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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty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 Lymphatic filariases and soil-transmitted helminthiases in Sri Lanka: the challenge of eliminating residual pockets of transmission(The Royal Society, 2023) Chandrasena, T.G.A.N.; Gunaratna, I.E.; Ediriweera, D.; de Silva, N.R.Sri Lanka has successfully met the challenge of controlling both lymphatic filariasis (LF) and soil-transmitted helminthiases (STH) as public health problems. The primary public health strategy for combatting both conditions has been preventive chemotherapy. The national programme for the elimination of LF implemented five annual rounds of mass chemotherapy in the endemic districts from 2002 to 2006 using a combination of diethylcarbamazine and albendazole. The overall microfilaria rate declined from 0.21% in 2001 before the mass chemotherapy, to 0.06% in 2016, at declaration of elimination of LF as a public health problem by the World Health Organization. Currently Sri Lanka is in the phase of post-validation surveillance. Achieving control of STH has been more difficult. Mass deworming programmes have been implemented for nearly a century, and national-level surveys reported prevalence rates declining from 6.9% in 2003 to 1% in 2017. However, neither of these infections has been completely eliminated. A situation analysis indicates continued transmission of both among high-risk communities. This paper explores the reasons for persistence of transmission of both LF and STH in residual pockets and the measures that are required to achieve long-term control, or perhaps even interrupt transmission in Sri Lanka. This article is part of the theme issue 'Challenges and opportunities in the fight against neglected tropical diseases: a decade from the London Declaration on NTDs'.Item Annotated checklist of chigger mites (Trombidiformes: Leeuwenhoekiidae, Trombiculidae and Walchiidae) in Sri Lanka(Elsevier, 2022) Ashani, M.L.S.; Gunathilaka, P.A.D.H.N.; Premaratna, B.A.H.R.; Chandrasena, T.G.A.N.; Jacinavicius, F.C.; Silva, R.B.Chigger mites (Leeuwenhoekiidae, Trombiculidae, and Walchiidae) are parasites of any terrestrial vertebrate. The present study updates the list of chigger mite (Trombiculidae, Leeuwenhoekiidae, and Walchiidae) species recorded from Sri Lanka along with taxonomic classification based on previous investigations since 1946 to date and our observations in western and southern parts of the country. This checklist listed 15 species in 9 genera within the three chigger families. For now, murid species were the host most sampledparasitized by chiggers in Sri Lanka. However, further studies are required to increase the diversity of chigger mites in Sri Lanka and probably the description of new species, which will be possible with morphological and molecular characterization.Item Lymphatic filariasis in the Southeast Asian region; status and control options.(CABI Publishing, 2020) Chandrasena, T.G.A.N.; Premaratna, R.; Mallawarachchi, C.H.; Gunaratna, D.G.A.M.; de Silva, N.R.ABSTRACT: The Global Program to Eliminate Lymphatic Filariasis (GPELF) was launched in year 2000 by the World Health Organization (WHO) with the goal set for elimination by 2020. Over half the global disease burden lies in the Southeast Asian region (SEAR). The preventive chemotherapy (PC) programme has been initiated in all the WHO SEAR member states with varying levels of progress. Maldives, Sri Lanka and Thailand have achieved the goal of elimination as a public health problem (EPHP) within the stipulated period with Bangladesh working towards validation in 2021. Both Sri Lanka and Thailand are continuing with post-validation surveillance combined with selective treatment, striving for zero transmission in-parallel with the morbidity management and disability prevention program (MMDP). Timor-Leste appears close to reaching critical transmission thresholds with 100% coverage and triple therapy in the last round of PC. Data on MMDP activities are insufficient to comment on reaching EPHP status. PC coverage and country reports indicate ongoing transmission in Nepal, Myanmar, Indonesia and India requiring further rounds of PC. The PELF has made considerable progress in the SEAR towards elimination but there still remain significant transmission and disease burden in the highly populated countries in SEAR.Item Optimization