Sri Lanka Association for the Advancement of Science Proceedings of the 62nd Annual Sessions – 2006, Part I - Abstracts Sri Lanka Association for the Advancement of Science nd Proceedings of the 62 Annual Sessions 10 – 15 December, 2006 Part I - Abstracts Sri Lanka Association for the Advancement of Science - 2006 Sri Lanka Association for the Advancement of Science - 2006 ISSN 1391-023X Proceedings of the 62nd Annual Sessions Part I - Abstracts 10 – 15 December, 2006 2006 December (cid:148) The material in this publication has been supplied by the authors, and only major revisions, if relevant, have been done by the SLAAS. The views expressed remain the responsibility of the named authors and do not necessarily reflect those of the SLAAS. SLAAS or any other organisations or body sponsoring SLAAS activities cannot be held responsible for any material reproduced in this publication. Sri Lanka Association for the Advancement of Science Vidya Madiraya, Vidya Mawatha, Colombo 7, Sri Lanka Compiled by: Hema Goonatilake, Editor Preethi Randeniya, Assistant Editor Printed by Ananda Press (Private) Limited This publication is sponsored by the Ministry of Science & Technology MESSAGE FROM THE MINISTER OF SCIENCE AND TECHNOLOGY It is with great pleasure that I send this message on the occasion of the 62nd Annual Sessions of the Sri Lanka Association of the Advancement of Science (SLAAS). The SLAAS has brought together all the scientists in Sri Lanka to promote scientific research and increase scientific awareness among the public. It has also contributed to keeping abreast of scientific developments abroad. While continuing to play this important role, it is necessary that the scientists and technologists help the country to overcome the challenges posed by globalisation and contribute to achieving rapid economic development and overcoming poverty. This demands that the research effort should place more emphasis on development (development research) besides pure and applied research. Innovation has to play a key role in this process. The ultimate outcome must be high quality modern technology that would enhance productivity, resulting in goods and services being put on the market that can compete with those from abroad. The Science and Technology Awards Ceremony held on 10th November 2006 recognised the contribution of those scientists and technologists who best helped to generate the technology that the country needs in the presence of the President and other dignitaries. This will ensure that the extra money that the government is allocating for science and technology will be put to best use to benefit the country and its people. While Sri Lanka failed to benefit from the newer technologies like electronics, biotechnology and information communication technology to forge ahead industrially, we have a chance today to become a leader in Nanotechnology and develop industries based on this. The Budget has paved the way for this but we can succeed only if the commitment is there and the finances are made available in time, and the scientists respond. The process of taking science and technology to the village is being promoted by the “Vidatha” programme. This has made satisfactory progress but there is still a long way to go and the support of the scientific community is vital for its success. Taken together with the “Gama Neguma” Programme of the President, a real impact can be made to reduce rural poverty by creating employment opportunities. I hope that the scientists and technologists of Sri Lanka led by the SLAAS will make an active and significant contribution to the process that is taking place. I wish you a very successful Annual Session. Prof. Tissa Vitarana MP Minister of Science and Technology Vidatha programme of the Ministry of Science and Technology (“Gamata Thakshanaya”) We invite the scientific community to participate in this programme. Contact: Mrs. P G P Abeyratne, Additional Secretary Ministry of Science & Technology, 561/3, Elvitigala Mawatha, Colombo 5 Tel: 011-2559095, Fax: 011-2510550 CONTENTS Section A 01 Medical, Dental and Veterinary Sciences Section B 16 Agricultural Sciences and Forestry Section C 49 Engineering, Architecture and Surveying Section D 66 Life and Earth Sciences Section E 89 1 Physical Sciences Section E 112 2 Chemical Sciences Section F 132 Social Sciences POSTERS Section B 169 Section D 190 Section E 194 1 Section E 195 2 SECTION A 001/A Entomological and sociological investigations in dengue transmission areas in the Matale district A M G M Yapabandara* and D M L S Bandara Regional Office, Anti Malaria Campaign, Matale Entomological and sociological surveillances were carried out, to determine the key premises and containers suitable for Aedes aegypti and Aedes albopictus breeding in the selected dengue and Dengue Hemorrhagic Fever (DHF) transmission areas of the Matale District from 2004 to April 2006. Serologically or clinically identified dengue/DHF cases were collected from the Regional Epidemiologist, Matale. All