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Detecting Leishmania in dogs: A hierarchical-modeling approach to investigate the performance of parasitological and qPCR-based diagnostic procedures. PLoS Negl Trop Dis 2022; 16:e0011011. [PMID: 36525465 PMCID: PMC9803295 DOI: 10.1371/journal.pntd.0011011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 12/30/2022] [Accepted: 12/08/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Domestic dogs are primary reservoir hosts of Leishmania infantum, the agent of visceral leishmaniasis. Detecting dog infections is central to epidemiological inference, disease prevention, and veterinary practice. Error-free diagnostic procedures, however, are lacking, and the performance of those available is difficult to measure in the absence of fail-safe "reference standards". Here, we illustrate how a hierarchical-modeling approach can be used to formally account for false-negative and false-positive results when investigating the process of Leishmania detection in dogs. METHODS/FINDINGS We studied 294 field-sampled dogs of unknown infection status from a Leishmania-endemic region. We ran 350 parasitological tests (bone-marrow microscopy and culture) and 1,016 qPCR assays (blood, bone-marrow, and eye-swab samples with amplifiable DNA). Using replicate test results and site-occupancy models, we estimated (a) clinical sensitivity for each diagnostic procedure and (b) clinical specificity for qPCRs; parasitological tests were assumed 100% specific. Initial modeling revealed qPCR specificity < 94%; we tracked the source of this unexpected result to some qPCR plates having subtle signs of possible contamination. Using multi-model inference, we formally accounted for suspected plate contamination and estimated qPCR sensitivity at 49-53% across sample types and dog clinical conditions; qPCR specificity was high (95-96%), but fell to 81-82% for assays run in plates with suspected contamination. The sensitivity of parasitological procedures was low (~12-13%), but increased to ~33% (with substantial uncertainty) for bone-marrow culture in seriously-diseased dogs. Leishmania-infection frequency estimates (~49-50% across clinical conditions) were lower than observed (~60%). CONCLUSIONS We provide statistical estimates of key performance parameters for five diagnostic procedures used to detect Leishmania in dogs. Low clinical sensitivies likely reflect the absence of Leishmania parasites/DNA in perhaps ~50-70% of samples drawn from infected dogs. Although qPCR performance was similar across sample types, non-invasive eye-swabs were overall less likely to contain amplifiable DNA. Finally, modeling was instrumental to discovering (and formally accounting for) possible qPCR-plate contamination; even with stringent negative/blank-control scoring, ~4-5% of positive qPCRs were most likely false-positives. This work shows, in sum, how hierarchical site-occupancy models can sharpen our understanding of the problem of diagnosing host infections with hard-to-detect pathogens including Leishmania.
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Osiro Bergmann J, de Castro Moreira Dos Santos Júnior A, Sevilha-Santos L, Medeiros-Silva V, Bresolin Pompeu C, Youssif Mota Arabi A, da Silva Marques D, Caroline Véras de Carvalho B, Nitz N, Martins Gomes C, Dolabela de Lima B, Nonata Ribeiro Sampaio R. Accuracy of a TaqMan-based real-time polymerase chain reaction combined to a Novy-MacNeal-Nicolle medium culture for the diagnosis of American tegumentary leishmaniasis. J Eur Acad Dermatol Venereol 2019; 33:e188-e190. [PMID: 30659669 DOI: 10.1111/jdv.15440] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- J Osiro Bergmann
- Pós-graduação em Ciências Médicas, Faculdade de Medicina, Universidade de Brasília - UnB, Campus Universitário Darcy Ribeiro, Asa Norte, Brasília, DF 70.910-900, Brazil
| | - A de Castro Moreira Dos Santos Júnior
- Pós-graduação em Patologia Molecular, Faculdade de Medicina, Universidade de Brasília - UnB, Campus Universitário Darcy Ribeiro, Asa Norte, Brasília, DF 70.910-900, Brazil
| | - L Sevilha-Santos
