Comparison of the specificity of PCR and the histopathological detection of leishmania for the diagnosis of American cutaneous leishmaniasis

Passive epidemiological surveillance in wildlife in Costa Rica identifies pathogens of zoonotic and conservation importance

Epidemiological surveillance systems for pathogens in wild species have been proposed as a preventive measure for epidemic events. These systems can minimize the detrimental effects of an outbreak, but most importantly, passive surveillance systems are the best adapted to countries with limited resources. Therefore, this research aimed to evaluate the technical and infrastructural feasibility of establishing this type of scheme in Costa Rica by implementing a pilot program targeting the detection of pathogens of zoonotic and conservation importance in wildlife. Between 2018 and 2020, 85 carcasses of free-ranging vertebrates were admitted for post-mortem and microbiology analysis. However, we encountered obstacles mainly related to the initial identification of cases and limited local logistics capacity. Nevertheless, this epidemiological surveillance scheme allowed us to estimate the general state of health of the country’s wildlife by establishing the causes of death according to pathological findings. For instance, 60% (51/85) of the deaths were not directly associated with an infectious agent. Though in 37.6% (32/85) of these cases an infectious agent associated or not with disease was detected. In 27.1% (23/85) of the cases, death was directly related to infectious agents. Furthermore, 12.9% (11/85), the cause of death was not determined. Likewise, this wildlife health monitoring program allowed the detection of relevant pathogens such as Canine Distemper Virus, Klebsiella pneumoniae, Angiostrongylus spp., Baylisascaris spp., among others. Our research demonstrated that this passive surveillance scheme is cost-effective and feasible in countries with limited resources. This passive surveillance can be adapted to the infrastructure dedicated to monitoring diseases in productive animals according to the scope and objectives of monitoring wildlife specific to each region. The information generated from the experience of the initial establishment of a WHMP is critical to meeting the challenges involved in developing this type of scheme in regions with limited resources and established as hotspots for emerging infectious diseases.

Molecular Diagnosis of Leishmaniasis: Quantification of Parasite Load by a Real-Time PCR Assay with High Sensitivity

Real-time PCR was developed to quantify Leishmania infantum kinetoplast DNA and optimized to achieve a sensitivity of 1 parasite/mL. For this purpose, we cloned the conserved kDNA fragment of 120 bp into competent cells and correlated them with serial dilutions of DNA extracted from reference parasite cultures calculating that a parasite cell contains approximately 36 molecules of kDNA. This assay was applied to estimate parasite load in clinical samples from visceral, cutaneous leishmaniasis patients and infected dogs and cats comparing with conventional diagnosis. The study aimed to propose a real-time PCR for the detection of Leishmania DNA from clinical samples trying to solve the diagnostic problems due to the low sensitivity of microscopic examination or the low predictive values of serology and resolve problems related to in vitro culture. The quantitative PCR assay in this study allowed detection of Leishmania DNA and quantification of considerably low parasite loads in samples that had been diagnosed negative by conventional techniques. In conclusion, this quantitative PCR can be used for the diagnosis of both human, canine and feline Leishmaniasis with high sensitivity and specificity, but also for evaluating treatment and the endpoint determination of leishmaniasis.

Accuracy of diagnostic tests for American tegumentary leishmaniasis: a systematic literature review with meta-analyses

OBJECTIVES

To analyse the accuracy of American tegumentary leishmaniasis (ATL) diagnostic methods and evaluate the quality of the existing publications by means of a systematic review.

METHODS

Diagnostic tests evaluated in at least two studies with common reference standards were included in the sensitivity and/or specificity meta-analyses. Quality and susceptibility to bias were analysed using the QUADAS-2 and STARD tools.

RESULTS

The title and abstract of 3387 publications were evaluated after deduplication resulting from database searches. Thirty-eight studies were included in the review, and 26 of them had results inserted in meta-analyses. The diagnostic methods with the highest pooled sensitivity values were ELISA, polymerase chain reaction (PCR), indirect immunofluorescence reaction and Montenegro's intradermal reaction. Cytometry was assessed in only two studies and presented 100% sensitivity in both. Smear slide microscopy and histopathology showed low pooled values of sensitivity. For specificity, the highest pooled values were identified for PCR. High values were also identified for ELISA, except for studies in which the reference standard for defining negative participants included individuals with Chagas' disease or paracoccidioidomycosis, which also occurred for cytometry. IFR had lower specificities than ELISA. There was a predominance of case-control designs of phase 1 or 2 and only four studies were strongly recommended as evidence generators. Several reference standards were adopted, and different methods were assessed in a small number of studies.

CONCLUSION

PCR showed the highest accuracy for the diagnosis of ATL, and its use should be encouraged in clinical practice. ELISA is recommended for the screening of suspected individuals, but the possibility of cross-reactions should be considered. New validation studies for the tests evaluated in few publications and studies of phase 3 with appropriate methods are needed.

A comparison of the efficiency of three sampling methods for use in the molecular and conventional diagnosis of cutaneous leishmaniasis

In human cutaneous leishmaniasis (CL), the success of positive diagnoses and species identifications depends, primarily, on how biopsies are taken and then processed and examined. The efficiency of three methods of taking skin biopsies from suspect cases of CL was compared using the classical methods of microscopy of stained smears, in vitro culture of tissue aspirate, and internal transcribed spacer region 1 (ITS1)-polymerase chain reaction in diagnosing positive cases and identifying the species of Leishmania causing them. From 1994-2014, biopsy samples from the skin lesions of 2232 CL-suspected patients were collected as unstained smears, as smears stained with Giemsa's stain and on filter paper, and compared in the diagnostic tests employed. Matched comparison based on testing biopsy samples from 100 patients, microscopy, in vitro culture and ITS1-PCR were also conducted to assess the most suitable combination of methods for diagnosing leishmaniases. In the 100-case-matched comparison, the three different types of sample proved to be equally good with no significant difference (P > 0.05). However, skin tissue imprints on filter paper revealed most cases of CL. The kappa statistic for measuring the degree of agreement among the three samples was 89%, which is considered good. Agreement was highest between imprints on filter paper and unstained smears, and lowest was for stained smears. In the overall comparison between the ITS1-PCR and conventional methods, the ITS1-PCR using samples from filter papers was the most sensitive method but the difference was insignificant (P = 0.32). The combination of microscopy together with ITS1-PCR on samples from filter papers increased the sensitivity significantly to 46%, compared to using the methods individually (P = 0.003-0.0008). On comparing the results of the tests done on the samples from the 2232 patients after applying ITS1-PCRs to their samples from filter papers, unstained smears, in vitro culture, microscopy, and stained smears showed, respectively, test sensitivities of 81, 69, 64, 57 and 48%. Of the tests and samples adjudicated, ITS1-PCRs run on skin tissue samples from filter papers proved best for the routine laboratory diagnosis of CL. Adding microscopy of stained smears to it, improved its diagnostic value significantly.

