Bio-economy offers a beneficial solution for sustainable development by rationalising the use of financial and human resources to improve productivity and environmental stewardship. The citrus family encompasses various plant species known for their antimicrobial properties, and different parts of these plants have been used in traditional Sri Lankan medicine for an extended period. However, information on the antibacterial efficacy of two indigenous citrus plants in Sri Lanka, Citrus crenatifolia and Citrus reticulata, is limited in the literature. Additionally, antibiotic resistance in bacterial pathogens is a global challenge that poses a significant threat to public health, highlighting the need for effective alternative strategies. The present study was conducted to investigate the antimicrobial properties and phytochemical composition of C. crenatifolia and C. reticulata. Active phytochemicals present in the fruit peels were extracted using an aqueous reflux method. The antimicrobial properties of the peel extracts were assessed using the agar well diffusion method against six common pathogens: Staphylococcus aureus, Pseudomonas aeruginosa, Proteus mirabilis, Klebsiella pneumoniae, Escherichia coli, and Enterococcus faecalis. A 0.5 McFarland standard was used to standardise the bacterial inoculum, and double-distilled water served as the negative control. Diameters of inhibition zones were measured after incubation, and statistical analysis was performed using SPSS version 25. The independent sample t-test revealed a significant difference between the mean values of the control and both peel sample extractions against the selected pathogens (p < 0.05). However, no statistically significant difference in antimicrobial activity among the six microbes was observed for C. crenatifolia peel extract according to the one-way ANOVA test (p > 0.05), whereas a statistically significant difference was found for C. reticulata peel extract (p < 0.05). Tukey’s post hoc analysis for C. reticulata indicated that the mean diameters of inhibition zones for Staphylococcus aureus differed significantly from those of Pseudomonas aeruginosa (p = 0.044) and Klebsiella pneumoniae (p = 0.049). The antibacterial activity of both C. crenatifolia and C. reticulata is supported by the presence of phytochemicals such as alkaloids, steroids, flavonoids, phenols, and tannins, which may act synergistically. These findings highlight the potential of these citrus peel extracts as valuable sources of antimicrobial agents, warranting further investigation to elucidate their specific mechanisms of action and potential applications in microbial control.

Canine dirofilariasis is caused by Dirofilaria, a type of filarial parasite that can also infect humans and is becoming a growing concern in Sri Lanka. Previous studies have noted that Sri Lanka has some of the highest numbers of dirofilariasis cases in Asia. This study was aimed at detecting Wolbachia bacteria—which are found inside Dirofilaria parasites—using molecular methods and also at identifying which Dirofilaria species are present in dogs in the Colombo District, Sri Lanka. Blood was collected from 368 dogs of various breeds between May and December 2025. Of these, only 35 samples (9.51%) tested positive for microfilaria using a microscope. These samples were then analyzed using DNA extraction and PCR with both general Dirofilaria and species-specific primers. At the same time, samples were also screened for Wolbachia, a bacterium that is important for Dirofilaria survival and reproduction, using Wolbachia-specific primers (wsp). Of the 35 microfilaria-positive samples, 18 (51.43%) were positive for Dirofilaria, and of those 18, only three (16.67%) were positive for Wolbachia. Among the Dirofilaria-positive samples, one (5.56%) was identified as Dirofilaria immitis, 11 (61.11%) as Dirofilaria repens, and three (16.67%) as Dirofilaria asiatica; a few samples did not match any of the species-specific primers. The PCR products for both Dirofilaria and Wolbachia were verified by gel electrophoresis and sequencing. The sequence results showed the presence of D. repens and D. asiatica in dogs. Importantly, this is the first molecular evidence of D. immitis in Sri Lanka and the first molecular identification of Wolbachia in Dirofilaria species in the country. The study also found that both D. repens and D. immitis can infect the same dog. These findings provide new information about canine dirofilariasis in Sri Lanka and highlight the need for Wolbachia-targeted parasite control and accurate molecular diagnosis to guide treatment and control efforts.

