Conference Papers
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This collection contains abstracts of conference papers, presented at local and international conferences by the staff of the Faculty of Medicine
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Item Early hepatitis is the strongest risk factor for the development of severe dengue infection: A points-based risk-score to predict critical disease in dengue fever(Sri Lanka Medical Association, 2018) Niriella, M.A.; Udeshika, A.K.M.A.; Liyanage, I.K.; de Silva, A.P.; de Silva, H.J.INTRODUCTION AND OBJECTIVES: Some dengue fever (DF) patients develop plasma leakage [critical-phase (CP)], which may progress to multi-organ failure. We attempted to identify early predictors ofCP in DF. METHODS: This was a retrospective, case-record-based study. Clinical, laboratory features in the first three-days (Dl-3) of illness was used to formulate a risk prediction model (RPM). Patients with serologically confirmed DF, admitted to the University Medical Unit, Teaching Hospital, Ragama, from 01.01.2017-30.06.2017 were included. Patients were randomly assigned to training (TD) and validation datasets (VD) of equal size. Stepwise multivariate logistic regression (p<0.05) was used to identify risk factors in TD. Versions of RPM were compared using Akaike criteria and McFadden's adjusted R2. Coefficients from the best RPM were used to derive weighted risk scores. Best RPM was validated in VD using C-statistic. RESULTS: 697 patients were included (mean-age:34.7±16.1 years, females-48.8%, TD=350, VD=346). CP developed inJ27 (32.6%). Mortality was I%. Risk predictors (p<0.05) were: female gender (OR=2.l), diabetes (OR=l.8), vomiting (OR=l.9), platelets60 IU/L (OR=3.3). In multivariate analysis, female gender (score=2), vomiting (score=3), platelets<120,000/mm-3 (score=3) and AST>60 IU/L 3 (score=4) were significant while diabetes was non-significant. Calculated RPM score ranged from 0-12. C-statistic for the TD was 0.78 and VD 0.77 (Hosmer-Lemeshow test: p=0.19 and 0.34 respectively). A cut-off of 5 was selected to maximise sensitivity (0.96), negative predictive value (0.95) with specificity of 0.44. CONCLUSION: This simple risk score seems useful in identifying those at risk ofCP within Dl-3 of the onset ofDF. The early presence of dengue hepatitis was the strongest predictor of CP.Item Evaluation of a rapid whole blood assay for testing dengue patients at point of care(Sri Lanka College of Microbiologists, 2004) Sunil-Chandra, N.P.; Karunasekera, E.W.S.; Somasiri, D.A.D.H.; Samarakoon, S.M.R.M.; Jayawardena, K.A.T.M.; Fernando, W.M.D.; Wijesooriya, W.R.P.L.I.; Garcia, M.INTRODUCTION: Dengue is the most significant mosquito borne viral disease affecting nations from Asia to the Americas. Symptoms associated with dengue infection range in severity. . The presentation of disease is impacted by age, prior exposure to the virus and the infecting strain of virus. The more severe form of the disease (haemorrhagic fever) can lead to mortality are generally associated with Secondary infections. Clinically, the measurement of dengue-specific IgM and elevated IgG, allows for the detection and differentiation of Primary and Secondary dengue infection. This discrimination is particularly important in situations such as outbreaks where the allocation of resources needs to be directed to those at greatest risk. In cities and major regional centers worldwide clinicians have access to traditional serological techniques such as ELISA and HAI that measure IgM and IgG levels. Unfortunately, clinicians in rural and remote areas generally do not have the resources available for this technology. Hence there is high clinical utility in a field diagnostic device which has the ability to rapidly and accurately detect and differentiate dengue infections. OBJECTIVES: To evaluate a novel dengue whole blood assay (PanBio) having the capacity for qualitative detection of both dengue-specific IgM and IgG, and differentiate between primary and secondary dengue with regard to sensitivity and specificity. To meet the demand for testing at the point of care or in the near patient environment, the test was required to have the capacity to detect antibodies in whole blood. DESIGN, SETTING AND METHODS: This assay device was used at the bed site of patients to evaluate its performance. The test is simply performed by adding the specimen to the sample well followed by running buffer to the buffer well, wait 15 minutes and visually reading the results. No additional materials required. 