Medicine
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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty
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Item Rickettsial illnesses, a leading cause of acute febrile illness(The Royal College of Physicians of London, 2022) Premaratna, R.Rickettsial illnesses, comprising mainly spotted fever group, typhus group and scrub typhus, are vector-borne re-emerging or newly emerging febrile illnesses where humans are an accidental dead-end host. They are a major cause of non-malarial febrile illnesses among returned travellers. They commonly present as an acute febrile illness and carry a characteristic entry wound (eschar) or a discrete erythematous maculo-popular rash based on the organism and the region. The illness severity is mainly dependent on the virulence of the rickettsial organism and delay in the diagnosis is known to cause severe illness with multi-organ involvement carrying high mortality. Almost all rickettsial infections respond to anti-rickettsial antibiotics such as doxycycline within 48-72 hours. Awareness of rickettsial illnesses and their various clinical presentations helps in early diagnosis and institution of appropriate treatment and hence prevent morbidity and mortality.Item Genotypic characterization of Orientia tsutsugamushi from patients in two geographical locations in Sri Lanka(BioMed Central, 2017) Premaratna, R.; Blanton, L.S.; Samaraweera, D.N.; de Silva, G.N.N.; Chandrasena, T.G.A.N.; Walker, D.H.; de Silva, H.J.BACKGROUND: To date more than 20 antigenically distinct strains of Orientia tsutsugamushi (OT) reported within the tsutsugamushi triangle that cause an undifferentiated acute febrile illness in humans. Genotypic characterization of OT in different geographic regions or within the same country, is important in order to establish effective diagnostics, clinical management and to develop effective vaccines. Genetic and antigenic characterization of OT causing human disease in OT-endemic regions is not known for Sri Lanka. METHODS: Adult patients and children who were admitted with an acute febrile illness and presumed to having acute scrub typhus based on presence of an eschar and other supporting clinical features were recruited. Eschar biopsies and buffy coat samples collected from patients who were confirmed having OT by IFA were further studied by real time PCR (Orientia 47 kD) and nested PCR (Orientia 56 kD) amplification. DNA sequences were obtained for 56 kD gene amplicons and phylogenetic comparisons were analyzed using currently available data in GenBank [Neucleotide substitution per 100 residues, 1000 Bootstrap Trials]. RESULTS: Twenty eschar biopsies (Location1,19, Location 2,1) and eight buffy coat samples (Location1,6, Location2,2) examined by real time PCR revealed Orientia amplicons in 16 samples. DNA sequences were obtained for the 56 kD gene amplicons in 12 eschars and 4 buffy coat samples. The genotypes of the Location1 samples revealed that, 7 exhibiting close homology with JP1 [distantly related to UT177 Thai (Karp related)], five had close homology with Kato strain, two had close homology with JGv and JG AF [Distantly related to Kawasaki M63383] and one had close homology with Gilliam strain. The Location 2 strain was closely related to Kuroki-Boryong L04956, the genotype which is distributed in far eastern Asia. Similar to other patients in the cohort this patient also had never travelled out of Sri Lanka. CONCLUSIONS: We observed all three main OT genotypes in Sri Lanka, and the majority fell into Thai Karp related clade. These results demonstrate great antigenic diversity of OT in the studied areas of Sri Lanka.Item Acute hearing loss due to scrub typhus: a forgotten complication of a reemerging disease(Oxford University Press, 2006) Premaratna, R.; Chandrasena, T.G.A.N.; Dassanayake, A.S.; Loftis, A.D.; Dasch, G.A.; de Silva, H.J.We describe 6 patients with scrub typhus who presented with acute hearing loss, a forgotten complication of this reemerging disease. They were admitted with fever of 10-14 days' duration and had clinical evidence of deafness and pneumonitis. Five patients had eschars, which prompted the diagnosis of typhus fever and led to early institution of treatment. Deafness has been described as a clue to the diagnosis of scrub typhus; awareness of this symptom facilitated early diagnosis in 4 of 5 patients who recovered. Acute hearing loss or hearing impairment in a febrile patient should arouse strong suspicion of scrub typhus.