BackgroundDirofilariasis is a vector-borne parasitic infection caused by filarial nematodes belonging to the genus Dirofilaria. Sri Lanka has reported the highest prevalence of human dirofilariasis cases in Asia. Molecular-based detection of Dirofilaria vector species has not yet been conducted in Sri Lanka, which could provide more sensitive information by directly detecting and analyzing genetic material. The present study aimed to analyze the distribution of canine dirofilariasis and to determine the Dirofilaria vector species in Gampaha district, Sri Lanka, using molecular-based techniques.MethodsMosquito sampling (n=300) was performed from October to December 2024 from different sites in Gampaha district. The gut of the mosquitoes was dissected. Genomic DNA extraction followed by PCR was performed with specific primers for Dirofilaria species. The blood samples of different dog breeds (n=500) were also collected from the Gampaha district, and they were subjected to DNA extraction, PCR amplification, and sequencing. The data were analyzed by bioinformatics tools.ResultsAnalysis of the sequence data confirmed the first molecular detection of the dirofilariasis vector in Sri Lanka; Armigeres subalbatus as the potential vector mosquito for Dirofilaria repens and Dirofilaria asiatica n. sp. The sequence of D. repens recorded from Sri Lanka is not available in the literature/or any database, and the sequence of D. repens was also determined. Further, in different dog breeds, the infection rate of microfilariae was found to be different, and the Rottweiler breed was recorded with the highest infection rate. D. repens and D. asiatica n. sp. were found in dog blood samples. The phylogenetic analysis revealed that the query sequence of the D.repens parasites isolated from the present study showed considerable homology and proximity to the D. repens recorded from India.ConclusionArmigeres subalbatus is the vector mosquito for D.repens and D.asiatica n. sp., which caused canine dirofilariasis in the Gampaha district of Sri Lanka. No other mosquito species were identified as potential vectors of Dirofilaria species in the study area. This is, to our knowledge, the first D. repens sequence found in the Gampaha district, Sri Lanka. The present study findings provide very important insights for targeted vector control programs for Dirofilaria parasites in Sri Lanka.

Parasitic diseases remain a major global health burden, particularly in tropical and low-resource regions, where limitations in early diagnosis and effective therapeutics contribute to high morbidity and mortality. Emerging evidence highlights noncoding RNAs (ncRNAs) as critical regulators of host-parasite interactions, offering novel opportunities for diagnosis, prognosis, and targeted therapy. However, most of these findings are derived from in vitro experiments and preclinical models with limited validation in clinical settings. This review comprehensively examines the roles of microRNAs (miRNAs), small interfering RNAs (siRNAs), and long noncoding RNAs (lncRNAs) in the diagnosis and treatment of major parasitic diseases, including malaria, leishmaniasis, trypanosomiasis, Chagas disease, helminthic infections, cryptosporidiosis, and scabies. Distinct miRNA expression profiles are associated with disease presence, severity, and clinical outcomes, positioning them as promising noninvasive biomarkers detectable in body fluids. Specific miRNAs such as miR-223, miR-155, miR-145, and miR-3158 modulate immune responses, inflammation, and parasite survival across multiple infections. Beyond diagnostics, miRNAs actively participate in disease pathogenesis and host defense, enabling therapeutic modulation of immune pathways. siRNA-based approaches further demonstrate therapeutic potential through RNA interference-mediated silencing of essential parasite genes, successfully impairing parasite growth, viability, and development in diseases such as cystic echinococcosis, cryptosporidiosis, and scabies. Additionally, lncRNAs have emerged as key regulators of innate and adaptive immunity, influencing cytokine signaling, macrophage differentiation, and inflammatory pathways while serving as novel biomarkers for parasitic cardiomyopathies and protozoan infections. Despite promising advances, the clinical translation of ncRNA-based diagnostics and therapeutics faces significant challenges, including delivery efficiency, stability, specificity, off-target effects, and ethical considerations. Continued research, improved delivery platforms, and well-designed clinical trials are essential to harness the full potential of ncRNAs. Therefore, while ncRNA-based strategies represent a promising direction for future research, their application in parasitic disease diagnosis and therapy remains largely at an experimental level. Continued investigation of ncRNA-based methods is required to address current limitations and enable safe and effective clinical translation.

