Leishmaniose visceral canina: avaliação de métodos para detecção de IgG em amostras de soro e eluato

The 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.O Ministério da Saúde recomenda a eutanásia de cães sororreatores como controle da leishmaniose visceral canina (LVC). No Município do Rio de Janeiro, a técnica utilizada para o diagnóstico da LVC é o teste de imunofluorescência indireta (IFI), utilizando amostras de sangue eluídas em papel de filtro (eluato). Um levantamento, durante um ano, foi conduzido na região de Carapiá, a fim de avaliar o diagnóstico da LVC nesta região. Todos os animais foram submetidos a exame clínico e coleta de sangue (soro e eluato) para realização do ensaio imunoenzimático (ELISA) e imunofluorescência indireta (IFI). Biópsia de pele foi obtida para o exame parasitológico (cultura). Foram avaliados 305 (89,4%) animais de uma população de 341 cães e Leishmania chagasi foi isolada de nove animais. A sensibilidade e especificidade do ELISA foram de 100% e 96,6%, na IFI (ponto de corte 1:40) de 100% e 65,5%, na IFI (ponto de corte 1:80) de 100% e 83,4% e na IFI (eluato) de 22,2% e 97,0%, respectivamente. A partir dos resultados obtidos podemos concluir que entre as técnicas sorológicas empregadas, o teste de ELISA apresentou-se como a melhor ferramenta para o diagnóstico da LVC. Os resultados sugerem a necessidade de uma melhor avaliação do teste de IFI realizada com eluato, como único método de diagnóstico para LVC no município do Rio de Janeiro

Canine visceral leishmaniasis: study of methods for the detection of IgG in serum and eluate samples

The 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