Browsing by Author "Hapuarachchi, H.A.C."

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A Case of imported malaria: the first report of Plasmodium malariae infection in Sri Lanka after 37 years
(Sri Lanka Medical Association, 2008) Hapuarachchi, H.A.C.; Gunawardena, N.K.; Senevirathne, M.P.; Abeyewickreme, W.; de Silva, N.R.
We report a case of Plasmodium falciparum and P. malariae mixed infection in a patient who had been living in Malawi. This is the first case of P. malariae reported in Sri Lanka in 4 decades. The presence of both parasites was confirmed by microscopy and polymerase chain reaction (PCR). The history strongly indicated that the infection had been acquired from Malawi. The patient had liver dysfunction and a transient glomerulonephritis, both of which subsided with antimalarial treatment.
A Case report of dengue and chikungunya co-infection in Sri Lanka
(The Parasitology and Tropical Medicine Association of Thailand, 2008) Abeyewickreme, W.; Hapuarachchi, H.A.C.; Bandara, K.B.A.T.; Hapugoda, M.D.; Williams, S.
Dengue fever and chikungunya are arboviral diseases transmitted by Aedes mosquitoes. Though dengue has been an important communicable disease in Sri Lanka for many years, chikungunya has not been reported in Sri Lanka since late 1960s. However, in November 2006, an outbreak suggestive of chikungunya erupted in the country. We report here the first laboratory confirmed case of dengue and chikungunya co-infection in Sri Lanka. The objective is to confirm the co-infection of dengue and chikungunya in a clinical case reported in November 2006. Clinical history of high fever, severe headache, nausea, loss of appetite, severe arthralgia and mild oedema of knees, small joints of hands and feet for 3 days suggested the possibility of dengue and chikungunya in a 70 year old male. There was no skin rash or bleeding manifestations. Laboratory investigations performed included total white blood corpuscle count/differential count (WBC/DC), platelet count (PLT), serum, haemoglobin (Hb%) and packed cell volume levels (PCV). Reverse Transcription- Polyrnerase Chain Reaction (RT-PCR) technology was used to confirm the presence of either dengue or chikungunya. Viral RNA was extracted from serum samples collected during the first five days of infection using QiAmp Viral RNA Kits and amplified products were visualized by 2% agarose gel electrophoresis and ethidium bromide staining. WBC/DC analysis showed a leucopaenia (WBC count 3.04 x 103 per μl) with relative lymphocytosis (51.0%). The total PLT was 115 x 103 per μl. Hb% was 14.3 g/dl with a PCV of 43.8%. The presence of both infections was confirmed by RT-PCR which amplified 225 bp and 354 bp products for dengue and chikungunya respectively. This was the first laboratory confirmed case of dengue and chikungunya co-infection, which was also the first confirmed report of chikungunya since 1969 in Sri Lanka. As clinical and biochemical manifestations of this patient suggested the probability of a mixed infection of dengue and chikungunya, the confirmation was achieved by a RT-PCR assay. This report highlights the importance of using molecular assays to confirm mixed viral infections during their early stages, especially infections such as dengue which can result in fatal complications.
Chloroquine resistant falciparum malaria among security forces personnel in the Northern Province of Sri Lanka
(Sri Lanka Medical Association, 2004) Hapuarachchi, H.A.C.; Dayanath, M.Y.D.; Abeysundara, S.; Bandara, K.B.A.T.; Abeyewickreme, W.; de Silva, N.R.
