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

Comparative assessment of skin reactivity to thimerosal- or phenol-preserved Imunoleish® antigen in dogs with suspected American Tegumentary Leishmaniasis in an endemic area of the state of Rio de Janeiro, Brazil

The leishmanin skin test (LST), which is an in vivo test that assesses the cellular immune responses to Leishmania-derived antigens, is an important tool in the laboratory diagnosis of American tegumentary leishmaniasis (ATL). This study aimed to compare the results obtained in LST employing the Imunoleish® antigen preserved with thimerosal (AgT) or phenol (AgP) and serological techniques to detect a possible infection caused by Leishmania (Viannia) braziliensis in dogs. The study included 172 dogs from an area endemic for ATL in the municipality of Paracambi, state of Rio de Janeiro, Brazil. The results obtained with Imunoleish® antigen preserved with thimerosal (AgT) or phenol (AgP) and serological tests were compared. Each dog received, intradermally, 0.1 mL of each antigen on the inner side of the right (AgT) and left (AgP) thighs. Five (2.7%) dogs presented ATL lesions. Of these, two were reactive to both formulations and three were reactive only to AgT. Among the 172 dogs, 68 (39.5%) were reactive only to AgT, 16 (9.3%)  only to AgP, and 11 (6.4%) to both formulations. Twenty-one (12.2%) sera samples were reactive by immunofluorescent antibody test (IFAT) and 21 enzyme-linked immunosorbent assay (ELISA). However, in only two dogs out of the five which Leishmania was isolated from, serological tests were positive. The LST and serological tests could be a useful tool in the diagnosis of L. (V.) braziliensis infection in dogs. Standardization of the techniques and reagents used could allow comparative studies on sensitivity, specificity, and positive and negative predictive values in dogs from different regions.Keywords: American Tegumentary Leishmaniasis, Leishmanin skin test, Diagnosis, Dogs, Host

A utilização do ELISA empregando antígenos homólogos e heterólogos para a detecção de IgG e subclasses (IgG1 e IgG2) no diagnóstico de Leishmaniose visceral canina

Indirect immunofluorescence is the method recommended for the diagnosis of visceral leishmanisis in dogs, however, the accuracy of this technique is low and its use on a large scale is limited. Since ELISA does not present these limitations, this technique might be an option for the detection of IgG or specific IgG1 and IgG2 subclasses. Canine ehrlichiosis is an important differential diagnosis of American Visceral Leishmaniasis (AVL). The present study compared ELISA using Leishmania chagasi and Leishmania braziliensis antigen for the detection of anti-Leishmania IgG and subclasses in serum samples from 37 dogs naturally infected with L. chagasi (AVL) and in samples from four dogs co-infected with L. braziliensis and L. chagasi (CI). The occurrence of cross-reactivity was investigated in control serum samples of 17 healthy dogs (HC) and 35 infected with Ehrlichia canis (EC). The mean optical density obtained for the detection of IgG was significantly higher when L. chagasi antigen was used, and was also higher in subgroup VLs (symptomatic) compared to subgroup Vla (asymptomatic). The correlation between IgG and IgG1 was low. The present results suggest that IgG ELISA using homologous antigen yields the best results, permitting the diagnosis of asymptomatic L. chagasi infection and the discrimination between cases of AVL and ehrlichiosis in dogs.A imunofluorescência indireta é o método recomendado para o diagnóstico de leishmaniose visceral em cães, entretanto, a acurácia dessa técnica é baixa e seu uso em grande escala é limitado. Uma vez que o ELISA não apresenta essas limitações, essa técnica poderia ser uma opção para a detecção de IgG ou subclasses IgG1 e IgG2 específicas. A ehrlichiose canina é um importante diagnóstico diferencial de Leishmaniose Visceral Americana (LVA). O presente estudo comparou o ELISA usando antígenos de Leishmania chagasi e Leishmania braziliensis para a detecção de IgG e subclasses anti-Leishmania em amostras de soro de 37 cães naturalmente infectados com L. chagasi (LVA) e em amostras de quatro cães co-infectados (CI). A ocorrência de reatividade cruzada foi investigada em amostras de soro controle de 17 animais saudáveis (HC) e 35 de infectados por Ehrlichia canis (EC). A média de densidade óptica obtida para a detecção de IgG foi significantemente maior quando o antígeno de L. chagasi foi usado e também mais elevada no subgrupo LVs (sintomático) quando comparado ao subgrupo LVa (assintomático). A correlação entre IgG e IgG1 foi baixa. O presente resultado sugere que ELISA IgG empregando antígeno homólogo, produz os melhores resultados, permitindo o diagnóstico de infecção assintomática por L. chagasi e a discriminação entre casos de LVA e ehrlichiose em cães

