Clinical and demographic stratification of test performance: a pooled analysis of five laboratory diagnostic methods for American cutaneous leishmaniasis

ELISA with recombinant antigen Lb6H validated for the diagnosis of American tegumentary leishmaniasis

American tegumentary leishmaniasis (ATL) diagnosis is an open question, and the search for a solution is urgent. The available tests that detect the etiological agent of the infection are specific for ATL diagnosis. However, they present disadvantages, such as low sensitivity and the need for invasive procedures to obtain the samples. Immunological methods (leishmanin skin test and search for anti-Leishmania antibodies) are good alternatives to the etiological diagnosis of ATL. Presently, we face problems with disease confirmation due to the discontinuity in the production of leishmanin skin test antigen, particularly in resource-poor settings. Aiming to diagnose ATL, we validated rLb6H-ELISA for IgG antibodies using 1,091 samples from leishmaniasis patients and healthy controls, divided into four panels, living in 19 Brazilian endemic and non-endemic states. The rLb6H-ELISA showed a sensitivity of 98.6% and a specificity of 100.0%, with the reference panel comprising 70 ATL patient samples and 70 healthy controls. The reproducibility evaluation showed a coefficient of variation of positive samples ≤ 8.20% for repeatability, ≤ 17,97% for reproducibility, and ≤ 8.12% for homogeneity. The plates sensitized with rLb6H were stable at 4°C and -20°C for 180 days and 37°C for seven days, indicating 12 months of validity. In samples of ATL patients from five research and healthcare centers in endemic and non-endemic areas, rLb6H-ELISA showed a sensitivity of 84.0%; no significant statistical difference was observed among the five centers (chi-square test, p = 0.13). In samples of healthy controls from four areas with different endemicity, a specificity of 92.4% was obtained; lower specificity was obtained in a visceral leishmaniasis high endemicity locality (chi-square test, p<0.001). Cross-reactivity was assessed in 166 other disease samples with a positivity of 13.9%. Based on the good diagnostic performance and the reproducibility and stability of the antigen, we suggest using ELISA-rLb6H to diagnose ATL.

In Situ versus Systemic Immune Response in the Pathogenesis of Cutaneous Leishmaniasis

The role of the immune response in the pathogenesis of cutaneous leishmaniasis (CL) due to Leishmania (Viannia) braziliensis is predominantly carried out via blood cells. Here, we evaluate whether cytokine production by peripheral blood mononuclear cells (PBMCs) reflects what has been documented at the lesion site. The participants included 22 CL patients diagnosed with a positive PCR. PBMCs were stimulated for 72 h with a soluble leishmania antigen (SLA). Biopsies obtained from the edge of the ulcers were incubated for the same period. Cytokines in supernatants were assessed via ELISA. TNF, IL-1β, IL-6, IL-17, and granzyme B (GzmB) were higher in the supernatants of biopsies than in PBMCs, but IFN-γ was higher in the supernatants of PBMCs than in biopsies. There was a positive correlation between IFN-γ and TNF in PBMCs, and an inverse correlation between TNF and IL-10 in the cells from the lesion site. A strong correlation between IL-1β, IL-17, and GzmB was observed in the biopsies, and a positive correlation was detected between these cytokines and the lesion size. Our results indicate that the immune response in L. braziliensis lesions is different from that observed in peripheral blood, and our data suggest that in addition to IL-1β and GzmB, IL-17 participates in the pathology of CL.

Treatment of cutaneous leishmaniasis with a sequential scheme of pentamidine and tamoxifen in an area with a predominance of Leishmania (Viannia) guyanensis: A randomised, non-inferiority clinical trial

OBJECTIVE

To determine whether a combination of a single intramuscular (IM) dose of pentamidine (7 mg/kg) followed by oral tamoxifen 40 mg/day for 20 days is non-inferior to three IM doses of pentamidine 7 mg/kg in the treatment of cutaneous leishmaniasis with a margin of 15%.

METHODS

Phase II, randomised, controlled, open-label, non-inferiority clinical trial. Primary outcome was the complete healing of the lesions 6 months after starting treatment. Secondary outcomes were healing 3 months after starting treatment and determining the presence and severity of adverse effects (AE).

RESULTS

The research was concluded with 49 patients; Leishmania (Viannia) guyanensis was the most frequent species isolated. In the primary outcome, 18 (72%) (95% CI: 52.4%-85.7%) of the 25 patients allocated to the intervention group and 24 (100%) (95% CI: 86.2%-100%) of the control group (p = 0.015) met the established criteria of cure. There was no AE with tamoxifen.

CONCLUSION

Although a 72% cure rate presented by the combination of tamoxifen and pentamidine was lower than in the control group that achieved a 100% cure, it is still a safe and is a clinically relevant result. It indicates that the therapeutic scheme evaluated may be a promising option for populations in remote areas, however it should be further studied, in order to include a larger number of patients.

Touching Base with Some Mediterranean Diseases of Interest from Paradigmatic Cases at the "Magna Graecia" University Unit of Infectious Diseases: A Didascalic Review

Among infectious diseases, zoonoses are increasing in importance worldwide, especially in the Mediterranean region. We report herein some clinical cases from a third-level hospital in Calabria region (Southern Italy) and provide a narrative review of the most relevant features of these diseases from epidemiological and clinical perspectives. Further, the pathogenic mechanisms involved in zoonotic diseases are reviewed, focusing on the mechanisms used by pathogens to elude the immune system of the host. These topics are of particular concern for individuals with primary or acquired immunodeficiency (e.g., people living with HIV, transplant recipients, patients taking immunosuppressive drugs). From the present review, it appears that diagnostic innovations and the availability of more accurate methods, together with better monitoring of the incidence and prevalence of these infections, are urgently needed to improve interventions for better preparedness and response.

Mapping linear B-cell epitopes of the Tryparedoxin Peroxidase and its implications in the serological diagnosis of tegumentary leishmaniasis

Diagnosis of tegumentary leishmaniasis (TL) is essential to avoid permanent damage and severe functional sequelae and there is an urgent need to discover new antigens. The present study aimed to comprehensively evaluate the potential use of the Tryparedoxin Peroxidase (TryP) as an antigen for serological tests. The proposal integrates data from immunoproteomics with immunoinformatics, in addition to a precise analysis of protein levels in the evolutionary stages of the parasite by flow cytometry. To evaluate the performance in the diagnosis of TL, Enzyme-Linked Immunosorbent Assay (ELISA) assays were performed using the recombinant protein and the respective B-cell epitope, followed by an analysis of the contribution of this peptide in the recognition of the protein by patients, evaluated by serum depletion assays. We showed that the TryP has a linear B-cell epitope with high divergence compared to orthologs from Trypanosoma cruzi and Homo sapiens. The results also show high expression and positive cells for TryP (TryP⁺) in the infective metacyclic promastigotes (MET) and intracellular (24 and 48 hours) stages. From the depletion assays, it was possible to confirm the contribution of the peptide in the specific recognition of the TryP protein by patients with TL (13.7-15.9%). ELISA using the peptide showed high performance in the diagnosis compared to the recombinant TryP (rTryP), Soluble Leishmania braziliensis Antigen (sLba) and Immunofluorescence Assay (IFA) with accuracy of 94.29, 89.29, 65.00 and 37.14%, respectively). We can conclude that the MNEPAPP peptide is a potential antigen for the diagnosis of TL.

