Browsing by Author "Dilani, P.V.D."

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Genetic improvements to the sterile insect technique (SIT) for the control of mosquito population
(Springer, 2021) Dilani, P.V.D.; Gunawardene, Y.I.N.S.; Dassanayake, R.S.
Mosquito-borne diseases are becoming a major health problem worldwide. At present, the principal method of controlling these diseases entirely depends on the mosquito vector control strategies. However, traditional control methods which are focussed on reducing mosquito populations through environmental management and the application of insecticides are largely ineffective. Hence, various control methods, including the release of sterile insect technique (SIT), have been proposed for the reduction of the mosquito population. As a species-specific control strategy, SIT offers considerable environmental benefits and a chemical-free option for insect control. However, the application of the SIT to mosquito control consistently suffered from lack of efficient sexing system, high fitness cost and operational difficulty in ionizing radiation, density-dependent nature of the target mosquito population and various other technical issues. The intervention of genetic engineering has led to several improvements in the operation or security of SIT programmes. The advent of mosquito transgenesis has paved the way for novel approaches in mosquito control. One possibility is a release of insects carrying dominant lethal (RIDL) strategy by engineering self-limiting gene, which offers solutions for many drawbacks of traditional SIT by providing genetic sterilization, genetic sexing, genetic containment and provision of genetic markers while maintaining its environmentally benign and species-specific utility. The success of this strategy often depends on how genetic modification affects the fitness of the mosquitoes. With several improvements and modifications allowing minimum fitness load, RIDL is now available for a wide range of mosquitoes such as Aedes aegypti, Aedes albopictus and Anopheles stephensi with field-testing possibilities. However, with solid epidemiological evidence and community support, widespread implementation of these strategies might reverse the current alarming global mosquito vector-borne diseases.
Hemocup blood feeder: An affordable and simplified blood-feeding device for maintenance of aedes aegypti mosquito colonies in Sri Lanka
(Academic Press, 2023) Dilani, P.V.D.; Wickramasinghe, P.D.S.U.; Lakshman, G.V.C.P.; Ranathunge, T.; Dassanayake, R.S.; Silva, G.Y.I.N.
Dengue is a mosquito-borne viral disease mainly transmitted by Aedes aegypti and disease control is primarily reliant on mosquito vector control strategies. In the failure of conventional vector control strategies, new strategies are being developed which specifically require the maintenance of mosquito colonies in the laboratories. Blood-feeding is an essential part of the routine colony maintenance of Ae. aegypti. Therefore, the current study was focused on developing a simplified artificial membrane-feeding device, "Hemocup" feeder out of affordable material. viz., plastic cups, styrofoam insulation system, parafilm-M, and preheated water to facilitate the Ae. aegypti artificial blood feeding. The performance of the device was compared to that of a commercially available blood-feeding device, "Hemotek", by assessing the blood-feeding rate, fecundity, and egg hatchability. Similar blood feeding rates were observed for Hemocup and Hemotek methods (91.8 ± 1.6 and 94.3 ± 1.6 respectively>0.05) as well as comparable fecundity between the two methods (20.8 ± 0.7 and 22.0 ± 1.5 respectively; p > 0.05). Furthermore, there was no statistically significant difference in egg hatchability between the two methods (91.9 ± 1.4 and 93.8 ± 1.4, respectively; p > 0.05). The results indicate that this simple Hemocup blood-feeding system can be used for routine colonization of laboratory strains of Ae. aegypti and for mass-rearing purposes.