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Item Exposure to environmentally relevant concentrations of acetaminophen increases the vitellogenin expression in juvenile Danio rerio (zebrafish)(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Ishara, A. A. A. P.; Perera, K. D. C.; Gunathilaka, N.; Gunasekera, D.; Wickramasinghe, P. M. T. B.; Rajapaksa, G.Non-Steroidal Anti Inflammatory Drug acetaminophen has become the most common pharmaceutical pollutant in aquatic ecosystems. Recently a non-classical pathway of endocrine disruption is suggested with acetaminophen. Early life stages account for a significant level of hormone-regulated development therefore, it is important to assess whether early life exposure to acetaminophen could result in endocrine disruption in aquatic organisms. Vitellogenin (Vtg) is an egg precursor protein produced in response to estrogen and serves as a reliable molecular marker to assess the xenoestrogen-induced endocrine disruption. Therefore, this study was carried out to investigate the effects of long-term juvenile exposure to environmentally relevant concentrations of acetaminophen on vitellogenin expression in model organism, zebrafish (Danio rerio). Zebrafish of 25 days post fertilization were maintained under environmentally relevant acetaminophen concentrations of 10 μg/L, and 75 μg/L, and in control tanks for 60 days in triplicate with 18 fish in each tank. Vtg-1, the most predominant type of Vtg mRNA produced in zebrafish liver was analyzed using qRT-PCR with β-actin as the housekeeping gene. Furthermore, hepatic vitellogenin expression has been observed with hematoxylin and eosin staining of zebrafish hepatic sections. According to the results, acetaminophen-exposed zebrafish showed higher Vtg-1 gene expression than the fish of control treatment. 10 μg/L acetaminophen showed the highest Vtg-1 expression followed by 75 μg/L of acetaminophen in fish. Hematoxylin and eosin staining of the liver of male zebrafish from control treatments appeared eosinophilic indicating the absence of Vtg while hepatocytes of control female fish were more basophilic indicating Vtg expression. However, under 10 μg/L of acetaminophen exposure, male and female fish hepatocytes appeared more basophilic than the control treatment indicating acetaminophen-induced Vtg secretion. However, 10 μg/L concentration shows a higher basophilic nature compared to 75 μg/L, especially in female fish. The lowered Vtg expression in 75 μg/L can be due to the increased hepatotoxicity caused by the higher doses of acetaminophen which overrides the physiological activity in acetaminophentreated fish, dilated capillaries were observed compared to fish in the control treatment. It has been demonstrated that estrogenic xenobiotics stimulate the synthesis of Vtg by acting on the liver's estrogen receptors. Increased Vtg -1 mRNA in low acetaminophen concentration as shown in qRT- PCR and liver histopathology postulate an “estrogen-like activity of acetaminophen”. The results indicate that acetaminophen has the potential to increase vitellogenin expression in zebrafish even under environmentally relevant low concentrations indicating an endocrine disruption effect during juvenile exposure.Item An automated machine learning approach to detect Leishmania parasites: An alternative tool for Leishmaniasis disease diagnosis(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Amarathunge, J. A.Y.S.; Gunathilaka, N.; Sudusinghe, H.; Nilaweera, T. H. W. T.Leishmaniasis is a neglected tropical disease caused by a protozoan parasite that poses a significant threat to human life on a global scale. Leishmaniasis is endemic in 99 countries with more than 12 million people infected. Despite being the primary diagnostic method, microscopy needs technical expertise. Since there is no systematized surveillance programme for Leishmaniasis in Sri Lanka, trained personnel to be involved in disease diagnosis by microscopy is limited and only a few health care institutions have such trained individuals. Therefore, this study aimed to study the feasibility of using an automated machine learning programme to detect Leishmania parasites in the microscopic fields. A machine learning model is built on the TensorFlow framework and employs a combination of Convolutional Neural Networks for feature extraction and classification. A total of 150 views of 75 microscopically positive slides for Leishmania parasites (amastigotes) were photographed. Slides that were negative for the parasites were also captured in similar numbers. All captures were fed into the model and tested