Laboratory scale evaluation of the feasibility of locally found bladderworts as biological agents to control dengue vector, Aedes aegypti in Sri Lanka.

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.

Undergraduate perceptions on transitioning into E-learning for continuation of higher education during the COVID pandemic in a developing country: a cross-sectional study from Sri Lanka.

BACKGROUND: The higher education was significantly influenced by the COVID pandemic within many developing countries, including Sri Lanka, necessitating to adopt more E-Learning opportunities. Therefore, this study was conducted to characterize the perceptions of Sri Lankan undergraduates to accept E-Learning in higher education, during the COVID crisis. METHOD: A total of 657 randomly selected undergraduates of three state universities in Sri Lanka, were recruited as the study population. Information on Socio-demographic factors, Knowledge, Attitudes and Practices on E-Learning methods were acquired using an interviewer administered questionnaire. A Probit regression model was fitted to identify the driving factors for the willingness of undergraduates to engage in E-Learning. RESULTS: Around, 80.2% of the respondents were females. Majority were residing in semi-urban areas (44.7%), followed by rural areas (39.9%). More than two third of the respondents were familiar with E-Learning and different Learning Management Systems (LMS) that facilitate E-Learning (68.9%). Majority of the respondents (73.7%) were using different E-Learning platforms, mostly 2 to 3 days per week (25.7%). Only around one third (36.4%) had received any formal training in using LMS or other E-Learning platforms. Smart phones (77.8%) were found to be the most preferred device used for E-Learning activities, followed by computers and laptops (21.3%). Meanwhile, LMS/MOODLE (45.4%), WhatsApp/Viber (33.0%) and Zoom (32.7%), were the most commonly used E-Learning platforms. The average acceptance of E-Learning methods was found to be 70.7% among Sri Lankan undergraduates during the COVID epidemic. Based on the Probit regression, nature of the residing locality (P=0.009), family income (P=0.048), academic field (P<0.001) and year (P=0.028), knowledge on Information and Communications Technology [ICT] (P=0.012), and previous training experiences on E-Learning (P<0.001) were found as significant drivers that influence the acceptance of E-Learning practices of the Sri Lankan undergraduates. CONCLUSION: Adopting E-learning into higher education sector could be recognized as a viable solution to facilitate the higher education during a crisis like COVID. However, relevant authorities in Sri Lanka should take immediate actions to empower the physical resources for E-Learning, improve the basic telecommunication infrastructure and conduct appropriate training programmes to promote E-Learning among Sri Lankan undergraduates.

Demographic, socio-economic and other associated risk factors for self-medication behaviour among university students of Sri Lanka: a cross sectional study.

BACKGROUND: Self-prescribing practices are considered as a significant issue in the health sector due to mal-practices. This has become a more worsen issue in developing countries with easy access to medication. Current study was undertaken to estimate the prevalence of self-medication and to evaluate the driving factors behind this behavior, among university students of Sri Lanka. METHOD: A total of 700 randomly selected undergraduates of three state universities in Sri Lanka, were recruited as the study population for the cross-sectional study. Information on socio-demographic, Knowledge, Attitudes and Practices relevant to Self-Medication (SM) were gathered using an interviewer administered questionnaire. Binary logistic regression was used to calculate the Odds Ratios (OR) and the 95% confidence intervals of the OR for socio-demographic risk factors on SM. RESULTS: Around 78% of the studied population denoted a SM behaviour. Only, 37.7% of respondents were familiar with the classification of "Over the Counter" (OTC) drugs, while majority were well aware of the risks of SM (> 50%). Fever (61.3%) and cough (56.7%) were the major health issues for SM, while antipyretics and drugs for cough and runny nose (73.6%) were the mostly used medication. Previous experience (76%) and trivial nature of health issues (73%) were recognized as the major reasons for SM. Majority of respondents declared that community pharmacies (86.9%) and left over medication from previous prescriptions (51%) were the sources for SM. Based on the binary logistic regression, age, residence locality, field of study and academic year were recognized as significant risk factors (P < 0.05) for SM within the studied undergraduate population. CONCLUSION: Based on the high prevalence rate of SM, the health authorities of Sri Lanka should pay more attention towards the wellbeing and responsible medication usage of undergraduates. Designing of effective tools and regulations to monitor the selling of medication and improving the health education are recommended to ensure responsible SM within the country.

Prevalence of Ectoparasitic Infections and Other Dermatological Infections and Their Associated Factors among School Children in Gampaha District, Sri Lanka.

