Journal/Magazine Articles
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This collection contains original research articles, review articles and case reports published in local and international peer reviewed journals by the staff members of the Faculty of Medicine
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Item Distribution and seasonal variation of malaria vectors in the Mannar and Jaffna Districts; an entomological investigation during the phase of prevention of re-establishment of malaria in Sri Lanka(Springer Link, 2024) Jude, J.; Gunathilaka, N.; Wijerathna, T.; Fernando, D.; Wickremasinghe, R.; Abeyewickreme, W.Sri Lanka has been declared “malaria-free” since 2016. The presence vectors and the cent establishment of new vectors are key challenges. This study documents the distribution of malaria vectors in previously high malaria endemic areas in Sri Lanka. Three locations were selected in Mannar and Jaffna districts. Entomological surveillance was carried out during January 2019 to January 2020 in both districts using cattle baited net (CBNT), hand collection (HC), and larval collection. The variation of mosquito abundance with selected climatic variables were evaluated using Pearson’s correlation. A total of 44,526 anophelines belonging to 12 species was encountered from both districts. The CBNT was the most productive technique that represented 78.65% (n = 35,022) of the total collection. Anopheles subpictus was the predominant species among adult collections in both districts, while in larval surveys, An. stephensi (60.1%; n = 2963) and An. varuna (40.9%; n = 1026) were observed in Jaffna and Mannar districts, respectively. The adult density indicated significantly strong positive correlations to the rainfall (r = 0.619, P < 0.05) and humidity (r = 0.524, P < 0.05) in both Jaffna and Mannar (rainfall: r = 0.553, P < 0.05; humidity: r = 0.553, P < 0.05). The number of larvae was not directly correlated with climatic variables. The present study reports the presence of An. culicifacies, An. subpictus and An. stephensi. Considering the fact that imported malaria cases are reported across the country the fact that there is an entomological risk to transmit malaria locally is a challenge. This warrants the continuous monitoring of vector population and seasonal variation, especially in previous malaria endemic regions.Item Malaria control, elimination, and prevention as components of health security: A review(American Society of Tropical Medicine and Hygiene, 2022) Perera, R.; Wickremasinghe, R.; Newby, G.; Caldera, A.; Fernando, D.; Mendis, K.International travel, a major risk factor for imported malaria, has emerged as an important challenge in sustaining malaria elimination and prevention of its reestablishment. To make travel and trade safe, the WHO adopted the International Health Regulations (IHR) which provides a legal framework for the prevention, detection, and containment of public health risks at source. We conducted a systematic review to assess the relevance and the extent of implementation of IHR practices that can play a role in reducing malaria transmission. Selected studies addressed control, elimination, and prevention of reestablishment of malaria. Study themes focused on appraisal of surveillance and response, updating national policies to facilitate malaria control and elimination, travel as a risk factor for malaria and risk mitigation methods, vector control, transfusion malaria, competing interests, malaria in border areas, and other challenges posed by emerging communicable diseases on malaria control and elimination efforts. Review results indicate that malaria has not been prioritized as part of the IHR nor has the IHR focused on vector-borne diseases such as malaria. The IHR framework in its current format can be applied to malaria and other vector-borne diseases to strengthen surveillance and response, overcome challenges at borders, and improve data sharing-especially among countries moving toward elimination-but additional guidelines are required. Application of the IHR in countries in the malaria control phase may not be effective until the disease burden is brought down to elimination levels. Considering existing global elimination goals, the application of IHR for malaria should be urgently reviewed and included as part of the IHR.Item Use of cyclopoid copepods for control of Anopheles (Diptera: Culicidae) mosquito larvae to prevent re-emergence of malaria in Sri Lanka(Malaria Research Centre, Indian Council of Medical Research, 2019) Ranathunge, T.; Abeyewickreme, W.; Iqbal, M. C. M.; Hapugoda, M.BACKGROUND & OBJECTIVES: Although malaria is eliminated from Sri Lanka, there is a possible risk of spread from infected persons coming from malaria endemic countries. The presence of major and potential vectors in several parts of the country along with drug resistance, necessitates the identification of effective and novel control methods. The present study focused on identifying effective biological control agents for anopheline larvae using carnivorous copepods under laboratory and field conditions to prevent re-introduction of malaria in the country. METHODS: Three copepod species, namely Mesocyclops scrassus, Cyclops varicans and C. languides collected from different areas in the country were cultured by adding supplementary food, and their predatory efficacy was evaluated under laboratory and field conditions. RESULTS: Significant variation (p <0.05) was observed in predation rates of studied copepod species. The species M. scrassus showed the highest predacious efficiency, and consumed the highest number of anopheline larvae under laboratory and field conditions. Further, M. scrassus had higher survival rate than C. varicans and C. languides. INTERPRETATION & CONCLUSION: The results of the study suggest that the predatory copepod M. scrassus can be used as a bio-control agent for the control of Anopheles mosquitoes to prevent re-emergence of malaria in the country. Additional research is suggested to identify naturally available copepod species and their predatory efficacy. KEYWORDS: Anopheles; Sri Lanka; biological control; copepods; malaria vectors; predatory efficacy.Item Role of a dedicated support group in retaining malaria-free status of Sri Lanka.