PI(s): Brewster, Carlyle C (Co-Project Leader), Paulson, Sally L (Co-Project Leader)

Investigators: Jackson, Bryan T (Investigator), Troyano, Nancy M (Investigator)

Abstract: La Crosse (LAC) virus is the leading cause of pediatric encephalitis in the U.S. Since its discovery approximately 40 years ago, most cases have been reported from the upper Midwestern states. However, in the past decade a southeastern focus of LAC virus has emerged with increasing numbers of cases being reported from West Virginia, Tennessee, North Carolina, and Virginia. Complicating the situation is the possible involvement of two non-native species of mosquitoes that have recently become established in LAC virus endemic areas. Isolation of LAC virus from several pools of mosquitoes collected in the New River Valley of southwest Virginia in 2002, an area from which no human cases have yet been reported, suggests that LAC virus may be continuing to expand its range in Virginia. The purpose of this research is to determine the extent of LAC virus activity in southwest Virginia. Two hypotheses are being tested in three regions in southwest Virginia. The first hypothesis is that accessory vectors, most specifically Ae. albopictus, are contributing to the increased incidence of LAC virus. Second, that canine seroprevalence can be used as a practical indicator of LAC virus transmission rates to vertebrates in an area.