Use of PCR in diagnosis of human american tegumentary leishmaniasis in Rio de Janeiro, Brazil.
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In Brazil, the most common etiological agent of American tegumentary leishmaniasis is Leishmania (Viannia) braziliensis. In general, diagnostic techniques envisage the visualization of the parasite, but that technique has a low sensitivity. The main purpose of the present work was to evaluate the PCR as a routine tool for the diagnosis of leishmaniasis. Biopsy specimens from cutaneous or mucosal lesions were taken from 230 individuals from areas where Leishmania is endemic: 216 patients who had a clinical picture suggestive of leishmaniasis and 14 individuals with cutaneous lesions due to other causes. Each specimen was processed for histopathologic examination, culture, touch preparation, and DNA isolation. Oligonucleotides that amplify the conserved region of the minicircle molecules of Leishmania were used in a hot-start PCR. While at least one conventional technique was positive for Leishmania for 62% (134 of 216) of the patients, PCR coupled to hybridization was positive for 94% (203 of 216) of the patients. The 14 patients whose clinical picture was not suggestive of leishmaniasis had negative results by all techniques. The impact of the PCR was striking in mucosal disease. While the disease in only 17% (4 of 24) of the patients could be diagnosed by conventional techniques, PCR was positive for 71% (17 of 24) of the patients. Hybridization showed that all cases of disease were caused by parasites belonging to the Viannia subgenus. Altogether, the results indicate that PCR is a valuable tool for the diagnosis of leishmaniasis on a routine basis and is likely to provide valuable epidemiological information about the disease in countries where it is endemic. (+info)
Sensitivity of a vacuum aspiratory culture technique for diagnosis of localized cutaneous leishmaniasis in an endemic area of Leishmania (Viannia) braziliensis transmission.
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Sixty eight patients with localized cutaneous leishmaniasis from an area with Leishmania (Viannia) braziliensis transmission had cultures performed with a modified Marzochis vacuum aspiratory puncture technique to establish sensitivity and contamination rate with this new method. Overall sensitivity of three aspirates was 47.1%; (CI95% 39.4; 59.4) significantly greater than the sensitivity of a single one aspirate. Fungal contamination was observed in 6/204 (2.9%) inoculated culture tubes. We recommend that this useful technique should be adopted as routine for primary isolation of L. (V.) braziliensis from localized cutaneous ulcers. (+info)
Sensitivity of lymph node aspiration in localized cutaneous leishmaniasis due to Leishmania (Viannia) braziliensis.
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Twenty nine patients with localized cutaneous leishmaniasis had lymph node and skin ulcer aspirations for culture of Leishmania with the modified Marzochis vacuum aspiratory technique. Sensitivity of lymph node aspiration was 58.6% and 34.5% for skin ulcer aspiration (P=0.06). Combined sensitivity of the two methods was 79.3%. There was no agreement between methods (Kappa Index = -0.084; CI95% -0,45; 0,28) showing the potential complementary roles in diagnostic approach. (+info)
Atypical mucocutaneous leishmaniasis caused by Leishmania braziliensis in an acquired immunodeficiency syndrome patient: T-cell responses and remission of lesions associated with antigen immunotherapy.
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An atypical case of acquired immunodeficiency syndrome-associated mucocutaneous lesions due to Leishmania braziliensis is described. Many vacuolated macrophages laden with amastigote forms of the parasite were found in the lesions. Leishmanin skin test and serology for leishmaniasis were both negative. The patient was resistant to therapy with conventional drugs (antimonial and amphotericin B). Interestingly, remission of lesions was achieved after an alternative combined therapy of antimonial associated with immunotherapy (whole promastigote antigens). Peripheral blood mononuclear cells were separated and stimulated in vitro with Leishmania antigens to test the lymphoproliferative responses (LPR). Before the combined immunochemotherapy, the LPR to leishmanial antigens was negligible (stimulation index - SI=1.4). After the first course of combined therapy it became positive (SI=4.17). The antigen responding cells were predominantly T-cells (47.5%) most of them with CD8+ phenotype (33%). Very low CD4+ cells (2.2%) percentages were detected. The increased T-cell responsiveness to leishmanial antigens after combined therapy was accompanied by interferon-g (IFN-g) production as observed in the cell culture supernatants. In this patient, healing of the leishmaniasis lesions was associated with the induction of a specific T-cell immune response, characterized by the production of IFN-g and the predominance of the CD8+ phenotype among the Leishmania-reactive T-cells. (+info)
Experimental infection of canine peritoneal macrophages with visceral and dermotropic Leishmania strains.