the cases were investigated and 124 indigenous cases were randomly selected. Entomological surveillance was carried out around these cases, covering an area of 100 m radius of each case using standard methods. A sociological survey was carried out at the same time using a questionnaire. A total of 9133 water filled containers positive for Aedes aegypti and Aedes albopictus were encountered around 9661 places consisting of houses, dumping yards, government institutions and commercial sites. Eight types of artificial and natural containers namely, indoor and outdoor ground level water storage tanks and barrels, discarded receptacles, tyres, leaf axils of some plants and ornamental containers, refrigerator trays and roof gutters served as breeding places of vectors. Of all the types of water filled containers, a high proportion of outdoor ground level water storage cement tanks (48.47%) and discarded receptacles (34.39%) were infested by Aedes aegypti and Ae. albopictus larvae. The containers left outdoors (96%) showed a higher frequency of breeding vectors than those kept indoors. Middle income houses were significantly more likely to have Aedes larvae-infested containers than high (W=213, n=12, P=0.003) and low income premises (W= 78, n=12, P<0.001). These results suggest that Ae. aegypti and Ae. albopictus control programmes could be more cost effective and sustainable by concentrating efforts on key premises and key containers to control mosquito densities and dengue transmission while reducing manpower needs and insecticide use. *[email protected] Tel: 066-2222295 002/A Sensitivity of different larval collection methods in dengue vector surveillance in the Kandy and Nuwara Eliya districts P H D Kusumawathie1*, G A J S K Jayasooriya1 and A R Wickremasinghe2 1Regional Office, Anti Malaria Campaign, Dutugemunu Mawatha, Watapuluwa, Kandy 2Department of Community and Family Medicine, Faculty of Medicine, University of Kelaniya, Ragama A study was carried out during the period June 2005 - May 2006 in the Kandy and Nuwara Eliya districts to determine the sensitivity of 1, 5, 10 and 15 larvae collection methods in dengue vector surveillance. Aedes larval surveys were conducted at 19 sites in 17 Divisional Director of Health services areas of the two districts. In each survey, a minimum of 100 houses were visited, all possible indoor and outdoor Aedes breeding sites were examined. Twenty Aedes larvae were collected randomly in groups of 1st , 2nd-5th, 6th-10th, 11th- 15th and 16th- 20th larvae, in separate containers, from each positive container (If a particular container had < 20 larvae, all larvae were collected and grouped as previously). Larvae were identified to species. Sensitivity of 1, 5, 10 and 15 larvae collection methods were determined taking the 20 larvae collection method as the gold standard. Five Aedes species, namely, Aedes aegypti, Ae. albopictus, Ae. chrysolineatus, Ae. macdougalli, and Ae. vittatus were found to be breeding in the containers in the study sites. Of the 353 positive containers, 236 (66.86%) were positive for a single Aedes species, 110 (31.16%) for two species and 7 (1.98%) for 3 species. For Ae. aegypti, the sensitivities of 1, 5 and 10 larval collection methods were 68.26 (95% CI: 59.32 – 77.21), 91.35 (95% CI: 85.94 – 96.75) and 99.03 (95% CI: 97.16 – 100.0), respectively. 100% sensitivity was observed in 15 larvae collection methods. For Ae. albopictus, the sensitivities of 1 and 5 larvae methods were 74.66 (95% CI: 68.93 – 80.39) and 95.48 (95% CI: 92.73 – 98.22), respectively. Ten and 15 larvae collection methods were 100% sensitive. It is recommended to collect a minimum of 10 Aedes larvae (or all if < 10 larvae), to achieve a > 99% sensitivity for dengue vector surveillance. Entomological teams should be well trained in differentiating Aedes larvae from non-Aedes larvae in the breeding habitat, in order to prevent collection of non- Aedes larvae that occur commonly in the breeding sites of Ae. aegypti and Ae. albopictus. Tel: 081-2210687 003/A A study on the usage of anthelmintics among mothers in the Colombo district C Siriwardena, V P Palihawadana, G S A Gunawardena, M M Ismail and S D Fernando* Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo 8 This is a descriptive cross sectional study to assess the knowledge of the mothers living in urban and rural areas of the Colombo district with regard to the use of anthelmintics for their children. The study population comprised of 200 mothers (100 each from urban and rural areas). A pre-tested interviewer administered questionnaire was used to collect data on income, educational background, knowledge, attitudes and practices with regard to anthelmintic usage. No statistically significant effect of maternal age ((cid:548)2=0.76; p=0.86), parity ((cid:548)2=0.50; p=0.48), or residence -urban/rural ((cid:548)2=0.13; p=0.75) was observed on the use of anthelmintics. The rural mothers appear to commence deworming their children at an earlier age than their