Canine dirofilariasis, caused by parasites of the genus Dirofilaria spp., is a zoonotic disease,of increasing public health concern worldwide, including in Sri Lanka. There is very limited,information on the phylogeny of Dirofilaria spp. in Sri Lanka, with few studies reporting,genetic relationships of local isolates, indicating a need for more comprehensive phylogenetic,research in the region. The present study employed molecular diagnostic techniques and,sequencing approaches to determine the species composition and genetic relationships of,Dirofilaria in dogs from the Colombo District, Sri Lanka. Blood samples (n=368) were,collected from different canine breeds in Colombo district from May to December, 2025.,Samples were subsequently subjected to genomic DNA extraction using the QIAamp DNA,Mini Spin Kit. PCR amplification was carried out using both Dirofilaria-specific primers to,amplify the 219bp region and Dirofilaria repens-specific primers to amplify the 750bp region,of the mitochondrial cytochrome oxidase subunit I gene. Positive PCR products were,confirmed using agarose gel electrophoresis and subsequently sequenced and analyzed with,BLAST, BioEdit, and MEGA 12 software to assess species identity and genetic relationships.,The accession numbers for the samples sequenced were obtained by submissions to the,GenBank database. Thirty-five samples were found as positive for microfilariae, 31.43% was,confirmed as Dirofilaria repens. The evolutionary relationship D. repens was inferred using,the neighbor-joining method in MEGA 12. The evolutionary distances computed using the,Thmura- Nei were used to create the phylogenetic tree. Phylogenetic reconstruction,demonstrates that all the samples (PX945284, PX956944, PX945286, PX945287, PX945291,,PX956943, PX945292, PX956945, PX945298, PX945300, PX945299, SUB15981968 seq1),were clustered with Dirofilaria repens clade. While the dataset confirmed a high degree of,sequence conservation within the species, topological analysis showed that significant intra-,species heterogeneity was divided into three lineages. PX945287, PX945291, PX956943, and,PX945292 illustrated an ancestral lineage with reference sequences such as D. repens from,Germany, D. repens from Japan, and D. repens from Slovakia, representing the stable,,dominant circulating genotype. Out of D. repens positive samples, 36.36% formed a distinct,sub-cluster associated with D. repens from India and D. repens from Sri Lanka, suggesting,the presence of distinct micro-evolutionary variants within the Sri Lankan landscape.,Additionally, PX956945, PX945298, PX945300, and PX945299 clustered with the reference,sequence, D. repens from Italy, confirming the phylogeographic connection among different,geographical areas in the world. The low genetic divergence observed within the,phylogenetic tree highlights the conserved nature of D. repens while showing the narrow,genetic diversity within the local population. These findings provide special molecular,observations into the epidemiology of dirofilariasis, genetic variations of D. repens, and,transmission dynamics of the disease in Sri Lanka.

Mosquitoes, notorious for their deadly impact as disease vectors, also hold economic value owing to their roles in disease transmission. The present study focuses on the importance of understanding mosquito gut microbiota for implementing innovative vector control strategies, thereby mitigating disease transmission. The study was conducted in the Gampaha Medical Office of Health (MOH) area of Sri Lanka with the focus of elucidating the microbial diversity within the midgut of Culex quinquefasciatus, a crucial step to support ongoing paratransgenesis efforts. Sampling was performed by utilizing standard mosquito sampling techniques and their midgut homogenates were plated on Plate Count Agar to isolate bacteria, which were then identified through biochemical tests. Subsequently, the most abundant bacterial families were subjected to DNA extraction, PCR amplification, and gene sequencing for species identification. The study revealed the presence of four bacterial families (Staphylococcaceae, Streptococcaceae, Neisseriaceae, and Moraxellaceae) in adult mosquitoes, while larvae harbored an additional family, Micrococcaceae. Interestingly, 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), indicating similar bacterial flora across mosquito life stages and geographical locations. Of particular interest is the identification of Lysinibacillus sphaericus, a bacterium with potential for paratransgenesis applications. Given the high mosquito density in the study area, leveraging paratransgenesis for Cx. quinquefasciatus control is recommended. Furthermore, insights into gut microbes could inform the integration of gut microflora from modified strains into existing Sterile Insect Technique (SIT) and Incompatible Insect Technique (IIT) approaches in Sri Lanka.

BackgroundProper 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.MethodsA 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.ResultsThe 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.ConclusionEven 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.