Sporotrichoid leishmaniasis: a cross-sectional clinical, epidemiological and laboratory study in Rio de Janeiro State, Brazil

Background Atypical presentations of cutaneous leishmaniasis include sporotrichoid leishmaniasis (SL), which is clinically described as a primary ulcer combined with lymphangitis and nodules and/or ulcerated lesions along its pathway. Aims To assess the differences between patients with sporotrichoid leishmaniasis and typical cutaneous leishmaniasis (CL). Methods From January 2004 to December 2010, 23 cases of SL (4.7%) were detected among 494 CL patients diagnosed at a reference center for the disease in Rio de Janeiro State, Brazil. These 23 cases were compared with the remaining 471 patients presenting CL. Results SL predominated in female patients (60.9%, p = 0.024), with older age (p = 0.032) and with lesions in upper limbs (52.2%, p = 0.028). CL affected more men (64.5%), at younger age, and with a higher number of lesions exclusively in lower limbs (34.8%). Conclusions Differences in clinical and epidemiological presentation were found between SL patients as compared to CL ones, in a region with a known predominance of Leishmania (Viannia) braziliensis. The results are similar to the features of most of the sporotrichosis patients as described in literature, making the differential diagnosis between ATL and sporotrichosis more important in overlapping areas for both diseases, like in Rio de Janeiro State

Ensaio Imunoenzimático com Antígeno de Leishmania (Viannia) braziliensis no Diagnóstico e Acompanhamento de Pacientes com Leishmaniose Tegumentar Americana

