Browsing by Author "Muhandiramlage, T.P."

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Detection of Dengue Co Infections Using a Novel Single Tube Multiplex Reverse Transcription Polymerase Chain Reaction.
(In: Proceedings of the International Postgraduate Research Conference 2017 (IPRC – 2017), Faculty of Graduate Studies, University of Kelaniya, Sri Lanka., 2017) Jayathilake, E.K.S.; Jayarathne, J.A.J.C.; Muhandiramlage, T.P.; Fujii, Y.; Gunasekara, K.A.D.C.
Co-infection in individuals by more than one Dengue Virus (DENV) serotype has been reported in regions where multiple serotypes co-circulate. Co-infections can be detected using Polymerase Chain Reaction (PCR). Semi-nested multiplex PCR with Lanciotti’s primers is a widely used PCR method for serotyping DENV and it has also been used for detecting coinfections. Despite of being widely used, Lanciotti’s method may be sub-optimal in detecting co-infections as overlapping primer targets will create a bias in the amplification of the serotype with a low viral load. This could lead to underreporting of co-infections. Nine new non- overlapping primers were designed to independently amplify each serotype with minimal competition between primers to their target.In mixed infections, novel PCR assay exhibited higher sensitivity in detecting the minor serotype compared to Lanciotti’s method. The new method can also detect all four serotypes in viral RNA isolated from viral cultures and patient samples in a single tube multiplex PCR. This enables rapid and cost-effective serotyping with improved sensitivity indetection ofco-infections in clinical samples.
Larvicidal activity of the pericarp extract of Garcinia mangostana against dengue vector Aedes aegypti in Sri Lanka
(Wolters Kluwer Medknow Publications, 2022) Gunathilaka, N.; Wijebandara, Y.; Amerasinghe, D.; Udayanga, L.; Muhandiramlage, T.P.
Objective: To assess the larvicidal activity of mangosteen (Garcinia mangostana) against larval stages of Aedes aegypti mosquitoes. Methods: A crude extract was prepared in ethanol from powdered mangosteen pericarps. A concentration gradient (0.01-4.92 g/L) was prepared from the stock solution. Seven batches of 25 third instar larvae of Aedes aegypti were used for larval bioassays. Larval mortality rates were observed after one and 24 hours. Cholesterol and total lipid contents in 20 randomly selected dead larvae at each trial were assessed by colorimetric method. The experimental setup was repeated five times. The General Linear Model and Probit analysis were used to evaluate the relationship of mortality with cholesterol level, total lipid level and cholesterol to total lipid ratio. Results: The percentage mortalities significantly varied with different concentrations (F7,32=385.737; P<0.001). The LC50 and LC99 values were (0.041 ± 0.006) g/L and (10.616 ± 1.758) g/L, respectively after 24 hours. There was no mortality recorded within the one-hour exposure time. Only the cholesterol content (F5,24=173.245; P<0.001) in larvae exposed to different concentrations denoted a significantly decreasing trend within 24-hour exposure. Larvae that were exposed to the lowest concentration (0.55 g/L) showed a higher cholesterol level (22.67 ± 1.33) µg. Conclusions: The Garcinia mangostana extract acts as an effective sterol carrier protein inhibitor that inhibits cholesterol uptake in Aedes aegypti mosquitoes. Hence, it could be explored for use as a key source for the development of an environment-friendly plantbased larvicide.