Validation of an In-House ELISA Method in the Diagnosis of Cutaneous Leishmaniasis Caused by Leishmania donovani in Hambantota District, Sri Lanka

Clinical diagnosis has become a challenge amidst a surge of cutaneous leishmaniasis in Southern Sri Lanka. The routine diagnostic method, slit-skin smear (SSS), has variable sensitivity, leading to undiagnosed cases. Improved diagnostics are urgently needed. We assessed a new in-house ELISA method for its diagnostic capabilities against ITS-1 nested PCR (gold standard—Gs). A cohort of 190 clinical CL cases was examined by SSS microscopy, anti-rKRP42 IgG ELISA (serum- and urine-based), and rK39-Immunochromatographic strip test. Validation was done using non-endemic sera, and cutoffs were developed using the receiver operating curve. The sensitivity of SSS for case detection was 77.9% (authors) and 76.3% (technicians). ELISA vs. Gs demonstrated sensitivity (Sn) = 94.4%; specificity (Sp) = 50.0%; positive predictive value (PPV) = 97.1%; negative predictive value (NPV) = 33.3%; Kappa agreement (Kp) = 0.39/p < 0.01. Comparison of the combination method (SSS by technicians and ELISA) vs. Gs showed: Sn = 98.9%; Sp = 30.0; PPV = 96.2; NPV 60.0%; Kp = 0.378/p < 0.01. All methods performed better compared to SSS (29.4%) where the clinical diagnosis was doubtful (PCR = 94.15%; serum ELISA = 88.2%; combination = 94.1%; p < 0.01 for all). High serum anti-rKRP42 titers were seen in those with multiple lesions. Anti-rKRP42 urine ELISA was suboptimal as a diagnostic test. A 9% rate of positivity was seen for rk39-ICT, and positives recorded high anti-rKRP42 titers. The diagnostic accuracy can be increased above the level of the Gs by combining SSS and ELISA. Advanced studies are required to understand the association between rk39-ICT positivity and high anti-rKRP42 titers.

Culture of Cutaneous Leishmania from Skin Biopsy Specimens

This protocol describes the culture of Leishmania parasites from skin biopsy samples of patients with cutaneous lesions. The use of antibiotics to prevent bacterial contamination of these cultures increases the ability of researchers to collect isolates for various research purposes, including genetic analysis and in vitro and in vivo experiments. © Published 2022. This article is a U.S. Government work and is in the public domain in the USA. Basic Protocol: Culture of Leishmania from skin biopsy specimens.

Evaluation of the CL Detect Rapid Test in Ethiopian patients suspected for Cutaneous Leishmaniasis

Background

Cutaneous leishmaniasis (CL) is common in Ethiopia, mainly affecting impoverished populations in rural areas with poor access to health care. CL is routinely diagnosed using skin slit smear microscopy, which requires skilled staff and appropriately equipped laboratories. We evaluated the CL Detect Rapid Test (InBios, Washington, USA), which is supplied with a dental broach sampling device, as a diagnostic alternative which could be used in field settings.

Methodology/Principal findings

We evaluated the diagnostic accuracy of the CL Detect Rapid Test on skin slit and dental broach samples from suspected CL patients at the Leishmaniasis Research and Treatment Center in Gondar, Ethiopia. A combined reference test of microscopy and PCR on the skin slit sample was used, which was considered positive if one of the two tests was positive. We recruited 165 patients consecutively, of which 128 (77.6%) were confirmed as CL. All microscopy-positive results (n = 71) were also PCR-positive, and 57 patients were only positive for PCR. Sensitivity of the CL Detect Rapid Test on the skin slit was 31.3% (95% confidence interval (CI) 23.9–39.7), which was significantly higher (p = 0.010) than for the dental broach (22.7%, 95% CI 16.3–30.6). Sensitivity for both methods was significantly lower than for the routinely used microscopy, which had a sensitivity of 55.5% (IQR 46.8–63.8) compared to PCR as a reference.

Conclusions/Significance

The diagnostic accuracy of the CL Detect Rapid Test was low for skin slit and dental broach samples. Therefore, we do not recommend its use neither in hospital nor field settings.

Trial registration

This study is registered at ClinicalTrials.gov as NCT03837431.

Cutaneous leishmaniasis (CL) is common in Ethiopia, and mainly affects rural areas with poor access to health care. CL is routinely diagnosed using microscopy on a skin slit sample, which requires skilled staff and appropriately equipped laboratories. We evaluated the diagnostic accuracy of the CL Detect Rapid Test as an alternative which could be used in field settings. In a population of 165 patients suspected to have CL, 78% was confirmed to have CL by PCR. We found that the CL Detect Rapid Test on the supplied dental broach had a sensitivity of only 23%; on a skin slit sample, the Rapid Test had a slightly higher sensitivity with 31%. The routine diagnostic test of microscopy on the skin slit had a significantly higher sensitivity with 56%. These findings show that the sensitivity of the CL Detect Rapid Test is low, and is much worse than that of the currently used diagnostic method. Therefore, we do not recommend it to be used for diagnosing CL in Ethiopia.

Leishmania RNA virus-1 is similarly detected among metastatic and non-metastatic phenotypes in a prospective cohort of American Tegumentary Leishmaniasis

American Tegumentary Leishmaniasis (ATL) is an endemic and neglected disease of South America. Here, mucosal leishmaniasis (ML) disproportionately affects up to 20% of subjects with current or previous localised cutaneous leishmaniasis (LCL). Preclinical and clinical reports have implicated the Leishmania RNA virus-1 (LRV1) as a possible determinant of progression to ML and other severe manifestations such as extensive cutaneous and mucosal disease and treatment failure and relapse. However, these associations were not consistently found in other observational studies and are exclusively based on cross-sectional designs. In the present study, 56 subjects with confirmed ATL were assessed and followed out for 24-months post-treatment. Lesion biopsy specimens were processed for molecular detection and quantification of Leishmania parasites, species identification, and LRV1 detection. Among individuals presenting LRV1 positive lesions, 40% harboured metastatic phenotypes; comparatively 58.1% of patients with LRV1 negative lesions harboured metastatic phenotypes (p = 0.299). We found treatment failure (p = 0.575) and frequency of severe metastatic phenotypes (p = 0.667) to be similarly independent of the LRV1. Parasite loads did not differ according to the LRV1 status (p = 0.330), nor did Leishmanin skin induration size (p = 0.907) or histopathologic patterns (p = 0.780). This study did not find clinical, parasitological, or immunological evidence supporting the hypothesis that LRV1 is a significant determinant of the pathobiology of ATL.

