Browsing by Author "Fernando, T."

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Anopheles culicifacies breeding in polluted water bodies in Trincomalee district of Sri Lanka
(BioMed Central, 2013) Gunathilaka, N.; Fernando, T.; Hapugoda, M.; Wickremasinghe, R.; Wijeyerathne, P.; Abeyewickreme, W.
BACKGROUND: Anopheles culicifacies, the major vector of malaria in Sri Lanka, is known to breed in clean and clear water. The main objective of the study was to detect the breeding habitat diversity of An. culicifacies. METHODS:Potential larval habitats for Anopheles mosquitoes were surveyed on a monthly basis for 17 months (January 2011--June 2012) in four different selected sampling sites (Murthankulam, Kommnaimottai, Paranamadawachchiya and Kokmotawewa) in Trincomalee District of Sri Lanka. RESULTS: A total of 2,996 larval specimens representing 13 Anopheles species were reported from 16 different breeding habitats. According to density criterion, An. culicifacies, Anopheles subpictus, Anopheles barbirostris, Anopheles peditaeniatus and Anopheles nigerrimus were dominant. Anopheles nigerrimus, An. subpictus and An. peditaeniatus were observed as constant in relation to their distribution. The most productive breeding site for An. culicifacies was drains filled with waste water in remote areas; the second highest productivity was found in built wells. CONCLUSIONS: These results indicate that An. culicifacies has adapted to breed in a wide range of water bodies including waste water collections although they were earlier considered to breed only in clean and clear water. Copyright © 2013 Gunathilaka et al.; licensee BioMed Central Ltd.
Biocontrol potential of six locally available fish species as predators of Aedes aegypti in Sri Lanka
(Elsevier Ltd, 2021) Ranathunge, T.; Kusumawathie, P.H.D.; Abeyewickreme, W.; Udayanga, L.; Fernando, T.; Hapugoda, M.
ABSTRACT: This study was conducted to evaluate the potential of six locally abundant fish species to control Aedes mosquito larvae and thereby manage dengue epidemics in a sustainable, cost-effective and environmentally friendly manner. The biocontrol efficacy of six larvivorous fish species, namely, Poecilia reticulata, Rasbora daniconius, Aplocheilus dayi, Oriochromis mossambicus, O. niloticus and Puntius bimaculatus, was evaluated under laboratory and field conditions. Five size-matched fish (of the same species) were introduced into separate tanks (replicates) containing 2 L of dechlorinated water and 200 third instar larvae of Aedes aegypti (L.). The number of larvae consumed by each fish species was recorded at three-hour intervals for 24 h. Acclimatized fish were introduced into a total of eighteen artificial breeding habitats located in the Gampola Medical Officer of Health (MOH) area at the species level with three replications. In addition, three breeding sites without fish were monitored as controls. Aedes larvae were monitored by dipping and siphoning methods in each breeding habitat at weekly intervals for three months and the number of fish surviving in each habitat was tallied. Over 24 h under laboratory conditions, O. mossambicus showed the highest predation rate, consuming 320.2 ± 14.5 larvae per day, with a predatory efficiency of 87.5 ± 3.5%. In comparison, O. niloticus consumed 264.6 ± 12.2 larvae per day with consumption efficiciency of 78.1 ± 3.7%, whereas R. daniconius had the lowest larval consumption (33.2 ± 2.7 larvae per day) and predatory efficiency (33.2 ± 3.2%). Over 12 weeks of observation under field conditions, breeding sites with Ap. dayi had the lowest Aedes larval counts, followed by Po. reticulata. Considering predation efficiency and survival under field conditions, Ap. dayi and Po. reticulata were considered to be the best potential candidates for biological control of Ae. aegypti. Further studies under field settings are warranted to evaluate the survival and predatory potential of the selected candidates under more varied environmental conditions.
Dietary goitrogens and prevalence of goitre in Sri Lanka
(The College of Surgeons of Sri Lanka, 2011) Pinto, M. D. P.; Fernando, R.; Pathmeswaran, A.; Premathilake, M.; Fernando, T.; Edirisinghe, D.; Bandara, D.; Athulugama, N.; Abeysinghe, S.