231 hospital inpatients in the Gampaha district of Sri Lanka, using a finger prick drop of blood as the analyte were assessed against PanBio Dengue Capture IgM and IgG ELISA for the period of 6 weeks starting from 10Ih November 2003. The capacity to detect and differentiate presumptive primary and secondary dengue was evaluated. RESULTS: The whole blood dengue cassette was able to detect 151 positive and 80 negative samples where as the ELISA could detect 126 positive samples and 105 negative patients. The detection of IgM and IgG positive samples by the cassette gave a relative sensitivity of 94.5%, specificity of 86% and 87.1% agreement between the assays. The cassette was able to identify 71% of positive samples as primary infections (IgM positive) and 96.7% as secondary infections (IgG positive with or without IgM) compared to ELISA. CONCLUSION: These data indicate that the Whole Blood Dengue Cassette has good utility in the detection of primary and secondary dengue with a very high accuracy in discriminating patients at greatest risk and represents a valuable field based assay to support the clinical evaluation of patients presenting with symptoms suggestive of dengue fever. ACKNOWLEDGEMENTS: PanBio Ltd, Australia for the financial assistance and Directors of Teaching hospital Ragama and Base hospitals of Negombo, Gampaha and Wathupitiwala.Item A comparison of serological diagnostic techniques in Dengue fever(Sri Lanka College of Microbiologists, 2005) Gunasekera, H.A.K.M.; Senanayake, C.P.; Sunil-Chandra, N.P.; Mendis, L.INTRODUCTION: The Dengue Duo IgM and IgG Rapid Strip test (PanBio Pvt. Ltd., Brisbane, Australia) is a commercially available immunochromatographic test. The Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok Thailand, has developed an in-house anti-dengue/anti-JE IgM and IgG reference enzyme-linked immunosorbent assay (ELISA). OBJECTIVE: To compare the usefulness of the AFRIMS ELISA and PanBio Dengue Duo IgM and IgG Rapid Strip test (PanBio Strip test) in the diagnosis of dengue infections. MATERIALS AND METHOD: 93 non-bacterial undifferentiated fever cases and 50 suspected dengue fever cases were screened for dengue and JE virus infections by the AFRIMS ELISA and also by the PanBio Strip test for dengue. All cases positive for dengue antibodies by either test were also tested by the Haemagglutination Inhibition test. RESULTS: Results were considered conclusive when at least 2 or all 3 of the above tests agreed. The AFRIMS ELISA had a sensitivity of 91.7% and specificity of 100% while the PanBio Strip test has a sensitivity of 93.8% and specificity of 96.8% in diagnosing dengue infections. 91.7% primary and 91.4% secondary infections were correctly classified by the AFRIMS ELISA. The PanBio Strip test identified 100% primary infections and 65.7% of secondary infections. CONCLUSIONS: The PanBio Strip test has a sensitivity and specificity comparable to the AFRIMS ELISA in diagnosing dengue infections although it tends to underestimate the number of secondary infections.Item Repeated dengue shock syndrome and "Dengue myocarditis" responding dramatically to a single dose methyl prednisolone(Sri Lanka Medical Association, 2012) Premaratna, R.; Rodrigo, K.M.D.; Anuratha, A.; de Alwis, V.K.D.; Perera, U.D.C.A.; de Silva, H.J.INTRODUCTION: Place of steroids in the management of severe dengue is unclear. A retrospective observational study appeared to show benefit of methylprednisolone (MP) in a highly selected group of patients. CASE REPORT: A 14-year-old schoolboy developed "myocarditis" (4th day) and on the fifth day, he collapsed with Dengue shock syndrome DSS needing rapid resuscitation with intravenous fluid boluses and dextran. He continued to have high fever (39-410C), and pulse rate (PR)>110/min and developed two further episodes of DSS and was resuscitated with further boluses of dextran. As there was no response with temperature 40.20C, PR 160/min, mid-arm systolic BP 70 mmHg, confused, restless, respiratory rate 36/min, dropping capillary 02 saturation, moderate pleural effusions and ascites, urine output <0.2ml/kg/Hr, made it extremely difficult to select the amount and type of fluid for resuscitation. Due to rapid deterioration a single dose of methylprednisolone (MP) (SOOmg in 200ml saline iv over 20 minutes) was administered as a rescue medication. He had deferversence within 30 