Field Validation of SYBR Green- and TaqMan-Based Real-Time PCR Using Biopsy and Swab Samples To Diagnose American Tegumentary Leishmaniasis in an Area Where Leishmania (Viannia) braziliensis Is Endemic

The precise diagnosis of American tegumentary leishmaniasis (ATL) is an essential task due to the disease's associated morbidity. A noninvasive, extremely sensitive, and highly specific exam is critical, particularly for mucosal leishmaniasis (ML), in which a low parasite quantity is expected. We aimed to compare the diagnostic accuracy of swab and biopsy sample analysis using SYBR Green- and TaqMan-based real-time PCR (qPCR) assays with that of a composite reference standard consisting of the Montenegro skin test, serology, histopathology, smears, culture, and conventional PCR. In total, 55 patients with ATL (ML, 18 patients; cutaneous leishmaniasis [CL], 37 patients) and 36 patients without ATL were studied. qPCR analysis of swabs was more accurate when using SYBR Green (87.88%; 95% confidence interval [CI], 77.86 to 93.73 patients) than when using TaqMan (78.79%; 95% CI, 67.49 to 86.92%) (P = 0.031). SYBR Green (84.72%; 95% CI, 74.68 to 91.25%) was also more accurate than TaqMan (73.61%; 95% CI, 62.42 to 82.41%) for biopsy samples (P = 0.008). All qPCR methods were 100% specific. Swabs and biopsy specimens had similar sensitivity when using the same chemistry (P = 0.125 for SYBR Green and P = 0.625 for TaqMan). Moreover, qPCR achieved better performance than most existing techniques used for the diagnosis of ATL and also detected the Leishmania parasite in a greater proportion of patients than the associated histopathology, smear, culture, and conventional PCR techniques did. Swabs therefore represent a useful diagnostic tool because they not only are noninvasive but also can achieve an accuracy similar to that of biopsy samples. The high accuracy of SYBR Green-based qPCR may also reduce the requirement for associated parasitological tests for ATL diagnosis.

Molecular Epidemiological Survey of Cutaneous Leishmaniasis in Two Highly Endemic Metropolises of Iran, Application of FTA Cards for DNA Extraction From Giemsa-Stained Slides

Background:

PCR has been used for confirmation of leishmaniasis in epidemiological studies, but complexity of DNA extraction and PCR approach has confined its routine use in developing countries.

Objectives:

In this study, recent epidemiological situation of cutaneous leishmaniasis (CL) in two hyper-endemic metropolises of Shiraz and Isfahan in Iran was studied using DNA extraction by commercial FTA cards and kinetoplastid DNA (kDNA)-PCR amplification for detection/identification of Leishmania directly from stained skin scraping imprints.

Patients and Methods:

Fifty four and 30 samples were collected from clinically diagnosed CL patients referred to clinical laboratories of leishmaniasis control centers in Isfahan and Shiraz cities, respectively. The samples were examined by direct microscopy and then scrapings of the stained smears were applied to FTA cards and used directly as DNA source in a nested-PCR to amplify kDNA to detect and identify Leishmania species.

Results:

Fifty four of 84 (64.2%) slides obtained from patients had positive results microscopically, while 79/84 (94%) of slides had positive results by FTA card-nested-PCR. PCR and microscopy showed a sensitivity of 96.4% and 64.2% and specificity of 100% and 100%, respectively. Interestingly, Leishmania major as causative agent of zoonotic CL was identified in 100% and 90.7% of CL cases from Isfahan and Shiraz cities, respectively, but L. tropica was detected from only 9.3% of cases from Shiraz city. All cases from central regions of Shiraz were L. tropica and no CL case was found in Isfahan central areas.

Conclusions:

Filter paper-based DNA extraction can facilitate routine use of PCR for diagnosis of CL in research and diagnostic laboratories in Iran and countries with similar conditions. Epidemiologic changes including dominancy of L. major in suburbs of Shiraz and Isfahan metropolises where anthroponotic CL caused by L. tropica had been established, showed necessity of precise studies on CL epidemiology in old urban and newly added districts in the suburbs.

Leishmaniasis: diagnostic issues in Europe

Leishmaniasis is a parasitic disease with clinical presentations that vary from asymptomatic infection to cutaneous, mucocutaneous or visceral disease. Recent epidemiological studies have shown an increased prevalence in Europe largely caused by an increase in international travel, difficulty eradicating leishmanial infection in AIDS patients, and the use of immunosuppressive medications. Clinical diagnosis may be challenging, and parasitological diagnosis entails the use of invasive procedures which may be unrevealing in the immunosuppressed. A number of less invasive tests for the detection of anti-leishmanial antibodies or leishmanial antigen are available but their sensitivity and specificity may vary with the infective species and results have to be interpreted in light of the clinical presentation. The availability of polymerase chain reaction assays amplifying leishmanial genetic material has been a major step forward in improving the diagnosis of leishmanial disease and the response to treatment.

Correlation between presence of Leishmania RNA virus 1 and clinical characteristics of nasal mucosal leishmaniosis

Introduction

Mucosal leishmaniosis (ML) is a severe clinical form of leishmaniosis. Complex factors related to the parasite and the host are attributed to the development of mucosal lesions. Leishmania RNA virus 1 (LRV1) can disrupt immune response, and may be the main determinant of severity of the disease; it should be investigated.

Objective

To study the existence of clinical differences between patients with ML with endosymbiosis by LRV1 and. those without it.

Methods

A cross-sectional cohort study with clinical evaluation, polymerase chain reaction (PCR) detection of Leishmania, species classification, and search of LRV1 was performed. Only patients with confirmed diagnosis of ML by positive PCR and with nasal mucosa injuries were included in this analysis.

Results

Out of 37 patients, 30 (81.1%) were diagnosed with Leishmania braziliensis, five (13.5%) with Leishmania guyanensis, and two (5.4%) with mixed infection of L. braziliensis and L. guyanensis. LVR1 virus was present in 26 (70.3%) of the cases.

Conclusion

Correlation between clinical phenotype and presence of LRV1 was not observed, although the frequency of the virus is two-fold higher in mucosal lesions than that found in the literature on skin lesions in the same geographical area.

Differentiation of Leishmania species by FT-IR spectroscopy

Leishmaniasis is a parasitic infectious disease caused by protozoa that belong to the genus Leishmania. It is transmitted by the bite of an infected female Sand fly. The disease is endemic in 88 countries Desjeux (2001) [1] (16 developed countries and 72 developing countries) on four continents. In Brazil, epidemiological data show the disease is present in all Brazilian regions, with the highest incidences in the North and Northeast. There are several methods used to diagnose leishmaniasis, but these procedures have many limitations, are time consuming, have low sensitivity, and are expensive. In this context, Fourier Transform Infrared Spectroscopy (FT-IR) analysis has the potential to provide rapid results and may be adapted for a clinical test with high sensitivity and specificity. In this work, FT-IR was used as a tool to investigate the promastigotes of Leishmaniaamazonensis, Leishmaniachagasi, and Leishmaniamajor species. The spectra were analyzed by cluster analysis and deconvolution procedure base on spectra second derivatives.

