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An autochthonous case of visceral leishmaniasis is reported in a dog (Canis familiaris) as an apparently natural infection in a non-endemic area. DNA obtained from spleen and liver samples produced the expected fragment in a Leishmania-specific rDNA-based nested-PCR assay. The PCR product, a 490 bp fragment, was sequenced and the nucleotide sequence was identical to that of Leishmania (Leishmania) infantum chagasi. These results are surprising since no autochthonous human or canine cases of visceral leishmaniasis have ever been reported in this municipality. This case suggests that natural transmission of this disease is occurring in this area.

A serological survey was made in 973 stray dogs caught near green areas in S. Paulo county by the indirect immunofluorescence test. No positive serum was found, however autochthonous human cases of ACL that occurred in the county show the circulation of the parasite in the environment. This fact, associated with the existence of the vectors and the apparent absence of infected dogs in the areas studied, suggest that stray dog plays an insignificant role in the spread of the parasite. The cycle of the parasite in Sao Paulo county has been maintained by wild animals, hence the dog would be an accidental host just as humans.

A natural case of co-infection by Leishmania and Trypanosoma is reported in a dog (Canis familiaris) in south- western state of Mato Grosso do Sul, Brazil. Both amastigote and trypomastigote forms were observed after Giemsa staining of cytological preparations of the dog's bone marrow aspirate. No parasite was detected using medium culture inoculation of the sample. DNA obtained from the bone marrow aspirate sample and from the blood buffy coat was submitted to polymerase chain reaction (PCR) with a set of rDNA-based primers S4/S12. The nucleotide sequence of the PCR product was identical to that of Trypanosoma (Trypanozoon) evansi. The S4/S12 PCR was then used as template in a nested-PCR using a specific Leishmania set S17/S18 as primers, to explain the amastigote forms. The nucleotide sequence of the new PCR product was identical to that of Leishmania (Leishmania) chagasi. This case, as far as we know, is the first report of a dog co-infected with these parasites, suggesting that besides L. (L.) chagasi, the natural transmission of T. (T.) evansi occurs in the area under study.

A serological survey among domestic and stray dogs of the municipality of S o Jos do Rio Preto, Brazil, was conducted to identify infected animals and detect the chances of transmitting the American visceral leishmaniasis. From November 1998 to June 2000, 2,104 sera samples were tested by indirect immunofluorescence reaction, using as antigen promastigotes of Leishmania (L.) chagasi. There were 2,092 no reactive samples and 12 reactive ones. Of the dogs with reactive serum it was possible to prepare lesion smears in only 3. The slide was stained by Giemsa method and only in one of them it was found amastigotes forms characteristic of Leishmania sp. This finding suggests the need of canine serological and entomological surveillance in S o Jos do Rio Preto for an early detection of any local epidemiological changes.

Realizou-se inquérito sorológico em cães domiciliados e errantes do Município de São José do Rio Preto, SP, para identificar animais infectados e detectar a possibilidade de transmissão da leishmaniose visceral americana. De novembro de 1998 a junho de 2000, 2.104 amostras de soros foram testadas por meio da reação de imunofluorescência indireta, empregando-se como antígeno formas promastigotas de Leishmania (L.) chagasi. Observaram-se 2.092 amostras não reagentes e 12 reagentes. Dos cães com sorologia positiva foi possível realizar raspados de lesão em três animais. O material fixado em lâminas foi corado por Giemsa e, em apenas um, foram encontradas formas amastigotas características de Leishmania sp. Este resultado indica a necessidade de manutenção da vigilância sorológica canina e entomológica no município de São José do Rio Preto, a fim de detectar, precocemente, qualquer alteração na epidemiologia local. A serological survey among domestic and stray dogs of the municipality of São José do Rio Preto, Brazil, was conducted to identify infected animals and detect the chances of transmitting the American visceral leishmaniasis . From November 1998 to June 2000, 2,104 sera samples were tested by indirect immunofluorescence reaction, using as antigen promastigotes of Leishmania (L.) chagasi. There were 2,092 no reactive samples and 12 reactive ones. Of the dogs with reactive serum it was possible to prepare lesion smears in only 3. The slide was stained by Giemsa method and only in one of them it was found amastigotes forms characteristic of Leishmania sp. This finding suggests the need of canine serological and entomological surveillance in São José do Rio Preto for an early detection of any local epidemiological changes.