Skin disorders are one of the commonest conditions among school children in developing countries. There are only a few published studies available from Sri Lanka on the prevalence of skin disorders. A community-based cross-sectional study was carried out among five government-run schools randomly selected from the district of Gampaha, Sri Lanka, during 2016-2017. A total of 41 students between 5 and 16 years of age were randomly selected from each school. Sociodemographic profile and hygienic behaviors of selected students were assessed using a pretested interviewer-administered questionnaire. Students were examined by a medical officer for the presence of different skin disorders. The chi-squared test of association and binary logistic regression were used for the identification of the significance of socioeconomic factors and hygienic practices among the study participants. A total of 205 school children participated in the study. The commonest skin disorder was pediculosis (42.0%; n=86), followed by dandruff (8.3%; n=17), fungal infections (6.8%; n=14), and scabies (1.5%; n=3). Almost one-fourth of the study participants (22.9%; n=30/131) had more than one disorder, majored by Pediculus captis infestation with dandruff. Over one-third (36.1%; n=74) were free of any skin disorders. The prevalence of skin disorders was significantly high among females (87.3%; n=110), compared to males (26.6%; n=21). Presence of long hair, higher family size, and limited number of rooms in the house were risk factors associated with the prevalence of skin disorders. The commonest skin disorder was pediculosis, while scabies and fungal infections were scarce among school children in the district of Gampaha, Sri Lanka. Implementation of health education and monitoring programs at the school level for maintaining the dermal health status of school children is recommended.

Socio-economic, Knowledge Attitude Practices (KAP), household related and demographic based appearance of non-dengue infected individuals in high dengue risk areas of Kandy District, Sri Lanka.

BACKGROUND: Socio-economic, demographic factors and Knowledge Attitude Practices (KAPs) have been recognized as critical factors that influence the incidence and transmission of dengue epidemics. However, studies that characterize above features of a risk free or low risk population are rare. Therefore, the present study was conducted to characterize the household related, demographic, socio-economic factors and KAPs status of five selected dengue free communities. METHOD: An analytical cross-sectional survey was conducted on selected demographic, socio-economic, household related and KAPs in five selected dengue free communities living in dengue risk areas within Kandy District, Central Province, Sri Lanka. Household heads of 1000 randomly selected houses were interviewed in this study. Chi-square test for independence, cluster analysis and Principal Coordinates (PCO) analysis were used for data analysis. RESULTS: Knowledge and awareness regarding dengue, (prevention of the vector breeding, bites of mosquitoes, disease symptoms and waste management) and attitudes of the community (towards home gardening, composting, waste management and maintenance of a clean and dengue free environment) are associated with the dengue free status of the study populations. CONCLUSIONS: The vector controlling authorities should focus on socio-economic, demographic and KAPs in stimulating the community to cooperate in the integrated vector management strategies to improve vector control and reduce transmission of dengue within Kandy District.

Assessment of Knowledge and Attitude Towards the Palliative Care Among Nurses in Sri Lanka: A Hospital-Based Study.

Objective: Palliative care is an intervention that improves the quality of life of patients. Nurses have a primary role in providing palliative care. Their knowledge and attitudes toward palliative care is important in care delivery. There is minimal information in Sri Lanka to document the knowledge and attitude of palliative care among nurses. Therefore, the present study was conducted to assess the knowledge and attitude of palliative care among nurses in Sri Lanka. Method: A cross-sectional, descriptive study was conducted on 200 selected nurses at Colombo North Teaching Hospital, Sri Lanka fulfilling the inclusion criteria. Socio-demographic information of the study participants was obtained through a self-administered questionnaire. The awareness and attitude levels toward the PC were assessed using the Palliative Care Knowledge Test (PCKT) and Frommelt Attitude Toward Care of the Dying, respectively. Results: More than half of the participants (55%) had an inadequate knowledge level regarding the palliative care (<50% for the PCKT score). Regarding the attitude on the palliative care, the majority stated nursing care to a dying person is a worthwhile experience (92%; n = 184). Many of them disagreed with avoiding the care of dying patients (strongly disagree: 37%; n = 74, disagree: 52.5%; n = 105). Overall, 85.5% of study participants had a positive attitude towards the palliative care. According to binary logistic regression, gender (P = .04; OR = 3.57; CI = 1.03-12.41) and working setup (P < .001) were significantly associated with having a positive attitude. The knowledge level was higher among nurses working in surgical wards (OR = 7.84). Those with >10 years of experience were statistically significant to have a positive attitude (P = .02; OR = 1.35; CI = 1.13-5.50). Conclusion: The nurses had inadequate knowledge of the PC even though they had a positive attitude toward it. Therefore, it is essential to uplift the awareness level among health workers. This warrants the need for palliative care education in the nursing curriculum and continuous professional development.

