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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty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 Intestinal parasitoses and the nutritional status of internally displaced children in Vavuniya(Sri Lanka Medical Association, 2005) Chandrasena, T.G.A.N.; Hapuarachchi, H.A.C.; Dayanath, M.Y.D.; de Silva, N.R.OBJECTIVES: To assess the prevalence of intestinal parasitic infections and the nutritional status of children of internally displaced families residing in refugee camps. MeTHODOLOGY: Saline smears and modified Kato Katz techniques were performed on stool samples collected from children of displaced families residing in the Adappankulam refugee camp in Vavuniya. The heights and weights of the children were measured and standard anthropometric indices, weight- for-height (WH), Height- for- age (HA) and weight- for- age (WA) Z scores were calculated using Epi Info. RESULTS: Stool samples of 159(83 males) of 200 children registered at Adappankulam refugee camp were screened for intestinal parasites. The mean age of the study population was 7.0 years (range 2-15 years). One or more intestinal parasites were detected in 40.25 % (64/159). Twenty point one percent had helminth and 24.5% (39) had protozoan infection. Of 32 children with helminth infections, 29(18.2%) had hook worm, 2(1.25%) Ascaris lumbricoides, 3 (1.8%) Trichuris trichiura and 1(0.62%) Enterobius .vermicularis infections. The most common pathogens were hookworm and Giardia lamblia (23, 14.5%). The anthropometric indices of 161 children (100 males) were calculated. Of the 105(65.2%) children with growth retardation, 76(47.7%) were wasted 56(34.7%) stunted and 122(75.7%) underweight. There was no significant correlation of the mean Z scores with Giardia or hookworm infection. CONCLUSIONS: There was an elevated prevalence of growth retardation among this group of displaced children. The prevalence of'Giardia and hookworm infections was moderately high. Other pathogenic intestinal parasites were scarce in this community.Item 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 Recent chikungunya outbreak in Sri Lanka 2006-2007(Faculty of Tropical Medicine, Mahidol University, 2007) Abeyewickreme, W.; Bandara, K.B.A.T.; Dayanath, M.Y.D.; Sumanadasa, D.; Hapuarachchi, H.A.C.; Gunawardena, N.K.; Hapugoda, M.D.; Wijesiriwardena, B.; de Silva, S.; Perera, T.BACKGROUND: Chikungunya(CHIK) is a viral disease transmitted by Aedes mosquitoes. Cases with symptoms of CHIK had been reported from several parts of Sri Lanka in 2006-2007. Laboratory testing of samples is a prime requirement for confirmation of transmission. OBJECTIVES: To confirm CHIK infection in suspected patients by rapid Reverse Transcription Polymerase Chain Reaction Assay(RT-PCR), find out manifestations specific for CHIK infection and study the transmission of CHIK virus by vector mosquitoes. METHODOLOGY: Serura. samples and information on clinical manifestations were collected from 189 chikungunya-suspected patients from different geographical areas in Sri Lanka from September 2006 to September 2007. Samples were tested for Chikungunya RNA by RT-PCR. Amplified products were visualized by agarose gel electrophoresis. Adult mosquitoes were also collected from chikungunya case-reported stations. They were tested for Chikungunya RNA through RT-PCR-followed by agarose gel electrophoresis assay. RESULTS: Of the CHIK-suspected patients reported from all parts of the island 86/189 (45.5%) were positive for CHIK virus. Of the PCR positive 06, all had fever with either arthralgia or arthritis or both. Headache (95.3%) and backache (84.6%) were also common among above patients. Eight percent (4/50) of both species of Aedes mosquitoes were RT-PCR positive. DISCUSSION: RT- PCR is important in early diagnosis of the infection and differentiation from dengue fever. The most common clinical symptoms observed were fever with either arthralgia, arthritis or both. Both Aedes aegypti and Aedes. albopictus are important in transmitting the disease.Item Transmission study of dengue fever in Gampaha District, Sri Lanka(Faculty of Tropical Medicine, Mahidol University, 2007) Hapangama, H.A.D.C.; Gunawardene, Y.I.N.S.; Hapugoda, M.D.; Dayanath, M.Y.D.; Abeyewickreme, W.RATIONALE: Dengue is an important flaviviral infection in Sri Lanka.OBJECTIVES; To determine the effect of possible contributing factors on transmission of Dengue METHODS: A total of 40 households situated around 7 selected dengue cases confirmed by both IgM-IgG ELISA and HAI assay were taken. A minimum of 3 inhabitants from each household were tested for anti-dengue antibodies. At each