Larvicidal activity of the pericarp extract of Garcinia mangostana against dengue vector Aedes aegypti in Sri Lanka

Objective:To assess the larvicidal activity of mangosteen(Garcinia mangostana)against larval stages of Aedes aegypti mosquitoes.Methods:A crude extract was prepared in ethanol from powdered mangosteen pericarps.A concentration gradient(0.01-4.92 g/L)was prepared from the stock solution.Seven batches of 25 third instar larvae of Aedes aegypti were used for larval bioassays.Larval mortality rates were observed after one and 24 hours.Cholesterol and total lipid contents in 20 randomly selected dead larvae at each trial were assessed by colorimetric method.The experimental setup was repeated five times.The General Linear Model and Probit analysis were used to evaluate the relationship of mortality with cholesterol level,total lipid level and cholesterol to total lipid ratio.Results:The percentage mortalities significantly varied with different concentrations(F_(7,32)=385.737;P<0.001).The LC50 and LC99 values were(0.041±0.006)g/L and(10.616±1.758)g/L,respectively after 24 hours.There was no mortality recorded within the one-hour exposure time.Only the cholesterol content(F_(5,24)=173.245;P<0.001)in larvae exposed to different concentrations denoted a significantly decreasing trend within 24-hour exposure.Larvae that were exposed to the lowest concentration(0.55 g/L)showed a higher cholesterol level(22.67±1.33)μg.Conclusions:The Garcinia mangostana extract acts as an effective sterol carrier protein inhibitor that inhibits cholesterol uptake in Aedes aegypti mosquitoes.Hence,it could be explored for use as a key source for the development of an environment-friendly plant-based larvicide.

COVID-19-induced anxiety,depression and stress among healthcare professionals in Sri Lanka

Objective:To assess the degree of anxiety,depression and stress due to the COVID-19 epidemic among healthcare professionals in Sri Lanka.Methods:Healthcare professionals from 6 selected government and private hospitals located in Gampaha District were recruited for the study.The socio-demographic factors,knowledge and attitudes of healthcare professionals on COVID-19 was collected through a self-administered questionnaire,while Depression,Anxiety and Stress Scale score was used to assess the psychological wellbeing.Descriptive statistics and binary logistic regression techniques were used for data analysis.Results:Totally 324 healthcare professionals were included and the respondents had a high overall level of knowledge towards COVID-19.Twenty-five percent of the respondents had different levels of anxiety,while 10.8%had mild depression,and 4.6%had moderate depression.Interestingly,40.4%of the respondents had mild stress,and 11.1%had moderate stress.Young people(20-35 years),medical laboratory technologist and nursing officer,being quarantined,having a SARS-CoV-2-infected family member,involvement in COVID-19 patient care,and limited availability of personal protection equipment,were recognized as significant risk factors associated with anxiety,depression and stress.Conclusions:The healthcare professionals are high-risk groups to experience psychological impacts from COVID-19.Continuous monitoring and implementing appropriate intervention activities and provision of counseling support are highly recommended.

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.