OBJECTIVE: To assess the relationship between dietary goitrogens and the prevalence of goiter. METHODS:A descriptive cross-sectional study on the prevalence of goitre was conducted involving all areas of the country, except North and Batticaloa district from December 2006 to June 2007. A pre-tested interviewer administered questionnaire was used on all participants as a screening tool. Consumption of 6 possible dietary goitrogens was assessed. Sufficient frequency of consumption was taken as consumption >3 times a week. Pearson's chi-square test was used to analyze the significance of dietary goitrogens to the prevalence of goiter. RESULTS: 5200 participants were assessed (n=5200) island wide and 426 were detected with goitre. Mean age for occurrence of goitre was 36.3(+_17.3) years. Frequency of consumption of these food items was low, none being higher than 10% among the 5200 participants. Consumption of each goitrogen was as follows; Cabbage "[2.9%], Lima beans [9.9%], Kurakkan (Millet) [4%], Turnip [2.9%], Manioc(Cassava) [2.2%] and Peanuts [5.5%]. All six dietary goitrogens showed no significant association with the occurrence of goitre (p<0 05).CONCLUSION:Dietary goitrogens do not appear to have an association with prevalence of goitre in this cohort. As this cohort is a representative sample, dietary goitrogens are unlikely to be associated with prevalence of goitre in Sri Lanka.
High levels of serum angiopoietin 2 and angiopoietin 2/1 ratio at the critical stage of Dengue Hemorrhagic Fever in patients and association with clinical and biochemical parameters
(American Society for Microbiology., 2020) Mapalagamage, M.; Handunnetti, S.M.; Wickremasinghe, A.R.; Premawansa, G.; Thillainathan, S.; Fernando, T.; Kanapathippillai, K.; de Silva, A.D.; Premawansa, S.
ABSTRACT:Longitudinal changes of serum angiopoietin 1 (Ang-1) and angiopoietin 2 (Ang-2) associated with endothelial stability in dengue patients with different disease stages were studied. Serum Ang-1 and Ang-2 levels were measured in confirmed dengue fever (DF) patients on admission (DFA, n = 40) and discharge (DFD, n = 20); in dengue hemorrhagic fever (DHF) patients on admission (DHFA, n = 40), at critical stage (DHFC, n = 36), and on discharge (DHFD, n = 20); and in healthy controls (HC, n = 25). DHFC had the highest serum Ang-2 and lowest Ang-1 levels compared to DFA, DHFA, and HC (P < 0.050). The ratio of serum Ang-2/Ang-1 in DHFC was the highest among all study categories tested (P < 0.001). Significant positive correlations were observed between serum Ang-1 and platelet count in DHFA (Pearson r = 0.653, P < 0.001) and between Ang-1 and pulse pressure in DHFC (r = 0.636, P = 0.001). Using a cutoff value of 1.01 for the Ang-2/Ang-1 ratio for DHFC, a sensitivity of 83.2% and a specificity of 81.2% discerning DF from DHF were obtained. Therefore, serum Ang-2/Ang-1 could be used as a biomarker for endothelial dysfunction in severe dengue at the critical stage. KEYWORDS: angiopoietin; biomarker; dengue fever; dengue hemorrhagic fever; endothelial dysfunction.
Is Total Serum Nitrite and Nitrate (NOx) Level in Dengue Patients a Potential Prognostic Marker of Dengue Hemorrhagic Fever?
(Hindawi Pub. Corp., 2018) Mapalagamage, M.; Handunnetti, S.; Premawansa, G.; Thillainathan, S.; Fernando, T.; Kanapathippillai, K.; Wickremasinghe, R.; de Silva, A.D.; Premawansa, S.
Potential use of total nitrite plus nitrate (NOx) and nitrite (NO2-) separately as surrogate markers for serum nitric oxide in severe dengue and their longitudinal changes along with the progression of infection was studied. Deproteinized sera from confirmed dengue fever (DF, n = 145) and dengue hemorrhagic fever (DHF, n = 74) patients on admission-A, critical-C, discharge-D, and convalescence-CON stages and from age-gender matched healthy individuals (HC, n = 77) were taken to assess NO2- and NOx levels using Griess and modified Griess assays. Serum NOx in DHFA was significantly lower compared to DFA (p < 0.001). HC had the lowest NOx and NO2- compared to all patient categories (p < 0.001) except NO2- in DF-CON and DHF-CON and NOx in DHF-CON. Serum NOx and NO2- in DHF patients admitted on fever day 3 (DHFA-3) was significantly lower compared to DFA-3 (p < 0.05). Cut-off values of 4.46 μM for NOx (91.3% sensitivity and 80.1% specificity) and 1.25 μM for NO2-(75.0% sensitivity and 73.3% specificity) were obtained for day 3 of fever. Serum NOx may be used as potential prognostic marker of DHF in patients presenting with DF in the early stage (on day 3 of fever) of the disease.
Larval indices of vector mosquitoes as predictors of dengue epidemics: An approach to manage dengue outbreaks based on entomological parameters in the districts of Colombo and Kandy, Sri Lanka
(Hindawi Pub. Co., 2020) Udayanga, L.; Aryaprema, S.; Gunathilaka, N.; Iqbal, M. C. M.; Fernando, T.; Abeyewickreme, W.