urban counterparts ((cid:548)2=8.47; p=0.04). Mothers who had studied up to tertiary level were less likely to deworm their children ((cid:548)2=23.71; p<0.01). The name of anthelmintic drug prescribed was known by 29.2% of urban and 35.9% of rural mothers ((cid:548)2=1.96; p=0.37). Only 12% (n=25) were aware that anthelmintics could cause minor side effects and this knowledge was similar in the urban and rural mothers ((cid:548)2=0.35; p=0.56). Among them only 44% could think of at least one side effect correctly. The General Practitioner was a significant source of anthelmintics with 63.8% (n=67) urban and 71.2% (n=74) rural mothers obtaining exclusively from a General Practitioner ((cid:548)2=4.11; p=0.25) and the price of the drugs varied from less than Rs. 20/= to more than Rs. 200/=. Among anthelmintic users, 70.0% gave anthelmintics regularly even in the absence of symptoms. This was of borderline significance (p=0.04) between urban and rural populations. (urban 63.4%, rural 76.8%; (cid:548)2=4.28; p=0.04). The majority (79%) believed that anthelmintics were safe to use during pregnancy (urban 72.1%, n=75; rural 85.0%, n=91; (cid:548)2=5.26; p=0.02). The basic knowledge regarding anthelmintics and their use is not satisfactory among mothers. As a majority of mothers received treatment from the General Practitioners, a more active role by them in educating patients is recommended. This study indicates that mothers who had a higher educational level used less anthelmintics. Hence special measures would have to be undertaken to address this group. *[email protected] Tel: 011-2695300 Ext. 341 004/A Genetic complexity of Plasmodium vivax infections in Sri Lanka W T A Wickramarachchi1, P H Premaratne1, K V G S Dias1, S M Handunnetti2,3, A M Gunasekara4, D F Wirth4 and P V Udagama-Randeniya1* 1Department of Zoology, Faculty of Science, University of Colombo, Colombo 3 2Malaria Research Unit, Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo 8 3Institute of Biochemistry, Molecular Biology and Biotechnology, University of Colombo, Colombo 3 4Department of Immunology and Infectious Diseases, Harvard School of Public Health, USA Using Plasmodium vivax Merozoite Surface Protein-3(cid:302) (PvMSP-3(cid:302)) marker, the existing genetic complexity of P. vivax infections was evaluated in individuals (N=146) from two malaria endemic areas, Kataragama (N=68), Anuradhapura (N=39) and from Colombo (N=39), a non-endemic region of Sri Lanka. A combination of polymerase chain reaction / restriction fragment length polymorphism (PCR/RFLP) techniques was used for this assessment. Undigested PCR products showed a major size polymorphism. The product sizes were approximately 1900, 1500 and 1200 bp among which the former was the most predominant (72.8%), while the other two accounted for 25.8% and 1.4%, respectively. The predominance of the 1900 bp product was more significant [Chi square test: (with 1500 bp; P<0.05) and (with 1200 bp; P<0.01)] than the other two products in all three study areas. Despite the presence of only three size variations in undigested PCR products, RFLP analysis yielded highly diverse fragment sizes and banding patterns for all samples. The RFLP patterns of all isolates showed size conservation of the largest fragment obtained from Hha I digestion (~1,000 bp) and Alu I digestion (~500 bp), while smaller fragments showed considerable size variation. The summation of RFLP fragments of 27 samples (19%), was significantly greater than the size of the undigested product, indicating the presence of more than one PvMsp-3(cid:302) allele in these infections. The number of these multiclonal infections was significantly higher (Chi square test; P<0.05) in the two endemic areas as compared to the non-endemic area. From the samples in which single clonal infections were detected, where smaller fragments resulted from RFLP digestion, at least 10 different banding patterns from each restriction enzyme were detected, indicating the presence of a substantially high diversity at the nucleotide level. These results demonstrate the prevailing genetic complexity among individual P. vivax infections in Sri Lanka, and also confirm the suitability of utilizing PvMsp-3(cid:302) locus to analyze the degree of polymorphism as well as clonality of P. vivax infections in this geographical region. Financial support by the National Science Foundation, Sri Lanka [Grant NSF/RG/2005/HS/06 and scholarship for PHP (NSF/SCH/2004/07)] is acknowledged. *[email protected] Tel: 011-2503399 006/A An audit of research output and membership characteristics of Section A, SLAAS R J Peiris-John* Faculty of Medical Sciences, University of Sri Jayewardenepura, Gangodawila, Nugegoda An audit was conducted using membership records and published abstracts in the last 61 years available in the SLAAS office. For an analysis of membership characteristics and participation in activities of SLAAS section A, a questionnaire was included in the section A newsletter and the responses