of Aedes albopictus rearing procedures for combined sterile insect techniques (SIT) and Wolbachia-based laboratory studies in Sri Lanka(Springer Science and Business Media Deutschland GmbH, 2020) Wijegunawardana, N.D.A.D.; Gunawardene, Y.I.N.S.; Abeyewickreme, W.; Chandrasena, T.G.A.N.; Dassanayake, R.S.; Manamperi, A.The establishment of a laboratory colony is an essential first step for conduction of laboratory studies on the biology and control of Aedes albopictus mosquitoes. Therefore, with the objective of generating high quality mosquitoes as research material for utilization in ongoing vector control studies and to disseminate authenticated, high-quality Ae. albopictus mosquito rearing information to the research community, maintenance of an Ae. albopictus mosquito colony was initiated at the Molecular Medicine Unit, Faculty of Medicine, University of Kelaniya, Sri Lanka. A self-mating colony was established from eggs of the F1 progeny of individuals collected as free-living larvae in Narahenpita (Western Province), Sri Lanka. The mean temperature of 28 °C (± 2 °C) and relative humidity of 80% (± 5%) was constantly maintained inside the insectary. Lighting was provided by fluorescent lights, regulated with 12:12 h continuous dark and light period. Pest insects were controlled manually. Mosquitoes were maintained on bovine blood provided via an artificial membrane feeding system and a continuous supply of 10% sugar supplements. Larvae were maintained in deoxygenate water and fed with International Atomic Energy Agency (IAEA) recommended diet of tuna meal, bovine liver powder, and brewery yeast in a ratio of 37.5:27:10.5 in 1 L. Data on fecundity, fertility, larvae death, pupation, adult emergence, adult mosquito longevity were recorded. Adhering to bio-safety, all discarded materials were boiled thoroughly and incinerated if required. This report on the establishment and maintenance of a laboratory colony of Ae. albopictus will be of value for identifying the critical requirements essential under artificial conditions.Item Detection of a case of Brugian Filariasis from Anuradhapura, a non-endemic district of Sri Lanka(Sri Lanka Medical Association, 2018) Mallawarachchi, C.H.; Gunaratne, I.E.; Ekanayaka, G.M.G.A.C.; Mallawarachchi, S.M.N.S.M.; Chandrasena, T.G.A.N.; Mendis, D.; de Silva, N.R.INTRODUCTION AND OBJECTIVES: In 2016, the WHO declared that lymphatic filariasis was no longer a public health problem in Sri Lanka. However low-grade persistence of bancroftian filariasis continues in all three endemic provinces, while brugian filariasis has re-emerged. The periodicity pattern of the re-emerged Brugia spp. suggests zoonotic origin. A canine survey done in the district of Anuradhapura found a moderately high prevalence (28.2%) of B. malayi infections in the Thirappane MOH area. Objective of the study was to investigate the threat of zoonotic B.malayi infections to humans in the Thirappane MOH area. METHODS: A cross sectional survey was done among all consenting residents of three randomly selected areas representing the three PHI areas of the Thirappane MOH. Residents were screened between 8.00 pm and 12.00 pm using night blood smears (NBS) and Brugia rapid test (BRT) for presence of anti-Brugia IgG4 antibodies. BRT was done selectively. Ethical and administrative clearance was obtained prior to the survey. RESULTS: A total of 752 individuals were screened by NBS; 176 of them were also screened by BRT. 193, 208 and 351 NBSs were done respectively in Thirappane, Galkulama and Mooriyankadawala PHI areas. One individual, a 25-year-old long-term resident of Mooriyankadawala PHI area was positive for Brugia spp. microfilariae by NBS and by BRT. The microfilariae exhibited nocturnal sub-periodicity. CONCLUSION: Transmission of brugian filariasis appears to occur even outside the traditional endemic belt. The presence of canine reservoirs of infection and water bodies with aquatic vegetation probably favour transmission by Mansonia spp. vector mosquitoes in the study area.Item Human-porcine reassortant rotavirus generated by multiple reassortment events in a Sri Lankan child with diarrhea(Elsevier Science, 2018) Yahiro, T.; Takaki, M.; Chandrasena, T.G.A.N.; Rajindrajith, S.; Isa, H.; Ahmed, K.A human-porcine reassortant rotavirus, strain R1207, was identified from 74 group A rotaviruses detected in 197 (37.6%) stool samples collected from patients who attended a tertiary care