- Pós-graduação em Ciências Médicas, Faculdade de Medicina, Universidade de Brasília - UnB, Campus Universitário Darcy Ribeiro, Asa Norte, Brasília, DF 70.910-900, Brazil
| | - V Medeiros-Silva
- Pós-graduação em Ciências da Saúde, Faculdade de Medicina, Universidade de Brasília - UnB, Campus Universitário Darcy Ribeiro, Asa Norte, Brasília, DF 70.910-900, Brazil
| | - C Bresolin Pompeu
- Serviço de Dermatologia, Hospital Universitário de Brasília - HUB, Universidade de Brasília - UnB, Campus Universitário Darcy Ribeiro, Asa Norte, Brasília, DF 70.910-900, Brazil
| | - A Youssif Mota Arabi
- Faculdade de Medicina, Universidade de Brasília - UnB, Campus Universitário Darcy Ribeiro, Asa Norte, Brasília, DF 70.910-900, Brazil
| | - D da Silva Marques
- Faculdade de Medicina, Universidade de Brasília - UnB, Campus Universitário Darcy Ribeiro, Asa Norte, Brasília, DF 70.910-900, Brazil
| | - B Caroline Véras de Carvalho
- Pós-graduação em Ciências Médicas, Faculdade de Medicina, Universidade de Brasília - UnB, Campus Universitário Darcy Ribeiro, Asa Norte, Brasília, DF 70.910-900, Brazil
| | - N Nitz
- Laboratório Interdisciplinar de Biociências, Pós-graduação em Patologia Molecular, Faculdade de Medicina, Universidade de Brasília - UnB, Campus Universitário Darcy Ribeiro, Asa Norte, Brasília, DF 70.910-900, Brazil
| | - C Martins Gomes
- Pós-graduação em Ciências Médicas, Faculdade de Medicina, Universidade de Brasília - UnB, Campus Universitário Darcy Ribeiro, Asa Norte, Brasília, DF 70.910-900, Brazil.,Serviço de Dermatologia, Hospital Universitário de Brasília - HUB, Universidade de Brasília - UnB, Campus Universitário Darcy Ribeiro, Asa Norte, Brasília, DF 70.910-900, Brazil.,Núcleo de Medicina Tropical, Pós-graduação em Ciências Médicas, Faculdade de Medicina, Universidade de Brasília - UnB, Campus Universitário Darcy Ribeiro, Asa Norte, Brasília, DF 70.910-900, Brazil.,Laboratório de Dermatomicologia, Faculdade de Medicina, Universidade de Brasília - UnB, Campus Universitário Darcy Ribeiro, Asa Norte, Brasília, DF 70.910-900, Brazil
| | - B Dolabela de Lima
- Laboratório de Biologia do Gene, Pós-graduação em Biologia Microbiana, Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília - UnB, Campus Universitário Darcy Ribeiro, Asa Norte, Brasília, DF 70.910-900, Brazil
| | - R Nonata Ribeiro Sampaio
- Laboratório de Dermatomicologia, Faculdade de Medicina, Universidade de Brasília - UnB, Campus Universitário Darcy Ribeiro, Asa Norte, Brasília, DF 70.910-900, Brazil
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Teixeira AIP, Silva DM, Vital T, Nitz N, de Carvalho BC, Hecht M, Oliveira D, Oliveira E, Rabello A, Romero GAS. Improving the reference standard for the diagnosis of canine visceral leishmaniasis: a challenge for current and future tests. Mem Inst Oswaldo Cruz 2019; 114:e180452. [PMID: 30726343 PMCID: PMC6358009 DOI: 10.1590/0074-02760180452] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 01/04/2019] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Studies aimed at validating canine visceral leishmaniasis diagnostic tests present heterogeneous results regarding test accuracy, partly due to divergences in reference standards used and different infection evolution periods in animals. OBJECTIVE This study aimed to evaluate the accuracy of the rapid test-dual path platform (TR-DPP) (Biomanguinhos®), EIE-Leishmaniose-Visceral-Canina-Biomanguinhos (EIE-LVC) (Biomanguinhos®), enzyme-linked immunosorbent assay (ELISA) rK39 (in-house), and the direct agglutination test (DAT-Canis) against a reference standard comprising parasitological and molecular techniques. METHODS A phase II/III validation study was carried out in sample sera from 123 predominantly asymptomatic dogs living in an area endemic for visceral leishmaniasis. FINDINGS Sixty-nine (56.1%) animals were considered infected according to the reference standard. For each test, the sensitivity and specificity, respectively, were as follows: TR-DPP, 21.74% [confidence interval (CI)95% 13.64% to 32.82%] and 92.59% (CI95% 82.45% to 97.08%); EIE-LVC, 11.59% (CI95% 5.9% to 21.25%) and 90.74% (CI95% 80.09% to 95.98%); ELISA rK39, 37.68% (CI95% 27.18% to 49.48%) and 83.33% (CI95% 71.26% to 90.98%); and DAT-Canis, 18.84% (CI95% 11.35% to 29.61%) and 96.30% (CI95% 87.46% to 98.98%). CONCLUSION We concluded that improving the sensitivity of serum testing for diagnosing asymptomatic dogs must constitute a priority in the process of developing new diagnostic tests to be used in the visceral leishmaniasis control program in Brazil.
