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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty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 ELISA based evaluation of antibody response to Leishmania in a region endemic for cutaneous leishmaniasis(Oxford, 2022) Piyasiri, S.B.; Samaranayake, T.N.; Silva, H.; Manamperi, N.H.; Karunaweera, N.D.Aims: Leishmaniasis includes several clinical forms. While routine diagnosis of cutaneous leishmaniasis (CL) is by microscopy, an antibody response to CL has been reported in several recent studies. This study evaluated anti-leishmanial IgG antibody responses as a biomarker of active leishmaniasis and a measure of exposure to Leishmania. Methods and results: Sera from 50 untreated CL patients, 140 patients under treatment and 280 healthy individuals residing in endemic regions collected as part of an epidemiological survey, was analysed with an ELISA established in-house using receiver-operator-characteristic (ROC) curve at optimised cut-off value. The assay showed high performance as a diagnostic tool in identifying exposure in endemic individuals (sensitivity: 98%, specificity: 90.3%). All patients showed lower antibody levels over time since onset of lesion/s. Antibody levels were higher (p ˂ 0.01) and persisted for a longer period in untreated patients. In patients under treatment, the level of anti-IgG antibodies was negatively correlated with the total duration the patient had been on treatment. Conclusion: The anti-leishmanial IgG response in L. donovani induced CL is transient and is unlikely to confer protective immunity. Optimised serological assays may be useful in endemic settings for diagnosis and monitoring the treatment response in CL.Item Spatiotemporal distribution of cutaneous leishmaniasis in Sri Lanka and future case burden estimates(Public Library of Science, 2021) Karunaweera, N.D.; Senanayake, S.; Ginige, S.; Silva, H.; Manamperi, N.; Samaranayake, N.; Dewasurendra, R.; Karunanayake, P.; Gamage, D.; de Silva, N.; Senarath, U.; Zhou, G.BACKGROUND: Leishmaniasis is a neglected tropical vector-borne disease, which is on the rise in Sri Lanka. Spatiotemporal and risk factor analyses are useful for understanding transmission dynamics, spatial clustering and predicting future disease distribution and trends to facilitate effective infection control. METHODS: The nationwide clinically confirmed cutaneous leishmaniasis and climatic data were collected from 2001 to 2019. Hierarchical clustering and spatiotemporal cross-correlation analysis were used to measure the region-wide and local (between neighboring districts) synchrony of transmission. A mixed spatiotemporal regression-autoregression model was built to study the effects of climatic, neighboring-district dispersal, and infection carryover variables on leishmaniasis dynamics and spatial distribution. Same model without climatic variables was used to predict the future distribution and trends of leishmaniasis cases in Sri Lanka. RESULTS: A total of 19,361 clinically confirmed leishmaniasis cases have been reported in Sri Lanka from 2001-2019. There were three phases identified: low-transmission phase (2001-2010), parasite population buildup phase (2011-2017), and outbreak phase (2018-2019). Spatially, the districts were divided into three groups based on similarity in temporal dynamics. The global mean correlation among district incidence dynamics was 0.30 (95% CI 0.25-0.35), and the localized mean correlation between neighboring districts was 0.58 (95% CI 0.42-0.73). Risk analysis for the seven districts with the highest incidence rates indicated that precipitation, neighboring-district effect, and infection carryover effect exhibited significant correlation with district-level incidence dynamics. Model-predicted incidence dynamics and case distribution matched well with observed results, except for the outbreak in 2018. The model-predicted 2020 case number is about 5,400 cases, with intensified transmission and expansion of high-transmission area. The predicted case number will be 9115 in 2022 and 19212 in 2025. CONCLUSIONS: The drastic upsurge in leishmaniasis cases in Sri Lanka in the last few year was unprecedented and it was strongly linked to precipitation, high burden of localized infections and inter-district dispersal. Targeted interventions are urgently needed to arrest an uncontrollable disease spread.Item Tissue impression smears as a supplementary diagnostic method for histopathology in cutaneous leishmaniasis in Sri Lanka(American Society of Tropical Medicine and Hygiene, 2018) Manamperi, N.H.; de Silva, M.V.C.; Pathirana, N.; Abeyewickreme, W.; Karunaweera, N.D.Cutaneous leishmaniasis (CL) is diagnosed mainly by light microscopy of smears made using lesion material. Histopathology is usually done in atypical presentations or when lesion smears are negative. Tissue impression smears (TIS) made from skin biopsy specimens were compared with histopathology for the diagnosis of CL. Out of the 111 patients included, 83 (74.8%) were positive by either methods. The TIS was positive in 70.3% whereas histopathology was positive in 56.8% of patients. Tissue impression smears can be used as a supplementary diagnostic test that gives sensitive and rapid results when tissue biopsies are used as the source of lesion material for diagnosis of CL.