hospital in Ragama, Sri Lanka. This is the first report of a human-porcine reassortant rotavirus in Sri Lanka. The patient was a 12-month-old boy who had been hospitalized with fever and acute diarrhea with a duration of 6 days. The family had pigs at home before the birth of this boy. However, the neighbors still practice pig farming. The genotype constellation of R1207 was G4-P[6]-I1-R1-C1-M1-A1-N1-T1-E1-H1. This is based on the assignment of all the eleven gene segments a full genome-based genotyping system. R1207 showed a 4-2-3-2 genomic electrophoretic migration pattern, which is characteristic of group A rotaviruses. Our analyses revealed that five (NSP2, NSP4, VP1, VP2, and VP7) of the 11 genes were closely related to the respective genes of porcine strains. Although the remaining six genes (NSP1, NSP3, NSP5, VP3, VP4, and VP6) were related to human strains, with the exception of the gene sequence of NSP1, all of these human strains were human-porcine reassortants. With a genogroup 1 genetic backbone, this strain was possibly formed via multiple genetic reassortments. We do not know whether this strain is circulating in pigs, as no data are available on porcine rotaviruses in Sri Lanka. Surveillance should be strengthened to determine the epidemiology of this genotype of rotavirus in Sri Lanka and to assess whether the infection was limited or sustained by ongoing human-to-human transmission.Item Clinical Charasteristics of paediatric rickettsioses(Sri Lanka Medical Association, 2013) Premaratna, R.; Karunasekara, K.A.W.; Fernando, M.A.M.; de Silva, L.; Chandrasena, T.G.A.N.; de Silva, H.J.INTRODUCTION AND OBJECTIVES: Rickettsioses are re-emerging in Sri Lanka. Both children and adults are vulnerable to these infections. Data on paediatric rickettsioses in the country are sparse. Objectives were to study the clinical characteristics of paediatric rickettsioses based on data received by the Rickettsail Disease Diagnostic and Research Laboratory (RDDRL), Faculty of Medicine, University of Kelaniya, over the last two years. METHODS: All clinical and laboratory data of confirmed rickettsioses were analyzed. RESULTS: Out of 46 requests received by the RDDRL, 22 were positive for acute rickettsioses in diagnostic titres IFA-IgD>1:128 (all>256). Of the positives, 16 were positive for spotted fever group rickettsioses (SFG), 5 for scrub thypus (ST) and 1 for both. 4/5 ST had eschars. The mean age was 56.59 months. (43.9); the youngest affected was aged 5 months. Of the sample 12 (54.5%) were male. Fever was present in all; mean duration was 9.81 (4.5) days; fever intensity was 102.80F (1.03); frequency of spikers per day was 2.33 (0.67). clinical features were headache 12 (54.5%), body aches 9 (40.9%), joint pains 6 (27.3%), cough 14 (63.6%), shortness of breath 5 (22.7%), rash 14 (63.6%); macular popular rash 13, diarrhea 4 (18.2%), lymphadenopathy 7 (31.8%), palpable liver 4, palpable spleen 1. Total WBC 11.1x109/L (SD-4.8); neurophils-84.8% (SD-13.8) lymphocytes 40.5% (17.2). ESR 1st Hr 46.3mm (SD-26.7) CRP 42.1mg/dl (40.6) SGOT 51.2iu/L (32.1) SGPT 50.2iu/L (51.4). ECG was normal in all, Chest x-ray showed patchy shadows in 4. CONCLUSIONS: SFG rickettsioses were commoner than ST, among children living in the Gampaha and Kurunegale districts. Clinical features were similar to adults. Diagnostic investigations were requested late in the febrile illness.Item Surveillance for transmission of lymphatic filariasis in Colombo and Gampaha districts of Sri Lanka following mass drug administration(Oxford University Press, 2016) Chandrasena, T.G.A.N.; Premaratna, R.; Samarasekera, D.S.; de Silva, N.R.BACKGROUND: Sri Lanka was recently declared by WHO to have eliminated lymphatic filariasis as a public health problem, after conclusion of annual mass drug administration. Our aim was to assess the lymphatic filariasis situation, following mass drug administration. METHODS: Surveillance was done in two districts of the Western Province in two consecutive phases (2009-2010 and 2013-2015), by examining 2461 thick night blood smears and performing 250 dipstick tests on children for antibodies to Brugia malayi. RESULTS AND CONCLUSIONS: Decline in bancroftian microfilaraemia (microfilaria rate 0.32% to zero) supports elimination, but re-emergence of brugian filariasisis (antibody rate, 1.6%; one microfilaria positive) is a cause for concern.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.