The Leishmania RNA virus-1 (LRV1) has been implicated as a possible modulator agent in the pathogenesis of leishmaniasis. In-vivo and in-vitro studies have depicted specific mechanisms of how LRV1 could lead to metastasis. Clinical studies and epidemiological evidence have both supported and rejected the hypothesis that LRV1 is a relevant determinant of progression, treatment failure and clinical severity of American Tegumentary Leishmaniasis (ATL). This lack of consistency between preclinical and clinical reports requires further longitudinal studies to clarify the role of LRV1 in ATL. Due to the complex nature of ATL, as other frequent human diseases, these studies should tackle multiple determinants of pathogenicity, including LRV1 status, parasite features, immune status, and prevalent comorbidities affecting individuals in endemic settings. Also, critical methodological aspects allowing for the reliable identification and quantification of LRV1 should be guaranteed.

Membrane Technology for Rapid Point-of-Care Diagnostics for Parasitic Neglected Tropical Diseases

Parasitic neglected tropical diseases (NTDs) affect over one billion people worldwide, with individuals from communities in low-socioeconomic areas being most at risk and suffering the most. Disease management programs are hindered by the lack of infrastructure and resources for clinical sample collection, storage, and transport and a dearth of sensitive diagnostic methods that are inexpensive as well as accurate. Many diagnostic tests and tools have been developed for the parasitic NTDs, but the collection and storage of clinical samples for molecular and immunological diagnosis can be expensive due to storage, transport, and reagent costs, making these procedures untenable in most areas of endemicity. The application of membrane technology, which involves the use of specific membranes for either sample collection and storage or diagnostic procedures, can streamline this process, allowing for long-term sample storage at room temperature. Membrane technology can be used in serology-based diagnostic assays and for nucleic acid purification prior to molecular analysis. This facilitates the development of relatively simple and rapid procedures, although some of these methods, mainly due to costs, lack accessibility in low-socioeconomic regions of endemicity. New immunological procedures and nucleic acid storage, purification, and diagnostics protocols that are simple, rapid, accurate, and cost-effective must be developed as countries progress control efforts toward the elimination of the parasitic NTDs.

Diagnostic Efficacy of Recombinase-Polymerase-Amplification Coupled with Lateral Flow Strip Reading in Patients with Cutaneous Leishmaniasis from the Amazonas Rainforest of Perú

Cutaneous leishmaniasis (CL) is highly prevalent in rural and sylvatic regions of Latin America, with an estimated 55,000 annual cases. Diagnosis in resource-limited areas still relies on microscopy of dermal scrapings, while more sensitive methods like PCR are not attainable due to costs and lack of adequate health infrastructure. Isothermal amplification of Leishmania DNA can be performed without sophisticated equipment and training and may become a point of care (POC) test for health care centers with scarce resources. We evaluated the efficacy of recombinase-polymerase-amplification (RPA-LF) to diagnose CL in 226 patients attending a clinic in Puerto Maldonado within the Peruvian Amazon basin. Conventional PCR targeting kinetoplast DNA (kDNA-PCR) was used as the gold standard. Eight of 226 patients were considered true negatives (microscopy, kDNA-PCR, and RPA-LF negative), while RPA-LF resulted positive in 186 of 204 kDNA-PCR positive patients, yielding 91.2% (confidence interval [CI] = 86.5-94.4%) sensitivity and 93% (CI 88.6-95.8%) positive predictive value. There were 14% (32/226) discrepant samples alternating positive and negative results in similar proportions between both tests. Quantitative PCR used to resolve the discrepancies suggested that they occurred in samples with scarce parasite numbers as determined by high cycle threshold (Ct) values (≥32; cutoff 35.5). Microscopy had the lowest sensitivity of all methods (45.4%). Nested real-time PCR performed in 71 samples determined that Leishmania (Viannia) braziliensis was highly prevalent (69/71), and Leishmania (Viannia) lainsoni was present in only two isolates. Results indicated that RPA-LF has POC potential for CL endemic areas, yet further simplification and optimization coupled with field validation will be necessary to confirm its broad applicability.

Development of a chimeric protein based on a proteomic approach for the serological diagnosis of human tegumentary leishmaniasis

Leishmania braziliensis is responsible for most cases of human tegumentary leishmaniasis (HTL) and has caused a wide range of clinical manifestations, including cutaneous (CL) and mucosal leishmaniasis (ML). The diagnosis is based on criteria that consider epidemiological data, clinical findings, and laboratory tests and is hard to establish. For laboratory tests, none of the assays available can be considered gold standards for disease detection. In addition, the Montenegro skin test, essential to supporting infectologists in the clinical management of the disease, is no longer available in Brazil. Thus, the aim of this study was to develop new targets to be used in diagnostic tests for HTL. In the first step, we carried out two-dimensional gel electrophoresis, followed by mass spectrometry, combined with heat map analysis and immunoproteomics approach, and disclosed eight proteins expressed in the amastigote stage specifically recognized by serum from CL and ML patients. A chimeric protein was designed based on the combination of thirteen linear B-cell epitopes, identified by immunoinformatics analysis, from L. braziliensis proteins. Our results showed that the strategy used in this work was successful in developing an antigen to be used in immunological assays (100.0% sensitivity and specificity) in the detection of HTL cases and in comparison with results obtained from an ELISA using soluble L. braziliensis antigen (SLb-Antigen) and immunofluorescence assay (Bio-Manguinhos/FIOCRUZ). The present technology opens the door for its use in field exams by means of an immunochromatographic test, which will be even more helpful in regions without laboratory structures.Key points• Rational strategy to develop antigens.• Integration between immunoproteomic and immunoinformatics analysis.• Chimeric protein shows high performance in HTL diagnosis.

Comparison of Whole Genome Sequencing versus Standard Molecular Diagnostics for Species Identification in the Leishmania Viannia Subgenus

The prognosis and treatment of New World tegumentary leishmaniasis is dependent on the infecting species, yet such species identification in the Leishmania Viannia subgenus poses a diagnostic challenge. Currently, speciation relies on standard molecular techniques such as restriction fragment length polymorphism (RFLP) analysis, and Sanger sequencing (SS). Whole-genome sequencing (WGS) is a robust and increasingly cost-efficient tool that may improve Leishmania species identification. We evaluated WGS versus standard RFLP-SS for species identification in three reference and five clinical strains of Leishmania Viannia spp. Internal transcribed spacer1 (its1), cysteine proteinase b (cpb), and heat shock protein 70 (hsp70) polymerase chain reaction-restriction fragment length polymorphism (RFLP) was performed, followed by SS of the its2, cpb, hsp70, and mannose phosphate isomerase (mpi) loci. After de novo assembly, sequences were mapped, and homology compared with both reference strains and reference genomes on National Center for Biotechnology Information. All American Type Culture Collection strains were confirmed to be single-species of L. V. braziliensis, L. V. guyanensis, or L. V. panamensis by WGS. Conversely, RFLP-SS was able to definitively identify one of three isolates to the species level. Clinical samples were identified as either single-species (N = 3), mixed (N = 1), or hybrid (N = 1) infections by WGS, while standard molecular diagnosis required multi-target composite analysis for identification due to loci-dependent results by RFLP-SS. We have corroborated the utility of WGS as a diagnostic tool to speciate members of the L. Viannia subgenus and to discriminate between mixed and hybrid infections. WGS is a potentially useful complement to multistaged RFLP-SS for species identification in Leishmania infections.