Knowledge, perceptions and practices on healthcare waste management and associated occupational health hazards among healthcare professionals in the Colombo District, Sri Lanka: a cross-sectional study.

Background: Proper Healthcare Waste (HW) management is directly influenced by the knowledge and attitudes of Healthcare Professionals (HCP). However, studies that characterize the knowledge and practices of HCP on HW management are limited in Sri Lanka. This study was conducted to characterize the knowledge, perceptions and practices of HCP on the management of HW and to determine the risk factors influencing HW related occupational health hazards in the Colombo District of Sri Lanka. Methods: A total of 407 HCP were recruited as the study population from selected hospitals in the Colombo District. Information on socio-demographic factors, knowledge, attitudes and practices on HW management were gathered using an interviewer-administrated questionnaire. The Binary Logistic Regression (BLR) was used to determine the socio-economic risk factors associated with the occurrence of HW related health issues among the respondents. Results: The majority of respondents were characterized with a high knowledge level (76.9%) and positive attitudes (53.8%) on HW management. Incineration (82.6%) was recognized as the most widely used HW treatment method. Personal Protective Equipment (PPE) was used at a satisfactory level (85.5%), while liquid waste treatment was limited (57.5%). The occupational designation, level of training received in HW management, professional experience, vaccination status for tetanus, degree of knowledge and attitudes on HW management were recognized as significant risk factors (p < 0.05) associated with the occurrence of HW related occupational hazards. Conclusion: Even though, the treatment of HW was satisfactory, strengthening the existing mechanisms for monitoring of HW management, provisioning more resources and organizing training and awareness programmes on HW management for HCP are recommended.

Knowledge, perceptions, and consumption behaviour of cosmetics among undergraduates of Sri Lanka: a descriptive cross-sectional study.

Background: Despite the increasing usage of personal care products among young adolescents in Sri Lanka, limited studies have been conducted to understand the behaviour of cosmetic users and associated health complications. Therefore, the current study was conducted to evaluate the cosmetic consumption related behaviour of the undergraduate community in Sri Lanka and to identify the driving factors behind the incidences of cosmetic related adverse health effects. Method: An analytical cross-sectional study was conducted by recruiting 421 undergraduates from five state universities in Sri Lanka through stratified random sampling, as the study population. Information on socio-demographic factors and cosmetic consumption behaviour of the participants were acquired through a self-administrated structured questionnaire, along with Knowledge, Attitudes and Practices (KAP) relevant for cosmetic usage. The Binary Logistic Regression model was used to determine the significant socio-demographic driving factors on cosmetic usage among the undergraduate community in Sri Lanka at a confidence level of 95%. Results: Around 96.4% of the study population used one or more cosmetic products (77%) out of which, 75.3% experienced cosmetic related adverse health effects. Skin dryness (24%), acne (21%), allergies (20.5%) and rashes (19.8%), were identified as the most dominant adverse health effects, related to cosmetic usage. Perfumes (65.6%), face cream (63.2%) and body lotion/hand cream (60.6%), were the mostly used cosmetic products. Even though half of the study population exhibited higher levels of good practices during purchase (54.9%) and application (52%) of cosmetics, around 47.5% were characterized with a low level of knowledge on cosmetics. Gender, academic year, knowledge on cosmetics, monthly expenditure on cosmetics, source of recommendation for cosmetics, practices related to purchase and consumption of cosmetics and preference to receive medical care in case of cosmetic related emergency were recognized as significant risk factors (p < 0.05) associated with the incidence of cosmetic related adverse health effects among undergraduate students. Conclusion: Given the high prevalence of cosmetic related adverse health effects, the health authorities of Sri Lanka should pay more attention towards the wellbeing and responsible cosmetic usage among undergraduates. Designing of effective tools and regulations to monitor the cosmetic market and improving the knowledge on cosmetics are recommended to ensure safe cosmetic usage within the country in general and of adolescent users in particular.

Comparative analysis of the larvicidal activity of temephos (EC50) and novaluaron (EC10) to control Anopheles stephensi in Sri Lanka.