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A study was carried out using macrophages cultured from the peritoneal exudate of dogs infected in vitro with three species of Leishmania: L. (L.) chagasi, L. (Viannia) braziliensis and L. (L.) amazonensis with the aim of investigating the growth kinetics and infectivity of these species in the host cell. Results were expressed as the percentage of macrophages infected measured at 24 hr intervals over six days in RPMI - 1640 culture medium at a temperature of 34-35 degrees C. The findings open the possibility of using canine peritoneal cells as a model for the screening of leishmanicide drugs and to study the pathogenesis of these species. (+info)
Down-regulation of Th1 type of response in early human American cutaneous leishmaniasis.
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This study examined the T cell responses in the early phase of Leishmania braziliensis infection. Cytokine profiles, lymphoproliferative responses, and skin test results in 25 patients with early cutaneous leishmaniasis (ECL; illness duration <60 days) were compared with those in persons with late cutaneous leishmaniasis (LCL; illness duration >2 months). Absent or low lymphoproliferative responses were observed in 8 (32%) of 25 patients and an absence of interferon (IFN)-gamma production in 9 (41%) of 22 patients prior to therapy. IFN-gamma production in ECL (mean +/- SD) was lower than in LCL (293+/-346 vs. 747+/-377 pg/mL, respectively; P<.01). In contrast, interleukin (IL)-10 production in ECL (mean +/- SD) was higher than in LCL (246+/-56 vs. 50+/-41 pg/mL, respectively; P<.01). Restoration of lymphoproliferative responses and IFN-gamma production was achieved when monoclonal antibody to IL-10 or IL-12 was added to the cultures. These results show that T cell responses during early-phase infection are down-regulated by IL-10 and may facilitate parasite multiplication. (+info)
Out-patient parenteral antimicrobial therapy--a viable option for the management of cutaneous leishmaniasis.
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Cutaneous infection with Leishmania braziliensis complex requires treatment with parenteral pentavalent antimonials to prevent development of mucocutaneous leishmaniasis. Patients with imported disease are usually managed in hospital because of concerns over drug toxicity. This study describes the clinical features and outcome of infection treated in the UK in an out-patient setting. Thirteen marines (aged 19-35 years) who acquired leishmaniasis in Belize were studied prospectively. Three had at least two lesions (0. 6-3 cm diameter), eight had regional lymphadenopathy and one had localized painless lymphatic thickening. Histology for amastigotes and PCR for Leishmania braziliensis complex was positive in all. Culture was positive in six. Patients received 1.5-2 g (mean 1.7 g) (20 mg/kg) sodium stibogluconate intravenously daily for 20 days. All developed transient musculoskeletal symptoms and asymptomatic hepatitis. Eleven developed biochemical pancreatitis, and one thrombocytopenia. Three developed transient ECG changes and one herpes zoster. There were four device-related infections, two requiring hospitalization (one required surgical drainage of an abscess). All lesions re-epithelialized. A total of 250 bed-days were saved over a 67-day period. These results indicate that in selected patients, out-patient therapy for cutaneous leishmaniasis with parenteral high-dose sodium stibogluconate may be appropriate, provided there is adequate monitoring of therapy. (+info)
Is the domestic dog (Canis familiaris) a reservoir host of American cutaneous leishmaniasis? A critical review of the current evidence.
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Originally associated with forested areas, the transmission cycle of American cutaneous leishmaniasis (ACL) has now adapted to the domestic environment in at least 9 Latin American countries. Several studies have suggested that the domestic dog (Canis familiaris), which is already incriminated as the primary reservoir host of zoonotic visceral leishmaniasis (ZVL), may have a reservoir role in the domestic transmission of human ACL caused by Leishmania braziliensis, L. panamensis, and L. peruviana. This article reviews more than 90 studies reporting ACL infections in dogs, and concludes that as yet there is only circumstantial evidence to support that claim. Almost no data are available on the infectiousness of dogs to sandfly vectors of ACL, and there are few indications that either dog ownership or dog abundance are risk factors for ACL. Nevertheless, it has been proposed that incidence of ACL in humans could be reduced by targeting infected dogs. While this control strategy has been used for many decades against ZVL in Latin America, Europe, and Asia, there is little evidence to demonstrate its effectiveness either in theory or in practice. Particular concerns over the sensitivity and specificity of diagnostic tools, low compliance rates among dog owners, and cost-effectiveness are likely to apply equally to ACL control. (+info)