Journal/Magazine Articles
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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
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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 Detection, identification, and antimicrobial susceptibility of Campylobacter spp. and Salmonella spp. fromfree-ranging Nonhuman Primates in Sri Lanka(Wildlife Disease Association, 2019) Tegner, C.; Sunil-Chandra, N.P.; Wijesooriya, W.R.P.L.I.; Perera, B.V.; Hansson, I.; Fahlman, A.ABSTRACT: Infections with Campylobacter spp. and Salmonella spp. are the most frequently reported causes of human bacterial enteritis. Warm-blooded animals, including livestock, pets, and wildlife, can be carriers of the bacteria and may contaminate the environment and food products. The present study investigated the occurrence of Campylobacter spp. and Salmonella spp. in fecal pat samples from free-ranging toque macaques (Macaca sinica) and tufted gray langurs (Semnopithecus priam) collected in March-May 2015 in Sri Lanka. In 58 samples from toque macaques, Campylobacter jejuni was isolated in 10 (17%), Campylobacter coli in four (7%), and Salmonella enterica subsp. enterica serovar Virchow in two (3%). None of the bacteria were isolated in the 40 samples from tufted gray langurs. Pulse-field gel electrophoresis and multilocus sequence typing identified six profiles and four clonal complexes of C. jejuni. The isolated Campylobacter spp. showed varying susceptibility to antimicrobial substances. All Campylobacter spp. isolates were susceptible to chloramphenicol, erythromycin, florfenicol, gentamicin, and streptomycin. Four of the C. jejuni were resistant to at least one of the following: ampicillin, ciprofloxacin, nalidixic acid, and tetracycline, and one of the isolates was multidrug resistant. All four C. coli were resistant to ampicillin, whereas the two Salmonella Virchow strains were susceptible to all antibiotics tested. The presence of Campylobacter spp. and Salmonella spp. in toque macaques may have an impact on the conservation of endangered primates and public health in Sri Lanka. KEYWORDS: Campylobacter spp .; Antimicrobial resistance; PFGE; Salmonella spp; conservation; nonhuman primates.Item 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 Mycoplasma pneumoniae DNA detection and specific antibody class response in patients from two tertiary care hospitals in tropical Sri Lanka(Microbiology Society, 2018) Wijesooriya, L.I.; Kok, T.; Perera, J.; Tilakarathne, Y.; Sunil-Chandra, N.P.PURPOSE: Respiratory tract infections are a major cause of global morbidity and mortality. Pneumonia is the ninth leading cause of mortality in Sri Lanka. Atypical pathogens cause about one-fifth of community-acquired pneumonia, while Mycoplasma pneumoniae accounts for about 50 %. This study aimed to determine the seroprevalence of M. pneumoniae respiratory tract infections in Sri Lanka while attempting to understand the relationships between the serology and PCR. METHODOLOGY: Paired sera from 418 adult patients (pneumonia, n=97; bronchitis, n=183; pharyngitis, n=138) and 87 healthy controls were studied. IgM, IgG and IgA antibodies were tested by M. pneumoniae enzyme-linked immunosorbent assay (ELISA). Positive IgM and or IgG seroconversion was considered to be seropositive. M. pneumoniae DNA were tested by PCR in age and gender-matched seropositives and seronegatives. RESULTS: M. pneumoniae IgG was in 14.4 % (14/97), 6.0 % (11/183) and 1.5 % (2/138) of pneumonia, bronchitis and pharyngitis patients, respectively, whilst IgM was in 6.2 % (6/97), 1.1 % (2/183) and 0 % (0/138), respectively. Amongst the pneumonia seropositives, 64.7 % (11/17) showed IgG alone, 17.5 % (3/17) showed IgM alone and 17.5 % (3/17) showed IgM and IgG. Amongst the bronchitis seropositives, 84.6 % (11/13) had IgG alone and 15.4 % (2/13) had IgM alone. In the pharyngitis seropositives, only IgG was detected 100 % (2/2). M. pneumoniae DNA was in 52.2 % (12/23) of seropositives and 15.4 % (4/26) of seronegatives. In pneumonia or bronchitis patients, specific DNA was in 77.8 % (7/10) and 50 % (6/12) of patients, respectively. M. pneumoniae DNA was not found in pharyngitis patients. Of the seropositive PCR-negative