The pool of microbiota associated with mosquito breeding habitats varies with the habitat type and its characteristic features. The pool of microbiota in a given mosquito breeding habitat can include free living, symbiotic, noncompetitive, parasitic, predatory, and toxin producing species. However, in Sri Lanka the studies on the microbiota associated with mosquito breeding habitats are scarce. The present study was conducted to identify microbiota species/taxa associated with a variety of mosquito breeding habitats in selected areas of the Kurunegala district in Sri Lanka to determine the relationship, if any, the microbiota has with mosquito larvae breeding. A total of 44 microbiota species/taxa belonging to 10 phyla, namely, Bacillariophyta, Charophyta, Chlorophyta, Cyanobacteria/Cyanophyta, Ochrophyta/Heterokontophyta, Amoebozoa, Euglenozoa, Ciliophora, Arthropoda, and Rotifera were identified. Vorticella microstoma (Ciliophora) showed a constant occurrence frequency in rice field habitats occupied mainly by Culex tritaeniorhynchus while the rest of the species had an accidental or rare frequency of occurrence. Nineteen species/taxa were identified as common species. Trophont stages of Vorticella microstoma and Zoothamnium spp. were found attached to the cuticle of mosquito larvae but only V. microstoma caused a lethal effect. The autotrophic protist, Euglena geniculate, Closterium spp., and Pinnularia spp. served as the diet items to mosquito larvae. The majority of the microbiota identified had no observable effect on mosquito larvae breeding.

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 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). Graphical abstract

BACKGROUND:Larval and adult mosquito stages harbor different extracellular microbes exhibiting various functions in their digestive tract including host-parasite interactions. Midgut symbiotic bacteria can be genetically exploited to express molecules within the vectors, altering vector competency and potential for disease transmission. Therefore, identification of mosquito gut inhabiting microbiota is of ample importance before developing novel vector control strategies that involve modification of vectors.METHOD:Adult mosquitoes of Culex tritaeniorhynchus, Culex gelidus, and Mansonia annulifera were collected from selected Medical Officer of Health (MOH) areas in the Gampaha district of Sri Lanka. Midgut lysates of the field-caught non-blood-fed female mosquitoes were cultured in Plate Count Agar medium, and Prokaryotic 16S ribosomal RNA partial genes of the isolated bacteria colonies were amplified followed by DNA sequencing. Diversity indices were used to assess the diversity and richness of the bacterial isolates in three mosquito species. The distribution pattern of bacterial isolates between different mosquito species was assessed by Distance-Based Redundancy Analysis (dbRDA).RESULTS:A total of 20 bacterial species (Staphylococcus pasteuri, Bacillus megaterium, Staphylococcus cohnii, Pantoea dispersa, Staphylococcus chromogenes, Bacillus aquimaris, Staphylococcus arlettae, Staphylococcus sciuri, Staphylococcus warneri, Moraxella osloensis, Enterobacter sp., Klebsiella michiganensis, Staphylococcus hominis, Staphylococcus saprophyticus, Streptomyces sp., Bacillus niacin, Cedecea neteri, Micrococcus luteus, Lysinibacillus sphaericus, and Bacillus licheniformis) were identified. All of these species belonged to three phyla, Proteobacteria, Firmicutes, and Actinobacteria, out of which phylum Firmicutes (71.1%) was the most prominent. The least number of species was recorded from Actinobacteria. The relative distribution of midgut microbes in different mosquito species differed significantly among mosquito species (Chi-square, χ 2 = 486.091; df = 36; P ≤ 0.001). Midgut microbiota of Cx. tritaeniorhynchus and Cx. gelidus indicated a similarity of 21.51%, while Ma. annulifera shared a similarity of 6.92% with the cluster of above two species. The gut microbiota of Cx. tritaeniorhynchus was also significantly more diverse and more evenly distributed compared to Ma. annulifera. Simpson's diversity, Margalef's diversity, and Menhinick's diversity indices were higher in Cx. gelidus. Of the recorded species, P. dispersa and strains of nonpathogenic species in Bacillaceae family (B. megaterium, B. niacini, B. licheniformis, and L. sphaericus) can be recommended as potential candidates for paratransgenesis.CONCLUSION:The relative distribution of midgut microbes in different mosquito species differed significantly among the three studied adult mosquito species. The present data strongly encourage further investigations to explore the potential usage of these microbes through paratransgenic approach for novel eco-friendly vector control strategies.

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 (X2 = 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.