Diagnostic performance of a Recombinant Polymerase Amplification Test-Lateral Flow (RPA-LF) for cutaneous leishmaniasis in an endemic setting of Colombia

Background

Control of cutaneous leishmaniasis by public health systems in the Americas relies on case identification and treatment. Point-of-care diagnostics that can be performed by health workers within or near affected communities could effectively bring the health system to the resource-limited sites providing early diagnosis and treatment, reducing morbidity and the burden of disease.

Methodology/principal findings

A cross-sectional study was undertaken to evaluate the diagnostic test performance of Isothermal Recombinase Polymerase Amplification (RPA) targeting Leishmania kinetoplast DNA, coupled with a lateral flow (LF) immunochromatographic strip, in a field setting and a laboratory reference center. Minimally invasive swab and FTA filter paper samples were obtained by community health workers and highly trained technicians from ulcerated lesions of > 2 weeks’ evolution from 118 patients’ ≥ 2 years of age in the municipality of Tumaco, Nariño. Extracted DNA was processed by RPA-LF at a reference center or in a primary health facility in the field. Evaluation was based on a composite “gold standard” that included microscopy, culture, biopsy and real-time polymerase chain reaction detection of Leishmania 18S rDNA. Standard of care routine diagnostic tests were explored as comparators.

Sensitivity and specificity of RPA-LF in the reference lab scenario were 87% (95%CI 74–94) and 86% (95%CI 74–97), respectively. In the field scenario, the sensitivity was 75% (95%CI 65–84) and specificity 89% (95%CI 78–99). Positive likelihood ratios in both scenarios were higher than 6 while negative likelihood ratios ranged to 0.2–0.3 supporting the usefulness of RPA-LF to rule-in and potentially to rule-out infection.

Conclusions/significance

The low complexity requirements of RPA-LF combined with non-invasive sampling support the feasibility of its utilization by community health workers with the goal of strengthening the diagnostic capacity for cutaneous leishmaniasis in Colombia.

Trial registration

ClinicalTrials.gov NCT04500873.

Limited access to diagnosis is a critical determinant of the “neglect” that defines the so-called Neglected Tropical Diseases (NTDs) including cutaneous leishmaniasis. Diagnostic tests that can be performed close to and involve the participation of the affected communities would improve access to treatment as well as diagnosis. Using non-invasive swab and filter paper samples obtained by Community Health Workers, we evaluated the diagnostic performance of an innovative and technically simple molecular test: Isothermal Recombinase Polymerase Amplification (RPA) to detect Leishmania DNA, coupled with a lateral flow (LF) strip to read the results with the naked eye. The RPA-LF test demonstrated high sensitivity and specificity and capacity to rule in or rule out a diagnosis of cutaneous leishmaniasis in both an endemic field setting and reference laboratory. The findings encourage the further optimization of the test format for Point-of-Care diagnosis by health personnel and rural health workers in endemic settings.

Bedside Diagnostics for Infections: A Guide for Dermatologists

In dermatology, there are many bedside diagnostic tests that may aid in more rapid diagnosis and early initiation of appropriate therapy. When performed correctly, these bedside diagnostic tests can provide both sensitive and specific results. We discuss bedside diagnostic tests, such as the Tzanck smear, potassium hydroxide (KOH) preparation, and mineral oil preparation, with a specific focus on their use in diagnosing infectious dermatoses.

Interventions for American cutaneous and mucocutaneous leishmaniasis

BACKGROUND

On the American continent, cutaneous and mucocutaneous leishmaniasis (CL and MCL) are diseases associated with infection by several species of Leishmania parasites. Pentavalent antimonials remain the first-choice treatment. There are alternative interventions, but reviewing their effectiveness and safety is important as availability is limited. This is an update of a Cochrane Review first published in 2009.

OBJECTIVES

To assess the effects of interventions for all immuno-competent people who have American cutaneous and mucocutaneous leishmaniasis (ACML).

SEARCH METHODS

We updated our database searches of the Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase, LILACS and CINAHL to August 2019. We searched five trials registers.

SELECTION CRITERIA

Randomised controlled trials (RCTs) assessing either single or combination treatments for ACML in immuno-competent people, diagnosed by clinical presentation and Leishmania infection confirmed by smear, culture, histology, or polymerase chain reaction on a biopsy specimen. The comparators were either no treatment, placebo only, or another active compound.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Our key outcomes were the percentage of participants 'cured' at least three months after the end of treatment, adverse effects, and recurrence. We used GRADE to assess evidence certainty for each outcome.