household, mosquito surveillance was carried out. RESULTS: Of the 40 households, 26(65%) were positive for dengue viral infection. Of the 148 inhabitants, 41 had evidence of exposure to dengue. Of the 41. asymptomatic dengue infection was observed in 25(61%). Paired sera were collected from 36/41 volunteers and tested by HAI assay which confirmed dengue virus infection in 4(11.1%) and were confirmed secondary. Three (75%) of them were asymptomatic. Balance 32(88.9%) was diagnosed as recent dengue infections. Of that 21(65.6%) were asymptomatic probable secondary 7(33.3%), recent dengue 14(66.6%)]. Clustering of cases was observed in all localities varying from 56.5%. There was a significant statistical association between the presence of a definitive dengue infection with the presence of Aedes vectors (x2=3.1, p=0.1). Ae. albopictus were found in all localities 'while Ae. aegypti was found only in one. Breteau index for Ae. albopictus varied from 0-260 while- container index varied from 0-84%. Highest clustering of dengue cases were observed in localities with the highest indices for' mosquitoes. CONCLUSIONS: Study confirms that the presence of asymptomatic infections and clustering of cases. The predominant vector was Ae. albopictus.Item A Comparative retrospective study of novel Reverse-Transcription Polymerase Chain Reaction-based Liquid Hybridization (RT-PCR-LH) assay with Polymerase Chain Reaction (PCR) amplification, virus isolation and serological techniques for early, definitive laboratory diagnosis of dengue infection(Malaysian Society of Parasitology and Tropical Medicine, 2007) Hapugoda, M.D.; de Silva, N.R.; Khan, B.; Gunasena, S.; Dayanath, M.Y.D.; Abeyewickreme, W.Dengue is an important vector borne viral infection in South East Asia. Dengue virus is responsible for dengue fever, dengue haemorrhagic fever and dengue shock syndrome. Early diagnosis of infection helps in monitoring the disease, determining when hospital admission is necessary and in reducing case fatalities. The objective of the study was to carry out a comparative retrospective study of a novel Reverse Transcription-Polymerase Chain Reaction-based Liquid Hybridization (RT-PCR-LH) assay with PCR amplification, virus isolation and serological techniques for laboratory diagnosis of dengue infection. Amplified products of Non Structural-3 gene were hybridized with a mixture of the 4 dengue type-specific Deoxyribonucleic Acid (DNA) probes in liquid phase. The assay was validated in a comparative retrospective study using acute serum samples collected from 88 patients with dengue confirmed by Haemagglutination Inhibition (HAI) assay. The assay was highly specific for diagnosis of dengue infection. As an early (<5 days of fever) laboratory diagnostic method, this assay had 100% sensitivity for detection of dengue patients confirmed by HAI assay. A high analytical sensitivity of 2 fluorescent focus units of dengue virus/reaction was achieved. Novel RT-PCR-LH assay using a single serum specimen offers distinct advantages of specificity and sensitivity over other diagnostic techniques for early definitive laboratory diagnosis of dengue infection at the time during which serological methods cannot be used.Item Confirmation of 2006 chikungunya outbreak in Sri Lanka using RT-PCR(Malaysian Society of Parasitology and Tropical Medicine, 2007) Abeyewickreme, W.; Bandara, K.B.A.T.; Perera, H.; Dayanath, M.Y.D.; Hapuarachchi, C.Chikungunya, a mosquito-borne viral infection caused by a single-stranded RNA virus of the family Togaviridae, is considered as a rare, non-fatal disease. During February to October 2006, an epidemic of over 1.3 million suspected cases was reported in India and neighbouring countries causing a significant economic loss due to crippling manifestations of this infection. With the outbreak of many viral fevers including dengue and dengue haemorrhagic fever, in October–November 2006, patients with manifestations suggestive of chikungunya such as high fever, headache, arthralgia and arthiritis (particularly, in ankle, knee and small joints of hands) were reported in many parts of Sri Lanka. As no chikungunya cases had been officially reported in the island since 1969, laboratory investigations for the presence of chikungunya virus was a prime requirement for confirmation of the outbreak. A total of 60 venous blood samples collected from suspected patients from different geographical regions of Sri Lanka were analysed using a reverse transcriptase-polymerase chain reaction (RT-PCR) technique to confirm the presence of chikungunya virus. Viral RNA was extracted from samples collected within 1-4 days of fever by using a Qiagen RNA extraction