RESULTS

cluster analysis found four specific regions that are able to identify the Leishmania species. The dendrogram representation clearly indicates the heterogeneity among Leishmania species. The band deconvolution done by the curve fitting in these regions quantitatively differentiated the polysaccharides, amide III, phospholipids, proteins, and nucleic acids. L. chagasi and L. major showed a greater biochemistry similarity and have three bands that were not registered in L. amazonensis. The L. amazonensis presented three specific bands that were not recorded in the other two species. It is evident that the FT-IR method is an indispensable tool to discriminate these parasites. The high sensitivity and specificity of this technique opens up the possibilities for further studies about characterization of other microorganisms.

Accuracy of mucocutaneous leishmaniasis diagnosis using polymerase chain reaction: systematic literature review and meta-analysis

The diagnosis of mucocutaneous leishmaniasis (MCL) is hampered by the absence of a gold standard. An accurate diagnosis is essential because of the high toxicity of the medications for the disease. This study aimed to assess the ability of polymerase chain reaction (PCR) to identify MCL and to compare these results with clinical research recently published by the authors. A systematic literature review based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses: the PRISMA Statement was performed using comprehensive search criteria and communication with the authors. A meta-analysis considering the estimates of the univariate and bivariate models was performed. Specificity near 100% was common among the papers. The primary reason for accuracy differences was sensitivity. The meta-analysis, which was only possible for PCR samples of lesion fragments, revealed a sensitivity of 71% [95% confidence interval (CI) = 0.59; 0.81] and a specificity of 93% (95% CI = 0.83; 0.98) in the bivariate model. The search for measures that could increase the sensitivity of PCR should be encouraged. The quality of the collected material and the optimisation of the amplification of genetic material should be prioritised.

Diagnosis of cutaneous leishmaniasis: why punch when you can scrape?

Cutaneous leishmaniasis (CL) has been introduced to the Leishmania under-endemic Lebanese population in an uncontrolled manner as a result of recent large-scale displacement of refugees from endemic Syria. Accordingly, a quick and reliable method to diagnose CL is essential. Matched punch biopsies and air-dried scrapings on 72 patients were obtained. Scrapings were collected in two forms: thick drop (N = 33) or thin smear (N = 39). Clinical information was recorded. Sections of punch biopsies and scrapings were stained and examined microscopically. Polymerase chain reaction (PCR) was performed on both scraping forms and biopsies. The diagnostic sensitivity of the tests performed revealed that microscopy in conjunction with PCR on punch biopsies was the most sensitive test (93%) overall. However, taken individually, microscopy and PCR yielded the highest sensitivities when performed on drop scrapings (63% and 85%, respectively), and not smear scrapings (38% and 56%, respectively) as compared with the punch biopsies (44% and 83%, respectively). Microscopic concordance for punch biopsies and drop scrapings was present in 25 of 33 cases. Concordance was predicted only by the high/low parasitic index (PI: 3.1 ± 1.7 and 0.4 ± 0.5, respectively; P < 0.05). Herein, we optimized a novel rapid method for reliable diagnosis of CL based on drop scrapings with good agreement with the gold standard punch biopsy technique.

Detection of Leishmania (Viannia) IN Nyssomyia neivai and Nyssomyia whitmani by multiplex polymerase chain reaction, in Southern Brazil

Sandflies transmit pathogens of leishmaniasis. The natural infection of sandflies by Leishmania (Viannia) was assessed in municipalities, in the state of Paraná, in Southern Brazil. Sandflies were collected with Falcão and Shannon traps. After dissection in search of flagellates in digestive tubes and identification of the species, female sandflies were submitted to the Multiplex Polymerase Chain Reaction (multiplex PCR) for detection of the fragment of the kDNA of Leishmania (Viannia) and the fragment from the IVS6 cacophony gene region of the phlebotomine insects. The analysis was performed in pools containing seven to 12 guts from females of the same species. A total of 510 female sandflies were analyzed, including nine Migonemyia migonei, 17 Pintomyia fischeri, 216 Nyssomyia neivai, and 268 Nyssomyia whitmani. Although none of the females was found naturally infected by flagellates through dissection, the fragment of DNA from Leishmania (Viannia) was shown by multiplex PCR in one sample of Ny. neivai (0.46%) and three samples of Ny. whitmani (1.12%). It was concluded that Ny. neivai and Ny. whitmani are susceptible to Leishmania infection, and that multiplex PCR can be used in epidemiological studies to detect the natural infection of the sandfly vector, because of its sensitivity, specificity and feasibility.

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.

Diagnosis of American cutaneous leishmaniasis by enzyme immunoassay using membrane antigens of Leishmania (Viannia) braziliensis

This study evaluated the reactivity of membrane antigens of Leishmania (Viannia) braziliensis for the diagnosis of ACL by enzyme immunoassay (EIA). Promastigotes of L. (V.) braziliensis were grown in medium 199 and lysed in a sonicator. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting showed that specific proteins of L. (V.) braziliensis (apparent molecular weights 36 kDa and 48-56 kDa) were recognized by sera from ACL patients. These proteins were eluted from the SDS-PAGE and tested in EIA-IgG with sera from ACL patients, healthy individuals, patients with toxoplasmosis, paracoccidioidomycosis, syphilis, tuberculosis, leprosy, and Chagas disease. The EIA-IgG with membrane antigens allowed us to distinguish patients with ACL from healthy individuals and patients with other diseases (P < 0.0001), and showed a sensitivity of 93.3% and specificity of 90.8%, not including Chagas disease patients. 2D-SDS-PAGE followed by Western blotting was performed to improve the characterization of the antigens, and showed a component with isoelectric points near the acid pH side and apparent molecular weights of 48-56 kDa. The results showed good sensitivity and specificity of EIA-IgG with membrane antigens, indicating their potential use for diagnosis of ACL, as well as seroepidemiological surveys and follow-up of clinically cured patients.

Evaluation of PCR-RFLP (based on ITS-1 andHaeIII) for the detection ofLeishmaniaspecies, using Greek canine isolates and Jordanian clinical material

It is possible to detect and distinguish Leishmania parasites using PCR-RLFP - a combination of PCR and analysis of the fragment-length polymorphism seen when the amplicons are digested with one or more restriction enzymes. In the present study, clinical samples from 24 Jordanians suspected to have cutaneous leishmaniasis and cultures set up using leishmanial parasites from five Greek dogs were investigated using PCR, in which the internal-transcribed-spacer-1 (ITS1) region of the parasites' ribosomal-RNA gene was amplified, followed by HaeIII digestion of the resulting amplicons. The cultures, which were all maintained in Leibowitz L-15 medium with 20% foetal calf serum, were each investigated as serial dilutions. Using the PCR-RLFP analysis, each culture was identified as L. donovani and each was found positive for this parasite with a mean sensitivity of 66%-100% (depending on the culture dilution tested), a specificity of 100%, a mean positive predictive value of 100%, and a negative predictive value of 74.6%-100%. When simulated clinical samples, created by mixing human blood with known numbers of L. donovani promastigotes, were investigated, the PCR-RFLP gave optimal results (with a value of 100% each for sensitivity, specificity and positive and negative predictive values). When the real clinical samples (25 lesion aspirates and 20 samples of peripheral blood from 24 Jordanian patients) were investigated using the molecular method, 20 (84%) of the patients were found to have lesion aspirates that were PCR-RFLP-positive for L. major (although, by microscopy, only six were found to have amastigote-positive lesion aspirates). None of the blood samples from the Jordanian patients, however, was found PCR-positive.