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Affiliation(s)
| | | | - Tamires Vital
- Universidade de Brasília, Núcleo de Medicina Tropical, Brasília, DF, Brasil.,Universidade de Brasília, Faculdade de Medicina, Laboratório Interdisciplinar de Biociências, Brasília, DF, Brasil
| | - Nadjar Nitz
- Universidade de Brasília, Faculdade de Medicina, Laboratório Interdisciplinar de Biociências, Brasília, DF, Brasil
| | | | - Mariana Hecht
- Universidade de Brasília, Faculdade de Medicina, Laboratório Interdisciplinar de Biociências, Brasília, DF, Brasil
| | - Diana Oliveira
- Grupo de Pesquisas Clínicas e Políticas Públicas em Doenças Infecciosas e Parasitárias, Belo Horizonte, MG, Brasil
| | - Edward Oliveira
- Grupo de Pesquisas Clínicas e Políticas Públicas em Doenças Infecciosas e Parasitárias, Belo Horizonte, MG, Brasil
| | - Ana Rabello
- Grupo de Pesquisas Clínicas e Políticas Públicas em Doenças Infecciosas e Parasitárias, Belo Horizonte, MG, Brasil
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Diagnosis of Leishmania infection in a nonendemic area of South America. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2016; 49:809-812. [DOI: 10.1016/j.jmii.2014.11.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 11/29/2014] [Indexed: 11/22/2022]
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Medeiros-Silva V, Gurgel-Gonçalves R, Nitz N, Morales LEDA, Cruz LM, Sobral IG, Boité MC, Ferreira GEM, Cupolillo E, Romero GAS. Successful isolation of Leishmania infantum from Rhipicephalus sanguineus sensu lato (Acari: Ixodidae) collected from naturally infected dogs. BMC Vet Res 2015; 11:258. [PMID: 26452666 PMCID: PMC4600268 DOI: 10.1186/s12917-015-0576-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 10/06/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The main transmission route of Leishmania infantum is through the bites of sand flies. However, alternative mechanisms are being investigated, such as through the bites of ticks, which could have epidemiological relevance. The objective of this work was to verify the presence of Leishmania spp. in Rhipicephalus sanguineus sensu lato collected from naturally infected dogs in the Federal District of Brazil. METHODS Ticks were dissected to remove their intestines and salivary glands for DNA extraction and the subsequent amplification of the conserved region of 120 bp of kDNA and 234 bp of the hsp70 gene of Leishmania spp. The amplified kDNA products were digested with endonucleases HaeIII and BstUI and were submitted to DNA sequencing. Isolated Leishmania parasites from these ticks were analyzed by multilocus enzyme electrophoresis, and the DNA obtained from this culture was subjected to microsatellite analyses. RESULTS Overall, 130 specimens of R. sanguineus were collected from 27 dogs. Leishmania spp. were successfully isolated in culture from five pools of salivary glands and the intestines of ticks collected from four dogs. The amplified kDNA products from the dog blood samples and from the tick cultures, when digested by HaeIII and BstUI, revealed the presence of L. braziliensis and L. infantum. One strain was cultivated and characterized as L. infantum by enzyme electrophoresis. The amplified kDNA products from the blood of one dog showed a sequence homology with L. braziliensis; however, the amplified kDNA from the ticks collected from this dog showed a sequence homology to L. infantum. CONCLUSION The results confirm that the specimens of R. sanguineus that feed on dogs naturally infected by L. infantum contain the parasite DNA in their intestines and salivary glands, and viable L. infantum can be successfully isolated from these ectoparasites.
