American cutaneous leishmaniasis in French Guiana: a retrospective comparison between liposomal amphotericin B and meglumine antimoniate

[Overview of infectious and non-infectious diseases in French Guiana in 2022]

Source of many myths, French Guiana represents an exceptional territory due to the richness of its biodiversity and the variety of its communities. The only European territory in Amazonia, surrounded by the Brazilian giant and the little-known Suriname, Ariane 6 rockets are launched from Kourou while 50% of the population lives below the poverty line. This paradoxical situation is a source of health problems specific to this territory, whether they be infectious diseases with unknown germs, intoxications or chronic pathologies.Some infectious diseases such as Q fever, toxoplasmosis, cryptococcosis or HIV infection are in common with temperate countries, but present specificities leading to sometimes different management and medical reasoning. In addition to these pathologies, many tropical diseases are present in an endemic and / or epidemic mode such as malaria, leishmaniasis, Chagas disease, histoplasmosis or dengue. Besides, Amazonian dermatology is extremely varied, ranging from rare but serious pathologies (Buruli ulcer, leprosy) to others which are frequent and benign such as agouti lice (mites of the family Trombiculidae) or papillonitis. Envenomations by wild fauna are not rare, and deserve an appropriate management of the incriminated taxon. Obstetrical, cardiovascular and metabolic cosmopolitan pathologies sometimes take on a particular dimension in French Guiana that must be taken into account in the management of patients. Finally, different types of intoxication are to be known by practitioners, especially due to heavy metals.European-level resources offer diagnostic and therapeutic possibilities that do not exist in the surrounding countries and regions, thus allowing the management of diseases that are not well known elsewhere.Thanks to these same European-level resources, research in Guyana occupies a key place within the Amazon region, despite a smaller population than in the surrounding countries. Thus, certain pathologies such as histoplasmosis of the immunocompromised patient, Amazonian toxoplasmosis or Q fever are hardly described in neighboring countries, probably due to under-diagnosis linked to more limited resources. French Guiana plays a leading role in the study of these diseases.The objective of this overview is to guide health care providers coming to or practicing in French Guiana in their daily practice, but also practitioners taking care of people returning from French Guiana.

Liposomal Amphotericin B for Treatment of Leishmaniasis: From the Identification of Critical Physicochemical Attributes to the Design of Effective Topical and Oral Formulations

The liposomal amphotericin B (AmB) formulation, AmBisome^®, still represents the best therapeutic option for cutaneous and visceral leishmaniasis. However, its clinical efficacy depends on the patient's immunological status, the clinical manifestation and the endemic region. Moreover, the need for parenteral administration, its side effects and high cost significantly limit its use in developing countries. This review reports the progress achieved thus far toward the understanding of the mechanism responsible for the reduced toxicity of liposomal AmB formulations and the factors that influence their efficacy against leishmaniasis. It also presents the recent advances in the development of more effective liposomal AmB formulations, including topical and oral liposome formulations. The critical role of the AmB aggregation state and release rate in the reduction of drug toxicity and in the drug efficacy by non-invasive routes is emphasized. This paper is expected to guide future research and development of innovative liposomal formulations of AmB.

Meglumine antimoniate was associated with a higher cure rate than liposomal amphotericin B in the treatment of American tegumentary leishmaniasis: A retrospective cohort study from a Leishmania braziliensis-endemic area

Background

Pentavalent antimonials (PAs) are the primary therapeutic option for American tegumentary leishmaniasis (ATL). However, the use of these drugs is complicated by adverse events (AEs), resistance and contraindications. Alternative therapies relative effectiveness is not well established.

Objective

This study compared the effectiveness of liposomal amphotericin B (LAB) with intravenous meglumine antimoniate (NMG) in the treatment of ATL. We also analysed and compared associated AEs and treatment interruption rates.

Methods

This was a retrospective cohort study from Brazil. The potential risk factors for the primary outcome were age, sex, total cutaneous lesion area, presence of mucosal lesions, AEs and treatment interruption. The primary outcome was lesion healing within 6 months of treatment. AEs and treatment interruption were also analysed. Multiple analytic strategies were employed to evaluate the reliability of the results.

