Mosquitoes, most specifically the species Culex pipiens and Culex pipiens pipiens are the two believed responsible for the transmission of West Nile Like Encephalitis into a number of areas in the Eastern United States. We now know that other mosquito species may be a vector of this disease as well. Mosquito Basics First, the mosquitoes themselves.
Mosquitoes go through complete metamorphosis.
This includes the egg, larva, pupae and adult insects. While many species lay eggs in large bodies of standing water, Culex pipiens and Culex pipiens pipiens take advantage of microenvironments in areas such as blocked gutters, standing water in debris such as tires, wheelbarrows, planters and swimming pool covers, ditches, sink holes and other land depressions. When the eggs hatch in response to a sufficient amount of water, the larva actually float on the surface of the water. The water must remain fairly still or the larva will not survive. Encephalitis is vectored by migratory birds.