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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty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 Paediatric rotavirus diarrhoea in Sri Lanka: a preliminary report(Sri Lanka College of Paediatricians, 2007) Chandrasena, T.G.A.N.; Rajindrajith, S.; Ahmed, K.; Pathmeswaran, A.; Abeyewickreme, W.; Nakagomi, O.BACKGROUND: Group A rotavirus is the leading cause of acute gastroenteritis in children. Serotypes Gl, G2, G3 and G4 are mainly responsible for human infections. Strain characterization and serotype distribution of rotavirus in a country is an importaa determinant of future vaccine strategy. Information in this regard is scarce in Sri Lanka. OBJECTIVES: To determine the prevalence, severity and molecular epidemiology of rotavirus diarrhoea among children hospitalized with diarrhoea in Sri Lanka. DESIGN, SETTING AND METHOD: A prospective hospital-based study was conducted in the paediatric units of the North Colombo Teaching Hospital from April 2005-February 2006. Stool samples of children admitted with diarrhoea were analyzed for Group A rotavirus antigen by enzyme linked immunosorbent assay (EL1SA) (Rotaclone). Samples positive for rotavirus were characterized electropherotyping (PAGE) and serotyping (reverse transcription-poiymerase chain reaction (RT-PCR)) respectively. Severity of diarrhoea was assessed by the Vesikari severity score. RESULTS: A total of 341 children [204 males mean age 25.7 months (range 1-144)] were studied. Sixty seven (19.6%) had rotavirus diarrhoea. RT-PCR and PAGE were done on 58 rotavirus positive samples. Thirty one were PAGE positive with 6 different electropherotypes. RT-PCR revealed the presence of serotypes Gl, G2, G3, G4 and G9 in 7 (12.1%), 16 (27.6%),2 (3.4%), 2 (3.4%), and 11 (19.0%) samples respectively. Twenty (34.5%) were untypable. Severity score, assessed in 326 patients, revealed a mean score of 13.3 and 11.4 in rotavirus positive and negative patients respectively (p=0.05). Presence frequency and duration of vomiting and duration of diarrhoea were significantly higher in rotavirus diarrhoea (p<0.05). CONCLUSIONS: Rotavirus is an important agent of severe paediatric diarrhoea in Sri Lanka. Molecular analysis indicates genetic diversity among group A rotavirus in Sri Lanka. This study reports for the first time of G9 type rotavirus infection in Sri Lanka.Item Spatial epidemiology and hotspots of Rotavirus In children: an analysis and mapping using Geographic Information System(Sri Lanka College of Paediatricians, 2010) Gunawardena, N.K.; Rajindrajith, S.; Chandrasena, T.G.A.N.; Nishizono, A.; Moji, K.; Ahmed, K.INTRODUCTION: Rotavirus is a leading cause of acute gastroenteritis in Sri Lanka. Studies from the western world have assessed the seasonal variations of this infection and its association with environmental factors such as rainfall and temperature. However, little is known of its seasonal variation and geographical distribution in Sri Lanka. Areliable and updated distribution map of rotavirus infection is essential for target control strategies and policy making processes. Geographical Information. System (GIS) has previously been used to monitor spatial distribution of diseases and their transmission dynamics. For the first time we describe the spatial epidemiological patterns of rotavirus diarrhoea in Sri Lanka. OBJECTIVE: To study the spatial epidemiological distribution of rotaviral infection among children with diarrhoeal diseases admitted to the North Colombo Teaching Hospital, Ragama. DESIGN, SETTING AND METHOD: This study was carried out in two phases. Phase I, a prospective hospital-based study, was conducted in the North Colombo Teaching Hospital from January 2008 to October 2009 to detect the incidence of rotavirus infection in children with diarrhoea. Stool samples were analyzed for Group A rotavirus antigen by enzyme linked immunosorbent assay (EL1SA) (Rotaclone). During Phase II of the study, patients with rotavirus infection were mapped using geographic coordinates obtained from a hand-held GIS receiver (Trimble Juno SB). Rainfall and temperature data for the years 2008 and 2009 in the Gampaha District were obtained from the Department of Meteorology, Sri Lanka and correlated with the spatial distribution data. RESULTS: In 2008 and 2009, 71 (60.6% males) and 99 (63.6% males) had rotavirus infection respectively. Spatial distribution data showed that most rotavirus infections (78%) presenting to the Teaching Hospital, Ragama were coming from a 10 km radius of catchment area. The hot spots were clustered in and around the marshy land areas of the Gampaha District and 67% use water from their own well or from the well of a neighbour. The peak incidence in both years was between May and July which coincided with the highest rainfall to the area. There was no correlation between environmental temperature and rotavirus infection rates. CONCLUSION: Incidence of