As the waters from Hurricane Katrina begin to recede, Gulf coast residents may have something else to worry about: mosquito-borne disease. Some scientists are concerned that the large, stagnant bodies of water that Katrina left behind will be ideal breeding grounds for vector mosquitoes, perhaps amplifying the low level of West Nile virus present in the area this season. However, experts also suggest that the hurricane may have wiped out most of the mosquitoes and birds that bring the disease to humans, making the region safer than before.