Detection of DNA from Leishmania (Viannia): accuracy of polymerase chain reaction for the diagnosis of cutaneous leishmaniasis

Cutaneous leishmaniasis (CL) can occur in skin and mucosa, causing disfiguring lesions. The laboratory diagnosis of CL involves immunological methods and optical detection of the parasite, al of which have limitations. There is a need for more effective diagnostic methods for CL which wil allow treatment to be initiated more promptly in order to help prevent the development of severe forms of mucosal disease, and to estimate the prognosis of the infection. The polymerase chain reaction (PCR) has been widely used to diagnose CL, because of its higher sensitivity. This study estimated the accuracy and compared PCRs of samples from lesion scarification (PCR-L) and blood sample-enriched leukocytes (PCR-B) with three conventional diagnostic techniques: parasite direct search (DS), Montenegro skin test (MST), and indirect immunofluorescence reaction (IIF). The study included 276 patients under suspicion of CL. We conducted a cross-sectional study, in which patients were selected by convenience sampling. We used MP3H/MP1L primers to generate a Leishmania (Viannia) (minicircle kDNA) fragment of 70-bp. Of 106 patients with CL, 83.87%, 51.67%, 64.52%, 85.71%, or 96.10% tested positive by PCR-L, PCR-B, DS, IIF, or MST, respectively. Five patients tested positive only by PCR-L, and two other patients only by PCR-B. PCR-L is indicated for use in patients with chronic lesions or Leishmania reinfection, which may progress to mucosal lesion. PCR-B is indicated for use in patients with negative results in conventional tests or for patients with no apparent lesion. PCR is not only useful in diagnosing CL but also helps to identify the infecting species.

Proposal of a histopathological predictive rule for the differential diagnosis between American tegumentary leishmaniasis and sporotrichosis skin lesions

BACKGROUND

American tegumentary leishmaniasis (ATL) and sporotrichosis exhibit similar histopathology and low frequencies of microorganism detection.

OBJECTIVES

This study seeks to identify microscopic alterations that can distinguish between these diseases.

METHODS

Haematoxylin and eosin stained slides of 171 ATL and 97 sporotrichosis samples from active cutaneous lesions were examined for histopathological alterations. The lesions were diagnosed by isolating the agent (which was not visible) in culture. An intuitive diagnosis was assigned to each slide. The strength of the association between the histopathological findings and the diagnosis was estimated by an odds ratio, and each finding was graded according to a regression model. A score was assigned to each sample based on the histopathological findings. A study of the interobserver reliability was performed by calculating kappa coefficients of the histopathological findings and intuitive diagnoses.

RESULTS

The markers 'macrophage concentration', 'tuberculoid granuloma' and 'extracellular matrix degeneration' were associated with ATL. 'Suppurative granuloma', 'stellate granuloma', 'different types of giant cells', 'granulomas in granulation tissue' and 'abscess outside the granuloma' were associated with a diagnosis of sporotrichosis. 'Macrophage concentration' and 'suppurative granuloma' had the highest (substantial and almost perfect, respectively) reliability. The regression model score indicated 92.0% accuracy. The intuitive diagnosis had 82.5% diagnostic accuracy and substantial reliability.

CONCLUSIONS

Taking into account the clinical and epidemiological context, some histopathological alterations might be useful for the differential diagnosis between ATL and sporotrichosis cutaneous lesions in cases in which the aetiological agent is not visible.

Comparative analysis of the geographic distribution of the histopathological spectrum and Leishmania species of American cutaneous leishmaniasis in Brazil

BACKGROUND: Knowledge of the relationship between specific geographical differences and histopathology of the American cutaneous leishmaniasis is limited because host-parasite interactions in space and time are complex. OBJECTIVE: To describe the geographic analysis of the histopathological pattern of localized American cutaneous leishmaniasis and the relationship with Leishmania species. METHODS: A cross-sectional, descriptive and analytical study of a sample consisting of 55 patients of municipal districts of Montes Claros and 32 of Caratinga, Minas Gerais, by comparing with other endemic regions in Brazil, assessing historical and microregional data and developing confidence intervals. RESULTS: A preponderance of cellular exudative reactions in the cutaneous form of American cutaneous leishmaniasis was found in the municipal districts of Caratinga, east of Minas Gerais, Montes Claros, north of Minas Gerais and Uberlândia, Triangulo Mineiro, and also in the states of Mato Grosso and Ceara. Necrotic and exudative granulomatous reactions were found to be more frequent in the northern areas, mainly in the states of Amazonas and Para. Necrotic and exudative reactions were the most frequent form of presentation found throughout Brazil when the predominance of L. braziliensis was below 90% in relation to other species. CONCLUSION: There is a geographic variation of the immune inflammatory response in American cutaneous leishmaniasis. Geographical correlations between the predominant species of Leishmania and the most frequent forms of histopathological presentation of American cutaneous leishmaniasis, which until the present study had not been performed, enables new approaches to the study of Leishmania subpopulations in areas with a predominance of one species and provides evidence of variations in the biological behavior of different species.

Comparison of different primes for PCR-based diagnosis of cutaneous leishmaniasis

OBJECTIVE

The objective of this study was to analyze different primers that are commonly used in epidemiological studies for the detection of Leishmania DNA by PCR, and to compare them to the conventional direct parasite search for American cutaneous leishmaniasis (ACL) diagnosis.

MATERIAL AND METHODS

Five pairs of primers, four of them derived from Leishmania kDNA sequences (MP3H-MP1L; B1-B2; LBF1-LBR1; 13A-13B), and one derived from the SL RNA (mini-exon) gene repeat (LU5A-LB3C), reported previously, were used.

RESULTS

The MP3H-MP1L primers were the best at amplifying the DNA, detecting 2 fg of Leishmania spp. DNA. The 13A-13B primers presented the worst performance, detecting 512 x 10³ fg of DNA.

CONCLUSION

The wide variation in the analytical sensitivity of the primers used in the PCR, and the significant differences from the conventional method of ACL diagnosis found in this study, emphasize the importance of standardizing the PCR technique, analyzing sensitivity, and selecting suitable oligonucleotide primers.

[Canine tegumentar leishmaníasis in the town of Balneário Camboriú in the State of Santa Catarina]

INTRODUCTION

The increase in American tegumentary leishmaniasis (ATL) cases in 2005 was due to an outbreak that occurred in the towns of Itapema and Balneário Camboriú. This study aimed to determine the possible presence of infection by Leishmania sp in domestic dogs living in an endemic focus of ATL in the town of Balneário Camboriú and verify the existence of a correlation between the humoral and cellular immune responses, the presence of suggestive lesions and positivity in direct parasitological exams.

