Journal/Magazine Articles
Permanent URI for this collectionhttp://repository.kln.ac.lk/handle/123456789/13
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
Browse
14 results
Search Results
Item First report of V1016G and S989P knockdown resistant (kdr) mutations in pyrethroid-resistant Sri Lankan Aedes aegypti mosquitoes(BioMed Central, 2018) Fernando, S.D.; Hapugoda, M.; Perera, R.; Saavedra-Rodriguez, K.; Black WC 4th; de Silva, N.K.; ; ;BACKGROUND: Dengue is a serious arboviral disease in Sri Lanka with a large number of dengue fever (DF) cases every year. Control of the primary vector Aedes aegypti depends upon larval habitat source reduction and insecticide application. However, increases in the number of reported cases suggest the inefficiency of current control strategies and the possibility of resistance to currently used insecticides. Early detection of mutations in the voltage-gated sodium channel (vgsc) gene that confer knockdown resistance (kdr) to pyrethroid insecticides is important in resistance management in vector populations. RESULTS: Resistance to pyrethroid insecticides was detected in the three populations studied. Polymerase chain reaction was used to detect the presence of two kdr mutations F1534C and V1016G. During this process a S989P mutation was also detected in pyrethroid-resistant Ae. aegypti populations. These mutations were found to be widespread and frequent in the collections studied. CONCLUSIONS: To our knowledge, this study reveals for the first time the presence of V1016G and S989P mutant alleles in the vgsc of Sri Lankan Ae. aegypti populations. The spread of the mutant alleles throughout the country poses a threat of increased resistance to pyrethroids. Long-term insecticide applications and indiscriminate use of pyrethroids has led to the evolution of resistance. More strategic and diverse strategies, including novel insecticides with new modes of action and community participation, should be engaged for Ae. aegypti control.Item Should chemoprophylaxis be a main strategy for preventing re-introduction of malaria in highly receptive areas? Sri Lanka a case in point(BioMed Central, 2017) Wickremasinghe, A.R.; Wickremasinghe, R.; Herath, H.D.B.; Fernando, S.D.BACKGROUND: Imported malaria cases continue to be reported in Sri Lanka, which was declared 'malaria-free' by the World Health Organization in September 2016. Chemoprophylaxis, a recommended strategy for malaria prevention for visitors travelling to malaria-endemic countries from Sri Lanka is available free of charge. The strategy of providing chemoprophylaxis to visitors to a neighbouring malaria-endemic country within the perspective of a country that has successfully eliminated malaria but is highly receptive was assessed, taking Sri Lanka as a case in point. METHODS: The risk of a Sri Lankan national acquiring malaria during a visit to India, a malaria-endemic country, was calculated for the period 2008-2013. The cost of providing prophylaxis for Sri Lankan nationals travelling to India for 1, 2 and 4 weeks was estimated for that same period. RESULTS: The risk of a Sri Lankan traveller to India acquiring malaria ranged from 5.25 per 100,000 travellers in 2012 to 13.45 per 100,000 travellers in 2010. If 50% of cases were missed by the Sri Lankan healthcare system, then the risk of acquiring malaria in India among returning Sri Lankans would double. The 95% confidence intervals for both risks are small. As chloroquine is the chemoprophylactic drug recommended for travellers to India by the Anti Malaria Campaign of Sri Lanka, the costs of chemoprophylaxis for travellers for a 1-, 2- and 4-weeks stay in India on average are US$ 41,604, 48,538 and 62,407, respectively. If all Sri Lankan travellers to India are provided with chemoprophylaxis for four weeks, it will comprise 0.65% of the national malaria control programme budget. CONCLUSIONS: Based on the low risk of acquiring malaria among Sri Lankan travellers returning from India and the high receptivity in previously malarious areas of the country, chemoprophylaxis should not be considered a major strategy in the prevention of re-introduction. In areas with high receptivity, universal access to quality-assured diagnosis and treatment cannot be compromised at whatever cost.Item The need for preventive and curative services for malaria when the military is deployed in endemic overseas territories: a case study and lessons learned(BioMed Central, 2017) Fernando, S.D.; Booso, R.; Dharmawardena, P.; Harintheran, A.; Raviraj, K.; Rodrigo., C.; Danansuriya, M.; Wickremasinghe, A.R.BACKGROUND: