Medicine
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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty
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Item Diagnosing Cutaneous leishmaniasis using Fluorescence in Situ Hybridization: the Sri Lankan Perspective(Taylor & Francis, 2019) Kaluarachchi, T.D.J.; Weerasekera, M. M.; McBain, A. J.; Ranasinghe, S.; Wickremasinghe, R.; Yasawardene, S.; Jayanetti, N.; Wickremasinghe, R.Cutaneous leishmaniasis (CL) caused by Leishmania donovani MON-37 is becoming a major public health problem in Sri Lanka, with 100 new cases per month being reported in endemic regions. Diagnosis of CL is challenging for several reasons. Due to relative specificity and rapidity we propose Fluorescence in Situ Hybridization as a diagnostic tool for CL. The objective was to evaluate the potential of Fluorescence in Situ Hybridization as a diagnostic method for Cutaneous leishmaniasis in Sri Lanka. Literature on current laboratory tests used to diagnose Cutaneous leishmaniasis in Sri Lanka and globally was reviewed. Sri Lankan data were reviewed systematically following the PRISMA guidelines. A narrative of the results is presented. There is currently no gold standard diagnostic method for Cutaneous leishmaniasis. Fluorescence in Situ Hybridization has been previously applied to detect dermal pathologies including those involving infectious agents, and its use to detect the Leishmania parasite in human cutaneous lesions reported in small number of studies, generally with limited numbers of subjects. Advantages of FISH has been specificity, cost and ease-of-use compared to the alternatives. Based on the available literature and our current work, FISH has potential for diagnosing CL and should now be evaluated in larger cohorts in endemic regions. FISH for CL diagnosis could find application in countries such as Sri Lanka, where laboratory facilities may be limited in rural areas where the disease burden is highest.Item Efficacy of a new rapid diagnostic test kit to diagnose Sri Lankan cutaneous leishmaniasis caused by Leishmania donovani(Public Library of Science, 2017) de Silva, G.; Somaratne, V.; Senaratne, S.; Vipuladasa, M.; Wickremasinghe, R.; Wickremasinghe, R.; Ranasinghe, S.BACKGROUND: Cutaneous leishmaniasis (CL) in Sri Lanka is caused by Leishmania donovani. This study assessed the diagnostic value of a new rapid diagnostic immunochromatographic strip (CL-Detect™ IC-RDT), that captures the peroxidoxin antigen of Leishmania amastigotes. METHODOLOGY/PRINCIPAL FINDINGS: We sampled 74 clinically suspected CL lesions, of which 59 (79.7%) were positive by PCR, 43 (58.1%) by Giemsa stained slit skin smear (SSS) and 21 (28.4%) by the new IC-RDT. All samples which were positive either by SSS or IC-RDT or both were positive by PCR. The sensitivities of the IC-RDT and SSS compared to PCR were 36% and 73%, respectively. Fifteen patients from this endemic region were negative by all three tests. Twenty two clinically non-CL skin lesions from a CL non-endemic region were also negative by all three methods. Specificity and PPV of both IC-RDT and SSS compared to PCR were 100%; the NPVs of IC-RDT and SSS were 37% and 58%, respectively. The median parasite grading of the 59 PCR positive samples was 2+ (1-10 parasites/100 HPFs) and IC-RDT positive lesions was 3+ (1-10 parasites /10HPFs). The duration of the lesion was not associated with IC-RDT positivity. CONCLUSIONS/SIGNIFICANCE: The median parasite grade of Sri Lankan CL lesions is low. The low sensitivities of SSS and CL Detect™ IC-RDT may be due to low parasite counts or low expression of peroxidoxin antigen in amastigotes of the Sri Lankan L. donovani strain. Our results indicate that negative SSS has to be combined with PCR for confirmation of CL in Sri Lanka. The current commercially available IC-RDT is not suitable to diagnose CL in Sri Lanka; an IC-RDT with improved sensitivity to detect L. donovani would be a valuable addition in the diagnostic tool kit for Sri Lanka.