Browsing by Author "Liyanage, A."

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Abundance and taxonomic characterization of chigger mites (Acari: Trombiculidae and Walchiidae) associated with rodents in selected scrub typhus-prone areas in Southern and Western provinces of Sri Lanka
(University of Kelaniya, 2024) Liyanage, A.; Gunathilaka, N.; Premarathne, R.; Chandrasena, N.; Jacinavicius, F.D.C.; Silva, R.B.
Larval trombiculid mites (chiggers) are the vectors and reservoirs of the potentially lethal infectious disease, scrub typhus (ST) caused by Orientia tsutsugamushi. Small rodents are natural hosts of parasitic larval stage of the chigger mites. This study focused on determining the abundance of chigger mites associated with rodents in Sri Lanka and the taxonomic characterization of field-caught chiggers. Field sampling was conducted in the districts of Galle, and Hambantota of the Southern Province, and Gampaha of the Western Province, in 2019 and 2020. Sampling sites were selected according to the patient distribution. Rodents were captured using baited traps (7.62 cm x 7.62 cm x 25.4 cm) set up just before sunset at peri-domestic or work premises of ST fever patients. A total of 422 traps were placed at identified possible exposure locations in Galle (n=122), Hambantota (n=120) and Gampaha (n=178). A total of 58 small mammals were captured [Galle (n=19), Hambantota (n=7), and Gampaha (n=32)] under three small rodent species, namely; Rattus rattus (Black rat), Rattus norvegicus (Brown rat), Tatera indica (Indian gerbil), Gollunda ellioti (Indian bush rat) and Suncus murinus (Asian house shrew). The trapped rodents were anaesthetized with ketamine (75 mg/kg) /xylazine (10 mg/kg) and examined for larval mites. Mites detected were removed carefully with a brush, collected, and washed individually with 10% PBS and slidemounted in Hoyer’s medium. Chiggers were speciated morphologically by visual inspection and morphometry using a camera-mounted light microscope (x100). A total of 394 life stages of mites were collected. Three different genera were identified, including Leptotrombidium, Schoengastiella, and Microtrombicula. Leptotrombidium imphalum (72.59%; n=286) was the predominant species, followed by Schoengastiella punctata (8.12%; n=32). Some specimens were identifiable only up to genus level, Leptotrombidium sp. (3.55%; n=14) and Microtrombicula sp. (4.82%; n= 19). Some (7.11%; n=28) were not trombiculid mites, while 3.81%; n=15 was damaged beyond identification. Leptotrombidium imphalum was detected for the first time parasitizing the murids - Rattus novergicus and Tatera indica in the district of Galle, a new locality. In addition, S. punctata was recorded in a new locality in the Gampaha district, Western province with a new host association, Golunda ellioti. This study emphasizes the need for further entomological surveys in ST disease-endemic areas. Developing a morphological identification key for chigger mites in Sri Lanka is a top priority to facilitate field surveys.
From reconciliation to National Development through PModel Tourist Zone in Eastern Province of Sri Lanka
(4th International Conference on Social Sciences 2018, Research Centre for Social Sciences, Faculty of Social Sciences, University of Kelaniya, Sri Lanka, 2018) Liyanage, A.; Seneratne, P.; Herath, B.
After experiencing an ethnic based civil war for 30 years and unfulfilled promises by authorities after that, Eastern province of Sri Lanka is still far behind the national development efforts. While being forced back by inadequate infrastructure facilities, lack of service industry oriented vocational training and underemployment, the province consist of enormous amount of historic and natural tourist attractions. The main problem identified for this research evolved in this back ground of having no sustainable model to reap the benefits from tourist attractions in the war affected areas in eastern province. The primary objective was to address the aforesaid issue by developing a Model Tourist Zone; a self-sufficient supply chain model with resources supplied from and within the region and minimized negative aspects related to tourism industry in Ampara district mainly Pothuvil, Lahugala and surrounding areas, which can be implemented in the other parts of the country as well. The secondary objective was finding out circumstances of tourism industry in this area. A group of 25 Tamils who were former rebel groups’ members who have entered into small scale tourism and/or politics, 15 Sinhala and/or Muslim tourism related business owners, local government members and government officials were considered for a series of focus group discussions and key informant interviews to gather information for the research. The key findings are distrust among majority of participants regarding government related development & reconciliation initiatives, inadequate infrastructure facilities, lack of tourism oriented vocational training facilities and favouritism towards corporate giants and maltreatments for small scale entrepreneurs in tourism. In conclusion, it is necessary to regain the trust of the underemployed former rebel members by skilling them on tourism and channelling their unity and strengths combined with the natural tourist attractions in the area towards national development through making them stakeholders of Model Tourist Zone.
