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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty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 Evaluating temporal patterns of snakebite in Sri Lanka: The potential for higher snakebite burdens with climate change(Sri Lanka Medical Association, 2018) Ediriweera, D.S.; Diggle, P.J.; Kasturiratne, A.; Pathmeswaran, A.; Gunawardena, N.K.; Jayamanne, S.F.; Isbister, J.K.; Dawson, A.; Lalloo, D.G.; de Silva, H.J.INTRODUCTION AND OBJECTIVES: Snakebite is a neglected tropical disease that has been overlooked by healthcare decision makers in many countries. Previous studies have reported seasonal variation in hospital admission rates due to snakebites in endemic countries including Sri Lanka, but seasonal patterns have not been investigated in detail. METHODS: A national community-based survey was conducted during the period of August 2012 to June 2013. The survey used a multistage cluster design, sampled 165,665 individuals living in 44,136 households and recorded all recalled snakebite events that had occurred during the preceding year Log-linear models were fitted to describe the expected number of snakebites occurring in each month taking into account seasonal trends and weather conditions, and addressing the effects of variation in survey effort during the study and due to recall bias amongst survey respondents RESULTS: Snakebite events showed a clear seasonal variation. Typically, snakebite incidence was highest during November to December followed by March to May and August, but this varied between years due to variations in relative humidity, which is also a risk-factor. Low relative humidity levels was associated with high snakebite incidence. If current climate change projections are correct, this could lead to an increase in the annual snakebite of burden of 35,086 (95% CI: 4 202 a€" 69,232) during the next 25 to 50 years. CONCLUSION: Snakebite in Sri Lanka shows seasonal variation Additionally, more snakebites can be expected during periods of lower than expected humidity. Global climate change is likely to increase the incidence of snakebite in Sri Lanka.Item Development of a Snakebite risk map for Sri Lanka(Sri Lanka Medical Association, 2016) Ediriweera, D.S.; Kasturiratne, A.; Pathmeswaran, A.; Gunawardena, N.K.; Wijayawickrama, B.A.; Jayamanne, S.F.; Isbister, G.K.; Dawson, A.; Giorgi, E.; Diggle, P.J.; Lalloo, D.G.; de Silva, H.J.INTRODUCTION: Snakebite is a public health problem in Sri Lanka and about 37,000 patients are treated in government hospitals annually. At present, health care resources which are required to manage snakebite are distributed based on the administrative boundaries, rather than based on scientific risk assessment. OBJECTIVES: The aim of the study is to develop a snakebite risk map for Sri Lanka. METHOD: Epidemiological data was obtained from a community-based island-wide survey. The sample was distributed equally among the nine provinces. 165,665 participants (0.8%of the country’s population) living in 1118 Grama Niladhari divisions were surveyed. Generalized linear and generalized additive models were used for exploratory data analysis. Model-based geostatistics was used to determine the geographical distribution of snakebites. Monte Carlo maximum likelihood method was used to obtain parameter estimates and plug-in spatial predictions were obtained. Probability contour maps (PCM) were developed to demonstrate the spatial variation in the probability that local incidence does or does not exceed national snakebite incidence. RESULTS: Individual point estimate snakebite incidence map and PCM were developed to demonstrate the national incidence of snakebite in Sri Lanka. Snakebite hotspots and cold spots were identified in relation to the national snakebite incidence rate. Risk maps showed a within-country spatial variation in snakebites. CONCLUSIONS: The developed risk maps provide useful information for healthcare decision makers to allocate resources to manage snakebite in Sri Lanka.Item Achieving millennium development goal 4 in 2015: are we really on track?