minutes, became conscious and alert in 1 hour, PR reduced to 96/minute, BP remained stable above 100/80mmHg and urine output increased to 0.8-1.4ml/Kg/Hr. His ECG became normal after 3 hours, and the echo cardiogram in 12 hours (EF-55%). CONCLUSIONS: This patient with dengue developed three episodes of severe haemodynamic compromise within 12 hours while having third space fluid accumulation, "myocardits" and altered level of consciousness making it difficult to institute fluid therapy. A single dose of MP given as rescue measure resulted in a dramatic recovery suggesting a beneficial effect of MP in sever dengue.byItem Predictors of duration and degree of third space fluid accumulation in adult patients with dengue(Sri Lanka Medical Association, 2012) Premaratna, R.; Ragupathy, A.; Miththinda, J.K.N.D.; de Silva, H.J.INTRODUCTION: Fluid leakage is the hallmark of dengue shock syndrome. It is important to identify clinical and biochemical parameters which predict duration and degree of fluid leakage in dengue. METHODS: 102 patients with confirmed dengue were prospectively followed up for clinical, haematological and biochemical parameters, and they were correlated with ultrasonographic evidence of third space fluid accumulation (TSFA). RESULTS: Of the 102 patients (52 males; mean age 28.3 years(SD=11.8), TSFA was detected in 34/95(36%) after hospital admission; 33/95 had pleural effusions which included all except one of 21/95 who had ascites. 72.7% pleural effusions lasted 3 or more days and 52.4% ascites lasted less than 3 days. Duration of pleural effusion showed a significant positive correlation with maximum percentage rises of PCV (r=0.526,p=0.001) and Hb(r=0.525, p=0.001) and negatively correlated with WBC count (r=-0.361, p=0.020) and platelet count (r=-0.585, p=0.000). There was no correlation with any of the other parameters. The mean lowest WBC count of 3005/mm3that was recorded for patients who developed bilateral pleural effusions (n=21) was significantly less (p=0.042) than the mean lowest WBC count of 4091/mm3 that was detected for unilateral effusions(n=12). Duration of ascites was significantly positively correlated with highest AST(r=0.598, p=0.002) and highest ALT(n=0.721, p=.001. CONCLUSIONS: Maximum percentage rise of Hb and PCV, lower WBC and platelet counts seem to be associated TSFA. Among these, lower WBC counts appear to be more predictive of the degree of fluid leakage. Higher ALT and AST levels seem to be useful in predicting the duration of ascites.Item Predicting acute liver failure in dengue infection(Wiley Blackwell Scientific Publications, 2012) Ranawaka, C.K.; Kumarasena, R.S.; Niriella, M.A.; Miththinda, J.K.N.D.; Pathmeswaran, A.; Dassanayake, A.S.; de Silva, A.P.; Premaratna, R.; de Silva, H.J.BACKGROUND AND AIM: Dengue infections (DI) have a diverse clinical spectrum ranging from asymptomatic illness to severe dengue. Unusual manifestations such as encephalitis, myocarditis, and acute liver failure (ALF) are increasingly recognized. Though ALF is less common has a poor prognosis. Aim of this study was to identify possible predictors of ALF in DI. METHOD: Serologically confirmed patients with DI, admitted to university medical unit, Ragama, Sri Lanka from January 2009 to March 2010 were included. Patients were consisted of direct admission as well as referrals with deranged liver functions. Data was obtained from patient records. RESULTS AND DISCUSSION: Out of 240 patients (male : female 57.7%:42.5%; mean age 35.6 years [SD 15.4 years]), 164 had dengue with warning signs, 27 had dengue without warning signs and 49 had severe dengue. 15/49 severe dengue patients had profound shock. Abdominal pain, persistent vomiting (PV), bleeding, hepatomegaly and ascites were present in 125, 92, 39,129 and 28 cases respectively. Elevated AST/ALT, serum bilirubin (SB), alkaline phosphatase (ALP) and gamma glutamyl transpeptide (GGT) were observed in 208, 20, 18 and 60 patients respectively. Of the 240 patients 41 had AST/ALT > 1000 IU/ml and 199 had AST/ALT < 1000 IU/ml. Only 16/41 patients with AST/ALT > 1000 IU/ml developed ALF while none from the AST/ALT < 1000 IU/ml group. Only 4/15 of profound shock had ALF. Patients with AST/ALT > 1000 IU/ml, presence of 2 or 3 of; elevated SB, elevated ALP or PV predicted the development of ALF with 93.8% sensitivity, 98.7% specificity, 83.3% positive predictive value (PPV) and 99% negative predictive value (NPV) with p < 0.001. CONCLUSIONS: Dengue patients who’s AST/ALT < 1000 IU/ml, excluded patients at risk of ALF. Presence of 2 or 3 of: PV, elevated SB or elevated ALP in a patient with AST/ALT > 1000 IU/ml may indicate impending ALF. This needs further validation in a larger populationItem Detection of dengue virus in Aedes albopictus mosquitoes by Reverse Transcription Polymerase-Chain Reaction-Liquid Hybridization (RT-PCR-LH) based assay.