Rajarata University of Sri Lanka

Leptospira borgpetersenii is a causative agent of human leptospirosis, with the potential to lead to severe disease manifestations. The first published analysis of L. borgpetersenii, performed on two strains of serovar Hardjo (L550 and JB197), suggested that the L. borgpetersenii genome is in the process of genome decay with functional consequences leading to a more obligately host-dependent life cycle. Whole genome analysis has only been carried out on few strains of L. borgpetersenii, with limited closed genomes and comprehensive analyses. Herein we report the complete, circularized genomes of seven non-typeable Leptospira borgpetersenii isolates from human leptospirosis patients in Sri Lanka. These isolates (all identified as strain ST144) were found to be nearly identical by whole genome analysis; serotyping with serogroup-specific reference antisera was unreactive, suggesting that these are members of a novel serogroup/serovar. We show that the L. borgpetersenii isolated from humans in Sri Lanka show less genomic decay than previously reported isolates: fewer pseudogenes (N = 141) and insertion sequence (IS) elements (N = 46) compared to N = 248, N = 270, and N = 400 pseudogenes, and N = 121 and N = 116 IS elements in other published L. borgpetersenii Hardjo genomes (strains L550, JB197 and TC112). Compared to previously published L. borgpetersenii whole genome analyses showing two or three VM proteins in L. borgpetersenii isolates from cattle, rats and humans, we found that all of the human L. borgpetersenii isolates from Sri Lanka, including previously reported serovar Piyasena, have four encoded VM proteins, one ortholog of L. interrogans Copenhageni LIC12339 (LA1402) and three orthologs of LIC12844 (LA0589). Our findings of fewer pseudogenes, IS elements, and expansion of the LIC12844 homologs of the PF07598 family in these human isolates suggests that this newly identified L. borgpetersenii serovar from Sri Lanka has unique pathogenicity. Comparative genome analysis and experimental studies of these L. borgpetersenii isolates offer deeper insights into the molecular and cellular mechanisms of leptospirosis pathogenesis.

Graphs serve as a bridge between algebra and numerous mathematical fields, including combinatorics, number theory, and computer science. Let Z(R) represent the set of zero-divisors in a commutative ring R. The zero-divisor graph of R, denoted by Γ(R), is an undirected graph with vertex set Z(R)∗ = Z(R) \\ {0}, where two vertices are adjacent if their product is zero. The Steiner tree and Steiner radial number are fundamental concepts in network optimization, offering cost-efficient strategies for connecting multiple points with minimal total distance. In this study, we compute the m-eccentricity of all vertices and determine the Steiner radial number of the zero-divisor graph of ℤ n . Additionally, for some positive integer m ≥ 2, we establish the existence of non-isomorphic zero-divisor graphs with Steiner radial number m. This work not only enhances the understanding of zero-divisor graphs but also provides a foundation for future studies in algebraic graph theory and network optimization.

Pleural effusion is a prevalent clinical condition; however, the occurrence of community-acquired Acinetobacter pneumoniae resulting in pleural effusion is infrequent. This case report describes a community-acquired complex pleural effusion due to Acinetobacter baumannii, which was successfully managed. A 56-year-old male patient presented to a local hospital with fever and right-sided pleuritic chest pain and was diagnosed with pleural effusion. Due to a lack of improvement after three days of intravenous meropenem antibiotics, the patient was transferred to a tertiary care hospital. Pleural aspiration confirmed a community-acquired Acinetobacter baumannii-infected complex atypical parapneumonic pleural effusion. The patient was treated with intravenous piperacillin-tazobactam, ciprofloxacin, and oral clindamycin antibiotics, along with pigtail catheter drainage, resulting in complete resolution of the condition. This report highlights the significance of early identification and effective management of atypical bacterial infections in pleural effusions.

Mango (Mangifera indica) is an economically significant fruit crop in Sri Lanka. Recently, a new disease, stem bark blackening, emerged on mango in the country, causing concerns among growers. This study aimed to identify the pathogen and explore effective in vitro strategies for its management. Field observations revealed characteristic black, irregularly shaped patches encircling the mango stems and branches. Morphological studies and phylogenetic analysis of the ITS region confirmed the pathogen as Aspergillus spp. In vitro assays demonstrated 92.4% fungal inhibition by Trichoderma viride. Among the tested plant extracts, Azadirachta indica showed the highest antifungal activity (72.3% colony size reduction compared to control). Commercial fungicides tested were less effective. In vitro biocontrol activity of T. viride and A. indica extract is more effective than conventional fungicides, highlighting their potential in integrated disease management of mango stem bark blackening disease.

BackgroundReproductive coercion and abuse (RCA) is a hidden form of violence against women, involving controlling behaviours by a partner or family member to manipulate a woman’s reproductive autonomy, either to prevent or promote pregnancy. It correlates with partner violence, unintended pregnancy, contraceptive non-adherence, and poor sexual and reproductive health. However, research often oversimplifies RCA, treating it as a uniform phenomenon and neglecting its diverse manifestations. Additionally, there is scarce evidence on RCA in low- and middle-income countries. This study examines the conceptualisation and discourse surrounding reproductive coercion among health workers and women victims/survivors in Brazil, Nepal, occupied Palestinian Territories, and Sri Lanka. The main objectives include: 1) Investigating acts of reproductive coercion reported by women and health workers. 2) Exploring how health workers approach reproductive coercion in their practice. 3) Understanding the structural, institutional, and social barriers affecting victim/survivors encounters with reproductive coercion.MethodsWe conducted 62 qualitative interviews with health workers and domestic violence victims/survivors across the four countries, plus three focus groups with women in Nepal. Data were analysed thematically.ResultsThe findings reveal that reproductive coercion emerged as a form of domestic violence across all settings studied. Reported acts of coercion and violence by both women and health workers included attempts to force pregnancy against a woman's wishes and to hinder contraceptive use, driven by jealousy or the desire to promote pregnancy. Perpetrators, mainly husbands and family members (particularly in-laws in Nepal and Sri Lanka), employed various coercive behaviours such as pressure, decision-making control, threats (e.g., leaving the partner or violence), verbal harassment, and physical violence. The analysis also underscored broader structural and social challenges constraining women's reproductive choices and health workers' responses, encompassing religious beliefs surrounding contraception and abortion, cultural norms regarding son preference (notably in Nepal), and restrictive health policies concerning abortion and spousal consent for family planning (observed in Nepal and Sri Lanka).ConclusionsThe study emphasises the necessity for further research to comprehensively understand acts of reproductive coercion and abuse and guide health workers in effectively addressing this issue.