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 Pathogenesis of Leishmania donovani induced cutaneous leishmaniasis: role of Tumor Necrosis Factor α(Faculty of Medicine, University of Kelaniya, Sri Lanka, 2016) Manamperi, N.H.; Oghumu, S.; Pathirana, K.P.N.; Munidasa, U.A.D.D.; Somaratne, K.K.V.N.; Rathnayake, R.M.D.I.; Thilakaratne, S.M.; de Silva, M.V.C.; Pathmeswaran, A.; Abeyewickreme, W.; Satoskar, A.R.; Karunaweera, N.D.BACKGROUND: Cutaneous leishmaniasis (CL) in Sri Lanka is caused by the usually visceralizing Leishmania donovani. Host immune response plays a key role in the clinical presentation of leishmaniasis. Role of cytokines in pathogenesis of local lesions has not been studied. OBJECTIVE: To describe tissue cytokine expression with lesion progression with time in CL due to Leishmania donovani. METHODS: Skin biopsies from fifty eight patients with parasitologically or histopathologically confirmed CL and 30 healthy controls were analyzed for local tissue expression of Interleukin (IL)-12A, IL-4, IL-10, Interferon-gamma (IFNg) and Tumor Necrosis Factor-alpha (TNF-α). Cytokine mRNA was quantified by real-time RT- PCR using SYBR green. Relative copy numbers were calculated for each gene by 2-ΔΔCt method using β-actin as the reference gene and healthy controls as the calibrator. Spearman correlation was used to determine the correlation between cytokines and duration of active skin lesions. RESULTS: The study group consisted of 37 males (63.8%) and 21 females (36.2%) with a mean age of 35 (SD=12.05) years which ranged between 18-66 years. Mean duration of lesions was 6.8 (SD=9.10) months with a range of 1-48 months. The Spearman correlation coefficient for relative copy numbers and lesion duration was 0.220, 0.077, 0.073, 0.235 and 0.295 for IL-12A, IL-4, IL-10, IFNg and TNF-α respectively. There was a significant positive correlation between expression of TNF-α and lesion duration (p= 0.024). CONCLUSIONS: Localized expression of TNF-α increases with time in CL due to L. donovani in Sri Lanka, which indicates development of a pro-inflammatory immune response at the site of infection as the disease progresses.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.Item Impact of vitamin A supplementation on health status and absenteeism of school children in Sri Lanka(HEC Press, Australia, 2007) Mahawithanage, S.T.C.; Kannangara, K.K.; Wickremasinghe, R.; Chandrika, U.G.; Jansz, E.R.; Karunaweera, N.D.; Wickremasinghe, A.R.The objective of this study was to determine the impact of Vitamin A supplementation on health status and absenteeism of school children. A randomized double blind placebo controlled trial over a period of 13 months was conducted in a rural area of Sri Lanka involving 613 school children attending Grades 1-5 (aged 5 to 13 years). Children were assigned to either 200,000 IU of Vitamin A (n=297) or placebo (n=316) once every 4 months. Socio-demographic data were obtained at baseline, and anthropometry and haemoglobin concentrations were assessed at baseline and post intervention. Serum vitamin A concentrations were assayed by HPLC in a subgroup of children (n=193) before administration of each dose. School absenteeism was recorded. The two groups of children were similar at baseline in all variables. The subgroup of children was comparable to the main study population. The prevalence of vitamin A deficiency (< 20 microg/dL) in the subgroup of children was 8.2%. Changes in anthropometric indices and haemoglobin concentrations were similar in the two groups. The major causes for absenteeism were non-health causes and supplemented children lost a fewer number of school days due to illness than placebo children (p=0.053). Vitamin A concentrations improved with each dose and the improvement was greater with better compliance. Vitamin A supplementation with 200,000 IU every 4 months over 13 months improved vitamin A status and school attendance but not anthropometric status of these children.