RESUMO
Comparative ELISA and selective immunoblotting procedures were used in attempts to identify differential serological indicators of infection with the Leishmania (Viannia) braziliensis complex, infection with the L. braziliensis species, and therapeutic cure of localized or mucocutaneous leishmaniasis (LCL or MCL). Although mean ELISA absorbance values were significantly higher for MCL sera than for LCL sera, absorbance could not be used as a reliable indicator of the clinical form of disease. Immunoblotting profiles were similar with sera from MCL and LCL. Pre-adsorption with heterologous trypanosomatid antigens indicated that recognition of antigens of about 56, 60, 66, 72, 88 and 110 kDa might be specific to the subgenus Viannia. In two-colour, sequential, dual ELISA-based immunoblotting, no antigens recognized only by sera from MCL patients were detected. After glucantime therapy, immunoblotting profiles with LCL sera were reduced both in intensity and in the range of antigens detected; a 104-kDa antigen was newly detected with post-treatment LCL sera. Overall, the results show the value of differential immunological detection strategies and support the close relationship between species of the subgenus Viannia but fail to indicate a prognostic antigen for MCL.
Assuntos
Antígenos de Protozoários/imunologia , Leishmania braziliensis/imunologia , Leishmaniose Mucocutânea/imunologia , Animais , Antígenos de Protozoários/efeitos dos fármacos , Antiprotozoários/uso terapêutico , Biomarcadores/sangue , Western Blotting , Estudos de Casos e Controles , Reações Cruzadas , Ensaio de Imunoadsorção Enzimática , Humanos , Leishmania braziliensis/efeitos dos fármacos , Leishmaniose Mucocutânea/tratamento farmacológico , Meglumina/uso terapêutico , Antimoniato de Meglumina , Compostos Organometálicos/uso terapêuticoRESUMO
A Leishmania donovani-complex specific DNA probe was usedto confirm the widespread dissemination of amastigotes in apparently normal skinof dogs with canine visceral leishmaniasis. When Lutzomyia longipalpis were fed on abnormal skin of five naturally infected dogs 57 of 163 (35 per cent) fliesbecame infected: four of 65 flies (6 per cent) became infected when fed on apparently normal skin. The bite of a single sandfly that had fed seven days previouslyon a naturally infected dog transmitted the infection to a young dog from a non-endemic area. Within 22 days a lesion had developed at the site of the infectivebite (inner ear): 98 days after infection organisms had not disseminated throughout the skin, bone marrow, spleen or liver and the animal was still serologically negative by indirect immunofluorescence and dot-enzyme-linked immunosorbent assay. When fed Lu. longipalpis were captured from a kennel with a sick dog known to be infected, 33 out of 49 (67 per cent) of flies contained promastigotes. In contrast only two infections were detected among more than 200 sandflies captured in houses. These observations confirm the ease of transmissibility of L.chagasi from dog to sandfly to dog in Teresina. It is likely that canine VL is the major source of human VL by the transmission route dog-sandfly-human. the Lmet2 DNA probe was a useful epidemiological tool for detecting L. chagasi in sandflies
Assuntos
Humanos , Animais , Cães , Doenças do Cão/transmissão , Leishmaniose Visceral/veterinária , Psychodidae/parasitologia , Sondas de DNA , Mordeduras e Picadas de Insetos/complicações , Leishmania donovani/genética , Leishmaniose Visceral/transmissão , Pele/parasitologiaRESUMO
A Leishmania donovani-complex specific DNA probe was used to confirm the widespread dissemination of amastigotes in apparently normal skin of dogs with canine visceral leishmaniasis. When Lutzomyia longipalpis were fed on abnormal skin of five naturally infected dogs 57 of 163 (35%) flies became infected: four of 65 flies (6%) became infected when fed on apparently normal skin. The bite of a single sandfly that had fed seven days previously on a naturally infected dog transmitted the infection to a young dog from a non-endemic area. Within 22 days a lesion had developed at the site of the infective bite (inner ear): 98 days after infection organisms had not disseminated throughout the skin, bone marrow, spleen or liver and the animal was still serologically negative by indirect immunofluorescence and dot-enzyme-linked immunosorbent assay. When fed Lu. longipalpis were captured from a kennel with a sick dog known to be infected, 33 out of 49 (67%) of flies contained promastigotes. In contrast only two infections were detected among more than 200 sandflies captured in houses. These observations confirm the ease of transmissibility of L. chagasi from dog to sandfly to dog in Teresina. It is likely that canine VL is the major source of human VL by the transmission route dog-sandfly-human. The Lmet2 DNA probe was a useful epidemiological tool for detecting L. chagasi in sandflies.
Assuntos
Doenças do Cão/transmissão , Leishmaniose Visceral/veterinária , Psychodidae/parasitologia , Animais , Sondas de DNA , Cães , Humanos , Mordeduras e Picadas de Insetos/complicações , Leishmania donovani/genética , Leishmaniose Visceral/transmissão , Pele/parasitologiaRESUMO
The Lmet2 chemiluminescent DNA probe is a valuable tool for identifying parasites of the Leishmania donovani -complex in sand flies, dogs and human samples. Recent blood meals in sand flies or blood contamination of tissue samples inhibited probe sensitivity, whether radiolabelled or chemiluminescent detection systems were used. Treatment of membranes with protease before hybridisation restored positive signal. Alternatively samples could be lysed with protease and applied to membranes with a vacuum blotting apparatus. The Lmet2 protocol provides the basis for a DNA probe kit that is adaptable for use with a wide range of other probes.
Assuntos
Sondas de DNA , DNA de Protozoário , Doenças do Cão/patologia , Insetos Vetores/parasitologia , Leishmania infantum/genética , Leishmaniose Visceral/patologia , Psychodidae/parasitologia , Kit de Reagentes para Diagnóstico/normas , Manejo de Espécimes/métodos , Animais , Viés , Biópsia , Protocolos Clínicos , Modelos Animais de Doenças , Cães , Endopeptidases , Estudos de Avaliação como Assunto , Leishmania donovani , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
The enzyme linked immunosorbent assay (ELISA) was used to analyse 4372 blood samples from residents of 978 households in 20 representative communities in the Mexican state of Guerrero. Seventy-five individuals had very high titres of antibodies against Trypanosoma cruzi. Samples with intermediate optical density values, despite overlapping values with several control positives on a single-well test, did not sustain their positivity at high dilutions. 'Intermediate positives' had a different distribution among the 20 communities to samples sustaining reactivity at high dilutions, indicating possible cross-reactivity with another infectious agent. The finding of seropositive children under the age of 10 years in the Costa Chica, Acapulco and the Tierra Caliente regions, with family clustering of putative cases, indicates that recent transmission must be considered. Very few people interviewed in the 20 communities knew the triatomine bug could transmit a disease.