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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Author: search.filters.author.Chandrasena, T.G.A.N.Has files: No

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    Lymphatic filariases and soil-transmitted helminthiases in Sri Lanka: the challenge of eliminating residual pockets of transmission
    (The Royal Society, 2023) Chandrasena, T.G.A.N.; Gunaratna, I.E.; Ediriweera, D.; de Silva, N.R.
    Sri Lanka has successfully met the challenge of controlling both lymphatic filariasis (LF) and soil-transmitted helminthiases (STH) as public health problems. The primary public health strategy for combatting both conditions has been preventive chemotherapy. The national programme for the elimination of LF implemented five annual rounds of mass chemotherapy in the endemic districts from 2002 to 2006 using a combination of diethylcarbamazine and albendazole. The overall microfilaria rate declined from 0.21% in 2001 before the mass chemotherapy, to 0.06% in 2016, at declaration of elimination of LF as a public health problem by the World Health Organization. Currently Sri Lanka is in the phase of post-validation surveillance. Achieving control of STH has been more difficult. Mass deworming programmes have been implemented for nearly a century, and national-level surveys reported prevalence rates declining from 6.9% in 2003 to 1% in 2017. However, neither of these infections has been completely eliminated. A situation analysis indicates continued transmission of both among high-risk communities. This paper explores the reasons for persistence of transmission of both LF and STH in residual pockets and the measures that are required to achieve long-term control, or perhaps even interrupt transmission in Sri Lanka. This article is part of the theme issue 'Challenges and opportunities in the fight against neglected tropical diseases: a decade from the London Declaration on NTDs'.
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    Annotated checklist of chigger mites (Trombidiformes: Leeuwenhoekiidae, Trombiculidae and Walchiidae) in Sri Lanka
    (Elsevier, 2022) Ashani, M.L.S.; Gunathilaka, P.A.D.H.N.; Premaratna, B.A.H.R.; Chandrasena, T.G.A.N.; Jacinavicius, F.C.; Silva, R.B.
    Chigger mites (Leeuwenhoekiidae, Trombiculidae, and Walchiidae) are parasites of any terrestrial vertebrate. The present study updates the list of chigger mite (Trombiculidae, Leeuwenhoekiidae, and Walchiidae) species recorded from Sri Lanka along with taxonomic classification based on previous investigations since 1946 to date and our observations in western and southern parts of the country. This checklist listed 15 species in 9 genera within the three chigger families. For now, murid species were the host most sampledparasitized by chiggers in Sri Lanka. However, further studies are required to increase the diversity of chigger mites in Sri Lanka and probably the description of new species, which will be possible with morphological and molecular characterization.
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    Lymphatic filariasis in the Southeast Asian region; status and control options.
    (CABI Publishing, 2020) Chandrasena, T.G.A.N.; Premaratna, R.; Mallawarachchi, C.H.; Gunaratna, D.G.A.M.; de Silva, N.R.
    ABSTRACT: The Global Program to Eliminate Lymphatic Filariasis (GPELF) was launched in year 2000 by the World Health Organization (WHO) with the goal set for elimination by 2020. Over half the global disease burden lies in the Southeast Asian region (SEAR). The preventive chemotherapy (PC) programme has been initiated in all the WHO SEAR member states with varying levels of progress. Maldives, Sri Lanka and Thailand have achieved the goal of elimination as a public health problem (EPHP) within the stipulated period with Bangladesh working towards validation in 2021. Both Sri Lanka and Thailand are continuing with post-validation surveillance combined with selective treatment, striving for zero transmission in-parallel with the morbidity management and disability prevention program (MMDP). Timor-Leste appears close to reaching critical transmission thresholds with 100% coverage and triple therapy in the last round of PC. Data on MMDP activities are insufficient to comment on reaching EPHP status. PC coverage and country reports indicate ongoing transmission in Nepal, Myanmar, Indonesia and India requiring further rounds of PC. The PELF has made considerable progress in the SEAR towards elimination but there still remain significant transmission and disease burden in the highly populated countries in SEAR.
