Medicine
Permanent URI for this communityhttp://repository.kln.ac.lk/handle/123456789/12
This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty
Browse
47 results
Search Results
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 Awareness on Malaria among Public and Healthcare Providers during the Prevention of Re-Introduction Phase in Sri Lanka(Sri Lanka Medical Association, 2020) Hamsananthy, J.; Wickremasinghe, A.R.INTRODUCTION AND OBJECTIVES: Prevention of re-introduction/re-establishment of malaria is a challenge for Sri Lanka due to high receptivity and vulnerability. Imported cases are being reported and an introduced case was reported in 2018. The objective of this study was to assess the awareness on malaria among public and healthcare providers which is essential during the prevention of re-introduction/re-establishment phase. METHODOLOGY: Two national surveys were conducted among 3454 households and 766 healthcare providers in 2016. Household survey was conducted using a multistage cluster sampling method. Healthcare providers’ survey used stratified random sampling and a self-administered questionnaire. RESULTS: The mean awareness score of healthcare providers was 54.7% (SD=10.6). Although 99.1% of healthcare providers (n=759) identified fever as a symptom of malaria, the majority (n=634) had not seen, diagnosed or treated a malaria case during the last 5 years. The mean awareness score of heads of households was 28.6 % (SD = 9.03). 74.4% of heads of households (n=2570) had ever seen/heard messages about malaria; 7.2% (n=249) had seen/heard in the past 6 months. The common media of communication were television (n=2714, 78.6%) and mobile phones (n=2242, 64.9%). The majority knew that malaria is spread by a mosquito bite (92.7%, n=3202) and fever (71.8% n=2479) is a symptom of malaria. CONCLUSIONS: The majority of healthcare providers have not seen a case of malaria; updates on malaria should be regularly given to suspect malaria in the differential diagnosis of fever. Television and mobile phone technology can be used to increase awareness on malaria among the general public.Item The first case of introduced malaria in Sri Lanka after elimination: Approach by the Anti Malaria Campaign to prevent re-establishment of malaria(Sri Lanka Medical Association., 2019) Karunasena, V.M.; Marasinghe, M.M.M.B.; Amarasinghe, S.; Senaratne, P.A.S.; Hasantha, M.B.R.; Hevawitharana, M.INTRODUCTION & OBJECTIVES: Apart from imported malaria infections Sri Lanka has been free of malaria cases for the past six years after elimination until December 26th 2018, when the first introduced case was reported. This manuscript describes the probable index case and the introduced case of malaria, and actions taken to curtail the spread of transmission. METHODS: Detailed case investigations of the probable index and introduced cases were carried out and appropriate responses were mounted by the Anti Malaria Campaign (AMC). Genome sequencing was performed on parasites obtained from the two cases to determine relatedness of the two parasite isolates. RESULTS: An Indian employed at a construction site in Moneragala district, developed a Plasmodium vivax infection 23 days after arriving in Sri Lanka. Thirteen days later a Sri Lankan with no travel history to a malaria endemic country was diagnosed with P.vivax malaria following his visit to the same site. Multi-locus genome sequencing show that P. vivax strains obtained from these cases share 100% genetic identity at five loci of three polymorphic genes (CSP, MSPI and MSP3a genes), suggesting that both patients were infected with the same P.vivax strain. AMC mounted a rapid response including parasitological and entomological surveillance, active case detection, appropriate vector control measures and raising public and clinician awareness at relevant sites. CONCLUSION: An outbreak and the re-introduction of malaria to Sri Lanka from an index and introduced cases were prevented by prompt interventions which illustrate a very effective surveillance and response system.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 Importance of private health sector in malaria surveillance: a case study in Nuwara-Eliya district, Sri Lanka(Sri Lanka College of Microbiologists, 2002) Kusumawathie, P.H.D.; Wickremasinghe, A.R.; Karunaweera, N.OBJECTIVE: To determine the Utilization of public and private health facilities by suspected malaria cases in Divisional Director of Health Services (DDHS) area Hanguranketha in Nuwara-eliya district (from July 2000 to June 2001). DESIGN, SETTING AND METHODS: Two state hospitals, DH Rikillagaskada and RH Gonagantenna were selected as public health facilities. Seven clinics at Rikillagaskada and Gonagantenna in which government medical officers engaged in private practice after duty hours were selected as private health facilities. The number of cases blood filmed for malaria at public facilities was obtained from hospital records. Data for the private sector was obtained using a pre designed form. Reporting from the private sector was done on a monthly basis. RESULTS: Among 572 cases blood filmed at government hospitals, 22 were positive for P.vfvax. In the private sector. 634 cases of suspected malaria were reported and treated on clinical grounds. During the study period, 40 P.vivax and 65 P.falciparum cases were detected by examining 1270 blood films collected by Active Case Detection and Special Malaria Clinics, conducted in the villages with risk of malaria transmission within the study area. Of the microscopically confirmed malaria cases, 15.4% of P.falciparum infections were resistant to chloroquine. Investigation of malaria cases revealed 66.7% of cases were indigenous while 33.3% were imported. If the Slide Positive Rate (SPR) of the government facilities is applied to the data of the private sector, 610 cases would have been given chloroquine without actually having malaria. CONCLUSIONS: According to this study, 52.57% of suspected malaria cases had sought treatment at private health facilities. Incorporating the private health sector in malaria surveillance would be helpful in correct treatment and control of malaria in malarious areas. Unnecessary anti malarial therapy should be reduced by provision of laboratory facilities at private health centers. ACKNOWLEDGEMENTS: Assistance provided by the Provincial Director Health Services, Central Province and Deputy Provincial Director Health Services, Kandy, and the Director Anti-Malaria Campaign is acknowledged.Item Extrathymic T cells in human malaria patients(Elsevier, 1998) Watanabe, W.; Weerasinghe, A.; Miyaji, C.; Sekikawa, H.; de Silva, N.R.; Gunawardena, S.; Ratnayake, H.; Kobayashi, J.; Thoma, H.; Sato, Y.; Abo, T.