Emerg Infect DiseidEmerging Infectious Diseases1080-60401080-6059Centers for Disease Control98667392640261Research ArticleIntroduction of Aedes albopictus into a La Crosse virus--enzootic site in Illinois.KitronU.ukitron@uiuc.eduSwansonJ.CrandellM.SullivanP. J.AndersonJ.GarroR.HaramisL. D.GrimstadP. R.College of Veterinary Medicine, University of Illinois, Urbana 61801, USA.Oct-Dec199844627630

In late summer and fall 1997, Aedes albopictus mosquitoes were found in Peoria, Illinois, a long recognized focus of La Crosse virus transmission. Larvae were found in tires and other artificial containers, biting adults were recovered, and eggs were collected in oviposition traps within a 25-ha area. One chipmunk trapped < 0.25 km from the infested area tested positive for neutralizing antibodies against La Crosse virus.