Sri Lanka has been free from indigenous malaria since November 2012 and received the WHO certificate for malaria-free status in September 2016. Due to increased global travel, imported malaria cases continue to be reported in the country. Military personnel returning home from international peace-keeping missions in malaria endemic countries represent a key risk group in terms of imported malaria. The present study intended to characterize the potential causes of a malaria outbreak among the Sri Lankan security forces personnel deployed in the Central African Republic (CAR). METHODS: Data were collected from a cross-sectional survey distributed among Sri Lankan Air Force personnel who had returned from United Nations peace-keeping missions in the CAR region. A pre-tested questionnaire was used for the data collection, and focus group discussions were also conducted. RESULTS: One hundred twenty male Air Force personnel were interviewed (out of a group of 122 officers and airmen). All participants were deployed in the CAR for 14 months and were aware of the existence of chemoprophylaxis against malaria. The majority of the subjects (92.5%, 111/120) also knew that prophylaxis should be started prior to departure. However, the regular use of chemoprophylaxis was reported by only 61.7% (74/120) of the sample. Overall, 30.8% of the participants (37/120) had 44 symptomatic episodes of malaria during deployment, and one person succumbed to severe malaria. All cases were associated with noncompliance with chemoprophylaxis. CONCLUSION: Better coordination with overseas healthcare services and the establishment of directly observed chemoprophylaxis may help to avoid similar outbreaks in the future.Item Contribution of the private sector healthcare service providers to malaria diagnosis in a prevention of re-introduction setting(BioMed Central, 2016) Fernando, S.D.; Dharmawardena, P.; Epasinghe, G.; Senanayake, N.; Rodrigo, C.; Premaratna, R.; Wickremasinghe, R.BACKGROUND: Sri Lanka is currently in the prevention of re-introduction phase of malaria. The engagement of the private sector health care institutions in malaria surveillance is important. The purpose of the study was to determine the number of diagnostic tests carried out, the number of positive cases identified and the referral system for diagnosis in the private sector and to estimate the costs involved. METHODS: This prospective study of private sector laboratories within the Colombo District of Sri Lanka was carried out over a 6-month period in 2015. The management of registered private sector laboratories was contacted individually and the purpose of the study was explained. A reporting format was developed and introduced for monthly reporting. RESULTS: Forty-one laboratories were eligible to be included in the study and 28 participated by reporting data on a monthly basis. Excluding blood bank samples and routine testing for foreign employment, malaria diagnostic tests were carried out on 973 individuals during the 6-month period and nine malaria cases were identified. In 2015, a total of 36 malaria cases were reported from Sri Lanka. Of these, 24 (67 %) were diagnosed in the Colombo District and 50 % of them were diagnosed in private hospitals. CONCLUSIONS: An equal number of cases were diagnosed from the private sector and government sector in the Colombo District in 2015. The private sector being a major contributor in the detection of imported malaria cases in the country should be actively engaged in the national malaria surveillance system.Item Climate change and malaria(United Nations Publications, 2010) Wickremasinghe, R.; Wickremasinghe, A.R.; Fernando, S.D.Item Importance of active case detection in a malaria elimination programme(BioMed Central, 2014) Wickremasinghe, R.; Fernando, S.D.; Thillekaratne, J.; Wijeyaratne, P.M.; Wickremasinghe, A.R.Introduction of human immunization reduced Japanese Encephalitis (JE) cases dramatically in Sri Lanka. However, the increased reporting ofadverse events following immunization (AEFI) affected vaccine acceptance by the community. Against this background, we describe the incidence of overall AEFI and incidence and profile of AEFI, thought to be causally related to the mouse-brain derived JE vaccine. A follow-up of 9798 vaccine recipients was performed for a period of two weeks post-vaccination. Parents self-recorded observed signs and symptoms. The self-records were collected by trained supervisors. All monitored children who manifested