OBJECTIVE: To determine the occurrence and species distribution of malaria and the extent of chloroquine resistance among security forcespersonnel in a selected region of the Northern Province of Sri Lanka. DESIGN: A descriptive study. SETTING: Mannar District in the Northern Province. METHODS: Nine hundred and seventy five security personnel were screened for malaria by microscopy. Those who were positive were treated withchloroquine and were subjected to 28 day in vivo assay to determine chloroquine resistance. In vitro microtest assay was performed to determine the response of Plasmodium falciparum isolates to chloroquine in vitro. RESULTS: Of the 975 personnel screened, 181 (18.6%) were positive for malaria. P. falciparum was the predominant species (n = 125; 69.1%). The rest were due to P. vivax (n = 42; 23.2%) and mixed infections (n = 14; 7.7%). This was an inversion of the usual species distribution pattern in the country. In vivo assay revealed 38 (53.5%) P. falciparum infections as chloroquine resistant. Fifteen of 23 (65.2%) P. falciparum isolates showed evidence of resistance in vitro. None of the P. vivax infections showed evidence of chloroquine resistance. There was no significant difference in the severity of clinical disease between chloroquine resistant and sensitive infections at first presentation. Recrudescent P. falciparum infections had significantly lower mean parasite densities as well as lower clinical scores at recrudescence than at first presentation. CONCLUSION: Results demonstrate the high prevalence of malaria and chloroquine resistance in the study area and explains several contributory factors for this. There is an urgent need to review antimalarial drug policies in Sri Lanka
Comparison of five DNA extraction methods from human blood for the detection of Wuchereria bancrofti by polymerase chain reaction assays
(Sri Lanka Association for the Advancement of Science, 2008) Wijegunawardana, N.D.A.D.; Gunawardene, Y.I.N.S.; Manamperi, A.; Hapuarachchi, H.A.C.; Gunawardena, N.K.; Abeysundara, S.; Abeyewickreme, W.
Introduction: Lymphatic filariasis (Lf) is the second most common vector-borne disease globally. Approximately 90% of global burden of Lf is caused by Wuchereria bancrofti. W. bancrofti is routinely diagnosed by morphological identification of microfilariae (Mf) by microscopy which is a labour intense, low sensitive and time consuming method. Detection of W. bancrofti Deoxyribonucleic acid (DNA) using polymerase chain reaction (PCR) technique has become popular today, because of its high sensitivity and specificity. The overall success of the PCR strategy in detecting a filarial parasite in human blood varies between sample preparation methods. The objective of this study was to compare five DNA extraction methods (Lysis + centrifugation, Chelex method, Mf pellet method, Q1Aamp DNA Mini Kit commercial system, and Phenol-chloroform) with regard to duration of completion, labor involvement and PCR analytical sensitivity in-relation to DNA quality and quantity for the detection of W. bancrofti in human blood. Five blood samples positive for mf of W. bancrofti were tested for each DNA extraction method and were compared with respect to the sensitivity, time and quality/quantity of DNA and also by PCR analysis. Of the 5 methods tested, Mf pellet method was found to be the most simple and effective technique for the isolation of W. bancrofti Mf in human blood. This method was quick (15 min to complete), simple (5 min of manual labor), and very economical. It does not require any organic solvents, and the entire extraction procedure uses only two steps requiring supernatant transfer between tubes, hence minimizing the possibility of cross-contamination. Moreover, the PCR analytical sensitivity of the Mf pellet method was comparable to that of the commercial kit used. No PCR inhibitors were detected, independently of Mf count in the blood. Same method (optimal DNA extraction method) can be also used for the detection of parasite DNA from the field collected Mf positive mosquitoes using a PCR. Therefore, we recommend the Mf pellet method for processing large numbers of blood samples in community surveys aimed at determining the prevalence of W. bancrofti infection.
Evidence for emerging sulfadoxine-pyrimethamine resistance of Plasmodium falciparum isolated in the Northern Province of Sri Lanka
(Sri Lanka Association for the Advancement of Science, 2005) Hapuarachchi, H.A.C.; Dayanath, M.Y.D.; Abeysundara, S.; Bandara, K.B.A.T.; Abeyewickreme, W.; de Silva, N.R.
Genetic evidence of emerging sulfadoxine-pyrimethamine resistance of Plassmodium falciparum isolates in an operational area in the Northern Province of Sri Lanka
(Sri Lanka Association for the Advancement of Science, 2004) Hapuarachchi, H.A.C.; Dayanath, M.Y.D.; Abeysundara, S.; Bandara, K.B.A.T.; Abeyewickreme, W.; de Silva, N.R.
Geographical Information System (GIS)-based maps for monitoring of entomological risk factors affecting transmission of Chikungunya in Sri Lanka
(Faculty of Tropical Medicine, Mahidol University, 2008) Hapugoda, M.D.; Gunawardena, N.K.; Kusumawathie, P.H.D.; Jayasooriya, G.A.J.S.K.; Hapuarachchi, H.A.C.; Abeyewickreme, W.
