RPVJ Rajapakse

RPVJ Rajapakse


Research Focus & Metrics

Academic Career Length

35Years (1992-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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15 November 2022 in Scientific Reports
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APAmal D. Premarathna
Amal D. Premarathna
RTRando Tuvikene
Rando Tuvikene
PFP. H. P. Fernando
P. H. P. Fernando
RARanjith Adhikari
Ranjith Adhikari
MPM. C. N. Perera
M. C. N. Perera
RRRPVJ Rajapakse
RPVJ Rajapakse
Seaweed is a popular edible source and is associated with many foods and pharmaceutical industries around the world. The current research aims to provide information on the chemical composition of 15 seaweed species, consisted of Chlorophyta, Ochrophyta/Phaeophyceae, and Rhodophyta macroalgae, collected from coastal areas of Sri Lanka. Seaweed samples were subjected to the analysis of lipids, proteins, ash and macro, micro, trace and ultra-trace elements. The highest protein content was recorded in the brown algae. Maximum dietary fiber and ash contents were recorded from green algae. The highest predominant fatty acids were observed from green seaweeds (Caulerparacemosa); however, linoleic acid (C18:2n6) is the dominant fatty acid of all macroalgae. Mineral contents were highest in the red macroalga; however, copper, zinc and magnesium were also comparatively higher in green algaUlvalactuca. In conclusion, 15 seaweed species belonging to the three different classes of seaweeds are investigated in details to obtain their biochemical, mineral and fatty acid compositions for the synthesis of novel therapeutic agents. In order to explore biorefinery processes for these seaweeds, as well as how they can potentially be cultivated, more extensive studies are required. Studying and determining the nutritional values of seaweeds will be beneficial with the potentials for future industrial uses and research.

1 June 2016 in Journal of Clinical Microbiology
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YGYun Young Go
Yun Young Go
RRRPVJ Rajapakse
RPVJ Rajapakse
SKSenanayake Abeysinghe Mudiyanselage Kularatne
Senanayake Abeysinghe Mudiyanselage Kularatne
PLPei-Yu Alison Lee
Pei-Yu Alison Lee
KKKeun Bon Ku
Keun Bon Ku
UBUdeni Balasuriya
Udeni Balasuriya
Dengue virus (DENV) infection is considered a major public health problem in developing tropical countries where the virus is endemic and continues to cause major disease outbreaks every year. Here, we describe the development of a novel, inexpensive, and user-friendly diagnostic assay based on a reverse transcription-insulated isothermal PCR (RT-iiPCR) method for the detection of all four serotypes of DENV in clinical samples. The diagnostic performance of the newly established pan-DENV RT-iiPCR assay targeting a conserved 3′ untranslated region of the viral genome was evaluated. The limit of detection with a 95% confidence was estimated to be 10 copies of in vitro -transcribed (IVT) RNA. Sensitivity analysis using RNA prepared from 10-fold serial dilutions of tissue culture fluid containing DENVs suggested that the RT-iiPCR assay was comparable to the multiplex real-time quantitative RT-PCR (qRT-PCR) assay for DENV-1, -3, and -4 detection but 10-fold less sensitive for DENV-2 detection. Subsequently, plasma collected from patients suspected of dengue virus infection ( n = 220) and individuals not suspected of dengue virus infection ( n = 45) were tested by the RT-iiPCR and compared to original test results using a DENV NS1 antigen rapid test and the qRT-PCR. The diagnostic agreement of the pan-DENV RT-iiPCR, NS1 antigen rapid test, and qRT-PCR tests was 93.9%, 84.5%, and 97.4%, respectively, compared to the composite reference results. This new RT-iiPCR assay along with the portable POCKIT nucleic acid analyzer could provide a highly reliable, sensitive, and specific point-of-need diagnostic assay for the diagnosis of DENV in clinics and hospitals in developing countries.

21 February 2014 in Parasites & Vectors
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HAHarshanie Abeywardena
Harshanie Abeywardena
AJAaron R Jex
Aaron R Jex
AKAnson Koehler
Anson Koehler
RRRPVJ Rajapakse
RPVJ Rajapakse
KUKanchana Udayawarna
Kanchana Udayawarna
RGRobin Gasser
Robin Gasser
The genetic characterization of Cryptosporidium and Giardia has important implications for investigating their epidemiology and underpins their control. We undertook the first molecular epidemiological survey of domestic bovids in selected regions of Sri Lanka to establish whether they excreted Cryptosporidium and/or Giardia with zoonotic potential.

