Browsing by Author "Gunaratna, G.P.S."

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A 9-year-old male with fever, proptosis and hemodynamic instability
(Baltimore, Md, 2021) Gunaratna, G.P.S.; Howard-Jones, A.R.; Khatami, A.; Huynh, J.; Kesson, A.M.
No abstract available
Assessment of Real Time Polymerase Chain Reaction (PCR) Assay for the Early Diagnosis of Leptospirosis in Humans
(International Postgraduate Research Conference 2019, Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2019) Uduwawala, U.M.H.U.; Manamperi, A.; Gunaratna, G.P.S.; Karunanayake, L.; Chandani, W.L.; Hapugoda, M.
Leptospirosis is the most widespread zoonotic disease worldwide having a great impact on health issues in developing countries. It is caused by a pathogenic spirochete of the genus Leptospira where humans become infected through contact with the urine of infected animals. It is often exceptionally under-recognized as the clinical manifestation mimics variety of similar disease conditions that occur in the same environmental and climatologic conditions which accentuate the importance of laboratory diagnosis of leptospirosis. At present, no hospital based facilities are available for acute confirmation of the disease. The existing practice is retrospective confirmation with serological diagnosis. Therefore, the establishment of acute phase diagnosis will help in monitoring the disease, determining when hospital admission is required and reduce case fatalities. The objective of this study was to establish and evaluate a molecular-based assay to provide laboratory confirmation of leptospirosis at the acute phase of the infection (1-5 days of fever). Patients fulfilling clinical criteria stipulated by the accepted case definition were selected for the study and patients who failed to show evidence of sero conversion were considered as true negatives. A real time Polymerase Chain Reaction (PCR) assay with targeting a 203 bp fragment in the secY gene which is conserved among pathogenic serovars of Leptospira was established using a reference DNA sample (L.interrogans serovar Icterohaemorrhagiae strain RGA). Analytical sensitivity and the analytical specificity of the assay were calculated. The accuracy of the real time PCR was determined by a panel of acute blood samples collected from laboratory confirmed leptospirosis patients (n=35) and non-leptospirosis (n=44) patients based on Microscopic Agglutination Test (MAT) and/or IgM immunochromatography. Patients who failed to give positive test results either with MAT or IgM immunochromatography were considered as true negatives. Analytical sensitivity was approximately 314 genome equivalents per reaction and analytical specificity showed no amplification of Leptospira saprophytic sp. and other micro-organisms. The assay could effectively detect Leptospira DNA from clinically diagnosed leptospirosis suspected patients with 60.0% (21/35) diagnostic sensitivity and 77.27% (34/44) diagnostic specificity. This may be attributed to some samples failing laboratory confirmation despite their collection based on clinical suspicion. Therefore, real time PCR established can be used for rapid and definitive diagnosis of leptospirosis during the acute phase of infection
Detection of pathogenic Leptospira with rapid extraction followed by recombinase polymerase amplification (RPA) and quantitative polymerase chain reaction (qPCR) assay-A comprehensive study from Sri Lanka
(Public Library of Science, 2024) Uduwawala, H.; Manamperi, A.; Gunaratna, G.P.S.; Karunanayake, L.; Ceruti, A.; Wahed, A.A.E.; Fernando, L.; Premaratna, R.; Hapugoda, M.
Leptospirosis is the most widespread zoonosis in the world. The disease is more prevalent in tropical regions where the majority of developing countries are located. Leptospirosis is considered a protean manifestation zoonosis with severity of the disease ranging from a mild febrile illness to a severe and life-threatening illness. Clinical symptoms of leptospirosis overlap with other tropical febrile illnesses. Early, rapid, and definitive diagnosis is important for effective patient management. Since Polymerase Chain Reaction (PCR)-based assays are not readily available in most clinical settings, there is a need for an affordable, simple, and rapid diagnostic test. Quantitative PCR (qPCR) and Recombinase Polymerase Amplification (RPA) were implemented at the Faculty of Medicine, University of Kelaniya, and a prospective study to evaluate RPA for diagnosis of acute phase of leptospirosis was conducted. Results indicate that RPA and qPCR were positive in 81% (98/121) of the total positive and acute clinical samples. Of the 81 positive MAT confirmed patients 60 (74%) and 53 (65%) were positive with qPCR and RPA respectively. Retrospective evaluation revealed a high diagnostic accuracy (sensitivity-70% and specificity-87%) of RPA compared to MAT as the reference gold standard. Results further suggest that there is no significant difference between the two assays, qPCR and RPA-SwiftX (P = 0.40). Laboratory procedures for the extraction and detection by qPCR in the laboratory have been optimized to obtain results within 6 hours. However, the RPA-SwiftX method under field conditions took 35 minutes. The RPA-SwiftX method could replace the qPCR which shows similar sensitivity and specificity. Therefore, RPA established under the current study presents a powerful tool for the early and rapid diagnosis of leptospirosis at point-of-care.