Results

Before propensity score (PS) matching, patients in the LAB group were older and had a higher frequency of mucosal lesions. The NMG group had a higher cure rate than the LAB group (cure rate 88% versus 55% respectively) in the adjusted analysis (relative risk (RR)=1.55 95% CI: 1.19 - 2.02) and after PS matching (RR=1.63 95% CI: 1.20 - 2.21). NMG group had a higher AE rate (event rate 52% versus 44%) in the adjusted analysis (RR= 1.61, 95% CI: 1.06 - 2.43, p=0.02), but this result was not observed after PS matching (RR= 0.87, 95% CI: 0.49 -1.52, p= 0.61).

Conclusions

We observed that the NMG group had a higher cure rate than the LAB group, with an equivocally higher EV rate in the adjusted analysis.

Treatment of Pediatric Cutaneous Leishmaniasis with Liposomal Amphotericin B

BACKGROUND

The use of liposomal amphotericin B (L-AmB) in the treatment of cutaneous leishmaniasis (CL) is increasing. However, few data are available regarding the efficacy and safety of L-AmB in pediatric CL patients.

AIMS

Our aim in this study is to evaluate the efficacy and safety of L-AmB in pediatric CL patients.

METHODS

Pediatric patients admitted to a tertiary training and research hospital in a hyperendemic region for CL between January 2019 and May 2021 and receiving L-AmB therapy for CL were included in this retrospective study. L-AmB treatment was administered as 3 mg/kg for 5 consecutive days and on the 10th day, in a total of 6 doses (18 mg/kg total dose).

RESULT

Fifty-two pediatric patients who received L-AmB therapy for CL were included in the study. In the follow-up 3 months after L-AmB treatment, 16 (31%) patients showed complete clinical recovery, while treatment failure was detected in 36 (69%) patients.

CONCLUSION

In conclusion, considering the low treatment success rate in our study, we think that the L-AmB dose used in our study is not an appropriate treatment option for the treatment of pediatric CL patients. However, we think that prospective studies with a large number of patients treated with higher doses of L-AmB and in whom the causative agents of CL were determined are needed. This article is protected by copyright. All rights reserved.

Formulation of Amphotericin B in PEGylated Liposomes for Improved Treatment of Cutaneous Leishmaniasis by Parenteral and Oral Routes

Liposomal amphotericin B (AmB) or AmBisome® is the most effective and safe therapeutic agent for visceral leishmaniasis (VL), but its clinical efficacy is limited in cutaneous leishmaniasis (CL) and HIV/VL co-infection. The aim of this work was to develop a formulation of AmB in PEGylated liposomes and compare its efficacy to AmBisome® in a murine model of CL. Formulations of AmB in conventional and PEGylated liposomes were characterized for particle size and morphology, drug encapsulation efficiency and aggregation state. Those were compared to AmBisome® in Leishmania amazonensis-infected BALB/c mice for their effects on the lesion size growth and parasite load. The conventional and PEGylated formulations showed vesicles with 100–130 nm diameter and low polydispersity, incorporating more than 95% of AmB under the non-aggregated form. Following parenteral administration in the murine model of CL, the PEGylated formulation of AmB significantly reduced the lesion size growth and parasite load, in comparison to control groups, in contrast to conventional liposomal AmB. The PEGylated formulation of AmB was also effective when given by oral route on a 2-day regimen. This work reports for the first time that PEGylated liposomal AmB can improve the treatment of experimental cutaneous leishmaniasis by both parenteral and oral routes.

Cutaneous leishmaniasis in travellers and migrants: a 10-year case series in a Canadian reference centre for tropical diseases

BACKGROUND

Cutaneous leishmaniasis is increasingly encountered in returned travellers and migrants to nonendemic countries. We sought to describe the clinical characteristics and treatment outcomes of cases of cutaneous leishmaniasis diagnosed at our reference centre over a 10-year period.

METHODS

This case series included all laboratory-confirmed cases of cutaneous leishmaniasis in travellers and migrants for whom complete clinical data were available, diagnosed between January 2008 and October 2018 at the J.D. MacLean Centre for Tropical Diseases in Montréal. We examined the number of cases each year. We used descriptive statistics to summarize variables (e.g., demographic characteristics, travel history, clinical presentation, diagnostic methods, treatments, adverse events) extracted from the patients' electronic medical records. The primary outcome for evaluating clinical response to treatment was defined as the complete re-epithelialization of the wound surface at 1 year.