symptom/s were investigated in details by medical officers experienced in AEFI investigations within two weeks after ending the follow-up period. Using the results of the investigation, the causality assessment was performed. The estimated cumulative incidence rate of overall AEFI was 8.6 children per 100 immunizations. The same for observed AEFI consistent with causal association to the inactivated JE vaccine was 4.3 children (95% CI-3.9-4.7%) per 100 immunizations. The most frequent AEFI was fever (81%). The frequency of high fever (>102 °F) was 26%. Other major AEFI were body ache (22%) vomiting (21%), urticaria (19%), pruritus (5%), and headache (5%). Though 83% of children with AEFI thought to be causally related to the vaccine sought medical care, only 6.6% required hospitalizations. The incidence rate of AEFI in the cohort event monitoring was several-fold higher than that reported through the national AEFI surveillance system. The incidence rate of allergic manifestations among Sri-Lankan children approached what was reported for non-endemic settings and was higher than in other JE endemic populations elsewhere. Contrary to the belief of medical practitioners and the general public, incidence of seizures was low and vaccine related other neurological manifestations were absent.Item The social and economic burden of malaria in Sri Lanka(2005) Wickremasinghe, A.R.; Wickremasinghe, R.; Fernando, S.D.; Galappaththi, G.; Mahawithanage, S.T.C.Item Impact of childhood malaria in Sri Lanka(2005) Fernando, S.D.; Wickremasinghe, R.; Wickremasinghe, A.R.; Mahawithanage, S.T.C.Item A cost analysis of the use of the rapid, whole-blood, immunochromatographic P.f/P.v assay for the diagnosis of Plasmodium vivax malaria in a rural area of Sri Lanka(Academic Press, 2004) Fernando, S.D.; Karunaweera, N.D.; Fernando, W.P.; Attanayake, N.; Wickremasinghe, A.R.Between May 2001 and March 2002, a prospective study was conducted in a malaria-endemic area of Sri Lanka, to determine the cost implications of using the immunochromatographic P.f/P.v test to detect Plasmodium vivax infection. All consecutive subjects aged >5 years who presented with a history of fever were recruited. Each was checked for P. vivax infection by the standard microscopical examination of bloodsmears and by theimmunochromatographic test (ICT). The costs of diagnosis using each method and the sensitivity, specificity and predictive values of the ICT (with blood smear examination used as the 'gold standard') were estimated, the costs/case detected being simulated for different slide positivity 'rates' and ICT sensitivities. In the detection of P. vivax, the ICT had a sensitivity of 70% and a specificity of 99%. The costs of the ICT per subject investigated and per case detected were, respectively, approximately 14 and 20 times more than those of bloodsmear examination. The costs of the ICT per case detected would fall as the sensitivity of the test increased. The ICT gave relatively few false-positive results. The current, relatively high cost of the ICT is the most important barrier to its routine operational use in the diagnosis of malaria. The test is already useful, however, in specific situationsItem The impact of repeated malaria attacks on the school performance of children(American Society of Tropical Medicine and Hygiene, 2003) Fernando, S.D.; Gunawardena, D.M.; Bandara, M.R.; de Silva, D.; Carter, R.; Mendis, K.N.; Wickremasinghe, A.R.The impact of repeated malarial infections on the school performance of children was investigated in 571 school children 6-14 years of age in a malaria-endemic area in southern Sri Lanka where both Plasmodium falciparum and P. vivax infections are prevalent. Malaria infections confirmed by microscopy were monitored over a six-year period. School performance was assessed by two specially designed, school grade-specific, test papers for Sinhala language and mathematics. The scores for Sinhala language and mathematics for each school term test for the year 1997 were obtained. Malarial infections were a major predictor of children's performance in language and mathematics after controlling for parent's education, monthly family income, and house type. The education of the father predicted language scores but not mathematics scores. A child who experienced more than five attacks of malaria scored approximately 15 percent less than a child who experienced less than three attacks of malaria. The data suggest that repeated attacks of malaria have an adverse impact on the school performance of children.