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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty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 Hantavirus Hemorrhagic Fever with Renal Syndrome (HFRS) - Suspected cases in Sri Lanka; clinical picture and epidemiology from 2013-2021(National Institute of Infectious Diseases, 2022) Muthugala, R.; Dheerasekara, K.; Manamperi, A.; Gunasena, S.; Galagoda, G.Hantavirus; Hemorrhagic fever with renal syndrome (HFRS) is an emerging zoonotic disease in Euro-Asia which is clinically indistinguishable from leptospirosis. A total number of 1032 patients were included in the analysis from March 2013 to March 2021 with the clinical suspicion of HFRS-like illness. Of them, 168 patients were positive for hantavirus IgM antibodies. Thirty-one patients out of 35 patients had given a four-fold rise IgG antibody titre with paired serum confirming the acute hantavirus infections. Detected antibodies showed a diverse pattern, strongly cross-reacting with Seoul, Hantaan and Puumala virus antigens. All the IgM positive patients had no serological evidence of acute dengue or leptospirosis and had classical features of HFRS; fever, thrombocytopenia and renal involvement. More than 90% of patients had a history of rodent exposure 2-3 weeks prior to the onset of the fever. The highest number of positive cases were diagnosed from the Western and North-Central Provinces of Sri Lanka during the paddy harvesting seasons. A significant number of patients had developed severe complications with a high mortality rate. Therefore, hantavirus infection should be considered as a differential diagnosis for leptospirosis-like illness in Sri Lanka.Item Development of recombinant proteins as diagnostic intermediates for chikungunya infection(Sri Lanka Association for the Advancement of Science, 2010) Athapaththu, A.M.M.H.; Khanna, N.; Gunasena, S.; Abeyewickreme, W.; Hapugoda, M.D.Chikungunya is an important disease with explosive outbreaks occurring in many South East Asian countries. As the clinical symptoms associated with chikungunya viral infections are often indistinguishable from those of many other viral, bacterial and parasitic infections confirmation of chikungunya outbreaks is important for clinicians for proper management of patients and for vector control programmers. Laboratory diagnosis of chikungunya in Sri Lanka is hindered by the non-availability of reliable commercial diagnostic kits and inaccessibility to reagents. There is a need to develop an assay that can confirm chikungunya, produced at low cost and easily standardized for the use in field settings. Currently available laboratory diagnostic kits depend on ELISA based on whole viral antigens which cause biohazard risk, high production cost and cross reactivity with other organisms of the same genus/family. Therefore, a diagnostic intermediate using a single recombinant protein antigen to overcome problems associated with whole viral antigen/lysate is important. The objective of this study was to assist laboratory confirmation of outbreaks through developing competencies for a rapid laboratory diagnostic method using recombinant protein antigens for chikungunya infection. We have designed 2 novel recombinant protein antigens based on Envelope domain (E), a critical antigenic region of the major structural protein of chikungunya virus. They were expressed in Escherichia coli separately, and resultant proteins were affinity purified and obtained ~5mg and 10mg respectively and protein of >95% purity per liter of culture. These 2 proteins were evaluated as potential diagnostic intermediates in ELISA separately for the detection of anti-chikungunya Immunoglobulin M (IgM) antibody using a panel of well characterized serum samples. E1 and E2 showed 60% and 67% positivity respectively. Specificity proteins were tested using serum from healthy volunteers and infected with other viral diseases. Two proteins could detect only anti-chikungunya IgM antibodies. We demonstrated that these 2 novel recombinant protein antigens can function as diagnostic intermediates. Acknowledgements: Financial assistance from the International Centre for Genetic Engineering and Biotechnology (ICGEB CRP/ SRI08 02) and International Atomic Energy Agency (IAEA SRI TC 5-042) are gratefully acknowledgedItem Comparison of recombinant protein and cell lysate antigens for detection of anti-chikungunya (CHIK) IgM antibody(University of Kelaniya, 2011) Athapaththu, A.M.M.; Abeyewickreme, W.; Hapugoda, M.; Khanna, N.; Inouve, S.; Tun, M.M.N.; Gunasena, S.Chikungunya (CHIK) virus specific antigen which has high specificity and low cross reactivity with other related diseases is required for laboratory confirmation. The objective of this study is to compare two antigens for detection of anti-CHIK antibody. In this study, two antigens (viral cell lysate and recombinant protein) were evaluated for detection of anti-CHIK antibody by using IgM ELISA. A novel recombinant protein antigen was designed based on envelope domain, a critical antigenic region of the major structural protein. This protein was expressed in Escherichia coli and resultant protein was affinity purified and 10mg with >95% of purity per liter of culture was obtained. Cell lysate antigen was prepared using a crude culture fluid. Two antigens were evaluated separately using a panel of well characterized serum samples obtained from the Dept. of Virology (WHO Reference Centre for Viral Reference and Research), Institute of Tropical Medicine, Nagasaki University. A total of 64 serum samples confirmed as positives and 22 confirmed as negatives were used to evaluate the antigens. Specificity and sensitivity of the recombinant protein antigen was 48% and 90% respectively. Specificity and sensitivity of the viral lysate antigen was 17% and 100% respectively. Viral lysate antigens can cause biohazard risk, high production cost and cross reactivity with other organisms of the same genus/family. Recombinant protein antigen which shows high specificity and sensitivity used in this study is important to overcome problems associated with viral lysate antigen. Testing of a large number of samples is needed to reconfirm this finding. Acknowledgment: Financial assistance and technical co-operation by International Center for Genetic Engineering and Biotechnology (ICGEB CRP SRL 08/02), National Science Foundation (NSF/RG/2009/BT/01) and International Atomic Energy Authority (IAEA/SRL/5/042) is acknowledged.