BackgroundMiltefosine has been used successfully to treat visceral leishmaniasis (VL) in India, but it was unsuccessful for VL in a clinical trial in Brazil.MethodsTo identify molecular markers that predict VL treatment failure whole genome sequencing of 26 L. infantum isolates, from cured and relapsed patients allowed a GWAS analysis of SNPs, gene and chromosome copy number variations.FindingsA strong association was identified (p = 0·0005) between the presence of a genetically stable L. infantumMiltefosine Sensitivity Locus (MSL), and a positive response to miltefosine treatment. The risk of treatment failure increased 9·4-fold (95% CI 2·11–53·54) when an isolate did not have the MSL. The complete absence of the MSL predicted miltefosine failure with 0·92 (95% CI 0·65–0·996) sensitivity and 0·78 (95% CI 0·52–0·92) specificity. A genotyping survey of L. infantum (n = 157) showed that the frequency of MSL varies in a cline from 95% in North East Brazil to <5% in the South East. The MSL was found in the genomes of all L. infantum and L. donovani sequenced isolates from the Old World (n = 671), where miltefosine can have a cure rate higher than 93%.InterpretationKnowledge on the presence or absence of the MSL in L. infantum will allow stratification of patients prior to treatment, helping to establish better therapeutic strategies for VL treatment.FundCNPq, FAPES, GCRF MRC and Wellcome Trust.

Abstract. There are no recognized orally administered treatments for any of the leishmaniases. The 8-aminoquinoline WR6026 is an orally administered analog of primaquine that cured 50% of patients with kala-azar in Kenya at a dose of 1 mg/kg/day for 28 days. A further phase 2, open-label, dose-escalating safety and efficacy study was performed for kala-azar in Brazil. Cure rates for Brazilian patients treated for 28 days were as follows: 1 mg/kg/day: 0 of 4 (0%); 1.5 mg/kg/day: 1 of 6 (17%); 2.0 mg/kg/day: 4 of 6 (67%); 2.5 mg/kg/day: 1 of 5 (20%); and 3.25 mg/ kg/day: 0 of 1 (0%). Nephrotoxicity that was not anticipated from preclinical animal studies or from phase 1 studies was seen at 2.5 mg/kg/day in 2 patients and in the single patient administered 3.25 mg/kg/day. WR6026 demonstrated the unusual clinical features of lack of increased efficacy against Brazilian kala-azar with increased dosing above 2 mg/kg/day and toxicity that was not present in previous investigations.

O objetivo deste estudo foi descrever o perfil epidemiológico dos acidentes ofídicos da macrorregião de saúde do Norte do Estado de Minas Gerais, Brasil. Foram analisadas informações sobre os acidentes ofídicos relativos ao período compreendido entre janeiro de 2002 a dezembro de 2006, por meio de bancos de dados. Os resultados demonstraram 10.553 casos notificados, com ênfase para a maior casuística em meses de tempo quente e chuvoso, em áreas urbanas (54,1%), faixa etária menor de 20 anos (39,7%), acometendo mais homens e estudantes (53,1% e 29,1%) respectivamente. Os membros inferiores (pé, dedo do pé, perna e coxa) foram os locais mais afetados (35,9%), as serpentes prevalentes foram do gênero Bothrops (82,9%) e a gravidade da maioria dos acidentes foi leve (66,2%). Observou-se nesse estudo um importante impacto da sazonalidade, urbanização, subnotificação das espécies envolvidas nesses acidentes e busca rápida pelo pronto atendimento. Espera-se que os dados inéditos da casuística obtida possam servir de substrato para o planejamento e execução de medidas voltadas para vigilância em saúde e atendimento.

BackgroundThere is insufficient evidence to support visceral leishmaniasis (VL) treatment recommendations in Brazil and an urgent need to improve current treatments. Drug combinations may be an option.MethodsA multicenter, randomized, open label, controlled trial was conducted in five sites in Brazil to evaluate efficacy and safety of (i) amphotericin B deoxycholate (AmphoB) (1 mg/kg/day for 14 days), (ii) liposomal amphotericin B (LAMB) (3 mg/kg/day for 7 days) and (iii) a combination of LAMB (10 mg/kg single dose) plus meglumine antimoniate (MA) (20 mg Sb+5/kg/day for 10 days), compared to (iv) standard treatment with MA (20 mg Sb+5/kg/day for 20 days). Patients, aged 6 months to 50 years, with confirmed VL and without HIV infection were enrolled in the study. Primary efficacy endpoint was clinical cure at 6 months. A planned efficacy and safety interim analysis led to trial interruption.Results378 patients were randomized to the four treatment arms: MA (n = 112), AmphoB (n = 45), LAMB (n = 109), or LAMB plus MA (n = 112). A high toxicity of AmphoB prompted an unplanned interim safety analysis and this treatment arm was dropped. Per intention-to-treat protocol final analyses of the remaining 332 patients show cure rates at 6 months of 77.5% for MA, 87.2% for LAMB, and 83.9% for LAMB plus MA, without statistically significant differences between the experimental arms and comparator (LAMB: 9.7%; CI95% -0.28 to 19.68, p = 0.06; LAMB plus MA: 6.4%; CI95% -3.93 to 16.73; p = 0.222). LAMB monotherapy was safer than MA regarding frequency of treatment-related adverse events (AE) (p = 0.045), proportion of patients presenting at least one severe AE (p = 0.029), and the proportion of AEs resulting in definitive treatment discontinuation (p = 0.003).ConclusionsDue to lower toxicity and acceptable efficacy, LAMB would be a more suitable first line treatment for VL than standard treatment. ClinicalTrials.gov identification number: NCT01310738.Trial registrationClinicalTrials.gov NCT01310738