(Sri Lanka College of Microbiologists, 2003) Hapugoda, M.D.; Gunasekera, M.B.; de Silva, N.R.; Gunasena, S.; Prithimala, L.D.; Dayanath, M.Y.D.; Abeyewickreme, W.Dengue is an important public health problem. In this study an RT-PCR-LH assay was developed for the detection of dengue virus in Ae.albopictus, a vector of dengue. Laboratory bred Ae.albopictus (adults inoculated with dengue prototypes were tested by RT-PCR-LH assay. RT-PCR products of NS3 gene of 4 dengue prototypes were hybridized in liquid phase with 32P) labelled cocktail of dengue serotype-specific ologonucliotides. Semi-Nested-PCR agarose gel electrophoresis (Semi-Nested-PCR-AGE) assay with dengue type specific oligonucliotides was carried out for typing of RT-PCR products. Wild-caught Ae.albopictus (larvae (n=89 pools) and adults (n=69 pools) collected from dengue case reported stations during the period of 1999-2002 were also tested by RT-PCR-LH and typed by Nested-PCR-AGE assay). A DNA band (470bp) specific for dengue virus was observed in all pools of Ae.albopictus (inoculated with dengue prototypes in RT-PCR-LH assay. When RT-PCR products of dengue prototypes inoculated mosquitoes were typed by Semi-Nested-PCR-AGE assay, bands of 169,362, 265, 426 bp sizes corresponding to DEN1, DEN2, DEN3 and DEN4 respectively were observed. The DNA band specific for dengue virus (470bp) was also observed in 6 pools of wild-caught adults in RT-PCR-LH assay. They were found to be infected with DEN3 (265bp DEN3 specific DNA band was detected) by Semi-Nested-PCR-AGE assay. None of the wild-caught larvae showed dengue specific DNA band (470bp) in RT-PCR-LH assay). RT-PCR-LH with Semi-Nested-PCR-AGE assays are useful for the detection and typing of dengue virus in Ae.albopictus. Ae.albopictus (in Sri Lanka is competent in transmitting DEN3 and possibly other serotypes. Detection of dengue virus for the first time in Ae.albopictus in Sri Lanka confirms earlier observations that it may play an important role in transmitting dengue). Acknowledgements: Financial assistance by the International Atomic Energy Agency (Technical Co¬operation grant no SLR/ 06 / 024) and University of Kelaniya (Research grant no RP/03/04/06/01/00) is gratefully acknowledged.Item Breeding of aedes Aegypti and Aedes albopictus in some dengue endemic areas.(Sri Lanka College of Microbiologists, 2000) Hapugoda, G.P.G.M.D.; de Silva, N.R.; Abeyewickreme, W.Dengue fever (DF)/Dengue haemorrnagic fever (DHF) is now- the most important and rapidly spreading vector borne disease in the world. Since 1956, over 350 000 patients have been hospitalized and nearly 12 000 deaths have been reported. In Sri Lanka the incidence of DF/DHF has increased cyclically since the first outbreak in Sri Lanka during which 26 deaths were reported. Aedes aegypti is classified as the predominant vector of dengue in Sri Lanka. Ae, albopictus is considered as an important vector in the absence of Ae. aegypti. In this study, larval surveillance was carried out in fixed monitoring stations / hot-spots and random monitoring stations. Fixed monitoring stations were selected based on high incidence of DF/DHF recorded since 1996 in Kurunegala district. Ten premises within one fixed monitoring station were checked for mosquito breeding weekly using ovitraps and the average monthly ovitrap index (%) was calculated. During outbreaks larval surveillance was conducted in fifteen random monitoring stations including 66 houses which were selected based on serologically confirmed DPI DHF cases in and around Kurunegala and Ragama. Observations on average monthly ovitrap index (%) in the fixed monitoring stations showed that the highest ovitrap index was in Kurunegala town area, Ovitrap index of Ae. albopictus was higher than of Ae. aegypti all localities in and around Kurunegala throughout the study period. Data obtained from random monitoring-stations in and around Kurunegala and Ragama revealed that only Ae. albopictus larvae were present in seven stations. There were no stations in which only Ae.aegypti larvae were present. House