kit. RT-PCR was performed using chikungunya specific oligonucleotides. Both positive and negative controls were included in each set of reactions. The amplified products (354 bp) were visualized by running in a 1.5% agarose gel followed by ethidium bromide staining. Of the 60 samples, 33 (55%) were positive for chikungunya. They were distributed among almost all the geographical regions, highlighting the presence of a wide-spread epidemic in the country.Item Re-emergence of chikungunya in Sri Lanka: First confirmation of the 2006 outbreak by molecular diagnosis(Sri Lanka Association for the Advancement of Science, 2007) Perera, E.D.T.; Wijesiriwardena, B.; Hapugoda, M.D.; Bandara, K.B.A.T.; Dayanath, M.Y.D.; Wellawaththage, L.C.; Gunawardena, N.K.; Hapuarachchi, C.; Abeyewickreme, W.Chikungunya virus infection is clinically similar to many other acute febrile illnesses, such as dengue infection, malaria, west nile fever and leptospirosis. Rapid confirmation of the outbreak by laboratory diagnosis is important to ensure public health safety by appropriate patient management and controlling the disease. Molecular diagnosis by Reverse Transcriptase- Polymerase Chain Reaction (RT-PCR) assists rapid diagnosis. The objective of the present study was to determine the clinical manifestations of chikungunya confirmed patients in Sri Lanka. Venous blood samples and clinical information were collected from 66 chikungunya suspected patients having fever of less than 4 days from different geographical areas in Sri Lanka during the period September 2006 to February 2007. Serum samples were tested for chikungunya RNA by RT-PCR. Amplified products were visualized by agarose gel electrophoresis. Among 66 suspected patients, 51% (34/66) were positive for chikungunya by RT-PCR assay and 55.9% (19/34) were females. All age groups were affected similarly with the mean age of 41 years (range = 4 months to 80 years). Of the PCR positive 34, all had fever with either arthralgia or arthritis or both. Most of them had only pain in the joints without swelling (arthralgia only); 67.6% (23/34) in knee, 55.9% (19/34) in ankle, 50% (17/34) in wrist, 44.1% (15/34) in elbow and 52.9% (18/34) in small joints. Arthritis of ankle joint 35.2% (12/34) was more frequent compared with arthritis of the knee joint17.6% (6/34). PCR positive patients manifested more symptoms compared with PCR negative patients; 85.3% (29/34) headache, 79.4% (27/34) backache, 58.8% (20/34) nausea and 61.8% (21/34) vomiting. Compared with dengue, most of the chikungunya patients did not have dermatological manifestations. This is the first confirmation of the 2006 chikungunya outbreak in Sri Lanka. Some of the patients who had symptoms suggestive of chikungunya, tested by PCR were negative. These patients were probably suffering from other illnesses such as dengue. Acknowledgements: The International Atomic Energy Agency (TC SRL 6/028) for technical cooperationItem K76T point mutation of chloroquine resistance transporter gene: Is it a potential molecular marker for chloroquine resistance in Sri Lankan Plasmodium falciparum isolates?(Sri Lanka Association for the Advancement of Science, 2007) Hapuarachchi, H.A.C.; Dayanath, M.Y.D.; Abeysundara, S.; Manamperi, A.; Abeyewickreme, W.; de Silva, N.R.Current evidence suggests that K76T mutation of chloroquine resistance transporter (Pfcrt) gene may be used as a molecular marker for chloroquine (CQ) resistance of P. falciparum. This study was carried out to determine the frequency of K76T mutation of Pfcrt gene in Sri Lankan P. falciparum isolates collected from Mannar district in the Northern Province. Mutation patterns were compared with in vitro and in vivo CQ failure rates for this parasite population to analyze its association with resistance to CQ and to calculate the genotype-resistance (GRI) and genotype-failure (GFI) indices for K76T mutation. P. falciparum DNA was extracted from dried blood spots using a QiaAmp DNA Blood Mini Kit. Mutation patterns at 76 codon of Pfcrt of field isolates were detected using a polymerase chain reaction - restriction fragment length polymorphism assay. Parasite isolates were categorized into wild (sensitive) and mutant (resistant) types based on the banding patterns of digested products on 2% agarose gels. GRI and GFI indices were calculated for this parasite population. Of 38 CQ resistant isolates, 86.8% (N = 33) showed the mutant allele (K76T) at codon 76 of Pfcrt. There was a statistically significant association between the presence of K76T mutation and in vivo resistance to CQ (x2 = 5.11, p = 0.02). Of 33 sensitive isolates, 39.4% (N = 20) possessed the wild type allele at the same codon