rotavirus infection is highest in children living around marshy lands and using water from private sources such as a well.Item Rotavirus surveillance at the North Colombo Teaching Hospital, Sri Lanka, 2007-2008(Sri Lanka College of Paediatricians, 2010) Chandrasena, T.G.A.N.; Rajindrajith, S.; Gunawardena, N.K.; Abayawardana, U.A.T.M.; Ranasinghe, S.L.; Nishizono, A.; Moji, K.; Ahmed, K.INTRODUCTION: Rotavirus disease is a common paediatric problem and accounts for severe dehydrating diarrhoea, a large number of hospital admissions and an annually estimated 600,000 deaths across the world. Prospective Rotavirus surveillance was initiated at the North Colombo Teaching Hospital (NCTH), Sri Lanka from April 2005. The serorype distribution in our previous study was; G9P[S] 35.2%, G12P[8] 14.7%, G3P[4] 17.2%, G2P[8/4/6] 14%, GlP[8/4] 6.5% and G4P[8/4] 3.3%. OBJECTIVE: To describe the serotype distribution of rotavirus responsible for hospitalization at the NCTH. DESIGN, SETTING AND METHOD: A prospective hospital-based study was conducted in the paediatric units of the NCTH from November 2007-October 2008. Stool samples of children admitted with diarrhoea were analyzed for Group A rotavirus antigen by enzyme linked immunosorbent assay (ELISA) (Rotaclone). Stool samples positive for rotavirus were characterized by electropherotyping (PAGE) and serotyping (reverse transcription polymasase chain reaction - RT PCR). RESULTS: Group A rotavirus was detected in 78 (33%) of 231 children less than 5 years of age admitted with diarrhoea. G9, Gl, G2, G3 and G non-typable infections were seen in 33(42%), 31 (40%) 7 (9%), 1 (1.3%) and 4 (5%) respectively. A predominance of G9 serotype (84%) was seen during the initial seven months. Dramatic transition of genotypic predominance to Gl (70%) occurred in the latter half of the year. All Gl, G3 and G9 strains assayed for P genotype contained P8 except two mixed G9 infections which were associated with P4 and PS. In contrast to the previous report, all G2 strains identified were associated with P4 and serotypes G12P [8] and G4P [8/4] were not detected. Polyacrylamide-gel-electrophoresis revealed the presence of El, E2, E3, E4 and E5 electropherotypes with a co-dominance of Eland E5 (30.7%). CONCLUSIONS: During the study period a rising trend in prevalence with a fluctuating genotypic distribution was observed at CNTH, Sri Lanka. The diversity of rotavirus serotypes requires a vaccine that confers adequate homotypic and heterorypic protection against these strains.Item Small circular single stranded DNA viral genomes in unexplained cases of human encephalitis, diarrhea, and in untreated sewage(New York, Academic Press, 2015) Phan, T.G.; Mori, D.; Deng, X.; Rajindrajith, S.; Ranawaka, U.; Fan Ng, T.F.; Bucardo-Rivera, F.; Orlandi, P.; Ahmed, K.; Delwart, E.Viruses with small circular ssDNA genomes encoding a replication initiator protein can infect a wide range of eukaryotic organisms ranging from mammals to fungi. The genomes of two such viruses, a cyclovirus (CyCV-SL) and gemycircularvirus (GemyCV-SL) were detected by deep sequencing of the cerebrospinal fluids of Sri Lankan patients with unexplained encephalitis. One and three out of 201 CSF samples (1.5%) from unexplained encephalitis patients tested by PCR were CyCV-SL and GemyCV-SL DNA positive respectively. Nucleotide similarity searches of pre-existing metagenomics datasets revealed closely related genomes in feces from unexplained cases of diarrhea from Nicaragua and Brazil and in untreated sewage from Nepal. Whether the tropism of the cyclovirus and gemycircularvirus reported here include humans or other cellular sources in or on the human body remains to be determined.Item Inaccurate identification of rotavirus genotype G9 as genotype G3 strains due to primer mismatch(BioMed Central, 2012) Mitui, M.T.; Chandrasena, T.G.A.N.; Chan, P.K.S.; Rajindrajith, S.; Nelson, E.A.S.; Leung, T.F.; Nishizono, A.; Ahmed, K.Reverse transcription (RT)-PCR is now the standard method for typing group A rotaviruses (RVA) to monitor the circulating genotypes in a population. Selection of primers that can accurately type the circulating genotypes is crucial in the context of vaccine introduction and correctly interpreting the impact of vaccination on strain distribution. To our knowledge this study is the first report from Asia of misidentification of genotype G9 as G3 due to a primer-template mismatch. We tested two published G-genotype specific primers sets, designed by Gouvea and colleagues (Set A) and Iturriza-Gomara and colleagues (Set B) on RVA from Hong Kong and Sri Lanka. Among 52 rotaviruses typed as G3 by set A primers, 36 (69.2%) were identified as G9 by nucleotide sequencing and set B primers. Moreover, of 300 rotaviruses tested, 28.3% were untypable by set A primers whereas only 12.3% were untypable by set B primers. Our findings reinforce the need to periodically monitor the primers used for RVA genotyping.