(Sri Lanka College of Paediatricians, 2011) Mettananda, S.; Rajindrajith, S.; Warnakulasuriya, T.; Fernando, M.; Devanarayana, N.M.; Gunawardena, N.K.INTRODUCTION: Millennium development goal (MDG) 4 aims to reduce under 5 mortality by two thirds from 1990 (22.2 per 1000 live births) to 2015 (7.4 per 1000 live births). In achieving this, proper and accurate description of the causes of deaths is crucial. OBJECTIVES: To describe the timing, causes and distribution of under 5 child deaths in Sri Lanka and to predict the likelihood of achieving MDG 4. DESIGN, SETTING AND METHOD: Information regarding all under 5 child deaths between 2002-2006 was obtained from the Registrar Generals' Department. Place, sex and age at death were retrieved. Causes of deaths documented accordingly to the ICD-10 classification were reclassified into clinically relevant and user-friendly categories. Mortality rates and predictions for 2015 were calculated using Microsoft Excel. RESULTS: A total of 26,273 deaths have occurred during 2002-2006 [55% neonatal, 21% post-neonatal infant and 24% child (l-5year)]. Tsunami wave in 2004 had caused 2,868 (11%) deaths and they were excluded from further analysis. Prematurity had caused 4,603 (31.8%) neonatal deaths; 2389 (16.5%) were due to infections and 1149 (7.9%) were due to birth asphyxia. Congenital anomalies have contributed to 1830 (12.6%) neonatal deaths, of which, the majority [1389 (9.6%)] were heart diseases. Leading causes for post-neonatal infant deaths include congenital anomalies [1772 (35%)], infections [1516 (29.9%)] and trauma [393 (7.7%)]. in children, 910 (23.4%) deaths were due to infections (10.2% respiratory, 2.0% gastroenteritis and 0.9% dengue). One fifth of deaths were due to congenital anomalies of which half were due to heart defects. Trauma/ accidents and malignancies had contributed to 731 (18.8%) and 279 (7.1%) deaths respectively. Colombo district reported the highest number of deaths (24%). More males (54.7%) have died compared to females. Reduction in mortality rates were observed from 2002-2006; neonatal mortality from 8.3 to 7.6, infant mortality from 11.4 to 10.4 and under 5 mortality from 13.7 to 12.3. Projections of data showed that the neonatal, infant and under 5 mortality rates in 2015 would be 4.6, 6.7 and 7.7 per 1000 live births respectively. CONCLUSIONS: Prematurity was the leading cause of neonatal mortality. Congenital heart diseases are an important cause of death throughout childhood. Trauma and accidents contribute to a significant proportion of child deaths. Predictions from data suggest that Sri Lanka may fall marginally short of achieving MDG 4.Item Effect of genotyping on the severity of rotavirus Gastroenteritis(Sri Lanka College of Paediatricians, 2011) Chandrasena, T.G.A.N.; Rajindrajith, S.; Gunawardena, N.K.; Silva, G.M.K.S.; Pathmeswaran, A.; Kazuhiko, M.; Kamruddin, A.INTRODUCTION: Rotavirus is the commonest cause of paediatric gastroenteritis. There remains a controversy regarding disease severity being related to rotavirus genotype G9. OBJECTIVE: Study the genotype related severity of rotavirus gastroenteritis. DESIGN, SETTING AND METHOD: All children under 5 years of age who were admitted with acute diarrhoea to North Colombo Teaching Hospital and submitted a sample of stool for analysis from April 2005 to October 2008 were selected for the study. Clinical information was collected regarding the study group. Acute diarrhoea was defined as passage of 3 times or more stools over a period of 24 hours. Stools were collected from cases with blood and mucus diarrhoea as well. The stool compliance rate was around 75-80%. Faecal specimens were tested and genotyped for rotavirus using the ELISA kit, Rotaclone® (Meridian Diagnostics, Cincinnati) and reverse transcription (RT) PCR respectively. Severity of gastroenteritis was assessed using the 20 point scoring system ofVesikariand Ruuska. RESULTS: The total number of stool specimens collected during the study period was 813 and of this 178 were positive for group A rotavirus; all the rotavirus positive stool specimens were genotyped. The two predominant VP7 genotypes were G9 (76; 42.7%) and Gl (35; 19.7%) followed by G2 (22; 12.4%), G3 (22; 12.4%), G12 (18; 10.1%) and G4 (4; 2.2%) respectively. The mean severity