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Affiliation(s)
- Viviane Medeiros-Silva
- Programa de Pós-Graduação em Medicina Tropical, Universidade de Brasília, Brasília, DF, Brazil.
| | - Rodrigo Gurgel-Gonçalves
- Programa de Pós-Graduação em Medicina Tropical, Universidade de Brasília, Brasília, DF, Brazil. .,Laboratório de Parasitologia Médica e Biologia de Vetores, Universidade de Brasília, Brasília, DF, Brazil.
| | - Nadjar Nitz
- Programa de Pós-Graduação em Medicina Tropical, Universidade de Brasília, Brasília, DF, Brazil.
| | | | | | | | - Mariana Côrtes Boité
- Laboratório de Pesquisa em Leishmaniose, Coleção de Leishmania, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
| | - Gabriel Eduardo Melim Ferreira
- Laboratório de Pesquisa em Leishmaniose, Coleção de Leishmania, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
| | - Elisa Cupolillo
- Laboratório de Pesquisa em Leishmaniose, Coleção de Leishmania, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
| | - Gustavo Adolfo Sierra Romero
- Programa de Pós-Graduação em Medicina Tropical, Universidade de Brasília, Brasília, DF, Brazil. .,Laboratório de Leishmanioses, Núcleo de Medicina Tropical, Universidade de Brasília, Brasília, DF, Brazil.
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Gomes CM, Paula NAD, Morais OOD, Soares KA, Roselino AM, Sampaio RNR. Complementary exams in the diagnosis of American tegumentary leishmaniasis. An Bras Dermatol 2015; 89:701-9. [PMID: 25184908 PMCID: PMC4155947 DOI: 10.1590/abd1806-4841.20142389] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Accepted: 02/25/2013] [Indexed: 01/04/2023] Open
Abstract
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.
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Chusri S, Hortiwakul T, Silpapojakul K, Siriyasatien P. Consecutive cutaneous and visceral leishmaniasis manifestations involving a novel Leishmania species in two HIV patients in Thailand. Am J Trop Med Hyg 2012; 87:76-80. [PMID: 22764295 DOI: 10.4269/ajtmh.2012.11-0749] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Leishmaniasis is an emerging disease in Thailand. Herein, we report on two human immunodeficiency virus (HIV)-infected patients with leishmaniasis who presented with overlapping manifestations between cutaneous and visceral leishmaniasis. Sequencing analysis of the internal transcribed spacer 1 (ITS1) of the ribosomal RNA gene showed that the species was identical to a new species recently described in Thailand. The detection of DNA of this Leishmania species in saliva may have important implications for transmission and epidemiological studies.
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Affiliation(s)
- Sarunyou Chusri
- Division of Infectious Diseases, Department of Internal Medicine, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand.
