Forty dogs from the periphery of the city of Rio de Janeiro were studied. All dogs where diagnosed as positive for leishmaniasis either parasitologically and/or serologically. Among them, 19 came from areas where only Visceral Leishmaniasis (VL) occurs (Realengo, Bangu, Senador Camará). Clinical signs of the disease were seen in 36.8% of the cases, including emaciation - 100%, lymphadenopathy and depilation - 85.7%. The other 21 dogs came from an area (Campo Grande) where both diseases (VL, and American Cutaneous Leishmaniasis - ACL) occur. Clinical signs of the disease, mainly cutaneous or mucocutaneous ulcers were seen in 76.2% of the cases. Leishmania parasites were found in 39 cases: 22% in viscera, 42.5% in viscera and normal skin and 35% in cutaneous or mucocutaneous ulcers. All the Leishmania stocks isolated from dogs which came from Realengo, Bangu, Senador Camará (VL area), and from Campo Grande (VL + ACL area) were characterized as L. donovani (except in one case) according to their schizodeme, zymodeme and serodeme. The only stock characterized as L. b. braziliensis, was isolated from the lymph node of a dog from Campo Grande with visceral disease and without skin lesions. Antimony therapy attempted in eight Leishmania donovani positive dogs was unsuccessful.

Cutaneous biopsies (n = 94) obtained from 88 patients with American tegumentary leishmaniasis were studied by conventional and immunohistochemical techniques. Specimens were distributed as active lesions of cutaneous leishmaniasis (n = 53) (Group I), cicatricial lesions of cutaneous leishmaniasis (n = 35) (Group II) and suggestive scars of healed mucosal leishmaniasis patients (n = 6) (Group III). In addition, active cutaneous lesions of other etiology (n = 24) (Group C1) and cutaneous scars not related to leishmaniasis (n = 10) (Group C2) were also included in the protocol. Amastigotes in

Immunofluorescence tests (IF) for toxoplasmosis were performed on a total of 608 schoolchildren in elementary and junior high grades. 166 being in the Bonsucesso district (an urban region of Rio de Janeiro) and 442 children from locations within the lowlands of Jacarepaguá (with rural characteristics). All the IF-IgM were nonreactive, whilst 416 schoolchildren (68.4%) were IF-IgG serum-reactive (greater than or equal to 1:16). The percentages of serum-reactives in Jacarepaguá were significantly higher than in Bonsucesso, both as regards the total number of schoolchildren (p less than 0.001), as also when subdivided according to the age-grades from six to eight years (p less than 0.001) or from twelve to fourteen (p less than 0.05). Both in Jacarepaguá and in Bonsucesso, the prevalence of reactions in the 12 to 14 year age-grade was significantly greater than in the 6 to 8 year age-grade (p less than 0.001 in both cases). Expressively larger prevalences of serum reactions were found in Jacarepaguá among schoolchildren who preferred eating raw or undercooked meat, as well as among those having cats as pets; this occurred equally in the 6 to 8 year and in the 12 to 14 year age-grades. In Bonsucesso, the only significant difference was in the 6 to 8 year age-grades that had cats as pets. Thus, it has been verified that the risk of infection is greater and more precocious in localities with rural characteristics than in urban regions.

Due to the diversity of its physiological and pathophysiological functions and general ubiquity, the study of nitric oxide (NO) has become of great interest. In this work, it was demonstrated that Leishmania amazonensis promastigotes produces NO, a free radical synthesized from L: -arginine by nitric oxide synthase (NOS). A soluble NOS was purified from L. amazonensis promastigotes by affinity chromatography (2', 5'-ADP-agarose) and on SDS-PAGE the enzyme migrates as a single protein band of 116.2 (+/-6) kDa. Furthermore, the presence of a constitutive NOS was detected through indirect immunofluorescence using anti-cNOS and in NADPH consumption assays. The present work show that NO production, detected as nitrite in culture supernatant, is prominent in promastigotes preparations with high number of metacyclic forms, suggesting an association with the differentiation and the infectivity of the parasite.

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