MAIN RESULTS

We included 75 studies (37 were new), totalling 6533 randomised participants with ATL. The studies were mainly conducted in Central and South America at regional hospitals, local healthcare clinics, and research centres. More male participants were included (mean age: roughly 28.9 years (SD: 7.0)). The most common confirmed species were L. braziliensis, L. panamensis, and L. mexicana. The most assessed interventions and comparators were non-antimonial systemics (particularly oral miltefosine) and antimonials (particularly meglumine antimoniate (MA), which was also a common intervention), respectively. Three studies included moderate-to-severe cases of mucosal leishmaniasis but none included cases with diffuse cutaneous or disseminated CL, considered the severe cutaneous form. Lesions were mainly ulcerative and located in the extremities and limbs. The follow-up (FU) period ranged from 28 days to 7 years. All studies had high or unclear risk of bias in at least one domain (especially performance bias). None of the studies reported the degree of functional or aesthetic impairment, scarring, or quality of life. Compared to placebo, at one-year FU, intramuscular (IM) MA given for 20 days to treat L. braziliensis and L. panamensis infections in ACML may increase the likelihood of complete cure (risk ratio (RR) 4.23, 95% confidence interval (CI) 0.84 to 21.38; 2 RCTs, 157 participants; moderate-certainty evidence), but may also make little to no difference, since the 95% CI includes the possibility of both increased and reduced healing (cure rates), and IMMA probably increases severe adverse effects such as myalgias and arthralgias (RR 1.51, 95% CI 1.17 to 1.96; 1 RCT, 134 participants; moderate-certainty evidence). IMMA may make little to no difference to the recurrence risk, but the 95% CI includes the possibility of both increased and reduced risk (RR 1.79, 95% CI 0.17 to 19.26; 1 RCT, 127 participants; low-certainty evidence). Compared to placebo, at six-month FU, oral miltefosine given for 28 days to treat L. mexicana, L. panamensis and L. braziliensis infections in American cutaneous leishmaniasis (ACL) probably improves the likelihood of complete cure (RR 2.25, 95% CI 1.42 to 3.38), and probably increases nausea rates (RR 3.96, 95% CI 1.49 to 10.48) and vomiting (RR 6.92, 95% CI 2.68 to 17.86) (moderate-certainty evidence). Oral miltefosine may make little to no difference to the recurrence risk (RR 2.97, 95% CI 0.37 to 23.89; low-certainty evidence), but the 95% CI includes the possibility of both increased and reduced risk (all based on 1 RCT, 133 participants). Compared to IMMA, at 6 to 12 months FU, oral miltefosine given for 28 days to treat L. braziliensis, L. panamensis, L. guyanensis and L. amazonensis infections in ACML may make little to no difference to the likelihood of complete cure (RR 1.05, 95% CI 0.90 to 1.23; 7 RCTs, 676 participants; low-certainty evidence). Based on moderate-certainty evidence (3 RCTs, 464 participants), miltefosine probably increases nausea rates (RR 2.45, 95% CI 1.72 to 3.49) and vomiting (RR 4.76, 95% CI 1.82 to 12.46) compared to IMMA. Recurrence risk was not reported. For the rest of the key comparisons, recurrence risk was not reported, and risk of adverse events could not be estimated. Compared to IMMA, at 6 to 12 months FU, oral azithromycin given for 20 to 28 days to treat L. braziliensis infections in ACML probably reduces the likelihood of complete cure (RR 0.51, 95% CI 0.34 to 0.76; 2 RCTs, 93 participants; moderate-certainty evidence). Compared to intravenous MA (IVMA) and placebo, at 12 month FU, adding topical imiquimod to IVMA, given for 20 days to treat L. braziliensis, L. guyanensis and L. peruviana infections in ACL probably makes little to no difference to the likelihood of complete cure (RR 1.30, 95% CI 0.95 to 1.80; 1 RCT, 80 participants; moderate-certainty evidence). Compared to MA, at 6 months FU, one session of local thermotherapy to treat L. panamensis and L. braziliensis infections in ACL reduces the likelihood of complete cure (RR 0.80, 95% CI 0.68 to 0.95; 1 RCT, 292 participants; high-certainty evidence). Compared to IMMA and placebo, at 26 weeks FU, adding oral pentoxifylline to IMMA to treat CL (species not stated) probably makes little to no difference to the likelihood of complete cure (RR 0.86, 95% CI 0.63 to 1.18; 1 RCT, 70 participants; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

Evidence certainty was mostly moderate or low, due to methodological shortcomings, which precluded conclusive results. Overall, both IMMA and oral miltefosine probably result in an increase in cure rates, and nausea and vomiting are probably more common with miltefosine than with IMMA. Future trials should investigate interventions for mucosal leishmaniasis and evaluate recurrence rates of cutaneous leishmaniasis and its progression to mucosal disease.

A prospective cohort study of Cutaneous Leishmaniasis due to Leishmania major: Dynamics of the Leishmanin skin test and its predictive value for protection against infection and disease

BACKGROUND

Leishmanin Skin Test (LST) is considered as a useful indicator of past infection by Leishmania parasites. However, the temporal dynamics of a positive LST under different epidemiologic scenarios and whether it relates to the protection against the recurrence of an overt disease are not fully documented.

METHODOLOGY/PRINCIPAL FINDINGS

We report here on a population based prospective study conducted on 2686 individuals living in two foci located in Central Tunisia, to assess over a one-year epidemiologic season, the incidence of Leishmania (L.) major infection and disease and changes in LST reactivity. The two foci were both endemic for Cutaneous Leishmaniasis (CL) due to L. major, but contrasted in their history for this disease (ie: an old focus versus a recent focus). We found that most infections occurred in the new focus (290/1000; 95% CI: 265-315 person-years) with an incidence rate of CL lesions 2.4 times higher than in the old focus. Likewise, the rates of LST reactivity reversion and loss, in the new focus, were 99/1000[38-116] person-years and 14/1000[8-21] person-years, respectively. Loss of LST reactivity was not noticed in the old focus. Interestingly, the incidence rates of symptomatic infection did not differ significantly according to the LST status at enrolment (negative versus positive) between the combined foci and the new one.

CONCLUSIONS/SIGNIFICANCE

Our findings confirm LST as a good tool for assessing L. major cryptic infection. However, the instability of the LST positivity in new foci should be considered as an important confounder of the outcome of this infection when developing a research protocol for vaccine trial.

HRM-PCR is an accurate and sensitive technique for the diagnosis of cutaneous leishmaniasis as compared with conventional PCR

BACKGROUND

Cutaneous leishmaniasis (CL) is considered one of the main health problems in Iran. Therefore, it is required for control and therapeutic purposes, an accurate and fast tool for the diagnosis and identification of Leishmania species.

METHODS

In the present study, three techniques, including microscopic examination, conventional PCR, and high-resolution melting (HRM)-PCR, have been evaluated, to find the most accurate and rapid test. In total, 105 skin scraping smears were taken from suspected dermal lesions of patients belonging to two known endemic CL areas, Gonbad and Bam districts, in Iran. Subsequently, the specimens were analyzed with microscopic, conventional PCR, and HRM-PCR techniques.

RESULTS

Most positive samples (89.5%) were observed using HRM-PCR, and among the three techniques, HRM-PCR was the most sensitive (89%, 95% CI 81-94) technique. Microscopic examination test had the lowest sensitivity (57%, 95% CI 47-66%). The highest agreement among positive samples was observed between HRM-PCR and conventional PCR tests.

DISCUSSION

Our results showed that the HRM-PCR technique is the most accurate and sensitive test for recognizing CL, and also a valuable alternative test for conventional PCR to detect various species.

Prevalence of cutaneous leishmaniasis infection and clinico-epidemiological patterns among military personnel in Mullaitivu and Kilinochchi districts of the Northern Province, early war-torn areas in Sri Lanka

BACKGROUND

The 30-year-old armed conflict in Sri Lanka resulted in a general breakdown of civil administration in the Northern and Eastern provinces, leading to mobilisation of many armed forces personnel to assist with reconstruction and resettlement. This occupational group has been identified as a priority risk group for leishmaniasis.

METHODS

Individuals enlisted at all military establishments in Mullaitivu and Kilinochchi districts, Northern Province of Sri Lanka were included. Five thousand individuals were screened for skin lesions between September 2018 and August 2019. Persons with lesions suspected as cutaneous leishmaniasis (CL) were further investigated. Information on sociodemographic/other potential risk factors was obtained through an interviewer-administered structured questionnaire. The diagnosis was confirmed by microscopic visualization of parasitic stages from different samples obtained (skin scraping, lesion aspirate and tissue impression smears), histopathology and polymerase chain reaction DNA amplification.