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    Optimization of Aedes albopictus rearing procedures for combined sterile insect techniques (SIT) and Wolbachia-based laboratory studies in Sri Lanka
    (Springer Science and Business Media Deutschland GmbH, 2020) Wijegunawardana, N.D.A.D.; Gunawardene, Y.I.N.S.; Abeyewickreme, W.; Chandrasena, T.G.A.N.; Dassanayake, R.S.; Manamperi, A.
    The establishment of a laboratory colony is an essential first step for conduction of laboratory studies on the biology and control of Aedes albopictus mosquitoes. Therefore, with the objective of generating high quality mosquitoes as research material for utilization in ongoing vector control studies and to disseminate authenticated, high-quality Ae. albopictus mosquito rearing information to the research community, maintenance of an Ae. albopictus mosquito colony was initiated at the Molecular Medicine Unit, Faculty of Medicine, University of Kelaniya, Sri Lanka. A self-mating colony was established from eggs of the F1 progeny of individuals collected as free-living larvae in Narahenpita (Western Province), Sri Lanka. The mean temperature of 28 °C (± 2 °C) and relative humidity of 80% (± 5%) was constantly maintained inside the insectary. Lighting was provided by fluorescent lights, regulated with 12:12 h continuous dark and light period. Pest insects were controlled manually. Mosquitoes were maintained on bovine blood provided via an artificial membrane feeding system and a continuous supply of 10% sugar supplements. Larvae were maintained in deoxygenate water and fed with International Atomic Energy Agency (IAEA) recommended diet of tuna meal, bovine liver powder, and brewery yeast in a ratio of 37.5:27:10.5 in 1 L. Data on fecundity, fertility, larvae death, pupation, adult emergence, adult mosquito longevity were recorded. Adhering to bio-safety, all discarded materials were boiled thoroughly and incinerated if required. This report on the establishment and maintenance of a laboratory colony of Ae. albopictus will be of value for identifying the critical requirements essential under artificial conditions.
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    Human-porcine reassortant rotavirus generated by multiple reassortment events in a Sri Lankan child with diarrhea
    (Elsevier Science, 2018) Yahiro, T.; Takaki, M.; Chandrasena, T.G.A.N.; Rajindrajith, S.; Isa, H.; Ahmed, K.
    A human-porcine reassortant rotavirus, strain R1207, was identified from 74 group A rotaviruses detected in 197 (37.6%) stool samples collected from patients who attended a tertiary care hospital in Ragama, Sri Lanka. This is the first report of a human-porcine reassortant rotavirus in Sri Lanka. The patient was a 12-month-old boy who had been hospitalized with fever and acute diarrhea with a duration of 6 days. The family had pigs at home before the birth of this boy. However, the neighbors still practice pig farming. The genotype constellation of R1207 was G4-P[6]-I1-R1-C1-M1-A1-N1-T1-E1-H1. This is based on the assignment of all the eleven gene segments a full genome-based genotyping system. R1207 showed a 4-2-3-2 genomic electrophoretic migration pattern, which is characteristic of group A rotaviruses. Our analyses revealed that five (NSP2, NSP4, VP1, VP2, and VP7) of the 11 genes were closely related to the respective genes of porcine strains. Although the remaining six genes (NSP1, NSP3, NSP5, VP3, VP4, and VP6) were related to human strains, with the exception of the gene sequence of NSP1, all of these human strains were human-porcine reassortants. With a genogroup 1 genetic backbone, this strain was possibly formed via multiple genetic reassortments. We do not know whether this strain is circulating in pigs, as no data are available on porcine rotaviruses in Sri Lanka. Surveillance should be strengthened to determine the epidemiology of this genotype of rotavirus in Sri Lanka and to assess whether the infection was limited or sustained by ongoing human-to-human transmission.
