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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty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 Comparison of different RNA extraction methods for Dengue Reverse Transcription -Polymerase Chain Reaction (RT-PCR)(Sri Lanka Association for the Advancement of Science, 2011) Adihetty, D.D.; Wellawaththage, C.; Abeyewickreme, W.; Abeywickrema, K.; Hapugoda, M.D.Item Correlation of clinical presentation and laboratory confirmation of dengue patients(Sri Lanka Association for the Advancement of Science, 2010) Manamperi, N.H.; Athapaththu, A.M.M.H.; Premawansa, V.; Wellawaththage, C.; Jayarathna, T.D.S.S.; Abeyewickreme, W.; Hapugoda, M.D.Dengue is one of the most important arthropod-borne diseases in the world and it has become a very important disease in Sri Lanka, today. In Sri Lanka, diagnosis of dengue depends mainly on clinical signs and symptoms. Only a few suspected patients are confirmed by laboratory assays based on aetiological agents. The objective of this study was to determine the correlation between clinical presentation and laboratory confirmation of dengue patients. Acute serum samples (n=100) collected from patients clinically suspected of having dengue fever ("'ª-"ý¦> 5 days) warded at the North Colombo Teaching Hospital, Ragama were used for the present study. Serum samples were collected after obtaining informed written consent frompatients and samples were tested by RT-PCR which has high sensitivity (10 FFU/reaction) and specificity. Final diagnosis as dengue or non-dengue was assigned based on the results of RT-PCR assay. Differences in clinical and laboratory data were analyzed in dengue and non dengue patients. Chi-square test was used for comparison of data. The proportion of laboratory confirmed dengue patients were 56% (56/100). Mean platelet count and PCV in laboratory confirmed dengue patients were 60 269/mm 3 (range 3000-306000) and 41% (range 27-61%) and in non dengue patients were 106 318/mm 3 (range 5000-290000) and 41.6% (range 29-53%). Based on WHO criteria for diagnosis of dengue, heada (48/56 vs 41/44, ÝÖ 2 =0.7, p=0.38), retro-orbital pain (30/56 vs 14/44, ÝÖ 2 =3.8, p=0.04), limb pain (51/56 vs 30/44, ÝÖ 2 =7, p=0.00) and external bleeding (29/56 vs 4/44, ÝÖ 2 =18, p=0.00) showed significant association with dengue. Neck pain (10/56 vs 09/44, ÝÖ 2 =0.01, p=0.94), and lymphadenopathy (3/56 vs 02/44, ÝÖ 2 =0.08, p=0.78) did not show significant association with dengue. The infection was confirmed as dengue fever in 11% (6/56) and dengue hemorrhagic fever in 89% (50/56) based on WHO criteria. Surveillance based on clinical diagnosis may result in over estimation of the disease as clinical diagnosis is not specific enough. Laboratory confirmation of dengue suspected patients is important to measure the real incidence of the disease which leads implementation of control measures. Further, thisis important for efficient management of patients.Acknowledgements: Financial and technical assistance from the International Centre for Genetic Engineering and Biotechnology (ICGEB CRP/ SRI08-02) and International Atomic Energy Agency (IAEA SRI 5/042)Item Application of nucleic acid technology (NAT) in the diagnosis of active viral replication in HBV and HCV infections and evidence for HBV surface antigen mutants(Sri Lanka Association for the Advancement of Science, 2008) Manamperi, A.; Gunawardene, Y.I.N.S.; Hapuarachchi, C.; Bandara, A.; Wellawaththage, C.; Abeyewickreme, W.; de Silva, J.Introduction: The community prevalence of Hepatitis B (HBV) and hepatitis C (HCV) infections, although considered low (< 1%) in Sri Lanka based on serological markers, pose a significant health threat to patients in high risk groups. The early diagnosis of active viral infection is crucial in such situations to prevent further transmission and to enable the clinicians to initiate successful therapeutic interventions. Objective: This study was carried out to investigate the usefulness of polymerase chain reaction (PCR) in the diagnosis of active viral replication in HBV and HCV infections. Methodology: All specimens from patients with serological evidence of hepatitis B (HBV surface antigen and/or antibodies for HBV core protein) or hepatitis C (antibodies for hepatitis C core