RESULTS

Among 5000 individuals screened, 74 individuals were suspected of having CL. Of these, 67.6% (n = 50) patients were confirmed for CL by microscopy. Around two third of both males (67.6%; n = 48) and females (66.6%; n = 2) were positive for Leishmania. The soldiers belonging to 26-35-year age group reported the highest susceptibility (83.3%; OR: 4.83, 95% CI: 3.49-6.20%). Of the sociodemographic factors, age, wearing short-sleeved upper body clothing as the uniform and non-use of insect repellents were identified as significant risk factors. Most of the CL patients had a single lesion (86.0%; n = 43) of an ulcerative type (34.0%; n = 17), mostly on their upper limb (67.9%; n = 34). Lesions were mostly 5-10 mm diameter (59.9%; n = 30) in size with poorly defined margins (72.0%; n = 36). Amongst the diagnostic techniques, microscopic examination of slit skin smear and tissue impression smear were able to discriminate the majority of patients (92.1%; n = 46) for CL.

CONCLUSIONS

In order to highlight the true burden of leishmaniasis in the military personnel, cases of leishmaniasis from military institutes should be recognized as a different entity per say and be included in the national figures so as to depict the real magnitude of the disease burden amongst this high-risk group.

Tissue and blood protozoa including toxoplasmosis, Chagas disease, leishmaniasis, Babesia, Acanthamoeba, Balamuthia, and Naegleria in solid organ transplant recipients- Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of tissue and blood protozoal infections in the pre- and post-transplant period. Significant new developments in the field have made it necessary to divide the previous single guideline published in 2013 into two sections, with the intestinal parasites separated from this guideline devoted to tissue and blood protozoa. The current update reflects the increased focus on donor screening and risk-based recipient monitoring for parasitic infections. Increased donor testing has led to new recommendations for recipient management of Toxoplasma gondii and Trypanosoma cruzi. Molecular diagnostics have impacted the field, with access to rapid diagnostic testing for malaria and polymerase chain reaction testing for Leishmania. Changes in Babesia treatment regimens in the immunocompromised host are outlined. The risk of donor transmission of free-living amebae infection is reviewed. Changing immigration patterns and the expansion of transplant medicine in developing countries has contributed to the recognition of parasitic infections as an important threat to transplant outcomes. Medications such as benznidazole and miltefosine are now available to US prescribers as access to treatment of tissue and blood protozoa is increasingly prioritized.

Evaluation of microcapillary culture method for the isolation of Leishmania aethiopica parasites from patients with cutaneous lesions in Ethiopia

BACKGROUND

In addition to direct slide microscopy, traditional culture method (TCM) has long been considered as a gold standard method for the diagnosis of cutaneous leishmaniasis (CL). However, TCM is relatively expensive and time-consuming compared to the newly introduced microculture method (MCM), which has shown to be sensitive and rapid diagnostic method elsewhere for different Leishmania parasite species other than Leishmania (L.) aethiopica. The objective of this study was to evaluate the diagnostic performance of MCM for the diagnosis of CL caused by L. aethiopica.

METHODS

One hundred forty-three lesion aspirates were collected from 124 suspected CL patients prospectively based on their consecutive series. Portion of the aspirates were cultured in duplicate in TCM with modified Novy-MacNeal-Nicolle (NNN) in tissue culture flask and microcapillary tubes containing RPMI 1640 with 10% fetal bovine serum (FBS) for MCM. Smears on glass slides from the remaining portion of the aspirate were used for direct microscopy to detect the parasite after stained with Giemsa staining solution. Up on a consensus, positive result in any two of the three tests was used as a reference standard to analyze sensitivity.

RESULTS

As per consensus standard criteria, 52 of the lesions were qualified to evaluate MCM versus TCM. Forty-eight lesion samples were positive by MCM, 36 by TCM, and 37 by smear microscopy. The representative DNA from parasite culture isolates revealed the causative Leishmania parasite was L. aethiopica by ITS1 polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Culturing L. aethiopica in vitro by MCM is more sensitive (92.3%) than by TCM (69.2%), P = 0.003. The median time for L. aethiopica promastigotes emergence in the culture was 3 days for MCM and 6 days for TCM, P < 0.001.

CONCLUSIONS

Our finding indicated that MCM is a sensitive and a rapid culturing method for the isolation of L. aethiopica than TCM and smear microscopy.

Molecular diagnosis of protozoan parasites by Recombinase Polymerase Amplification

Infections caused by protozoan parasites affect millions of people around the world. Traditionally, diagnosis was made by microscopy, which is insensitive and in some cases not specific. Molecular methods are highly sensitive and specific, but equipment costs and personnel training limit its availability only to specialized centers, usually far from populations with the highest risk of infection. Inexpensive methods that can be applied at the point of care (POC), especially in places with limited health infrastructure, would be a major advantage. Isothermal amplification of nucleic acids does not require thermocyclers and is relatively inexpensive and easy to implement. Among isothermal methods, recombinase polymerase amplification (RPA) is sensitive and potentially applicable at POC. We and others have developed RPA diagnostic tests to detect protozoan parasites of medical importance. Overall, our results have shown high specificity with limits of detection similar to PCR. Currently, the optimization of RPA for use at the POC is under development, and in the near future the tests should become available to detect protozoan infections in the field. In this review we discuss the current status, challenges, and future of RPA in the field of molecular diagnosis of protozoan parasites.

Evaluation of fluorimetry and direct visualization to interpret results of a loop-mediated isothermal amplification kit to detect Leishmania DNA

Background

Nucleic acid amplification tests (NAATs) have proven to be advantageous in the diagnosis of leishmaniases, allowing sensitive diagnosis of: (i) cutaneous leishmaniasis in long duration lesions and (ii) visceral leishmaniasis using a less-invasive sample like peripheral blood, in opposition to tissue aspiration required for parasite demonstration by microscopy. Despite their benefits, the implementation of NAATs for leishmaniasis diagnosis at the point-of-care has not been achieved yet, mostly due to the complexity and logistical issues associated with PCR-based methods.

Methods

In this work, we have evaluated the performance of a ready-to-use loop-mediated isothermal amplification (LAMP) kit using two real time fluorimeters to amplify leishmanial DNA obtained by silica column-based and Boil & Spin protocols.

Results

The different approaches used to run and interpret the LAMP reactions showed a performance equivalent to PCR and real-time PCR, using spiked and clinical samples. The time to positivity obtained with real-time fluorimetry showed an excellent correlation with both Ct values and parasite load from real-time quantitative PCR.

Conclusions

The results obtained open the possibility of using a highly stable, ready-to-use LAMP kit for the accurate diagnosis of leishmaniasis at the point-of-care. Furthermore, the feasibility of relating time to positivity, determined with a portable real-time fluorimeter, with the parasite burden could have a wider application in the management of leishmaniasis, such as in treatment efficacy monitoring or as a pharmacodynamics tool in clinical trials.

Clinical and epidemiological characteristics of cutaneous leishmaniasis in Sri Lanka

Background

Leishmaniasis, a vector borne tropical/subtropical disease caused by the protozoan Leishmania is transmitted to humans by sandfly vectors Phlebotomus and Lutzomyia. The principal form found in Sri Lanka is cutaneous leishmaniasis (CL) and is caused by Leishmania donovani. A rising trend in disease prevalence has been observed recently in Sri Lanka and the island is in fact the newest endemic focus in South Asia. Determining the prevalence of smear positivity among clinically suspected CL patients, identifying risk factors and specific clinical presentations of CL in order to implement preventive and early treatment strategies were the objectives of this study.