scores of, Gl, G2, G3, G4, G9 and G12 were 12,12,12,14,13 and 13, respectively. Comparison of clinical features between the two common G types, G9 and Gl revealed the following: duration of diarrhoea was longer among G9 (mean 4±2 days) than Gl (mean 2±1 day) and a higher percentage of cases were febrile and had vomiting in G9 (84.9 and 86.3 respectively) than Gl (76.7 and 65.5 respectively) infections (p>0.05). The rest of the clinical features were similar. The percentage with severe disease (score >14) was higher among the G9 (38.4) than among Gl (26.7) infections (p>0.05). CONCLUSION: Although rotavirus G9 genotype was associated with a more severe gastroenteritis than the common Gl genotype, this association was not significant (p>0.05).Item Prevalence of enterobiasis among primary school children in Ragama MOH region(Sri Lanka College of Microbiologists, 2012) Gunawardena, N.K.; Chandrasena, T.G.A.N.; Senarathna, B.P.; Silva, G.M.K.S.; de Silva, N.R.INTRODUCTION: Although frequently diagnosed clinically, there is only one previously reported survey of Enterobius vermicularis infection among Sri Lankan children, conducted in the 1980s. OBJECTIVES: To determine the prevalence of enterobiasis among Year One school children in Ragama MOH area and investigate association between infection and risk factors. METHOD: A cross sectional descriptive study was performed among Year One children in seven randomly selected schools. Infection was diagnosed using adhesive cellophane peri-anal swabs obtained on two consecutive days. A pre-tested, self-administered questionnaire completed by the mother, identified risk factors associated with enterobiasis. Initial univariate analysis was followed by multivariate analysis with logistic regression. RESULTS: Of 322 children, 276 (male: female ratio 1.1:1, mean age 6 years) returned the swabs and questionnaires (compliance 85.7%). Prevalence of infection by double and single swab examination was 37.5% and 20.1% respectively. Prevalence was significantly lower among children of more educated mothers (34.2%), fathers with permanent employment (28.9%) and those dewormed in the last 30 days (22%) compared to children of less educated mothers (46.5%), fathers with casual (46.9%) or no employment (36.4%) and those not dewormed recently (41.6%)(P<0.05). Infected children belonged to households with significantly more members, siblings and persons sleeping with index child (P<0.05). Multivariate analysis showed that more children in a household and recent deworrning were the only significant determinants of enterobiasis. CONCLUSIONS: Over one-third of primary school children in the Ragama MOH area have enterobiasis. The risk of infection is higher in families with more children and is reduced by regular deworrning.Item Randomized placebo-controlled trial of the efficacy of mebendazole polymorphs in the treatment of hookworm infections(Sri Lanka College of Microbiologists, 2013) Gunawardena, N.K.; Kumarendran, B.; Manamperi, N.H.; Senarathna, B.P.; Silva, M.; Pathmeswaran, A.; de Silva, N.R.INTRODUCTION: Mebendazole has three polymorphic forms, identified as A, B and C. Animal studies and one previous study in humans have suggested that unlike polymorph C, polymorph A is ineffective in the treatment of hookworm and whipworm infections. OBJECTIVES: A randomized double-blind, placebo-controlled trial was carried out to compare the efficacy of single dose 500 mg tablets of pure mebendazole polymorph C with those containing a 1:1 mixture of polymorphs Aand C, for the treatment of hookworm infections. . DESIGN, SETTING AND METHODS: All eligible individuals living in 219 households in 8 estate divisions in Ratnapura District known to have a high prevalence of hookworm, were recruited after obtaining written, informed consent. A single faecal sample was obtained and examined the same day, using the Kato-Katz technique for quantification of intestinal nematode infections. Those who were found infected with hook¬worms were randomized to one of three treatment arms and requested to provide a second faecal sample 10-14 days after treatment. This was examined in the same manner as the first. RESULTS: A total of 892 individuals