BACKGROUND: Anopheles stephensi was first recorded in the coastal area of Mannar District, Sri Lanka, in December 2016. Since then, this vector has been isolated from other districts in the Northern and Eastern Provinces of Sri Lanka. Chemical control is the main arm of vector control that can be used to reduce the vector densities within a short period. Thus, the present study aimed at evaluating the efficacy of using selected insecticides for the control of An. stephensi larvae. METHOD: The third and fourth instar larval stages of An. stephensi (F2 generation) of field mosquitoes that were caught using cattle baited net trap collections from Columbuthurai, Kurunagar, and Navanthurai areas in Jaffna District, Sri Lanka, were obtained from the laboratory colony established at Jaffna. Batches of 100 larvae were taken for experiments and introduced separately to a concentration series of temephos and novaluron (0.04-400 ppm). A control test was also performed at each setup without introducing insecticides. The mortality rates of An. stephensi larvae exposed to different concentrations of larvicides were recorded at 1, 24 and 48-h intervals. The experiment was replicated five times at individual concentrations for each selected chemical. Data were analyzed using the General Linear Model (GLM) and Probit analysis. RESULTS: The highest mortality rate (100%) at a 1-h exposure period was observed from temephos at >100 ppm. The mortality rates varied significantly for different concentrations and larvicides (p < 0.05). At 24-h of the exposure period, the 100% mortality of An. stephensi larvae were observed from both temephos and novaluron even at 0.04 ppm. CONCLUSION: Both temephos and novaluron reported 100% mortality rates in An. stephensi larvae at 1-h and 24-h exposure periods. Based on the findings, temephos and novaluron can be recommended as effective larvicides for chemical-based control of An. stephensi in Jaffna, Sri Lanka. Further, it is recommended to conduct a field-based study, where habitat types and water quality are highly heterogeneous and may affect the residual activity.

Diversity of midgut bacteria in larvae and females of Aedes aegypti and Aedes albopictus from Gampaha District, Sri Lanka.

BACKGROUND: The midgut microbiota of mosquitoes maintain basal immune activity and immune priming. In recent years, scientists have focused on the use of microbial communities for vector control interventions. In the present study, the midgut bacteria of larvae and adults of Aedes aegypti and Ae. albopictus were assessed using both field-collected and laboratory-reared mosquitoes from Sri Lanka. METHODS: Adults and larvae of Ae. aegypti and Ae. albopictus were collected from three selected areas in Gampaha Medical Officer of Health area, Gampaha District, Western Province, Sri Lanka. Bacterial colonies isolated from mosquito midgut dissections were identified by PCR amplification and sequencing of partial 16S rRNA gene fragments. RESULTS: Adults and larvae of Ae. aegypti and Ae. albopictus harbored 25 bacterial species. Bacillus endophyticus and Pantoea dispersa were found more frequently in field-collected Ae. aegypti and Ae. albopictus adults, respectively. The midgut bacteria of Ae. aegypti and Ae. albopictus adults (X2 = 556.167, df = 72, P < 0.001) and larvae (X2 = 633.11, df = 66, P < 0.001) were significantly different. There was a significant difference among the bacterial communities between field-collected adults (X2 = 48.974, df = 10, P < 0.001) and larvae (X2 = 84.981, df = 10, P < 0.001). Lysinibacillus sphaericus was a common species in adults and larvae of laboratory-reared Ae. aegypti. Only P. dispersa occurred in the field-collected adults of Ae. aegypti and Ae. albopictus. Species belonging to genera Terribacillus, Lysinibacillus, Agromyces and Kocuria were recorded from Aedes mosquitoes, in accordance with previously reported results. CONCLUSIONS: This study generated a comprehensive database on the culturable bacterial community found in the midgut of field-collected (Ae. aegypti and Ae. albopictus) and laboratory-reared (Ae. aegypti) mosquito larvae and adults from Sri Lanka. Data confirm that the midgut bacterial diversity in the studied mosquitoes varies according to species, developmental stage and strain (field vs laboratory).

Voltage-Gated Sodium Channel (Vgsc) Mutation-Based Pyrethroid Resistance in Aedes aegypti Populations of Three Endemic Dengue Risk Areas of Sri Lanka.

BACKGROUND: Pyrethroid insecticides are widely used in many countries for chemical-based control of Ae. aegypti. Regardless of their efficacy, the constant use of insecticides has induced insecticide resistance mechanisms, such as knockdown resistance (kdr) in mosquitoes. Sri Lankan Vector Controlling Entities (VCE) have been using a variety of pyrethroid insecticides as the primary approach for dengue control. However, development of any resistance among the Aedes mosquitoes has been limitedly studied in the country. Therefore, the current study was conducted to evaluate the prevalence of F1534C, V1016G, and S989P mutations among Ae. aegypti mosquito populations in three dengue endemic high-risk regions of Sri Lanka. Methodology. Immature (both pupae and larvae) stages of Ae. aegypti mosquitoes were collected from Colombo, Gampaha, and Kandy districts of Sri Lanka from February 2018 to December 2019. Polymerase Chain Reaction- (PCR-) based assay for molecular genotyping of mutations was performed to identify the prevalence of kdr mutations in collected Ae. aegypti populations, separately. The frequencies of the resistant and susceptible kdr alleles were determined by using the Hardy-Weinberg equilibrium. RESULTS: The Ae. aegypti populations from Colombo, Gampaha, and Kandy districts showed 46%, 42%, and 22% of F1534C mutation allele frequencies, along with 15%, 12%, and 6% of V1016G mutation allele frequencies, respectively. The mutation allele frequencies of S989 in Colombo, Gampaha, and Kandy districts were 9.5%, 8.5%, and 4.5%, respectively. The wild-type (PP) genotype remained predominant within all the three districts, whereas the homogenous (QQ) mutation genotype occurred only in minority. The abundance of Q allele frequency in Ae. aegypti mosquitoes was relatively higher for all the three mutations in Colombo. CONCLUSIONS: The findings clearly indicate that long-term insecticide applications and multiple use of pyrethroids have led to the acquisition of kdr mutations, leading to the development of insecticide resistance among local Ae. aegypti populations, especially in the Colombo and Gampaha districts. Therefore, evaluation of the prevalence levels of these kdr mutations highlights the necessity for shifting towards novel vector control strategies.

