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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty

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Dengue fever with bleeding manifestations in pregnancy: our experience
(Sri Lanka College of Obstetricians and Gynaecologists, 2004) de Silva, B.A.; Palihawadana, T.S.; Fernando, W.S.; Wijesinghe, P.S.
Dengue fever, a mosquito borne flavivirus infection is endemic in Sri Lanka. An increased number of cases are seen in the recent past. An increase in the number of patients with secondary infection who are prone to develop complications such as bleeding manifestations, are expected due to repeated outbreaks of the disease, We report four cases of serologically confirmed Dengue fever. Different management strategies were adopted in each patient according to the clinical circumstances. Three antenatal mothers presented in 33, 38 and 39 weeks of POA and bleeding manifestations were present in all three of them. One of them died of an intracerebral haemorrhage after Caesarean section to deliver a stillborn following intrauterine death. Post Partum Haemorrhage (PPH) was experienced in another mother following caesarean section. In one patient bleeding manifestation appeared 2 days following normal delivery. She was managed conservatively. Though the clinical presentations may be similar to that of non pregnant patients, there can be many pitfalls in diagnosis and management of dengue fever occurring in pregnancy. Two of the patients described above developed acute dengue viral hepatitis, which needs to be differentiated from HELLP syndrome and acute fatty liver of pregnancy. Serological tests have a special place in diagnosis than in the non pregnant patients. The classical criteria used to identify Dengue Haemorrhagic fever (DHF), such as an increased haemotocrit and postural hypotension were not present in these patients. In management, the administration of intravenous fluids needed to be more closely observed. They seemed to be more prone to develop bleeding manifestations than non pregnant patients and therefore platelet transfusions were required in early stages. Early interventions to deliver the baby, if the other circumstances permit, seem to offer a better outcome in patients presenting in the antenatal period.
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.
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.
Role of Aedes albopictus in transmitting dengue virus in some endemic areas in Kurunegala District.
(University of Kelaniya, 2003) Hapugoda, M.D.; de Silva, N.R.; Abeysundara, S.; Bandara, K.B.A.T.; Dayanath, M.Y.D.; Abeyewickreme, W.
Abstract Available
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.
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).
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.
Dengue vector surveillance in a dengue hot-spot in Sri Lanka
(Faculty of Tropical Medicine, Mahidol University, 2007) Sumanadasa, S.D.M.; Hapugoda, M.D.; Perera, D.; Bandara, S.; Mansoor, M.A.; Peris, I.; Abeyewickreme, W.
BACKGROUND: In South Asia, dengue has been declared as one of the most, fast-spreading vector-borne diseases. Therefore, mosquito surveillance is important for early detection of outbreaks along with implementation of prompt control activities. OBJECTIVES: To identify entomological risk factors with regard to transmission of dengue in a dengue hot-spot. Seventy five human dwellings in Vehara in the Kurunegala District of the Western Province were selected based on high disease incidence during 2000-2004, high Aedes as well as human population density and increased building activities. Entomological surveillance was done during May-August, 2007. RESULTS: The house Index ranged from 2.67% to 5.33% for Aedes aegypti while it for Aedes albopictus was 1.33% to 6.60%. The container index ranged from 23.67% to 29.33% for Ae. aegypti and from 1.33% to 18% for Ae. aibopictus. Man biting rates of 0.43-5.78 bites/man/hour were estimated for Ae, aegypti, while it ranged between 0.49 and 1.33 for Ae. aibopictus. The most common breeding place for Aedes species was plastic baskets (16%, n=12). DISCUSSIONS: Vector surveillance showed that the predominant vector species present in the study area was Ae. ageypti. Aedes mosquito larval densities and adult biting rates were sufficient to promote outbreaks of dengue in this study area. Community must be educated regarding effective measures to protect them from dengue. Their cooperation should be elicited in the early detection and elimination of vector species by source reduction, environmental management and personal protection measures.
Correlation between clinical and laboratory diagnosis of dengue in Sri Lanka.
(Faculty of Tropical Medicine, Mahidol University, 2007) Hapugoda, M.D.; Khan, B.; de Silva, N.R.; Gunasekera, J.; Abeyewickreme, W.
BACKGROUND: In Sri Lanka, diagnosis of dengue mainly depends on clinical signs and symptoms. Very few suspected patients from the state and private sector health institutions are tested by laboratory diagnostic assays compared to the number of dengue cases recorded all over the island. OBJECTIVES: To correlate clinical parameters with laboratory diagnosis in confirmation of dengue. RESEARCH DESIGN: Patients, clinically suspected of having dengue (n=201) were selected based on WHO criteria. Serum samples were tested using major 3 types of laboratory diagnostic assays; molecular, virus isolation and serology. Differences in clinical and laboratory data were analyzed on the basis of the final diagnosis assigned as dengue or non-dengue. Chi-square test was used for comparison of data. RESULTS: The proportion of laboratory diagnosed dengue patients were 80% (162/201). Mean platelet value and PCV in laboratory confirmed dengue patients were 92 247/mm3 (range 20 000-318 000) and 45% (range 31-59%) respectively. On comparison of the presence of clinical features that are used by the WHO for diagnosis of dengue, headache (129/162 vs 18/39, x2=23, p=0.00), limb pain (107/162 vs 18/39, x2=4.56, p=0.03) and external bleeding (67/162 vs 00/39, X2=27, p=0.00) showed significant association, with dengue infection. The infection was confirmed as definitive dengue in 75% (121 /162) and probable dengue in 25% (41/162). DISCUSSION: 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 is needed in country like Sri Lanka.
Potential use of IGR Pyriproxifen for control of dengue vector Aedes albopictus
(Sri Lanka College of Microbiologists, 1999) Gunawardene, Y.I.N.S.; de Silva, N.R.; Abeyewickreme, W.
Dengue Fever (DF) Dengue Haernorrhagic Fever (DHF) is now a significant problem in Sri Lanka. The incidence of DHF has increased cyclically since the first recognized outbreak in 1989. Of the 203 suspected DHF cases recorded in 1989, 87 were confirmed and 26 deaths were reported. By 1997, 5882 clinical cases, 1558 serologically confirmed cases and over 300 deaths have been reported. Without an effective vaccine against dengue, and considering the clinical difficulty in managing DHF cases, vector control has become an important com¬ponent in the integrated attempts for dengue con¬trol. Aedes aegypti and Aedes albopictus not only transmit dengue but are also a nuisance and cause annoyance by their day biting behaviour. In this study an attempt was made to control Ae. albopictus by exploiting its oviposition behaviour, us¬ing an Insect Growth Regulator (IGR), Pyriproxifen. The IGR is known to interfere with the synthesis and deposition of chitin in insects and thereby prevent growth and development. Different concentrations of the IGR (0.01 g/1 -0.08g/1) were tested against Ae.albopictus, in laboratory experiments. The most effective larvisidal concentration of Pyriproxifen for Ae.albopictus was determined to be 0.03g/1. Field trials were also carried out to determine the feasi¬bility of employing used automobile tyres contain¬ing Pyriproxifen as ovitraps against Ae.albopictus. Tyres containing water were treated with Pyriproxifen (0.03g/1) and the emergence of adults was recorded. Pyriproxifen at a concentration of 0.03g/1 was found to inhibit the emergence of adult Aedes mosquitoes up to 6 weeks.

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