Aedes mosquito survey within the premises of University ofSri Jayewardenepura to determine its population density andseasonal shift in relative abundance

The Premises of the University of Sri Jayewardenepura was surveyed in the month of May for possible breeding habitats of mosquitoes which were mapped out and the immature stages of collected were identified. Subsequently investigations were made by placing ovitraps within the University premises from June to November 2008, to determine the abundance of Aedes aegypti and Aedes albopictus detected during the previous survey in the month of May. An Ae. aegypti positive container was detected only once in all the indoor and outdoor container observed and no Ae. Aegypti positive ovitrap was recorded during the study period. The Ovitrap Index (OI) for Ae. albopictus was calculated monthly. Breeding of Ae. albopictus was found in both indoor (Mean Monthly OI =13.3) and outdoor containers (Mean Monthly OI = 35.3). During the dry season the rainfall recorded a monthly range of 45.6 mm to 152.6mm. The larval population of Ae. albopictus remained low during this period with an Ol range from 0 to 12.5. However, during the rainy season which showed a monthly range of 294.9mm to 414.4mm, the Ol increased exponentionally (OI ranges from 13.3-80). In the month of September, Ae. albopictus were recorded in indoor ovitraps too (OI = 13.3), indicating its ability to replace the breeding places of Ae. Aegypti, under certain environmental conditions. The monthly dengue incidence reported from the neighboring area declined in the month of August and started to increase again in the month of September. The ecological conditions in these areas are very much similar to those within the University premises. The OI values of dengue vector mosquito species could be utilized to indicate a potential increase in the dengue incidence.