Medicine
Permanent URI for this communityhttp://repository.kln.ac.lk/handle/123456789/12
This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty
Browse
4 results
Search Results
Item 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.Item 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.Item 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.Item 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.