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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty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 Effect of daily stressors and collective efficacy on post-traumatic stress symptoms among internally displaced persons in post-war northern Sri Lanka(Cambridge University Press, 2023) Somasundaram, D.; Jayasuriya, R.; Perera, R.; Thamotharampillai, U.; Wickremasinghe, R.; Tay, A.K.BACKGROUND: Daily stressors have been shown to mediate the relationship of war trauma and trauma-related distress among refugees and internally displaced persons exposed to war and conflict. AIMS: To examine the extent to which the relationship between war-related trauma and mental distress was mediated by daily stressors and collective efficacy among internally displaced communities a decade after exposure to war. METHOD: In a cross-sectional study, we recruited a random sample of residents in villages severely affected by conflict in five districts in the Northern Province of Sri Lanka. Measures of war trauma, daily stressors, collective efficacy and post-traumatic stress symptoms (PTSS) were examined. Statistical analyses of the mediating and moderating effects of daily stressors were conducted using regression based methods. RESULTS: Daily stressors mediated the association of war trauma and PTSS, as both paths of the indirect effect, war trauma to daily stressors and daily stressors to PTSS, were significant. The predictive effect of war trauma on PTSS was positive and significant at moderate and high levels of daily stressors but not at low levels. Higher levels of neighbourhood informal social control, a component of collective efficacy, function as a protective factor to reduce effects of war trauma and daily stressors on mental distress in this population. CONCLUSIONS: Daily stressors are an important mediator in the well-established relationship between war exposure and traumatic stress among internally displaced persons, even a decade after the conflict. Mental health and psychosocial support programmes that aim to address mental distress among war-affected communities could reduce daily stressors and enhance collective efficacy in this context.Item Laboratory scale evaluation of the feasibility of locally found bladderworts as biological agents to control dengue vector, Aedes aegypti in Sri Lanka(BioMed Central, 2023) Gunathilaka, N.; Perera, R.; Amerasinghe, D.; Udayanga, L.BACKGROUND: The carnivorous genus Utricularia also includes aquatic species that have the potential to trap a wide range of prey, leading its death due to anoxia. However, the effectiveness of such an approach with carnivorous plants for vector control has not been evaluated in Sri Lanka. METHODS: Early instar (i & ii) and late instar (iii & iv) larvae of Aedes aegypti were exposed to locally found bladderwort (U. aurea Lour and Utricularia sp.). The experimental design was set with 10 larvae (both early and late instars separately) in 250 mL of water with bladderworts containing approximately 100 bladders in plant segments of both species, separately. Each treatment and control were repeated 50 times. The survival status of larvae was recorded daily until death or adult emergence. The larvae found whole or partially inside the bladders were attributed to direct predation. The Cox-regression model and Mantel-Cox log rank test were carried out to assess the survival probabilities of larvae in the presence of two bladderworts separately. RESULTS: The highest predation was observed when using early instar larvae in both U. aurea (97.8%) and Utricularia sp. (83.8%). The mortality caused due to predation by U. aurea was observed to be significantly higher according to the Mantel-Cox log-rank test (HR = 60.71, CI; 5.69-999.25, P = 0.004). The mortality rates of late instar stages of Ae. aegypti were observed to be lower in both U. aurea (82.6%) and Utricularia sp. (74.8%). Overall, the highest predation efficacy was detected from U. aurea (HR = 45.02; CI: 5.96-850.51, P = 0.017) even in late instar stages. The results suggested the cumulative predation in both plants on Ae. aegypti larvae was > 72%. CONCLUSIONS: Utricularia aurea is a competent predator of Ae. aegypti larvae. Further, it is recommended to evaluate the feasibility of this plant to be used in the field as a control intervention in integrated vector management programmes.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 Incidence and risk factors for Non-Alcoholic Fatty Liver Disease in an urban, adult Sri Lankan population – a community cohort follow-up study(Sage Publishing, 2015) Niriella, M.; Kasturiratne, A.; de Silva, S.; Perera, R.; Subasinghe, C.; Kodisinghe, K.; Priyantha, C.; Rishikeshavan, V.; Dassanayake, A.; de Silva, A.; Pathmeswaran, A.; Kato, N.; de Silva, H.J.INTRODUCTION: We previously reported a community prevalence of 33% for NAFLD in an urban, adult Sri Lankan population. We also found a significant association between patatin-like phospholipase domain containing 3 (PNPLA3) gene rs738409 polymorphism, and susceptibility to NAFLD in the same population, after testing 10 selected single nucleotide polymorphisms (SNPs) in a case control study. AIMS & METHODS: The aim of this study was to assess the incidence and risk factors for NAFLD in this population after seven years of follow-up. The study population consisted of 42-71-year-old adults, originally selected by age stratified random sampling from electoral lists from Ragama, Sri Lanka. The target population was screened initially in 2007 and subsequently invited back for re-evaluation in 2014. On both occasions they were assessed using a structured interview, clinical and anthropometric measurements, liver ultrasound, and biochemical and serological tests. NAFLD was diagnosed on established ultrasound criteria for fatty liver (two out of three criteria: increased echogenecity of the liver compared to kidney and spleen, obliteration of the vascular architecture of the liver and deep attenuation of the ultrasonic signal), safe alcohol consumption (Asian standards: 514 units/week for men, 57 units/week for females) and absence of hepatitis B and C markers. Non-NAFLD controls were defined as subjects who did not have any of the ultrasound criteria for NAFLD. We also performed an updated case-control study to investigate associations of selected genetic variants with incident NAFLD [SNPs: PNPLA3 (rs738409), LYPLAL1 (rs12137855), GCKR (rs780094), PPP1R3B (rs4240624) and NCAN (rs2228603), APOC3 (rs2854117 and rs2854116), ADIPOR2 (rs767870) and STAT3 (rs6503695 and rs9891119)]. RESULTS: Of the 2985 original study participants, 2155 (72.2%) (1244 women and 911 men; mean age 59.2 years [SD, 7.7]) participated in the follow-up assessment. 1322 [mean age 58.9 years (SD, 7.6), 483 (53.0%) men and 839 (67.4%) women] had NAFLD. Out of 795 [466 (58.6%) women] participants who did not have NAFLD in the original study, 365 [226 (61.9%) women, mean age 58.6 years (SD, 7.9)] had developed NAFLD after 7 years, giving an annual incidence rate 6.6%. On multivariate analysis, increased waist circumference [OR 1.96(1.30 – 2.97), p=0.001], BMI4 23 kg/m2 [OR 2.93(1.99 – 4.30), p50.001] and raised plasma triglycerides (TG) [OR 1.49(1.03 – 2.13), p=0.03] were independently predictive of incident NAFLD in this cohort, while raised BP and reduced HDL, were not. In the updated association study involving 1310 cases and 427 controls, we found borderline association with NAFLD at two of the 10 candidate loci: rs4240624 at PPP1R3B and rs738409 at PNPLA3 (one-tailed P=0.044 and 0.033, respectively). CONCLUSION: In this community cohort follow-up study in an urban, adult population in Sri Lanka, the annual incidence of NAFLD was 6.6%. Incident NAFLD was associated with features of the metabolic syndrome, and showed tendency of association at PNPLA3 and PPP1R3B gene polymorphisms. Disclosure of Interest: None declared