Breeding Habitat Distribution of Medically Important Mosquitoes in Kurunegala, Gampaha, Kegalle, and Kandy Districts of Sri Lanka and Potential Risk for Disease Transmission: A Cross-Sectional Study.

Some arbovirus infections, especially dengue, have increased rapidly over the last few decades in Sri Lanka. Prevalence and distribution of different mosquito species have been limitedly documented, which remains grossly inadequate in providing evidence for potential health risks. In this study, the diversity and species composition of mosquitoes in four selected districts in Sri Lanka (Kurunegala, Gampaha, Kegalle, and Kandy) were investigated. Entomological surveys were conducted from a total of 160 temporary and permanent mosquito breeding habitats identified in the study area from June 2017 to October 2018. Mosquito immature stages were sampled using standard dipping, siphoning, or pipetting methods and identified up to the species level. Percentage relative abundance and habitat characteristics such as species richness, dominance, and Shannon-Weiner diversity were calculated for each surveyed habitat type. Associations between co-occurring species were estimated by Hulbert's coefficient of interspecific association (C8). A total of 4663 mosquito larvae belonging to seven genera and fifteen species of mosquitoes were collected. The relative distribution of mosquito species differed significantly among the four studied districts (X 2 = 143.248; df = 33; P < 0.001). According to Kruskal-Wallis statistics (P < 0.05 at 95% of significance), all diversity indices for immature stages of medically important mosquitoes varied significantly across different breeding sites. Paddy fields had the significantly highest species richness of 4.0 ± 2.82. The coefficients of interspecific association among all the recorded medically important vector mosquitoes were found negative during the present study. The findings of the current study would be useful to identify the entomological potential for disease transmission and facilitate the implementation of appropriate vector control interventions. This would ultimately provide an avenue to improve the personal skills of health staff rather than limiting their knowledge to specified disease vectors, under which the control program is concerned.

Field-based evaluation of novaluron EC10 insect growth regulator, a chitin synthesis inhibitor against dengue vector breeding in leaf axils of pineapple plantations in Gampaha District, Sri Lanka.

BACKGROUND: Insect growth regulators (IGRs) are considered a novel group of insecticides to control mosquitoes. Novaluron is an IGR with benzoylphenyl urea insecticide, which inhibits chitin synthesis in insects and can reduce insect population density; it is also known to have a high margin of safety for mammals. METHODS: The effective minimum concentration of novaluron formulation EC10 was tested. Six pineapple plantations [control (n = 3) and test (n = 3)] were selected from Meerigama Medical Officer of Health area in Gampaha District, Sri Lanka. Fifteen plots (10 × 10 m) were demarcated in each site with a 200 m distance apart. Leaf axils of 450 pineapple plants (30 plants × 15 plots) were screened for immature stages of Aedes mosquitoes weekly for 12 weeks. The required concentration (20 ppm) of novaluron was sprayed onto the selected pineapple plants (n = 1350) individually in 3 selected test sites for 5-10 s. The reduction in the vector population was interpreted as the percentage of reduction in immature stages of Aedes mosquitoes. RESULTS: The 100% mortality of the Ae. aegypti larvae within 24 h was observed at 20 ppm (0.05 ml of novaluron 100 g/l in 250 ml of water) as the minimum dose. Variation in the number of Aedes larvae present in the control and intervention sites was found to be significantly different throughout the entire observational period (χ2 = 128.29, df = 11, P < 0.001). The total elimination of Aedes larvae continued for up to 2 weeks and a 50% reduction was observed until the 8th week. CONCLUSIONS: The present study emphasizes that novaluron (10% EC) can be used as an effective larvicide at the treatment dose of 20 ppm. The residual effect of the IGR lasted for 12 weeks with a functional efficacy of 8 weeks. The 100% reduction of larval breeding was observed up to the 2nd week after application and the percentage reduction of immature stages remained > 50% until the 8th week. The lowest reduction (34.2%) was observed at 12 weeks after the initial treatment. Therefore, re-treatment may be recommended based on the reduction in the efficacy of the IGR.