INTRODUCTION: Chikungunya is an important mosquito-born viral infection in Sri Lanka at present. OBJECTIVE: To prepare OUS-based maps Tor monitoring of entomological risk Factors affecting transmission of chikungunya. RESEARCH DESIGN: Entomological risk factors affecting transmission of chikungunya were examined in a chikungunya hot-spot in the District of Kandy, Sri Lanka from April to July in 2008. Hundred house-holds in 33 clusters were recruited. The distant between clusters was at least 200m which is beyond the maximum flight range of Aedes mosquitoes, the vectors of chikungunya. Monthly surveillance was conducted using standard entomological surveillance methods followed by obtaining information through a pre-tested questionnaire. G1S was used to map the selected house¬holds and display entomological data. RESULTS: GIS-based maps were developed to highlight the spatial and temporal distribution of vectors, their density and the presence of key breeding sites. Maps showed the presence of high density of Aedes albopictus mosquitoes in more than 90% of the key (artificial) breeding habitats in all clusters throughout the study period. DISCUSSION: Generalized high density of Ae. albopictus suggests that this species may play a major role in transmitting chikungunya in the study area. GIS-based 'maps may be used as an important tool to find out spatial and temporal distribution of vectors, their density and key breading sites in a selected hotspot, which would enable cost effective and efficient interventions for vector control in disease endemic areas.
Intestinal parasites and the growth status of internally displaced children in Sri Lanka
(Sage Publishing, 2007) Chandrasena, T.G.A.N.; Hapuarachchi, H.A.C.; Dayanath, M.Y.D.; Pathmeswaran, A.; de Silva, N.R.
The growth status and intestinal parasitic infections among a group of children displaced by war in Sri Lanka was investigated. There was a high prevalence of growth retardation (wasting, stunting and underweight being 41 percent, 28percent and 69.9 percent, respectively) and intestinal parasitic infections (40.2 percent) among the study population. Provision of adequate food, purified drinking water, sanitation and broad-spectrum anthelmintics is recommended.
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.
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.
Island-wide diversity in single nucleotide polymorphisms of the Plasmodium vivax dihydrofolate reductase and dihydropteroate synthetase genes in Sri Lanka
(BioMed Central, 2007) Schousboe, M.L.; Rajakaruna, R.S.; Salanti, A.; Hapuarachchi, H.A.C.; Galappaththi, G.N.; Bygbjerg, I.C.; Amerasinghe, P.H.; Konradsen, F.; Alifrangis, M.
BACKGROUND: Single nucleotide polymorphisms (SNPs) in the Plasmodium vivax dihydrofolate reductase (Pfdhfr) and dihydropteroate synthetase(Pvdhps) genes cause parasite resistance to the antifolate drug combination, sulphadoxine/pyrimethamine (SP). Monitoring these SNPs provide insights into the level of drug pressure caused by SP use and presumably other antifolate drugs. In Sri Lanka, chloroquine (CQ) with primaquine (PQ) and SP with PQ is used as first and second line treatment, respectively, against uncomplicated Plasmodium falciparum and/or P. vivax infections. CQ/PQ is still efficacious against P. vivax infections, thus SP is rarely used and it is assumed that the prevalence of SNPs related to P. vivax SP resistance is low. However, this has not been assessed in Sri Lanka as in most other parts of Asia. This study describes the prevalence and distribution of SNPs related to P. vivax SP resistance across Sri Lanka. SUBJECTS AND METHODS: P. vivax-positive samples were collected from subjects presenting at government health facilities across nine of the major malaria endemic districts on the island. The samples were analysed for SNPs/haplotypes at codon 57, 58, 61 and 117 of the Pvdhfr gene and 383, 553 and 585 of the Pvdhps gene by applying PCR followed by a hybridization step using sequence specific oligonucleotide probes (SSOPs) in an ELISA format. RESULTS: In the study period, the government of Sri Lanka recorded 2,149 P. vivax cases from the nine districts out of which, 454 (21.1%) blood samples were obtained. Pvdhfr haplotypes could be constructed for 373 of these. The FSTS wild-haplotype was represented in 257 samples (68.9%), the double mutant LRTS haplotype was the most frequently observed mutant (24.4%) while the triple mutation (LRTN) was only identified once. Except for two samples of the single mutated Pvdhps GAV haplotype, the remaining samples were wildtype. Geographical differences were apparent, notably a significantly higher frequency of mutant Pvdhfr haplotypes was observed in the Northern districts. CONCLUSION: Since SP is rarely used in Sri Lanka, the high frequency and diversity of Pvdhfr mutations was unexpected indicating the emergence of drug resistant parasites despite a low level of SP drug pressure.
