Conference Papers
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This collection contains abstracts of conference papers, presented at local and international conferences by the staff of the Faculty of Medicine
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Item In situ immune response to cutaneous leishmaniasis in Sri Lanka(Sri Lanka Medical Association, 2017) Manamperi, N.H.; Oghumu, S.; Pathirana, N.; de Silva, M.V.C.; Abeyewickreme, W.; Satoskar, A.R.; Karunaweera, N.D.INTRODUCTION & OBJECTIVES: Cutaneous leishmaniasis (CL) in Sri Lanka is caused by Leishmania donovani-MON 37, known to cause visceral leishmaniasis elsewhere. Localized immune response may play a role in disease outcome with T helper (Th) 1 response favouring lesion healing and Th2 response leading to disease progression in animal models. This study describes the localized host immune response to CL in Sri Lanka. METHOD: Skin punch biopsies from 58 patients with parasitologically confirmed CL and 25 healthy controls were quantified for cytokine gene expression of Th1 cytokines interferon (IFN)-γ, interleukin (IL)-12A and tumour necrosis factor (TNF)-α and Th2 cytokines, IL-4 and IL-10 by real-time RT-PCR. Relative copy numbers were calculated using the 2-ΔΔCt method. Non-parametric Mann-Whitney U test and the Spearman’s correlation test were used for statistical analysis. RESULTS: Study group consisted of 37 (63.8%) males and 21 (36.2%) females with a mean age of 35.0 years (SD=12.1, range=18-66), mean lesion duration of 6.75 ±9.1 months (range: 1-48) and a mean size of 176.59±185.76 mm2 (range: 12.6–908.3 mm2). Significant up regulation of IFN-γ (p<0.001) and down regulation of IL-4 (p<0.001) were seen in patients compared to healthy controls. Time taken for lesions to heal correlated significantly with in situ expression of IL-4 (Spearman’s r=0.321, p=0.034). CONCLUSION: Immune response to L. donovani induced CL in Sri Lanka tends to follow the typical Th1/Th2 convention with a Th2 biased milieu favouring poor responsiveness to antimony and delayed lesion healing.Item Study on Phlebotomine sand flies in selected areas in Sri Lanka(Sri Lanka College of Microbiologists, 2006) Senanayake, S.A.S.C.; Karunaweera, N.D.; Abeyewickreme, W.Sandflies are the known vectors of disease leishmaniasis. Though there are three clinical entities (viceral, mucocutaneous and cutaneous),^.only cutaneous form of the disease is seen in Sri Lanka. Presence of sandflies belonging to six species has been reported from various parts of the country since 1910. But the first indigenous case of cutaneous leishmaniasis was recorded in 1922. The number of cases rapidly increased during past few years and it is now been considered as an established disease. The causative organism of the disease is the protozoan parasite Leishmania donovani MON37. The vector of the Sri Lankan cutaneous leishmaniasis is still unknown. This study was carried out in two selected areas in Kurunegala and Matara ditricts where considerable number of patients was reported to the Department of Parasitology, Faculty of Medicine, Colombo. The objectives of the study were to identify the prevalent sandfly species in selected areas and establish the potential vector(s). The adult sandflies were collectedTrom four different sites in selected areas. Three different methodologies were used (cattle-baited net traps, CDC light traps, manual collection and mechanical aspirators). Collections were done for 18 months from Sep2004. Collected sandflies were dissected under dissecting microscope and mounted on glass slides. The specimens were examined under both light and phase contrast microscopes. A subset of collected samples were sent to CDC, Atlanta for molecular based identification. Blood fed females were subjected to gut dissection to demonstrate the presence of leishmania parasites within the vector. Real time PCR analysis was carried out with a subset of samples using Leishmania donovani primers. Two species of sandfies were identified in both areas. They were Phlebotomus argentepes and Sergentomiya zeylanica, two species which had been reported previously. P. argentepes is the established vector of visceral leishmaniasis in India and latter is a non human disease transmitter. A total of 3587 sandfies were examined (1756 from Matara and 1731 from Kurunegala) Male to female ratio of the collection was 6:1(3075 males and 522 females). Only 88 ( 5.01%) P. argentepes were found in Matara and rest 1168 (94.99%) were S. zeylanica. How ever, Kurunegala collection resulted with 1549 (89.48%) P. argentepes and 192 S. zeylanica. None of the method use to demonstrate leishmania parasites in sandflies gave positive results. Financial assistants by National Science Foundation for research Grant 2005 /HS/07 is acknowledged.Item Histopathological spectrum in acute and chronic cutaneous leishmaniasis in Sri Lanka(Sri Lanka College of Microbiologists, 2015) Manamperi, N.H.; de Silva, M.V.C.; Fernando, C.; Pathirana, K.P.N.; Abeyewickreme, W.; Karunaweera, N.D.OBJECTIVES: To describe the histological spectrum of acute and chronic cutaneous leishmaniasis. METHOD: Patients from Sri Lanka army were recruited by active and passive case detection methods and punch biopsies were obtained. Skin biopsies of 35 patients with smear positive for Leishmania amastigotes were processed routinely for histopathology, examined at a conference microscope and classified into 4 groups using modified Ridley criteria for Leishmaniasis as: I - parasitized macrophages with variable lymphocytes and plasma cells; II - parasitized macrophages with lymphocytes, plasma cells and ill formed histiocytic