Journal/Magazine Articles
Permanent URI for this collectionhttp://repository.kln.ac.lk/handle/123456789/13
This collection contains original research articles, review articles and case reports published in local and international peer reviewed journals by the staff members of the Faculty of Medicine
Browse
16 results
Search Results
Item Evidence of orthohantavirus and leptospira infections in small mammals in an endemic area of Gampaha district in Sri Lanka(BioMed Central Ltd, 2022) Sunil-Chandra, N.P.; Fahlman, A.; Waidyarathna, S.; Näslund, J.; Jayasundara, M.V.M.L.; Wesula, L.O.; Bucht, G.Background: Orthohantaviruses and leptospira are emerging zoonotic pathogens of high public health significance. The epidemiology of orthohantavirus infections and leptospirosis is similar and presents related clinical pictures in humans. However, a paucity of data on actual reservoir hosts for orthohantaviruses and leptospira exists. Therefore, this study aimed at determining the occurrence of orthohantaviruses and leptospira in small mammals captured in an endemic region of Sri Lanka. Methods: Rodents and shrews were morphologically and/or genetically identified using morphological keys and DNA barcoding techniques targeting the cytochrome oxidase b subunit gene (Cytb). Lung tissues and sera were subsequently analyzed for the presence of orthohantavirus RNA using qRT-PCR. Sera of rats were tested for IgG antibodies against orthohantaviruses and leptospira. Results: Forty-three (43) small mammals representing: Rattus (R.) rattus (black rat) or R. tanezumi (Asian rat), Suncus murinus (Asian house shrew), R. norvegicus (brown rat) and Mus musculus (house mouse) were investigated. No orthohantavirus RNA was detected from the lung tissue or serum samples of these animals. Elevated levels of IgG antibodies against Puumala orthohantavirus (PUUV) and/or Seoul orthohantavirus (SEOV) antigens were detected in sera of 28 (72%) out of the 39 rats analysed. Interestingly, 36 (92%) of the 39 rats also showed presence of anti leptospira-IgG antibodies in their serum, representing dual infection or dual exposure in 26/39 (66.7%) of examined rats. Conclusions: This project targets important public health questions concerning the occupational risk of orthohantavirus infections and/or leptospirosis in an endemic region of Sri Lanka. Most rats (72%) in our study displayed antibodies reacting to orthohantavirus NP antigens, related to PUUV and/or SEOV. No correlation between the orthohantavirus and leptospira IgG antibody levels were noticed. Finally, a combination of both morphological and DNA barcoding approaches revealed that several species of rats may play a role in the maintenance and transmission of orthohantavirus and leptospira in Sri Lanka.Item Corrigendum: Association of Hantavirus infections and Leptospirosis with the occurrence of Chronic Kidney Disease of Uncertain Etiology in the North Central Province of Sri Lanka: A Prospective study with patients and healthy persons(Frontiers Media SA, 2020) Sunil-Chandra, N.P.; Jayaweera, J.A.A.S.; Kumbukgolla, W.; Jayasundara, M.V.M.L.[This corrects the article doi: 10.3389/fcimb.2020.556737]. Erratum for : Association of Hantavirus infections and Leptospirosis with the occurrence of Chronic Kidney Disease of uncertain etiology in the North Central Province of Sri Lanka: A Prospective study with patients and healthy persons [Frontiers in Cellular and Infection Microbiology. 2020;10:556737].Item Association of Hantavirus infections and Leptospirosis with the occurrence of Chronic Kidney Disease of Uncertain Etiology in the North Central Province of Sri Lanka: A prospective study with patients and healthy persons(Frontiers Media SA, 2020) Sunil-Chandra, N.P.; Jayaweera, J.A.A.S.; Kumbukgolla, W.; Jayasundara, M.V.M.L.ABSTRACT: Chronic Kidney disease of uncertain etiology (CKDu) has become a significant disease burden, affecting farming community of Sri Lanka and the exact etiology, which could be multifactorial, is not hitherto established. This study is aimed to determine the association of past hantavirus infection and leptospirosis with the occurrence of CKDu. A cohort (n = 179) of known CKDu patients living in high-CKDu prevalent areas of Anuradhapura district of Sri Lanka was compared with a group of 49 healthy, sex-matched younger blood relatives of CKDu patients (control-1) and another 48 healthy, age, and sex-matched individuals living in low-CKDu prevalent area (control-2) of the same district where same life style and climate conditions prevail. Fifty out of 179 (27.9%) CKDu patients, 16/49 (32.7%) of control-1 and 7/48 (14.6%) of control-2 were found positive for IgG antibodies to Puumala, Hantaan or both strains of hantaviruses. Hantaan strain specificity was found to be predominant in all study groups. Hantavirus IgG sero-prevalence of healthy individuals living in low-CKDu prevalent area was significantly lower compared to CKDu patients and healthy younger blood relatives living in high-CKDu prevalent areas (p = 0.03). Past hantavirus infection possesses a significant risk for the occurrence of CKDu (OR = 4.5; 95% CI-3.1-5.4, p = 0.02). In contrast, IgG seroprevalence to hantaviruses was not significantly different in CKDu patients and healthy younger blood relatives living in high-CKDu prevalent areas indicating past hantavirus infection has no association with the occurrence of CKDu or possibly, younger relatives may develop CKDu in subsequent years. Seroprevalence to leptospirosis showed no significant difference between CKDu patients and healthy controls. KEYWORDS: CKDu; chronic kidney disease; hantaviruses; leptospira; sero-prevalence. Erratum in: Front Cell Infect Microbiol. 