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Farahmand M, Nahrevanian H, Shirazi HA, Naeimi S, Farzanehnejad Z. An overview of a diagnostic and epidemiologic reappraisal of cutaneous leishmaniasis in Iran. Braz J Infect Dis 2011. [DOI: 10.1016/s1413-8670(11)70134-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Ampuero J, Rios AP, Carranza-Tamayo CO, Romero GAS. Genus-specific kinetoplast-DNA PCR and parasite culture for the diagnosis of localised cutaneous leishmaniasis: applications for clinical trials under field conditions in Brazil. Mem Inst Oswaldo Cruz 2010; 104:992-7. [PMID: 20027466 DOI: 10.1590/s0074-02762009000700009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Accepted: 09/02/2009] [Indexed: 11/22/2022] Open
Abstract
The positivities of two methods for the diagnosis of localised cutaneous leishmaniasis (CL) were estimated in 280 patients enrolled in a clinical trial. The trial was conducted in an endemic area of Leishmania (Viannia) braziliensis and trial participants were patients with skin ulcers and positive leishmanin skin tests. Patients underwent aspirative skin punctures of the ulcerated lesions and lymph nodes for in vitro cultures, which were processed under field conditions at the local health centre. Skin lesion biopsies were tested at a reference laboratory using kinetoplastid DNA (kDNA)-PCR to detect DNA. The median time required to obtain a positive culture from the skin samples was seven days and the contamination rate of the samples was 1.8%. The positivities of the cultures from skin lesions, kDNA-PCR and the combination of the two methods were 78.2% (95% CI: 73-82.6%), 89.3% (95% CI: 85.1-92.4%) and 97.1% (95% CI: 94.5-98.5%). We conclude that parasite culture is a feasible method for the detection of Leishmania in field conditions and that the combination of culture and PCR has a potential role for the diagnosis of CL in candidates for clinical trials.
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Affiliation(s)
- Julia Ampuero
- Núcleo de Medicina Tropical, Universidade de Brasília, Brasília, DF, Brasil
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Luz ZMP, Silva ARD, Silva FDO, Caligiorne RB, Oliveira E, Rabello A. Lesion aspirate culture for the diagnosis and isolation of Leishmania spp. from patients with cutaneous leishmaniasis. Mem Inst Oswaldo Cruz 2009; 104:62-6. [PMID: 19274378 DOI: 10.1590/s0074-02762009000100010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Accepted: 01/05/2009] [Indexed: 11/22/2022] Open
Abstract
The detection of Leishmania spp. in skin lesion aspirates, using a puncture technique, was evaluated in 76 patients with cutaneous leishmaniasis (CL) who were referred to a Leishmaniasis Reference Centre in Brazil. CL was defined based on skin lesions suggestive of the disease and on a positive result of the Montenegro skin test or Giemsa-stained imprints of biopsy fragments. The aspirates were cultured using a vacuum tube device containing culture medium and evaluated for the presence of Leishmania spp. The biphasic medium culture was examined once a week for three weeks. Promastigotes were observed in 53/76 (69.7%) cultures. Stained smears from 60 of the 76 patients were evaluated using PCR-RFLP to detect the conserved minicircle region of Leishmania spp. and to classify the parasite. Of these patients, 45 (75%) showed positive results in aspirate culture and 15 presented negative results. The PCR was positive in 80% (53/60) samples. The PCR-RFLP profile was determined in 49 samples, of which 45 (92%) showed a pattern compatible with Leishmania (Viannia) braziliensis. The aspirate culture is a sensitive and feasible method for diagnosing CL and may be routinely adopted by health services for L. (V.) braziliensis isolation and identification.
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Affiliation(s)
- Zélia Maria Profeta Luz
- Laboratório de Pesquisas Clínicas, Centro de Referência em Leishmanioses, Instituto René Rachou, Fiocruz, Belo Horizonte, MG, Brasil, 30190-002.