METHODS

A total of 275 dogs were evaluated, examined according to clinic aspects, the development of delayed hypersensitivity to Immunoleish antigens and serological responses to the indirect immunofluorescence reaction and immunoenzymatic assay.

RESULTS

Seven dogs presented suspect lesions, but Leishmania was not detected using the direct parasitological method. The serological result was 5.8% positivity using the IIFR technique, 6.2% by ELISA and 1.8% using the intradermal test. The total number of dogs positive for ATL using the serological exams and/or intradermal test was 24, indicating prevalence of 8.7% for ATL.

CONCLUSIONS

Further studies are required to evaluate the participation of dogs in the epidemiological chain of ATL in Balneário Camboriú.

Molecular detection of Leishmania braziliensis in Rattus norvegicus in an area endemic for cutaneous leishmaniasis in Brazil

Leishmania nested PCR (LnPCR) targeted to the SSUrRNA gene and DNA sequencing were used to analyze 315 tissue samples from 80 Rattus norvegicus specimens trapped in an area endemic for leishmaniasis in Belo Horizonte, Minas Gerais, Brazil. Of the samples analyzed, 17.46% (55/315) of all tissues, 10% (8/80) of skin, 26.92% (21/78) of blood, 30.76% (24/78) of bone marrow and 2.53% (2/79) of spleen were positive for Leishmania. The overall infection prevalence was 36.25% (29/80) The DNA sequencing showed that 65.51% (19/29) of the positive animals were infected by parasites belonging to the Leishmania braziliensis complex. The identification of L. braziliensis DNA in R. norvegicus in an area with a high prevalence of leishmaniasis might imply a zoonotic role of this species. The rodent control programs and health education may represent important measures toward the control of leishmaniasis.

Clinical, histopathologic, and cytologic diagnosis of mucosal leishmaniasis and literature review

CONTEXT

Mucosal leishmaniasis (ML) is a rare disease in the world, even in endemic areas such as Iran. Clinical, histologic, or cytologic assessment may help in the diagnosis of ML.

OBJECTIVE

To describe clinical, histologic, and cytologic findings in ML.

DESIGN

Review of our files showed 11 patients diagnosed with ML, of whom 7 patients had oral lesions, 1 of whom was a known patient with oral leishmaniasis with recurrence of oral lesions; 2 had laryngeal lesions; and 3 had nasal lesions. One case of laryngeal leishmaniasis was a recurrence of prior oral lesions. Cytologic smears were prepared by scraping the lesions with a scalpel or cytobrush. Histology on the biopsies was done for 7 patients. In 2 patients with nasal lesions, exfoliative cytology was made by washing the nasal cavity. Smears were both air dried and fixed in alcohol and stained.

RESULTS

Cytologic findings showed free Leishman-Donovan bodies, intrahistiocytic Leishman-Donovan bodies, atypical organisms, granuloma, acute and chronic inflammatory cells, histiocytes, multinucleated giant cells, mast cells, binucleated histiocytes (Reed-Sternberg-like cells), and plasma cells. In 6 of the patients, biopsy was inconclusive and in subsequent cytology the organism was detected. In 3 cases, findings from clinical and cytologic examinations were suggestive for leishmaniasis; however, with response to treatment, the diagnosis was confirmed. In 5 patients a malignant tumor was suspected because of clinical or histologic findings, but cytology helped to diagnose leishmaniasis.

CONCLUSIONS

Clinically or histologically, ML can be mistaken for benign and malignant lesions. Scraping or exfoliative cytology is an easy, reliable, and cost-effective method for diagnosing ML. Thus, clinical, histologic, and cytologic features together may help in ML diagnosis.

Usefulness of oral cytopathology in the diagnosis of infectious diseases

In recent years, the incidence of oral opportunistic infections has increased, partly due to the widespread implementation of organ and bone marrow transplantation and the increase in the prevalence of human immunodeficiency virus (HIV) infection. Cytology can be used as a rapid, inexpensive and simple routine procedure in diagnosing infectious diseases of the mouth. Moreover, ancillary methods can be applied to cytological samples, increasing the specificity and sensitivity for the diagnosis of infectious diseases. This review describes the cytopathological features of the main viral, fungal, bacterial and parasitic infections of the mouth. Cytological techniques of specimen collection, identification of infectious agents by cytomorphological approaches and ancillary methods, and diagnostic pitfalls will be discussed.

[Choice of primers: a determining element in molecular diagnosis of cutaneous leishmaniasis]

The cutaneous leishmaniasis (CL) is a parasitic disease which represents a serious problem for the public health not only in Tunisia but also all over the world. Its diagnosis is based on the techniques which are usually used, direct examination and in vitro culture. Because of several factors, these techniques lack sensitivity. The molecular biology, which is indeed more rapid and more sensitive, has proved its effectiveness in diagnosis of the CL. There are two main aims for our research work. First, to show the contribution of the Polymerase Chain Reaction (PCR) during the diagnosis of CL (of course by comparing the results obtained when using this technique with those found through the direct examination); second, to compare the two pairs of primers which amplify the leishmanien gene coding for the 18s ribosomal sub-unit: the pair R221/R332 (PCR1) and the pair Lei70L/Lei70R (PCR2). Our work was carried out upon 299 samples. One hundred and eighty-eight of them were positive using the direct examination and/or the PCR and 111 were negative. Only two samples were positive using of course the direct examination in comparison with 74 which were positive when using only the PCR (PCR1 and/or PCR2). Among these 74 samples, 64 where positive using only PCR2 in comparison with two samples which were positive using only PCR1. The eight remaining samples were at once positive for the PCR1 and the PCR2. The PCR (notably the PCR2) has proved a more significant percentage of positivity in comparison with direct examination: 98.98% for the PCR and 60.6% for direct examination.

L. (L.) chagasi in AIDS and visceral leishmaniasis (kala-azar) co-infection

Concomitant skin lesions in visceral leishmaniasis (VL) or kala-azar are rare, being more common the description of post-kala-azar dermal leishmaniasis occurring post treatment of kala-azar. Skin lesions caused by Leishmania donovani are frequently seen in the aids-VL co-infection. In Brazil cutaneous or mucosal forms of tegumentary leishmaniasis concomitant with aids are more commonly registered. Here we present a case of aids-VL co-infection, with unusual cutaneous and digestive compromising attributed to L. (L.) chagasi, with special attention to ecthymatous aspect of the lesion, allied to the absence of parasite on the histological skin biopsy.

DNA sequencing confirms the involvement of Leishmania (L.) amazonensis in American tegumentary leishmaniasis in the state of São Paulo, Brazil

INTRODUCTION

American tegumentary leishmaniasis (ATL) represents one of the most important public health issues in the world. An increased number of autochthonous cases of ATL in the Northeastern region of São Paulo State has been documented in the last few years, leading to a desire to determine the Leishmania species implicated.

METHODS

PCR followed by DNA sequencing was carried out to identify a 120bp fragment from the universal kDNA minicircle of the genus Leishmania in 61 skin or mucosal biopsies from patients with ATL.