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 06/028
Laboratory confirmation of dengue and chikungunya co-infection
(Sri Lanka Medical Association, 2008) Hapuarachchi, H.A.C.; Bandara, K.B.A.T.; Hapugoda, M.D.; Williams, S.; Abeyewickreme, W.
No Abstract Available
Large-scale entomological assessment of Wuchereria bancrofti transmission by dissection and PCR-ELISA in Gampaha district, Sri Lanka
(Sri Lanka Association for the Advancement of Science, 2008) Wijegunawardana, N.D.A.D.; Gunawardene, Y.I.N.S.; Manamperi, A.; Hapuarachchi, H.A.C.; Bandara, K.B.A.T.; Abeyewickreme, W.
Entomological surveys are important tools for monitoring progress of lymphatic filariasis (Lf) eradication programs. In this study, dissection of Culex quinquefasciatus was compared with a Polymerase Chain Reaction - Enzyme Linked Immunosorbent Assay (PCR-ELISA) for pooled mosquitoes to assess filarial infection levels in the major vector of Wuchereria bancrofti in Gampaha district, following mass-treatment programme with diethylcarbamazine (DEC) and albendazole. Mosquitoes were collected in 30 sentinel and 15 non-sentinel sites in 15 Medical Officer of Health (MOH) areas of Gampaha district known for the presence of W. bancrofti transmission. Captured mosquitoes were dissected to determine the W. bancrofti larvae (L1, L2, L3). PCR was carried out using Deoxyribonucleic acid (DNA) extracted from mosquito pools (15 body parts/pool) utilizing primers specific for the Wb-SspI repeat. PCR products were analyzed by hybridization ELISA using fluorescein-labeled wild type specific probes. The prevalence of infected/infective mosquitoes in PCR pools (3pools/site) was estimated using the PoolScreenTM algorithm and a novel probability-based method. The prevalence of infected mosquitoes with L1-L2 larvae of W. bancrofti ranged from 0%-8.54% by dissection and point estimates of infection prevalence as assayed by PCR-ELISA, ranged from 0% - 25.4%. Mosquitoes collected from all MOH areas (80%, N = 12), except for Minuwangoda, Dompe and Ragama, were positive for W. bancrofti larvae, with a prevalence rate ranging from 0.78% to 16.97% in both methods. Of 30 sentinel sites, 43.3% (N = 13) were positive for W. bancrofti transmission whereas it was evident in 40% (N = 6) of non-sentinel sites. The proportion of positive pools detected by the PCR-ELISA assay was higher than that obtained by the dissection indicating that PCR-ELISA assay is more sensitive than the dissection method in detecting infected/infective mosquitoes. Also results of this study showed that autochthonous transmission of W. bancrofti continues in the Gampaha district despite completion of the 5 year mass drug administration (MDA) programme. Therefore, we emphasize the use of more sensitive tools such as PCR-ELISA to monitor the impact of the MDA programme on disease transmission. This study also emphasizes that control measures should be further continued until the microfilareamic population is reduced to a level which could interrupt transmission in the area. Financial assistance received from WHO/SEARO/TDR (grant no. SN 1152) and University of Kelaniya (Grant no. RP/03/04/06/01/2006) is acknowledged
A Mixed infection of Plasmodium falciparum and Plasmodium malariae: the first report of a Plasmodium malariae infection after 37 years of its absence in Sri Lanka
(2008) Hapuarachchi, H.A.C.; Abeysundara, S.; Gunawardena, N.K.; Manamperi, A.; Senevirathne, M. P.; Leemingsawat, S.; Chavalitshewinkoon-petmitr, P.; de Silva, N.R.; Abeyewickreme, W.
