Browsing by Author "Ranasinghe, Koshila"

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Diversity and species composition of microbiota associated with dengue mosquito breeding habitats: A cross-sectional study from selected areas in Udapalatha MOH division, Sri Lanka
(Wolters Kluwer Medknow publications, 2023) Kumari, Yashoda; Amarasinghe, Deepika; Ranasinghe, Koshila
Objective: To determine the diversity of microbiota associated with different breeding habitats of dengue vector mosquitoes Aedes (Ae.) aegypti and Ae. albopictus and to identify any parasitic, epibiont, pathogenic, competitive or predatory species. Methods: Sampling was performed from a variety of breeding habitats using dipping, pipetting and siphoning techniques. Microbiota in water samples were preserved using Rose Bengal solution and Lugol’s iodine, and were identified. Live samples of microbiota were kept under laboratory conditions to observe any pathogenic or parasitic microbiota interacting with larvae. Results: A total of eleven microbiota species (Canthocamptus staphylinus, Canthocamptus microstaphylinus, Parastenocaris brevipes, Lepadella ovalis, Lepadella patella, Rotatoria rotatoria, Rotatoria macrura, Asplanchna brightwelli, Trichocerca rattus, Euglena variabilis, and Flagilaria capucina) belonging to four (4) phyla (Arthropoda, Rotifera, Euglenozoa, and Ochrophyta) and 8 microbiota species belonged to four phyla (Arthropoda, Rotifera, Euglenozoa, and Ochrophyta) were identified from Ae. aegypti and Ae. albopictus breeding habitats respectively. There was a higher percentage (54.54%) of larval habitats positive for the secondary vector Ae. albopictus than through the primary vector Ae. aegypti in the Gampola urban area indicating higher possibility of transmitting the dengue virus through the secondary vector. However, no pathogenic or parasitic ciliates on mosquito larvae were encountered in the present study. Those findings may be due to sampling maingly from temporary container-type breeding habitats. Conclusions: The relative distribution of microbiota associated with mosquito species differed significantly among Ae. Aegypti and Ae. albopictus. The overall findings of this study could help in implementing novel eco-friendly vector-control strategies in the study area.
Diversity and Species Composition of Midgut Symbiotic Bacteria in Culex quinquefasciatus Mosquitoes in Gampaha District, Sri Lanka
(Wiley, 2024) Ranasinghe, Koshila; Hathnagoda, Randi; Gunathilake, Pinidi; Buddhinee, Thilini; Welgama, Pabasara; Gunarathna, Hasini; Perera, Harshani
Mosquitoes, notorious for their deadly impact as disease vectors, also hold economic value due to their role in disease transmission. This study focuses on understanding mosquito gut microbiota as a foundation for innovative vector control strategies aimed at reducing disease spread. Conducted in the Gampaha Medical Officer of Health (MOH) area in Sri Lanka, the research aimed to explore microbial diversity within the midgut of Culex quinquefasciatus, an essential step to support ongoing paratransgenesis efforts. Sampling was conducted using standard mosquito collection techniques, and bacterial isolates from midgut homogenates were cultured on Plate Count Agar and identified through biochemical testing. The most abundant bacterial families were further analyzed using DNA extraction, PCR amplification, and gene sequencing for species-level identification. The study identified four bacterial families (Staphylococcaceae, Streptococcaceae, Neisseriaceae, and Moraxellaceae) in adult mosquitoes, with an additional family, Micrococcaceae, found in larvae. Notably, the relative distribution of midgut bacteria varied significantly among field-caught larval and adult strains from different study areas (chi-square = 1.673; P < 0.05), suggesting a consistent bacterial flora across mosquito life stages and geographic locations. A key finding was the detection of Lysinibacillus sphaericus, a bacterium with strong potential for use in paratransgenesis. Given the high mosquito density in the region, implementing paratransgenesis for Cx. quinquefasciatus control is recommended. Additionally, understanding gut microbial composition may enhance integration of modified microbiota into existing Sterile Insect Technique (SIT) and Incompatible Insect Technique (IIT) strategies in Sri Lanka.
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
(2023) Udayanga, Lahiru; Sahana, Loganatahan; Perera, Ayesha; Ranasinghe, Koshila; Ranathunge, Tharaka
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 sociodemographic 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.