Climate change induced vulnerability and adaption for dengue incidence in Colombo and Kandy districts: the detailed investigation in Sri Lanka.

BACKGROUND: Assessing the vulnerability of an infectious disease such as dengue among endemic population is an important requirement to design proactive programmes in order to improve resilience capacity of vulnerable communities. The current study aimed to evaluate the climate change induced socio-economic vulnerability of local communities to dengue in Colombo and Kandy districts of Sri Lanka. METHODS: A total of 42 variables (entomological, epidemiological, meteorological parameters, land-use practices and socio-demographic data) of all the 38 Medical Officer of Health (MOH) areas in the districts of Colombo and Kandy were considered as candidate variables for a composite index based vulnerability assessment. The Principal Component Analysis (PCA) was used in selecting and setting the weight for each indicator. Exposure, Sensitivity, Adaptive Capacity and Vulnerability of all MOH areas for dengue were calculated using the composite index approach recommended by the Intergovernmental Panel on Climate Change. RESULTS: Out of 42 candidate variables, only 23 parameters (Exposure Index: six variables; Sensitivity Index: 11 variables; Adaptive Capacity Index: six variables) were selected as indicators to assess climate change vulnerability to dengue. Colombo Municipal Council (CMC) MOH area denoted the highest values for exposure (0.89: exceptionally high exposure), sensitivity (0.86: exceptionally high sensitivity) in Colombo, while Kandy Municipal Council (KMC) area reported the highest exposure (0.79: high exposure) and sensitivity (0.77: high sensitivity) in Kandy. Piliyandala MOH area denoted the highest level of adaptive capacity (0.66) in Colombo followed by Menikhinna (0.68) in Kandy. The highest vulnerability (0.45: moderate vulnerability) to dengue was indicated from CMC and the lowest indicated from Galaha MOH (0.15; very low vulnerability) in Kandy. Interestingly the KMC MOH area had a notable vulnerability of 0.41 (moderate vulnerability), which was the highest within Kandy. CONCLUSIONS: In general, vulnerability for dengue was relatively higher within the MOH areas of Colombo, than in Kandy, suggesting a higher degree of potential susceptibility to dengue within and among local communities of Colombo. Vector Controlling Entities are recommended to consider the spatial variations in vulnerability of local communities to dengue for decision making, especially in allocation of limited financial, human and mechanical resources for dengue epidemic management.

Larval Indices of Vector Mosquitoes as Predictors of Dengue Epidemics: An Approach to Manage Dengue Outbreaks Based on Entomological Parameters in the Districts of Colombo and Kandy, Sri Lanka.

BACKGROUND: Early detection of dengue epidemics is a vital aspect in control programmes. Predictions based on larval indices of disease vectors are widely used in dengue control, with defined threshold values. However, there is no set threshold in Sri Lanka at the national or regional levels for Aedes larval indices. Therefore, the current study aimed at developing threshold values for vector indices in two dengue high-risk districts in Sri Lanka. METHODS: Monthly vector indices (House Index [HI], Container Index [CI], Breteau Index for Aedes aegypti [BIagp], and Ae. albopictus [BIalb]), of ten selected dengue high-risk Medical Officer of Health (MOH) areas located in Colombo and Kandy districts, were collected from January 2010 to June 2019, along with monthly reported dengue cases. Receiver Operating Characteristic (ROC) curve analysis in SPSS (version 23) was used to assess the discriminative power of the larval indices in identifying dengue epidemics and to develop thresholds for the dengue epidemic management. RESULTS: Only HI and BIagp denoted significant associations with dengue epidemics at lag periods of one and two months. Based on Ae. aegypti, average threshold values were defined for Colombo as Low Risk (2.4 ≤ BIagp < 3.8), Moderate Risk (3.8 ≤ BIagp < 5), High Risk (BIagp ≥ 5), along with BIagp 2.9 ≤ BIagp < 4.2 (Low Risk), 4.2 ≤ BIagp < 5.3 (Moderate Risk), and BIagp ≥ 5.3 (High Risk) for Kandy. Further, 5.5 ≤ HI < 8.9, 8.9 ≤ HI < 11.9, and HI ≥ 11.9 were defined as Low Risk, Moderate Risk, and High Risk average thresholds for HI in Colombo, while 6.9 ≤ HI < 9.1 (Low Risk), 8.9 ≥ HI < 11.8 (Moderate Risk), and HI ≥ 11.8 (High Risk) were defined for Kandy. CONCLUSIONS: The defined threshold values for Ae. aegypti and HI could be recommended as indicators for early detection of dengue epidemics and to drive vector management activities, with the objective of managing dengue epidemics with optimal usage of financial, technical, and human resources in Sri Lanka.