were recruited; 601 provided faecal samples; 214 were found positive for hookworm infection; 70, 74 and 70 individuals were randomized to treatment arms A (mixture of polymorphs A and C), B (pure polymorph C) and C (placebo) respectively. Follow-up faeca! samples were provided by 53,48 and 49 persons respectively in each treatment arm. The cure rates in the three treatment arms were 28.3%, 18.8% and 16.3% respectively; they were not significantly different from one another. Comparison of faecal egg count reductions (FECR) in the 3 treatment arms (86.1%, 84.5% and -6.6% in arms A, B and C respectively) showed that both mebendazole formulations performed significantly better than placebo, but there was no statistically significant difference between FECR with the two drug formulations. CONCLUSIONS: A single SOOmg dose of mebendazole, either as Polymorph C alone, or as a mixture of Polymorphs A and C, has little efficacy in curing hookworm infections. However, both formulations are significantly better than placebo in reducing the intensity of infection, with no statistically significant difference between the two formulations.Item Comparison of laboratory techniques for diagnosis of hookworm infections(Sri Lanka College of Microbiologists, 2011) Manamperi, N.H.; Anjalee, K.G.C.; Gunawardena, N.K.; Sudusinghe, H.; Nilaweera, T.H.W.T.; de Silva, N.R.INTRODUCTION: Hookworm infection may be diagnosed by detection of eggs or culturing of larvae from stools. OBJECTIVE: To compare the efficacy of modified Kato-Katz (K-K) technique, saline smears, Harada-Mori (H-M) and nutrient agar culture plate (NACP) methods in diagnosis of hookworm infections. METHODOLOGY: A total of 324 stool samples, from the plantation sector families in Ratnapura district were examined by modified Kato-Katz technique and saline smears, and cultured by Harada-Mori and on NACP according to standard protocols, at the Faculty of Medicine, Ragama. Harada-Mori and NACP were maintained for 7-10 days and larvae or larval tracts observed by a stereomicroscope. Positivity in any two of the four techniques was considered the gold standard positive. Statistical analysis was done using SPSS version 16. RESULTS: A total of 172 (53.1%) samples were positive by at least one method. The positivity rates with K-K, H-M, NACP and saline smears were 42.3% (137/324), 37.7% (122/324), 23.5% (76/324) and 22.2% (72/324) respectively. The highest sensitivity (89.8%) and lowest specificity (88.3%) was seen in modified K-K, the lowest sensitivity (50.4%) in saline smears and the highest specificity in NACP (98.5%). Detection rates with saline smears, H-M and NACP rose with increasing intensity of infection as determined by K-K technique. Harada-Mori had the highest detection rate (70.7%) in light infections. It also detected 11.8% of K-K negative samples. CONCLUSIONS: The modified K-K technique is a reasonably good diagnostic method for detection of hookworm infections. A combination of methods will increase the diagnostic accuracy in hookworm infections.Item Intestinal parasitic infections among a selected group of institutionalised psychiatric patients(Sri Lanka College of Microbiologists, 2009) Chandrasena, T.G.A.N.; Gunawardena, N.K.; Imbulpitiya, I.V.B.; Balasooriya, B.A.D.H.; Ariyarathna, W.P.H.; de Silva, N.R.INTRODUCTION: Patients with chronic psychiatric illnesses are known to be at high risk of intestinal parasitic infections because of poor attention to sanitation and hygiene. OBJECTIVES: To determine the prevalence of intestinal parasitic infections among inmates of a psychiatric institution in Sri Lanka. METHODS: Faecal samples of randomly selected patients at the Half-way Home, Mulleriyawa (HHM) were examined using saline and modified Kato Katz smears. RESULTS: Of 649 female patients at HHM 22% (145) were screened for intestinal parasites. The mean age of study population was 50 years (range 26-75). One or more intestinal parasites were detected in 35% (51/145). Thirty percent (44/145) had only helminth infections, 2.8 % (4/145) were co-infected with helminth and commensal protozoa Entamoeba co//and 2% (3/145) had only E.coli. Of the 48 who had helminth infections 6.8% (10/145) had Ascaris