BACKGROUND: Early detection of dengue epidemics is a vital aspect in control programmes. Predictions based on larval indices of disease vectors are widely used in dengue control, with defined threshold values. However, there is no set threshold in Sri Lanka at the national or regional levels for Aedes larval indices. Therefore, the current study aimed at developing threshold values for vector indices in two dengue high-risk districts in Sri Lanka. METHODS: Monthly vector indices (House Index [HI], Container Index [CI], Breteau Index for Aedes aegypti [BIagp], and Ae. albopictus [BIalb]), of ten selected dengue high-risk Medical Officer of Health (MOH) areas located in Colombo and Kandy districts, were collected from January 2010 to June 2019, along with monthly reported dengue cases. Receiver Operating Characteristic (ROC) curve analysis in SPSS (version 23) was used to assess the discriminative power of the larval indices in identifying dengue epidemics and to develop thresholds for the dengue epidemic management. RESULTS: Only HI and BIagp denoted significant associations with dengue epidemics at lag periods of one and two months. Based on Ae. aegypti, average threshold values were defined for Colombo as Low Risk (2.4 ≤ BIagp < 3.8), Moderate Risk (3.8 ≤ BIagp < 5), High Risk (BIagp ≥ 5), along with BIagp 2.9 ≤ BIagp < 4.2 (Low Risk), 4.2 ≤ BIagp < 5.3 (Moderate Risk), and BIagp ≥ 5.3 (High Risk) for Kandy. Further, 5.5 ≤ HI < 8.9, 8.9 ≤ HI < 11.9, and HI ≥ 11.9 were defined as Low Risk, Moderate Risk, and High Risk average thresholds for HI in Colombo, while 6.9 ≤ HI < 9.1 (Low Risk), 8.9 ≥ HI < 11.8 (Moderate Risk), and HI ≥ 11.8 (High Risk) were defined for Kandy. CONCLUSIONS: The defined threshold values for Ae. aegypti and HI could be recommended as indicators for early detection of dengue epidemics and to drive vector management activities, with the objective of managing dengue epidemics with optimal usage of financial, technical, and human resources in Sri Lanka.
Preserve Asian folk archives
(University of Kelaniya, 2011) Manatunga, Anura; Jayasekara, A.H.D.; Fernando, T.; Upadhyay, V.
“Preserve Asian Folk Archives”, is one of the attempts to preserve and undertake research on folk documents which were hitherto considered as less important and often perished unnoticed. The problem of this research is there is no place to conserve folk documents considered as less important. Our understanding is that these materials are an essential part of our heritage and a representation of the culture and society in which they were produced and circulated. As source material of social history these folk documents would be more important and interesting than „recognized documents‟ housed in conventional archives. We have begun to use cyber space for preserving folk documents, which are endangered. It is indeed impractical to think of preserving all sorts of folk documents circulating in society. Moreover, it is not necessary to preserve everything belonging to the past or present for the sake of the future. Therefore, our intention is to preserve only a meaningful sample of folk documents in the Asian Folk Archives. Document categories for the purposes of this archive is an aspect of this study. Some of the categories are: old photographs, drawings and pictures, old diaries and private letters, notebooks, lecture notes, essays and reports, child art, folk art and calligraphy. The language of the document, place of its origin or content of the document shall not be a concern for us, if they are, morally, ethically and legally suitable for display in our research. This research is being set up in cyber space initially, and will be developed into full fledged archives or several archives in due course. In addition to separate „Public Archives‟, we encourage „in-house Archives‟ in residential and office spaces for folk archival materials. Moreover, we would like to join hands with archives‟ authorities to improve already existing folk collections in their archives and urge them to motivate archiving. This is on-going research and we wish to preserve folk documents for future generations.
Revised morphological identification key to the larval anopheline (Diptera: Culicidae) of Sri Lanka
(Asian Pacific Tropical Medicine Press, China, 2014) Gunathilaka, N.; Fernando, T.; Hapugoda, M.; Abeyewickreme, W.; Wickremasinghe, R.
OBJECTIVE: To revise morphological identification keys to the anophelines in Sri Lanka. METHOD: Samples were collected from selected entomological sites in different districts in the country. Stage III and IV larvae were identified under a light microscope with an objective (×10) using standard larval keys developed for Sri Lankan anophelines. Key larval characters were recorded for each species based on original observations and previous usage in literature. RESULTS: This manuscript describes an illustrated key for the identification of 22 of 23 mosquitoes which are currently recognized as local anopheline species in Sri Lanka, as a guide to workers engaged in malaria surveillance and control in the country. CONCLUSIONS: Revised morphological keys to the larval of these species may be helpful in easy and accurate identification at the field level.
A study on the relationship among culture, language and literary translation (with reference to selected literary works translated from English to Sinhala and vice versa)
(University of Kelaniya, 2015) Fernando, T.