RESULTS

We identified 48 patients who received diagnoses of cutaneous leishmaniasis in the 10-year study period, including 33 exposed in the Americas and 15 exposed in other regions (median age 43.5 [range 1-75] yr); 28 [58%] males). The annual number of cases increased from 9 in 2008/09 to 16 in 2017/18. The median time from onset to diagnosis was 89 (IQR 58-134) days. Liposomal amphotericin B was the most commonly used initial treatment (20 [53%] patients). Thirty-five patients completed their follow-up, and 11 had successful response to 1 course of liposomal amphotericin B. Adverse events (including acute kidney injury, increased pancreatic enzymes and fatigue) were reported in 6 (30%) patients. Clinical cure was achieved within 1 year for 32 (91%) of the 35 patients who completed follow-up.

INTERPRETATION

This study showed an increase in the number of cases of cutaneous leishmaniasis seen in our centre over the study period, likely because of increased travel and migration. This diagnosis should be considered in travellers and migrants with a chronic cutaneous lesion.

Outbreak of Cutaneous Leishmaniasis among military personnel in French Guiana, 2020: Clinical, phylogenetic, individual and environmental aspects

Background

Cutaneous Leishmaniasis (CL) is endemic in French Guiana but cases are usually sporadic. An outbreak signal was issued on May 15^th 2020 with 15 suspected cases after a military training course in the rainforest. An outbreak investigation was carried out.

Methodology/Principal findings

Thirty cases were confirmed. Leishmania guyanensis was the most frequent species (90%). The most frequent presentation was ulcerative (90%). Lesions on the face and hands were frequent (40% each). Eight cases (26%) presented a poor outcome after treatment with pentamidine and required a second line with amphotericin B. Three of them required further treatments with meglumine antimoniate or miltefosine. Two spots within the training area were deemed as likely sites of contamination, due to illegal logging. The isolated Leishmania strains did not form a separate cluster. Participation in Week 13 of year 2020 was associated with infection (OR = 4.59 [1.10–19.83]; p = 0.016) while undergoing only the “Fighting” exercise was protective (OR = 0.1 [0–0.74]; p = 0.021). There was no association between infection and other risk factors at the individual level. The attack rate of Regiment B (14/105 = 13.3%) was significantly higher (OR = 4.22 [1.84–9.53], p = 0.0001) compared to Regiment A (16/507 = 3.2%). The attack rate during this training course (30/858 = 3.5%) was significantly higher (OR 2.29 [1.28–4.13]; p = 0.002) than for other missions in French Guiana during the same period (22/1427 = 1.5%).

Conclusions

This outbreak could be explained by a combination of factors: climatic conditions around week 13, at-risk activities including night trainings, absence of impregnation, a lesser experience of rainforest duties in Regiment B and illegal logging attracting sandflies on military training grounds.

Cutaneous Leishmaniasis is caused by parasites of the Leishmania genus and infects humans after a sandfly bite. Outbreaks are rare and hard to investigate in isolated tropical areas. In this study, the authors explored the different possible origins of an outbreak of cutaneous leishmaniasis among soldiers training in the rainforest of French Guiana. The outbreak occurred in March 2020. Concerning the symptoms, several patients presented resistant infections and multiple lines of treatment, raising the issue of resistant Leishmania strains. The different strains isolated during the outbreak were not genetically closed, as far as routine PCR techniques would indicate. The authors looked for individual behaviours exposing soldiers to sandfly bites but none was significantly associated with infection. The authors found two spots in the military training areas where illegal logging probably increased the density of sandflies and put service members at risk. The 13^th week of 2020 was associated to a higher risk of infection due to climatic conditions. This study shows how interactions between humans and the rainforest can increase the risk of parasitic outbreaks.

Treatment of Complex Cutaneous Leishmaniasis with Liposomal Amphotericin B

BACKGROUND

There is no consensus for the best treatment of complex cutaneous leishmaniasis (CL). We aimed to describe a cohort of CL, focusing on liposomal amphotericin B (L-AmB) treatment outcome.