RESULTS

DNA sequencing permitted the identification of a particular 15bp fragment (5' GTC TTT GGG GCA AGT... 3') in all samples. Analysis by the neighbor-joining method showed the occurrence of two distinct groups related to the genus Viannia (V) and Leishmania (L), each with two subgroups. Autochthonous cases with identity to a special Leishmania sequence not referenced in Genbank predominated in subgroup V.1, suggesting the possible existence of a subtype or mutation of Leishmania Viannia in this region. In the subgroup L.2, which showed identity with a known sequence of L. (L.) amazonensis, there was a balanced distribution of autochthonous and non-autochthonous cases, including the mucosal and mucocutaneous forms in four patients. The last observation may direct us to new concepts, since the mucosal compromising has commonly been attributed to L. (V.) braziliensis, even though L. (L.) amazonensis is more frequent in the Amazonian region.

CONCLUSIONS

These results confirm the pattern of distribution and possible mutations of these species, as well as the change in the clinical form presentation of ATL in the São Paulo State.

Evaluation of PCR assay in diagnosis and identification of cutaneous leishmaniasis: a comparison with the parasitological methods

The aims of this study are to identify Leishmania species and compare and validate internal transcribed spacers (ITS) polymerase chain reaction (PCR) assay against parasitological methods for diagnosing cutaneous leishmaniasis (CL). We used the ITS-PCR, parasite culture, and microscopic evaluation of stained smears on 155 specimens from suspected cases of (CL) patients who referred to Mashhad Health Centers (northeast Iran). The PCR indicated the sensitivity (98.8%), correctly diagnosing 86 of the 87 confirmed positive specimens. Microscopy and parasite culture alone showed 79.3% sensitivity (69/87 positive) and 86.2% sensitivity (75/87 positive), respectively, while microscopy and culture in combination improved sensitivity totally to 100% (87/87). The results also revealed that Leishmania tropica species is dominant (96.5%) in the studied regions. This study suggests that both the parasitological techniques reliably were used for the diagnosis of CL, and the ITS-PCR assay without using RFLP analysis is useful for identifying Leishmania species in the area.

Molecular diagnosis of leishmaniosis in the Paraná state of southern Brazil

The objective of the present study was to establish a polymerase chain reaction (PCR) technique for the diagnosis of cutaneous and mucocutaneous leishmaniosis from autochthonous cases in the state of Paraná in southern Brazil as well as imported cases. We sought to determine its utility and accuracy compared with smears and present culture methods. To standardize PCR samples, skin and mucosal punch biopsies from human lesions were performed on patients living in different regions of the Paraná state (76 cases) and other endemic areas of Brazil and Argentina (7 cases). For PCR standardization, two pairs of primers (MP1L/MP3H and B1/B2) were utilized for amplification of the conserved sequences in the minicircle of kinetoplast DNA (kDNA) for the Leishmania braziliensis complex. Two other primer pairs (b1/b2 and a1/a2) were species-specific for L. (V.) braziliensis and L. (V.) amazonensis, respectively. After differential diagnosis, eight patients had clinical diagnosis of the cutaneous ulcer changed to others pathologies such as syphilis, baso-cellular carcinoma, varicose ulcer, ecthyma and paracoccidioidomycosis. Of the 75 patients with cutaneous (CL) and mucocutaneous (MCL) lesions who provided samples, 47 (46 CL + 1 MCL) were diagnosed with leishmaniosis by smear and 57 (52 LC + 5 MCL) were diagnosed by culture methods. In contrast, our PCR technique presented higher accuracy when compared to the direct examination and culture of parasites. PCR is applicable both for CL where all 61 lesions were diagnosed, and MCL where 12 of 14 lesions were diagnosed. This molecular biology technique is also a faster and more specific diagnostic method compared with present parasitological procedures.

Biologia molecular aplicada às dermatoses tropicais

São apresentados conceitos básicos sobre célula, código genético e síntese protéica, e sobre algumas técnicas de biologia molecular, tais como PCR, PCR-RFLP, seqüenciamento de DNA, RT-PCR e immunoblotting. São fornecidos protocolos de extração de nucleotídeos e de proteínas, como salting out no sangue periférico e métodos do fenol-clorofórmio e do trizol em tecidos. Seguem-se exemplos comentados da aplicação de técnicas de biologia molecular para o diagnóstico etiológico e pesquisa em dermatoses tropicais, com ênfase na leishmaniose tegumentar americana e hanseníase.

Pesquisa de infecção natural de flebotomíneos por Leishmania, no Estado do Paraná

A leishmaniose tegumentar americana tem sido notificada em todos os estados do Brasil e no Paraná essa doença é endêmica. O objetivo deste trabalho foi detectar a infecção natural de flebotomíneos para verificar a competência vetorial destes insetos e a identificação da espécie parasitária. Os flebotomíneos foram coletados com armadilhas de Falcão e Shannon, nos municípios de Doutor Camargo, Fênix e Mandaguari, de novembro de 2005 a agosto de 2006. Coletaram-se 12.930 flebotomíneos, dos quais 2.487 fêmeas foram dissecadas e destes 1.230 fêmeas foram submetidas à reação em cadeia da polimerase. Pelo método da dissecação, foi detectada uma fêmea de Nyssomyia whitmani com infecção natural por flagelados e pela reação em cadeia da polimerase não se detectou a presença de DNA de Leishmania em nenhuma das fêmeas. Apesar de não ter sido detectada a infecção natural de Nyssomyia neivai nas localidades em apreço e ainda que os requisitos de incriminação vetorial não tenham sido atendidos, não se deve negligenciar o potencial vetorial desta espécie.

Polymerase chain reaction with two molecular targets in mucosal leishmaniasis' diagnosis: a validation study

We validated the polymerase chain reaction (PCR) with a composite reference standard in 61 patients clinically suspected of having mucosal leishmaniasis, 36 of which were cases and 25 were non-cases according to this reference standard. Patient classification and test application were carried out independently by two blind observers. One pair of primers was used to amplify a fragment of 120 bp in the conserved region of kDNA and another pair was used to amplify the internal transcript spacers (ITS) rDNA. PCR showed 68.6% (95% CI 59.2-72.6) sensitivity and 92% (95% CI 78.9-97.7) specificity; positive likelihood ratio: 8.6 (95% CI 2.8-31.3) and negative likelihood ratio: 0.3 (95% CI 0.3-0.5), when kDNA molecular target was amplified. The test performed better on sensitivity using this target compared to the ITS rDNA molecular target which showed 40% (95% CI 31.5-42.3) sensitivity and 96% (95% CI 84.1-99.3) specificity; positive likelihood ratio: 10 (95% CI 2.0-58.8) and negative likelihood ratio: 0.6 (95% CI 0.6-0.8). The inter-observer agreement was excellent for both tests. Based upon results obtained and due to low performance of conventional methods for diagnosing mucosal leishmaniasis, we consider PCR with kDNA as molecular target is a useful diagnostic test and the ITS rDNA molecular target is useful when the aim is to identify species.