Malaria has been endemic in Sti Lanka for several centuries. Currently, only Plasmodium falciparum and P. vivax are present in the country. P. malariae infections have not .been reported in Sri Lanka since 1969. The objective is to determine the presence of malaria species in a patient returned from Malawi. The clinical history of intermittent high fever for 2 weeks accompanied by severe headache, myalgia, arthralgia, vomitimg, loss of appetite and backache with ictetus and mild hepatosplenomegaly suggested malaria in this 51 year old patient. Apart from the basic biochemical investigations, presence of malarial species was determined by light microscopy and confirmed by Real-Time Polymerase Chain Reaction (PCR) technology. Biochemical investigations showed a high serum bilirubin (4.8 mg/di) and liver enzyme (SGOT = >125 units, SGPT = >250 units) levels. Serum haemoglobin level (12.8 g%) was normal. Except for the presence of ptoteinuria (albumin = ++), bile (+) and red blood corpuscles (RBC) in his urine, renal functions were normal. Microscopical examination of Giemsa stained thin and thick blood smears showed an asexual parasite density of 120,000 per ul of blood. Infected RBCs were not enlarged, The presence of double-chromatin and applique form trophozoites, occasionally invading multiple RBCs suggested P. falciparum infection. In addition, there were characteristic band form trophozoites of P. malariae. Real-Time PCR protocol confirmed the presence of both P. falciparum and P. malariae in this patient. This is the first case of P. malariae reported in Sri Lanka after 4 decades, though the infection had been acquired from Malawi. Clinical and biochemical evidence indicated liver dysfunction and a transient glomerulonephritis, both of which subsided after treatment with quinine. This case report emphasizes the need of physicians to be more vigilant about the presence of malaria among immigrants, despite the drastic reduction of malaria in the country in recent years. Hence, this report highlights the importance of a proper programme in Sri Lanka to screen immigrants for infectious diseases.
Molecular Diagnosis for confirmation of Infectious Diseases in Sri Lanka in 2009
(Sri Lanka Association for the Advancement of Science, 2009) Hapugoda, M.D.; Bandara, K.B.A.T.; Dayanath, M.Y.D.; Wellawaththage, C.; Hapuarachchi, H.A.C.; Abeyewickreme, W.
Confirmation of infectious disease outbreaks in Sri Lanka is an important national requirement. Many clinicians as well as general practitioners find it difficult to confirm diagnosis of some infectious diseases only on clinical grounds. Molecular assays can rapidly confirm diagnosis at the early phase of diseases when aetiological agents are present and before antibody titers are at detectable levels. PCR-based assays are more sensitive and more specific than all conventional methods. Overall objective of this study was early, rapid and definitive laboratory confirmation of the aetiology of chikungunya, dengue, Japanese Encephalitis (JE), leishmaniasis, leptospirosis, malaria and West Nile Virus (WNV) through molecular assays. A rapid mobile investigation team equipped with the case definition, questionnaires, sample collection methods and diagnostic methods for each disease was established. This group visited outbreak areas and collected clinical and laboratory information and clinical samples from suspected patients at the early stage of symptoms: 1-5 days. Clinical samples were laboratory tested by disease specific molecular assays (PCR/RT-PCR). Clinical parameters of each disease were analyzed. Only chikungunya, dengue and leptospirosis outbreaks out of the above mentioned diseases were reported during the preceding six months in 2009. The team collected blood samples from clinically suspected cases of chikungunya (n=430), dengue (n=116) and leptospirosis (n=23) from different parts of the island. Molecular assays confirmed infections only in 81% (350/430) for chikungunya, 7% (8/116) for dengue and 9% (2/23) for leptospirosis in selected suspected patients. Reports of the confirmation of the disease outbreak by molecular assay were sent to the relevant health authority within two days to highlight the magnitude of the infection. These results showed importance of aetiological confirmation of infectious diseases by molecular assays. In conclusion, molecular diagnosis using a single clinical sample is important for rapid, definitive and early confirmation of aetiology of a particular infectious disease outbreak when serological methods are of little value at the early stage of infection. This is important for cost effective and efficient control of the outbreaks through proper clinical management.
Molecular markers of chloroquine resistance in Plasmodium falciparum in Sri Lanka:frequency before revision of the antimalarial drug policy
(Academic Press, 2009) Hapuarachchi, H.A.C.; Abeysundara, S.; Dayanath, M.Y.D.; Manamperi, A.; Abeyewickreme, W.; de Silva, N.R.