protein-Anti-HCV) and referred to the Molecular Medicine Unit from May 2005 to May 2008 were analyzed by PCR and reverse-transcription PCR (RT-PCR) for HBV DNA (n=130) and HCV RNA (n=95) respectively. Results: Of the 130 patients tested, 57 (44%) were positive for HBV DNA. The positive group of patients included 10 renal transplant patients, 4 multiply transfused patients, 4 paediatric patients with lymphoma, and 1 patient with cirrhosis. Six HBV DNA positive patients had negative HBsAg serology profiles indicating the possibility of surface antigen mutant strains. The HBV DNA negative patients with positive serology profiles indicate sero-converted/ patients with resolved infections or false positive serology results. Of the 95 patients tested, 14 (15%) were positive for HCV RNA and included 3 paediatric patients with thalassaemia. HCV RNA negative, anti-HCV positive profiles reflect either false positive serology results (due to less specific antibody assays) or donors who have been exposed to HCV previously and subsequently resolved their infections. Conclusions: A major proportion of patients with serological markers for HBV have active viral infection whereas only relatively a minor proportion of patients with serological markers for HCV have active viral replication. We have also found the first possible evidence of hepatitis B surface antigen mutant strains. This underlines the importance of the nucleic acid based technology in the diagnosis and assessment of infection with or suspected to have hepatitis B or C infections. We also emphasize the importance of introducing NAT for screening donors for HBV DNA and HCV RNA to substantially lower the risk of acquiring HBV/HCV infection from a transfusion.Item Molecular Diagnosis for confirmation of Infectious Diseases in Sri Lanka in 2009(Sri Lanka Association for the Advancement of Science, 2009) Hapugoda, M.D.; Bandara, K.B.A.T.; Dayanath, M.Y.D.; Wellawaththage, C.; Hapuarachchi, H.A.C.; Abeyewickreme, W.Confirmation of infectious disease outbreaks in Sri Lanka is an important national requirement. Many clinicians as well as general practitioners find it difficult to confirm diagnosis of some infectious diseases only on clinical grounds. Molecular assays can rapidly confirm diagnosis at the early phase of diseases when aetiological agents are present and before antibody titers are at detectable levels. PCR-based assays are more sensitive and more specific than all conventional methods. Overall objective of this study was early, rapid and definitive laboratory confirmation of the aetiology of chikungunya, dengue, Japanese Encephalitis (JE), leishmaniasis, leptospirosis, malaria and West Nile Virus (WNV) through molecular assays. A rapid mobile investigation team equipped with the case definition, questionnaires, sample collection methods and diagnostic methods for each disease was established. This group visited outbreak areas and collected clinical and laboratory information and clinical samples from suspected patients at the early stage of symptoms: 1-5 days. Clinical samples were laboratory tested by disease specific molecular assays (PCR/RT-PCR). Clinical parameters of each disease were analyzed. Only chikungunya, dengue and leptospirosis outbreaks out of the above mentioned diseases were reported during the preceding six months in 2009. The team collected blood samples from clinically suspected cases of chikungunya (n=430), dengue (n=116) and leptospirosis (n=23) from different parts of the island. Molecular assays confirmed infections only in 81% (350/430) for chikungunya, 7% (8/116) for dengue and 9% (2/23) for leptospirosis in selected suspected patients. Reports of the confirmation of the disease outbreak by molecular assay were sent to the relevant health authority within two days to highlight the magnitude of the infection. These results showed importance of aetiological confirmation of infectious diseases by molecular assays. In conclusion, molecular diagnosis using a single clinical sample is important for rapid, definitive and early confirmation of aetiology of a particular infectious disease outbreak when serological methods are of little value at the early stage of infection. This is important for cost effective and efficient control of the outbreaks through proper clinical management.