Browsing by Author "De Silva, N."

Now showing 1 - 3 of 3

Efficacy of Allium cepa test system for screening cytotoxicity and genotoxicity of industrial effluents originated from different industrial activities
(Springer International Publishing., 2015) Pathiratne, A.; Hemachandra, C.K.; De Silva, N.
Efficacy of Allium cepa test system for screening cytotoxicity and genotoxicity of treated effluents originated from four types of industrial activities (two textile industries, three rubber based industries, two common treatment plants of industrial zones, and two water treatment plants) was assessed. Physico-chemical parameters including the heavy metal/metalloid levels of the effluents varied depending on the industry profile, but most of the measured parameters in the effluents were within the specified tolerance limits of Sri Lankan environmental regulations for discharge of industrial effluents into inland surface waters. In the A. cepa test system, the undiluted effluents induced statistically significant root growth retardation, mitosis depression, and chromosomal aberrations in root meristematic cells in most cases in comparison to the dilution water and upstream water signifying effluent induced cytotoxicity and genotoxicity. Ethyl methane sulphonate (a mutagen, positive control) and all the effluents under 1:8 dilution significantly induced total chromosomal aberrations in root meristematic cells in comparison to the dilution water and upstream water indicating inadequacy of expected 1:8 dilutions in the receiving waters for curtailing genotoxic impacts. The results support the use of a practically feasible A. cepa test system for rapid screening of cytotoxicity and genotoxicity of diverse industrial effluents discharging into inland surface waters.
Human intestinal nematode infections in Sri Lanka: A scoping review
(Public Library of Science, 2024-12) Jayakody, N. K.; Silva, A.; Wickramasinghe, S.; De Silva, N.; Siribaddana, S.; Weerakoon, K. S.
BACKGROUND Sri Lanka, an island located in South Asia, once experienced a notable prevalence of human intestinal nematode infections (HINIs). With the implementation of control programs, infection prevalence was reduced. Detailed information on prevalence, distribution and temporal trends of HINIs is limited. This review aims to explore Sri Lanka's HINI distribution, trends, diagnostics, control and challenges.METHODOLOGY We reviewed published information on HINIs in Sri Lanka in electronic databases, local journals and grey literature from inception to September 2022. Based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-Scr), a systematic strategy was used for searching, screening, reviewing and data extraction. The screening was initiated with a review of titles and abstracts using specific keywords, followed by a full-text screening based on predefined eligibility criteria. A total of 105 studies were included in the review, with 28 selected for pooled prevalence analysis.PRINCIPAL FINDINGS The first nationwide survey in 1924 reported a hookworm infection prevalence of 93.1%. By 2017, soil-transmitted helminth (STH) infection prevalence across the island was 0.97% (ascariasis-0.45%, trichuriasis-0.25%, and hookworm infection-0.29%), and the enterobiasis prevalence between 2003 and 2017 ranged from 0% to 42.5%. Strongyloidiasis had been understudied, with a prevalence of 0.1% to 2%. Over the past two decades, the islandwide pooled HINI prevalence was 13.3%. Within specific demographics, it was 6.96% in the general community, 33.4% in plantation sector, and 11.6% in slum communities. During the colonial period, hookworm infection was the commonest HINI, but ascariasis is now more prevalent. The prevailing data relied solely on microscopy, often utilising single stool smears. Mass deworming programs were widely pursued in the first half of the 20th century, initially targeting antenatal women and schoolchildren, and now focusing on specific community groups. National surveys continue monitoring the three main STH infections.CONCLUSIONS The significant reduction in STH prevalence in the country over the past ten decades highlights the effectiveness of public health interventions, particularly mass deworming programs. Despite the success, STH prevalence disparities persist in vulnerable populations like plantation and slum communities, where hygiene and living conditions continue to pose challenges. Reliance on single stool smear microscopy highlights the need for more sensitive diagnostics to better assess infections. Fluctuating enterobiasis prevalence and limited strongyloidiasis data underscore the importance of continued surveillance and targeted interventions for sustained control and eventual elimination. Sri Lanka's experiences and control measures offer valuable insights for low-income countries in South Asia and beyond, particularly in managing HINIs with limited resources.
Risk factor analysis of cutaneous leishmaniasis in Sri Lanka through a nationwide survey
(American Society of Tropical Medicine and Hygiene, 2024) Dewasurendra, R.; Samaranayake, N.; Silva, H.; Manamperi, N.; Senerath, U.; Senanayake, S.; De Silva, N.; Karunanayake, P.; Zhou, G.; Karunaweera, N.
Leishmaniasis in Sri Lanka was first reported in the early 1990s. Cutaneous leishmaniasis (CL) cases have markedly increased in recent years, demanding due attention from health authorities. The spatial distribution of CL is not homogeneous. This case-control study investigated factors that may contribute to this heterogeneous distribution through a nationwide study. Information on sociodemographic, economic, and environmental characteristics was collected from study participants (cases, n = 303; controls, n = 2,762). All individuals were followed up for 3 years, and signs of CL or associated complications were recorded. Differences in possible risk factors between cases and controls were analyzed. Individuals <18 years old, electricity supply, spending >2 hours outdoors, visiting jungles/water bodies, and living near CL patients were identified as risk factors. Household members of 1.3% of cases, 2.3% of controls residing within a perimeter of 500 m from a patient, and 0.8% of controls living beyond 2 km from a case developed CL. Thus, CL in Sri Lanka appears intertwined with living environment and host behavior. Common environmental factors may be responsible for the higher risk of CL in individuals living in close proximity to CL patients. This may at least partly explain the clustering of CL cases in selected areas of the country.