La Crosse encephalitis

[lə krôs]
n.
  1. An often fatal infection of the brain caused by a virus occasionally present in the bloodstream of birds and transmitted to humans by the mosquito Aedes triseriatus.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.