analysed. Section A has contributed to the scientific sessions of SLAAS since 1947. Overall 1,287 presentations have been made at the sessions during the past 61 years. In the first 10 years, a total of 64 presentations were made. During the past 10 years, 320 presentations have been made. Of these, 264 presentations were on research conducted in Medicine and related fields, 11 in the Veterinary Sciences, 5 in the Dental Sciences and 40 in Ayurvedic Medicine and related fields. A majority of the papers submitted on Medicine and related fields were from the University of Colombo (n=130), Peradeniya (n=52), Sri Jayewardenepura (n=35), Kelaniya (n=18) and Ruhuna (n=17) and the anti-Malarial campaign (n=18). The majority of abstracts from the University of Colombo during this period were in the sub-specialties of Parasitology (n=55), Biochemistry & Molecular biology (n=24) and Indigenous medicine (n=12). In the last 3 years, there have been no presentations from the Medical Research Institute, Dental Institutions or from the hospitals under the Ministry of health. As at end 2005, Section A has members from only 16 of the 25 districts in the country. Of the 343 members whose private addresses are available, 69% are resident in the Colombo district, 10% in the Kandy district, 7% in the Gampaha district and 5% in the Galle district. This analysis revealed membership characteristics of highest academic excellence in both men and women. Expertise in a wide array of sub-specialties of the medical, dental and veterinary sciences is available. The decline in numbers of research papers in the recent past may be because researchers prefer to present their findings in the Associations in the different sub-specialties in Medicine, Dental and Veterinary Sciences rather than in the general research forum of SLAAS. However, the lack of representation in the membership from 9 of the districts is a matter of concern. It is important that Section A develops strategies necessary to harness the expertise to achieve the stated objectives of SLAAS. *[email protected] Tel: 011-2802182 007/A DNA-based parentage testing in forty cases of statutory and aggravated rape: Some social issues S Mohotti, T De Silva, R J Illeperuma and N D Fernandopulle* Genetech Molecular Diagnostics, 54, Kitulwatte Road, Colombo 8 This study examines forty cases of paternity testing that was performed in incidents of statutory and aggravated rape. Thirty one cases of statutory rape were selected on the basis that the tested mothers were below the age of 16yrs at the time of conception, and nine cases of aggravated rape were selected because the tested mothers were physically or mentally handicapped. The objective of this study was to observe trends in the parentage testing process for these two offences, and to examine the DNA typing data for possibilities of consanguinity between parents, which is indicative of unreported cases of incest. These cases were referred to us by Courts in 13 districts. In the statutory rape cases, the age of the mother ranged from 11yrs to 16yrs at the time of delivery with an average of 14.7yrs. The age of the father ranged from 15yrs to 56yrs with an average of 28.8yrs. Of the forty cases, 25 (62.5%) proved to be positive in the paternity test, and 15 (37.5%) proved to be negative. A negative result indicates that the accused is not the biological father. By extension, it also means that the actual father/rapist was not accused, and was not brought to trial in that case. We further examined the DNA data from the cases which gave negative results. We observed that of the degree of homozygosity in the child (3.0) was greater than in the overall average (2.6) for a random Sri Lankan. Further, we observed that the genetic similarity between mother and child in these cases was 3.3, which is greater than the national average (2.3) for a mother-child duo in the Sri Lankan population. A greater degree of homozygosity in the child and genetic similarity between the tested mother and child is strongly indicative of consanguinity between the actual parents of the child. From the above observations, it was found that there was a distinct possibility that in these cases, the rapist was a close family relative, and that another person had been falsely accused of the offence. In the above cases, we informed the Court of the possibility that the actual father may be a blood relative of the mother. However in all such cases, we were not requested to perform any further tests. As a consequence, in these cases the offence of statutory rape which is also incest went unprosecuted, and the offender was not even brought to trial. While a positive DNA test is very good proof of statutory and aggravated rape, a negative DNA test result must be further investigated for the underlying cause, which is likely to be the grievous offence of incestuous statutory rape, and all possible suspects must be subjected to testing in order to determine the identity of the rapist. *[email protected] Tel: 011-2696992