2020;10:631515Item Epidemiology of multidrug-resistant Enterobacteriaceae in Sri Lanka: First evidence of bla KPC harboring Klebsiella pneumoniae.(Elsevier., 2020) Kumudunie, W.G.M.; Wijesooriya, L.I.; Namalie, K.D.; Sunil-Chandra, N.P.; Wijayasinghe, Y.S.BACKGROUND: Extended-spectrum β-lactamase producing Enterobacteriaceae (ESBL-PE) and carbapenem-resistant Enterobacteriaceae (CRE) are disseminated worldwide posing a serious public health concern. Although, the presence of ESBL-PE and CRE in Sri Lanka has been reported, the prevalence is unknown. This study aimed to provide up-to-date epidemiological data on multidrug-resistant Enterobacteriaceae and to characterize the molecular determinants of carbapenemase-producing Enterobacteriaceae (CPE) in Sri Lanka.METHODS: A prospective cross-sectional study was conducted at a tertiary care hospital in Sri Lanka between December 2017 and February 2018. ESBL-PE and CRE were identified by disc diffusion method. Carbapenemase production was determined by carbapenem inactivation method and the presence of selected carbapenemase genes were detected by PCR. RESULTS: Five hundred and ninety-three Enterobacteriaceae were isolated from variety of clinical samples. Overall prevalence of ESBL-PE and CRE were 26.0% (n = 154) and 9.6% (n = 57), respectively. The highest rate of ESBL-PE (30.8%) was found in urine samples, while the highest occurrence of CRE (20.8%) was seen in respiratory specimens. The most common CRE species identified was K. pneumoniae (n = 46, 80.7%), followed by C. freundii (n = 4, 7.0%), E. coli (n = 3, 5.3%), P. rettgeri (n = 2, 3.5%), E. cloacae (n = 1, 1.7%), and K. aerogenes (n = 1, 1.7%). Carbapenemase production was observed in 54 (94.7%) of CRE isolates. Fifty eight carbapenemase encoding genes were identified in 54 CPE. The most prevalent carbapenemase gene was blaOXA-48-like (n = 48, 88.9%), followed by blaNDM (n = 8, 14.8%), and blaKPC (n = 2, 3.7%). CONCLUSIONS: This study reports an alarming rate of CRE and the emergence of blaKPC harboring K. pneumoniae in Sri Lanka. The need for preventive measures is highlighted to limit the spread of these difficult-to-treat bacteria in the country. KEYWORDS: Carbapenem resistance; Carbapenemase; ESBL; Enterobacteriaceae; KPC; Sri Lanka.Item Canine Rabies and its implications for human health in Sri Lanka(Veterinary Research Institute, 2018) Ubeyratne, J.K.H.; Srikitjakarn, L.; Pfeiffer, D.U.; Kohnle, L.; Sunil-Chandra, N.P.; Chaisowwong, W.; Hemwan, P.Rabies is an endemic viral zoonotic disease in Sri Lanka. Dogs are the main reservoir and transmitter, making surveillance of canine rabies crucial for disease elimination. Sri Lanka is one of the Asian countries where human deaths from rabies have been reduced markedly, but it still remains a significant public health problem. Ninety-five percent of human cases in the country are attributed to dog bites. Human settlement patterns allow the existence of dogs. The size of the dog populations is dependent on the habitat, especially the availability of resources such as food, water, and shelter. Although most dogs are owned, many ownerless dogs are allowed to roam freely resulting in vaccination coverage in dogs is heterogeneous. Other terms for ownerless dogs, i.e., dogs which do not have an acknowledged owner include community dogs and stray dogs. Such type of ownerless dogs are more common in rural as compared to urban areas. The frequency of vaccination in ownerless dogs is below the required level. Human attitudes towards dogs, especially ideas of responsible ownership, dog-keeping practices, and other aspects of human behavior influence rabies transmission risk. Research is required to reduce existing gaps in understanding of the knowledge, attitudes, and practices of the general population regarding the need for both dog population control and for rabies vaccination. Additionally, an improved understanding of dog demography and the ecological context of dog populations is essential for increasing dog vaccination coverage, achieving more effective vaccination campaign planning, and better determining the needs of dog population management programs. In order to achieve control of and finally eliminate rabies in Sri Lanka, the epidemiology of canine rabies in the country should be studied in relation to dog ecology and social aspects of pet ownership. A well-executed rabies control program needs to be based on integrated information regarding dog populations including an understanding of relevant differences in environmental habitats, in human cultures and social strata, and in different epidemiological situations. This article examines the rabies situation in Sri Lanka with respect to trends in human and canine rabies and identifies challenges ahead for rabies elimination.Item The Effect of acyclovir