lumbricoides, 10.3% (15/145) had Trichuris trichiura and 15.8% (23/145) had mixed infections of A. lumbricoides and T. trichiura. Proportions of patients with varying intensities of infections with respect to A, lumbricoides and T. trichiura were light in: 51.6% (16) and 55.6% (20), moderate in 45.16% (14) and 44.4% (16) and heavy in 3.2% (1) and 0% respectively. Forty six percent (67/145) and 12.5% (18/145) had been dewormed within one year and three months respectively. Thirty five percent (17/48) of parasite positive patients had been dewormed within one year. CONCLUSION: Although the prevalence of faeco-orally transmitted protozoan infections were scarce, the prevalence and intensity of geohelminth infections were high among the inmates of the HHM mental institution. Improvements in sanitation, provision of safe food and water and regular mass deworming are recommended.Item Surveillance of rotavirus in three hospital settings of Sri Lanka 2007 - 2010(Sri Lanka College of Microbiologists, 2014) Chandrasena, T.G.A.N.; Rajindrajith, S.; Gunawardena, N.K.; Liyanarachchi, N.; Abeysekera, C.K.; Matsomoto, T.; Yahiro, T.; Nishizono, A.; Ahmed, K.INTRODUCTION: Rotavirus is an important aetiological agent of childhood diarrhoeas in Sri Lanka. OBJECTIVES: To study the rotavirus epidemiology and genotypic diversity of cases hospitalized in three geographical locations of Sri Lanka, Ragama, Galle and Kandy. MATERIALS AND METHODS: The study was approved by the ethical review board of the Sri Lanka College of Paediatricians. Stool samples were collected from children < 5 years, hospitalized at the Teaching Hospitals at Ragama (RTH) (November 2007 - October 2010) Galle (GTH) and Kandy (KTH) (mid and late 2008) respectively for acute gastroenteritis. Rotavirus was detected using EIA kit, Rotaclone®. A subset of rotavirus positive samples was genotyped by reverse-transcription(Rt)-PCR and polyacrylamide-gel-electrophoresis (PAGE). RESULTS: Stool samples of 1245 children (69.2%, 23.3% and 7.3% from RTH, GTH and KTH respectively) were screened for rotavirus. Of them, 476 were positive by EIA. The overall rate of prevalence of rotavirus infection was 38.2%. The median age of infection ranged from 13-20 months. Rotavirus genotyping was done on 375 (78.8 %) samples. G1 [P8] was the overall dominant strain (44.8%) followed by G9[P8] (10.1%), G2[P4] (5.3%), G3[P8] (3.2%), G1[P6] (2.1%), G12[P6] (1.3%), G2[P8] (1.06%) and 0.26% of G4[P6], G4[P4] and G4[P8]. The G or P serotype was untypable in 25.6% of samples and 5.6% were of mixed-G and P type. PAGE yeilded 25 electropherotypes (E1-E12 and E16-E29), with E5 and E20 causing 19 and 14 percent of infections respectively. The electropherotype could not be determined in 26%. CONCLUSIONS: Rotavirus continues to be an important cause of childhood diarrhoreas in Sri Lanka. Strain G1P8 predominated in all areas during the surveillance period with a notable percentage of mixed-G and P infections. Multiple E types identified indicate increasing strain diversityItem Soil-transmitted helminthiases in Sri Lanka(Faculty of Medicine, University of Kelaniya, Sri Lanka, 2016) Gunawardena, N.K.During the period 2000 – 2015, the Dept of Parasitology has conducted several studies to assess the prevalence of STH infections in Sri Lanka. Three studies in particular will be highlighted. In 2003, a national study on the health status of primary schoolchildren included assessment of the prevalence of STH infections among approximately 2500 primary schoolchildren in all 9 provinces. The island-wide cumulative prevalence of STH was estimated to be 6.9%. In 2009, a study was carried out to assess the status of STH infection among approximately 2000 school children in the estate sector. At 29.0%, the prevalence rates were above the level at which the WHO recommends introduction of annual mass de-worming. In 2012, the prevalence of STH infections was assessed in the inland and coastal areas of Gampaha district along with a transmission assessment survey for lymphatic filariasis (LF). The STH rates were very low: 0.8% (inland) and 2.8% (coastal). These results also suggested that it is feasible to integrate school-based surveillance for STH and LF.