International Postgraduate Research Conference (IPRC)
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Item Assessment of the distribution of Aedes breeding sites at the households of district of Gampaha(Faculty of Graduate Studies, University of Kelaniya Sri Lanka, 2022) Perera, E. H. L.; Hapugoda, M. D.; Viswakula, S.; Gunawardene, Y. I. N. S.; Subasinghe, U.; Fernando, L.; Manamperi, A.Dengue is the most important mosquito-borne viral infection in Sri Lanka at present. Integrated Vector Management (IVM) targeting dengue vector mosquitoes has become the main disease control measure. The objective of this study was to assess the distribution of the Aedes breeding habitats in dengue high and low risk areas in the District of Gampaha where the second highest incidence of dengue reported during last 10 years. Negombo Medical Officer of Health (MOH) area was selected based high incidence of dengue cases reported in the District of Gampaha during last 10 years. A dengue high risk (Kurana East) and low risk (Udayarthoppuwa) Grama Niladhari (GN) divisions with similar geographical situation in the same MOH area were selected as study and control areas respectively. Standard larval surveillance was conducted randomly selected 150 houses in each site for 18 months (April, 2018-October, 2019). In the dengue high risk and low risk areas, the proportions of the larvae of Aedes species to the total larval collection were 34.19% (185/541) and 21.68% (147/678) respectively. High densities of Ae. albopictus larvae were reported in both high [171/185=92.4%)] and low [141/147=95.92%) risk areas. Ae. aegypti was present in low abundance in both areas [High risk-7.56% (14/185) and Low risk- 2.72% (4/147)]. In the high-risk site, breeding sites of the Ae. albopictus larvae were reported as plastic buckets/barrels (55.19 %-154/279), waste plastics (35.15%-98/279), metal tins (3.94%-11/279) and tube wells (2.86%-8/279). In low-risk area, the majority of breeding sites for Ae. albopictus larvae was found in coconut shells (76.14%- 201/264) and plastic waste (21.96%-51/264). In both areas, Ae. aegypti larvae was found in plastic buckets/barrels only. There is a significance difference between the Ae. albopictus breeding places in the dengue high and low risk areas (P=0.024). Although Ae. aegypti is considered as the major vector of dengue, Ae. albopictus was reported as the prominent dengue vector species in the high dengue risk area in the District of Gampaha. Even though, municipal council removes solid waste weekly, a large number of breeding sites are available at both areas. As there is a significant difference between Ae. albopictus breeding sites at the dengue high and low risk areas, it is essential to specifically focus on removal of breeding sites for successful vector control measure.Item Assessment of Real Time Polymerase Chain Reaction (PCR) Assay for the Early Diagnosis of Leptospirosis in Humans(International Postgraduate Research Conference 2019, Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2019) Uduwawala, U.M.H.U.; Manamperi, A.; Gunaratna, G.P.S.; Karunanayake, L.; Chandani, W.L.; Hapugoda, M.Leptospirosis is the most widespread zoonotic disease worldwide having a great impact on health issues in developing countries. It is caused by a pathogenic spirochete of the genus Leptospira where humans become infected through contact with the urine of infected animals. It is often exceptionally under-recognized as the clinical manifestation mimics variety of similar disease conditions that occur in the same environmental and climatologic conditions which accentuate the importance of laboratory diagnosis of leptospirosis. At present, no hospital based facilities are available for acute confirmation of the disease. The existing practice is retrospective confirmation with serological diagnosis. Therefore, the establishment of acute phase diagnosis will help in monitoring the disease, determining when hospital admission is required and reduce case fatalities. The objective of this study was to establish and evaluate a molecular-based assay to provide laboratory confirmation of leptospirosis at the acute phase of the infection (1-5 days of fever). Patients fulfilling clinical criteria stipulated by the accepted case definition were selected for the study and patients who failed to show evidence of sero conversion were considered as true