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    Surveillance for transmission of lymphatic filariasis in Colombo and Gampaha districts of Sri Lanka following mass drug administration
    (Oxford University Press, 2016) Chandrasena, T.G.A.N.; Premaratna, R.; Samarasekera, D.S.; de Silva, N.R.
    BACKGROUND: Sri Lanka was recently declared by WHO to have eliminated lymphatic filariasis as a public health problem, after conclusion of annual mass drug administration. Our aim was to assess the lymphatic filariasis situation, following mass drug administration. METHODS: Surveillance was done in two districts of the Western Province in two consecutive phases (2009-2010 and 2013-2015), by examining 2461 thick night blood smears and performing 250 dipstick tests on children for antibodies to Brugia malayi. RESULTS AND CONCLUSIONS: Decline in bancroftian microfilaraemia (microfilaria rate 0.32% to zero) supports elimination, but re-emergence of brugian filariasisis (antibody rate, 1.6%; one microfilaria positive) is a cause for concern.
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    Ultrasonographic visualisation of live Wuchereria bancrofti adult worms in situ
    (Sri Lanka Medical Association, 2011) Chandrasena, T.G.A.N.; Gunawardena, N.K.; Premaratna, R.; de Silva, N.R.
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    A Survey for intestinal parasites in a psychiatric institution in Sri Lanka
    (Academic Press, 2010) Chandrasena, T.G.A.N.; Balasooriya, B.A.; Imbulpitiya, I.V.; de Silva, N.R.
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    Rotavirus infections with multiple emerging genotypes in Sri Lanka
    (Springer-Verlag, 2010) Ahmed, K.; Batuwanthudawe, R.; Chandrasena, T.G.A.N.; Mitui, M.T.; Rajindrajith, S.; Galagoda, G.; Pun, S.B.; Uchida, R.; Kunii, O.; Moji, K.; Abeysinghe, N.; Nishizono, A.; Nakagomi, O.
    Rotavirus diarrhea is an important cause of child mortality in developing countries, but studies on this diarrhea are scarce in Sri Lanka. A prospective study conducted in Sri Lanka on rotavirus infection among children in a hospital setting (n = 611) versus children residing in tsunami camps (n = 52) showed that prevalence of rotavirus infection was comparable, 21.9 and 20%, respectively. The hospital and camps were located in different districts. Analysis of the genotypes of 122 rotaviruses from the hospital and 12 from the camps indicated that G9P[8] was associated with 35 and 33%; G12P[8/nt] with 14.7 and 33%; G3P[8/4/nt] with 17 and 8% and G1P[8/4] with 6.5 and 16.7%. Rotaviruses with G2P[8/4/6] and G4P[8/4] were hospital-associated only, and some rotaviruses (9 and 8% from the hospital and the camps, respectively) were G- and P-nontypable. We conclude from the present study that multiple emerging genotypes were prevalent in Sri Lanka, and children in camps were at risk of developing diarrhea due to rotaviruses
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    Contribution of rickettsioses in Sri Lankan patients with fever who responded to empirical doxycycline treatment
    (Oxford University Press, 2010) Premaratna, R.; Rajapakse, R.P.V.J.; Chandrasena, T.G.A.N.; Nanayakkara, D.M.; Bandara, N.K.B.K.R.G.W.; Kularatne, S.A.M.; Eremeeva, M.E.; Dasch, G.A.; de Silva, H.J.
    Twenty-eight febrile Sri Lankan patients with undiagnosed fever for 7 days after hospital admission, who responded to empirical treatment with doxycycline, were retrospectively investigated using microimmunofluorescence assay to verify whether they had rickettsial infection. Eleven (39%) patients were confirmed as having spotted fever group rickettsioses and 10 (36%) as having Orientia tsutsugamushi. Seven were negative for all tests. This suggests that greater use of doxycycline appears justified for patients with undiagnosed fever in settings where rickettsial diseases are endemic or re-emerging with inadequate diagnostic facilities.