The U.S. is only home to about 6 percent of the world's 3,300 species of mosquitoes.
Enjoying the outdoors brings many people relaxation and a sense of unity with nature. However, it is not without its downsides, as the great landscapes of the U.S. are home to many insects, including about 200 species of mosquitoes. In Oregon, approximately 50 of these mosquito species can be found.
Culex Genus
In Oregon, perhaps the most important mosquito species to be aware of is Culex tarsalis. A known transmitter of West Nile virus, this species also actively spreads western equine encephalitis and St. Louis encephalitis. Its primary hosts are birds, but Culax tarsalis regularly bites humans after dusk. Other possible transmitters of West Nile virus found in Oregon include Culex pipiens and Culex stigmatasoma. Culex pipiens is a disturbing nighttime pest in Oregon's Willamette Valley, where it is known to enter homes frequently. Culex stigmatasoma can be found most readily in the western part of the state.
Aedes Genus
The species Aedes vexans has also been marked as capable of West Nile transmission and western equine encephalitis. Its presence is most notable in floodwater zones, especially those along the Columbia River and those tributaries up to 100 miles south of the Bonneville Dam. In the Cascades and Blue Mountains, particularly in the summer months, Aedes communis can be found in great numbers; this species is known to bite during the day, though as with most mosquitoes, they are more persistent at night. The plains of the state are home to Aedes increpitus, another common species which breeds in small, formed pools in woods or meadows.
Anopheles Genus
In such locations as Scappoose, Prineville, Klamath Agency and the Willamette Valley, large numbers of the species Anopheles freeborni make their homes. Now a carrier of western equine encephalitis, A. freeborni was once a prominent malaria carrier as well. Anopheles punctipennis is comparatively small in number, found mainly in the Cascade Mountain region, and breeds in clear pools. Anopheles punctipennis may once have partaken in the spread of malaria, but now it is of little medical concern to humans.
Culiseta Genus
Culiseta impatiens is not populous in Oregon. Found in forested areas, its female biters are rarely great enough in number to be a significant nuisance. As for Culiseta incidens, its greatest numbers are present in Oregon as well as Washington, notably west of the Cascades. Less is known overall about the species Culiseta minnesotee and Culseta particeps, though C. minnesotee is known to rarely attack humans and C. particeps breeds much like C. incidens and another species in this genus, Culiseta territans -- in pools with high concentrations of vegetative growth.
Tags: equine encephalitis, West Nile, western equine, western equine encephalitis, about species, Anopheles punctipennis, Culex pipiens