No Abstract Available
Night blood survey of a selected high-risk population for lymphatic filariasis
(Sri Lanka Association for the Advancement of Science, 2007) Wijegunawardana, N.D.A.D.; Gunawardene, Y.I.N.S.; Abeyewickreme, W.; Gunawardena, N.K.; Hapuarachchi, H.A.C.; Abeysundara, S.
Human infection with Wuchereria bancrofti causes a disabling parasitic disease known as lymphatic filariasis, which is a major public health and socio-economic problem in many parts of the world. Little is known about the prevalence of filariasis among high-risk populations for filariasis. Objective of this study was to determine such prevalence of lymphatic filariasis among Mahara prison inmates whom the Anti Filaria Campaign (AFC) has identified as a high-risk group. All inmates of Mahara Prison were screened for Microfilariae (Mf) except those in special cells, by night blood film microscopy to determine the prevalence of infection from February to May 2007. All inmates were males of greater than 15 years. Of the 423 inmates screened, 15 were positive for Mf, giving a Mf positive rate of 3.55% in the study population and a mean Mf density of 5 Mf/60 æl blood, ranging between 4 to 9.2 Mf /60 æl of blood with a standard deviation of 2.49. The highest number of infected inmates was residents of Colombo and Gampaha districts where transmission is currently taking place. This is one of the few studies undertaken to date to determine the prevalence of bancroftian filariasis among inmates of a prison, a neglected population in Sri Lanka. This study indicates that the Mf rate of bancroftian filariasis in this study population is far greater than the 0.18% currently reported in the country. Therefore, an intensive programme is recommended to contain the spread of infection within this study population. For this, a proper screening programme combined with antifilarial treatment and vector control programme is urgently required. Acknowledgements: Authors wish to acknowledge the financial assistance received from WHO/SEARO/TDR (grant no. SN 1152) and University of Kelaniya (Research grant no. RP/03/04/06/01/2006). Authors wish to thank Dr. Ravi Mudaliage, Senior Medical Officer, Prison's Hospital, Mahara, Ragama for his support and encouragement during field study activities. Authors also wish to thank Mr. M. Y. D. Dayanath, Ms. N.M. Ashoka Malanie, Mr. M.I.M.Peris, Mr. Y.L.Rassapana and other staff members of the Molecular Medicine Unit and Department of Parasitology, Faculty of Medicne, University of Kelaniya, Ragama for their assistance
Point mutations in the dihydrofolate reductase and dihydropteroate synthase genes of Plasmodium falciparum and resistance to sulfadoxine-pyrimethamine in Sri Lanka
(American Society of Tropical Medicine and Hygiene, 2006) Hapuarachchi, H.A.C.; Dayanath, M.Y.D.; Bandara, K.B.A.T.; Abeysundara, S.; Abeyewickreme, W.; de Silva, N.R.; Hunt, S.Y.; Sibley, C.H.
Sulfadoxine-pyrimethamine (SP) is the second-line treatment for Plasmodium falciparum malaria in Sri Lanka. Resistance to SP is caused by point mutations in the dihydrofolate reductase (Pf-dhfr) and dihydropteroate synthase (Pf-dhps) genes of P. falciparum. We determined the genotype of Pf-dhfr and Pf-dhps and the clinical response to SP in 30 field isolates of P. falciparum from Sri Lanka. All patients treated with SP had an adequate clinical response. Eighty-five percent (23 of 27) of pure field isolates carried parasites with double mutant alleles of Pf-dhfr (C59R + S108N) and showed about 200-fold higher levels of resistance to pyrimethamine than the wild type in a yeast system. None of the isolates had either known or novel mutations at other positions in the dhfr domain. In contrast, 67% (20 of 30) of the isolates carried parasites that were wild type for Pf-dhps. In Sri Lanka, detection of the triple mutant allele of Pf-dhfr will require tracking mutations at codon 51
Population data for CSF1PO, TPOX, THO1, D16S539, D7S820, D13S317, FESFPS, vWA and F13B short tandem repeat (STR) polymorphisms in Sri Lanka
(Sri Lanka Association for the Advancement of Science, 2004) Manamperi, A.; Gunawardene, Y.I.N.S.; Bandara, K.B.A.T.; Dayanath, M.Y.D.; Hapuarachchi, H.A.C.; Abeyewickreme, W.