Search

Leishmaniases are zoonotic diseases caused by protozoa of the genus Leishmania. In Bolivia, leishmaniasis occurs mainly in the cutaneous form (CL) followed by the mucosal or mucocutaneous form (ML or MCL), grouped as tegumentary leishmaniosis (TL), while cases of visceral leishmaniasis (VL) are rare. The cases of TL are routinely diagnosed by parasitological methods: Direct Parasitological Exam (DPE) and axenic culture, the latter being performed only by specialized laboratories. The aim of the present study was to optimize the parasitological diagnosis of TL in Bolivia, using two sampling methods. Samples from 117 patients with suspected TL, obtained by aspiration (n = 121) and scraping (n = 121) of the edge of the lesion were tested by: direct parasitological exam, culture in TSTB medium, and miniculture and microculture in Schneider's medium. A positive laboratory result by any of the four techniques evaluated using either of the two sampling methods was considered the gold standard. Of the 117 suspected patients included, TL was confirmed in 96 (82 %), corresponding 79 of the confirmed cases (82.3 %) to CL and 16 (16.7 %) to ML. Parasitological techniques specificity was 100 % and their analytical sensitivity was greater with scraping samples in TSTB culture (98 %). Scraping samples in TSTB and miniculture correlated well with the reference (Cohen's kappa coefficient=0.88) and showed good reliability (Cronbach's alpha coefficient ≥0.91). Microculture provided positive results earlier than the other culture methods (mean day 4.5). By day 14, 98 % of positive cultures had been detected. Scraping sampling and miniculture were associated with higher culture contamination (6 % and 17 %, respectively). Bacterial contamination predominated, regardless of the sampling and culture method, while filamentous fungi and mixed contamination were more frequently observed in cultures from scraping samples. In conclusion: (i) scraping samples proved more suitable for the diagnosis of TL as they increased analytical sensitivity, are less traumatic for the patient and are safer for laboratory personnel than aspirates; (ii) culture, mainly in TSBT medium, should be used for the diagnosis of TL due to its high sensitivity (doubling the number of cases diagnosed by DPE) and its low cost compared to other culture media., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Background: Treatment guidance for children and older adult patients affected by cutaneous leishmaniasis (CL) is unclear due to limited representation of these groups in clinical trials., Methods: We conducted a collaborative retrospective study to describe the effectiveness and safety of antileishmanial treatments in children ≤ 10 and adults ≥ 60 years of age, treated between 2014 and 2018 in ten CL referral centers in Latin America., Results: 2,037 clinical records were assessed for eligibility. Of them, the main reason for non-inclusion was lack of data on treatment follow-up and therapeutic response (182/242, 75% of children and 179/468, 38% of adults). Data on 1,325 eligible CL patients (736 children and 589 older adults) were analyzed. In both age groups, disease presentation was mild, with a median number of lesions of one (IQR: 1-2) and median lesion diameter of less than 3 cm. Less than 50% of the patients had data for two or more follow-up visits post-treatment (being only 28% in pediatric patients). Systemic antimonials were the most common monotherapy regimen in both age groups (590/736, 80.2% of children and 308/589, 52.3% of older adults) with overall cure rates of 54.6% (95% CI: 50.5-58.6%) and 68.2% (95% CI: 62.6-73.4%), respectively. Other treatments used include miltefosine, amphotericin B, intralesional antimonials, and pentamidine. Adverse reactions related to the main treatment were experienced in 11.9% (86/722) of children versus 38.4% (206/537) of older adults. Most adverse reactions were of mild intensity., Conclusion: Our findings support the need for greater availability and use of alternatives to systemic antimonials, particularly local therapies, and development of strategies to improve patient follow-up across the region, with special attention to pediatric populations., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Castro et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: Tegumentary leishmaniasis (TL) is a parasitic disease that can present a cutaneous or mucocutaneous clinical form (CL and MCL, respectively). The disease is caused by different Leishmania species and transmitted by phlebotomine sand flies. Bolivia has one of the highest incidences of the disease in South America and the diagnosis is done by parasitological techniques. Our aim was to describe the clinical and immunological characteristics of CL and MCL patients attending the leishmaniasis reference center in Cochabamba, Bolivia, in order to gain updated clinical and epidemiological information, to evaluate the diagnostic methods used and to identify biomarkers related to clinical disease and its evolution., Methodology/principal Findings: The study was conducted from September 2014 to November 2015 and 135 patients with lesions compatible with CL or MCL were included. Epidemiological and clinical data were collected using a semi-structured questionnaire. Two parasitological diagnostic methods were used: Giemsa-stained smears and culture of lesion aspirates. Blood samples obtained from participants were used to measure the concentrations of different cytokines. 59.2% (80/135) were leishmaniasis confirmed cases (CL: 71.3%; MCL: 28.7%). Sixty percent of the confirmed cases were positive by smears and 90.6% were positive by culture. 53.8% were primo-infections. Eotaxin and monokine induced by IFN-γ presented higher serum concentrations in the MCL clinical presentation compared to CL cases and no-cases. None of the cytokines presented different concentrations between primo-infections and secondary infections due to treatment failure., Conclusions/significance: In Bolivia, parasitological diagnosis remains the reference standard in diagnosis of leishmaniasis because of its high specificity, whereas the sensitivity varies over a wide range leading to loss of cases. Until more accurate tools are implemented, all patients should be tested by both smears and culture of lesion aspirates to minimize the risk of false negatives. Our results showed higher concentrations of several cytokines in MCL compared to CL, but no differences were observed between CL and no-cases. In addition, none of the cytokines differed between primary and secondary infections. These results highlight the need of further research to identify biomarkers of susceptibility and disease progression, in addition to looking at the local cellular immune responses in the lesions., Competing Interests: The authors have declared that no competing interests exist.

