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

Abstract

The Premises of the University of Sri Jayewardenepura was surveyed in the month of May forpossible breeding habitats of mosquitoes which were mapped out and the immature stages ofcollected were identified. Subsequently investigations were made by placing ovitraps within theUniversity premises from June to November 2008, to determine the abundance of Aedes aegypti andAedes albopictus detected during the previous survey in the month of May. An Ae. aegypti positivecontainer was detected only once in all the indoor and outdoor container observed and no Ae. aegyptipositive ovitrap was recorded during the study period. The Ovitrap Index (OI) for Ae. albopictus wascalculated 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 recordeda monthly range of 45.6 mm to 152.6mm. The larval population of Ae. albopictus remained lowduring this period with an Ol range from 0 to 12.5. However, during the rainy season which showeda 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 environmentalconditions. The monthly dengue incidence reported from the neighboring area declined in the monthof August and started to increase again in the month of September. The ecological conditions in theseareas are very much similar to those within the University premises. The OI values of dengue vectormosquito species could be utilized to indicate a potential increase in the dengue incidence.

Key words: Aedes albopictus, Dengue Fever, Qvitrap Index, Mosquito breeding habitats,Integrated Vector Control