Abstract This study investigated the biotransformation of three different plastic surfaces, polypropylene (PP), polyvinyl chloride (PVC) and polyethylene (PE), by anaerobic digestion (AD) system microorganisms under mesophilic conditions. For that, a laboratory-scale AD system was established and plastics were immersed in the sludge for a 50-day incubation period, measured for any significant mass loss. Statistical analysis showed a significant mass loss (p < 0.05) in PVC pieces with a 1.1 ± 0.16 mg average reduction, while PP and PE didn’t show any significant mass loss. Raman spectroscopy analysis revealed temporarily increasing novel peaks in PVC at 1729 cm − 1 corresponding to C = O stretching vibrations. This was considered significant and compared against an unchanged marker of PVC, revealing a newly identified peak that has not been documented in prior studies of this material. PP also revealed temporarily increasing novel peaks in the spectral range of C = C stretching vibrations in the region of 1512 cm − 1 . Atomic force microscopy (AFM) analysis of PVC showed a reduction in average roughness amplitude from 100 nm to 90 nm in 30 days and 65nm to 50 days revealing surface biotransformation. Phase-contrast microscopy further confirmed surface embrittlement across all plastics. Four bacterial species that were associated with plastic biotransformation were isolated and characterized using 16s rRNA molecular marker gene based identifications as Pseudomonas fluvialis , Bacillus cereus , Proteus mirabilis and Gottfriedia luciferensis . In conclusion, this study suggests that, the changes to overall surface of the plastics and newly observed biodegradation of PVC suggesting a biotransformation leading to biodeterioration, by AD system microorganisms.

We aimed to compare the pattern of snakebites and the pre-hospital practices of snakebite victims during, before, and after the COVID-19 period in a region of Sri Lanka with a high snakebite incidence. Data were extracted from the Anuradhapura snakebite cohort from March 2018 to October 2023. The cohort recruits all snakebite patients (>16 years) admitted to the Teaching Hospital, Anuradhapura. For this study, data from pre-COVID (March 2018-October 2019), COVID (March 2020-October 2021), and post-COVID (March 2022-October 2023) periods were analysed. There were 1141, 1312, and 1375 patients in the Pre-COVID, COVID and Post-COVID groups. Authenticated Hypnale hypnale bites increased during COVID (454/784, 58%) and post-COVID (501/849,59%) compared to pre-COVID (234/658, 36%), while Daboia russelii bites decreased during COVID (210/784, 27%) and post-COVID (205/849, 24%) compared to pre-COVID (259/658, 39%). The proportion of home garden bites increased during post-COVID (560/1375, 41%) compared to pre-COVID (378/1141, 33%) and COVID (416/1312, 32%). The percentage of patients who intentionally delayed hospital admission was greater in post-COVID (26%) compared to groups pre-COVID (18%) and COVID (16%). The percentage who sought native treatment before hospital admission was greater post-COVID (15%) compared to pre-COVID (6%) and during COVID (7%), as was the application of tourniquets as first aid post-COVID (37%) compared to pre-COVID (22%) and COVID (22%). During the COVID-19 pandemic, the rate of patients leaving the hospital against medical advice rose to 4%, up from 3% in the pre-COVID period. This trend continued to increase after the pandemic. During and after the COVID-19 pandemic, H. hypnale cases increased and D. russelii bites decreased, coinciding with shift of snakebites from farmlands to home gardens. More patients delayed hospital treatment, used harmful first aid, or left against medical advice during and after the COVID-19 pandemic.

Cutaneous leishmaniasis is a neglected tropical disease affecting humans worldwide. Leishmania donovani is the causative agent of cutaneous leishmaniasis in Sri Lanka, whereas it typically causes visceral leishmaniasis in other regional countries. Identifying pretreatment innate immune responses may offer insights into diverse disease manifestations. We studied lesion biopsy specimens from 103 cutaneous leishmaniasis patients. Total leucocytes, keratinocyte activation, and the distribution of Langerhans cells were semi-quantified using CD45, Osteopontin, and CD1a immunohistochemistry markers. M1/M2 macrophage polarisation was assessed using CD68, HLA-DR, and CD163 immunohistochemistry markers and quantified via open-source image analysis. Langerhans cell distribution was significantly higher in early lesions (p = 0.017), whereas activated keratinocytes were more prevalent in late lesions (p = 0.004). Total leucocyte count showed no significant association with clinicopathological parameters. Sixty-six patients (64.1%) had M1-dominant macrophage profiles. Macrophage polarisation type was significantly associated with treatment outcome (p = 0.048). Among 17 patients with exclusively M2-dominant profiles, 15 (88.2%) required prolonged Sodium Stibogluconate treatment for complete healing. Our findings suggest that early innate immune responses, particularly M1 macrophage polarisation, keratinocyte activation, and Langerhans cell involvement, contribute to treatment success in Sri Lankan cutaneous leishmaniasis caused by L. donovani , highlighting localised mechanisms of protective immunity.