Browsing by Author "Bandara, N.B."

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    Prevalence of rickettsial infections in acute coronary syndromes in Sri Lanka: A case control study
    (Elsevier, 2016) Mettananda, K.C.D.; Premaratna, R.; Danansuriya, D.; Bandara, N.B.
    BACKGROUND: Interest in the relationship between infection and atherosclerosis induced coronary heart disease has recently increased. Rickettsiae are a group of obligate intracellular pathogens who invade endothelial cells and cause vasculopathy. In a longitudinal nation wide study conducted in Thaiwan, the incidence of acute coronary syndromes (ACS) in patients with scrub typhus was found to be higher than a comparison cohort (3.10 vs 1.92 per 1000 person-years). A 37% increased risk in subsequesnt development of ACS has been demonstrated compared to general population after adjusting for age, sex and other indipendant risk factors; hypertension, diabetes, hyperlipidaemia, chronic obstructive pulmonary disease and coronary artery disease. The prominent effect of scrub typhus on subsequent ACS development has appeared within 1 year after infection. AIMS: To assess the prevalence of Rickettsial infections in patients with ACS who live in the Western province, Sri Lanka. METHODS & MATERIALS: Patients admitted with ACS to the Professorial Medical Unit, Colombo North Hospital, Ragama, Sri Lanka from April to December 2011 were studied for the serological prevalence of rickettsial infections and were compared with a matched control group; who had no fever or ACS and admitted during the same period. 2 ml serum samples were obtained at enrolment and 2 weeks after, to assess exposure to rickettseal infections by IFA-IgG antibody titres against Orientia Tsutsugamushi (OT) and Spotted fever group (SFG) rickettsioses. An IgG titre ›1:128 or a rising/declining titre were considered positive for acute rickettsioses. A static titre was considered previous exposure to Rickettsioses. RESULTS: 46 ACS [males n(23.9%), mean age (SD) 61.1(13.1) y] and 52 controls (males n (50%), mean age(SD) 56.0(13.6) y] were studied. None had evidence of acute rickettsiel infection. Sero-prevalence of IgG (OT) was 6.4% and IgG-SFG was 15.2% among ACS patients while that of control group were 3.8% and 11.5% respectively. There was no significant difference in sero-prevalence of OT [OR =0.74 (CI, 0.28-10.93), p=0.66] or SFG [OR=1.376 (CI, 0.43-4.44), p=0.59] in patients with ACS compared to controls. CONCLUSION: We observed no significant difference in sero-prevalence of rickettsioses in patients with acute coronary syndromes compared to controls in this study.
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    Rickettsial disease IFA-IgG titres in auto-immune diseases: What do they imply?
    (Elsevier, 2016) Balasooriya, P.; Bandara, N.B.; Chandrasena, T.G.A.N.; Premaratna, R.
    BACKGROUND: Rickettsial infections are known to present mimicking autoimmune disorders. The gold standard diagnostic test for rickettsial diseases is based on the detection of IgM and or IgG antibodies against these infections by immuno-fluorescent technique (IFA). While confirmation of rickettsial diseases warrant demonstration of rising or declining antibody titres between acute and convalescent samples, high titres of either IFA-IgM or IFA-IgG in acute phase serum in patients with a compatible clinical illness may help in the presumptive diagnosis and introduction of anti-rickettsial antibiotics. During the IFA test, patient sera containing anti rickettsial antibodies are made to react with rickettsial antigens that are grown in cell culture media. However, presence of nuclear material in these cell cultures may react with anti-nuclear antibodies that are produced in autoimmune disorders and cause a false positive immunofluorescent signal. METHODS & MATERIALS: In order to evaluate the reactivity of rickettsial disease IFA-IgG test [IFA-IgG-OT (Orientia tsutsugamushi) and IFA-IgG-SFG (spotted fever group)] among patients with autoimmune diseases, an analytical cross-sectional study was carried out using sera of 38 patients with confirmed auto-immune diseases. RESULTS: The 38 patients included 15 systemic lupus erythematosus (SLE), 5 autoimmune-thyroiditis, 13 idiopathic-thrombocytopenia (ITP), 4 autoimmune-haemolytic-anaemia (AIHA), 1 polymyositis, 1 polyglandular syndrome and 1 Anti-phospholipid syndrome. The IFA-IgG reactivity of ≥ 1:128 was noted in 14/38 (37%); IFA-IgG-SFG in 7, IFA-IgG-OT in 3 and for both in 4. Of the 14; titre of 1:128 in 2, 1:256 in 4, 1:512 in 5, >1: 1024 in 3 and 8/14 (57%) were SLE, 3/14 (21.4%%) were ITP, 2/14 (14.3%) were AIHA, 1/14 (7.1%) were polymyositis and none were thyroiditis. 8/14 had received anti-rickettsial antibiotics during the early stages of illness based on the clinical presentation and high IFA-IgG titres. CONCLUSION: There was a significant reactivity of Rickettsial disease IFA-IgG assay in auto-immune diseases. Further studies are needed in order to ascertain whether this is due to recent rickettsial infections, false positive cross reactivity of autoimmune antibodies with rickettsial antigens or with cell culture nuclear antigens. We did not carry out IFA-IgM due to non-availability and non-affordability.