Browsing by Author "Rodrigo, W. W. P."

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    Duplex polymerase chain reaction (Duplex-PCR) to identify adulterations in chicken and turkey meat products
    (4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Chamindi, K. A. W.; Rodrigo, W. W. P.; Jayawardhana, B. J. G.
    Adulteration is a process, which decreases the quality of food by the addition of low quality materials and removal of valuable ingredients. Nowadays, meat adulteration is a major concern worldwide, because of the falsely labeled food products. Consumers demand accurate labeling of these meat products to avoid economic, religious and health issues. Therefore, the aim of this study was to validate a molecular based assay i.e Duplex polymerase chain reaction (Duplex-PCR), to identify adulterations in chicken and turkey meat products to provide the correct details to consumers. Samples were collected from local supermarkets. DNA was extracted from raw, cooked and processed chicken and turkey food samples using the Qiagen Mericon® food kit and this was followed by a spot gel test to confirm the presence of DNA. The cooked samples were pre-treated before the DNA extraction. Duplex-PCR based molecular identification method using species-specific primers based on mitochondrial cytochrome b gene was performed. The PCR resulted 190 bp and 150 bp fragments for chicken and turkey DNA respectively. Repeatability, recovery and reproducibility were checked to validate the method. The repeatability of the overall samples was more than 80% where one of the validation parameter was successfully achieved and the recovery (sensitivity) was detected as 3 mg (1.5%). The results of reproducibility indicated same results for three analysts, which confirmed the procedure was not depend on personal errors. Since the necessary parameters for validation are effectively achieved, the duplex-PCR based method for molecular identification of chicken and turkey can be validated. This method was used to detect adulterations of ten processed/pre-cooked chicken and turkey products. Results showed that, roasted turkey and turkey sausage, which had been declared as turkey was adulterated with chicken. Chicken ham and two brands of chicken sausages that had been declared as chicken, was adulterated with an unknown species. Since the adulteration was detected in meat products effectively, the duplex-PCR method for detection of meat adulteration of turkey and chicken is successful
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    Presence of leishmaniasis causing agent, Leishmania donovani, in biting midges (Culicoides sp) at a disease endemic area of Sri Lanka: Could it be a probable vector?
    (Faculty of Graduate Studies, University of Kelaniya Sri Lanka, 2022) Wijerathna, T.; Wimalasiri, U.; Wijegunawardena, A.; Gunathilaka, N.; Rodrigo, W. W. P.
    Biting midges are a group of dipteran insects of the family Ceratopogonidae. Some species of biting midges are known to be vectors for filaria parasites that infect humans, and some are known to be vectors of viruses that infect livestock. Evidence suggests that biting midges may be a potential vector for Leishmania parasites in other countries. Biting midges are found in high densities in leishmaniasis endemic regions of Sri Lanka. This high density and biting nuisance suggest that these insects may have a possible role as secondary vectors (if not primary vectors) for leishmaniasis in these areas. The first criterion of leishmaniasis vector incrimination is the detection of parasites from the suspected vectors. Therefore, the present study examined the Leishmania donovani parasites circulate within biting midge populations at a leishmaniasis endemic area in Sri Lanka. The study was conducted in Medawachchiya Medical Officer of Health area in Anuradhapura District, Sri Lanka. Biting midges were collected using cattle baited net traps during December 2021. The collected specimens were identified using morphological identification keys. The specimens were surface sterilized using 70% ethanol and the DNA was extracted from the fly using MightyPrep reagent for DNA (Takara, Japan). The parasite DNA was detected using a Polymerase Chain Reaction (PCR) using Leishmania donovani specific primers that target kinetoplast minicircle gene. The amplicons were visualized under UV light after running on a 2% agarose gel stained with ethidium bromide. A total of 42 biting midges were collected and all of them were females. The collection consisted of a single species similar to Culicoides imicola in morphology. The gel electrophoresis and subsequent UV visualization indicated that two of the samples were positive for L. donovani DNA indicating a parasite circulation rate of 4.76% within the wild biting midge population. The results of the current study suggest that the L. donovani, the main causative agent of leishmaniasis in Sri Lanka, circulates within biting midge populations indicating a possibility of this species being a vector for leishmaniasis in Sri Lanka. According to the World Health Organization (WHO) criteria for leishmaniasis vector incrimination, the detection of the parasites within the insect is the first step. Further studies to assess the luxuriant growth of the parasite within midge midgut and experimental transmission using animal models are needed to confirm the vector status. Considering the medical and veterinary importance, the studies on biting midges of Sri Lanka are recommended.