with 25 positive and negative fields. The machine learning model developed in this study detected 94.1% (n=34) negative fields as negative for Leishmania parasites. Of the positive fields, 93.3% (n=32) of them were detected as positive for the parasites by the developed model. The model indicated 92% accuracy for the detection of Leishmania parasites in the microscopic fields. This level of accuracy can significantly enhance early detection and prompt treatment, potentially reducing the disease burden, complications, and healthcare costs in regions where resources are limited. The model’s versatility permits this approach to be adapted for the detection of other parasitic diseases in Sri Lanka which are not common at present. The proposed method would be a better alternative to disease diagnosis in low-resource settings with limited technical expertise. However, it is recommended to validate the model with more sample data to obtain a better accuracy and applicability.Item Dengue prediction modelling and development of area-specific thresholds for epidemic management in urban settings of Gampaha district, Sri Lanka(International Research and Innovation Symposium on Dengue amidst the Pandemic, 2022) Dalpadado, R.; Amarasinghe, D.; Gunathilaka, N.; Wijayanayake, A.Introduction and objectives The growing global threat of dengue in both endemic and non-endemic countries have shifted the attention to establishing an early warning system to assist in dengue control and effectively allocating scarce public health resources to manage outbreaks. Thus, the current study was designed to develop localized thresholds to aid in sustainable dengue vector control measures in three Medical Officer of Health (MOH) areas (Negombo, Wattala, Kelaniya) in the Gampaha District. Method The cross-correlation function analysis (CCF) was performed to check the effects of climatic variables (average rainfall, rainy days, average temperature, humidity) and Breteau Index (BI) with dengue case incidence from 2014 to 2019. The dengue incidence at time t, BIs with a one-month lag; Aedes aegypti; BIA(t-1), Aedes albopictus; BIB (t-1) and monthly average rainfall; RFavg (t-2), rainy days; RD (t-2), Average relative humidity; RHavg (t-2) at twomonth lag and monthly average temperature; Tavg at three-month lag were checked. Areaspecific thresholds were derived from multiple linear regression. The model was validated for the Jaela MOH area for the same period. Results Stepwise regression has excluded temperature, rainfall and BIB in urban areas and a statistically significant strong association (r= 0.775) was displayed with BIA(t-1) and RHavg(t-2). When the incidence of the cases exceeded 25, it reached an alarming situation while exceeding 44 was classified as an epidemic in urban areas. BIA>1, RHavg >85%, BIA>2; RHavg>81%, the model implies an early outbreak scenario and when BIA >3; RHavg > 88%, BI>4; RHavg>84%, BIA>5; RHavg>81%, and whenever BIA > 6; RHavg>77% it reached up to severe epidemics. The model accurately predicted all outbreaks in the Jaela MOH area. International Research and Innovation Symposium on Dengue amidst the Pandemic 63 Conclusions and recommendations The common thresholds utilized for vector control entities remain ineffective and cannot be applied throughout the country. Therefore, early warning indications can plan a prior month source reduction in a low-risk zone. In contrast, government-led source reduction programs should be maximized and an intense integrated vector control method must be implemented before it reaches an epidemic.Item Diversity of midgut bacteria in larvae and females of Aedes aegypti and Aedes albopictus from Gampaha District, Sri Lanka(Parasites & Vectors volume 14, 2021) Ranasinghe, K.; Gunathilaka, N.; Amarasinghe, L.D.; Rodrigo, W.; Udayanga, L.Abstract 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 fieldcollected 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 bacterialItem Breeding sites of Phlebotomine sand flies in cutaneous leishmaniasis disease endemic areas of the Kurunegala District in Sri Lanka(Research Symposium on Pure and Applied Sciences, 2018 Faculty of Science, University of Kelaniya, Sri Lanka, 2018) Wijerathna, T.; Gunathilaka, N.; Gunawardena, K.; Rodrigo, W.Leishmaniasis is a disease transmitted by the bite of infected female sand flies. Disease control largely depends on the knowledge on natural breeding sites of sand flies. In Sri Lanka, only limited information is available on microhabitats of immature sand flies. Therefore, the present study was conducted to identify natural breeding