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SUMMARYThe Brazilian Ministry of Health recommends the culling and euthanasia of dogs with a positive serological test for canine visceral leishmaniasis (CVL). In the Municipality of Rio de Janeiro, the technique used for the diagnosis of CVL is the indirect fluorescent antibody test (IFAT), using blood samples eluted on filter paper (eluate). A dog survey was conducted over a period of one year in the region of Carapiá, in order to evaluate the diagnosis of CVL in this region. All animals underwent clinical examination, and blood samples (serum and eluate) were collected for analysis by enzyme immunoassay (ELISA) and IFAT. A skin biopsy was obtained for parasitological examination (culture). A total of 305 animals were studied and Leishmania chagasi was isolated from nine animals. Sensitivity and specificity were 100% and 96.6% for ELISA, respectively, 100% and 65.5% for IFAT (cut-off at a 1:40 dilution), 100% and 83.4% for IFAT (cut-off at a 1:80 dilution), and 22.2% and 97.0% for eluate IFAT. In conclusion, ELISA was the best tool for the diagnosis of CVL among the serological techniques tested. The present results suggest the need for a better evaluation of filter paper IFAT as the only diagnostic method for CVL in the Municipality of Rio de Janeiro.

Resumo: Foi avaliada a associação entre características ambientais obtidas por sensoriamento remoto e a prevalência da leishmaniose visceral canina (LVC) no bairro do Jacaré, área de recente introdução da doença, no Município de Niterói, Estado do Rio de Janeiro, Brasil. Trata-se de um estudo seccional para avaliação da prevalência de LVC, definida por meio da positividade no teste imunocromatográfico rápido em dupla plataforma (dual path platform - DPP), confirmada com o ensaio imunoenzimático (EIE). Foram incluídos 97 cães com prevalência de LVC de 21,6%. Houve maior frequência de LVC em cães com a convivência com outro cão, gambá, mico e ouriço-terrestre, assim como com a história de remoção de outros cães com LVC do domicílio. Na análise multivariada, ajustada por sexo e idade do cão, cães residentes em áreas com maior cobertura de vegetação esparsa apresentaram prevalência da infecção por Leishmania infantum cinco vezes maior do que aqueles que residiam em áreas menos vegetadas (OR = 5,72; IC95%: 1,47-22,20). Por outro lado, áreas mais urbanizadas caracterizadas como comerciais ou residenciais carentes, identificadas pelo sensoriamento remoto como aquelas com alta densidade de estruturas cinza, estiveram associadas à menor ocorrência da LVC (OR = 0,09; IC95%: 0,01-0,92). A maior prevalência de infecção em cães convivendo com outros animais silvestres e em áreas com maior cobertura vegetal, associada com menor prevalência em áreas urbanizadas, indica um padrão rural de transmissão da LVC nessa área.

SUMMARYAmerican visceral leishmaniasis is a vector-borne zoonosis in expansion in Brazil. Dogs are the main urban reservoir. Departing from a case of canine visceral leishmaniasis (CVL) in Jacaré, Niterói, Rio de Janeiro State, an epidemiological canine and entomological study was performed to assess the extension of the disease at the location. Sample was collected around the case and the dogs identified by serological tests (rapid double platform immunochromatographic exams, immunoenzymatic assay/ELISA, indirect immunofluorescence/IFAT). The parasitological diagnosis was performed in animals positive in at least one of these tests. The entomological study was carried out by using light traps and manual collection. The associations between canine variables and outcome (ELISA and IFAT reagents) were assessed by the chi-square test and adjusted by multivariate logistic regression for those associations with p < 0.1 in the bivariate analysis. Seventeen cases of CVL were detected among 110 evaluated dogs (prevalence of 15.5%). Presence of ectoparasites (OR 6.5; 95% CI 1.1-37.4), animals with clinical signs (OR 9.5; 95% CI 1.2-76.6), and previous cases of CVL in the same house (OR 17.9; 95% CI 2.2-147.1) were associated with the outcome. Lutzomyia longipalpiswas not detected. Our results are indicative of an ongoing transmission in the area.

After the report of a second case of canine visceral leishmaniasis (CVL) in São Bento da Lagoa, Itaipuaçu, in the municipality of Maricá, Rio de Janeiro State, an epidemiological survey was carried out, through active search, totaling 145 dogs. Indirect immunofluorescence assay (IFA), enzyme-linked immunosorbent assay (ELISA), and rapid chromatographic immunoassay based on dual-path platform (DPP(r)) were used to perform the serological examinations. The parasitological diagnosis of cutaneous fragments was performed by parasitological culture, histopathology, and immunohistochemistry. In the serological assessment, 21 dogs were seropositive by IFA, 17 by ELISA, and 11 by DPP(r), with sensitivity of 66.7%, 66.7% and 50%, and specificity of 87.2%, 90.2% and 94%, respectively for each technique. The immunohistochemistry of bone marrow using the cell-block technique presented the best results, with six positive dogs found, three of which tested negative by the other parasitological techniques. Leishmania sp. was isolated by parasitological culture in three dogs. The detection of autochthonous Leishmania infantum in Itaipuaçu, and the high prevalence of seropositive dogs confirm the circulation of this parasite in the study area and alert for the risk of expansion in the State of Rio de Janeiro.

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