Methods

A sample of 509 clinically suspected cases of CL referred to the Department of Parasitology from all across Sri Lanka between 2005 and 2015 was selected consecutively. Diagnosis was confirmed by microscopic visualization of the Leishmania amastigote from the slit skin smear. A structured questionnaire was used to identify exposure related risk factors and a clinical examination was performed to identify lesion characteristics.

Results

Out of 509 clinical cases, 41.5% (n = 211) were smear positive. The study population ranged from ages 1 to 80 years (mean age = 34.76) and the most affected age group was 40–49. Of the smear positives, 58.85% were males. Majority (47.86%) were from the North Western region (Kurunegala) of the country and were exposed to scrub jungles. Sand fly exposure (p = 0.04) and positive contact history (p = 0.005) were significant risk factors for smear positivity.

Erythema (p = 0.02), lack of pruritus (p = 0.02) and scaly appearance (p = 0.003) were significant lesion characteristics in smear positivity. Lesions were commonly found in the exposed areas and the commonest morphological type was papulo-nodular.

Conclusions

An increasing trend in the spread of cutaneous leishmaniasis from endemic to non-endemic areas has become evident. Positive contact history and sandfly exposure were significant risk factors for smear positivity which may indicate the possibility of human reservoir hosts in infection transmission. Lack of pruritus, scaly appearance and erythema were highly significant lesion characteristics associated with Leishmania positive smears which can be used for the clinical diagnosis of CL.

Analytical Performance of Four Polymerase Chain Reaction (PCR) and Real Time PCR (qPCR) Assays for the Detection of Six Leishmania Species DNA in Colombia

Leishmaniasis comprises a spectrum of parasitic diseases caused by protozoans of the genus Leishmania. Molecular tools have been widely employed for the detection of Leishmania due to its high sensitivity and specificity. However, the analytical performance of molecular platforms as PCR and real time PCR (qPCR) including a wide variety of molecular markers has never been evaluated. Herein, the aim was to evaluate the analytical performance of 4 PCR-based assays (designed on four different targets) and applied on conventional and real-time PCR platforms. We evaluated the analytical performance of conventional PCR and real time PCR, determining exclusivity and inclusivity, Anticipated Reportable Range (ARR), limit of detection (LoD) and accuracy using primers directed to kDNA, HSP70, 18S and ITS-1 targets. We observed that the kDNA was the most sensitive but does not meet the criterion of exclusivity. The HSP70 presented a higher LoD in conventional PCR and qPCR in comparison with the other markers (1 × 10¹ and 1 × 10^-1 equivalent parasites/mL respectively) and had a higher coefficient of variation in qPCR. No statistically significant differences were found between the days of the test with the four molecular markers. The present study revealed that the 18S marker presented the best performance in terms of analytical sensitivity and specificity for the qPCR in the species tested (species circulating in Colombia). Therefore, we recommend to explore the analytical and diagnostic performance in future studies using a broader number of species across America.

Use of Recombinant Antigens for Sensitive Serodiagnosis of American Tegumentary Leishmaniasis Caused by Different Leishmania Species

American tegumentary leishmaniasis (ATL) (also known as cutaneous leishmaniasis [CL]) is caused by various species of protozoa of the genus Leishmania. The diagnosis is achieved on a clinical, epidemiological, and pathological basis, supported by positive parasitological exams and demonstration of leishmanin delayed-type hypersensitivity. Serological assays are not routinely used in the diagnosis because many are considered to have low sensitivity and the particular Leishmania species causing the disease can lead to variable performance. In the present study, we generated recombinant versions of two highly conserved Leishmania proteins, Leishmania (Viannia) braziliensis-derived Lb8E and Lb6H, and evaluated both in enzyme-linked immunosorbent assays (ELISA). Recombinant Lb6H (rLb6H) had better performance and reacted with 100.0% of the ATL and 89.4% of the VL samples. These reactions with rLb6H were highly specific (98.5%) when compared against those for samples from healthy control individuals. We then assessed rLb6H against sera from ATL patients infected with different species of Leishmania prevalent in Brazil [Leishmania (Leishmania) amazonensis, L. (Viannia) braziliensis, and L. (V.) guyanensis] and samples from patients with other infectious diseases. In analyses of 500 sera, ELISA using rLb6H detected all 219 ATL samples (sensitivity of 100.0%) with an overall specificity of 93.9% (considering healthy individuals and other infectious diseases patients). Only a minority of samples from Chagas disease patients possessed antibodies against rLb6H, and all of these responses were low (with a highest reactivity index of 2.2). Taken together, our data support further evaluation of rLb6H and the potential for its routine use in the serological diagnosis of ATL.

Diagnosis and Treatment of Leishmaniasis: Clinical Practice Guidelines by the Infectious Diseases Society of America (IDSA) and the American Society of Tropical Medicine and Hygiene (ASTMH)

It is important to realize that leishmaniasis guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. The IDSA and ASTMH consider adherence to these guidelines to be voluntary, with the ultimate determinations regarding their application to be made by the physician in the light of each patient's individual circumstances.

Evaluation of the reference value for the Montenegro skin test

INTRODUCTION

The Montenegro skin test (MST) has good clinical applicability and low cost for the diagnosis of American tegumentary leishmaniasis (ATL). However, no studies have validated the reference value (5mm) typically used to discriminate positive and negative results. We investigated MST results and evaluated its performance using different cut-off points.

METHODS

The results of laboratory tests for 4,256 patients with suspected ATL were analyzed, and 1,182 individuals were found to fulfill the established criteria. Two groups were formed. The positive cutaneous leishmaniasis (PCL) group included patients with skin lesions and positive direct search for parasites (DS) results. The negative cutaneous leishmaniasis (NCL) group included patients with skin lesions with evolution up to 2 months, negative DS results, and negative indirect immunofluorescence assay results who were residents of urban areas that were reported to be probable sites of infection at domiciles and peridomiciles.

RESULTS

The PCL and NCL groups included 769 and 413 individuals, respectively. The mean ± standard deviation MST in the PCL group was 12.62 ± 5.91mm [95% confidence interval (CI): 12.20-13.04], and that in the NCL group was 1.43 ± 2.17mm (95% CI: 1.23-1.63). Receiver-operating characteristic curve analysis indicated 97.4% sensitivity and 93.9% specificity for a cut-off of 5mm and 95.8% sensitivity and 97.1% specificity for a cut-off of 6mm.

CONCLUSIONS

Either 5mm or 6mm could be used as the cut-off value for diagnosing ATL, as both values had high sensitivity and specificity.