(New Delhi : National Institute of Malaria Research, 2019) Datta, R.; Mendis, K.; Wickremasinghe, R.; Premaratne, R.; Fernando, D.; Parry, J.; Rolfe, B.No Abstract AvailableItem Effectiveness of passive case detection for imported malaria in a hospital setting in Sri Lanka during the prevention of re-introduction phase of malaria(Oxford University Press, 2019) Dharmawardena, P.; Premaratna, R.; Mendis, K.; Wickremasinghe, A.R.; Rodrigo, C.; Harintheran, A.; Fernando, D.INTRODUCTION: The effectiveness of the passive case detection (PCD) system for imported malaria was assessed in government hospitals in Sri Lanka post-elimination of malaria. METHODS: In 18 medical wards (test wards) in four government hospitals, the referral for malaria testing and the diagnosis of malaria by the ward physicians were monitored. Concurrently, in-ward febrile patients were assessed independently for their eligibility for referral for malaria diagnosis and were tested for malaria. The malaria incidence in 16 other wards (control wards), which the study did not screen, served as controls. RESULTS: Four imported malaria patients were diagnosed within the PCD system among 25 874 febrile patients admitted during the 14-month study period, two of whom were diagnosed in the test wards and two in the control wards. The study's screening programme did not detect any more malaria patients than detected by the routine PCD system of the wards. However, far fewer patients were screened for malaria (1.3%) than were eligible for screening (29.4%), and some infections were detected incidentally, rather than by a request for a malaria test. CONCLUSION: A continuous effort to maintain awareness of the disease among physicians would be required if the PCD system is to be effective for the detection of imported malaria, post-elimination.Item Composition of malaria vectors and diversity of anopheline breeding habitats in the district of Mannar, Sri Lanka(Central Environmental Authority (CEA), 2016) Gunathilaka, P.A.D.H.N.; Hapugoda, M.D.; Wickremasinghe, A.R.; Abeyewickreme, W.In the malaria elimination phase in Sri Lanka, investigation on biological and ecological factors of malaria vectors are important in planning appropriate vector controlling strategies. Lack of sufficient biological and ecological information on malaria vectors in the Northern Province of the country, a malaria endemic region, is a major constrain in successful implementation of malaria control programmes. Therefore, the objective of this study was to explore the diversity of breeding habitats and species composition of malaria vector mosquitoes in the District of Mannar, Sri Lanka. Potential habitats for Anopheles mosquito larvae were surveyed from June, 2010 to July 20 J2 on a monthly basis in selected sampling sites in the Mannar District: Mannar Town, Vankalai and Silawathiura, within a radius about 20 km. In each site, 4 sub sites were selected A total of 37,788 Anopheles representing ten species was recorded from 12 breeding habitat categories. Built wells and waste water collections were conducive for anopheline breeding. Anopheles subpictus (96.2%, n= 36,351) was the dominant species followed by An. peditaeniatus (1.47%, n= 557), An. barbirostris (1.23%, n= 463), An. nigerriums (0.75%,n = 285), An. varuna (0.19%, n= 74), An. barbumbrosus (0.1%, n= 38), An. vagus' (0.03%, n= 12), An. pallidus (0.01%, n= 4), An.jamesii (0.05%, n= 2) and An. pseudojamesi (0.05%, n= 2). Use of wells and waste water drains as breeding places by potential malaria vectors indicates that both of these habitats act as larval reservoirs during the dry season. Presence of theses habitats in close proximity to human habitats create a potential risk of malaria transmission among humans. Therefore, health authorities need to be vigilant on these new habitats in vector control programmes.Item 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 AvailableItem An Indigenous case of Plasmodium ovale infection in Sri Lanka(American Society of Tropical Medicine and Hygiene, 2008) Wickremasinghe, R.; Galappaththi, G.N.; Fernando, W.A.; de Monbrison, F.; Wijesinghe, R.S.; Mendis, K.N.; Picot, S.; Ringwald, P.; Wickremasinghe, A.R.Plasmodium ovale, which is generally prevalent only in the African region, has been emerging in the Asian and southeast Asian regions. It has not been reported in Sri Lanka. We report, to our knowledge, an indigenous case of P. ovale infection in Sri Lanka. This patient, who was diagnosed by a polymerase chain reaction, had no history of travel overseas or receipt of a transfusion of blood or any blood products, which makes this a likely caseof indigenous transmission. This incidental finding of a P. ovale infection has implications for malaria control in the country and highlights the need to rigorously monitor malaria incidence, as well as prevalent Plasmodium species, with newer and more reliable diagnostics.Item Genotyping of Plasmodium vivax infections in Sri Lanka using Pvmsp-3 alpha and Pvcs genes as markers:a preliminary report(Malaysian Society of Parasitology and Tropical Medicine, 2008) Manamperi, A.; Sanath, M.; Fernando, D.; Wickremasinghe, R.; Anura, B.; Hapuarachchi, C.; Abeyewickreme, W.; Wickremasinghe, A.R.Plasmodim vivax malaria accounts for more than 90% of malaria cases in Sri Lanka. There is limited information on the genetic heterogeneity of P. vivax in endemic areas of the country. Here we have assessed the potential of two P. vivax genes as genetic markers for their use in genotyping parasites collected from the field. DNA extracted from Geimsa-stained P. vivax positive slides were genotyped at two polymorphic loci: the P. vivax merozoite surface protein 3- alpha (Pvmsp-3alpha) and circumsporozoite protein (Pvcs). Analysis of these two genetic markers revealed 11 distinguishable variant types from the two genetic markers: 4 for Pvcs and 7 for Pvmsp-3alpha. The results indicate that the P. vivax parasite population is highly diverse in Sri Lanka, despite the low level of transmission.Item 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.