotes, lymphocytes, plasma cells and some neutrophils and eosinophils. The surface epithelium developed increasingly extensive degeneration, which caused the development of erosions on the mucosal surface. The crypts of Lieberkühn decreased in number and showed degeneration of the crypt epithelium.

[Optical and electron microscopic study of the kidney of dogs naturally and experimentally infected with Leishmania (Leishmania) chagasi]

Two naturally infected dogs (male and female) from Teófilo Otoni (MG-Brazil) were maintained for 18 months in our laboratory. Two other dogs, two months old males were infected with 1 x 10(6) promastigotes of MHO/BR/70/BH46 Leishmania (Leishmania) chagasi strain, endovenous route, and autopsied after 10 months and two years. The main findings concerning the kidney were: (1) focal or diffuse mesangial glomerulonephritis with proliferative and enlargement of mesangial cells; (2) increase in thickness of basement membrane with electron-dense deposits; (3) chronic interstitial nephritis with intense exudation of plasmocytes; (4) cloud swelling of renal tubules. The authors discuss the probable pathogenetic mechanisms.

Interstitial pneumonitis in canine visceral leishmaniasis

Forty-one naturally infected dogs with visceral leishmaniasis from an urban area of Corumbá (Mato Grosso do Sul-BRAZIL) were studied and three types of lung involvement due to visceral leishmaniasis were characterized; a cellular, a cellular-fibrotic and a fibrotic type. These types seem to represent a sequential evolutive proce'as. Visceral leishmaniasis frequently causes an interstitial pneu monitis in naturally infected dogs (80.5%) as well as in man and experimentally infected hamsters.

Visceral leishmaniasis in the German shepherd dog. I. Infection, clinical disease, and clinical pathology

Two groups of three German shepherd dogs each were inoculated with Leishmania chagasi or Leishmania donovani amastigotes and the infection was followed for 82 days. The dogs developed a persistent infection, became thin, and developed splenomegaly and lymphadenomegaly by 55 days after inoculation. All dogs developed a normocytic, normochromic anemia of increasing severity. Thrombocytopenia and leukopenia occasionally occurred. Blood tryptophan levels were decreased significantly in infected dogs. Increased total serum protein, with hypergammaglobulinemia and hypoalbuminemia, was present in all dogs to various degrees. There was a marked increase in gamma globulins, with smaller increases in alpha and beta globulins. Many of the clinicopathologic changes observed in these dogs were similar to the disease as it occurs in man. The German shepherd dog may be a useful laboratory model for the study of visceral leishmaniasis.