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In India, visceral leishmaniasis (VL) caused by Leishmania donovani has been successfully treated with miltefosine with a cure rate of > 90%. To assess the efficacy and safety of oral miltefosine against Brazilian VL, which is caused by Leishmania infantum, a phase II, open-label, dose-escalation study of oral miltefosine was conducted in children (aged 2-12 years) and adolescent-adults (aged 13-60 years). Definitive cure was assessed at a 6-month followup visit. The cure rate was only 42% (6 of 14 patients) with a recommended treatment of 28 days and 68% (19 of 28 patients) with an extended treatment of 42 days. The in vitro miltefosine susceptibility profile of intracellular amastigote stages of the pretreatment isolates, from cured and relapsed patients, showed a positive correlation with the clinical outcome. The IC 50 mean (SEM) of eventual cures was 5.1 (0.4) μM, whereas that of eventual failures was 12.8 (1.9) μM (P = 0.0002). An IC 50 above 8.0 μM predicts failure with 82% sensitivity and 100% specificity. The finding of L. infantum amastigotes resistant to miltefosine in isolates from patients who eventually failed treatment strongly suggests natural resistance to this drug, as miltefosine had never been used in Brazil before this trial was carried out.

The search toward the establishment of novel serological tests for the diagnosis of leishmaniasis and proper differential diagnosis may represent one alternative to the invasive parasitological methods currently used to identify infected individuals. In the present work, we investigated the potential use of recombinant peroxidoxin (rPeroxidoxin) of Leishmania (Viannia) braziliensis as a potential antigen for the immunodiagnosis of human tegumentary (TL) and visceral leishmaniasis (VL) and canine visceral leishmaniasis (CVL). Linear B-cell epitope mapping was performed to identify polymorphic epitopes when comparing orthologous sequences present in Trypanosoma cruzi, the agent for Chagas disease (CD), and the Homo sapiens and Canis familiaris hosts. The serological assay (ELISA) demonstrated that TL, VL and CVL individuals showed high levels of antibodies against rPeroxidoxin, allowing identification of infected ones with considerable sensitivity and great ability to discriminate (specificity) between non-infected and CD individuals (98.46% and 100%; 98.18% and 95.71%; 95.79% and 100%, respectively). An rPeroxidoxin ELISA also showed a greater ability to discriminate between vaccinated and infected animals, which is an important requirement for the public campaign control of CVL. A depletion ELISA assay using soluble peptides of this B-cell epitope confirmed the recognition of these sites only by Leishmania-infected individuals. Moreover, this work identifies two antigenic polymorphic linear B-cell epitopes of L. braziliensis. Specific recognition of TL and VL patients was confirmed by significantly decreased IgG reactivity against rPeroxidoxin after depletion of peptide-1- and peptide-2-specific antibodies (peptide 1: reduced by 32%, 42% and 5% for CL, ML and VL, respectively; peptide-2: reduced by 24%, 22% and 13% for CL, ML and VL, respectively) and only peptide-2 for CVL (reduced 9%). Overall, rPeroxidoxin may be a potential antigen for the immunodiagnosis of TL, VL or CVL, as it has a higher agreement with parasitological assays and is better than other reference tests that use soluble Leishmania antigens for diagnosing CVL in Brazil (EIE-LVC, Bio-manguinhos, FIOCRUZ).

Visceral leishmaniasis (VL) is a serious disease with a challenging treatment plan requiring the prolonged and painful applications of poorly tolerated toxic drugs. Therefore, the identification of miltefosine, an effective and safe oral drug, was considered a significant advancement in leishmaniasis therapy. However, different sensitivities to miltefosine in Leishmania have been observed in clinically relevant species, and the biological mechanism by which clinical isolates of Leishmania acquire drug resistance is poorly understood. Our work aims to elucidate the mechanism of natural resistance to miltefosine in Leishmania by studying the isolates from VL patients who displayed different miltefosine treatment outcomes.