position. The calculated GRI and GFI indices were 1.13 and 1.38 respectively for this area. Even though results show a statistically significant association between the presence of K76T allele and CQ treatment failure of P. falciparum isolates in the study population, its mere presence alone does not seem to correlate with resistance to CQ. Therefore, mutations at other codons of Pfcrt shown to accompany K76T mutation as well as those in P. falciparum multi drug resistance 1 (Pfmdr1) gene need to be analyzed to determine whether other mutations play a role together with K76T in clinically resistant Sri Lankan parasite isolates. More studies are required to validate the calculated GRI and GFI values, which may be used to predict the therapeutic failure of CQ in a particular area in Sri Lanka in the future. Acknowledgement: National Science Foundation Research grant SIDA/2005/BT/03 and by the IAEA TC Project SRL 06/028Item Effect of silent transmission and clustering of cases on transmission of dengue in Gampaha district(Sri Lanka Association for the Advancement of Science, 2007) Hapangama, H.A.D.C.; Gunawardene, Y.I.N.S.; Hapugoda, M.D.; Premaratna, R.; Dayanath, M.Y.D.; Abeyewickreme, W.Silent transmission of dengue virus and clustering of cases have been suggested as possible factors for the increasing incidence of dengue fever. Objective of this study was to determine the presence of silent transmission and clustering of cases of dengue fever in the Gampaha District. Study was carried out using cluster investigation method. A cluster consists of family members and immediate neighbours (minimum of 20) of a dengue index-case. Serum samples from volunteers were tested for anti-dengue antibodies using Dengue-Duo-IgM/IgG Rapid Cassette (Panbio diagnostics, Australia). Using 7 index cases, 148 volunteers (68 Males); mean age: 35.9 years were enrolled. Of the 148, 41 had evidence of exposure to dengue virus [positive for IgM: 68.4% (28/41), IgM & IgG: 17% (7/41) and IgG: 14.6% (6/41)]. Out of 28 primary infections, 71.4% (20/28) were asymptomatic. Of the 7 secondary infections, 14.28% (1/7) was asymptomatic. Of the 6 previous exposures to dengue, 4 (66.67%) were asymptomatic. There was no significant association between sex and exposure to infection [31% (21/68) males vs 25% (20/80) females, p>0.05] or between sex and occurrence of symptoms among exposed individuals [71% (15/21) males vs 50% (10/20) females, p>0.05]. Older individuals aged over 40 years, were most likely to be asymptomatic than younger persons (94% (14/15 exposed) vs 50% (13/26 exposed), P<0.01). Out of 7 clusters investigated, 1 had >50%, 4 had >25% and 2 had <25% clustering effects. A high proportion of asymptomatic infections were observed among adults over 40 years without gender difference. Study suggests persistence of silent transmission of dengue virus with a trend towards clustering around cases. Acknowledgement: World Health Organization (WHO/SEARO SN1144) and technical co-operation by International Atomic Energy Agency (TC/SRL 06/28)Item A Comparative retrospective study of RT-PCR-based liquid hybridization assay for early, definitive diagnosis of dengue(Oxford University Press, 2010) Hapugoda, M.D.; de Silva, N.R.; Khan, B.; Dayanath, M.Y.D.; Gunesena, S.; Prithimala, L.; Abeyewickreme, W.Dengue is an important flaviviral infection in tropical and subtropical regions. Early diagnosis of dengue infection helps in monitoring the disease, determining when hospital admission is necessary and reducing case fatalities. The objective of this study was to carry out a retrospective comparison of an RT-PCR-based liquid hybridization (RT-PCR-LH) assay with PCR amplification, virus isolation and serological techniques for laboratory diagnosis of dengue infection. Amplified products of non-structural 3 gene were hybridized with a mixture of four dengue type-specific DNA probes in liquid phase. The assay was validated in a comparative retrospective study using acute serum samples collected from 119 fever patients with or without dengue, confirmed by haemagglutination inhibition (HAI) assay, the gold standard assay for diagnosis of dengue infection. The RT-PCR-LH assay was highly specific for dengue and, as an early laboratory diagnostic method, had 100% sensitivity in detecting dengue patients confirmed by HAI assay. A high analytical sensitivity of two fluorescent focus units of dengue virus/reaction was achieved. This RT-PCR-LH assay using a single serum specimen offers distinct advantages of specificity and sensitivity over other diagnostic techniques for early definitive laboratory diagnosis of dengue infection when serological methods are of little value.