What kind of mosquito transmits LaCrosse encephalitis?
• In Minnesota we have approximately 50 species of mosquitoes. Not all mosquitoes feed on people, and the primary vector of LaCrosse encephalitis is the Eastern Tree Hole mosquito (Ochlerotatus triseriatus). • The Tree Hole mosquito is found almost exclusively in wooded or shaded areas, and usually does not fly more than 200 yards from the area where it was produced. It feeds during the day, unlike many of our pest mosquitoes that feed mostly at dusk and dawn. • Tree Hole mosquitoes reproduce in water-holding tree holes (pockets of rainwater that collect between the main trunks of trees with two or more trunks). They also reproduce in waste tires, buckets, cans, and any other container that can hold rainwater. • The female Tree Hole mosquito can pass LaCrosse encephalitis virus into her eggs. In this way, the virus is maintained in the same areas year after year. If large numbers of water-holding containers are present in an area where LaCrosse virus is also present, there may be signi
