Conference Papers

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This collection contains abstracts of conference papers, presented at local and international conferences by the staff of the Faculty of Medicine

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Author: search.filters.author.Chandrasena, T.G.A.N.Has files: Yes

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Now showing 1 - 10 of 19
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    A preliminary survey for filarial parasites among dogs and cats in mahawewa, puttalam and their vector identification
    (Elsevier, 2022) Nimalrathna, S.; Mallwarachchi, C.; Chandrasena, T.G.A.N.; de Silva, N.; Kimber, M.; de Silva, N.R.; Harischandra, H.
    PURPOSE This study investigated the prevalence of zoonotic filarial parasites within the canine and feline population in Mahawewa, Puttalam, and their vectors based on a brugian filariasis positive human case reported to the Anti-filariasis Campaign in January 2021.METHODS & MATERIALS All reachable dogs and cats, both stray and domestic, within a 500m radius of the index human case of brugian filariasis were screened for microfilaria using Giemsa stained thick blood smears prepared from capillary blood, obtained from an ear-lobe prick. Mosquito collection was done using a dog-baited trap, two window traps and a B.G. Sentinel trap from the same study site and identified using morphological keys. The head and the thorax regions of randomly selected mosquito specimens were dissected for morphological identification of larval filaria parasites via microscopy. RESULTS A total of nine dogs and three cats were surveyed, of which seven dogs and one cat had filarial infections. All the infected animals harbored B.malayi microfilariae, while four dogs and one cat were co-infected with Dirofilaria repens and two dogs with an unidentified species. A total of 119 mosquitoes were caught and identified by taxonomic keys using a dog-baited trap, two window traps and a B.G. Sentinel trap from the study site. Dissection of heads and thoraces of randomly selected 12 Mansonia annulifera, 18 Mansonia indiana 20 Mansonia uniformis and 8 Culex spp. revealed filarial larvae in M.annulifera (n=4, 33.33%), M. indiana (n=14, 77.78%), M. uniformis (n=10, 50.00%) and Culex spp.(n=5, 62.5%) via microscopy. CONCLUSION M.indiana was incriminated as a potential vector of filarial parasites for the first time in Sri Lanka. Preliminary evidence generated indicate a high prevalence of B.malayi and D.repens among dogs and cats in Mahawewa, Puttalam with an abundance of mosquito vectors mostly of Mansonia and Culex spp. This warrants further studies with a larger sample size and molecular identification of the filarial larvae within mosquito and animal samples, especially as re-emergence of brugian filariasis in humans is being reported after four decades of quiescence, and a zoonotic brugian parasite has been detected over the recent past, raising a concern from a one health perspective.
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    Occurence of tick bits and serological evidence of exposure to rickettsioses among Sri Lankan military personnel
    (International Society for Infectious Diseases, 2009) Premaratna, R.; Chandrasena, T.G.A.N.; Nawasiwatte, B.M.T.P.; Kulasiry, K.I.R.; Rajeev, S.; Bandara, K.B.K.R.G.W.; Rajapakse, R.P.V.J.; Kularatna, S.A.M.; de Silva, H.J.
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    Predicted cost benifits of establishment of Ricckettsial didease diagnostics in Sri Lanka
    (American Society of Rickettsiology, 2008) Premaratna, R.; Dissanayake, I.; Chandrasena, T.G.A.N.; Attanayake, N.; de Silva, H.J.
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    Rickettsial infections and their clinical presentations in the Western Province of Sri Lanka: A hospital based study
    (American Society of Rickettsiology, 2007) Premaratna, R.; Loftis, A.D.; Chandrasena, T.G.A.N.; Dasch, G.A.; de Silva, H.J.
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    The role of antioxidants in filarial infection
    (Royal Society of tropical medicine and Higiene (RSTMH), American Society of tropical medicine and Higiene(ASTMH), British Society for Parasitology, 2000) Premaratna, R.; Chandrasena, T.G.A.N.; Senarath, S.; Chandrasena, L.G.; de Silva, N.R.; de Silva, H.J.
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    Etiology of fever of unknown origin in a selected group of Sri Lankan patients with prompt responses to Doxycycline
    (Centers for disease control and Prevention, 2008) Dasch, G.A.; Premaratna, R.; Rajapakse, R.P.; Chandrasena, T.G.A.N.; Eremeeva, M.E.; de Silva, H.J.
    BACKGROUND: Most patients with long duration of fever go undiagnosed in settings where diagnostic facilities are inadequate. Untreated rickettsial infections cause extended fevers; while both scrub typhus and tick typhus are re-emerging diseases in Sri Lanka, laboratory facilities to specifically diagnose rickettsial infections in Sri Lanka are not available. METHODS: We collected 2 ml venous blood from febrile patients who had no etiological diagnosis after 7 days of hospital admission, but who showed rapid clinical response to doxycycline, to verify whether they had experienced a rickettsial infection. Acute serum samples were analysed using IFA for rickettsial infections caused by Orientia tsutsugamushi, Rickettsia conorii and Rickettsia typhi. A positive IgG IFA titer >1:128 was used to define a probable case of rickettsial infection. RESULTS: 28 patients [15 males, mean age 32.5 (SD 9.2 yrs)] were studied. Mean duration of fever at admission was 6.1 days (SD 3.1). Two patients had features suggestive of encephalitis and two had erythema nodosum. Others had no specific clinical features. Routine investigations were inconclusive and blood cultures were negative. IgG-IFA titer of >128 was found in 10 for R. conorii, 6 for O. tsutsugamushi and 6 for both R. conorii and O. tsutsugamushi. None were positive for R. typhi. Six were negative for all tests. One patient with encephalitis and one with erythema nodosum had high titers for R. conorii. CONCLUSIONS: The majority of Sri Lankan patients with undiagnosed fever responding promptly to doxycycline had a rickettsial etiology. Patients with rickettsioses exhibit varied clinical presentations so greater use of doxycycline for patients with extended fevers in rickettsial-endemic settings with inadequate diagnostic facilities appears warranted. The high proportion of patients with tick typhus and antibodies against both spotted fever and scrub typhus rickettsiae was unexpected based on previous studies of patients from the same region who were confirmed to have scrub typhus by serology and by the presence of the classic eschar. It is unknown whether the etiology of tick typhus and vector(s) transmitting this agent on the Western lowland region of Sri Lanka are the same as those responsible for spotted fevers in the central hill country of Sri Lanka.
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    Clearance of microfilaraemia and red blood cell glutathione peroxidase(GPX) levels in asymptomatic microfilaraemics after single dose and 14 days’ treatment with diethyl carbamazine citrate(DEC) 
    (Sri Lanka Medical Association, 2001) Premaratna, R.; Chandrasena, T.G.A.N.; Abeyewickreme, W.; de Silva, N.R.; Chandrasena, L.G.; de Silva, H.J.
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    Clearance of microfilaraemia and red blood cell glutathione peroxidase(GPX) levels in asymptomatic microfilaraemics after single dose and 14 days’ treatment with diethyl carbamazine citrate(DEC)
    (Wiley, 2001) Premaratna, R.; Chandrasena, T.G.A.N.; Abeyewickreme, W.; de Silva, N.R.; Chandrasena, L.G.; de Silva, H.J.
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    Red blood cell antioxidant levels after treatment with diethyl carbamazine
    (Wiley, 2001) Premaratna, R.; Chandrasena, T.G.A.N.; Abeyewickreme, W.; de Silva, N.R.; Chandrasena, L.G.; de Silva, H.J.
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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.