pneumonia patients, 66.7 % (2/3) showed IgG alone and 33.3 % (1/3)showed IgM alone. In bronchitis patients, 83.3 % (5/6) showed IgG alone and 16.7 % (1/6) showed IgM alone. Of the seronegative PCR-positive patients, 16.7 % (2/12) had pneumonia and 18.2 % (2/11) had bronchitis. CONCLUSION: The serological evidence for M. pneumoniae infection in Sri Lanka comprised the following prevalences: 17.5 % (17/97), 7.1 % (13/183) and 1.4 % (2/138) in adults with pneumonia, bronchitis or pharyngitis, respectively. M. pneumoniae DNA was in 52.2 % (12/23) of seropositives and 15.4 % (4/26) of seronegatives. IgG was predominant in PCR positives and negatives.Item Application of Elisa in the diagnosis of rotavirus infections in buffalo calves(An International Journal Of Buffalo Science., 1994) Sunil-Chandra, N.P.; Mahalingam, S.The conditions for diagnosis of group A rotavirus infection in buffalo calves by enzyme linked immunosorbent assay (ELISA) were optimised in terms of type of microtitre plates, all reagents and the cut off points for positivity. Irradiated polystyrene plates were the plates of choice. The optimal dilution for the clinical samples (faecal extracts), capture and detector antibodies and the enzyme conjugate were I : 10, I : 5,000, I : 10,000 and I : 300, respectively. Further, we found that the cut off point for positivity by the screening ELISA was an optical density (OD) of ≥ 0.170 at 450 nm wave length, and for confirmation when blocking activity was ≥ 30%. 'The positivity of a faecal sample was graded as strongly positive if the PIN value was ≥2.7 by screening ELISA and ≥ 50% blocking activity in the confirmatory blocking ELISA. Samples having PIN value < 2.7 but ≥ 2. I and < 50% but ≥ 30% blocking activity were regarded as weakly positive. in addition, pre and post colostral buffalo sel'd as negative and positive control sera respectively, were selected and used for detection of antirotavlral antibodies by the blocking ELISA. 'This study establishes that the ELISA technique can be profitably used (once required parameters are defined), in the diagnosis of rotavirus infection in buffalo calves.Item MURINE GAMMAHERPESVIRUS 68: A MODEL TO STUDY DISEASES OF MAN AND DOMESTIC ANIMALS(Immunobiology of viral infections, 1995) Sunil-Chandra, N.P.; J.P. Simas.; J.K, Fazakerley.; Efstathiou, S.; Nash, A.A.The gamma herpesviruses are widely disseminated in nature causing infection and disease in man. Domestic animals including cattle, deer, sheep, horses and rodents. Murine gammaherpesvirus-68 is a natural pathogen of wild rodents. In Balb/c mice, it establishes a productive infection of epithelial cells of the lung alveoli, and a latent infection of B-Iymphocytes. As with other gammaherpesviruses, chronic infection of mice is associated with Iymphoproliferative disease (LPD) which ranges from mild to high grade lymphomas. In vitro. virus establishes persistent infection in murine myeloma B-cells in which viral DNA exists both in circular form, indicative of a latent infection and linear form, indicative of productive infection. Acyclovir can inhibit virus replication in vivo and in vitro but does not prevent latent infection in mice or reduce circular forms of viral DNA in persistently infected murine myeloma cells. CD8+ T cells are the major effector cells during acute infection. In contrast to the T-cell response which arises promptly to counter infection in the lung and spleen, antibody production (IgM) is first detectable only at 15 to 20 days. MHV-68 infection of mice provides a powerful model to study pathogenesis of gammaherpesviruses, in particular establishment and maintenance of latent infection and virus interaction with the immune system.Item A Novel murine model for studying antiviral compounds against EBV.(International Medical Press, 1994) Sunil-Chandra, N.P.; Barnes, A.G.C.; Nash, A.A.Animal models have been of great importance in for the study of herpes virus parthenogenesis by providing systems with which to investigate basic virological and immunological aspects of acute and latent infection, and also to evaluate chemotherapeutic and vaccination regimens.The best examples are those models used to study acute, latent and recurrent herpes simplex virus (HSV) infection.