5 July 2010 in Parasites & Vectors
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LLLiang Liu
Liang Liu
MMMohammed Mh Mondal
Mohammed Mh Mondal
MIMohamed A Idris
Mohamed A Idris
HLHakim S Lokman
Hakim S Lokman
RRRPVJ Rajapakse
RPVJ Rajapakse
SAStephen Attwood
Stephen Attwood
Background: The freshwater snailIndoplanorbis exustusis found across India, Southeast Asia, central Asia (Afghanistan), Arabia and Africa.Indoplanorbisis of economic importance in that it is responsible for the transmission of several species of the genusSchistosomawhich infect cattle and cause reduced livestock productivity. The snail is also of medical importance as a source of cercarial dermatitis among rural workers, particularly in India. In spite of its long history and wide geographical range, it is thought thatIndoplanorbisincludes only a single species. The aims of the present study were to date the radiation ofIndoplanorbisacross Asia so that the factors involved in its dispersal in the region could be tested, to reveal potential historical biogeographical events shaping the phylogeny of the snail, and to look for signs thatI. exustusmight be polyphyletic.Results: The results indicated a radiation beginning in the late Miocene with a divergence of an ancestral bulinine lineage into Assam and peninsular India clades. A Southeast Asian clade diverged from the peninsular India clade late-Pliocene; this clade then radiated at a much more rapid pace to colonize all of the sampled range ofIndoplanorbisin the mid-Pleistocene.Conclusions: The phylogenetic depth of divergences between the Indian clades and Southeast Asian clades, together with habitat and parasitological differences suggest thatI. exustusmay comprise more than one species. The timescale estimated for the radiation suggests that the dispersal to Arabia and to Southeast Asia was facilitated by palaeogeographical events and climate change, and did not require human involvement. Further samples from Afghanistan, Africa and western India are required to refine the phylogeographical hypothesis and to include the African Recent dispersal.

1 August 2013 in Vector-Borne and Zoonotic Diseases
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DNDevathri M. Nanayakkara
Devathri M. Nanayakkara
RRRPVJ Rajapakse
RPVJ Rajapakse
SWSusiji Wickramasinghe
Susiji Wickramasinghe
SKSenanayaka A.M. Kularatne
Senanayaka A.M. Kularatne
Vector-borne rickettsial infection is a major cause of febrile illnesses throughout the world. Although vertebrates hosting the vectors play a vital role in the natural cycle of rickettsiae, studies have not been conducted on them in Sri Lanka. Therefore, the present study was designed to determine the exposure of dog population in Rajawatta, Thambavita, and areas of the Western Slopes and Unawatuna of Sri Lanka to rickettsial pathogens. A total of 123 dog blood samples were collected from those areas. Samples were tested for antibodies against Rickettsia conorii (RC) of the spotted fever group (SFG), Rickettsia typhi (RT) of the typhus group (TG), and Orientia tsutsugamushi (OT) of the scrub typhus group (ST) of rickettsiae by indirect immunofluorescence antibody test (IFA). Samples with titers ≥1:64 were considered as positive in this study. Collectively, 49% dogs were found to have antibodies against the rickettsial agents. Of the dogs, 42%, 24%, and 2% had antibodies against RC, OT, and RT, respectively. The seropositive rate of 100% was observed in areas of the Western Slopes, whereas the lowest rate of 20% was in Unawatuna. Among the positive samples, antibody titers against RC and OT ranged from 1/64 to 1/8192. In contrast, the few dogs that tested positive for RT showed very low titers of 1/64 and 1/128. Results of this study show the extent of exposure to the pathogen and its dispersion in the natural ecology. We suggest that dogs could be acting as reservoirs in the rickettsial transmission cycle or could be effective tracer animals that can be used to detect areas with potential for future outbreaks.

14 March 2014 in BMC Infectious Diseases
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SKSenanayake Abeysinghe Mudiyanselage Kularatne
Senanayake Abeysinghe Mudiyanselage Kularatne
IIIvb Imbulpitiya
Ivb Imbulpitiya
RARa Abeysekera
Ra Abeysekera
RWR N Waduge
R N Waduge
RRRPVJ Rajapakse
RPVJ Rajapakse
KWKosala Weerakoon
Kosala Weerakoon
Dengue infection carries a potential risk of death despite stringent management of plasma leak and haemorrhage. It appears that the extent of liver dysfunction determines the outcome.