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Romero GAS, Noronha EF, Pirmez C, Pires FDESS, Fernandes O, Nehme NS, Cupolillo E, Firoozmand L, da Graça GC, Volpini A, Santos SL, Romanha AJ. Sensitivity and reproducibility of a PCR assay for Leishmania detection using skin biopsy imprints on filter paper. Acta Trop 2009; 109:74-7. [PMID: 18996076 DOI: 10.1016/j.actatropica.2008.10.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Revised: 10/03/2008] [Accepted: 10/08/2008] [Indexed: 11/17/2022]
Abstract
The sensitivity and reproducibility of a PCR targeted to amplify the conserved 120 base-pair region of minicircles from Leishmania kDNA was defined using DNA extracted from skin biopsy imprints on filter paper. Seventy-seven patients with cutaneous leishmaniasis from an endemic region of Leishmania (Viannia) braziliensis in Brazil underwent skin biopsy of the ulcer border. Tissue samples were imprinted on filter paper and then, they were stored at -20 degrees C. Imprints on filter paper were stored at 4 degrees C. Samples were processed at three laboratories; Lab1 and Lab2 performed the PCR-kDNA assay using DNA extracted from the filter paper, and Lab3 processed PCR-kDNA using DNA from fresh-frozen tissue used as a gold standard. All samples were codified to maintain blinding during lab processing. Fifty-three (68.8%) patients had parasites isolated and identified by isoenzymes as L. (V.) braziliensis. The positivity of PCR-kDNA was similar between the three laboratories: 87.0, 85.7 and 88.3% (Lab1, Lab2 and Lab3, respectively). The sensitivity of PCR-kDNA in culture-proven cases was better, and showed similar results in all laboratories: 95.8, 95.8 and 97.9% (Lab1, Lab2 and Lab3, respectively). Data from the 77 enrolled patients showed an overall percent agreement of 80.5% (Kappa=0.173) for the filter-paper approach between Lab1 and Lab2. Percent agreement between Lab1 and Lab3 was 83.1% (Kappa=0.22), and it was 94.8% between Lab2 and Lab3 (Kappa=0.77). Fifteen patients were diagnosed in just one of the two laboratories that used DNA extracted from filter paper. We conclude that the sensitivity of the filter paper approach is satisfactory and could be used in clinical trials and field work. Reproducibility could be improved using two separate imprints from the same biopsy sample.
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Tojal da Silva AC, Cupolillo E, Volpini AC, Almeida R, Romero GAS. Species diversity causing human cutaneous leishmaniasis in Rio Branco, state of Acre, Brazil. Trop Med Int Health 2006; 11:1388-98. [PMID: 16930261 DOI: 10.1111/j.1365-3156.2006.01695.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Information on Leishmania species diversity in western Brazilian Amazon and the clinical picture of human cutaneous leishmaniasis it causes is scarce. We describe clinical findings, diagnostic procedures and identification of Leishmania species in patients from that region. METHODS The sample consisted of 50 patients, prospectively evaluated for epidemiological and clinical characteristics by means of a structured questionnaire. Conventional and molecular tools were applied to confirm the parasitological diagnosis and identify the species responsible for the disease. RESULTS Patients were predominantly male (76.5%) and living in rural areas. Median average age was 18 years and median average disease evolution was 8 weeks. For the diagnostic procedures of leishmanin skin test, direct visualization of amastigotes in dermal scrapings and parasite culture of aspirates of the ulcer border were positive for 98%, 52% and 34%, respectively. Molecular methods applied to DNA extracted from skin biopsies of the 50 patients yielded 100%, 82% and 44% positivity by PCR minicircle kDNA, PCR-RFLP ITS1rDNA and PCR-glucose-6-phosphate (G6P), respectively. Fourteen samples from 13 patients were successfully isolated and identified. Multilocus enzyme electrophoresis, PCR-RFLP ITS1rDNA and PCR-G6P permitted identification of the Leishmania species responsible for the aetiology of American tegumentary leishmaniasis in 60% of the examined patients: 16 Leishmania (Viannia) braziliensis, 12 Leishmania (Viannia) lainsoni, 1 Leishmania (Viannia) guyanensis and 1 putative hybrid of Leishmania (Viannia) naiffi and L. (V.) lainsoni. CONCLUSION The clinical and epidemiological behaviour of cutaneous leishmaniasis in Acre, Brazil, is similar to other Amazon scenarios previously described; however Acre's complex parasite diversity may be contributed to the concomitant circulation of at least three distinct Leishmania species. The implementation of control interventions in the studied area must take into consideration the possibility of various expected phlebotomine vectors and reservoirs.
