University of Colombo e-Repository

UCER (University of Colombo Electronic Repository) is a collection of scientific research publications by researchers at the University of Colombo, Sri Lanka. This e-Repository serves to manage, preserve and make available the academic works of the faculty, postgraduate students, and research groups. The collection includes faculty publications, master's and doctoral theses abstracts. This repository is updated regularly, and new works are added to collections on a continuous basis

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Authors are responsible for obtaining copyright permission from the publisher and submitting the signed declaration to ir@lib.cmb.ac.lk.

Recent Submissions

External ophthalmomyiasis by larvae of Oestrus ovis (sheep nasal botfly): Second case report from Sri Lanka
(University of Colombo, 2022) Gunathilake, J.A.M.T.N.; Gunawardena, S; Dayawansa, K.R.; Senanayake, S.A.S.C.; Gunatilake, M.H.; Rajapaksha, G.
Introduction: External ophthalmomyiasis is the invasion of superficial tissues of the eye by fly larvae of the order Diptera. Human ophthalmomyiasis due to Oestrus ovis has been reported worldwide, typically in farmers and shepherds, especially in sheep and goat rearing countries of the Mediterranean basin. It is rare in Sri Lanka, and this is the second case that is being reported. In 2004, the first case was identified in a paddy farmer residing in Puttalam.
Serodiagnosis of Leishmania donovani induced cutaneous leishmaniasis: A method comparison study
(University of Colombo, 2022) Samarakone, A.S.C.; Siriwardana, H.V.Y.D.; Soysa, P.; Ali, N.; Bhattacharyya, A.; Ejazi, S.A.; Deepachandi, B,
Introduction: Sri Lanka reports a large focus of cutaneous leishmaniasis (CL). CL is not known to exert a high humoral response. However, we detected a high seroprevalence for CL in Sri Lanka and developed a cost-effective in-house ELISA assay that has been described previously. This assay is important to detect microscopy negative patients prior to conducting second line investigations and to detect pre-clinical infections in the field. The aim of the current study was to compare the local assay with other known assays. Methods: Study samples (n=100) were collected randomly from patients with laboratory confirmed CL. Control samples (n=25) were collected through field visits to disease endemic and non-endemic areas. In-house ELISA, DAT, Indian dipstick test and rK39 strip test were carried out on all study samples. The specificity and sensitivity were analysed. The cost analysis was also done per patient.
Development and validation of an in-house ELISA to detect Leishmania parasites in dogs
(University of Colombo, 2022) Greniyar, B.K.; Karunaweera, N.D.; Senanayake, S.; Thoradeniya, T.; Dilanthi, H.W.
Introduction: Leishmaniasis, a vector-borne parasitic disease, caused by Leishmania donovani is endemic in Sri Lanka. Inconclusive evidence suggests the possibility of dogs being a reservoir for Leishmania. Identification of animal reservoirs is crucial to control the infection. The objective of this study was to develop and validate a low-cost ELISA method to screen for Leishmania in dogs. Methods: An experimental study was conducted. Leishmania parasites were cultured, and crude protein lysate was extracted and quantified. The ELISA was optimised using checkerboard titration and was validated using a commercial kit. Accuracy, precision, linearity, specificity and sensitivity of the in-house ELISA were determined. The crosstab analysis was performed to determine the sensitivity and specificity of the in-house method. Blood samples were collected from 71 dogs: 60 from Kilinochchi and 11 from Mirigama. The collected serum samples were analysed using the optimised in-house ELISA.
Development of a PCR based assay for the detection of Rigidoporus microporus (causative organism of white root disease of rubber)
(University of Colombo, 2022) Dharmadeva, S.; Fernando, T.H.P.S.; Ediriweera, M.K.; Gunaratna, L.N.R.; Weerasena, O.V.D.S.J.; Siridewa, K.
Introduction: Rigidoporus microporus, one of the most harmful fungal pathogens which cause white root disease, affects Para rubber (Hevea brasiliensis) plantation, the second largest plantation in Sri Lanka. R. Microporus, a member of basidiomycetes division, affects the plants starting from its root to other parts. The damage is caused due to certain enzymes produced by the fungus and this occurs stage by stage. Firstly, a formation of white rhizomorphs grows and firmly adheres to the root’s debris. Next, the collar region of trees gets infected and basidiocarps occur. The primary justification for conducting this study is because the roots of plants are initially affected making it difficult to detect the fungus. Hence initial identification of the fungus is important so that the pathogen can be detected at an early stage which helps to halt the progression of the disease. Accordingly, the objective of the study was to develop a polymerase chain reaction (PCR) based assay for the detection of R. microporus. Methods: R. microporus isolates’ DNA was extracted using two methods and PCR amplification was performed. For PCR amplification, β-tubulin primers were designed using the Bioedit software and Primer3 Input (version 0.4.0). With the chosen primer, temperature, MgCl2 and dNTPs were optimised. Sensitivity and specificity assay was performed using prior PCR conditions.
DNA methylation in methylenetetrahydrofolate reductase (MTHFR) gene promoter and 5-formyl-tetrahydrofolate (5-formyl-THF) levels in folic acid supplemented pregnant women
(University of Colombo, 2022) Weerasinghe, S.A.; Rabindrakumar, M.S.K.; Wijesundera, W.S.S.; Thoradeniya, S.T.
Introduction: DNA methylation is an epigenetic modification critical for gene expression regulation. Folate metabolism cycle is intricately regulated to provide methyl groups for DNA methylation. The genetic and epigenetic influences on folate metabolism and on the levels of different folate forms are yet unclear. Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in folate metabolism that determines the availability of methyl groups. The study aims were to assess the methylation status of MTHFR gene promoter and to investigate the association between DNA methylation status of MTHFR promoter and concentrations of 5-formyl-tetrahydrofolate in folic acid supplemented Sri Lankan pregnant women. Methods: Methylation Specific PCR was used to analyse methylation status of MTHFR promoter (n=20) at two time points: baseline (before FA supplementation) and delivery (after FA supplementation). Available data on 5-formyl-THF levels of these pregnant women were compared with the methylation status. Wilcoxon rank test was performed to compare the change in DNA methylation status at baseline and delivery, while one-way ANOVA was performed to compare the mean change of 5-formyl-THF level from baseline to delivery between groups