granulomata; III -a mixture of macrophages (with or without parasites), lymphocytes, plasma cells and epithelioid granulomata; IV - epithelioid granulomatous response with a few lymphocytes and plasma cells but no amasigotes. Lesions were categorized as acute (<6 months) or chronic (> 6 months). RESULTS: Study group composed of males with a mean age of 32.6 years (range 22-47) and lesion duration of 5.6 months (range 1-24). Twenty nine (82.9%) were also positive by histopathology. Twenty two (62.9%) were acute and 13 (37.1%) chronic. Group I, II, III and IV patterns were seen in 14 (40%), 12 (34.3%), 5 (14.3%) and 4 (11.4%) respectively and 9 (40.9%), 9 (40.9%), 2 (9.1%) and 2 (9.1 %) of acute lesions and 5 (38.5%), 3 (23.1 %), 3 (23.1 %) and 2 (15.4%) of chronic lesions respectively. CONCLUSION: Histology of cutaneous leishmaniasis shows marked inflammatory cell infiltrate with or without granuloma formation. Majority of patients presenting with either acute or chronic cutaneous leishmaniasis belong to histological groups I or II. ACKNOWLEDGEMENTS: Financial assistance from the University Grants Commission, Sri Lanka (UGC/VC/DRIC/PG/2013/KLN/ 03) and University of Kelaniya (RP/03/04/06/01/2014) are acknowledged. An abstract based on similar work was presented at the 128"1 Anniversary International Medical Congress of the Sri Lanka Medical Association, 5th to 8th July 2015.Item Histopathological spectrum in acute and chronic Cutaneous Leishmaniasis in Sri Lanka(Sri lanka Medical Association, 2015) Manamperi, N.H.; Fernando, C.; Pathirana, K.P.N.; Karunaweera, N.D.; Abeyewickreme, W.; de Silva, M.V.C.INTRODUCTION AND OBJECTIVES: Histological spectrum in cutaneous leishmaniasis (CL) is wide and varied. The objective of this study is to describe the histological spectrum of acute and chronic CL. METHOD: Skin biopsies of 35 patients with smear positive for Leishmania amastigotes were processed routinely for histopathology, examined at a conference microscope and classified into 4 groups using modified Ridley criteria for Leishmaniasis as: I- parasitized macrophages with variable lymphocytes and plasma ceils; 1! - parasitized macrophages with lymphocytes, plasma cells and ill formed histiocytic granulomata; 111 - a mixture of macrophages (with or without parasites), lymphocytes, plasma cells and epithelioid granulomata; IV - epithelioid granulomatous response with a few lymphocytes and plasma cells but no amastigotes. Lesions were categorized as acute (< 6 months) or chronic (> 6 months). RESULTS: Study group composed of all males with a mean age of 32.6 years (range 22 - 47) and lesion duration of 5.6 months (range 1-24). Twenty nine (82.9%) were also positive by histopathology. Twenty two (62.9%) were acute and 13 (37.1%) chronic. Group I, II, Ml and IV patterns were seen in 14 (40%), 12 (34.3%), 5 (14.3%) and 4 (11.4%) respectively and 9 (40.9%), 9 (40.9%), 2 (9.1%) and 2 (9.1%) of acute lesions and 5 (38.5%), 3 (23.1%), 3 (23.1%) and 2 (15.4%) of chronic lesions respectively. CONCLUSION: Histology of CL shows marked inflammatory cell infiltrate with or without granuloma formation. Majority of patients presenting with either acute or chronic CL belong to histological groups I or II.Item Clinical features of cutaneous leishmaniasis in Sri Lanka and molecular identification of L. donovani as the cause(Elsevier, 2008) Siriwardana, H.V.Y.D.; Noyes, H.A.; Beeching, N.J.; Wickremasinghe, A.R.; Chance, M.L.; Bates, P.A.; Karunaweera, N.D.BACKGROUND: Cutaneous leishmaniasis (CL) is a newly established disease in Sri Lanka with over 1500 locally acquired cases reported since year 2001. OBJECTIVES: To study the clinical profile, associated risk factors and genetic analysis of the causative parasite of CL in Sri Lanka. METHODOLOGY: Clinical evaluation was carried out on patients who visited the Department of Parasitology, Faculty of Medicine, Colombo for diagnosis using a pre-tested questionnaire. Light microscopy and/or PCR were performed on lesion material to confirm diagnosis. Formol gel test (FGT) was done on all patients. The causative species was identified by sequencing of the partial 6PGDH gene, followed by microsatellite analysis to study the phylogenetic relationships. RESULTS: There were 401 patients (78.9% males, out of which 57.4% were soldiers) with at least 549 lesions. Most infections were acquired in Northern (55.7%) or Southern (39.3%) Sri Lanka. Several lesion types were noted: papules 23.4%, nodules 25.4%, ulcerating nodules 19.6%, ulcers 23.7%, plaques 6.4% and other 1.7%. Nodules with 5–9 months duration had the highest parasite positivity (n = 100, 75.5%). Sporotrichoid spread (n = 44, 11.9%), satellite lesions (n = 35, 8.9%) and lymphatic spread (n = 109, 27.7%) were commonly observed. No patients had visceral features and the FGT was negative in all subjects. Male sex, 20–40 years of age and over 5 hours/day spent outdoors were identified as risk factors, but not household clustering. The causative species was identified as L. donovani, belonging to a distinct genetic group within that complex. CONCLUSIONS: A dermotrophic variant of L. donovani causes cutaneous leishmaniasis in Sri Lanka. The ability of the local Leishmania parasite to visceralize, self heal or develop drug resistance is yet to be determined. In spite of the generally accepted anthroponotic nature of L donovani, in this study favours zoonotic transmission of the local species. Acknowledgements: Mr. RL Ihalamulla, Mr. S Jayasinghe for technical assistance. Financial support for this study was from Sri Lanka National Science Foundation and the Commonwealth Scholarship Association. © 2008 Elsevier Inc.