Efforts continue to reduce the high level of Culex mosquitoes on the island's south coast.
Daily fogging exercises are being conducted as health officials seek to control the proliferation of them in the area.
Deputy Chief Environmental Health Officer Ronald Chapman says their presence is due to spillage of sewage from the south coast treatment plant into areas of the Graeme Hall swamp.
One of the characteristics of this mosquito is that it breeds primarily in dirty water.
While noting there have always been mosquitoes in the swamp, Mr Chapman says they have increased the level of surveillance in the area, visiting householders and businesses, as well as keeping watch of activities within the Graeme Hall swamp.