Development of an Alternative Low-Cost Larval Diet for Mass Rearing of Aedes aegypti Mosquitoes.

BACKGROUND: Aedes aegypti is a major vector of arboviruses that may be controlled on an area-wide basis, using novel approaches such as Sterile Insect Technique (SIT) and Incompatible Insect Technique (IIT). Larval diet is a critical factor to be considered in mass rearing of Aedes mosquitoes for SIT and IIT programs. Therefore, the current study is aimed at evaluating the effects of two novel diets developed from dry fish powder on the growth and development of immature stages and adult fitness-related characteristics of Ae. aegypti in Sri Lanka. METHOD: Three batches of the first instar Ae. aegypti larva, each containing 250 larvae, were exposed to three different larval diets as standard dry fish powder (D1), dry fish powder meal and brewer's yeast (D2), and International Atomic Energy Agency- (IAEA-) recommended diet (D3), separately. Morphometric and developmental parameters of the 4th instar larvae, pupae, and adult mosquitoes reared under different dietary treatments were measured. The entire experimental setup was replicated thrice. A General Linear Model (GLM) in the form of two-way ANOVA was used for the statistical analysis. RESULTS: Significant diet-based variations were observed in the head length, head width, thoracic length, thoracic width, abdominal length, abdominal width, and total length (F 2,87 > 4.811; P < 0.05) of Ae. aegypti larvae. The highest pupation success and the larval size were observed from the larvae fed the D2 diet, while the lowest was reported from D1. All adult morphometric parameters of adult male and female Ae. aegypti mosquitoes also denoted significant dietary variations, reporting the best-sized adults from the D2 diet (F 2,87 > 3.54; P < 0.05). Further, significantly higher fecundity and male longevity were also shown by the adult Ae. aegypti (F 2,6 > 7.897; P < 0.01) mosquitoes reared under diet D2. CONCLUSION: Based on all the growth and developmental parameters, the D2 diet tends to perform similar to the IAEA-recommended diet in mass rearing of Ae. aegypti mosquitoes, while being more inexpensive. Therefore, larval diet D2 could be suggested as the ideal diet for mass rearing of Ae. aegypti for IIT and SIT-based vector control in Sri Lanka.

Prevalence of cutaneous leishmaniasis infection and clinico-epidemiological patterns among military personnel in Mullaitivu and Kilinochchi districts of the Northern Province, early war-torn areas in Sri Lanka.

BACKGROUND: The 30-year-old armed conflict in Sri Lanka resulted in a general breakdown of civil administration in the Northern and Eastern provinces, leading to mobilisation of many armed forces personnel to assist with reconstruction and resettlement. This occupational group has been identified as a priority risk group for leishmaniasis. METHODS: Individuals enlisted at all military establishments in Mullaitivu and Kilinochchi districts, Northern Province of Sri Lanka were included. Five thousand individuals were screened for skin lesions between September 2018 and August 2019. Persons with lesions suspected as cutaneous leishmaniasis (CL) were further investigated. Information on sociodemographic/other potential risk factors was obtained through an interviewer-administered structured questionnaire. The diagnosis was confirmed by microscopic visualization of parasitic stages from different samples obtained (skin scraping, lesion aspirate and tissue impression smears), histopathology and polymerase chain reaction DNA amplification. RESULTS: Among 5000 individuals screened, 74 individuals were suspected of having CL. Of these, 67.6% (n = 50) patients were confirmed for CL by microscopy. Around two third of both males (67.6%; n = 48) and females (66.6%; n = 2) were positive for Leishmania. The soldiers belonging to 26-35-year age group reported the highest susceptibility (83.3%; OR: 4.83, 95% CI: 3.49-6.20%). Of the sociodemographic factors, age, wearing short-sleeved upper body clothing as the uniform and non-use of insect repellents were identified as significant risk factors. Most of the CL patients had a single lesion (86.0%; n = 43) of an ulcerative type (34.0%; n = 17), mostly on their upper limb (67.9%; n = 34). Lesions were mostly 5-10 mm diameter (59.9%; n = 30) in size with poorly defined margins (72.0%; n = 36). Amongst the diagnostic techniques, microscopic examination of slit skin smear and tissue impression smear were able to discriminate the majority of patients (92.1%; n = 46) for CL. CONCLUSIONS: In order to highlight the true burden of leishmaniasis in the military personnel, cases of leishmaniasis from military institutes should be recognized as a different entity per say and be included in the national figures so as to depict the real magnitude of the disease burden amongst this high-risk group.