A Novel Molecular Test to Diagnose Canine Visceral Leishmaniasis at the Point of Care

Dogs are the principal reservoir hosts of zoonotic visceral leishmaniasis (VL) but current serological methods are not sensitive enough to detect all subclinically infected animals, which is crucial to VL control programs. Polymerase chain reaction (PCR) methods have greater sensitivity but require expensive equipment and trained personnel, impairing its implementation in endemic areas. We developed a diagnostic test that uses isothermal recombinase polymerase amplification (RPA) to detect Leishmania infantum. This method was coupled with lateral flow (LF) reading with the naked eye to be adapted as a point-of-care test. The L. infantum RPA-LF had an analytical sensitivity similar to real time-PCR, detecting DNA of 0.1 parasites spiked in dog blood, which was equivalent to 40 parasites/mL. There was no cross amplification with dog or human DNA or with Leishmania braziliensis, Leishmania amazonensis, or Trypanosoma cruzi. The test also amplified Leishmania donovani strains (N = 7). In a group of clinically normal dogs (N = 30), RPA-LF detected more subclinical infections than rK39 strip test, a standard serological method (50% versus 13.3% positivity, respectively; P = 0.005). Also, RPA-LF detected L. infantum in noninvasive mucosal samples of dogs with a sensitivity comparable to blood samples. This novel molecular test may have a positive impact in leishmaniasis control programs.

Cutaneous Leishmaniasis in dogs: is high seroprevalence indicative of a reservoir role?

American cutaneous leishmaniasis (ACL) is a complex disease with a rich diversity of animal host species. This diversity imposes a challenge, since understanding ACL transmission requires the adequate identification of reservoir hosts, those species able to be a source of additional infections. In this study we present results from an ACL cross-sectional serological survey of 51 dogs (Canis familiaris), where we used diagnostic tests that measure dog's exposure to Leishmania spp. parasites. We did our research in Panamá, at a village that has undergone significant ecosystem level transformations. We found an ACL seroprevalence of 47% among dogs, and their exposure was positively associated with dog age and abundance of sand fly vectors in the houses of dog owners. Using mathematical models, which were fitted to data on the proportion of positive tests as function of dog age, we estimated a basic reproductive number (R 0 ± s.e.) of 1·22 ± 0·09 that indicates the disease is endemically established in the dogs. Nevertheless, this information by itself is insufficient to incriminate dogs as ACL reservoirs, given the inability to find parasites (or their DNA) in seropositive dogs and previously reported failures to experimentally infect vectors feeding on dogs with ACL parasites.

Complementary exams in the diagnosis of American tegumentary leishmaniasis

The diagnosis of American Tegumentary Leishmaniasis is a difficult but essential task when considering the high toxicity profile of the drugs available. Since the discovery of its etiologic agent, numerous diagnostic tests have been developed. None of the tests available today can be considered as the gold standard, since they do not add enough accuracy for the disease detection. Good epidemiological and clinical knowledge of the disease are fundamental precepts of the dermatology practice and precede the rational use of existing diagnostic tests. In this article we aim, through extensive literature review, to recall fundamental concepts of any diagnostic test. Subsequently, based on this information, we will weave important comments about the characteristics of existing diagnostic tests, including immunological tests such as Montenegro's skin test, serology and detection of parasites by direct examination, culture or histopathology. Finally we will discuss the new technologies and options for the diagnosis of Cutaneous Leishmaniasis. The molecular biology technique is considered a promising tool, promoting the rapid identification of the species involved. We also aim to educate dermatologists about a disease with high morbidity and assist in its difficult recognition.

Improving Leishmania species identification in different types of samples from cutaneous lesions

The discrimination of Leishmania species from patient samples has epidemiological and clinical relevance. In this study, different gene target PCR-restriction fragment length polymorphism (RFLP) protocols were evaluated for their robustness as Leishmania species discriminators in 61 patients with cutaneous leishmaniasis. We modified the hsp70-PCR-RFLP protocol and found it to be the most reliable protocol for species identification.

Applicability of kDNA-PCR for routine diagnosis of American tegumentary leishmaniasis in a tertiary reference hospital

SUMMARY

This study evaluated the applicability of kDNA-PCR as a prospective routine diagnosis method for American tegumentary leishmaniasis (ATL) in patients from the Instituto de Infectologia Emílio Ribas (IIER), a reference center for infectious diseases in São Paulo - SP, Brazil. The kDNA-PCR method detected Leishmania DNA in 87.5% (112/128) of the clinically suspected ATL patients, while the traditional methods demonstrated the following percentages of positivity: 62.8% (49/78) for the Montenegro skin test, 61.8% (47/76) for direct investigation, and 19.3% (22/114) for in vitro culture. The molecular method was able to confirm the disease in samples considered negative or inconclusive by traditional laboratory methods, contributing to the final clinical diagnosis and therapy of ATL in this hospital. Thus, we strongly recommend the inclusion of kDNA-PCR amplification as an alternative diagnostic method for ATL, suggesting a new algorithm routine to be followed to help the diagnosis and treatment of ATL in IIER.

An improved microculture method for diagnosis of cutaneous leishmaniasis

This study evaluated the performance of three diagnostic methods for cutaneous leishmaniasis (CL). Patients who came to the Health Center Laboratory of Gonbad-e-Qabus in Golestan Province, Iran, were enrolled in the study. Skin scraping smear, improved microculture (IMC) and polymerase chain reaction (PCR) were performed. A total of 303 subjects were recruited, among whom 273 subjects fulfilled the criteria for CL. Sensitivity and specificity were 88.8 % (95 % CI = 84.2-92.2 %) and 100.0 % for smears, 98.4 % (95 % CI = 96.1-99.1 %) and 100.0 % for IMC, both of them 100.0 % for PCR. Although, PCR was relatively more sensitive than the IMC, the high correlation (agreement = 96 %, Kappa = 0.82) between IMC and PCR along with the advantages of simplicity, rapidity, adequate sensitivity and as a needle free method, offers the IMC as a valuable alternative diagnostic method for PCR in diagnosis of CL.

Methodology of clinical trials aimed at assessing interventions for cutaneous leishmaniasis

The current evidence-base for recommendations on the treatment of cutaneous leishmaniasis (CL) is generally weak. Systematic reviews have pointed to a general lack of standardization of methods for the conduct and analysis of clinical trials of CL, compounded with poor overall quality of several trials. For CL, there is a specific need for methodologies which can be applied generally, while allowing the flexibility needed to cover the diverse forms of the disease. This paper intends to provide clinical investigators with guidance for the design, conduct, analysis and report of clinical trials of treatments for CL, including the definition of measurable, reproducible and clinically-meaningful outcomes. Having unified criteria will help strengthen evidence, optimize investments, and enhance the capacity for high-quality trials. The limited resources available for CL have to be concentrated in clinical studies of excellence that meet international quality standards.

Solid evidence is needed to decide how to treat conditions. In the case of cutaneous leishmaniasis, the diversity of clinical conditions, combined with the heterogeneity and weaknesses of the methodologies used in clinical trials, make it difficult to derive robust conclusions as to which treatments should be used. There also other imperatives - ethical (not exposing patients to treatments that cannot be assessed adequately) and financial (optimize use of limited resources for a neglected condition). This paper is meant to provide clinical investigators with guidance for the design, conduct, analysis and report of clinical trials to assess the efficacy and safety of treatments of this condition.