METHODS

We performed a retrospective study in Vall d'Hebron University Hospital (Barcelona, Spain). All patients with parasitologically proven CL diagnosed from 2012 to 2018 were included.

RESULTS

The analysis included 41 patients with CL. The median age was 39 years (IQR 12- 66); 12 (29%) were children, and 29 (71%) were men. Regarding treatment, 24 (59%) received local treatment, whereas 17 (41%) had complex CL and were offered intravenous systemic treatment. Sixteen patients received L-AmB; eight (50%) had adverse events, and three (19%) discontinued treatment for safety reasons. All cases were considered cured within the first year post-treatment.

CONCLUSIONS

L-AmB for complex CL showed no treatment failures, offering an alternative treatment option for patients with complex CL. Clinicians should pay close attention to the potential adverse events of L-AmB and adopt an active drug safety surveillance scheme to rapidly detect reversible side effects.

Intravenous liposomal amphotericin B efficacy and safety for cutaneous and mucosal leishmaniasis: a systematic review and meta-analysis protocol

INTRODUCTION

Treatment of cutaneous and mucosal leishmaniasis (CL and ML, respectively) must be individualised as there is no universal therapeutic approach. Intravenous liposomal amphotericin B (L-AmB) is an accessible and relatively safe treatment that has been increasingly used for the treatment of CL and ML. While several descriptive studies have been published on the efficacy and safety of L-AmB, there are no interventional studies. Moreover, the findings from published studies have not yet been integrated and synthesised. Therefore, we aim to evaluate and consolidate the descriptive evidence on the efficacy and the safety of Intravenous L-AmB treatment for CL and ML in both the New and Old World.

METHODS AND ANALYSES

A systematic review of all relevant study types with no restriction on date or language of publication will be conducted. Online databases including MEDLINE, The Cochrane Library, EMBASE, EBSCO, Scopus, Ovid and WHO databases were searched on 3 April 2020. The search included all study types that assess Intravenous L-AmB treatment for CL and ML in humans. The Population, Intervention, Comparison, Outcome and Study Design strategy and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines will be used to determine which studies will be selected for final inclusion. The quality of included case series and case reports will be assessed using modified quality assessment tools. A narrative synthesis of the findings will be provided and the primary outcome and secondary outcome of interest, response rate and adverse events rate, respectively, and the 95% CI will be ascertained. Estimates from individual studies will be pooled using random-effects model.

ETHICS AND DISSEMINATION

This systematic review does not require formal ethical approval since no primary data will be collected. Findings will be disseminated through a peer-reviewed publication and relevant conferences.

PROSPERO REGISTRATION NUMBER

CRD42020173440.

Validation of Swab Sampling and SYBR Green-Based Real-Time PCR for the Diagnosis of Cutaneous Leishmaniasis in French Guiana

Recent studies have highlighted the interest in noninvasive sampling procedures coupled with real-time PCR methods for the detection of Leishmania species in South America. In French Guiana, the sampling method still relied on skin biopsies. Noninvasive protocols should be tested on a large annual cohort to improve routine laboratory diagnosis of cutaneous leishmaniasis. Therefore, we evaluated the performance of a new Leishmania detection and species identification protocol involving cotton swabs and SYBR green-based real-time PCR of the Hsp70 gene, coupled with Sanger sequencing. Between May 2017 and May 2018, 145 patients with ulcerated lesions compatible with cutaneous leishmaniasis were included in the study at the Cayenne Hospital and its remote health centers. Each patient underwent scrapings for a smear, skin biopsies for parasite culture and PCR-restriction fragment length polymorphism (RFLP) (RNA polymerase II), and sampling with a cotton swab for SYBR green-based PCR. The most accurate diagnostic test was the SYBR green-based PCR on swab samples, showing 98% sensitivity. The mean PCR cycle threshold (C_T ) was 24.4 (minimum C_T , 17; maximum C_T , 36) and was <35 in 97.6% of samples. All samples positive by SYBR green-based real-time PCR were successfully identified at the species level by DNA sequencing. This new method should be considered for routine diagnosis of cutaneous leishmaniasis in South America and especially for remote areas, since noninvasive collection tools are easier to use and require fewer precautions for transportation.