Oral leishmaniasis: a clinicopathological study of 11 cases

Leishmaniasis is a parasitic disease with diverse clinical manifestations, and considered a public health problem in endemic countries such as Brazil. Mucosal lesions usually involve the upper respiratory tract, with a predilection for nose and larynx. Oral involvement is unusual and in most cases it becomes evident after several years of resolution of the original cutaneous lesions. Oral lesions classically appear as mucosal ulcerations, mainly in the hard or soft palate. This report describes the clinicopathological data of 11 cases of mucocutaneous leishmaniasis with oral manifestations. Two cases of Leishmania (Viannia) braziliensis and one case of Leishmania (Leishmania) amazonensis were confirmed by polymerase chain reaction-restriction fragment length polymorphism or DNA sequencing in mucosal samples.

Detection of Leishmania (Viannia) DNA in blood from patients with American cutaneous leishmaniasis

The aim of the present study was to investigate the presence of Leishmania (Viannia) subgenus DNA in peripheral blood from patients with cutaneous lesions due to American cutaneous leishmaniasis. The buffy coats from 68 blood samples were analyzed by polymerase chain reaction using the MP1L/MP3H primers. The parasite DNA was detected in 2 (3.4%) out of 59 patients who had amastigotes present in samples taken from lesions. The presence of Leishmania (Viannia) DNA in the blood of these patients indicates hematogeneous parasite dissemination.

Polymerase chain reaction with lesion scrapping for the diagnosis of human American tegumentary leishmaniasis

The objective of this work was to compare the polymerase chain reaction (PCR) using lesion scrapping with other conventional techniques for the diagnosis of the American tegumentary leishmaniasis (ATL). For this, patients with cutaneous lesions suspected to be ATL were studied. The DNA was amplified with the MP1L/MP3H primers. From the 156 studied patients, 79 (50.6%) presented positive parasite direct search (PD), 81 (51.9%) had positive Montenegro skin test (MST), and 90 (57.7%) presented PD and/or MST positive. The PCR was positive in all of the positive-PD patients (100% sensitivity), in 91.1% of the positive PD and/or MST patients, and in 27.3% of the patients that presented negative PD and positive MST. The PCR positivity was similar to the PD (P = 0.2482) and inferior to the MST (P = 0.0455), and to the PD/MST association (P = 0.0133). The high PCR sensitivity, and positivity in those cases where the PD was negative, highlights the importance of this technique as an auxiliary tool for the diagnosis of ATL.

Comparison of PCR assays for diagnosis of cutaneous leishmaniasis

Three PCR assays for diagnosing leishmaniasis were compared and validated against parasite cultures and microscopic evaluation of stained tissue smears using 92 specimens from suspected cases of cutaneous leishmaniasis (CL) in Israel and the West Bank. Samples from imported and locally acquired disease were examined. The kinetoplast DNA (kDNA) PCR showed the highest sensitivity (98.7%) of any assay, correctly diagnosing 77/78 of the confirmed positive samples, followed by the rRNA gene internal transcribed spacer 1 (ITS1) PCR (71/78 positive, 91.0% sensitivity) and then the spliced leader mini-exon PCR (42/78 positive, 53.8% sensitivity). Either parasite culture or microscopy alone detected 62.8% (49/78) or 74.4% (58/78) of the positive specimens, respectively, while culture and microscopy together improved overall sensitivity to 83.3% (65/78). Except for the kDNA PCR that had six false positives, all other assays were 100% specific. Further, restriction enzyme analysis of the ITS1 PCR product enabled identification of 74.6% of the positive samples, which included strains of Leishmania major (50.9%), Leishmania tropica (47.2%), and the Leishmania braziliensis complex (1.9%). This suggests that a PCR using kDNA should be used for the diagnosis of CL and that an ITS1 PCR can be reliably used for the diagnosis of CL when rapid species identification is needed.

Clinical diagnosis of cutaneous leishmaniasis: a comparison study between standardized graded direct microscopy and ITS1-PCR of Giemsa-stained smears

Parasitological diagnosis of cutaneous leishmaniasis is absolutely necessary before treatment. Direct microscopy of scrapings taken from the margins of skin lesions is the most commonly used method for clinical diagnosis of leishmaniasis. In this study to evaluate the usage of stained smears as samples for PCR and the possible advantage of PCR, we compared the sensitivity of the diagnosis of Giemsa-stained skin scrapings by standardized graded direct microscopy with that of ITS1-PCR with the material of the same area of the slide. Three 5mm x 5mm squares were marked on each of the 20 Giemsa-stained touch smears from 20 clinically diagnosed Palestinian patients. Out of the 60 squares scanned for amastigotes under 100x oil-immersion light microscopy, 45 (75%) gave usable results and 23 of these were positive for Leishmania. Fifteen (25%) squares could not be scanned microscopically, 12 because of staining that was too thick and 3 because of inadequate staining. DNA from each scanned square was extracted separately after microscopy and run through ITS1-PCR. Of the 23 microscopy-positive squares, 20 (87%) of these were positive by PCR. Of the three that were negative, one failed to extract for DNA, the second showed only one amastigote in the entire square, and the third was normally graded as +1 but was not amplified for unknown reasons. Of the 22 squares negative for microscopy, 18 (82%) were ITS1-PCR positive. Additionally, all three improperly stained squares were ITS1-PCR positive. Of the 12 darkly stained squares, 11 were positive. A negative control group of 15 German individuals from which Giemsa-stained slides containing three squares each was prepared and these slides were also microscopically scanned and tested by ITS1-PCR. Both tests were negative with both methods. Compared to microscopy (data in parenthesis), PCR showed a sensitivity of 87% (37%) and a specificity of 100% (100%). We have concluded that Giemsa-stained smears are a readily usable sampling method for PCR and that ITS1-PCR is far more sensitive than microscopy.

Métodos subsidiários para o diagnóstico da Leishmaniose tegumentar americana (LTA): comparação dos resultados do seqüenciamento de DNA e da PCR-RFLP para determinação da espécie de leishmania em amostras cutâneo-mucosas

FUNDAMENTOS: Métodos moleculares têm-se mostrados mais eficazes para o diagnóstico da LTA. OBJETIVOS: Comparar os resultados da intradermorreação de Montenegro (IRM), presença de leishmania em biópsia (Bc), reação de imunofluorescência indireta (Rifi), seqüenciamento de DNA e PCR-RFLP (-restriction fragment lenght polymorphism) para o diagnóstico da LTA. MÉTODOS: Foram estudados 152 pacientes com LTA. Para a PCR em Bc, utilizaram-se primers específicos para seqüência de 120bp do kDNA do minicírculo comum a todas as espécies de leishmanias. O produto da PCR, utilizado para seqüenciamento e para restrição enzimática com Hae III, foi comparado às culturas L. (L.) amazonensis e L. (V.) braziliensis. RESULTADOS: Houve predomínio do sexo masculino (75%), da cor branca (80%) e da profissão urbana (48%). A idade variou de três a 77 anos, com 56,5% entre 21 e 50 anos. 65,8% eram do Estado de São Paulo, prevalecendo a forma cutânea (79,6%). A IRM foi positiva em 73,4%, e a Rifi em 59,7%, enquanto a Bc evidenciou presença de leishmania em 30,6%. A PCR foi positiva em 81,6%, e a PCR-RFLP identificou L. (V.) braziliensis como espécie predominante (66%), o que também ocorreu com o seqüenciamento. Comparando PCR-RFLP e seqüenciamento, houve 61% de concordância entre os resultados, mostrando significância da PCR-RFLP para L. (V.) braziliensis. CONCLUSÕES: A IRM e a PCR foram estatisticamente equivalentes como métodos subsidiários para o diagnóstico da LTA, a PCR-RFLP e o seqüenciamento também o foram na identificação das espécies de leishmania, o primeiro apresentando menores custo e tempo de execução comparado ao seqüenciamento de DNA.