Made available in DSpace on 2016-05-16T12:53:22Z (GMT). No. of bitstreams: 2 eliame_confort_ipec_dout_2009.pdf: 1662597 bytes, checksum: 2845404a7d2a515a0ca6f5220b3ccd21 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2009Fundação Oswaldo Cruz. Instituto Nacional de Infectologia Evandro Chagas. Rio de Janeiro, RJ, BrasilAvaliou-se o ensaio imunoenzimático indireto (ELISA) com antígeno de Leishmania (V.) braziliensis para a investigação diagnóstica da leishmaniose tegumentar americana (LTA) em suas modalidades cutânea (LC) e cutâneomucosa (LCM) e avaliação da resposta terapêutica a partir de amostras de soro de pacientes atendidos no Instituto de Pesquisa Clínica Evandro Chagas (IPEC). O grupo I, LTA (n=153) foi formado com amostras de soros de pacientes com pelo menos um resultado positivo nos exames parasitológicos ou na reação em cadeia da polimerase (PCR), e o grupo II, controle (n=103), com amostras de indivíduos representativos da população do estudo, com suspeita inicial de LTA, mas com outro diagnóstico confirmado. As seguintes informações foram obtidas dos prontuários: avaliação clínica, dermatológica otorrinolaringológica; intradermorreação de Montenegro IDRM; pesquisa de Leishmania por exame direto e histopatológico, isolamento em meio de cultura, PCR e exames diretos com colorações especiais, inoculação em meios de cultura para fungos e micobactérias. As amostras foram obtidas nas fases de investigação diagnóstica e pós-tratamento em períodos definidos até dois anos. Comparou-se a sensibilidade do ELISA com a de cada um dos métodos parasitológicos, PCR e com a IDRM. Para avaliação da resposta terapêutica, amostras de 75 pacientes que se mantiveram com as lesões cicatrizadas durante o período do estudo constituíram o subgrupo cura terapêutica (ICT) e aquelas de 31 pacientes com recidivas constituíram o subgrupo recidiva pósterapêutica (IRT). A confiabilidade do teste avaliado pelo coeficiente de correlação intraclasse foi de 0,953 (IC 95%) Encontrou-se sensibilidade de 94,7%, especificidade de 95,1% e valores preditivos, positivo e negativo de 96,6% e 92,4% respectivamente. Não houve diferença com significância estatística entre as sensibilidades encontradas no ELISA, na PCR e na IDRM (CI= 95%, qui-quadrado pvalor= 0,140 e p-valor=0,498). O mesmo não ocorreu com os demais métodos parasitológicos (p-valor<0,001). A análise da resposta humoral à terapia demonstrou haver redução da resposta de anticorpos nos pacientes do subgrupo ICT significativamente menor aos seis meses após o tratamento (Wilcoxon; pvalor= 0,016) com 51,8% de pacientes não reatores ao final de dois anos após a terapia. Os demais se encontravam fracamente reatores. Ao contrário, no subgrupo IRT, houve pequena redução seguida de elevação dos valores de densidade otica atingindo patamares mais elevados na ocasião da recidiva. Comparando-se estes subgrupos (ICT e IRT) quanto à intensidade das reações e frequencia de reatores, em cada ponto do acompanhamento, encontraram-se diferenças a partir do sexto mês após a terapia e a cura clínica (Mann-Whitney; p-valor=0,046 e p-valor 0,009). Os resultados demonstram um bom desempenho do ELISA no diagnóstico diferencial de LTA e na avaliação da resposta terapêuticaIndirect Enzyme Immunoassay (EL ISA) was evaluated with Leishmania (V.) braziliensis antigen to the diagnostic workup of American Tegumentary Leishmaniasis (American Tegumentary Leishmaniasis - ATL ) in their cutaneous (CL) and mucocutaneous (MCL) modalities, and about the therapeutic res ponse from samples of serum from patients at the Instituto de Pesquisa Clínica Evandro Chagas (IPEC). Group I , ACL (n = 153) was formed with sera samples of patients with at least one positive result in parasitological examinations or in polymerase chain r eaction (PCR), and group II , control (n = 103), with samples of individuals representative of the study population, with initial suspicion of ACL, but with other confirmed diagnosis. The following information was obtained from medical records: clinical, de rmatological, and otorrinolaringology evaluation; measure in mm of Montenegro intradermoreaction (IDRM); search for Leishmania by direct examination and histopathology, isolation in culture media, PCR and direct examination with special staining and inocul ation in culture media for fungi and mycobacteria. Samples were obtained during the diagnostic workup and after treatment, in periods defined as up to two years. We compared the sensitivity of the ELISA with each of the individual parasitological methods, the PCR, and the IDRM. To evaluate the therapeutic response, samples of 75 patients who remained with the lesions healed during the study period were the therapeutic healing subgroup ( ICT ) and those 31 patients with recurrences were the post - therapy relaps e subgroup ( IRT ). The reliability of the test assessed by the intraclass correlation coefficient was 0.953 (95% CI). We found a sensitivity of 94.7% and 95.1% specificity, and positive and negative predictive values of 96.6% and 92.4%, respectively. There was no statistically significant difference between the sensitivities found in ELISA, PCR and IDRM (95% CI, Chi - square p - value = 0.140 and p - value = 0.498). The same did not happen with the remainder parasitological methods ( p - value <0.001). The analysis o f the humoral response to therapy have demonstrated a decrease of the antibody response in patients of subgroup ICT , significantly lower at six months after treatment (Wilcoxon; p - value = 0.016), with 51.8% of patients non reactors at the end of two years after the therapy. The others remained mild reactors. Contrarily, in subgroup IRT, a small reduction of the intensity of the reactions, was followed by the increase in the values of optical density that reached higher levels during recidive. Analyzed toget her, the results of samples from the IRT subgroup were significantly higher than those from the ICT subgroup (Mann - Whitney; p - value <0.0001). The intensity of reactions and the frequency of reactors there were reduce from the six months after the therapia sustaining this thendency afther the clinical cure. When comparing the intensity of reactions and frequency of reactors in each point of follow - up there were differences from the sixth month of therapy and clinical cure (Mann - Whitney; p - value = 0.046 and p - value 0.009). The results show a good performance of the ELISA in the differential diagnosis of ACL and the assessment of therapeutic response