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Affiliation(s)
- Anna Christina Tojal da Silva
- Núcleo de Medicina Tropical, Universidade de Brasília, Campus Darcy Ribeiro, Brasília, DF, and Serviço de Imunologia, Hospital Universitário Professor Edgar Santos, Salvador, Brazil
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Romero GAS, Ishikawa E, Cupolillo E, Toaldo CB, Guerra MVDF, Paes MG, Macêdo VDO, Shaw JJ. Identification of antigenically distinct populations of Leishmania (Viannia) guyanensis from Manaus, Brazil, using monoclonal antibodies. Acta Trop 2002; 82:25-9. [PMID: 11904100 DOI: 10.1016/s0001-706x(02)00002-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Eighty Leishmania isolates from patients who contracted cutaneous leishmaniasis in the Manaus region, Amazonas State, Brazil, were identified as Leishmania (Viannia) guyanensis by the electrophoretic profiles of six enzymes. None reacted with the species-specific monoclonal antibody B19. Two L. (V.) guyanensis subpopulations were detected with the monoclonals B2 and B12. The lack of B19 expression by the L. (V.) guyanensis strains in the present study contrasts with that of the vast majority of the strains of the same parasite from eastern Amazonia and French Guyana that express the epitope.
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Affiliation(s)
- Gustavo Adolfo Sierra Romero
- Núcleo de Medicina Tropical, Universidade de Brasília, Campus Universitário, Asa Norte. Caixa Postal 04517, DF, 70919-970, Brasilia, Brazil.
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Romero GAS, Ishikawa E, Cupolillo E, Toaldo CB, Guerra MVF, Paes MG, Macêdo VO, Shaw JJ. The rarity of infection with Leishmania (Viannia) braziliensis among patients from the Manaus region of Amazonas state, Brazil, who have cutaneous leishmaniasis. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2002; 96:131-6. [PMID: 12080973 DOI: 10.1179/000349802125000745] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The frequency of Leishmania ( Viannia) braziliensis infection was assessed in 79 of the 138 patients with cutaneous leishmaniasis who attended a reference outpatient unit in Manaus, Amazonas state, between the August and December of 1997. The disease was characterized by one or more cutaneous ulcers, the skin lesions being frequently associated with satellite lymph-node enlargement. All parasite isolates were identified using monoclonal antibodies and enzyme electrophoresis. Only two (2.8%) of the 71 patients from whom parasites were successfully isolated were found to be infected with L. ( V.) braziliensis, the other 69 isolates being identified, from their isoenzyme profiles, as L. ( V.) guyanensis. In the Manaus region, therefore, almost all human cutaneous leishmaniasis is the result of infection with L. (V.) guyanensis, and L. ( V.) braziliensis is a relatively rare cause of the disease.
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Affiliation(s)
- G A S Romero
- Núcleo de Medicina Tropical, Universidade de Brasília, Asa Norte, Brazil.