Diagnosis of Enterobius vermicularis infestations.
(Blackwell Scientific Publications, 2020) Gunaratna, G.P.S.; Dempsey, S.; Ho, C.; Britton, P.N.
No abstract available
Introduction of Recombinase Polymerase Amplification assay based mobile suitcase laboratory as a point of need tool to diagnose cutaneous leishmaniasis in Sri Lanka
(Sri Lanka Medical Association, 2018) Gunaratna, G.P.S.; Ranasinghe, P. H. K. I. S.; Manamperi, A.; Pathirana, N.; Pathirana, H.; Wickremasinghe, R.; de Silva, N.R.; Sooriyarachchi, M.; Ahmed, A.E.W.
INTRODUCTION AND OBJECTIVES: Cutaneous leishmaniasis (CL) caused by the vector-borne protozoan parasite is now endemic in Sri Lanka. Microscopy of Giemsa stained slit skin smears (SSS), lesion aspirates or scrapings for the presence of amastigotes, is widely used for laboratory confirmation of CL, although the reported sensitivity is low. Facilities for more sensitive culture and molecular techniques are available only in reference laboratories. A newly developed, Recombinase Polymerase Amplification (RPA) assay based Mobile Suitcase Laboratory (MSL) is a promising, molecular point of care test with high sensitivity and specificity for diagnosis of both post-kala• azar dermal leishmaniasis and visceral leishmaniasis. Objective was to assess RPA based MSL as a point of need tool to diagnose CL in Sri Lanka.METHODS: Twenty seven army personnel at Mullaitivu Army camp clinically suspected of having CL were recruited for this pilot study. Two slit skin smears and two punch biopsy specimens were obtained from each of them. Slit skin smears were stained with Giemsa in the field and examined for the presence of amastigotes and RPA was carried out at the point of collection. PCR was performed at the Parasitology Department, Sri Jayewardenepura University. RESULTS: Fifteen patients were confirmed by PCR as having CL and 14 of them were also positive by RPA based MSL conducted in the field (93.33% sensitivity). Only 3/15 were positive with microscopy of SSS (20% sensitivity). CONCLUSION: This pilot study shows RPA based MSL as a promising tool to diagnose CL at point of need.
Paradoxical lymph node reaction during treatment of scalp tuberculosis [Case report]
(Blackwell Scientific Publications., 2022) Gunaratna, G.P.S.; Howard-Jones, A.R.; Marais, B.; Britton, P.N.
No abstract available
Postinfectious Acute Cerebellar Syndromes in children: A nationally ascertained case series from Australia 2013-2018
(Littleton, 2022) Gunaratna, G.P.S.; Mohammad, S.S.; Blyth, C.C.; Clark, J.; Crawford, N.; Marshall, H.; Dale, R.C.; Jones, C.A.; Britton, P.N.; PAEDS Network
Introduction: Postinfectious acute cerebellar syndromes show a wide spectrum of acute severity and can occur with acute febrile illness or vaccine receipt. Varicella has historically been the most common cause, associated with up to 25% of cases in large cohorts. This study aimed to describe the spectrum of syndromes in a setting with high varicella vaccine coverage. Method: Data were collected on children initially identified as "suspected encephalitis" subsequently designated "not-encephalitis" at participating children's hospitals in the Paediatric Active Enhanced Disease Surveillance (PAEDS) network, Australia, as part of the Acute Childhood Encephalitis study. A comprehensive descriptive analysis was undertaken on prospectively identified, national series of children with postinfectious acute cerebellar syndromes from 2013 to 2018. Cases were classified using a previously validated severity score, and the outcome was assessed at 12 months using the Liverpool Outcome Scale score. Results: A total of 20 cases (65% were vaccinated for varicella) were included, of which 70% were subcategorized as acute cerebellar ataxia (ACA), 20% acute cerebellitis (AC), and 10% acute fulminant cerebellitis (AFC). An acute febrile illness was noted in 55% and none were related to varicella or were temporally related to varicella vaccination or other childhood vaccines. A subset (total of 7 children) followed up at 12 months all showed reduced Liverpool Outcome Scale scores. Discussion: The study provides an overall description of this uncommon spectrum of neurologic syndromes and shows the infrequency of varicella zoster virus as a cause in a vaccinated population.
Sri Lanka’s journey through antimicrobial resistance – gaps and gains
(Sri Lanka Medical Association, 2024) Chandrasiri, N.S.; Vidanagama, D.S.; Gunaratna, G.P.S.; Elwitigala, J.P.; Patabendige, C.G.U.A.; Jayatilleke, S.K.
No abstract available