Assessment of Anxiety, Depression, Stress, and Associated Psychological Morbidities among Patients Receiving Ayurvedic Treatment for Different Health Issues: First Study from Sri Lanka.

BACKGROUND: Good mental condition is a vital part of health. Physical impairments would potentially have psychiatric manifestations during the course of a disease that could cause patients to experience a wide range of psychological conditions. This study was conducted to determine prevalence of anxiety, depression, stress, and psychological morbidities among the patients who received warded treatments at Gampaha Wickramarachchi Ayurveda Teaching Hospital, Sri Lanka. METHODS: A total of 148 patients admitted to the hospital were selected for the study on a random systematic basis under four systemic groups (gastrointestinal, integumentary, musculoskeletal, and nervous system) depending on the chief complaint. The presence of depressive, anxiety, and stress symptoms was assessed by the Depression Anxiety Stress Scale 21 item version (DASS 21). The General Linear Model (GLM) was used for statistical analysis. RESULTS: Over 50% of the participants in all four patient groups belonged to age group of 35 to 65 years, encompassing the fraction of population that actively contribute to the workforce in the society. Stress, anxiety, and depression values of patients belonging to different complications varied significantly, as indicated by GLM (p < 0.05). Patients diagnosed with integumentary system-related issues denoted the highest stress levels (27.7 ± 2.54), while the mean stress values among the other systemic groups were not significantly different among each other. The highest anxiety levels were indicated by patients with nervous system-related issues (18.6 ± 1.51), while the lowest anxiety levels were indicated by patients with integumentary disorders (6.0 ± 2.73). The highest depression level was identified from patients suffering from integumentary system-related disorders (31.7 ± 3.42), followed by nervous system (23.2 ± 1.78), gastrointestinal (19.5 ± 3.77), and musculoskeletal (16.8 ± 1.57) disorders. CONCLUSION: Overall, high distress levels were observed among the majority of the patients. Furthermore, integumentary issues may lead to significant psychological impacts. As most of the patients seek for Ayurveda treatments when their diseased condition becomes chronic, it is vital to focus on a biopsychosocial approach to patient assessment and patient care, in actual practice.

Effect of Larval Nutritional Regimes on Morphometry and Vectorial Capacity of Aedes aegypti for Dengue Transmission.

BACKGROUND: Nutritional level in larval diet of mosquito vectors influence on life history traits and vectorial capacity (VC). Therefore, the present study was carried out to assess the effect of larval diet concentration on vector bionomic and VC of Aedes aegypti in Sri Lanka. METHOD: Three batches of 400 Ae. aegypti larvae (first instar) were reared under different concentrations of larval diet (6%, 8%, and 10%; Volume/Volume), which was prepared by mixing 12.5 g of tuna meal, 9.0 g of bovine liver powder, and 3.5 g of Brewer's yeast, in 100 ml of distilled water. The effect of larval diet concentration on different morphometric and functional parameters of larvae (length and width of head, abdomen, survival rate, and pupation success), pupae (length and width of cephalothorax, survival rate, and adult emersion), adult (length and width of thorax, abdomen, survival rate, longevity, biting frequency and fecundity of adults) were examined. In addition, VC of Ae. aegypti was evaluated. The General Linear Model (GLM) was used for the statistical analysis. RESULTS: Larval head length, head width, thoracic width, abdominal length, abdominal width, total length, and survival rate significantly increased with higher doses of larval diet (P < 0.05). In case of pupae, length, and width of cephalothorax, survival rate and adult emergence rate denoted an increasing trend with the elevated larval diets. However, the variations of survival rate and adult emergence rate were statistically significant (P < 0.05). In adults, all morphometric parameters (thoracic length, abdominal length, abdominal width, and wing length) significantly increased with elevating larval diets levels (except for thoracic width) along with the biting frequency, fecundity, and survival rate (P < 0.05) of adult females. The VC also denoted significant variations (F 4,14 = 24.048; P < 0.05) with the larval diet concentration, whereby the highest VC of 196.37 was observed at 10% treatment. CONCLUSION: Larval food availability has a significant influence on the adult fitness and thus may affect the incidence of dengue due to variations in the VC of Ae.

Corrigendum to "Larvicidal Potential of Five Selected Dragonfly Nymphs in Sri Lanka over Aedes aegypti (Linnaeus) Larvae under Laboratory Settings".

[This corrects the article DOI: 10.1155/2018/8759459.].