Medicine

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    The use of recombinant K39, KMP11, and crude antigen-based indirect ELISA as a serological diagnostic tool and a measure of exposure for cutaneous leishmaniasis in Sri Lanka
    (Springer International, 2024) Karunathilake, C.; Alles, N.; Dewasurendra, R.; Weerasinghe, I.; Chandrasiri, N.; Piyasiri, S.B.; Samaranayake, N.; Silva, H.; Manamperi, N.; Karunaweera, N.
    Cutaneous leishmaniasis (CL) in Sri Lanka is caused by Leishmania donovani, a parasite widely known to cause visceral leishmaniasis. Despite the fact that CL is not generally believed to elicit serological immune responses, recent studies show the presence of antibody responses against this atypical form of CL. This study assesses the potential of using recombinant K39 (rK39), KMP11, and crude parasite antigen-based indirect ELISAs as serological diagnostic tools and measures of exposure for CL in Sri Lanka. The study used serum samples from confirmed CL patients (n = 266) and apparently healthy individuals from endemic settings (n = 411). Serum samples from individuals residing in non-endemic areas were used as negative controls. In-house indirect ELISAs were optimized and validated for recombinant antigens. Previously validated crude parasite extract-based indirect ELISA was performed for comparison. The statistical analyses were performed using SPSS v26.0. The rK39 (sensitivity = 71.2%, specificity = 64%) and KMP11 (sensitivity = 79.2%, specificity = 71.4%) based indirect ELISA were shown to be less suitable for the diagnosis of CL, while crude parasite extract-based indirect ELISA (sensitivity = 82.4%, specificity = 85.7%) might be a better method of diagnosis. All 03 ELISAs seemed to be good methods as measures of exposure since correlations were observed between the seropositivity of all 03 ELISAs (rK39: p = 0.037, KMP11: p = 0.007, CrudeAg: p = 0.000) with provincial case incidences. The findings will be important in identifying the disease hotspots in order to design the control measures for CL induced by L. donovani in Sri Lanka.
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    Prevalence of cutaneous leishmaniasis infection and clinico-epidemiological patterns among military personnel in Mullaitivu and Kilinochchi districts of the Northern Province, early war-torn areas in Sri Lanka.
    (BioMed Central, 2020) Gunathilaka, N.; Semege, S.; Pathirana, N.; Manamperi, N.; Udayanga, L.; Wijesinghe, H.; Premaratne, P.; Fernando, D.
    BACKGROUND: The 30-year-old armed conflict in Sri Lanka resulted in a general breakdown of civil administration in the Northern and Eastern provinces, leading to mobilisation of many armed forces personnel to assist with reconstruction and resettlement. This occupational group has been identified as a priority risk group for leishmaniasis. METHODS: Individuals enlisted at all military establishments in Mullaitivu and Kilinochchi districts, Northern Province of Sri Lanka were included. Five thousand individuals were screened for skin lesions between September 2018 and August 2019. Persons with lesions suspected as cutaneous leishmaniasis (CL) were further investigated. Information on sociodemographic/other potential risk factors was obtained through an interviewer-administered structured questionnaire. The diagnosis was confirmed by microscopic visualization of parasitic stages from different samples obtained (skin scraping, lesion aspirate and tissue impression smears), histopathology and polymerase chain reaction DNA amplification. RESULTS: Among 5000 individuals screened, 74 individuals were suspected of having CL. Of these, 67.6% (n = 50) patients were confirmed for CL by microscopy. Around two third of both males (67.6%; n = 48) and females (66.6%; n = 2) were positive for Leishmania. The soldiers belonging to 26-35-year age group reported the highest susceptibility (83.3%; OR: 4.83, 95% CI: 3.49-6.20%). Of the sociodemographic factors, age, wearing short-sleeved upper body clothing as the uniform and non-use of insect repellents were identified as significant risk factors. Most of the CL patients had a single lesion (86.0%; n = 43) of an ulcerative type (34.0%; n = 17), mostly on their upper limb (67.9%; n = 34). Lesions were mostly 5-10 mm diameter (59.9%; n = 30) in size with poorly defined margins (72.0%; n = 36). Amongst the diagnostic techniques, microscopic examination of slit skin smear and tissue impression smear were able to discriminate the majority of patients (92.1%; n = 46) for CL. CONCLUSIONS: In order to highlight the true burden of leishmaniasis in the military personnel, cases of leishmaniasis from military institutes should be recognized as a different entity per say and be included in the national figures so as to depict the real magnitude of the disease burden amongst this high-risk group. KEYWORDS: Clinical; Cutaneous leishmaniasis; Epidemiological; War-torn areas.
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    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.
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