This study evaluates the level of underreporting of the National Program of Leishmaniasis Control (NPLC) in two communities of Cochabamba, Bolivia during the period 2013-2014. Montenegro skin test-confirmed cases of cutaneous leishmaniasis (CL) were identified through active surveillance during medical campaigns. These cases were compared with those registered in the NPLC by passive surveillance. After matching and cleaning data from the two sources, the total number of cases and the level of underreporting of the National Program were calculated using the capture-recapture analysis. This estimated that 86 cases of CL (95% confidence interval [CI]: 62.1-110.8) occurred in the study period in both communities. The level of underreporting of the NPLC in these communities was very high: 73.4% (95% CI: 63.1-81.5%). These results can be explained by the inaccessibility of health services and centralization of the NPLC activities. This information is important to establish priorities among policy-makers and funding organizations as well as implementing adequate intervention plans.

Cutaneous leishmaniasis triggers a varied immune response depending on parasite and host factors, which in turn can be influenced by nutrients. The resistance to the infection is associated with the Th1 type of cytokine production. The Th1 type can be reduced as a consequence of zinc deficiency, which may increase the risk for chronicity of the infection. Using in vitro and ex vivo models, we studied the influence of zinc supplementation on the immune response in patients with cutaneous leishmaniasis treated with antimony and the data were also compared to those of matched controls. Twenty-nine patients with cutaneous leishmaniasis (n=14 in zinc-supplemented group [45mg/day] and n=15 in placebo group) were treated by intramuscular injections of antimony for 20 days and took supplements for 60 days. Immunoglobulins in plasma and cell proliferation, IFN-γ production and CD markers of isolated peripheral blood mononuclear cells (PBMC) were measured. It was found that the cellular immune response of the patients maintained its activity as assessed by the ability of the PBMC to proliferate and produce IFN-γ in response to concanavalin A. Moreover, there was no difference in these variables between the zinc-supplemented and placebo groups after 60 days. The addition of zinc sulphate in vitro to PBMC reduced the IFN-γ production in the placebo group only. It is concluded that the cellular immune response of the cutaneous leishmaniasis patients remained active during treatment by antimony when compared to that of controls. It was not possible to document an additional effect of zinc supplementation for 60 days on the immune response., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Background: Cutaneous leishmaniasis is an ultimately self-curing disease for which systemic therapy with pentavalent antimony (Sb) is effective but with side effects. We evaluated 2 local treatments, intralesional (IL) Sb and cryotherapy, for single lesions due to Bolivian Leishmania (v.) braziliensis in a placebo-controlled study., Methods: Patients were randomized between IL Sb (650 µg/mm(2) of lesion area on days 1, 3, and 5), cryotherapy (days 1 and 14), and placebo cream (daily for 20 days) in a 3:2:3 allocation. Lesion area was measured prior to therapy, and at 1, 3, and 6 months after therapy. The criteria for lesion cure were as follows: not doubling in size at 1 month, at least 50% diminution in size at 3 months, and complete reepithelialization at 6 months. Local adverse effects were recorded., Results: Cure rates were 21 of 30 (70%; 95% confidence interval [CI], 52%-83%) for IL Sb, 4 of 20 (20%; 95% CI, 8%-42%) for cryotherapy, and 5 of 30 (17%; 95% CI, 7%-34%) for placebo cream (P < .001 for IL Sb vs each other group). IL Sb adverse events were limited to injection site pain, with a mean value of 1.0 (mild)., Conclusions: The comparative cure rate, small amount of drug administered, and tolerance data for IL Sb suggest that if local therapy for single L. braziliensis lesions is chosen, this treatment is attractive. Given the difficulties of performing placebo-controlled trials in the New World, the combined placebo and cryotherapy cure rate (18%; 95% CI, 10%-31%) is likely to become the standard against which future interventions for L. braziliensis are compared., Clinical Trials Registration: NCT01300975.

Human-made and environmental changes constitute a major risk factor for the (re-)emergence and spread of leishmaniasis; surveillance of the transmission cycle is essential in this context. This study integrated entomological and molecular parasitological techniques to document the transmission pattern of a peridomestic focus of Leishmania in the Isiboro Secure area of Bolivia. First the spatial distribution and relative density of phlebotomine sand flies, genus Lutzomyia, were established. Lutzomyia shawi was the predominant species in domestic and peridomestic environments (90% from all collections). Second, direct application of the hsp70 PCR to sand fly extracts detected Leishmania infections in Lu. shawi only, and gave an estimated infection rate of 0.21 to 0.38%. The cleavage of the hsp70 amplicon with restriction enzymes (hsp70 PCR-RFLP) allowed identification of Le. (V.) braziliensis and Le. (V.) guyanensis in Lu. shawi captured in the same village. These two parasite species were also found in humans from the study region, supporting the co-existence of two transmission cycles involving the same sand fly species. This study demonstrated the use of PCR-RFLP in the identification of Leishmania in sand fly pools which could lead to the development of methods for screening large sand fly populations in Latin America.