Public knowledge, practices and perceptions on typhus fevers in Southern Sri Lanka
(Wolters Kluwer Medknow Publications, 2022) Liyanage, A.; Chandrasena, N.; Gunathilaka, N.; Sanjeewa, R.; Premaratna, R.
Objective: To assess public knowledge, practices and perceptions on typhus fevers in Sri Lanka. Methods: A descriptive study was done in four selected typhus- prone areas in Southern Sri Lanka. A mixed-method was employed using face-to-face interviews and questionnaire-based surveys among confirmed cases of typhus and at-risk populations, respectively. Frequencies, percentages, and means were used to characterize socio-demography and evaluate disease awareness. Results: The lay terms for typhus fevers reported in the studied region were “peacock fever”, “tick fever” and “bird fever”. A total of 499 subjects participated [mean±SD, (45±16) years] in the questionnaire-based survey, and 13.6% (n=68) reported past experience of typhus fever, 1.2% (n=6) identified the disease as “typhus” while 58.7% (n=293) and 11.8% (n=59) knew it as ‘peacock fever’ and ‘tick fever’, respectively. The etiological agent was unknown to 95.2% (n=475), but 53.5% ((n=267) were aware that it was vector-borne. Fever (57.3%, n=286), eschar (35.7%, n=178), headache (22.0%, n=267) and myalgia (19.2%, n=96) were identified as key symptoms. Past disease experience was significantly associated with higher awareness of the main disease symptoms (fever: χ2=15.713, P<0.001; headache: χ2=19.447, P<0.001; lymphadenopathy: Fisher’s exact test, P=0.023; eschar: χ2=12.049, P<0.001). None knew of any disease prevention methods. Participants with a past history of typhus fever had sought treatment at state hospitals (55.9%, 38/68) and private sector hospitals (5.9%, 4/68). Conclusions: Public awareness on preventive practices for typhus fevers was rare among the participants though vector-borne aspect was known to many. Clinical disease awareness was deficient among those without past experience of typhus fever. Community sensitization on vector avoidance strategies is highly recommended.
Treatment failure to sodium stibogluconate in cutaneous leishmaniasis: A challenge to infection control and disease elimination
(PLoS ONE, 2021) Silva, H.; Liyanage, A.; Deerasinghe, T.; Chandrasekara, V.; Chellappan, K.; Karunaweera, N. D.
The first-line treatment for Leishmania donovani-induced cutaneous leishmaniasis (CL) in Sri Lanka is intra-lesional sodium stibogluconate (IL-SSG). Antimony failures in leishmaniasis is a challenge both at regional and global level, threatening the ongoing disease control efforts. There is a dearth of information on treatment failures to routine therapy in Sri Lanka, which hinders policy changes in therapeutics. Laboratory-confirmed CL patients (n = 201) who attended the District General Hospital Hambantota and Base Hospital Tangalle in southern Sri Lanka between 2016 and 2018 were included in a descriptive cohort study and followed up for three months to assess the treatment response of their lesions to IL-SSG. Treatment failure (TF) of total study population was 75.1% and the majority of them were >20 years (127/151,84%). Highest TF was seen in lesions on the trunk (16/18, 89%) while those on head and neck showed the least (31/44, 70%). Nodules were least responsive to therapy (27/31, 87.1%) unlike papules (28/44, 63.6%). Susceptibility to antimony therapy seemed age-dependant with treatment failure associated with factors such as time elapsed since onset to seeking treatment, number and site of the lesions. This is the first detailed study on characteristics of CL treatment failures in Sri Lanka. The findings highlight the need for in depth investigations on pathogenesis of TF and importance of reviewing existing treatment protocols to introduce more effective strategies. Such interventions would enable containment of the rapid spread of L.donovani infections in Sri Lanka that threatens the ongoing regional elimination drive.