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Romero GA, Guerra MV, Paes MG, Cupolillo E, Bentin Toaldo C, Macêdo VO, Fernandes O. Sensitivity of the polymerase chain reaction for the diagnosis of cutaneous leishmaniasis due to Leishmania (Viannia) guyanensis. Acta Trop 2001; 79:225-9. [PMID: 11412806 DOI: 10.1016/s0001-706x(01)00140-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The sensitivity of the polymerase chain reaction (PCR) in 35 consecutive outpatients with cutaneous leishmaniasis caused by Leishmania (Viannia) guyanensis was evaluated using, as gold standard, the in vitro isolation of the parasite through culture of aspirates of the cutaneous ulcers. All isolates were identified using electrophoretic enzyme analysis. Patients were mainly young males with recent onset disease without prior specific treatment. PCR was performed using DNA extracted from fresh frozen biopsies of cutaneous ulcers. The reaction used a pair of oligonucleotides that amplify the conserved region of the minicircle molecule. PCR showed 100% sensitivity (95% CI from 90.0 to 100.0). These results were similar to the visualization of amastigotes in imprint preparations of cutaneous biopsy tissue and the inoculation of biopsy material in golden hamsters. Despite the high sensitivity of the PCR, in this particular clinical setting of cutaneous leishmaniasis caused by L. (V.) guyanensis in the Brazilian Amazon, it appears that the method of choice for diagnosis should be the direct visualization of amastigotes using imprint preparations and the PCR reserved for those patients with negative imprint results.
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Affiliation(s)
- G A Romero
- Núcleo de Medicina Tropical, Universidade de Brasília, Campus Universitário, Asa Norte, P.O. Box 04517, DF. 70919-970, Brasília, Brazil.
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Romero GA, Vinitius De Farias Guerra M, Gomes Paes M, de Oliveira Macêdo V. Comparison of cutaneous leishmaniasis due to Leishmania (Viannia) braziliensis and L. (V.) guyanensis in Brazil: clinical findings and diagnostic approach. Clin Infect Dis 2001; 32:1304-12. [PMID: 11303265 DOI: 10.1086/319990] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2000] [Revised: 09/18/2000] [Indexed: 11/03/2022] Open
Abstract
We compared the clinical findings and diagnostic methods for 66 patients with cutaneous leishmaniasis in the state of Bahia, Brazil, who were infected by Leishmania (Viannia) braziliensis (group A), with those for 68 patients in the state of Amazonas, Brazil, who were mainly infected by Leishmania (Viannia) guyanensis (group B). Differences were observed with regard to number, size, and location of skin lesions and to the pattern of lymphatic involvement. Patients in group B had smaller and more numerous lesions, which were frequently located above the waist, versus the larger but less numerous lesions among patients in group A, which were usually located on the lower limbs. Lymphatic involvement was present in 55 (83.3%) of the 66 patients in group A and in 42 (61.8%) of the 68 patients in group B (P=0.005). The positivity rates of imprints and skin culture procedures were higher in group B. Sensitivity of in vitro culture of skin aspirates was 47.0% and 91.2% for groups A and B, respectively (P<.001). Although hamster inoculation showed similar results in both groups, the interval before development of disease was shorter in group B. Our data provide substantial evidence that indicate that the disease caused by these species differs with regard to clinical presentation and diagnostic approach.
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Affiliation(s)
- G A Romero
- Núcleo de Medicina Tropical, Universidade de Brasília, Brasília, Brasil.
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Abstract
There is an urgent need for a safe, effective, easily administered and cheap treatment for cutaneous leishmaniasis. Unfortunately it remains elusive. There have been a number of contributions during the last year, but none will change present day management. The diagnosis of cutaneous leishmaniasis is established on the basis of a typical lesion, a history of exposure and demonstration of the parasite. Molecular methods, usually based on kinetoplast DNA, are being developed and used increasingly to diagnose and type the infecting organism. Pentavalent antimonials remain the mainstay of treatment.
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Affiliation(s)
- N C Hepburn
- Department of Dermatology, County Hospital, Lincoln, UK.
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