on the acute and latent murine gammaherpesvirus-68 infection of mice(Sage Publishing, 1994) Sunil-Chandra, N.P.; Efstathiou, S.; Nash, A.A.Mice inoculated intranasally with murine gammaherpesvirus-68 were used to evaluate the efficacy of acyclovir (ACV) in the treatment of acute and latent infections. Effectiveness was measured by infectious virus assay of the lung (site of active replication) and infectious centre assay of spleen cells (site of latency). Intraperitoneal administration of ACV at 6-h intervals starting soon after inoculation was more effective in reducing infectious virus in the lung than was treatment with 12-hourly injections commencing 3 days post-infection.Item Pathogenesis of murine gammaherpesvirus infection in mice deficient in CD4 and CD8 T cells(American Society for Microbiology., 1993) Ehtisham, S.; Sunil-Chandra, N.P.; Nash, A.A.Murine gammaherpesvirus is a natural pathogen of wild mice. The virus infects alveolar cells and spleen cells during the primary infection and establishes a latent/persistent infection in B lymphocytes. Little is known about the immunological response to gammaherpesviruses during a primary infection. To address this issue, we investigated the pathogenesis of murine herpesvirus 68 (MHV-68) infection in mice deficient in CD4 or CD8 T-cell populations. Infection of the lung and spleen were greatly exacerbated in CD8-deficient mice, reflected by elevated virus titers in the lung and an increase in the number of infected splenocytes located around germinal centers. This finding contrasts with clearance of virus from the lung and spleen by day 12 postinfection in CD4-depleted animals. These data clearly indicate a major role for CD8 T cells in recovery from an acute MHV-68 infection. Whereas CD4 T cells fail to influence the course of infection in the lung, they do contribute to lymphoproliferation seen in the spleen (splenomegaly) during the primary infection. The significance of these results are discussed in relation to the immune response to other herpesviruses, in particular Epstein-Barr virus, with which MHV-68 shares similar molecular and biological properties.Item Leptospirosis versus hantavirus infections in the Netherlands and in Belgium, 2000 to 2014 [Letter to the editor](European Centre for Disease Prevention and Control (ECDC), 2014) Clement, J.; Van Esbroeck, M.; Lagrou, K.; Verschueren, J.; Sunil-Chandra, N.P.; Van Ranst, M.No Abstract Available. Comment on: The hanta hunting study: underdiagnosis of Puumala hantavirus infections in symptomatic non-travelling leptospirosis-suspected patients in the Netherlands, in 2010 and April to November 2011.Goeijenbierm M et al. Euro surveillance.2014;19(38):20878Item Lymphoproliferative disease in mice infected with murine gammaherpesvirus 68(American Assn. of Pathologists; Elsevier, 1994) Sunil-Chandra, N.P.; Arno, J.; Fazakerley, J.; Nash, A.A.Murine gammaherpesvirus is a natural pathogen of wild rodents. In the laboratory it establishes an infection of epithelial cells and persists in B lymphocytes in a latent form. Inbred mice chronically infected with the virus develop a lymphoproliferative disease (LPD) similar to that seen in patients infected with Epstein-Barr virus. The frequency of LPD over a period of 3 years was 9% of all infected animals, with 50% of these displaying high grade lymphomas. The incidence of LPD was greatly increased when infected mice were treated with cyclosporin A. The majority of mice used in the experiments were BALB/c, although lymphomas were detected in mice on other genetic backgrounds, ie, CBA and B10Br. Lymphomas were associated with both lymphoid and nonlymphoid tissues (liver, lung, and kidney). In all cases of lymphomas studied thus far, there was a mixed B cell (B220+ve) and T cell (CD3+ve) phenotype. The B cells were light chain restricted, indicative of a clonal origin. Variable numbers of virus genome-positive cells were detected by in situ hybridization in and around the lymphomas. In contrast, no lytic antigen-positive cells were detected, indicating that genome-positive cells were either latently infected or undergoing an abortive infection. These observations suggest that murine gammaherpesvirus-infected mice may be an important model to study the pathogenesis of LPD associated with other gammaherpesviruses, such as Epstein-Barr virus.Item Murine gammaherpesvirus 68 establishes a latent infection in mouse B lymphocytes in vivo(Microbiology Society, 1992) Sunil-Chandra, N.P.; Efstathiou, S.; Nash, A.A.Murine gammaherpesvirus 68 (MHV-68) is able to persist in spleen cells of infected mice. To determine the cell type harbouring persistent virus, spleen cells from infected animals were separated into immunoglobulin (Ig)-positive (B cell-enriched), Ig-negative (T cellenriched) and plastic-adherent (macrophage-enriched) fractions. These cells were co-cultivated with permissive BHK-21 cells in an infectious centre assay. The consistent recovery and enrichment of infectious centres in the Ig-positive fraction clearly demonstrates that B cells are a major site of virus persistence/latency. This observation indicates that MHV-68 is biologically similar to Epstein-Barr virus and other members of the B cell lymphotropic gammaherpesvirus 1 subgroup.