index of Ae. albopictus was 28% whereas it was 10.6% for both species in random monitoring stations. Results suggest that Ae.albopictus may play a major role in transmitting dengue in some localities in Sri Lanka. This investigation received financial support from University of Kelaniya (Research Grant no-97/1-23) and from the IAEA (Technical Corporation Grant no-SRL/06/024).Item Shifting of circulating serotypes in dengue outbreaks during 2009/2010 in Sri lanka(Faculty of Tropical Medicine, Mahidol University, 2010) Manamperi, N.H.; Athapaththu, A.M.M.H.; Premawansa, G.; Wellawaththage, C.; Jayarathna, T. D. S. S.; Abeyewickreme, W.; Hapugoda, M.D.OBJECTIVES: Sri Lanka has experienced explosive outbreaks of dengue infection in 2009 and 2010. It has been identified that DEN- 3 and DEN- 2 were the predominant serotypes with DEN-1 and DEN- 4 circulating at a lower level in previous dengue outbreaks during 2003-2006, Objective of this study was to identify the circulating serotype/s during 2009 - 2010 outbreaks. METHODOLOGY: A prospective study was carried out at North Colombo Teaching Hospital, Sri Lanka during December 2009-August 2010. Clinically suspected dengue patients, with fever less than 5 days were recruited. An interviewer administered questionnaire was filled for each patient, by a Medical Officer. Venous blood samples confirmed for the presence of dengue virus by RT-PCR were typed by Semi-Nested PCR. RESULTS: Out of the 209 patients recruited in the study 80 (38%) were positive for dengue virus by RT-PCR. Of the positives, 43 (54%) were typed and circulation of all 4 serotypes was observed- Of the 43 positives, presence of DEN-1, DEN-2, DEN-3 and DEN-4 serotypes was 34 (79%), 3 (7%), 2 (5%) and 3 (7%) respectively DEN-1 was the predominant serotype in the recent epidemics which was circulating at a low level in previous epidemics. In DEN-1 infected patients, the mean platelet value was 58,588/ rnm3 and the mean PCV value was 41.4%. Associated symptoms such as headache, retro-orbital pain, neck pain and limb pain were present in 94% (32/34), 59% (20/34), 24% (8/34J and 91% (31/34) patients respectively. Bleeding manifestation developed in 47 % (16/34) patients. The mortality rate ranged from 0.7%- 1.0% during the recent outbreaks. Acknowledgement: Financial and technical assistance from the International Centre for Genetic Engineering and Biotechnology (ICGEB CRP/ SRI08-02) and the International Atomic Energy Agency (IAEA SRI 5/042) is gratefully acknowledged.Item Tetravalent dengue specific domain III based chimeric recombinant protein as dengue diagnostic intermediates for the detection of both anti-dengue immunoglobulin M(IGM) and imunoglobulin G(IGG) antibodies in human serum samples.(International Water Management Institute, 2006) Hapugoda, M.D.; Abeyewickreme, W.; Gunasena, S.; Khanna, N.BACKGROUND: Dengue infection is an important mosquito borne viral infection caused by four serotypes of dengue virus with explosive outbreaks occurring in many tropical areas. Laboratory diagnosis of the disease mainly depends on Enzyme-Linked Immunosorbent Assay (ELISA) based on whole viral antigens which cause biohazard risk, high production cost and cross reactivity with other flaviviruses. OBJECTIVES: To produce a recombinant protein antigen to overcome problems associated with whole dengue viral antigen/lysate or recombinant whole envelope protein. STUDY DESIGN: We have designed and expressed a single recombinant tetravalent protein antigen which contains Domain III of envelope protein from all four serotypes of dengue virus, linked with each other through penta glycine linkers. This synthetic gene was expressed in Escherichia coli and protein was purified using a single affinity chromatographic step. We developed Immunoglobulin M (IgM) and Immunoglobulin G (IgG) ELISAs using this novel protein as the capture antigen. The antigen was validated as a diagnostic reagent on serum samples. RESULTS: 30 mg of recombinant protein per litre of culture could be purified. Both ELISAs developed using this novel recombinant protein showed an excellent agreement with a commercially available IgM ELISA (MRL diagnostic) and haernagglutination inhibition assay respectively. Conclusions: Findings of this study suggests that this single dengue specific tetravalent recombinant protein antigen can be used as a diagnostic intermediate for detection of dengue infection.
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