habitats of sand flies in three cutaneous leishmaniasis endemic areas, namely; Galgamuwa, Polpithigama and Maho in the Kurunegala District of Sri Lanka. Study areas were selected based on the number of patients reported to respective Medical Officer of Health (MOH) during the year 2013 - 2016. A preliminary survey was conducted in April 2017 and possible breeding sites were identified for the survey based on field investigations and previous literature. A breeding habitat checklist was prepared for main habitat categories. Field investigations for immature stages were conducted on a monthly basis from May 2017 - June 2018. Three soil samples were collected randomly from each potential breeding habitat and transported to the laboratory. The soil samples were divided into equal portions, and immature stages of sand flies in one portion were screened by direct microscopic examination and sugar flotation method. The rest of the soil samples were incubated at 260C and 75-80% Relative Humidity (RH) under confined laboratory conditions for adult emergence. Adult sand flies were identified using morphological identification keys. A total of 433 potential breeding sites were surveyed under 21 habitat categories. Of them, soil mounds were predominant (n=51) followed by leaf litter (n=46), termite hills (n=42) and tank/river margins (n=36). However, only four habitat types were positive for immature stages of Phlebotomus argentipes, namely; paddy fields (n=5/10), moist soil in dried tanks (n=2/12), soil beneath decaying organic matter (n=2/7) and cattle huts (n=1/23). All positive sites were enriched with organic matter containing moderate moisture levels. However, further studies are required to understand the physiochemical parameters of breeding sites and by that minimize the sand fly population through management of habitat conditions.Item Comprehensive evaluation of demographic,socio-economic and other associated risk factors affecting the occurrence of dengue incidence among Colombo and Kandy Districts of Sri Lanka: a cross-sectional study(Parasites & Vectors (2018) 11:478, 2018) Udayanga, L.; Gunathilaka, N.; Iqbal, M.C.M.; Lakmal, K.; Amarasinghe, U.S.; Abeyewickreme, W.Background: Comprehensive understanding of risk factors related to socio-economic and demographic status and knowledge, attitudes and practices (KAP) of local communities play a key role in the design and implementation of community-based vector management programmes, along with the identification of gaps in existing control activities. Methods: A total of 10 Medical Officers of Health (MOH) areas recording high dengue incidence over the last five years were selected from Colombo (n = 5) and Kandy (n = 5) Districts, Sri Lanka. From each MOH area, 200 houses reporting past dengue incidence were selected randomly as test group (n = 1000 for each district) based on the dengue case records available at relevant MOH offices. Information on socio-economic and demographic status and knowledge, attitudes and practices were gathered using an interviewer administered questionnaire. The control group contained 200 households from each MOH area that had not reported any dengue case and the same questionnaire was used for the assessment (n = 1000 for each district). Statistical comparisons between the test and control groups were carried out using the Chi-square test of independence, cluster analysis, analysis of similarities (ANOSIM) and multidimensional scaling (MDS) analysis. Results: Significant differences among the test and control groups in terms of basic demographic and socio-economic factors, living standards, knowledge, attitude and practices, were recognized (P < 0.05 at 95% level of confidence). The test group indicated similar risk factors, while the control group also shared more or less similar characteristics as depicted by the findings of cluster analysis and ANOSIM. Findings of the present study highlight the importance of further improvement in community education, motivation and communication gaps, proper coordination and integration of control programmes with relevant entities. Key infrastructural risk factors such as urbanization and waste collection, should be further improved, while vector controlling entities should focus more on the actual conditions represented by the public on knowledge, attitudes and personal protective practices. Conclusions: The design of flexible and community friendly intervention programmes to ensure the efficacy and sustainability of controlling dengue vectors through community based integrated vector management strategies, is recommended.