Usefulness of PCR in the diagnosis of cutaneous leishmaniasis in Tunisia

We assessed the efficiency of a PCR method in establishing the diagnosis of cutaneous leishmaniasis (CL) in Tunisian patients. Four hundred and thirty specimens collected passively from patients with cutaneous ulcers suggestive of leishmaniasis attending health centres for diagnosis were included in the study. Dermal scrapings were analysed both by parasitological (examination of Giemsa-stained smears and in vitro cultivation) methods and by a genus-specific PCR detecting a fragment of the 18S rRNA gene. Microscopy revealed amastigotes in 245 samples (57.0%) and in vitro cultivation gave positive results in 88 cases (20.5%), whereas PCR detected Leishmania in 301 samples (70%). The sensitivities inferred from our results were 99.3%, 80.8% and 29% for PCR, microscopic examination and in vitro cultivation, respectively. The different forms of CL in this country are caused by three species of Leishmania and are treated with the same protocol. Of 303 well-documented cases in our study, 99% were probably caused by Leishmania major and 1% by Leishmania infantum. The lack of species-specific diagnosis is not known to affect treatment or prognosis in Tunisia. These data support the incorporation of PCR into diagnostic strategies for CL, particularly in Tunisia.

Estudo clínico, epidemiológico e terapêutico de 402 pacientes com leishmaniose tegumentar americana atendidos no Hospital Universitário de Brasília, DF, Brasil

FUNDAMENTOS: A leishmaniose tegumentar americana é doença em expansão no Brasil. A região Centro-Oeste é hoje a terceira em incidência e a primeira em crescimento da doença. OBJETIVOS: Avaliar pacientes com leishmaniose tegumentar americana atendidos no Hospital Universitário de Brasília, quanto a aspectos clinicoepidemiológicos e resposta ao tratamento com antimonial pentavalente. MÉTODOS: Estudo do tipo série de casos de 402 pacientes, segundo sexo, idade, ocupação, procedência, formas clínicas, métodos de diagnóstico, tratamento com antimonial pentavalente e efeitos colaterais, no período de 1/1/1994 a 28/2/2003. O acompanhamento foi de um ano pós-tratamento. RESULTADOS: Predomínio de homens, lavradores, de 20 a 39 anos, com a forma cutânea. A eficácia do antimonial foi maior em pacientes com forma cutânea tratados até seis meses depois do início dos sintomas, e em pacientes do sexo feminino (diferenças estatisticamente significativas na análise multivariada). O mesmo ocorreu para pacientes com forma mucocutânea, mas sem diferença estatística significante. Alterações eletrocardiográficas foram mais freqüentes no grupo tratado com 20mg SbV/kg/dia por 30 dias em relação ao tratado por 20 dias. Eosinofilia ocorreu em 17,5% dos casos. CONCLUSÕES: Tratamento precoce, sexo feminino e a forma cutânea apresentaram índices mais elevados de cura. Alterações do eletrocardiograma aumentaram com o tempo de tratamento com antimoniais. A eosinofilia como efeito colateral ao uso do antimonial merece maior investigação.

Detection of Leishmania braziliensis in human paraffin-embedded tissues from Tucumán, Argentina by polymerase chain reaction

American cutaneous leishmaniasis (ACL) is an endemic disease in Northern Argentina. We applied the polymerase chain reaction (PCR) followed by a hybridization labelled probe to 21 paraffin embedded human skin biopsies, already analyzed histologically, from leishmaniasis endemic areas in the province of Tucumán, Argentina. We used primers previously designed to detect a Leishmania-specific 120-base-pair fragment of kinetoplast DNA minicircle, other two primer pairs that amplify kDNA minicircles belonging to the L. braziliensis and L. mexicana complexes respectively, and specific oligonucleotide primers to detect L. (V.) braziliensis which amplify the sequence of the ribosomal protein L-14 of this species. The PCR-hybridization showed a sensitivity of 90.5% when compared to the histopathology test which was 61.9%. Five of the total samples analyzed were positive for the L. braziliensis complex whilst none was positive for the L. mexicana complex. The specific primers for L. (V.) braziliensis detected the parasite in four samples. These results are consistent with those reported for close endemic areas and demonstrate that the causative agent of human leishmaniasis in the analyzed cases was L. (V.) braziliensis. PCR should be used as a diagnostic tool for tegumentary leishmaniasis, especially in the mucosal form, and as a valuable technique for the identification of the Leishmania species that causes the disease in certain areas.

Old world cutaneous leishmaniasis in Los Angeles: a case report, overview of the current literature, and guide for the treating dermatopathologist

We describe a case of cutaneous leishmaniasis in a Spanish patient visiting Los Angeles. Leishmania species cause both cutaneous and visceral disease; the majority of infections with Leishmania are of the cutaneous form. Although leishmaniasis is a relatively rare occurrence in the United States, travel by United States' citizens to endemic regions and increased United States military operations in the Middle East raise the chances of encountering cutaneous leishmaniasis. The following case report and overview of the current literature outlines the major morphologic findings and current diagnostic modalities available to diagnose cutaneous leishmaniasis.

Diagnosis of cutaneous leishmaniasis

PURPOSE OF REVIEW

The purpose of this review is to discuss some of the most important issues in the clinical and laboratory diagnosis of cutaneous leishmaniasis. The former is based on clinical experience and the latter on the literature published within the last couple of years. The sensitivity and specificity of old and novel tests to identify the parasite, antigenic products, the host's immune response, and the molecular diagnosis by the PCR are considered here.

RECENT FINDINGS

Recent clinical and laboratory research has addressed the individual, entomological, and epidemiological aspects of acute and chronic forms of cutaneous leishmaniasis. Traditional diagnostic investigations for individual cases include the search of suggestive history and clinical features, the identification of amastigotes by histology or direct microscopy, and the growth of promastigotes in culture. Diagnosis by the polymerase chain reaction seems to be approaching a 'gold standard' status as novel techniques offer considerable advantages in the collection and transport of specimens and DNA extraction procedures that are more efficient in individual and field-based protocols. Several authors have reported consistent 100% specificity with increasing sensitivity that overall is between 92 and 98%. Moreover the PCR approach makes possible the fast identification at the Leishmania species and subspecies level.

SUMMARY

The diagnostic tools discussed in this review are relevant not only for the diagnosis in endemic regions of the world but also for travellers and workers that following exposure return to non-endemic countries.