negatives. A real time Polymerase Chain Reaction (PCR) assay with targeting a 203 bp fragment in the secY gene which is conserved among pathogenic serovars of Leptospira was established using a reference DNA sample (L.interrogans serovar Icterohaemorrhagiae strain RGA). Analytical sensitivity and the analytical specificity of the assay were calculated. The accuracy of the real time PCR was determined by a panel of acute blood samples collected from laboratory confirmed leptospirosis patients (n=35) and non-leptospirosis (n=44) patients based on Microscopic Agglutination Test (MAT) and/or IgM immunochromatography. Patients who failed to give positive test results either with MAT or IgM immunochromatography were considered as true negatives. Analytical sensitivity was approximately 314 genome equivalents per reaction and analytical specificity showed no amplification of Leptospira saprophytic sp. and other micro-organisms. The assay could effectively detect Leptospira DNA from clinically diagnosed leptospirosis suspected patients with 60.0% (21/35) diagnostic sensitivity and 77.27% (34/44) diagnostic specificity. This may be attributed to some samples failing laboratory confirmation despite their collection based on clinical suspicion. Therefore, real time PCR established can be used for rapid and definitive diagnosis of leptospirosis during the acute phase of infectionItem Possible Application of Sickling Test in Haemoglobinopathy Screening of Sri Lanka.(19th Conference on Postgraduate Research, International Postgraduate Research Conference 2018, Faculty of Graduate Studies,University of Kelaniya, Sri Lanka, 2018) Darshana, T.; Perera, N.; Manamperi, A.; Premawardhena, A.The national screening programme for thalassaemia in Sri Lanka is currently using Full blood count (FBC) with red cell indices as the technique to identify haemoglobinopathies. This approach is likely to miss sickle haemoglobin (Hb-S) as it is well known that Hb-S is not associated with hypochromic microcytosis. Sickling test is a low cost microscopic screening test which detects sickle cell by its characteristic appearance. Therefore, the present study was undertaken to assess the performance of sickling test in identifying Hb-S among relatively high risk population in Hambantota district. A total of 581 school children (grade 11) were selected randomly from 5 schools in Hambantota district. 2 ml of EDTA blood sample was collected from each participant after obtaining informed assent and consent. Screening panel comprises with sickling test by sodium metabisulphite method, one tube osmotic fragility test, dichlorophenol indophenol test (DCIP), FBC and Zinc protoporphyrin test (ZPP). Haemoglobinphenotyping of each sample was confirmed by capillary electrophoresis technique. Four students out of 581 had sickle trait. Three other types of haemoglobinopathies were detected including β-thalassaemia trait (n=17), haemoglobin D trait (n=2) and haemoglobin E trait (n=1). 8% (n=44) had iron deficiency. All 4 cases with sickle trait were positive for sickling test and all other cases were negative. None of the Hb-S case demonstrated hypochromic microcytosis in FBC.The average time taken for red cells with Hb-S to assume the characteristic sickle shape was 28 minutes and 45 seconds. Sickling test demonstrated 100 % sensitivity and 100 % specificity in identifying sickle trait. Our results indicate depending solely on haemoglobin level and red cell indices is inappropriate since all of the sickle trait individuals would have been missed if sickling test was not done. Hence, the adaptation of sickling test can be recommended along with the Full Blood Count test when screening individuals for haemoglobinopathies in Sri LankaItem The Genetic Origins and Molecular Characterization of Sickle Cell Disease in Sri Lanka.(In: Proceedings of the International Postgraduate Research Conference 2017 (IPRC – 2017), Faculty of Graduate Studies, University of Kelaniya, Sri Lanka., 2017) Darshana, L.G.T.; Manamperi, A.; Premawardhena, A.P.Sickle cell disease (SCD) is globally the commonest monogenic disease. Although the incidence is not as common as in India, it is found in Sri Lanka too. A recent hospital based survey identified around 60 patients in the country but no detailed study of SCD have been done to-date. The genetic origin of Haemoglobin (Hb) S found in Sri Lanka is not yet known.